Photothermal effects in passive fiber Bragg grating resonators

Area of Science:

• Optics and Photonics
• Materials Science
• Thermal Physics

Background:

• Passive resonators, such as Fabry-Perot cavities, are susceptible to photothermal effects.
• Absorption of circulating optical energy within resonators leads to undesirable heat generation.
• This heat induces thermal expansion and refractive index changes, altering the resonator's optical path length.

Purpose of the Study:

• To develop a simplified dynamic numerical model for photothermal effects in passive fiber Bragg grating resonators.
• To experimentally validate the predictions of the numerical model.
• To understand the influence of photothermal effects on the resonance condition of fiber Bragg grating resonators.

Main Methods:

• Development of a simplified dynamic numerical model simulating photothermal effects.
• Utilizing fiber Bragg gratings as passive resonators.
• Experimental observation and measurement of photothermal-induced changes in resonator properties.

Main Results:

• The numerical model successfully predicts the dynamic behavior of photothermal effects.
• Experimental results confirm the significant impact of photothermal effects on the resonance condition.
• Observed changes in optical path length and round-trip phase due to heat accumulation.

Conclusions:

• Photothermal effects are a critical factor influencing the performance of passive fiber Bragg grating resonators.
• The developed numerical model provides a valuable tool for analyzing and mitigating these effects.
• Understanding photothermal dynamics is essential for designing stable and high-performance optical resonators.