Photonic Crystal Fiber Beamformer for Multiple $X$ -Band Phased-Array Antenna Transmissions

A multiple-beam optical beamformer based on highly dispersive photonic crystal fibers (PCFs) is presented. Each radio-frequency (RF) beam can be independently controlled to steer continuously. The dispersion of the fabricated PCFs is as high as -600 ps/nmldrkm at 1550 nm. Simultaneous two-beam transmission is demonstrated using two lasers with different optical wavelengths. The two wavelengths generate two independent sets of time delays, which correspond to two independent RF beams.