Theoretical and Experimental Study to The Effect of Etching on Polarization Maintaining Fiber of Mach-Zehnder interferometer

Abstract

Recently tapering and etching of optical fibers gained wide attention among optical fiber researches. Therefore, this work studied theoretically and practically the effect of etching on polarization maintaining Fiber PMF that is used between two single mode fibers SMF to perform inline fiber Mach-Zehnder interferometer PM-MZI. The beat length of PMF was key parameter to design the required interference length along the final SMF after MZI arms along PMF. Three different PMF fiber lengths were studies (8,16,24cm) along with different five etching time durations with the Hydrofluoric acid HF of 40 % concentration. These durations were ranged from 5 to 30 min with 5 min apart between each separated measurement. In conclusion the PM-MZI of 16 cm length acts as good pulse compressor with pulse compression factor of 1.5 which is better than the previously gained one which was 1.105 that was gained from the same interferometer but under tunable stressing force. While 24cm PM-MZI showed red-shift toward the longer wavelengths which make it applicable for detection purposes with sensitivity of 10pm. The 8cm PMF revealed increasing in output power under the effect of etching.