[11p-C212-1~7] 3.7 Optical measurement, instrumentation, and sensor

2:45 PM - 3:00 PM JST(5:45 AM - 6:00 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[11p-C212-5] Linewidth Narrowing of a 466 nm DFB Laser for Underwater FMCW LiDAR

〇(M1)Tomoya Ikawa¹, Wataru Kokuyama², Yoshiaki Nakajima¹ (1.Toho Univ., 2.AIST)

Keywords:

DFB laser,FMCW LiDAR,delayed self-heterodyne technique

A 466-nm distributed-feedback (DFB) laser is a promising light source for underwater FMCW LiDAR; however, linewidth broadening caused by frequency noise remains a challenge. In this study, a low-pass filter with a cutoff frequency of 8.7 Hz was inserted into the laser drive-current path, and the laser linewidth was evaluated using a delayed self-heterodyne technique combined with the β-separation-line method. As a result, the linewidth obtained with a conventional laser diode driver was reduced from 25 MHz to 1.6 MHz, achieving performance comparable to that obtained with a low-noise laser diode driver.