Tungsten trioxide integrated all-fiber phase shifter

• Main Authors: Affendy, N.B., Abu Bakar, M.H., Zainol Abidin, N.H., Muhammad, F.D., Mustapha Kamil, Y.
• Format: Article
• Published: Elsevier BV 2023
• Online Access: http://psasir.upm.edu.my/id/eprint/108364/; https://linkinghub.elsevier.com/retrieve/pii/S0030402623002917

This work proposes an all-fiber phase shifter based on tapered optical fiber spin coated with tungsten trioxide (WO3). Different WO3 coating thickness was tested by varying the spin coating time from 30 to 150 s at constant 1000 rpm. Evanescent field induced by the non-adiabatic taper generated thermal optic effect through interaction with the WO3 layer, which changed its refractive index and produced phase shifting effect. The optimum spin coating time of 120 s yielded maximum phase shift of 2.52 π with wavelength shift coefficient of 0.0859 nm/mW as 980 nm pump power was varied up to 220 mW. Integration of phase shifter in fiber laser cavity produced wavelength tuning with shift coefficient of about 0.06 nm/mW. This work presents a feasible all-fiber phase shifter with simple fabrication and operation that suits current need in communication field.