Joo Jongyoon, Cho Seungwan, Vakoc Benjamin J, Oh Wang-Yuhl
Department of Mechanical Engineering and the KI for Health Science and Technology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02140 USA.
IEEE Photonics Technol Lett. 2025 Jan;37(1):49-52. doi: 10.1109/lpt.2024.3508541. Epub 2024 Nov 27.
We demonstrate a chirped fiber Bragg grating (CFBG) based stretched-pulse mode-locked (SPML) wavelength-swept laser that uses both intra-cavity and post-cavity stretching. The SPML laser with complementary post-cavity stretching offers versatility in OCT imaging speed and eliminates the need for optical buffering. Using an SPML laser with a 5-m intra-cavity CFBG and a 5-m post-cavity CFBG, providing a wavelength sweep rate of 1075 nm/s, we achieved OCT imaging with a sensitivity of 97.4 dB and a single-sided 6-dB coherence length of 5.6 mm. This demonstrated more than two-fold increase in coherence length with a slight sensitivity drop of 0.6 dB compared to an SPML laser with the same wavelength sweep rate using intra-cavity stretching only. The CFBG-SPML laser with post-cavity stretching offers a compelling option for OCT systems, particularly when long imaging range is required.
我们展示了一种基于啁啾光纤布拉格光栅（CFBG）的拉伸脉冲锁模（SPML）扫频激光器，该激光器同时采用了腔内和腔外拉伸技术。具有互补腔外拉伸的SPML激光器在光学相干断层扫描（OCT）成像速度方面具有通用性，并且无需光学缓冲。使用具有5米腔内CFBG和5米腔外CFBG的SPML激光器，其波长扫描速率为1075纳米/秒，我们实现了灵敏度为97.4分贝、单边6分贝相干长度为5.6毫米的OCT成像。与仅使用腔内拉伸且具有相同波长扫描速率的SPML激光器相比，这表明相干长度增加了两倍多，灵敏度略有下降0.6分贝。具有腔外拉伸的CFBG-SPML激光器为OCT系统提供了一个极具吸引力的选择，特别是在需要长成像范围的情况下。
