The longest distance ever reported at single carrier 600G DWDM transmission on an SDM cable
The Amitié submarine cable features Space Division Multiplexing (SDM) technology with 16 fiber pairs, more than traditional subsea cables, with repeater power shared across the fiber pairs to deliver the highest cable capacity. This real-time field trial exceeded any industry trial performance to date with Dense Wavelength Division Multiplexing (DWDM) 800G in a 150GHz channel spacing, equivalent to a spectrum efficiency of 5.33bit/s/Hz and a maximum spectral efficiency of 5.6bit/s/Hz. In addition, 600G was transmitted over 12,469 kilometers for a trans-Atlantic loopback configuration. This is the first time a 140Gbaud single carrier signal was demonstrated live, and is the longest distance ever reported at single carrier 600G DWDM transmission on an SDM cable.

According to Jamie Gaudette, GM of Cloud Network Engineering, Microsoft, “The transmission of 800G over 6,234 kilometers is a milestone that demonstrates SDM cables can deliver increased capacity over traditional subsea cables. This field trial demonstrates what is now a commercial technology for subsea routes, and we can improve the network capacity to help drive digital transformation for people, organizations, and industries around the world.”

“In the era of AI, reliable and fast network connections are more important than ever,” said Bill Gartner, SVP Optical Systems and Optics, Cisco. “Working with Microsoft on the Amitié cable to demonstrate the potential for improved overall network capacity with 800G at these distances is a significant milestone for an SDM cable, and we’re proud to drive the innovations that pave the way for ever increasing network capacity needs.”

Trial Leverages the Latest in Terabit Optics
According to Microsoft and Cisco, this trial was conducted to target improvements in subsea transmission to provide increased performance and capacity. It was performed with the Cisco NCS 1014 platform enabled by Acacia’s CIM 8, which is powered by Acacia’s Jannu digital signal processor and advanced silicon photonics.

CIM 8 features 2^nd Generation 3D Shaping that provides a 20% higher spectral efficiency over the previous generation. CIM 8 also includes advanced non-linear equalization capabilities, an important feature for submarine links. Acacia has been a leader in deployed submarine-capable silicon photonics for almost a decade.

With this recent subsea trial, Microsoft is the latest provider to announce successful transmission with the CIM 8. Previously, China Mobile, NYSERNet, Verizon, and Windstream Wholesale announced their own trials.

Join the Terabit Era
If you’re ready to join the Terabit Era with CIM 8, contact us.

To date, multiple system vendors have converged around Class 3-based solutions (Figure 1), recently announcing their next generation offerings. This industry convergence creates the benefit of economies of scale and broad industry investments into the technology used in this baud rate class, the same class being used for 800G MSA pluggable solutions.

Figure 1.  Acacia and other coherent vendors have announced Class 3 Terabit Era solutions.

Advancements Resulting in 65% Power-per-Bit Savings Over Current Competing Solutions
Doubling the baud rate from Class 2 to Class 3 in silicon was a significant engineering achievement, combining design advancements in high-speed Radio Frequency (RF) and Analog to Digital Converter (ADC) and Digital to Analog Converter (DAC) components plus well-designed co-packaging integration of silicon and silicon photonic (SiPh) components. These achievements led to Acacia’s successful 140Gbaud in-house capability that is being leveraged in the commercially available CIM 8 solution.

With high-volume shipments of multiple coherent Class 2 module products utilizing Acacia’s 3D Siliconization, this proven co-packaging integration solution provided the foundation for extending this capability to Class 3 140Gbaud implementation utilized in the CIM 8 (Figure 2). 3D Siliconization maximizes signal integrity by co-packaging all high-speed components including the coherent Digital Signal Processor (DSP) application-specific integrated circuit (ASIC), transmitter and receiver silicon photonics, and 3D stacked RF components into a single device that is manufactured in a standard electronics packaging house. Silicon technology has demonstrated cost and power advantages over alternative technologies, making it the material system of choice for these higher baud rates. These advancements enabling a doubling of the baud rate have led to a 65% power-per-bit savings of CIM 8 over current competing solutions that utilize alternative optical material systems. In addition, the size and power savings of this latest generation enabled the ability to house this 1.2T 140Gbaud solution in a pluggable form-factor.

Figure 2.  An example of 3D Siliconization used in the CIM 8 module, resulting in a volume electronics manufacturable high-speed single device larger than a quarter.

2^nd Generation 3D Shaping Advances Coherent Performance
The CIM 8 is powered by Jannu, Acacia’s 8^th generation coherent DSP ASIC. The design greatly expands on the success of the Pico DSP ASIC predecessor used in the widely deployed performance-optimized Class 2 AC1200 module (Figure 1). The AC1200 was the first module to introduce 3D Shaping, which provided finely tunable Adaptive Baud Rate up to 70Gbaud as well as finely tunable modulation up to 6 bits/symbol. The AC1200 had achieved record breaking spectral efficiency at the time of its introduction, as evidenced by a subsea trial over the MAREA submarine cable connecting Virginia Beach, Virginia to the city of Bilbao in Spain. Finely tunable baud rate helps maximize spectral efficiency in any given passband channel, converting excess margin into additional capacity/reach, and avoids wasted bandwidth due to network fragmentation.

Figure 3.  A popular feature is the fine-tunability of baud rate introduced by Acacia with the Class 2 AC1200; CIM 8 incorporates the same Adaptive Baud feature (as part of 2^nd Generation 3D Shaping) for Class 3 baud rate tunability.

