Observation of an all-fiber Fano resonance comb

Area of Science:

• Photonics and Optical Engineering
• Fiber Optics
• Interferometry

Background:

• Fano resonances are crucial for optical devices due to their sharp spectral features.
• All-fiber systems offer advantages in terms of robustness and low loss compared to bulk optics.
• Mach-Zehnder interferometers (MZIs) are versatile platforms for manipulating light.

Purpose of the Study:

• To demonstrate a tunable all-fiber Fano resonance comb.
• To integrate a tilted fiber Bragg grating (TFBG) with an all-fiber Mach-Zehnder interferometer (MZI).
• To explore the tunability of spectral line shapes and parameters.

Main Methods:

• Incorporation of a 10° tilted fiber Bragg grating (TFBG) into an all-fiber Mach-Zehnder interferometer (MZI).
• Coupling of the discrete state from the TFBG with the continuum state of the MZI.
• Characterization of the generated Fano resonance comb over an 80 nm spectral range.

Main Results:

• Generation of a tunable all-fiber Fano resonance comb.
• Achieved continuous transitions between asymmetric Fano, electromagnetically induced transparency (EIT), and electromagnetically induced absorption (EIA) line shapes.
• Observed periodic variations in spectral parameters like the Fano parameter (q), slope rate, and extinction ratio.

Conclusions:

• The proposed all-fiber TFBG-MZI system provides a robust, low-loss, and scalable method for generating multi-Fano resonances.
• The tunable nature of the system makes it suitable for high-sensitivity sensing and optical switching applications.
• This work advances the development of integrated fiber-optic devices for advanced optical signal processing.