THz optical beat frequency generation from a single mode locked semiconductor laser

We demonstrate ultrahigh repetition rate beat signal generation by filtering two modes from the optical spectrum of a 110 GHz pulse train produced by a 1.56 μm wavelength, subharmonic hybrid mode locked monolithic semiconductor distributed Bragg reflector laser. The beat signal repetition rate can be tuned to any higher harmonic of the 110 GHz frequency up to 1.34 THz. Furthermore, the filtering technique facilitates low phase noise and synchronization with these signals.