Bandwidth demands continue to rise and with the move from 100G Ethernet to 400G, the design of optical transceivers is getting more complex. Currently, 400G QSFP-DD transceivers use 400GAUI-8 solution, which utilizes 7nm DSP (Digital Signal Processor) as gearbox/retimer for PAM4 signal. The signal analysis and processes are performed in the digital domain.
In the last couple of years, our partner Optomind, Korea with Open Eye Consortium has been doing some exciting work on analog CDR based AOCs. The Open Eye approach replaces the digital signal processor (DSP) based architecture common in current designs with one that leverages analog clock and data recovery (CDR) devices. The use of analog CDRs instead of DSPs result in significant cost, latency, and power benefits and simplified manufacturing.
The superior design of Optomind’s DSP-free 400G QSFP-DD AOCs allows for lower crosstalk between channels. In-house designed optical couplers negate ferrule alignment requirements, increasing coupling efficiency and suppressing noise, resulting in unmatched performance. For applications like high-speed computing, 400G DSP-free AOCs offer the added benefit of 100ns lower latency than conventional DSP based AOCs.
- Lower power consumption – 7.5W per cable end with all CDRs enabled. Compare this to 10W per end of DSP-based AOCs and you can get a sense of the power savings from switching over to analog CDR based AOCs.
- Lower latency – Only 20ns, 100ns lower than DSP based AOCs. Latency is a very important parameter for finance, gaming and supercomputing applications
- Impressive BER performance – 1×10-15 (with FEC)
- Longer transmission – 70m with OM3, 100m with OM4 cable
- CMIS 4.0 compliant