Experimental demonstration of a photonic phase locked loop

The paper concerns experimental validation of a photonic phase locked loop linear phase demodulator employing a novel attenuating counter propagating in-loop phase modulator (ACP-PPLL). The ACP in-loop phase modulator is free of propagation delay allowing stable operation of the PPLL with large gain. An ACP-PPLL with a bandwidth of 100MHz was implemented for the first time. Highly linear optical phase demodulation was observed. With 550mW optical input, the measured spurious free dynamic range (SFDR) is 134dB·Hz2/3 at 100 MHz. With higher optical input, the SFDR was pushed to 135dB·Hz2/3 at 200 MHz.