Heterodyne mixing of two far-infrared quantum cascade lasers by use of a point-contact Schottky diode
- 15 July 2004
- journal article
- Published by Optica Publishing Group in Optics Letters
- Vol. 29 (14) , 1632-1634
- https://doi.org/10.1364/ol.29.001632
Abstract
We demonstrate heterodyne mixing of two free-running, multimode, 3.3-THz quantum cascade lasers by use of a point-contact Schottky diode. By temperature tuning the emission wavelength of one laser, a difference frequency signal spanning the 2–4-GHz range is obtained, with a signal-to-noise ratio of 30 dB. The frequency of the heterodyne signal is subject to random fluctuations of a few megahertz, principally from instabilities in the temperatures of the devices. From single-shot measurements we derive an instantaneous linewidth for a single Fabry–Perot mode of 20 kHz, corresponding to an integration time of 3.6 ms.Keywords
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