We propose a large-scale variable delay line based on planar light-wave circuit technology and its application as a reference arm in an optical low-coherence reflectometer. This variable delay line is composed of 16 asymmetrical delay arm pairs sandwiched between 2 optical switches, which select the path for a needed delay. This configuration enables us to eliminate the need for a moving part in the reflectometer. We can scan the reference arm over a length of 262.1 mm with a step of less than 1.0 µm in air and achieve reflectometer sensitivity of about −47 dB.
© 2005 Optical Society of America
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(130.3120) Integrated optics : Integrated optics devices
(130.6010) Integrated optics : Sensors
(230.7390) Optical devices : Waveguides, planar
K. Takiguchi, M. Itoh, and H. Takahashi, "Integrated-optic variable delay line and its application to a low-coherence reflectometer," Opt. Lett. 30, 2739-2741 (2005)