The 5nm Jannu DSP ASIC in CIM 8 intelligently optimizes optical transmission using 2^nd Generation 3D Shaping with an increased Adaptive Baud Rate tunable range up to 140Gbaud, as well as finely tunable modulation up to 6 bits/symbol using enhanced Probabilistic Constellation Shaping (PCS). With 2^nd Generation 3D Shaping, the CIM 8 module can achieve a 20% improvement in spectral efficiency.

Terabit Era Solutions Provide Full Network Coverage
Class 3 technology not only ushers in the terabit era, but also enables full multi-haul network coverage as the high baud rate capabilities transport nx400GbE client traffic across a service provider’s entire network. Full network coverage is not only enabled by adjustment of the modulation, but also implies the capability to optimize for various network conditions which include overcoming transmission impairments.

Figure 4. CIM 8 1.2T, 1T, 800G, and 400G transmission constellations operating at Class 3 baud rates providing wide network coverage addressing multiple applications.

CIM 8 offers significant power-per-bit reductions as well as cost efficiencies for various optical network transport applications.

DCI/Metro Reaches
For transporting 3x400GbE or 12x100GbE client traffic with metro reaches in a single carrier, the CIM 8 is tuned to ~6 bits/symbol (equivalent to 64QAM, example constellation on left). Data center interconnect (DCI) applications would take advantage of this high-capacity 1.2T transport capability to tie data center locations together. This amounts to 38.4T per C-band fiber capacity.

Long-Haul Reaches

For transporting 2x400GbE with long-haul reaches, the CIM 8 is tuned to ~4 bits/symbol (equivalent to 16QAM, example constellation on the right). Wide 800G network coverage is achieved with the Class 3 140Gbaud capabilities enabling service providers to provide end-to-end 2x400GbE, 8x100GbE, or native 800GbE transport across their networks, covering essentially all terrestrial applications.

Ultra-Long-Haul/Subsea Reaches

And for ultra-long-haul/subsea reaches, the CIM 8 is tuned to ~2 bits/symbol (equivalent to QPSK, example constellation on the left). As with the previous scenarios, spectral efficiency with a wavelength channel is optimized by fine-tuning of the baud rate. These high spectrally efficient modes can carry mixed 100GbE and 400GbE traffic over the longest subsea routes in the world with lowest cost per bit. It’s worth noting that almost a decade ago, Acacia demonstrated SiPh capabilities for subsea coherent deployments. CIM 8 incorporates second generation non-linear equalization (NLEQ) capabilities to mitigate the non-linear effects of optical transmission especially for these ultra-long-haul/subsea links providing additional OSNR.

In all the above scenarios, the CIM 8 utilizes advanced power-efficient algorithms to compensate for chromatic and polarization dependent dispersion. In addition, the module accounts for coverage of aerial fiber network segments that require fast state-of-polarization (SOP) tracking and recovery due to lightning strikes. The SOP tracking speed of CIM 8 is double the speed of its predecessor. This fast SOP tracking feature can also be utilized for sensing applications.

Network Operators Achieve Record Breaking Field Trials with CIM 8
CIM 8 capabilities have already been put to the test as illustrated by multiple record breaking field trials across a wide range of applications. These include >5600km 400G transmission over a mobile carrier’s backbone network, 2200km 800G transmission over a research and education network, and >540km 1T transmission over a wholesale carrier’s network.

Acacia continues to demonstrate its technology leadership by leveraging mature knowledge in proven silicon-based coherent technology, producing the first shipping coherent solution to lead the industry into the Terabit Era with the 1.2T pluggable CIM 8 module. With the breakthrough capability of 140Gbaud transmission along with the advanced Jannu DSP ASIC using 2^nd Gen 3D Shaping and leveraging 3D Siliconization, network operators can support full network coverage for multi-haul applications, especially to support growing demands for nx400GbE and upcoming 800GbE traffic.

References:
Blog: Terabit Today: Maximize Network Coverage
Blog: How Industry Trends are Driving Coherent Technology Classifications
Blog Series: The Road Ahead for Next-Generation Multi-Haul Designs Part 1, Part 2, Part 3

Supporting data rates up to 1.2 terabits per second (1.2Tbps), the CIM 8 is the first commercial single optical carrier coherent transceiver that breaks into the “Terabit Era.” It is powered by Jannu, Acacia’s 8^th generation digital signal processor (DSP) ASIC, which is based on 5nm CMOS and features the latest in Silicon Photonic technology.  This solution delivers industry-leading performance in a small faceplate pluggable module by combining the Jannu DSP with 3D Siliconization packaging technology. The CIM 8 supports multi-haul applications by using second-generation 3D Shaping technology and continuous baud rate adjustment up to 140Gbaud, enabling customers to scale their networks efficiently and cost-effectively.

“The ability to maximize transmission data rate across a wide range of multi-haul network applications is key for cost-effectively scaling networks,” said Bill Gartner, SVP / GM Optical Systems and Optics Group at Cisco.  “Not only does the CIM 8 deliver exceptional performance, but it also consumes less than half the power per bit of competing solutions, allowing us to support terabit transmission with a small pluggable module.”

“Shipping CIM 8 Terabit Era optical transceivers with 140Gbaud capability to customers and seeing them tested in carrier networks is very exciting,” said Mehrdad Givehchi, VP of Engineering for Acacia. “Delivering the highest channel capacity and longest reach with maximum fiber utilization, the CIM 8 transceiver enables a wide range of multi-haul network applications including DCI, metro, long-haul, and subsea.”

