| 摘要 |
PURPOSE: To correct an error based on an algorithm operation by optical monitoring signals at the time of filter sticking by maintaining the product of an average refractive index and the thickness of the sine cycle of a component so as to accurately achieve Bragg reflection conditions. CONSTITUTION: A dotted line 200 is corrected by a correcting action performed by algorithm to a refractive index profile (solid line 202) provided with the error. The correction of vertical (V of 104) and horizontal (H of 102) index profiles is continuously optically monitored, plural medium profiles generated in terms of a sine measure the increase of optical thickness and completely and accurately match it with the increase of the optical thickness of an ideal target. A processing during continuation is adjusted corresponding to an alternative sequence (algorithm) incorporated in a program beforehand and the optical thickness signals make the sine sticking of an optical medium be accurate. Thus, horizontal H and vertical V index profile correction treatments are both performed.
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