Abstract

The development of low-loss single-mode fibers near 1.6μm, where the available photodetectors exhibit poor performance, makes specific features of coherent detection very attractive; the quantum detection limit can be achieved and laser amplifiers could be efficiently used because of the amplified spontaneous emission rejection by the coherent detection process. The best improvements as compared with incoherent intensity modulation systems are obtained with PCM-PSK and PCM-FSK coherent detection with a reduction of more than 10 dB of the required minimum optical power to achieve the same bit error rate (typically 10⁻⁹).⁻³

© 1982 Optical Society of America