Demonstration of high-speed wireless data transmission using passive silica optical phased array

We demonstrate high-speed data transmission with beam-steering using an as-fabricated silica optical phased array (OPA) chip. In this OPA, a constant optical path difference was built up in arrayed waveguide grating (AWG) delay lines for allocation of sequential phase delay, which enabled the beam-steering following the wavelength variation. Our designed and fabricated 1x101 silica OPA showed a beam steering of 15.4 degrees by wavelength tuning of 30.37 nm. Combining a cylindrical lens, the beam divergence angle of the OPA beam was 0.56 degrees/0.41 in the transversal/longitudinal direction. Using the fabricated silica OPA, 25 Gbps data transmission over a free-space range of 5 m distance was experimentally demonstrated employing an appropriate cylindrical lens, dense wavelength-division multiplexing (DWDM) tunable transceiver, and fiber collimator as a receiver. The experimental results showed that free-space data transmission through the silica OPA was successfully achieved with error-free performances regardless of the beam-steering angle.