Liquid crystals for lasercom a

摘要

Abstract: Nematic liquid crystals (NLCs) have electronically tunable birefringence and can be used as voltage-controlled switches for channel or redundancy beam switching in a lasercom terminal. To assess the performance of such a switch, evaluation has been made of the operating voltage, transmission efficiency, polarization crosstalk, and long-term operational reliability of an NLC device at four laser diode wavelengths. Preliminary results are encouraging. Transmission is around 95%, and polarization rotation purity is comparable to that obtained with a quartz or polymer waveplate, making this solid-state, voltage-controlled waveplate competitive with a conventional implementation that uses a mechanically inserted or rotated half-wave plate.!