Tunable integrated ring resonators by femtosecond laser micromachining

TL;DR

This paper demonstrates a femtosecond laser micromachined tunable racetrack resonator operating at telecom wavelengths, featuring high Q factor and dynamic control, suitable for various optical sensing and filtering applications.

Contribution

It introduces a novel FLM-fabricated tunable resonator with integrated thermo-optic phase shifters, enabling dynamic spectral tuning and Q factor control.

Findings

Achieved a Q factor of 8 x 10^5 at critical coupling.

Demonstrated resonance tuning via thermo-optic phase shifters.

Enabled dynamic control of the resonator's spectral properties.

Abstract

Femtosecond Laser Micromachining (FLM) is a powerful technology for the fabrication of photonic devices. In this context, the integration of resonant elements within the platform represents a key advancement, enhancing both its versatility and its compatibility with a wide range of optical and fluidic components specifically enabled by this technique. Here, we report the realization of a tunable racetrack resonator fabricated by FLM and operating at telecom wavelengths. Leveraging low-loss waveguides, we obtained a Q factor of the resonator as high as 8 x 10^5 at critical coupling. Moreover, by integrating two thermo-optic phase shifters, we achieved both resonance tuning and dynamic control of the Q factor. This capability makes the device highly versatile for applications requiring dynamic spectral control, such as tunable filters, gyroscopes, and sensors.