Ultrahigh Extinction Ratio Leaky-Guided Hollow Core Fiber Mach-Zehnder Interferometer Assisted by a Large Core Hollow...

Area of Science:

• Optical Engineering
• Fiber Optics
• Interferometry

Background:

• Fiber optic interferometers are crucial for sensing and optical signal processing.
• Achieving high extinction ratios (ER) and broadband operation simultaneously remains a challenge.

Purpose of the Study:

• To propose and demonstrate a novel fiber Mach-Zehnder interferometer (FMZI) with ultrahigh ER, ultracompact size, and ultra-broadband characteristics.
• To investigate the influence of structural parameters on interference performance.

Main Methods:

• Fabrication of an FMZI using a short section of 10 μm hollow core fiber (HCF10) and a 50 μm HCF beam splitter (HCF50).
• Utilizing leaky-guided fiber waveguide (LGFW) principles within the HCF10 to support core and cladding modes.
• Experimental and simulation analysis of optical characteristics, including extinction ratio (ER) and free spectral range (FSR).

Main Results:

• The proposed LGFW-FMZI demonstrated similar optical characteristics in both experimental and simulation results.
• The length of HCF10 primarily controlled the free spectral range (FSR).
• The HCF50 beam splitter significantly influenced the optimal extinction ratio (ER).

Conclusions:

• The developed fiber interferometer achieves an ultrahigh ER exceeding 50 dB.
• The device offers arbitrary FSR control over an ultra-broad wavelength range (1250 nm to 1650 nm).
• The design presents a promising solution for advanced optical sensing and signal processing applications.