| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent manufacture of a defective optical multiplexer/ demultiplexer by discriminating between normal and defective products after processing a substrate and evading the mixing of different filter tips. <P>SOLUTION: Product information is written on a multilayer optical filter provided with a dielectric multilayer in which a plurality of high refractive index films and low refractive index films are alternately layered. The multilayer optical filter is used which is characterized in that the product information is written on the formed film surface of the dielectric multilayer of the multilayer optical filter, and the product information includes at least one of a product lot number, an address in wafer, product specifications, and product history. <P>COPYRIGHT: (C)2003,JPO</p> |
