Dual-Frequency Doppler LiDAR Based on External Optical Feedback Effect in a Laser.

Zhuqiu Chen,Jun Tong,Qinghua Guo,Yuxi Ruan,Yanguang Yu,Jiangtao Xi,Bairun Nie

doi:10.3390/s20216303

Abstract

A novel Dual-frequency Doppler LiDAR (DFDL) is presented where the dual-frequency light source is generated by using external optical feedback (EOF) effect in a laser diode (LD). By operating a LD at period-one (P1) state and choosing suitable LD related parameters, a dual-frequency light source can be achieved. Such a dual-frequency source has advantages of the minimum part-count scheme, low cost in implementation, and ease in optical alignment. Theory and system design are presented for the proposed DFDL for velocity measurement with high measurement resolution. The proposed design has a potential contribution to the Light Detection And Ranging (LiDAR) in practical engineering applications.

Highlights

Light Detection And Ranging (LiDAR) is a method for measuring distances by illuminating the target with laser light and measuring the reflection with a sensor [1]
With the change of one or more controllable system parameters in external optical feedback (EOF) system, such as injection current J, feedback strength κ, external cavity L, the laser diode (LD) will undergo from steady state, P1 state, period-doubling state, and chaos state
There is only one optical frequency component emitted by a LD

Summary

Introduction

Light Detection And Ranging (LiDAR) is a method for measuring distances (ranging) by illuminating the target with laser light and measuring the reflection with a sensor [1]. The single frequency Doppler LiDAR systems have the ability to measure wind velocities with a deviation over ranges of up to 0.39 m/s [10], to achieve the atmospheric measurement over a 51-day continuous and unattended field deployment with a range of 7.5 km for observing the boundary layer [11], and detect air turbulence in clear air at a range of 9.3 km at cruising altitudes [12]. They are highly sensitive to external disturbances. The results show that the proposed DFDL system can reach up to 4.8 μm/s velocity measurement resolution with 31.21 GHz microwave beat frequency

Generation of Dual-Frequency Laser

Setup and Principle of DFDL System

Conclusions