Frequency multiplication of microwave signals by sideband optical injection locking using a monolithic dual-wavelength DFB laser device

Frequency multiplication of a microwave signal was achieved by modulating one arm of a dual-wavelength distibuted-feedback (DFB) laser device and injection locking the other arm of the device on one of the modulation sidebands, The dual-wavelength laser consists of two DFB lasers integrated with a Y-junction combiner on the same semiconductor substrate, thus making a compact device (L = 500 mu m) The output of the combiner was allowed to beat on a high-speed photodetector, The resulting microwave signal had a narrow line shape superimposed on a Lorentzian pedestal and was at a multiple of the modulating radio frequency. Three regimes of operation of the laser device were also observed: chaotic, self-pulsating, and heterodyne.