| 摘要 |
A grating structure (26, 26a, 36, 46, 66) useful for WDM multiplexer/demultiplexer applications is described. The grating structure (26, 26a, 36, 46, 66) has a substantially polarization-independant diffraction efficiency over a predetermined useful wavelength range, for example, between 1.4 and 1.6 mu m. Each grating period includes a triangular section (72, 92) and a flat-topped section (76, 96), with the width of the flat-topped section (76, 96) between 20 and 50% of the grating period. The disclosed grating structure can be formed in any material that is substantially transparent over the useful wavelength range and used in either a Littrow and a Littman-Metcalf configuration. |
