Abstract

Optical Frequency Domain Ranging (OFDR) is a well-known technique for contact-free distance measurements of high resolution and large dynamic range. Usually, a Michelson interferometer, operated with a frequency modulated (chirping) laser, is used to measure the difference of the lengths of both arms. The light reflected back from the target mirror of the measurement arm is superimposed to the light from the reference arm. In this way the detector at the output measures the frequency difference becoming an accurate measure of the path length difference. The faster the frequency chirping and the broader the chirp range are the better is the potential accuracy of the measurement. Therefore, Frequency Shifted Feedback (FSF) lasers with an inherent fast, wide and linear frequency chirp are attractive candidates to be used as light source for OFDR. Impressive results have already been reported using bulk and fiber FSF-lasers without and with phase-modulated seed [1, 2]. In this contribution we report the first demonstration of high resolution OFDR with an integrated tuneable Ti:Er:LiNb0₃ FSF-laser (λ_L ≈ 1550 nm). Even without seeding a resolution of up to 2.5 μm lias been achieved.

© 2007 IEEE