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

We propose and investigate an all-fiber thermo-optic modulator based on a side-polished twin-core fiber (TCF) Michelson interferometer (MI) coated with NaNdF(4 )nanoparticles. The MI was fabricated by tapering the splicing point between the TCF and a single mode fiber (SMF). A short suspended core fiber (SCF) is spliced to one core of the TCF to introduce a fixed optical phase difference (OPD). The side-polished core is coated with photo-thermal material NaNdF4. Owing to the ohmic heating of NaNdF4 nanoparticles under 808 nm pump laser, the effective refractive index of the polished core is changed, resulting in a phase shift of the MI. The MI has a significant modulation phase shift with 2.9 pi near the wavelength of 1260 nm and can obtain an optical switching with a rise (fall) time of 152 (50) ms. The proposed device will have a great application potential in optical modulators due to compact structure and strong robustness. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

The study presents an all-fiber thermo-optic modulator based on a side-polished twin-core fiber Michelson interferometer coated with NaNdF4 nanoparticles for optical switching. The device shows a significant modulation phase shift near the wavelength of 1260 nm and fast rise (fall) times of 152 (50) ms. With its compact structure and strong robustness, the proposed device has great potential for applications in optical modulators.