JPH0578801B

PURPOSE:To facilitate insertion into the extractor hole, etc., of an endoscope, to insert, detach, and to replace a laser surgical knife extremely easily by winding a coiled spring around the outer periphery of an optical fiber composed of a core and a clad which differ in refractive index from each other. CONSTITUTION:The coiled spring 42 is wound around the outer periphery of the fiber 26. The fiber 26 consists of the core 28 and the clad 30 which is made of quartz or a polymer and positioned at the outer periphery of the core, and the core and clad have mutually different refractive indexes. The clad 30 is coated with silicon, whose outer periphery is protected by a coating layer of nylon. The material of the coiled spring 42 uses a high strength steel wire, hard copper wire, stainless spring material, etc. When the coiled spring 42 is wound around the outer periphery of the optical fiber 26, a spring is wound around the optical fiber 26 and then the coiled spring 42 is wound around the fiber 26.