Dot-Cathode APD Receiver OEICs Achieving Sensitivity Gaps to the Quantum Limit Down to 10 dB

In this letter, we report experimental results of two ultra-sensitive direct detection optoelectronic integrated circuits (OEICs), realized in 180nm high-voltage CMOS. The receivers are comprised of a dot-cathode avalanche photodiode (APD), common-source integrate-and-dump front-end, and correlated double sampling (CDS) equalizer. At 200 Mb/s (100 Mb/s), bit error probability (BER) of 10−6, 642nm wavelength, and 50% return-to-zero on-off keying modulation the best measured sensitivity is −51.8dBm (−56.4 dBm), equal to a distance of just 12.1 dB (10.5 dB) to the quantum limit. At 100 Mb/s and a BER of 2 · 10−3, the gap to the quantum limit of 10 dB is achieved.