The FVP155LP from Thorlabs Inc. is a Polarization-Maintaining (PM) Fiber Phase Shifter that operates at a wavelength of 1440 nm - 1625 nm. It has a phase shift of 55&pi (at 150 V) and capacitance of 48 nF. This low-loss piezo-based phase shifter has a half-wave voltage of 2.73 V and resonant frequency above 20 kHz. It has an insertion loss of less than 0.05 dB and a polarization extinction ratio greater than 18 dB. This optical phase shifter supports PM1550-XP fibers and is compatible with FC/APC connectors. 

The FVP155LP requires an AC supply voltage of up to 150 V and is available in a module that measures 85.1 mm x 66.5 mm x 34.3 mm (housing) & 85.1 mm x 89.4 mm x 34.3 mm (housing with connectors). It is ideal for optical phase shifter is ideal for fiber optic communication, interferometric sensors, Q-switching & mode-locking, testing & measurement, quantum optics, and quantum communication applications.