Thursday, March 28, 2024

Coherent reports major advance in VCSELs

Coherent reported a  significant breakthrough in improving the bandwidth of its vertical-cavity surface-emitting laser (VCSEL), paving the way for use in next-generation optical interconnects that will operate at 200 Gbps per lane and thereby enabling optical transceivers with 1.6 Tbps capacity.

This improvement comes in the form of lithographic-aperture VCSELs, marking a significant departure from the oxide-aperture VCSELs that are the state-of-the-art VCSELs used in AI networks today. 

Oxide-aperture VCSELs are currently powering optical transceivers operating at 100G per lane data rates, including 800G (8x100G) multimode optical transceivers, but have reached their bandwidth limit of approximately 27 GHz. 

The new lithographic-aperture VCSELs feature exceedingly small apertures with high reproducibility and reliability. With this innovative design, it is feasible to achieve a device bandwidth of approximately 45 GHz, which, when combined with recent advances in digital signal processing technology, can pave the way to 1.6T (8x200G) multimode optical transceivers.

Multimode transceivers and links are ideally suited for short-reach connectivity in data centers, spanning artificial intelligence (AI), high-performance computing (HPC), and networking applications.

A technical paper describing this leap in performance was presented by Dr. Stefano Tirelli,  Senior Manager, VCSEL Technology, at OFC 2024.

“As a leading supplier of VCSELs for multimode 800G optical transceivers, we are pleased to extend our technological leadership on our roadmap toward next-generation 200G VCSELs,” said Chair and CEO Dr. Vincent D. (“Chuck”) Mattera, Jr. “The development of a reliable, lithographic-aperture VCSEL is a step in the right direction. While we have more work to do, we are very pleased with the progress we have made so far.”

Keysight bids for Spirent, topping Viavi’s offer

 Keysight Technologies announced its intention to acquire the entire issued and to be issued share capital of Spirent Communications PLC for a cash consideration of 199 pence per Spirent share, which values Spirent at approximately £1,158 million (US$ $1,463 million1), on a fully diluted basis. Spirent shareholders will also be entitled to receive a special dividend of 2.5 pence per Spirent share, in lieu of any final dividend for the year ended 31 December 2023 (together with the cash consideration of 199 pence per share, the “Offer”).

Spirent’s board of directors intend to unanimously recommend the Offer which is conditional on, among other things, the approval of the requisite majority of Spirent Shareholders at the Court Meeting and the Spirent General Meeting, as well as regulatory approval as laid out in the Offer announcement.

Keysight said it views Spirent’s business as highly attractive and aligned with Keysight’s long-term software-centric solutions strategy. Keysight believes there is strategic synergy between the two businesses, and that the parties’ respective complementary products will help customers address their complex engineering challenges. 

Commenting on the acquisition, Satish Dhanasekaran, President & Chief Executive Officer of Keysight, said: “Spirent has a differentiated portfolio, which is a strong fit for Keysight. Both companies share a common focus on empowering and accelerating high-value solutions for customers. In Keysight, Spirent will join a platform of significant customer scale with the capacity to provide the necessary capital and resources to help Spirent grow and accelerate the delivery of its strategic vision. Keysight’s long-term customer relationships, industry expertise and global reach will help Spirent drive product development and execute on its full potential. With similar cultures valuing customer-centricity and high-performance, we believe that Keysight will be an excellent home for Spirent to thrive and deliver sustainable, long-term growth. Our superior Offer recognizes the value of Spirent’s achievements to-date, and the exciting prospects of the combination of our complementary product portfolios to provide end-to-end solutions for customers across their lifecycle needs.”

Viavi to acquire Spirent, consolidating test & measurement companies

VIAVI Solutions agreed to acquire Spirent Communications, a global provider of automated test and assurance solutions for networks, cybersecurity, and positioning, for approximately £1,005 million or $1,277 million, based on the exchange rate on March 4, 2024.In addition, Silver Lake is making a US$400 million long-term strategic investment in Viavi in connection with the acquisition. Viavi said it believes that acquiring Spirent will significantly...

