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Updated: May 14, 2026
12:18
Microwave Photonics Systems Based on Whispering-gallery-mode Resonators
Published on: August 5, 2013
Characterization of optical resonators with an incoherent light
1Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568, Japan. h-tsuchida@aist.go.jp
Optics Express
|February 8, 2013
Summary
A new method measures optical resonator properties using broadband light. This technique simplifies determining free spectral range (FSR) and bandwidth, overcoming limitations of previous laser-based approaches.
Area of Science:
- Photonics and Optical Engineering
- Spectroscopy
- Resonator Characterization
Background:
- Accurate measurement of optical resonator parameters like free spectral range (FSR) and bandwidth is crucial for various photonic applications.
- Conventional methods often rely on complex and expensive frequency-swept lasers, posing practical challenges.
Purpose of the Study:
- To introduce a novel, simplified technique for measuring the FSR and bandwidth of optical resonators.
- To demonstrate the effectiveness of this new method on different types of optical resonators.
Main Methods:
- Utilizing broadband light as input to an optical resonator, generating an incoherent frequency comb.
- Employing photodetection to capture heterodyne beat signals between the comb lines.
- Analyzing the spectrum of the beat signals to extract FSR and bandwidth.
Main Results:
- The output of the resonator forms a frequency comb where spacing and linewidth directly relate to FSR and bandwidth.
- Successful characterization of fiber-optic Fabry-Perot and ring resonators was achieved.
- The technique demonstrated capability in measuring resonators with bandwidths as low as 10 kHz.
Conclusions:
- The proposed technique offers a simple and effective alternative for optical resonator characterization.
- It overcomes the limitations associated with traditional frequency-swept laser methods.
- This method provides accurate measurements for resonators with narrow bandwidths.
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