Alignment-tolerant structures for ease of optoelectronic packaging

Expanded mode alignment tolerant optical structures will play an important role in low-cost, large-scale packaging of optoelectronic devices. In this paper, we present two expanded mode structures for operation at 1.55 micrometers . Our devices use single epitaxial growth and conventional fabrication schemes. High butt-coupling efficiencies (> 40%) to a single mode fiber with relaxed alignment tolerances were achieved. The first of our devices uses adiabatic transformation over 500 micrometers . The second device uses resonant coupling over a much shorter region of 200 micrometers . The second scheme offers an interesting possibility for monolithic integration of active-passive components. We present the design and simulation results of such an integrated device.