Benefits of Increased Baud Rates

Increasing baud rate is an efficient way to enable more cost-effective optical networks by reducing the number of optics needed to support a given transmission capacity. By doubling the baud rate between successive generations, CIM 8 supports twice the capacity per carrier over greater reaches than earlier generations such as our widely deployed AC1200 coherent module. Three 400GbE client interfaces can be transmitted over virtually any network application, delivering 1.2Tbps per carrier capacity for high-capacity DCI interfaces, 800G per carrier capacity over most optical links using 4 bits/symbol (~16QAM) modulation and 400G QPSK over ultra-long-haul and subsea distances.

Performance Optimizing Features Enabled by the Jannu DSP

A key feature of the Jannu DSP is Acacia’s second-generation 3D Shaping technology, which includes advanced Probabilistic Constellation Shaping, Adaptive Baud Rate, and enhanced transmission impairment compensation algorithms providing superior performance using a single carrier implementation. This technology gives service providers unprecedented transmission flexibility to match their network’s architecture, optimize fiber utilization, simplify deployment, and save on both CAPEX and OPEX.

The Jannu DSP provides customers with continuous baud rate adjustment up to 140Gbaud and continuous modulation to optimize utilization of available spectrum in point-to-point DWDM or cascaded ROADM paths. As a single carrier design, the Jannu DSP incorporates Acacia’s most advanced line-rate processing algorithms to efficiently overcome fiber transmission impairments across various fiber types and fiber cable installation conditions. These power-efficient algorithms are designed to compensate fiber non-linearity to achieve longer transmission distance, automatically compensate for very large chromatic dispersion over trans-Pacific submarine cables, tolerate older deployed fibers with high Polarization Mode Dispersion, as well as provide fast state-of-polarization tracking required for aerial fiber cables in stormy weather conditions.

Leverages Acacia’s 3D Siliconization

The CIM 8 continues Acacia’s history of technology leadership by delivering industry leading performance based on the same silicon photonics used in high-volume pluggable modules. 3D Siliconization, a key enabler for the industry leading 140Gbaud, uses highly scalable and reliable volume semiconductor manufacturing processes, leveraging 3D stacking technology to enable a single packaged device to include all the high speed electrical and opto-electronic functions necessary for coherent transceivers. This device decreases footprint by integrating the DSP, Photonic Integrated Circuit, modulator drivers, and Transimpedance Amplifiers, and is manufactured using standard CMOS packaging processes that offer improvements in reliability, cost, and volume scaling.

To learn more, visit the Coherent Interconnect Module 8 page or contact us.

Supporting Resources

Acacia Unveils Industry’s First Single Carrier 1.2T Multi-Haul Pluggable Module

How Industry Trends are Driving Coherent Technology Classifications

The Road Ahead for Next Generation Multi-Haul Designs (Part 1 of 3)

The Road Ahead for Next Generation Multi-Haul Designs (Part 2 of 3)

The Road Ahead for Next-Generation Multi-Haul Designs (Part 3 of 3)

100GBaud+ Silicon Photonics Solutions Drive Optical Network Evolution

That means 1) knowing what traffic granularity they need to transport and then 2) scaling the capacity in their transport network so that it aligns with the traffic granularity they need to move.

In addition, operators are looking for a common solution that can maximize network capacity over the widest network coverage. This can provide the ability to scale to higher capacity in a cost-effective way.

400GbE is Today’s Unit of Currency
Networks are evolving from 100GbE to 400GbE dominant traffic. As Telia Carrier stated, “400G: it’s here and huge!.” Network operators now need to figure out a way to build their networks to best support 400GbE traffic. True multi-haul solutions have emerged to meet this need because they were designed to be a flexible solution for DCI, metro, long-haul and subsea applications. However, a multi-haul solution is only effective if it can carry the different types of traffic it needs to transport while maximizing the value of existing infrastructure and reducing operational costs.

Multi-haul solutions maximize fiber utilization and simplify deployment.

Modulation Order Drives Design Decisions
Class 2 implementations utilizing 4 bits/symbol (~16QAM) and 60-64Gbaud have been standardized in the industry because they address a wide range of DCI and service provider metro applications as networks transition to 400GbE. Multi-haul implementations allow even greater reaches using approximately 4 bits/symbol with shaping and higher gain forward error correction algorithms. Class 2 multi-haul products transport 400GbE clients over the majority of network applications using 4 bits/symbol, with the ability to dial down the modulation format to 2 bits/symbol for the most challenging ultra-long-haul links.

Looking to Class 3 multi-haul products, efficient transmission of 400GbE traffic can best be achieved by doubling the baud rate to 120-128Gbaud. This enables 4 bits/symbol transmission supporting 800G line rates and 2 bits/symbol supporting 400G line rates. In high-capacity edge applications, these Class 3 products can support up to 1.2T line rates. By aligning client traffic granularity with the modulation orders that can best support network applications, identifying the preferred baud rate for Class 3 implementations becomes straightforward.

The industry has standardized on Class 2 implementations utilizing 4 bits/symbol (~16QAM) and 60-64Gbaud for various 400G implementations that address a range of DCI and service provider network applications.

Maximizing Network Application Coverage
A recently introduced Class 3 multi-haul solution, Acacia’s Coherent Interconnect Module 8 (CIM 8), can address transmission of multiple 400GbE client interfaces over virtually any network application, delivering 1.2T per carrier capacity for high-capacity DCI interfaces, 800G per carrier capacity over most optical links using 4 bits/symbol (~16QAM) modulation, and 400G per carrier over long-haul and subsea links.

