Frequency comb swept laser with a high-Q microring filter

Dongmei Huang, Feng Li*, Chao Shang, Zihao Cheng, S. T. Chu, Alex Wai

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

11 Citations (Scopus)


Frequency comb swept lasers are the enabling technology of circular interferometric imaging, which was proposed to break the bottleneck of data acquisition and processing in optical coherence tomography (OCT) at video rate. In this paper, we propose and demonstrate a highly coherent frequency comb swept laser by using a high-quality (high-Q) microring comb filter to discretize a Fourier-domain mode-locked (FDML) laser. The microring filter has a Q factor of ∼2 × 106 and a linewidth of ∼90 MHz. To demonstrate the improvement in performance, a Fabry-Pérot comb filter with a Q factor of 6.2 × 104 and a linewidth of 3.1 GHz is also used in the experiment for comparison. Both comb filters have free spectral ranges (FSRs) of ∼50 GHz for consistence. Stable and clearly discretized temporal waveforms and frequency comb spectra with 50 GHz FSR are observed. Adoption of the high-Q microring filter narrows the instantaneous linewidth of theFDMLlaser down to 1.5 GHz. TheOCTsystem with the frequency comb swept laser source with a microring filter demonstrates an ultralong imaging range, which has a 6, 10, and 15 dB sensitivity roll-off length of ∼53, ∼73, and over 100 mm, respectively.

Original languageEnglish
Pages (from-to)904-911
Number of pages8
JournalPhotonics Research
Issue number6
Early online date26 May 2020
Publication statusPublished - Jun 2020

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics


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