Highly Modulated In-Fiber Mach-Zehnder Interferometer Based on an Ultracompact Leaky-Guided Liquid Core

Area of Science:

• Optical Engineering
• Fiber Optics
• Sensor Technology

Background:

• Interference-based fiber optic sensors are crucial for precise measurements.
• Developing compact sensors with high sensitivity remains a key challenge.
• Liquid core waveguides offer unique optical properties for sensing applications.

Purpose of the Study:

• To propose and demonstrate a novel ultracompact leaky-guided liquid core fiber Mach-Zehnder interferometer (LLCFMZI) sensor.
• To investigate the sensor's performance in modulating interference spectra for temperature sensing.
• To evaluate the temperature sensitivity and thermal optics coefficient (TOC) for different liquids.

Main Methods:

• Fabrication of an LLCFMZI using a micro-sized hollow-core fiber (HCF) spliced to a single-mode fiber (SMF) with a tilted end face.
• Utilizing a leaky-mode optical waveguide (LMOW) mechanism within the liquid core.
• Experimental measurement of interference spectra modulation and temperature sensitivity for various liquids.

Main Results:

• The LLCFMZI demonstrated high modulation of interference spectra within the 1250-1650 nm range.
• High temperature sensitivities were achieved, with values up to +13.87 nm/°C for Cargille-liquid (nD = 1.40).
• Experimental results showed good agreement between measured and theoretical values, validating the sensor's effectiveness.

Conclusions:

• The proposed LLCFMZI is an effective ultracompact sensor for high-sensitivity temperature measurements.
• The sensor's performance is influenced by the liquid core's thermal optics coefficient (TOC).
• This technology holds potential for advanced optical sensing applications requiring high modulation and sensitivity.