RESOLUTION-CONTROLLABLE OPTICAL-TIME DOMAIN REFLECTOMETRY BASED ON LOW COHERENCE INTERFERENCE

A low coherence OTDR that can control spatial resolution is proposed to efficiently diagnose waveguides. This is achieved by proposing a new light source consisting of an SLD, an optical bandpass filter for truncating the SLD output, and an AR-coated LD booster amplifier. The spatial resolution is determined by the bandwidth of the filter. Two resolutions, 44 and 14-mu-m, are experimentally demonstrated with and without the filter having a 2.7-nm FWHM, respectively. The length of the blind space and the minimum detectable reflectivity are respectively < 7 mm and < -134 dB at a 3-Hz detection bandwidth, for both resolutions. The noise characteristics of the light source and the system performance are investigated theoretically and experimentally.