In-line Fiber Mach-Zehnder Interferometer with Enhanced Strain Sensitivity Using Off-Axis Coating

This paper demonstrates a Mach-Zehnder interferometer (MZI) with enhanced strain sensitivity. Strain sensitivity enhancement is achieved by encapsulating the MZI with off-axis coating. Experiments comparing the off-axis with on-axis encapsulation reveals that the enhancement achieved is at least tenfold. Effect of various types of elastic coating is also investigated. The results show that softer coating with give a higher strain sensitivity. This technique offers a simple packaging to enhance any discrete fiber optic sensor.