Study of Millimeter Wave Phase Shift in 40 GHz Hybrid Mode Locked Lasers

An investigation into using hybrid mode-locked lasers to implement millimeter wave phase shift is presented. The phase shift is measured directly using a vector network analyzer enabling straightforward characterization of such systems. Both magnitude and phase of the modulation response are measured and a ldquoplateaurdquo is observed in the magnitude response which corresponds to the locking range of the system. Phase shifts of greater than 90^deg are observed and such devices could have application in millimeter wave radio-over-fiber phased array antenna systems.