Using a discrete thermal model to obtain a linear frequency ramping in a frequency-modulated continuous-wave system
2005 (English)In: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 44, no 7, 74202- p.Article in journal (Refereed) Published
The lasing wavelength of a single-section distributed feedback (DFB) laser diode can be modulated by modulating the drive current. This makes it possible to utilize the DFB laser diode in a frequency-modulated continuous wave (FMCW) range and velocity measuring system. In FMCW, the frequency of the laser is ramped, and the frequency difference between the reflected wave and a local-oscillator wave is monitored. For maximum performance the frequency ramping should be linear. Due to thermal phenomena, a linear ramping of the current seldom results in a linear ramping of the optical frequency. We have derived a discrete thermal model, using resistors and capacitors, of our laser module. The thermal model was then used as a starting point to model the frequency behavior of the laser and to derive modulation currents that resulted in a linear frequency ramping at some different modulation frequencies.
Place, publisher, year, edition, pages
2005. Vol. 44, no 7, 74202- p.
Research subject Industrial Electronics
IdentifiersURN: urn:nbn:se:ltu:diva-8313DOI: 10.1117/1.1949205Local ID: 6d057470-5481-11db-9592-000ea68e967bOAI: oai:DiVA.org:ltu-8313DiVA: diva2:981205
Validerad; 2005; 20060913 (ysko)2016-09-292016-09-29Bibliographically approved