All-optical rewritable birefringence on azopolymer-coated optical fiber tips

In this work, we present a novel method to induce and tune birefringence on an optical fiber tip by using a deposited layer of the azopolymer PAZO. The birefringence was written and erased with a pump laser at 532 nm, and read with a probe laser at 1550 nm. Maximum effective birefringence values of 0.060 ± 0.003 were achieved with the pump laser turned on, stabilizing at 0.058 ± 0.003 with the pump laser turned off. Phase differences in the order of a quarter-wave plate were also attained with Δ ϕ = 0.5770 π ± 0.0004 π , for the highest thickness sample. The proposed device is simple to fabricate, has good reproducibility between measurements, and shows promising potential for applications requiring polarization control in optical fibers.