Tech focus: high-capacity optics

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A glance at the current market for fifth-generation coherent optics, and some of the latest developments available

Before the pandemic began, all eyes were on high-capacity, fifth-generation coherent optics as one of the biggest trends to shape the industry, with expected demonstrations at all of the key industry events.

Coherent optical transmission uses modulation of the amplitude, phase of the light and transmission across two polarisations in order to increase the amount of information transported along the fibre cable. It uses digital signal processing (DSP) at transmitter and receiver level and can offer higher bit-rates, as well as better flexibility.

The popularity of coherent optics has increased in the last few years thanks to their ability to address capacity issues. While the global situation prevented much of the interaction and face-to-face views of this technology, it did not stop its development, and there have been a number of trials and demonstrations from vendors and operators alike, highlighting the achievements of higher wavelengths, such as 600 and 800G.

Featured product: Infinera

The GX Compact Modular Series, powered by Infinera’s ICE6 800G optical engine, offers superior optical performance and scalable connectivity in a compact, flexible package. Its modular sled-based architecture with integrated optical line system capabilities enables optimised support for numerous network applications.

The GX Series offers leading programmability and performance, with support for up to 800G per wavelength along with feature-packed automation. It supports deployments over virtually any optical line system and allows operators to save on CapEx and OpEx with industry-leading power consumption and a pay-as-you-grow modular design.

ICE6 enables network operators to meet the demands of rapid bandwidth growth by providing the greatest capacity at the greatest reach, resulting in a solution with the lowest cost and power per bit and the highest spectral efficiency possible. ICE6 Turbo is a performance-optimized configuration of Infinera's industry-leading 1.6T ICE6 coherent optical engine that further boosts performance by up to 30% for high-speed applications.

www.infinera.com 

Laser Components: Featured product

Amplitude Optical Modulators O, C & L Bands: Digital and Analogue

Lithium niobate (LiNbO3) intensity modulators are designed for modulation frequencies larger than 30GHz.  The X-cut design of the Mach-Zehnder modulators provides an unmatched stability in a wide range of operational conditions plus zero chirp performance.  iXblue’s proprietary waveguide design offers low insertion loss with a high contrast.

Key features include low insertion loss, high bandwidth, zero chirp, low driving voltage and high-second harmonic rejection. Applications include digital modulation NRZ, RZ, DPSK, duo binary modulation formats, up to 44Gb/s-NRZ, QPSK-56Gb/s and analogue modulation up to 40GHz. Matching modulator digital driver amplifiers are DR-DG and the DR-AN family for analogue applications. The DR-DG drivers are optimised for peak-to-peak voltage, rise/fall times and jitter and the DR-AN is characterised by a low noise figure and a linear transfer function with optimised 1dB compression point.  The driver exhibits flat group delay and gain curves with reduced ripple over the bandwidth.

Further information: https://www.lasercomponents.com/uk/product/fiber-optical-modulators/

Commercial products

Vendors of high-capacity optical engines, modules and supporting products include Adva, now part of Adtran. Its TeraFlex CoreChannel ensures 800Gb/s transport with high efficiency, high performance and low cost, achieving distances more than 50% longer than 95GBd-based solutions. Its adaptive baud rate ensures that the minimal amount of spectrum is used. This is low when conditions allow. However, the CoreChannel sled’s 140Gbd sub-carrier technology gives it the option to harness ultra-high baud rates and carry up to 800Gbit/s further.

Broadcom’s recent launch in this field is the StrataXGS Tomahawk 5 switch series, providing 51.2 Tb/s of Ethernet switching capacity in a single, monolithic device. It enables the next generation of unified data centre infrastructure with 64 ports of 800GbE switching and routing. Virtualisation of general compute and AI/ML workloads is possible with single-pass VxLAN routing and bridging.

Ciena’s WaveLogic 5 Extreme (WL5e) coherent optical technology  is designed to support up to 800Gb/s capacity per channel across terrestrial and submarine applications. It provides programmable capacity in 50G increments over a single-wavelength 800G solution and enables an evolution to emerging 400GbE-interface routers, with the ability to efficiently transport 400GbE client rates at any distance, from across the metro to across the ocean.

Cisco recently announced 400 and 800GbE options in its Nexus line. These include the Nexus 9800 and Nexus 9400 chassis switches, as well as two new Nexus 9300 fixed switches all with support for 100GbE and 400GbE for next-generation networks. Also available is a new chassis switch designed for 100GbE/ 400GbE today and 800GbE in the future. Ranging in capacities from 57Tb/s to 115Tb/s, the Nexus 9800 series can either take four or eight line cards, two supervisor modules, and two or three power supply trays per chassis.

Hengtong Rockley Technology offers 800G QSFP-DD800 DR8 optical modules, based on EML technology. The company adapted 7nm DSPs with built-in drivers, and COB structure to achieve this 800G QSFP-DD800 DR8 design. The total module power consumption is around 16W.

Huawei’s 800G module is designed to help operators cope with the bandwidth challenges of 5G networks. Amongst its features, line rates can be tuned from 200 to 800Gb/s, making it adaptable to various applications and enabling smooth evolution over the next 10 years. Multiple application scenarios include backbone and metro transmission, as well as data centre interconnections.

The sixth-generation Infinite Capacity Engine (ICE6), from Infinera’s Advanced Coherent Optical Engines and Subsystems, is a 1.6Tb/s optical engine that delivers two independently programmable wavelengths at up to 800Gb/s each. Using a 7-nm CMOS process node DSP and advanced PIC technology, ICE6 leverages ultra-high baud rates, high modem SNR, and innovative features to break performance and spectral efficiency barriers, including 800G single-wavelength performance over 1000+ km in a commercial network.

InnoLight’s 800G OSFP optical module includes two architecture solutions, 4x100Gx2 and 8X100G. In addition to the traditional EML design, it also adopts silicon-based solution to meet short-distance transmission needs. The products of this series comply with IEE802.3ck and OSFP MSA standards, and support CMIS4.0. Products are mainly used in 800G Ethernet, data centres and cloud networks.

Lumentum offers a suite of 100 to 800Gb/s optical components to customers looking for coherent products. The company's portfolio provides performance-optimised discrete components, narrow linewidth lasers, high-baud rate coherent modulators and receivers, as well as integrated components for QSFP-DD, OSFP, CFP2, and other small-form-factor pluggable coherent transceivers.

Source Photonics’ 800G PAM4 OSFP/QSFP-DD800 optical transceivers incorporates the in-house vertically integrated 53G EML laser chips and the state-of-the-art 7nm 800G DSP chip for lowest power consumption. It provides various optical fibre connector choices, a smooth transition from single-to-dual port 400G optics in the 800G form factor that requires backward compatibility with the large instalment base of fibre plants.

Viavi offers test and measurement solutions for 800G. The ONT 800G FLEX XPM module is the an integrated test solution with a native 800G interface based on 100G electrical lane speed. It supports multiple pluggable form factors including the OSFP 800G and 800G QSFP DD. The ONT 800G FLEX V2 module, along with the ONT DCO and Ethernet modules, provides automated optical transport test features through a 2 x 400G interface. The company’s ONT-800 optical network tester is a rack-mountable, high-performance mainframe that establishes a sturdy foundation for the ONT family of swappable test modules.

This is not an exhaustive list, if you provide high-capacity optical engines, modules and supporting products and would like to be included, please get in touch.