A 40-Gb/s integrated balanced optical front end and RZ-DPSK performance

We have designed and built an integrated balanced optical front end suitable for detecting RZ-DPSK transmissions when used with an external delay-interferometer. We have achieved an optically preamplified sensitivity of -35.7 dBm at a BER of 10 (-9) and an optical signal-to-noise ratio of 18.3 dB in a 0.1-nm bandwidth at 40 Gb/s. To the best of our knowledge, this is the first demonstration of 40-Gb/s RZ-DPSK reception with an integrated hybrid optical front end.