Leveraging actual data from representative networks, the below simulation shows that the CIM 8 can effectively address subsea applications with 400G links, long-haul and metro with regional 800G (2x400G) and DCI and metro networks with 1.2T.  This means that the CIM 8 can provide efficient transport of 400GbE client traffic across the entire network, including 90 percent coverage using 800G (2x400GbE client traffic).

Utilizing data from actual service provider networks, Acacia’s CIM 8 can provide ~90% 800G network coverage compared to <20% for ~96Gbaud systems.

Scaling Efficiently and Cost-Effectively Today and Tomorrow
Network operators are being challenged more than ever before to scale their networks efficiently and cost effectively. Key to achieving this is knowing what kinds of traffic they are transporting and then building the right system that can most effectively transport that traffic.

As we approach Shannon’s Limit, further improvement will come from going to higher baud rates, but in a cost-effective way. As this article has discussed, having one solution that can be leveraged across all the various applications can enable an efficient and cost-effective solution for network operators looking to scale their networks today and in the future.

1.2T Delivering Maximum Capacity, Reach & Fiber Efficiency

Acacia, now part of Cisco, is once again introducing a ground-breaking coherent solution with the industry’s first 1.2 terabits per second (1.2T) faceplate pluggable coherent module, highlighting a new 8th generation Coherent Interconnect Module family, powered by Acacia’s Jannu 5nm CMOS digital signal processor (DSP) ASIC. This solution delivers industry-leading performance with single carrier 1.2T operation and combines the Jannu DSP with 3D Siliconization packaging technology which includes the silicon photonics integrated circuit (SiPh PIC), high-speed modulator driver and transimpedance amplifier (TIA) in a single optoelectronic package.

The Jannu DSP is designed to offer network operators the ability to maximize transmission data rate across a wide range of multi-haul network applications including DCI, metro, long-haul and subsea. “By leveraging the latest 5nm CMOS process node and our advanced signal processing algorithms, we’re delivering exceptional performance with less than half the power per bit of competing solutions, enabling a pluggable deployment model,” says Christian Rasmussen, Sr. Director, DSP and Optics Engineering and Founder at Acacia.

The Industry’s Next Class of Coherent Interconnect

The architecture of the new Coherent Interconnect Module 8 (CIM 8) solution builds upon the success of the Acacia AC1200 product family and aligns closely with the latest client data rates and coherent industry standardization efforts. The CIM 8 is designed to enable network operators to double their transmission capacity over even greater reaches. For links requiring maximum capacity, the new module can provide 1.2T capacity over a single wavelength.

“Historically, Acacia has been a groundbreaker in advancing coherent technology, and the company continues to demonstrate a long-term vision for how multi-haul coherent optics should evolve over time,” said Dr. Scott Wilkinson, Lead Analyst for Optical Components at Cignal AI. “Acacia’s new Coherent Interconnect Module is a great example of market leadership. This solution is a logical next step following the widely adopted Pico DSP-based products and will provide pluggability that is attractive to both traditional and cloud operators.”

The below figure illustrates how coherent technology has evolved in response to growing bandwidth demands. Different baud-rate classes are grouped based on technological capabilities, industry standardization (such as OIF, IEEE, Open ROADM, OpenZR+ MSA, CableLabs, ITU) and common industry investments. As the below figure depicts, the next class of coherent optical products, Class 3, enables a doubling of baud rates from the current Class 2 technology. Class 2 products include both multi-haul embedded modules and 400G faceplate pluggables where the latter was driven by standardization efforts that drove heavy investments into products centered around 16QAM, 60+Gbaud per 75GHz channel transmission.

Throughout this evolution, it has been critical that each successive class provide network architecture compatibility to the previous class, primarily reach and channel width. Acacia’s Class 3 product will support 150GHz channels with double the capacity per carrier and longer reach than that of the previous class, providing a simple, scalable path that is compatible with the previous network architecture generation.

The CIM 8 family is a Class 3 solution that can address transmission of multiple 400GbE client interfaces over virtually any network application, delivering 1.2T per carrier capacity for high-capacity DCI interfaces and 800G per carrier capacity over most optical links using 4 bits/symbol (~16QAM) modulation.

Leading in Performance and Fiber Utilization

The Jannu DSP features Acacia’s second-generation 3D Shaping technology, which leverages enhanced probabilistic constellation shaping (PCS) algorithms and Adaptive Baud Rate, a feature introduced in Acacia’s Pico DSP and widely embraced by network operators. The Jannu DSP provides customers with continuous baud rate adjustment up to 140Gbaud to optimize utilization of available spectrum in a single-span or in cascaded ROADM paths. These 3D Shaping features give service providers unprecedented transmission flexibility to match their network’s architecture, optimize fiber utilization, simplify deployment, and save on both CAPEX and OPEX.

As a single carrier design, the Jannu DSP also includes Acacia’s advanced line-rate processing algorithms to efficiently overcome fiber transmission impairments over greenfield or brownfield fiber infrastructures. These power-efficient algorithms are designed to compensate for linear and non-linear impairments, as well as provide state-of-polarization (SOP) tracking with industry leading response times. In addition, the Jannu DSP leverages Acacia’s new innovative soft-decision error correction (SD-FEC) to further enhance performance.

Scaling Optical Network Architectures

Acacia has been working towards a clear vision of how to cost-effectively scale network capacity for many years. The Jannu DSP builds on the performance and architectural benefits that have made the Pico DSP such a successful Class 2 coherent solution, but with double the baud rate and enhanced performance that supports transmission up to 1.2T in 150GHz channels. With adaptive baud rate capabilities, the CIM 8 also offers maximum capacity over any reach and channel plan.

