Advances in Optical Phased Array Technology
Published in SPIE Proceedings Volume 6304, Free-Space Laser Communications VI; 63040T (2006) https://doi.org/10.1117/12.679551
Commercially available Liquid Crystal on Silicon (LCoS) Optical Phase Arrays (OPA) are capable of non-mechanically beamsteering up to ±3 degrees at 1550 nm. While the existing technology is useful for many applications such as laser communications and pulse-shaping, it is desirable to increase the steer angle and decrease the response time of the OPA. This was accomplished through a research effort funded by Langley Research Center at NASA. Under this research effort Boulder Nonlinear Systems (BNS) designed a new 1x12288 pixel OPA. In the new backplane design the pixel pitch was decreased from 1.8 um to 1.6 um, the backplane voltage was increased from 5 volts to 13 volts, and the aperture was increased from 7.4 x 6.0 mm to 19.66 x 19.66 mm. The OPA, when built with new liquid crystals and calibrated with new automated calibration procedures demonstrated a greater than 2x improvement in steer angle. The OPA that was tested, which was built for operation at 1550 nm, demonstrated the ability to steer to ±6.95 degrees. Additionally the relaxation time of the OPA was improved to 24.8 ms. This paper discusses the benefits of the new backplane design, the liquid crystal (LC) properties that are most desirable for beamsteering, the implementation of the automated calibration procedures, and the results.