Lumentum enhances its 800ZR+

Lumentum announced significant performance enhancements to its 800ZR+ transceivers. These improvements enable the 800ZR+ modules to serve a wider range of applications, including expanded use in metro and regional networks through the ability to interface directly into routers. Additionally, the enhanced performance modes now make 400ZR+ and 600ZR+ operation suitable for true long-haul applications, with OSNR and dispersion tolerance enabling reaches exceeding 2000 km at 400 Gbps. 

Lumentum has optimized its latest generation of 800ZR+ modules to maximize performance, while maintaining a compact QSFP-DD and OSFP form factor. These modules employ Lumentum’s latest hybrid photonic integrated circuit technology, which incorporates both the company’s leading edge indium phosphide photonic integrated circuits and silicon photonics. The performance and use case flexibility provided by these modules mark a significant step in the evolution of high-speed communications networks.

“Lumentum's unique photonic component capabilities and innovative module designs, together with our partners' latest generation coherent DSPs, enable us to provide solutions that dramatically increase scalability for both cloud and telecom network operators,” said Wupen Yuen, President of Cloud and Networking at Lumentum. “Our advancements also help address the challenges of scaling data center interconnects for the bandwidth needs related to artificial intelligence and machine learning."

These modules are currently available for sampling.

Credo and Wistron demo 800G Linear Receive Optics

Credo hosted a demonstration of Linear Receive Optics (LRO), using its Credo Dove 850 DSP, along with the 51.2 Tbps Wistron DS-6183-64O 64-port 800GbE switch. 

In an LRO transceiver, or Active Optical Cable (AOC), only the transmit path from the electrical input to the optical line side output includes a DSP for signal retiming and equalization. 

All three 800G OSFP LRO modules provided by Credo partners for this demonstration seamlessly “plug and play” with the 51.2T Wistron switch, a tremendous benefit in mass deployment.

The Dove 850 is a unidirectional 8 x 112 Gb/s DSP purpose built for the LRO architecture. The Dove 850 DSP aims to address the inherent weakness of a Linear Pluggable Optics (LPO) implementation by facilitating IEEE compliant optical transmit signaling and easing the deployment burden on system operators by eliminating manual, per port tuning. The result is lower bit error rates, enhanced sensitivity, reduced performance variation, and improved resilience to different switch ASICs, PCB traces, optical components, and environmental conditions. Dove 850 allows transceiver vendors to optimize module cost by employing a variety of optics, including VCSELs, silicon photonics, EML or thin-film lithium niobate as dictated by the application requirements.

Wistron’s DS-6183-64O is a compact 2RU 64 port 800G OSFP Ethernet Switch, built with Broadcom Tomahawk 5 chip, providing high bandwidth, high throughput, and reliable solutions. Support up to 102.4Tbps of switching I/O bandwidth and non-blocking switching fabric, delivering wire-speed L2 and L3 packet forwarding capabilities on all ports for Low-latency data transmission and support for state-of-the-art instrumentation feature. With the advanced system integration technique, all OSFP ports on DS-6183-64O support up to 800GbE and can be configured as 2 x 400GbE and also support 18W output. For long-range DCI application, 8 OSFP ports of DS-6183-64O could even support 25W in each port. DS-6183-64O is loaded with ONIE (Open Network Install Environment), which supports the installation of compatible NOS (Network Operating System) software, like SONiC.

“Linear Receive Optics are pushing the industry forward. Credo is streamlining implementation for module vendors while addressing the need for improved energy efficiency across the data center,” said Anderson Chiu, General Manager of Networking Development, Enterprise and Networking Business Group of Wistron. 

Coherent samples bi-di circulator adaptor

Coherent introduced a bi-di circulator adaptor that enables bi-directional transmission over a single fiber between two transceivers. By enabling bi-directional transmission, the fiber count is reduced by a factor of two, which allows significant cost and space savings.

