Direct Demodulation and Channel Filtering of Phase-Modulated Signals Using an Injection-Locked VCSEL

Detection of phase-modulated optical signals without the use of an externally generated local oscillator is demonstrated using an injection-locked vertical-cavity surface-emitting laser. When it is used in a multichannel system, this technique is also capable of actively filtering out one of the phase-modulated optical carriers. The experimental results of the proposed receiver performance in a three-channel optical system are presented here. A signal-to-noise ratio of 75 dBc/Hz is obtained