A monolithic optical heterodyne source based on dual DFB lasers using an InP generic foundry platform

A photonic integrated circuit developed in a generic foundry platform for continuously tunable microwave generation is presented. On this chip, two single-wavelength DFB laser diodes generate a two-tone emission through one optical waveguide coupler as combiner. The two-tone emission spectrum with >50-dB suppression ratio exhibits a continuous wavelength offset tunability up to ~4.3 nm, corresponding to 0.55-THz. With an external photodiode, a RF beat note at 10 GHz is experimentally demonstrated.