“Today is an exciting new milestone in Acacia’s history as we once again introduce an exciting new product that delivers the type of disruption needed to cost-effectively scale network capacity in the future,” said Mehrdad Givehchi, Sr. Director of Engineering for Hardware and Software and Founder at Acacia. “With every generation of product, we have been able to deliver higher transmission data rates, lower power consumption and higher performance and I am proud to see this new product carry on that legacy.”

Crossing the Pluggable Terabit Threshold with High-Density Integration

Acacia’s 3D Siliconization is a major contributing factor in how the CIM 8 can cross the terabit capacity threshold and support faceplate pluggable optics that simplify network deployment and maintenance. 3D Siliconization applies integration and 3D stacking packaging techniques to enable a single device to include all the high-speed optoelectronic functions necessary for coherent transceivers. This device decreases footprint by including the DSP, SiPh PIC, drivers, TIAs, and is manufactured using standard CMOS packaging processes that leverage the same reliability, cost, and volume scaling advantages. With 3D Siliconization, the high-speed RF interfaces are tightly coupled together, resulting in improved signal integrity for high baud rate signals.

The high-density packaging as well as an advanced high-speed modulator design provides superior frequency response that enables the 140Gbaud performance as explained in this white paper.

Acacia Technology Leadership and Vision

Transforming industry trends into a development strategy takes the kind of vision Acacia has repeatedly shown in driving the adoption of pluggable digital coherent optical (DCO) modules based on silicon photonics. However, Acacia’s silicon photonics expertise expands beyond just pluggable coherent solutions. As shown in the above figure, Acacia has previously introduced multi-haul products in previous classes. In fact, the AC400 Class 1 product was the first commercially deployed all silicon photonics-based coherent module for submarine applications and the silicon photonics-based AC1200 was the industry’s first Class 2 multi-haul solution. The newly introduced CIM 8 continues this history of technology leadership by providing industry leading performance based on the same silicon photonics used in high volume pluggable modules. In addition, Acacia is leveraging the investments being made in next-generation standardized solutions. Aligning these developments helps Acacia to accelerate time to market for both standardized and multi-haul products and benefit from the combined scale.

Acacia was a pioneer of silicon photonics for coherent applications in 2012 when it was the first coherent module vendor to envision silicon as the platform for the integration of multiple discreet photonic functions, increasing the density and reducing cost of optical interconnect products.

“Acacia’s vision and technology leadership has enabled us to transform coherent transmission. Our pioneering role in silicon photonics has led to the introduction of industry leading coherent pluggable and multi-haul solutions,” said Benny Mikkelsen, CTO and Founder of Acacia. “With every new product introduction, we have delivered the right solution at the right time to help our customers meet their growing bandwidth demands, and this new product introduction is a culmination of this proven technology leadership.”

To learn more, visit Coherent Interconnect Module 8 page or contact us.

Acacia was a pioneer of silicon photonics in 2012 when it was the first coherent module vendor to envision silicon as the platform for the integration of multiple discreet photonic functions while increasing the density and reducing cost of optical interconnect products. According to Gazettabyte, Acacia’s choice to back silicon photonics for coherent optics was an “industry trailblazing decision.”

Leveraging advancements in silicon photonics processing, Acacia was able to deliver generations of high-volume silicon photonics-based products that continually enabled higher transmission data rates, lower power, and higher performance than the generation before it. Early on, some skeptics dismissed silicon photonics as incapable of achieving the performance required for coherent optical transmissions over long-haul distances. As evidenced by today’s deployments of Acacia’s 1.2T multi-haul AC1200 coherent optical module in well over a hundred customer networks which include subsea, long-haul, regional, metro and DCI applications, it is clear that silicon photonics can achieve industry leading performance.

Today, Acacia’s solutions leveraging silicon photonics are available in a wide range of coherent optical interfaces, from edge and access to subsea applications, to enable high-speed transmission and excellent performance.

Acacia’s silicon photonics leadership timeline for coherent transmission.

The Power of Silicon Photonics

Using silicon as an optical medium and leveraging CMOS fabrication processing technology, silicon photonics allows tighter monolithic integration of many optical functions within a single device. While traditional optics systems used many discrete pieces, silicon photonics allows all those pieces to fit onto a single silicon chip.  This tight integration is what has allowed component vendors to continually drive reductions in the cost and size of optical solutions. For network equipment manufacturer customers, using the silicon photonics chip means they can design more ports per linecard, increasing the capacity of their system.

Below are a few reasons that silicon photonics has been so successful and has emerged as a key technology for existing and future optics solutions.

• Leverages CMOS Processes– Silicon photonics leverages the higher yields and lower cost associated with CMOS. Leveraging mature silicon process technologies means that much larger wafers can be made in silicon than traditional optics materials. Today’s silicon photonics solutions run on lines that accommodate up to 12-inch wafers or larger. These larger wafers result in an order of magnitude more dies per wafer, which lowers cost.
• Enables Package Level Integration – As the industry continues to move toward higher data rates and lower power, the interface between the DSP and high-speed optics is quickly becoming a bottleneck. Every time a high-speed signal needs to transition across an additional electrical interface (solder bumps, wire-bonds, vias, PCB traces) there is loss and distortion. Compensating for this additional loss adds power dissipation, and distortion limits performance. Using silicon photonics enables package-level integration that can better optimize these high-speed interfaces and accelerate the realization of higher data rates at lower power.  In addition, silicon photonics is temperature tolerant and thus is not affected by the heat-generating DSP.
• Ensures High Reliability –
  • Overall, silicon photonics increases reliability with the high level of integration reducing the number of component interconnects, which are a common source of failure
  • Traditional optics degrade in high-moisture environments, requiring optics to be packaged in costly hermetic gold boxes, which are historically one of the most common sources of failure for optics. Silicon, on the other hand, does not require hermiticity so by using silicon photonics the costly gold boxes are eliminated which improves reliability
  • In addition to having higher yields than traditional optics materials, silicon photonics can also be tested at the wafer level. Good die can be identified early in the process, and there is no labor wasted on material that will ultimately fail thereby reducing cost.
• Simplifies Deployment and Management – Pluggable modules with industry standard interfaces allow vendors to simplify their networks.

