Abstract: An example system for downhole measurement disclosed herein comprises a tool to be positioned downhole in a formation, the tool comprising an imaging system to determine measurement information from imaging information obtained by sensing light, and an illumination system to control source light to be emitted by the tool. The system also comprises an optical cable to sense an optical field of view that is remote from the tool, the optical cable including an optical fiber bundle comprising a bundle of imaging fibers to convey the imaging information from a sensing end of the optical cable to the imaging system, and a plurality of illumination fibers positioned outside the bundle of imaging fibers, the illumination fibers to convey the source light from the tool to the sensing end of the cable, the illumination fibers to emit the source light to illuminate the optical field of view.

Abstract: An example system for downhole measurement disclosed herein comprises a tool to be positioned downhole in a formation, the tool comprising an imaging system to determine measurement information from imaging information obtained by sensing light, and an illumination system to control source light to be emitted by the tool. The system also comprises an optical cable to sense an optical field of view that is remote from the tool, the optical cable including an optical fiber bundle comprising a bundle of imaging fibers to convey the imaging information from a sensing end of the optical cable to the imaging system, and a plurality of illumination fibers positioned outside the bundle of imaging fibers, the illumination fibers to convey the source light from the tool to the sensing end of the cable, the illumination fibers to emit the source light to illuminate the optical field of view.

Abstract: The objective of the present invention is to provide a solution for detecting timeslot conflict between Optical Network Units (ONUs) in an Optical Line Terminal (OLT). When all ONUs are deactivated and there is still any light signal in the upstream, each ONU is notified to switch off the power supply of its transmitter one by one to detect whether there is any failure ONU; when all ONUs are deactivated and there is no light signal in the upstream, the failed ONU can be located through ranging the ONUs separately. The solution can be implemented through software update, without affecting the intrinsic hardware design.