Phase-noise-insensitive coherent optical heterodyne CPFSK receiver with limiter-discriminator detector

A coherent optical heterodyne CPFSK receiver with a limiter-discriminator (LD) detector, which cannot be degraded by quantum phase noise of lasers when the frequency deviation ratio h is equal to 1, is proposed. The receiver can give the same bit error rate as the ideal digital DPSK system. In addition, 1/2 exp (-SNR) can be considered as the upper bound of the minimum error rate of the CPFSK-LD detector.<
>