Higher baud rate designs

The next battle for the industry is achieving higher baud rates in a cost-effective way. As the gap to Shannon’s Limit narrows, it is becoming more difficult to increase channel capacity by increasing the modulation order while keeping the same transmission distance. This leaves higher baud rates as a preferred method to increase capacity and decrease cost per bit. Silicon photonics and advances in packaging technology enabled by silicon photonics are key for enabling higher baud rate designs.

Component Stacking

In component stacking, electrical impairments are reduced due to very short electrical connections between key RF components, creating a robust signal path for extremely high frequency/baud rate operation. In this stacked design, the gold-box packaging is eliminated, the DSP, and PIC are tightly co-packaged on the same substrate, and the high-speed modulator driver and TIA components are stacked on the PIC.  Stacked design has a higher (better) frequency response than the traditional gold-box design. Advanced stacking designs can further reduce interconnect impairments, resulting in even higher frequency response.

Illustration of example electrical interconnect frequency response comparing traditional gold-box and stacking integration shows that stacking provides a path to >100Gbaud.

New, Innovative Architectures and Future Innovations

Because of its ability to drive performance and volume manufacturability, silicon photonics has the potential to unlock new architectures needed to keep up with rising demand.  An example is pluggable coherent transceivers that can be plugged directly into switches and routers offering the same density for both coherent DWDM and client optics in the same chassis.  It can also drive future generations of optics design that push the envelope on performance, cost, complexity, and size.

The industry is now turning to silicon to produce a wide variety of devices, using mainstream silicon manufacturing process technologies that have matured over many years.  As optical transceivers need to support higher data-rate, driven by the demand for higher speed networks that can handle the rising bandwidth demand, we believe silicon photonics will once again allow the capacity to grow without significantly increasing the size and cost of the devices needed for the future. For this reason and the benefits discussed above, Acacia plans to use silicon photonics in all coherent applications going forward to help customers stay ahead of the curve.

As an example, Acacia’s high-performance Pico DSP-based 1.2 Terabit solution is currently deployed in well over one hundred networks around the globe and has been adopted by three of the four largest hyperscalers. In 2020 alone, Acacia shipped more than 30,000 Pico-based ports as customers increasingly recognized the competitive benefits that high-performance, flexible coherent transmission solutions can provide.

Network Transmission Flexibility Benefits

Multi-haul coherent solutions like the Pico DSP-based 1.2 Terabit solution are software configurable transponder modules that provide various transmission capacities and reaches. By varying the modulation order and baud rate settings, it can provide flexible options for service providers.

A multi-haul coherent solution addresses a range of network applications.

Balancing Modulation Order and Baud Rate

A common method of increasing throughput of a coherent channel is to increase the modulation order. However, this may result in a reduction in reach due to reduced optical signal to noise ratio (OSNR) tolerance for the higher modulation orders. Alternatively, the baud rate could be increased while maintaining a lower modulation order which provides additional capacity per channel with minimal sacrifice to reach.

Maximizing the channel capacity using continuously tunable baud rate can convert unused spectrum into usable capacity, with the goal to fill up the available channel bandwidth. However, as discussed in this whitepaper, increasing baud rate provides minimal improvements in fiber capacity once the transmission is well-matched to the channel.

Increasing transmission baud rate proportionally increases the transmission spectrum and can be used to convert unused spectrum into useable extra capacity.

With transmission flexibility, service providers can configure their client traffic with the following flexible options:

• 12×100 GbE or 3×400 GbE with 64 QAM modulation for DCI edge applications
• 8×100 GbE or 2×400 GbE with 16 QAM modulation for metro/regional and long haul
• 4×100 GbE or 1×400 GbE QPSK for the most challenging terrestrial and submarine networks

To ensure a smooth migration from 100GbE to 400GbE, it’s important to have a solution that can efficiently transport either type of traffic, or a combination of both, without restrictions on performance and functionality.

Increase Performance and Reach with 400GbE Long Haul

With 400GbE becoming the “common currency” for high-capacity Ethernet transmission, it’s important to have a solution that can support this traffic over long distances. For service providers supporting 400GbE traffic they can use Acacia’s Pico DSP-based solution and choose from various configurations, as previously mentioned, including the option to combine two 400GbE client signals into an 800G 150 GHz channel for transmission over their metro and long-haul networks.

Leveraging Acacia’s Pico DSP-based solution service providers can combine two 400GbE client signals into an 800G 150GHz channel for long haul transmission.

Migrating from 100G to Higher Speeds Just Got Easier

Multi-haul coherent solutions enable network operators to easily migrate from 100G traffic toward 400G and higher speeds to deploy new and exciting applications and services. Networks utilizing flexible coherent transmission can provide support for growing client traffic across the entire network—from DCI edge, metro, long-haul, and all the way to submarine. Learn more in this video.

Here are a few notable accomplishments from the past year.

