Ring resonator based integrated optical beam forming network with true time delay for mmW communications

An optical ring resonator (ORR) based integrated optical beamforming network (OBFN) for a W-band millimeter wave phased array antenna is reported. The delay response of a 3-ORR delay line is optimized and dynamic tuning ranges of 208.7 ps and 172.4 ps for the true time delay bandwidths of 6.3 GHz and 8.7 GHz are achieved. Moreover, all of the delay paths are successfully tuned with 4. 2 ps delay difference from the neighboring paths. Eye diagrams of a 3 Gbps NRZ OOK modulated signal are measured to show that no noticeable signal deterioration is induced by the OBFN chip.