Thermo-optic coefficient

The thermo-optic coefficient of a material is the change in refractive index with the response to temperature. This value itself also depends on the present temperature of the material and so has second-order behaviours. At low temperatures (0-400 °C), the relationship is linear but at higher ones it exhibits a second-order polynomial behaviour.[1]

Applications

The relationship can be used in temperature measurement by Fibre Bragg gratings (FBGs) where if no physical strain is applied, a Bragg's Wavelength shift of 1 pm per 0.1 °C temperature change can be measured.

This application can be used as a thermal lens-based photonic diode along with semiconductor properties with different material combinations to make a device on liquid or solid transition from aluminium-based low band gap material with act as a photonic diode with sufficient power (depending on the material choice and application) and concentration especially for higher wavelength and concentration based photonic diode. It is employed in Optical limiting , optical microscopy, optical communication optical switching, etc.[2]

References

1. Wang, Wenyuan (May 17, 2015). Measurements of thermo-optic coefficient of standard single-mode fiber under large temperature range. 2015 International Conference on Optical Instruments and Technology: Optical Sensors and Applications. doi:10.1117/12.2193091.
2. Babu, Mahalingam; Bongu, Sudhakara Reddy; Shetty, Pritam P.; Varrla, Eswaraiah; Reddy, G Ramachandra; Bingi, Jayachandra (1 December 2023). "Demonstration of spatial self phase modulation based photonic diode functionality in MoS2/h-BN medium". Materials Science in Semiconductor Processing. 168: 107831. arXiv:2309.09209. doi:10.1016/j.mssp.2023.107831. ISSN 1369-8001.