Forced SILPLL oscillation of X- and K-band frequency synthesized opto-electronic oscillators

A very clean and low phase noise microwave oscillator is required for communication and high resolution imaging. A frequency stabilized and tunable opto-electronic oscillator (OEO) is realized as synthesizer using a long fiber optic delay line combined with a tunable narrowband microwave filter. Forced oscillation using both self-injection locking and self-phase lock loop, as SILPLL provides an ultra-low close-in and far away from carrier phase noise to achieve a record low phase noise. A YIG microwave filter combined with an optically tuned transversal filter is employed to implement frequency tuned OEO to realize highly stable synthesizer in X-band. Phase noise - 136dBc/Hz at offset frequency 10kHz is achieved for 9GHZ to 11GHz. Moreover, a synthesizer for K-band is demonstrated by adjusting the operation point of a dual drive MZM (DD-MZM) from quadrature point of Vpi/2 to Vpi, where the second harmonic in addition to fundamental is efficiently generated with -127dBc/Hz phase noise at offset frequency 10kHz for 18-22GHz.