Integrated Optical Beamforming Network for Millimeter Wave Communications

An optical ring resonator (ORR) based 1 x 4 integrated optical beamforming network (OBFN) targeting mmW is reported. The optimized true time delay response of a 3-ORR delay line with a bandwidth of 8.7 GHz was achieved over tuning range of 172.4 ps, which corresponds to a 31 pi phase shift for a 90 GHz signal. A 3 Gbps OOK NRZ data signal was transmitted through the delay line to verify the overall performance. A 49 degrees beamsteering angle equivalent OBFN delay response was achieved for a 90 GHz half-wavelength dipole antenna array. Using heterodyne upconversion technology and a single delay path, 41 GHz mmW signal with 3 Gbps OOK NRZ data modulation was generated and delayed.