摘要 |
A method for producing a lambda /4 shift type diffraction grating by producing a diffraction grating pattern on a substrate with a material capable of being selectively etched relative to the substrate, depositing a resist to bury the diffraction grating pattern, removing a portion of the resist to expose at least a portion of the surface of the diffraction grating pattern, removing the diffraction grating pattern on a first portion of the substrate, etching the first portion of the substrate using the remaining resist pattern as a mask, and etching a second portion of the substrate adjacent to the first portion using the remaining diffraction grating pattern on the second portion of the substrate, thereby producing a lambda /4 shift type diffraction grating having a lambda /4 phase shift region at the junction of the first and second portions of the substrate.
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