公开(公告)号：EP1400819B1

公开(公告)日：2009-05-20

申请号：EP02733242.8

申请日：2002-05-29

Applicant: Japan Science and Technology Agency

Inventor： YAMASHITA, Shinji ,  NASU, Yusuke

IPC: G02B6/02

CPC classification number: G02B6/02138 ,  G02B6/02085 ,  G02B6/02114 ,  G02B6/02152

Abstract: A super−structure/fiber/Bragg/grating is produced independently of a phase mask length. First, a beam is allowed to scan with the relative position between a mask and an optical fiber fixed (step 1). Then, the relative position between the mask and optical fiber is moved in the fiber’s length direction (step 2). And a beam is allowed to scan with the relative position between the mask and optical fiber fixed as in step 1. Next, the mask is removed and a uniform ultraviolet beam is applied to the optical fiber for the purpose of correcting and matching a phase shift to thereby be able to change a reflectance uniformly, whereby the optical length of that portion is chanced to provide a phase shift (step 3). A phase shift−imparting position may be any position except that between the both fixed positions. A phase shift amount is determined by a ultraviolet beam irradiation time (or light pulse number), and whether or not a necessary phase shift amount has been attained is determined while a reflection spectrum is being observed. The repetition of the above steps can produce an SSFBG of a free length.