Compact all-fiber thermo-optic modulator based on a Michelson interferometer coated with NaNdF₄ nanoparticles

Area of Science:

• Photonics and Optical Engineering
• Materials Science for Optoelectronics
• Fiber Optic Sensing and Modulation

Background:

• Michelson interferometers (MI) are crucial for optical sensing and modulation.
• Developing robust and compact fiber-optic modulators is essential for advanced optical systems.
• Thermo-optic effects offer a viable mechanism for modulating light signals in fiber.

Purpose of the Study:

• To propose and investigate an all-fiber thermo-optic modulator.
• To utilize a side-polished twin-core fiber (TCF) Michelson interferometer (MI) coated with NaNdF4 nanoparticles.
• To demonstrate optical modulation through photo-thermal heating of nanoparticles.

Main Methods:

• Fabrication of an MI using tapered splicing between TCF and single-mode fiber (SMF).
• Incorporation of a short suspended core fiber (SCF) for a fixed optical phase difference (OPD).
• Coating the side-polished core with sodium neodymium fluoride (NaNdF4) nanoparticles for photo-thermal conversion.

Main Results:

• Achieved a significant modulation phase shift of 2.9π near 1260 nm wavelength.
• Demonstrated optical switching with rapid rise (152 ms) and fall (50 ms) times.
• Confirmed thermo-optic modulation via ohmic heating of NaNdF4 nanoparticles under an 808 nm pump laser.

Conclusions:

• The proposed all-fiber thermo-optic modulator exhibits excellent performance characteristics.
• The device's compact structure and robustness make it highly suitable for practical applications.
• This technology holds significant potential for future development in optical modulators.