Liquid crystal-based self-aligning 2 × 2 wavelength routing module

A novel retroreflective polarization insensitive 2 × 2 fiber optic switch (FOS) using programmable quarter waveplates (QWPs) is introduced. Key features include low polarization sensitivity and a self-aligning module via a compact retroreflective structure. A proof of concept 2 × 2 FOS using ferroelectric liquid crystal (FLC)-based programmable QWPs is demonstrated, providing a response speed of 394 μs and a low 10.14-mW total electrical power consumption for the worst case. Multiwavelength switch operation in the 1550-nm wavelength region indicates an average optical loss of 6.02 dB with a ±0.18-dB loss fluctuation, and an optical coherent crosstalk of -21.6 dB with a ±0.84 dB variation over a 60-nm bandwidth. The temperature dependence of our switch is investigated over a 17°C range, indicating an average 5.80-dB optical loss with a ±0.13-dB fluctuation, and an average optical coherent crosstalk of -20.5 dB with a fluctuation of ±0.42 dB. An average polarization dependent loss of 0.4 dB is also measured. A time-multiplexed FLC device addressing technique is introduced for FOS to achieve long duration operation.