The Rise of 400G Pluggables
Bandwidth demands have continued to grow, putting pressure on cloud providers to increase the data center interconnects (DCI) that link their facilities around the globe. This has helped to drive the emergence of new architectures that could support coherent transport in the same form factors as client optics, to satisfy those demands in a cost-effective and operationally efficient way. 400G pluggables were designed to be plugged directly into switches and routers, offering the same density for both coherent DWDM and client optics in the same chassis.

Utilizing our 3D siliconization technology, Acacia introduced a family of 400G pluggable solutions featuring an expansive list of interoperability modes (400ZR, OpenZR+, Open ROADM MSA and CableLabs Coherent Optics Physical Layer Specification). These solutions were designed to enable DCI and service provider network operators to address increasing bandwidth demand through a simplified network architecture, helping to reduce both capital and operational expenditures.

Modules based on multi-sourced 400ZR DSPs are now being validated for readiness in DCI applications and network operators are evaluating OpenZR+ solutions with enhanced functionality.  For example, Acacia and Inphi recently demonstrated interoperability of 400ZR over 120km. In addition, Acacia and NTT Electronics announced successful interoperability testing of 400ZR and OpenZR+. At Acacia, we believe we will see system vendors and network operators announcing trials in the near future.

Coherent Moves to Edge and Access
The benefits of coherent have already been demonstrated in the metro, long-haul and submarine markets, and with the coming of 5G and edge computing, the time is right for coherent optics to take the next step and migrate to edge and access networks. We believe this market can benefit from the scalability, operational simplicity and improved total cost of ownership that coherent has to offer.

To address the wide variety of requirements in the edge and access market, Acacia recently announced a portfolio of products, including a coherent bi-directional pluggable optical module for cable and 5G wireless X-haul applications, a 100G coherent point-to-point edge and access solution for 5G Wireless X-haul and Enterprise Services, and a 100G coherent DWDM module for cable/fiber deep and 5G wireless X-haul applications.

Multi-Haul Coherent Solutions Take Off
With bandwidth demands continuing to rise, network operators have been looking for solutions that improve efficiency and maximize capacity utilizing while reducing network cost.  Multi-haul solutions have emerged to meet the needs of many markets including cloud, metro, long-haul and submarine network applications by providing the high performance and flexibility features required to address meet these demanding applications.

Acacia’s AC1200 product family offers customers a multi-haul solution designed to cost-effectively improve network utilization in a wide range of network architectures. Supporting transmission speeds of up to 1.2 Tbps, the AC1200 utilizes Acacia’s 3D shaping technology designed to optimize fiber capacity and reach by filling gaps in margin and spectrum. In addition to its higher capacity and density, Acacia’s AC1200 product family, when embedded inside a number of our network equipment manufacturer partners’ products, provides features designed to enable network operators to improve efficiency while reducing network costs.

Here are a few examples.

Long-haul Terrestrial Applications
ADVA announced that the FSP3000 TeraFlex broke multiple industry records in live network trial. ADVA also announced that FUNET trialed ADVA FSP 3000 TeraFlex to dramatically expand network capacity and Serverius, one of the Netherlands’ largest data center service suppliers, is leveraging its FSP 3000 TeraFlex terminal to massively increase the capacity of its deployed infrastructure.

Submarine Applications
Cisco is making waves in the subsea market having demonstrated the benefits of the NCS 1004 over a subsea cable in production achieving record results. Cisco and Superloop announced two deployments of up to 400G for 4600km on the INDIGO West cable from Singapore to Australia, and the INDIGO Central cable from Perth to Sydney, featuring a two-fibre pair ‘open cable’ design with new spectrum sharing technology.

Oh What a Year – But the Show Must Go On
As NGON & DCI World and ECOC go virtual this year, I am looking forward to presenting in the following two panels. I hope to see many of you online and from all of us at Acacia…stay safe and healthy and have a great rest of the year.

• NGON & DCI World on Dec 1 at 9:00 am ET: “Next Generation Optics for Increased Capacity”
• ECOC Market Focus on Dec 7 at 17:00 CET: “A Path to Next Generation Coherent”

Contact us if you would like to schedule a meeting with myself or one of my colleagues.

The world’s leading annual submarine communications gathering – Submarine Networks World –  takes place this week virtually. Despite other communications networks being adopted, subsea networks still transport more than 99 percent of all intercontinental traffic.  The increase in the amount of people working from home in 2020, increases in e-commerce, more online digital platforms, and reliance on big data have all led to an increase in global bandwidth demand and a key factor driving the growth of the submarine cable system. There are currently hundreds of submarine fiber optic cables buried in oceans around the world stretching over approximately 750,000 miles that connect land cables from one continent to another. It’s these same cables that enable Submarine Networks World to be brought to you live into homes and offices this week. This cable map from TeleGeography provides a comprehensive view of each cable’s owner and endpoints.

Source: TeleGeography, Copyright © 2020 PriMetrica, Inc.

Submarine networks are critical pieces to the global flow of network data. While submarine cables were traditionally owned by telecom carriers, it’s been the content providers themselves, such as Google, Facebook, Microsoft and Amazon that have started investing in the build-out of new undersea cables in recent years to ensure they meet the internet bandwidth required for the cloud and streaming media services they provide. Key to meeting this demand is the use of fiber optics technology and advanced coherent transmission systems in both new and older cables.

