Random-modulated pulse lidar using a gain-switched semiconductor laser with a delayed self-homodyne interferometer

Area of Science:

• Optoelectronics
• Laser Physics
• Lidar Technology

Background:

• Traditional lidar systems face challenges with ranging ambiguity and detection interference.
• Existing methods like chaos-modulated pulses have limitations in precision and complexity.
• Gain-switched semiconductor lasers exhibit unique wavelength fluctuation characteristics.

Purpose of the Study:

• To propose and investigate a novel method for generating random-modulated pulses for lidar applications.
• To mitigate ranging ambiguity and detection interference using non-repetitive pulse generation.
• To evaluate the performance of these pulses in terms of signal-to-noise ratio (SNR) and ranging precision.

Main Methods:

• Utilized a gain-switched semiconductor laser coupled with a delayed self-homodyne interferometer (DSHI).
• Generated random and down-chirped modulated pulses by beating two laser pulses with frequency detuning.
• Investigated pulse waveforms, spectra, SNR, precision, and cross-correlation under varying DSHI delay, current, and pulsewidth.

Main Results:

• Successfully generated random-modulated pulses without complex external modulation.
• Achieved optimal ranging precision of approximately 1 mm with an SNR over 12 dB.
• Demonstrated superior ranging precision compared to chaos-modulated pulse lidar.

Conclusions:

• The proposed gain-switched homodyne scheme effectively generates high-performance random-modulated pulses for lidar.
• This method offers a simpler and more precise alternative for lidar applications.
• Successfully demonstrated 3D imaging and profiling with good precision using the developed lidar system.