A millimetre wave phase shifter using a 40GHz hybrid mode locked laser

In this paper, electrical injection locking of a mode-locked laser is used to create a millimetre wave phase shifter. 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 for sufficiently high RF input power a ldquoplateaurdquo is observed in the magnitude response which corresponds to the locking range of the system. Phase shifts of greater than 90deg are observed and such devices could have applications in millimetre wave radio-over-fibre phased array antenna systems.