Experimental verification of coherent tracking system based on fiber nutation

Area of Science:

• Optics and Photonics
• Aerospace Engineering
• Telecommunications

Background:

• Inter-satellite laser communication requires precise pointing accuracy.
• Beaconless communication systems eliminate the need for separate tracking beams, simplifying design.
• Existing tracking systems face challenges in accuracy and sensitivity.

Purpose of the Study:

• To develop and validate a coherent tracking system for beaconless inter-satellite laser communication.
• To utilize fiber nutation and coherent demodulation for accurate boresight error calculation.
• To assess the system's performance under varying signal power conditions.

Main Methods:

• A piezo-electric ceramic tube (PCT) drives a single-mode fiber (SMF) for nutation.
• Coherent demodulation calculates boresight error from signal light intensity fluctuations.
• Theoretical analysis and experimental verification were performed.

Main Results:

• The system achieved a receiving field of view (FOV) greater than 300 microradians.
• A closed-loop tracking bandwidth of approximately 115 Hz was demonstrated.
• A boresight error of 80 microradians was calculated with less than 10% error.
• Performance remained stable across a signal power range of 1 nW to 10 nW.

Conclusions:

• The developed coherent tracking system effectively addresses the needs of beaconless inter-satellite laser communication.
• The system demonstrates high accuracy, a wide FOV, and robust performance.
• This technology is significant for advancing satellite communication capabilities.