Temperature insensitive single-mode-multimode-single-mode fiber optic structures with two multimode fibers in series.

Area of Science:

• Optoelectronics
• Fiber Optics
• Materials Science

Background:

• Fiber optic devices are susceptible to temperature variations, affecting their performance.
• Multimode interference (MMI) is a key phenomenon in various photonic devices.
• Existing MMI-based devices often suffer from temperature cross-sensitivity.

Purpose of the Study:

• To propose and demonstrate a novel fiber optic structure for temperature-insensitive operation.
• To enable the development of robust fiber optic devices unaffected by environmental temperature fluctuations.
• To achieve zero temperature cross-sensitivity in multimode interference-based devices.

Main Methods:

• Fabrication of a single-mode-multimode-single-mode (SMS) fiber structure.
• Utilizing two in-series multimode fibers with carefully selected lengths and opposite temperature sensitivities.
• Derivation of an approximate expression to estimate the required length ratio of the multimode fiber sections.

Main Results:

• Successful demonstration of a temperature-insensitive SMS fiber optic structure.
• Experimental validation of the derived approximate expression for multimode fiber length ratio.
• Achieved good agreement between theoretical predictions and experimental outcomes.

Conclusions:

• The proposed SMS fiber structure effectively mitigates temperature-induced cross-sensitivity.
• The derived expression provides a practical tool for designing such temperature-insensitive devices.
• This research facilitates the realization of reliable fiber optic devices for diverse applications.