Adaptive On-Line Frequency Stabilization System for Laser Diodes Based on Genetic Algorithm

Shintaro HISATAKE  Naoto HAMAGUCHI  Takahiro KAWAMOTO  Wakao SASAKI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.10   pp.2097-2102
Publication Date: 2003/10/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Lasers, Quantum Electronics
Keyword: 
frequency stabilization,  laser diode,  negative electrical feedback,  genetic algorithm,  

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Summary: 
We propose a frequency stabilization system for laser diodes (LDs), in which the electrical feedback loop response can be determined using an on-line genetic algorithm (GA) so as to attain lower LD frequency noise power within the specific Fourier frequency range of interest. At the initial stage of the stabilization, the feedback loop response has been controlled through GA, manipulating the proportional gain, integration time, and derivative time of conventional analog PID controller. Individuals having 12-bit chromosomes encoded by combinations of PID parameters have converged evolutionarily toward an optimal solution providing a suitable feedback loop response. A fitness function has been calculated for each individual in real time based on the power spectral density (PSD) of the frequency noise. The performance of this system has been tested by stabilizing a 50 mW visible LD. Long-term (τ > 0.01 s) frequency stability and its repeatability have been improved.