The infrastructure of data communications networks needs lots of fiber, semiconductors, and network equipment to bring data to the masses.
Optical data networks form the backbone of today’s communications. Data centers, which seem to dominate any discussion of digital communications, depend heavily on fiber-optic connections from a few meters to many kilometers. Getting those bits from here to there is an ongoing challenge because data rates are never fast enough.
Optical communications also play a major role in telecom networks. Wireless communications may get you as far as a tower and a microwave link may connect towers within a network but ultimately, the bits that represent voice and data must travel over fiber to reach a core network and then on to the recipient. With AI becoming a significant consumer of data, engineers developing everything from optical modules to semiconductors to network racks face new challenges.
At OFC 2024, EE World‘s editors walk the halls looking for the latest in optical communications. Here’s some of what we found.
We begin with Analog Photonics, a Boston-based company that’s not involved with data communications but rather with sensing. In this case, it’s optical sensing as opposed to RF sensing proposed for 6G wireless. In the video, we see optics used to detect people passing the Analog Photonics booth. Such sensing could find a place in driver-assistance systems or in driverless vehicles for detecting people or objects.
At the Huber+Suhner booth, the company exhibited connections for distributing GNSS timing throughout buildings. Using fiber means fewer antennas to connect to satellites. That translates into fewer possibilities for interference. A GNSS master clock must account for the added latency in fiber or copper in a distributed timing network.
Infinera’s large booth contained numerous optical networking products. Shown here is a member of the GX series modular platform. The G40 chassis accepts optical modules for long-haul transport. On the local side, it supports electrical links such as RJ-45 Ethernet. The G40 series comes in 300 mm and 600 mm widths.
Lessengers exhibited 400G QSFP112 SR4 and 800G QSFP112-DD SR8 optical transceivers built using the company’s direct optical wiring (DOW) technology. Lessengers CMO Taeyong Kim explained to EE World that the company uses a polymer optical strand to connect a laser light source such as a vertical-cavity surface-emitting laser (VCSEL) to an optical fiber. According to Kim, injection molding used to hold optical fibers isn’t precise enough for aligning fibers. Misalignment causes reflections and optical noise. To achieve the 400G and 800G speeds, a module uses eight or 16 polymer wires, respectively.
In the video below, we interviewed Adam Carter from OpenLight. Carter discussed the company’s IP for designing silicon photonics into ICs, which increases data throughput over electrical materials.
Networking equipment company Ribbon Communications exhibited its own optical module chassis, the Apollo series. The 9400 Series in the photo combines low power consumption with high-density to bring data rates of up to 1.2T using 100G and 400G links and with future 800G links. The platform supports combinations of eight single-slot or four double-slot blades.
EDA software publisher Synopsys showed engineers several designs developed using the company’s software. The photo shows a demonstration of transporting PCIe 6 signals over fiber through an electrical-optical-electrical interface at 128 Gb/sec. Why PCIe over fiber? It’s because of the distances between CPUs/GPUs for AI/ML, explained Priyank Shukla Product Manager, High-Speed SerDes IP Solutions. Such an ecosystem can send data distances of less than 2 km but surely, longer distances will arise. GPUs can be in the same or different racks. The PCIe link runs on top of Ethernet.
In the photo, the optical interface is on the purple board with an FPGA on the larger green board.
In a call with EE World following OFC, Jigesh Patel noted that once PCIe 7 is ratified, it will have tighter timing margins that PCIe 6. That will result in a need to simulate both electrical and optical parts of the link. He noted that the electrical link will be modeled as a low-pass filter and that there is no electrical analog for optics, particularly for wavelength polarization.
TE Connectivity showed several of its pluggable optical modules including OSFP, QSFP, QSFP-DD, SFP, and SFP-DD.
Did you attend OFC 2024? What did you think?
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