| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To suppress the 0th-order light component transmitting without diffracted to the minimum and to prevent noises in the reflection spectrum of a transferred optical waveguide grating. <P>SOLUTION: The phase mask 21 has a grating type pattern with repetition of recessed grooves 26 and projections 27 having a square cross section on one surface of a transparent substrate, and is used to form a grating in an optical waveguide 22 by interference fringes of diffracted light of UV exposure light 23 by the repeated pattern. The phase mask 21 is constituted in such a manner that the cross sectional dimensions of the repeated pattern of the recessed grooves 26 and the projections 27 satisfy the relation of d/d<SB>0</SB>≥1.03 and f≤0.48, wherein d is the groove depth of the recessed groove, w is the width of the projection,Λis the period of repetition,λis the exposure wavelength, n<SB>2</SB>is the refractive index of the transparent substrate, n<SB>1</SB>is the refractive index of the atmosphere, d<SB>0</SB>is defined by d<SB>0</SB>=λ/ä2(n<SB>2</SB>-n<SB>1</SB>)}, and f is defined by f=w/Λ. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
