A fiber-optic rotation sensor for drill

This report describes a fiber-optic rotation sensor (FORS) particularly adapted to be placed adjacent a drill head to measure the orientation of a drill during or after drilling for minerals such as oil and gas. This kind of FORS is based on a Sagnac interferometer as ordinary FORS, but ordinary FORS can not satisfy the harsh environment of drilling. The report describes several technical ways to overcome the harsh environment: A quadrupolar winding for an optical sensing coil and the winding of optical fiber are potted within a matrix of adhesive material. Magnetic shield method is used. Optical power control, temperature holding technical and double temperature automatic control method is used. This kind of FORS can satisfy the need of drilling.