Enhancement the sensitivity of humidity sensor based on an agarose infiltration reflection-type photonic crystal fiber interferometer

Abstract EN

Photonic Crystal Fiber Interferometers (PCFIs) are widely used for sensing applications.

This work presents the fabrication and study the characterization of a relative humidity sensor based on a polymer-infiltrated photonic crystal fiber that operates in a Mach- Zehnder Interferometer (MZI) reflection mode.

The fabrication of the sensor only involves splicing and cleaving Photonic Crystal Fiber (PCF) with Single Mode Fiber (SMF).

A stub of (LMA-10) PCF spliced to SMF (Corning-28).

In the splice regions.

The PCFI sensor operation based on the adsorption and desorption of water vapour at the silica-air interface within the PCF.

The sensor shows a high sensitivity to RH variations from (27% RH - 95% RH), with a change in its reflected power and the position of the interference peaks is found to be shifted that the interference pattern with a 100 nm span can be observed with high humidity sensitivity of (8.49 pm / %RH) is achieved with compact (4mm) PCF length .

The sensor has the advantages for suitable for monitoring humidity in microenvironments.

The repeatability, long-term stability, measurement accuracy.

Wide humidity range.

The response time of the sensor is found to be 1.4 sec for a change in RH of 50 %RH.

The fast response time suggests that the sensor can potentially be used as a human breath rate monitor in a clinical situation.