Maximizing Transmission Capacity is Critical
Because it’s very expensive to build and lay undersea cables, maximizing transmission capacity is extremely important. However, a key challenge with submarine cables is overcoming chromatic dispersion and non-linear impairments which reduce capacity. In this video, Acacia’s Valeria Arlunno explains how using coherent optical communications technology overcomes this challenge.  As Valeria points out, to help maximize capacity and spectral efficiency, additional Digital Signal Processing (DSP) features are required. Continuous adjustment of the coherent modulation format and baud rate have enabled submarine network operators to improve the performance by finely tuning the balance between capacity and impairment penalty. In a submarine link, these fine-tuning capabilities are a key asset is maximizing the cable capacity using coherent optical transmission in either new or legacy fiber. These key capabilities are embodied in Acacia’s 3D shaping technologies in the Acacia Pico DSP.

Using Acacia’s AC1200 coherent module powered by Acacia’s Pico Digital Signal Processor (DSP), Acacia successfully transmitted the first 400G single carrier DWDM signal over the 6600km transatlantic Marea submarine Cable, achieving a spectral efficiency of 6.41 b/s/Hz.  Completed in 2017, this massive 10-million pound cable is located 17,000 feet under sea in some places, and runs between Virginia Beach, Virginia and Bilbao, Spain.

Cisco Makes Waves in Subsea Market
Acacia’s customer Cisco has announced multiple subsea trials and deployments with its NCS 1004 packet optical transport system that leverages Acacia’s AC1200 powered by Acacia’s Pico DSP chip including Cisco demonstrating 26.4Tbps on the MAREA transatlantic subsea cable.

In this blog, they discuss how they were able to demonstrate the benefits of the NCS 1004 over a subsea cable in production. The cable Cisco tested ran over 10,000km with accumulated chromatic dispersion of 210,000 ps/nm. This cable was designed as an open cable and had a ROADM line system already deployed with over 20 percent of the spectrum consumed by 200G channels from a current generation transponder. As part of the trial with the NCS 1004, Cisco tested 200G and 300G over different baud-rates across different parts of the spectrum.

With this test, Cisco’s solution achieved significant milestones. The NCS 1004 drove a single wavelength of 300G over a 10,000km sub-sea link. The spectral efficiency achieved was 43 percent better than any other option available in the industry today. As part of the testing, Cisco validated multiple combinations of bits per symbol and baud-rate for 200G line rate that provided granular control of spectral efficiency and Q-margin. This was demonstrated with the NCS 1004 operating as an alien wavelength over an existing third party SLTE platform running live traffic.

In addition, Cisco and Superloop announced two deployments of up to 400G for 4600km on the INDIGO West cable from Singapore to Australia, and the INDIGO Central cable from Perth to Sydney, featuring a two-fibre pair ‘open cable’ design with new spectrum sharing technology.

Connect with Us
Even though Submarine Network World will be virtual, we expect it to be an informative and interesting show – and we expect coherent technology to be a key topic to address growing bandwidth demand. To learn more about Acacia’s coherent optical solutions for submarine cable applications, contact us to set up a meeting.

Submarine cable networks are critical pieces to the global flow of network data. It is estimated that these cables carry 99 percent of all international communications traffic such as voice, data and video.  While submarine cables were traditionally owned by telecom carriers, it’s been the content providers themselves, such as Google, Facebook, Microsoft and Amazon that have started investing in the build-out of new undersea cables in recent years.  They are doing this to ensure they can meet the explosive demand for more internet bandwidth which is being driven by their services such as cloud and streaming media. Key to meeting this demand is the use of fiber optics technology and advanced coherent transmission systems in both new and older cables.

Fiber Optic Cables
The main advantage to fiber optic cables under the sea is that they allow large amounts of data to be transmitted very fast.  For example, if you want to stream a video, that video is converted to light so that it can be transported across a fiber optic cable.  Before it reaches its destination, it gets converted back to video.  While that process sounds simple, the technology behind it is amazingly complex and took years of development from optical component vendors, network equipment manufacturers, telecommunications carriers, and many others.

A good example of a fiber optic cable is MAREA, a 4,000 mile cable system built by Microsoft, Facebook and Telxius that crosses the Atlantic Ocean, connecting the United States to southern Europe. Completed in 2017, this massive 10-million pound cable is located 17,000 feet under sea in some places, and runs between Virginia Beach, Virginia and Bilbao, Spain. The MAREA cable features an open design and advanced coherent transmission system that allows it to evolve over time to enable the adoption of new technologies. Last December, the first 400G single carrier DWDM transmission was achieved on the 6,600 km Marea submarine cable.  This was significant because it demonstrated that improvements in capacity and spectral efficiency can enable increased utilization of deployed fiber and improved network capacity. To put into perspective how significant 400G transmission was on a submarine cable, think about the process of downloading all 8 seasons of Game of Thrones in high definition. Ten years ago using an optical cable at 10G, it would take about an entire day.  However, on a fiber optic cable running 400G, it would only take seconds to download. Higher speed is one of the reasons content service providers are so motivated to invest in the deployment of fiber optic cables in the ocean.

Another example of a content provider getting into the submarine cable business is Google, which has funded 13 submarine cables in the last ten years. Recently, Google completed a 6,214 mile subsea cable linking the coast of California to Chile. Named Curie, after the renowned Scientist Marie Curie, this cable was the first new cable to land in Chile in almost 20 years and is now the largest single data pipe connecting the country.  The growth of the cloud and internet services is driving the need for increased subsea network capacity and the content providers are setting themselves up for the future by investing in high-speed fiber links.

Future Undersea Developments
Many new fiber optic submarine cables are being installed to connect other parts of the world to the global internet backbone.  Every country wants to participate in the Internet revolution and with exciting new applications emerging such as 5G, the Internet of Things, machine learning, and self-driving cars, the need for higher bandwidth is growing.  Expanding subsea communications has the potential to connect our world like it’s never been connected before.