FIBER OPTIC SUBCARRIER TRANSMISSION-SYSTEMS USING COHERENCE MULTIPLEXING TECHNIQUES FOR BROAD-BAND DISTRIBUTION NETWORKS

Fiber optic subcarrier transmission system using coherence multiplexin g techniques for broad-band distribution networks is proposed. This sy stem makes it possible to improve the laser linewidth requirement and also to eliminate the effect of intermodulation distortion (IMD) which is serious problem in subcarrier multiplexed (SCM) system. In the pro posed system, the frequency difference, f(0), between the reference li ght and the signal light makes it possible to generate the broadband F M signal after photodetecting. Thus, an increase in the modulation ind ex provides a corresponding increase in receiver sensitivity. We analy ze the fundamental performance of the proposed system and derive the s ignal-to-noise ratio (SNR) at the output of FM demodulator by taking t he threshold effect and spike noise into account. The proposed system can achieve the total capacity in excess of 10 GHz, and thus it is att ractive for multichannel broad-band distribution networks.