The Coherent bi-di circulator adaptor is a completely passive device, compatible with all transceiver LC connector ports, offering low insertion loss as well as high directivity in a compact footprint. It is available in O-band, C-band, and L-band versions, and customized designs can be considered as well.

“The urgent demand for improved utilization of the fiber plant with markets as diverse as AI/ML applications within the data center and the broadband access market shows the real need for simple, cost-effective solutions like our bi-di adaptor. By combining our fully vertically integrated supply chain, including the core garnet chips, with our fully automated assembly process, we can deliver a high-volume solution that brings significant value to our customers,” said Dr. Beck Mason, Executive Vice President, Telecommunications.

Dell'Oro: Telecom Capex Declined in 2023


Preliminary findings show that worldwide telecom capex, the sum of wireless and wireline/other telecom carrier investments, declined for the full year 2023 in nominal USD terms, recording the first contraction since 2017, according to a recent report from Dell'Oro Group. This deceleration in the broader capex spend is consistent with the aggregate telco equipment slump previously communicated for the six Dell'Oro telecom programs (Broadband Access, Microwave Transmission & Mobile Backhaul, Optical Transport, Mobile Core Network, Radio Access Network, Service Provider Routers & Switch).

"The fundamental challenges have not changed. Operators have a fixed capital intensity budget and capex is largely constrained by the revenue trajectory," said Stefan Pongratz, Vice President and analyst with Dell'Oro Group. "What is complicating the situation is that the revenue pie remains fixed. Following some positive developments amidst the peak of the Covid-19 pandemic, our analysis shows that operator revenue growth slowed in 2023 and has more or less remained stagnant over the past decade. And based on the guidance, operators, in general, are not overly optimistic that emerging opportunities with generative AI, edge computing, enterprise 5G, FWA, and 5G-Advanced will expand the pie," continued Pongratz.

Additional highlights from the March 2024 Telecom Capex report:

  • Global carrier revenues are expected to increase at a 1 percent CAGR over the next 3 years.
  • Market conditions are expected to remain challenging in 2024. Worldwide telecom capex is now projected to decline at a mid-single-digit rate in 2024 and at a negative 2 to 3 percent CAGR by 2026.
  • The mix between wireless and wireline remains largely unchanged, reflecting challenging times still ahead for wireless. Wireless related capex is on track to decline at a double-digit rate in the US in 2024.
  • 5G era capital intensity ratios peaked in 2022 and are on track to approach 15 percent by 2026, down from 18 percent in 2022.

TRUMPF demos 100G VCSEL for 800G transceiver

 TRUMPF Photonic Components demonstrated 100Gbps VCSEL performance in an 800G tranceiver by Optomind. 

TRUMPF argues that for interconnect distances of up to 100 meters, VCSELs are the best solution in terms of power, cost and the productivity of SR modules. TRUMPF is offering both VCSELs and photodiodes as a matching pair solution, in singlets, 1x4 arrays and 1x12 arrays for 14G and 25G for the NRZ applications. The same is offered for 56G PAM4 applications. The VCSELs are specifically designed and implemented to meet the requirements of hyperscale data centers including for AI/ML applications, high-performance computing systems, and other bandwidth-intensive applications, as they deliver high performance and reliable data transmission at high speeds.

“We are delighted to have achieved a performance of 800Gbps in our transceiver leveraging innovative optics technology and TRUMPF’s VCSEL” commented Yung Son, Chief Marketing Officer of Optomind. “We look forward to solidifying our partnership with TRUMPF as the strategic best-in-class VCSEL supplier for distinguished transceiver and active optical cable (AOC) to our customers,” he added.

