Analysis of the Optical Limiter-Discriminator Demodulating the Optical FM-SCM Signals

This paper analyzes the demodulation performance of an optical limiter-discriminator, in response to an optical FM-SCM signal. The carrier-to-noise power ratio (CNR) as well as composite second order (CSO) and composite triple beat (CTB) distortions have been calculated at the output of the optical limiter-discriminator. The analysis predicts that to achieve a CTB level of less than -39 dB with the constituent laser diode power of 1 mW each, the effective optical FM index should be less than (.03) for 100 subcarrier channels. The system can operate with a low level of received optical power. The proposed limiter-discriminator meets the requirement of a FM CATV receiver.