Copper or a copper alloy is removed by chemical-mechanical planarization in a slurry of an oxidizer, an oxidation inhibitor, and an additive that appreciably regulates copper complexing with the oxidation inhibitor. A header table may be maintained at the transmitting end whereby headers are stored in table entries based on a table index generated from a hash function applied to the headers. The conductive traces are formed on the first and third sides and adjoining edge of the submount by a process that uses a shadow mask. At least one optical component is provided between at least one pair of the four reflective elements.