“We are pleased to have collaborated with Optomind to demonstrate the performance of our VCSEL at PAM4 112Gbps/ch in their transceiver, which validates the use of it in a real-world application,” says Ralph Gudde, Vice President of Marketing and Sales at TRUMPF Photonic Components. “A full-featured version of our 100G VCSEL is planned for production release this summer. TRUMPF is diversified, has a strong technology background and brings solid long-term commitment as a technology partner and a key supplier into the datacom business.” he explained.

MaxLinear announces “Rushmore” 200G/lane PAM4 DSPs

Building on its Keystone family of 5nm 100G/lane DSPs, MaxLinear announced the development of its fourth generation 200G/lane PAM4 SERDES (Serializer/Deserializer) and DSP family, Rushmore. 

The Rushmore family encompasses a diverse array of variants tailored to meet the evolving needs of modern data centers and telecommunications networks. This includes support for fully re-timed optical modules, half re-timed optics, and active electrical cables (AECs). Moreover, MaxLinear is introducing both 8x200G-to-8x200G re-timers and 8x100G-to-4x200G gearbox variants, providing customers with a comprehensive suite of solutions to address their specific requirements.

The devices will be produced by Samsung Foundry using its leading-edge-CMOS-based process.

“The AI/ML revolution has accelerated the pace of innovation across the industry, and that is also the case at MaxLinear,” said Drew Guckenberger, Vice President of High Speed Interconnect at MaxLinear. “Starting from our highly successful Keystone 5nm 100G/lane DSP family, the amount of additional innovation that has gone into the new Rushmore 200G/lane DSP family is incredible. The impacts on power and performance our partners will see are expected to be significant for the industry as a whole as we scale into the new AI/ML world.”

OE Solutions extends its transceiver portfolio

OE Solutions introduced two new Digital Coherent Optical (DCO) transceiver modules for applications in access networks. Both are available with optional EDFA booster amplifier and tunable optical filter.

  • Reduced-power 100G QSFP28 DCO transceiver -- a result of OE Solutions’ continued focus on reducing the power consumption of coherent transceivers for access applications. Current improvements to the designs enable a device with a maximum power consumption below 10W allowing the transceivers to be used in more network elements.  The 100G QSFP28 DCO without booster amplifier exhibits a power consumption of less than 10W. It will sample in May of this year and be generally available in June. 
  • 400ZR QSFP-DD DCO -- available with or without EDFA booster amplifier and tunable optical filter, is the first product in a series of 400G DCO transceivers that will include also ZR+ and OpenROADM variants in the future. The 400ZR device leverages 60GB components and 16-QAM encoding. Samples of the 400ZR QSFP-DD DCO transceiver will be available in August, and generally availability will be in October of this year.

“We are excited about this enhancement of our DCO portfolio giving our customer additional options for optimizing access networks to accommodate the growing bandwidth needs at the edge of the network”, said Walter Lee, Vice President and General Manager of the Optical Transceiver Business Unit. He continued, “We will continue to focus our development on coherent transceiver variants targeting the particular needs of access networks with their broad range of requirements and deployment environments”.

MACOM demos 100G/Lane Switch to Server Link with LPO

MACOM is demonstrating switch-to-server interoperability of its linear drive 100G per lane components:

  • MACOM PURE DRIVE Transimpedance Amplifiers and Laser Drivers
  • Broadcom’s BCM57608 Series Ethernet Network Interface Card (“NIC”)
  • Broadcom’s Tomahawk 5 Ethernet Switch Chip

The switch-to-server link represents an important use case for the linear drive architecture, which can provide an optimized interconnect solution for Cloud infrastructure. Linear drive modules eliminate the Digital Signal Processor (DSP) from pluggable optical modules enabling lower power consumption, improving signal latency and reducing cost.

“Due to linear drive’s benefits, the demand for linear pluggable optical (LPO) modules with MACOM PURE DRIVE technology is expanding. We are pleased to demonstrate a working example of 100G/lane switch-to-server connectivity leveraging this technology,” said Ryan Latchman, Vice President, High-Performance Connectivity Product Marketing, MACOM.