Bandwidth efficient coherent lidar based on phase-diversity detection

Abstract

Bandwidth efficient coherent lidar based on phase-diversity detection is reported for the first time, to the best of our knowledge, which allows the doubling of bandwidth efficiency through the simultaneous utilization of the in-phase (I) and quadrature (Q) components. By maintaining RF phase continuity between linearly frequency-chirped I and Q components through digital signal processing, the range resolution of the lidar system can be improved.

Research on wavelength hopping low probability of intercept coherent LiDAR technology

“…The use of coherent detection can improve the detection sensitivity and is insensitive to background light [9]. A broadband 90° optical hybrid is used to mix the received signal beams with phase encoding and the local oscillator beams and generate four mixed signals with a relative phase difference of 90° [10]. Distance estimation is conducted by a matched filter [11,12].…”

Impact of Laser Phase Noise on Ranging Precision Within and Beyond Laser Coherence Length in FMCW LiDAR

“…The booming of the autonomous vehicles market and other sensing applications in recent years have stimulated the development of light detection and ranging (LiDAR) techniques. In particular, frequency-modulated continuouswave (FMCW) LiDAR has attracted a lot of interest, as it offers a higher receiver sensitivity, ranging resolution and precision over a longer distance compared to time-of-flight (TOF) LiDAR [1][2][3].…”

Frequency-Modulated Chirp Signals for Single-Photodiode Based Coherent LiDAR System

“…Alternatively, a balanced phase-diversity coherent receiver based on an optical 90 • hybrid can be employed [24]. The combination of an IQM and a balanced phase-diversity coherent receiver offers good performance, as advanced complex signal waveforms can be designed for improving the distance and velocity estimation accuracy [25], [28]; however, the high cost and complexity of this receiver architecture remain the main concern for practical implementation. With 3-dB coupler-based balanced detection, a precise 50/50 split of the coupler and two balanced photodiodes are required in order maximise the common mode rejection ratio and to completely eliminate the DD beating interference (BI).…”