Abstract

The small size of integrated optical components requires an OTDR system with resolution in the micrometer range. In this context two systems have been proposed: one employs a short coherence light source and interferometric detection,¹ the other uses ultrashort laser pulses and intensity correlation.² We describe a new OTDR system combining the advantages of both methods. The light source is a dye laser which delivers pulses of 300-fs duration tunable in wavelength between 1.25 and 1.35 μm. The backscattered light is measured with a Mach-Zehnder-type interferometer in conjunction with balanced heterodyne detection. The sensitivity of the system is better than 100 dB, and the standard resolution is 60 μm in air. Taking advantage of the large tuning range of the dye laser the resolution can be improved to <10 μm. We show the applicability of the system for investigations of integrated optical devices. Such an OTDR system capable of the diagnostics of optical waveguide structures is of potential use for further progress in the field of integrated optics.

© 1988 Optical Society of America