Tapered splicing points SMF-PCF-SMF structure based on mach-zehnder interferometer for enhanced refractive index sensing

Abstract EN

Photonic crystal fiber interferometers (PCFIs) are widely used for sensing applications.

This work presented solid core-PCFs based on Mach-Zehnder modal interferometer for sensing refractive index.

The general structure of sensor was applied by splicing short lengths of PCF in both sides with conventional single mode fiber (SMF-28).To apply modal interferometer theory collapsing technique based on fusion splicing used to excite higher order modes (LP01 and LP11).

A high sensitive optical spectrum analyzer (OSA) was used to monitor and record the transmitted wavelength.

This work studied a Mach-Zahnder interferometer refractive index sensor based on splicing point tapered SMF-PCF-SMF.

Relation between refractive index sensitivity and taper waist diameter were studied through simulation and experiments.

The experimental and simulation results show that sensitivity would be increased with a decrease of taper waist diameter.

The response of the PCFI is observed for a range of refractive index values from (1.33 to 1.38).

When the length of PCF was (4)cm with different taper waist diameter (125,107,90,60)μm, the maximum refractive index sensitivity of (20 pm / RIU) was achieved.

When taper waist diameter became (60)μm, the rate of increase in sensitivity was 12.4% compared with the taper waist diameter (125)μm.