<title>Measurement system for scattering medium by synthesis of coherence function with superstructure grating distributed Bragg reflector laser diode</title>

Abstract

The application of the technique of synthesis of optical coherence function for detection in scattering medium is investigated. By modulating the optical frequency, the technique synthesizes the coherence function into a delta-function-like peak at an arbitrary location, and thus can detect interferometrically the information at that location. The location is adjustable by the modulation parameter or additional phase modulation. A multi-section super-structure grating distributed Bragg reflector laser diode (SSG-DBR-LD) of THz-order tunable range is employed to enhance the spatial resolution for suppressing the multiple scattering from locations other than that detected. In a primary experimental demonstration, a reflectometry of 550 tm spatial resolution has been built up and was used to detect scattering medium.