Enhancement of coherent laser radar performance by predetection amplification

Area of Science:

• Optics and Photonics
• Laser Technology
• Radar Systems

Background:

• Coherent laser radar systems require high signal gain and low noise.
• Predetection amplification is crucial for enhancing sensitivity in laser radar.

Purpose of the Study:

• To investigate a long-path carbon dioxide laser amplifier as a predetection amplifier for coherent laser radar.
• To measure the signal gain and noise characteristics of the amplifier.
• To determine the signal-to-noise enhancement in a Doppler radar system.

Main Methods:

• Utilized a coaxial radio frequency discharge gain medium.
• Incorporated a Herriott cell folding system for long-path amplification.
• Measured amplifier gain, noise, and signal-to-noise ratio under various operating conditions.

Main Results:

• The carbon dioxide laser amplifier demonstrated significant signal gain.
• Measured noise characteristics were analyzed.
• A maximum signal-to-noise enhancement factor of 12.4 dB was achieved for a continuous-wave (cw) gain cell.

Conclusions:

• The investigated laser amplifier is effective for coherent laser radar applications.
• Experimental results closely matched theoretical predictions.
• The system offers substantial signal-to-noise enhancement for Doppler radar.