| 摘要 |
The invention relates to an exposure method for producing a Bragg grating on a photosensitive guide (120) or optical fiber (120), in which method the guide (the fiber) (120) is scanned by a light beam (300) and means (100, 220, 230) are provided for modulating the exposure time along the guide (the fiber) by varying the speed at which the beam (300) moves along the guide (the fiber) (120) so that it is located opposite each location of the guide (the fiber) (120) for a time period that varies with the location, the method including the step of disposing in front of the guide (the fiber) (110) a system (140) adapted to create interference fringes on the guide (the fiber) (120) and to scan the beam (300) over the interference system (140) at a speed that is modulated along the system (140), and furthermore the step of having the beam scan the guide (the fiber) (120) at a modulated speed without the interference system (140) on the path of the beam (300), the scanning with the interference system (140) being effected with modulation of the exposure time increasing the exposure time in the central part of the guide (the fiber) (120) and the scanning without the interference system being effected with modulation of the exposure time reducing the exposure time in the central part of the guide (the fiber) (120).
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