Optical ranging and localization at beyond the coherence length of lasers

M. Mert Bayer; Berken Utku Demirel; Ataberk Atalar; Xun Li; Haoyu Xie; Ozdal Boyraz

doi:10.1117/12.2647159

15 March 2023 Optical ranging and localization at beyond the coherence length of lasers

M. Mert Bayer, Berken Utku Demirel, Ataberk Atalar, Xun Li, Haoyu Xie, Ozdal Boyraz

Proceedings Volume 12438, AI and Optical Data Sciences IV; 124380H (2023) https://doi.org/10.1117/12.2647159
Event: SPIE OPTO, 2023, San Francisco, California, United States

Abstract

Long-distance ranging in existing coherent lidar techniques suffer from the coherence length of lasers. Here we present a coherent multi-tone continuous-wave (MTCW) lidar technique that performs single-shot simultaneous ranging and velocimetry with a high resolution at distances far beyond the coherence length of a CW laser, without frequency/phase sweeping. The proposed technique utilizes relative phase accumulations at phase-locked RF sidebands and Doppler shifts to identify the range and velocity of the target after a heterodyne detection of the beating of the echo signal with an unmodulated CW optical local oscillator (LO). The predefined RF sidebands enable ultra-narrow-bandwidth RF filters in the analog or digital domain to suppress noise and achieve high SNR ranging and velocimetry. Up-to-date, we demonstrated that the MTCW-lidar could perform ranging ×500 beyond the coherence length of the laser with <1cm precision. In a quasi-CW configuration, >1km ranging is realized with <3cm precision. Moreover, we incorporate machine-learning algorithms into MTCW-lidar to identify the reflections from multiple targets and improve the range resolution. Since relative phases of RF-sidebands are utilized for ranging, and common phase noises can be suppressed in signal processing, we show that the LO in heterodyne detection does not have to be the same laser source. Hence a separate free-running laser can be used. This approach paves the way for novel optical localization. To prove the concept, we present that a receiver with a free-running CW LO can determine its relative distance to a remote transmitter at 1.5km away with a <5cm accuracy.

Conference Presentation

Citation Download Citation

M. Mert Bayer, Berken Utku Demirel, Ataberk Atalar, Xun Li, Haoyu Xie, and Ozdal Boyraz "Optical ranging and localization at beyond the coherence length of lasers", Proc. SPIE 12438, AI and Optical Data Sciences IV, 124380H (15 March 2023); https://doi.org/10.1117/12.2647159

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available