Light-induced switching of a chalcogenide-coated side-polished fiber device

In this report, we describe light-induced switching of the state of polarization of a side-polished fiber (SPF) coated with a chalcogenide (ChG) film, amorphous As2Se3 (a-As2Se3). The transient photodarkening effect produced by a-As2Se3 under 532-nm laser illumination modulated the refractive index of the coated ChG, changed the refractive index of the a-As2Se3-coated SPF device, and controlled and switched the phase retardation. When this design was used, a 70° phase change coupled with an optical loss of <0.2 dB was achieved at a probe-beam wavelength of 1550 nm; moreover, the extinction ratio achieved using an inline fiber polarizer was 22.8 dB.