Laser-diode-based optoelectronic subharmonic phase-locked loop

An optoelectronic technique for synthesis of frequency-versatile electrical signals phase-locked to the optical clock is proposed. The key component is an integrated-optic modulator (IOM) operated in the nonlinear regime. With a photodetector, the IOM functions as an optoelectronic subharmonic mixer for intermixing microwave signals that are subharmonics of the optical clock. As a first demonstration, phase-locked subharmonics and fractional harmonics of the optical clock at f/sub 0/=500 MHz, with frequency equal to f/sub 0//n or (m/n)f/sub 0/, where n=3,3,4... and m/n=2/5,2/3,4/3,3/2 and 5/3, etc., are generated and characterized.<
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