HIGH-SENSITIVITY DIRECT-DETECTION RECEIVER WITH A 1.5-MU-M OPTICAL PREAMPLIFIER

A 1. 5 optical preamplifier was used to improve the sensitivity of a PINFET receiver by 12 db. The resonant optical amplifier provided 17 db of fiber-to-fiber gain including coupling losses in an isolator and a narrowband optical filter. The achieved sensitivity, minus 45. 6 dbm at 500 Mbit/s, or 420 photons/bit, is the best reported for any direct-detection receiver and a factor of two better than previous results using optical amplifiers. However, the results are virtually identical to the best APD receiver results.