Fabrication technique for silicon-based optical subassemblies

Abstract

A novel optical subassembly arrangement is proposed. The subassembly comprises a silicon-based submount including a plurality of openings for placement of the various optical components utilized to form the optical subassembly. In particular, a silicon wafer is processed (e.g., etched) using conventional techniques to simultaneously form a large number of individual submounts, each submount processed to include a number of openings. The silicon processing may be sufficiently controlled such that active alignment of the components is minimized. An important feature of the design, when associated with an isolated embodiment, is that the silicon submount is formed to include openings for both the laser and isolator optics such that the openings are disposed along a thermal transport path through the silicon substrate from an attached thermoelectric cooler (TEC). Therefore, the laser and isolator optics are maintained at the same operating temperature. In one embodiment, the TEC may be attached to the underside of the substrate so as to form a cantilever arrangement with the substrate. In this embodiment, the isolator's magnet may be disposed to surround the substrate in a manner such that physical contact is avoided. The physical separation between the substrate and the magnet thus frees the TEC from having to unnecessarily cool the magnet.