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External-cavity semiconductor laser sensor

Quan, OL and Seng, YT and Lan, LP and Wah, JT and Sabaratnam, Andrew T and Hegde, Gopalkrishna M and Selvarajan, Ananth (1999) External-cavity semiconductor laser sensor. In: SPIE Conference on Advanced Photonic Sensors and Applications, Tuesday 30 November 1999, Singapore, Singapore.

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The spectral characteristics of a diode laser are significantly affected due to interference caused between the laser diode output and the optical feedback in the external-cavity. This optical feedback effect is of practical use for linewidth reduction, tuning or for sensing applications. A sensor based on this effect is attractive due to its simplicity, low cost and compactness. This optical sensor has been used so far, in different configuration such as for sensing displacement induced by different parameters. In this paper we report a compact optical sensor consisting of a semiconductor laser coupled to an external cavity. Theoretical analysis of the self- mixing interference for optical sensing applications is given for moderate optical feedback case. A comparison is made with our experimental observations. Experimental results are in good agreement with the simulated power modulation based on self-mixing interference theory. Displacements as small as 10-4 nm have been measured using this sensor. The developed sensor showed a fringe sensitivity of one fringe per 400nm displacement for reflector distance of around 10cms. The sensor has also been tested for magnetic field and temperature induced displacement measurements.

Item Type: Conference Paper
Publisher: SPIE--The International Society for Optical Engineering
Additional Information: Copyright of this article belongs to SPIE--The International Society for Optical Engineering.
Department/Centre: Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited: 16 Mar 2012 08:49
Last Modified: 16 Mar 2012 08:49
URI: http://eprints.iisc.ac.in/id/eprint/43908

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