This year’s OFC in San Francisco featured one thing, or so it seemed: 1.6T. Every company making optical modules was showing them lest they be left behind in the always accelerating data rate race. As with any emerging technology, test equipment must lead the way. After all, how do you know if anything works unless you test it?
To achieve 12.6T speeds over optical fiber, you need multiple lanes of traffic. As of today, the best we can do over copper differential pairs is 224 Gb/sec. That means you need eight such lanes to multiplex into 1.6T. But, the people building an operating data centers want fewer lanes and they are already asking for 3.2T while just now deploying 400G and 800G links. Hence, we’re starting to see 448 Gb/sec lanes emerging. The test equipment needed for 448G/lane is getting closer but for now, testing is focusing on 800G and 1.6T over four and eight lanes.
Anritsu hosted several optical measurement test setups. Pictured is a setup featuring the company’s Vectorstar ME7848A Opto-electronic Network Analyzer. Operating at 850 nm, 1310 nm, and 1550 nm wavelengths, the ME7848A lets engineers characterize electrical-to-optical, optical-to-electrical, and optical-to-optical and their components for error-corrected transfer function, group delay, and return loss measurements of E/O and O/E components and subsystems. An internal vector-network analyzer (VNA) streamlines de-embedding for calibration.
Bristol Instruments appeared at OFC with its 438A wavelength meter. Covering 1000 nm to 1680 nm and operating with CW or modulated signals, the 438A provides measurement accuracy of ±0.3 pm.
The EXFO booth included many benchtop and handheld optical test equipment. The photo shows the BA-4000 Bit Analyzer, which performs bit-error-rate (BER) measurements on optical links up to 800 Gb/sec (800G). It supports NRZ and PAM4 modulation, performing tests using pseudorandom bit sequences (PRBS) 7/9/11/13/15/23/31/13Q/31Q, and SSPRQ test patterns.
Keysight Technologies had a booth outside the exhibit hall and you couldn’t miss it as you came down the escalator. The video shows a demonstration of a 448 Gb/sec link. At this point, 448G transmissions are simply unstructured bit streams but this demonstration shows what’s possible. The 800G and 1.6T products shown at OFC are currently using four or eight 224 Gb/sec per lane but as always, people want 1.6T using four lanes, not eight.
The photo shows a 1.6T optical module connected to a Keysight DCA-M sampling oscilloscope. Indeed, several optical module demos at OFC were using the DCA-M.
Multilane exhibited its BER testers. Shown here is the ML4079EN. It lets you measure BER at data rates up to 800G using 8×100G per lane. Test patterns include PRBS7/9/11/13/15/16/23/31/58, PRBS13Q, PRBS31Q, SSPRQ, and square wave. It supports 18.5-29 and 37-61 Gbaud PAM4 or NRZ modulation, reaching 112 Gb/sec with PAM4.
OZ Optics exhibited its fiber length meter, model OFLM-2000, which can measure fiber lengths from a few millimeters to 500 m. Applications include optical fiber cable assemblies, field installations, production test, and fiber laser manufacturing.
Spirent Communications Demonstrated its TestCenter equipment for testing Ethernet optical modules at speeds from 100G to 800G, shown in the rack photo.
Viavi Solutions exhibited its bench, lab, and field optical test equipment. The One Lab Pro (shown) tests optical Ethernet at speeds of 800G and 1.6T. One Lab Pro consists of a controller and up to 16 test modules, each supporting up to eight ports. Use it to test chips, pluggable modules, and network equipment such as switches for protocol layers 2 and 3.
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