Computation of Bit-Error Rate of Various Heterodyne and Coherent-Type Optical Communication Schemes

TLDR: The computation of the minimum signal level for achieving a prescribed bit-error rate in various heterodyne and coherent-type optical communication systems, as functions of the information-transmission rate and mixerdiode parameters is presented.

Abstract: The receiver sensitivity in optical communication is improved by heterodyne and/or coherent communication schemes, as compared with an ordinary intensity-modulation/direct-detection system. This paper presents the computation of the minimum signal level for achieving a prescribed bit-error rate in various heterodyne and coherent-type optical communication systems, as functions of the information-transmission rate and mixerdiode parameters. It is shown that in long-wavelength (1.3 um ~ 1.6 urn) region, the improvement in the signal level by the heterodyne/coherent schemes is relatively high (10 dB-20 dB). improvement of the receiver sensitivity especially at the longer wavelengths, because these schemes bring forth a sensitivity close to the shot-noise limit, regardless the mixer-noise performance [1]. The improvement of the sensitivity by these schemes was first computed by Yamamoto [2], who gave the BER vs. signal-power relations for various heterodyne/coherent schemes.