Thermally tuned external cavity laser with micromachined silicon etalons: design, process and reliability

A broadly tunable external cavity laser, employing thermally tuned etalons and laser-welding manufacturing is presented. The design of the tunable laser module is based on the quasi-planar manufacturing technology that is used for multiple other Intel products such as 10 Gb/s transponders and transceivers for Sonet and Ethernet applications. The laser cavity is defined at the output end by the gain chip facet and by an external mirror at the other end. An intracavity filter comprises two micromachined thermally-tuned silicon etalons manufactured to have slightly different free spectral ranges. The output optics of the external cavity laser are similar to those found in single-channel lasers. The density of optical components and the alignment precision required presented challenges for the development of scalable component placement processes and packaging. However, excellent performance has been obtained as evidenced by short-term stability under thermal and mechanical stress tests and long-term stability under accelerated stress tests.