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Updated: Jun 20, 2026
08:48
Low-cost Custom Fabrication and Mode-locked Operation of an All-normal-dispersion Femtosecond Fiber Laser for Multiphoton Microscopy
Published on: November 22, 2019
Summary
Researchers developed a novel fiber optic modal coupler that precisely controls light modes. This device enables efficient mode coupling and functions as an in-line polarizer, significantly improving optical device performance.
Area of Science:
- Optics and Photonics
- Fiber Optics Engineering
Background:
- Single-mode fibers below cutoff wavelength guide multiple modes with different phase velocities.
- Coherent coupling between these modes can be induced by periodic stress.
Purpose of the Study:
- To develop and characterize a novel fiber optic modal coupler.
- To demonstrate its application in a Mach-Zehnder interferometer and as a polarizer.
Main Methods:
- Utilizing periodic stress on a two-mode fiber to induce modal coupling.
- Fabricating and integrating two couplers into a fiber Mach-Zehnder interferometer.
- Characterizing polarization sensitivity and extinction ratios.
Main Results:
- Achieved efficient coupling to a second-order mode with < -40 dB residual fundamental mode power.
- Constructed a Mach-Zehnder interferometer with > 30 dB on/off ratio.
- Demonstrated polarization sensitivity with a 36 dB extinction ratio, enabling in-line polarization functionality.
Conclusions:
- The developed modal coupler effectively controls light propagation in optical fibers.
- This technology offers significant improvements for interferometric and polarization-based fiber optic devices.
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