An optical source includes a set of N light sources that provide a corresponding set of N optical signals having N carrier wavelengths. The method of forming the filters includes forming at least one piezoelectric filter structure comprising a plurality of electrodes formed to be in contact with at least one piezoelectric substrate. A temperature sensor can be disposed within the housing and a variable speed fan can be in flow communication with at least one of the first airflow path and the second airflow path. Exposed portions of the extrinsic a-Si layer and the intrinsic a-Si layer are removed, and then the photoresist and underlying portions of the extrinsic a-Si layer are removed. Rather than boot from an internal ROM coupled to the CPU, a boot loader is transferred by DMA from the first page of the flash mass storage block to an internal RAM.