Abstract: An optical fiber component comprises an optical element (1), a pair of PhC fibers (2a, 2b) with a large MFD (approximately 30 to 50 ?m), and a pair of SM fibers (3a, 3b) with a small MFD (approximately 10 ?m). The pair of the PhC fibers (2a, 2b) has cores (21a, 21b) for transmitting light and clads (22a, 22b) provided on the outer periphery of the cores (21a, 21b). An output end of a first PhC fiber (2a) is optically connected to a light incident end-face (1a) of the optical element (1) with the first PhC fiber output-end aligned with the optical axis of the optical element (1). An input end of a second PhC fiber (2b) is optically connected to a light exit end-face (1b) with the second Phc fiber input end aligned with the optical axis of the optical element (1). An output end of a first SM fiber (3a) is optically connected to the input end of the first PhC fiber (2a) with the first SM fiber output-end aligned with the optical axis of the first PhC fiber.

Abstract: It is an object of the present invention to provide an optical fiber for transmitting ultraviolet ray which has an improve transmittance and is prevented from deterioration by ultraviolet ray with which it is irradiated. It is another object of the present invention to provide an optical fiber probe which can propagate vacuum ultraviolet ray and deep ultraviolet ray at a high transmittance, is deteriorated only to a limited extent when irradiated with ultraviolet ray and can be etched to have a desired shape of the sharpened section at the fiber end. The present invention provides the optical fiber for transmitting ultraviolet ray which has a core 5 of silica glass containing a given content of fluorine and a clad 6a of silica glass containing a given content of fluorine or boron, a clad 6b of a resin which transmits ultraviolet ray or a clad 6c having air holes H. The clad may be coated with a protective layer and further with a covered layer for protection.