All-fiber Mach-Zehnder curvature sensor based on multimode interference combined with a long-period grating

Area of Science:

• Optics and Photonics
• Fiber Optic Sensors
• Interferometry

Background:

• Mach-Zehnder interferometers are widely used for sensing applications.
• Integrating multimode interference (MMI) with fiber gratings offers unique light manipulation capabilities.
• Developing novel fiber optic configurations for enhanced sensitivity is crucial.

Purpose of the Study:

• To propose and demonstrate a novel Mach-Zehnder interferometer (MZI) configuration.
• To utilize a combination of multimode interference (MMI) and long-period fiber grating (LPG) for sensing.
• To evaluate the sensor's performance for bending detection.

Main Methods:

• Fabrication of an MZI structure by splicing a multimode fiber (MMF) section between two single-mode fibers (SMFs).
• Incorporation of a long-period fiber grating (LPG) after the MMF section to couple light back into the core.
• Characterization of the device's response to external bending stimuli.

Main Results:

• Successfully demonstrated a novel fiber optic Mach-Zehnder interferometer.
• The proposed MMI-LPG configuration effectively guided light through core and cladding modes.
• The sensor exhibited a measurable response to applied bending, confirming its functionality.

Conclusions:

• A novel fiber optic Mach-Zehnder interferometer based on MMI and LPG has been successfully designed and demonstrated.
• This configuration provides a new platform for developing sensitive fiber optic sensors.
• The device shows promise as an effective bending sensor.