Polarization-dependent in-line quasi-Michelson interferometer based on PM-PCF reflection.

Area of Science:

• Optoelectronics
• Fiber Optics Sensing
• Interferometry

Background:

• Interferometric fiber optic sensors offer high sensitivity for various physical parameter measurements.
• Photonic crystal fibers (PCF) provide unique light manipulation properties for advanced sensor designs.
• Developing compact, multiparameter sensors remains a key challenge in optical sensing.

Purpose of the Study:

• To propose and experimentally demonstrate a novel in-line fiber quasi-Michelson interferometer (IFQMI) for multiparameter sensing.
• To investigate the sensor's performance for strain, torsion, and temperature measurements.
• To highlight the potential of the IFQMI for compact and versatile sensing applications.

Main Methods:

• Fabrication of the IFQMI sensing head by splicing polarization-maintaining photonic crystal fiber (PM-PCF) with single-mode fiber (SMF).
• Excitation of cladding modes in PM-PCF via core-mismatch splicing, leading to interference between orthogonal polarized modes.
• Experimental characterization of the IFQMI for strain, torsion, and temperature sensitivities.

Main Results:

• The IFQMI demonstrated strain sensitivity of -1.3 pm/με and torsion sensitivity of -19.17 pm/deg.
• A temperature sensitivity of 9.9 pm/°C was observed for a 10 cm long PM-PCF device.
• The sensor exhibited a well-defined interference pattern due to cladding-orthogonal mode interference.

Conclusions:

• The proposed IFQMI is a viable and compact sensor for simultaneous strain, torsion, and temperature measurements.
• The use of PM-PCF enables the excitation and interference of cladding modes for sensing.
• The IFQMI's compact structure makes it suitable for various multiparameter sensing applications.