Abstract

High sensitivity receivers are of interest because they allow considerable flexibility in the overall system design. Receiver sensitivity may be used to reduce the amount of transmitter power required, to extend the link distance of repeaterless links, to increase the amplifier spacing in an optically amplified link, or simply to provide additional margin. This paper reports the demonstration of high sensitivity 10 Gb/s receivers with two different modulation formats: on-off keying (OOK) and differential-phase-shift-keying (DPSK). Measured sensitivities at a bit-error-rate (BER) of 10-9 with a 231-1 length pseudo-random bit sequence (PRBS) are 76 photondbit (-40.1 dBm average received power) for the OOK receiver and 38 photons/bit (-43.1 dBm) for the DPSK receiver. These sensitivities represent considerable improvement over previously reported results [1,2], and are within 3.0 dB (OOK) and 2.8 dB (DPSK) of the ideal receiver sensitivities.[3,4]

© 1996 Optical Society of America