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Updated: Jul 17, 2026
Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
Published on: December 18, 2015
Experimental investigation of high-frequency noise and optical feedback effects using a 9.7 microm continuous-wave
Damien Weidmann1, Kevin Smith, Brian Ellison
1CCLRC Rutherford Appleton Laboratory, Space Science and Technology Department, Chilton, Didcot, Oxfordshire, OX11 0QX, UK. d.weidmann@rl.ac.uk
Abstract:
An experimental investigation of high-frequency noise, i.e., up to 3 GHz, exhibited by a 9.7 microm quantum cascade laser, is described. Noise characteristics and measurements of a liquid-nitrogen-cooled continuous-wave distributed-feedback laser are presented. Well defined sets of narrow and intense resonance peaks have been observed in the 10-300 MHz range. Measurements of relative intensity noise have been performed. It is also shown that quantum-cascade lasers are sensitive to optical feedback. The excess noise generated by the feedback has been investigated under well defined conditions. A description of the experimental phenomenon is presented along with methods of minimizing optical feedback.
