Hybrid integrated low noise linearly chirped Frequency Modulated Continuous Wave laser source based on self-injection to external cavity

TL;DR

This paper presents a low noise, wide bandwidth, linearly chirped FMCW laser source with thermal tuning, demonstrating high precision in fiber sensing and potential for FMCW LiDAR applications.

Contribution

It introduces a novel hybrid integrated laser source with self-injection external cavity and thermal tuning for wide, linear frequency modulation with low noise.

Findings

42 GHz continuous frequency tuning achieved

49.86 Hz intrinsic linewidth under static operation

3 m length difference detection at 45 km in fiber

Abstract

A low noise linearly frequency modulated continuous wave laser source with a wide frequency bandwidth is demonstrated. By two-dimensional thermal tuning, the laser source shows 42 GHz continuous frequency tuning with 49.86 Hz intrinsic linewidth under static operation. For dynamical FMCW, the laser source has 10.25 GHz frequency bandwidth at 100 Hz chirped frequency and 5.56 GHz at 1 kHz chirped frequency. With pre-distortion linearization, it can distinguish 3 m length difference at 45 km distance in the fibre length measured experiment, which demonstrate a potential for application in ultra-long fibre sensing and FMCW LiDAR.