Optical fiber grating, optical fiber grating manufacturing method, and optical fiber grating manufacturing apparatus

Abstract

The invention provides a method and apparatus that precisely and efficiently improves the optical properties of an optical fiber grating. Preferably hydrogen loading processing, grating formation processing that forms a grating part by irradiation with ultraviolet light at a predetermined period, and preferably dehydrogenation, adjusting the optical properties by a suitable combination of uniform ultraviolet irradiation processing that irradiates the grating part as a whole with ultraviolet light and heat trimming processing, and finally heat aging is carried out.

Description

[0001] This application claims priority of a prior application Ser. No. 09 / 929,934, filed Aug. 15, 2001BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a manufacturing method for an optical fiber grating used in an optical communication system (hereinbelow, referred to simply as an “optical fiber grating), and in particular, an optical fiber grating, a manufacturing method for the same, and a manufacturing apparatus for the same that allows fine adjustment of the optical properties of the optical fiber grating, and greatly improves the manufacturing yield. [0004] 2. Description of the Related Art [0005] An optical fiber grating is a device having the property of attenuating the light of a specific frequency by coupling it in a reflection mode, a cladding mode, or a radiation mode. A type that couples the light of a specific wavelength with the cladding mode or radiation mode in the same direction as the incident light is called a t...

AI Technical Summary

Benefits of technology

[0023] In order to resolve the above-described problems, in the present invention, the following resolution device is proposed. According to the optical fiber grating manufacturing method of the present invention, the uniform ultraviolet irradiation processing and the heat processing are carried out in a suitable combination, and thereby, the central wavelength of the optical fiber grating and the rejection ratio at the central wavelength can be adjusted, and an optical fiber grating having the target optical properties can be obtained.

[0024] A first aspect of the present invention is a manufacturing method for an optical fiber grating comprising the steps of: forming a grating part having a periodic refractive index distribution by irradiating an optical fiber along the longitudinal direction by ultraviolet light at a predetermined period and carrying out dehydrogenation when necessary; carrying out at least one time uniform ultraviolet irradiation processing that irradiates the grating part as a whole with ultraviolet light; and carrying out heat aging in order to stabilize the optical properties of the grating part.

[0032] According to the optical fiber grating apparatus of the present invention, the optical properties of the optical fiber grating are measured, and depending on the results of this measurement, suitable ultraviolet irradiation processing and heat processing can be easily carried out. In addition, the tension of the optical fiber can be maintained at a suitable constant by a tension maintaining mechanism provided on the fiber clamp, and thereby modulation or fluctuation of the optical propertied due to insufficient or excess tension or changes in the tension can be prevented, and precise control of the optical properties becomes possible.

Problems solved by technology

Therefore, if only the central wavelength is of concern, it can be controlled comparatively stably, but there is no adjustment mechanism for the rejection ratio, and while the optical properties of the product can be stably maintained, there is difficulty in guaranteeing a high yield.

In addition, the change of the refractive index of the optical fiber grating is sensitive to the heat environment (that is, thermal instability) particularly after ultraviolet irradiation, and stably maintaining the stability of the optical properties in this environment over the long term is difficult.

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