Improvement of dynamic range and repeatability in a refractive-index-sensing optical comb by combining saturable-absorber-mirror mode-locking with an intracavity multimode interference fiber sensor

Mode-locked fiber comb equipped with multi-mode-interference fiber sensor functions as high-precision refractive-index (RI) sensor benefitting from precise radio-frequency measurement. However, its dynamic range and repeatability are hampered by inherent characteristics in nonlinear-polarization-rotation mode-locking oscillation. In this article, we introduce saturable-absorber-mirror mode-locking for RI sensing with wide dynamic range and high repeatability. While the RI dynamic range was expanded to 41.4 dB due to high robustness to cavity disturbance, self-starting capability without the need for polarization control improves the RI sensing repeatability to 1.10×10-8 every mode-locking activation. Improved dynamic range and repeatability will be useful for enhanced performance of RI sensing.

This is a peer-reviewed, un-copyedited version of an article accepted for publication/published in Japanese Journal of Applied Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.7567/1347-4065/ab219a.