Optoelectronic feedback loop for relaxation oscillation intensity noise suppression in Tm-Ho:YAG laser

Author

Svelto, C. ; Taccheo, S. ; Marano, M. ; Sorbello, G. ; Laporta, P.

Author_Institution

Dipt. di Elettronica e Inf., Politecnico di Milano, Italy

Volume

36

Issue

19

fYear

2000

fDate

9/14/2000 12:00:00 AM

Firstpage

1623

Lastpage

1624

Abstract

An optoelectronic feedback loop that can be used to effectively reduce the intensity noise of a 2.1 μm Tm-Ho:YAG laser has been designed. The feedback circuit is based on a variable-gain biquadratic bandpass filter with adjustable central frequency and quality factor, providing a high loop gain around the relaxation oscillation frequency of the laser and a closed-loop phase margin larger than 50°. The relaxation oscillation peak in the intensity noise spectrum was completely suppressed in closed-loop operation, and a noise reduction of up to 24 dB was obtained

Keywords

band-pass filters; closed loop systems; holmium; laser beams; laser feedback; laser noise; optical filters; optical pumping; oscillations; relaxation; solid lasers; thulium; 2.1 mum; Tm,Ho:YAG laser; YAG:Tm,Ho; YAl5O12:Tm,Ho; adjustable central frequency; closed-loop operation; closed-loop phase margin; feedback circuit; high loop gain; intensity noise; intensity noise spectrum; noise reduction; optoelectronic feedback loop; quality factor; relaxation oscillation frequency; relaxation oscillation intensity noise suppression; relaxation oscillation peak; variable-gain biquadratic bandpass filter;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el:20001179

Filename

871152