US 12,449,536 B1
Ultraprecision frequency-domain light detection and ranging (LiDAR) system for remote micro-movement sensing
Mohamed Yehia Mohamed Shalaby, Riyadh (SA)
Assigned to IMAM MOHAMMAD IBN SAUD ISLAMIC UNIVERSITY, Riyadh (SA)
Filed by IMAM MOHAMMAD IBN SAUD ISLAMIC UNIVERSITY, Riyadh (SA)
Filed on Feb. 18, 2025, as Appl. No. 19/056,225.
Int. Cl. G01S 17/26 (2020.01); G01S 7/481 (2006.01); G01S 7/484 (2006.01); G01S 7/4865 (2020.01); G01S 17/88 (2006.01)
CPC G01S 17/26 (2020.01) [G01S 7/4818 (2013.01); G01S 7/484 (2013.01); G01S 7/4865 (2013.01); G01S 17/88 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An ultraprecision frequency-domain light detection and ranging (LiDAR) system for remote micro-movement sensing, comprising:
a laser diode connected to a power source;
a bandpass filter connected to the laser diode, wherein the bandpass filter is configured to modulate a power provided by the power source by a radio frequency (RF) signal, wherein the modulated power causes the laser diode to generate intensity modulated optical signals;
a Michelson interferometer including:
a 50/50 directional coupler connected to the laser diode, wherein the 50/50 directional coupler is configured to split the intensity modulated optical signals into a first optical path and a second optical path, wherein:
the first optical path comprises a fiber-optic delay line configured to generate phase shifted intensity modulated optical signals and a silver coated end connected to the fiber-optic delay line at a distance l1 from the laser diode, wherein the silver coated end is configured to reflect the phase shifted intensity modulated optical signals back towards the 50/50 directional coupler,
the second optical path comprises a semiconductor optical amplifier (SOA) configured to amplify the intensity modulated optical signals on the second optical path to compensate for signal losses, an optical collimator connected between the SOA and a free-space propagation region and a target located beyond the free-space propagation region at a distance l2 from the laser diode, wherein the target is configured to reflect the amplified intensity modulated optical signals back towards the 50/50 directional coupler along the second optical path;
a photodetector connected to the 50/50 directional coupler, wherein the photodetector is configured to receive the phase shifted intensity modulated optical signals and the amplified intensity modulated optical signals and convert the phase-shifted intensity modulated optical signals and the amplified intensity modulated optical signals into electrical signals; and
a feedback loop comprising the bandpass filter and a frequency-domain analyzer comprising one of a spectrum analyzer, a phase detector and a phase-locked loop, wherein the frequency-domain analyzer is configured to identify frequency shifts in the electrical signals induced by micro-movements of the target.