Fabrication of ultracompact 3-dB 2 x 2 MMI power splitters

Recently proposed tapered MMI devices have been shown to allow for substantial reductions in device geometries, but as of this time such ultracompact devices have not been realized. The fabrication and testing of a series of parabolically tapered 3-dB 2/spl times/2 MMI devices have been accomplished in the InP-InGaAsP double heterostructure system. The results validate previous predictions and yield device geometries about 40% smaller than the shortest previous 3-dB 2/spl times/2 MMI device. The measured splitting ratios of these devices are compared to the results of numerous beam propagation method simulations, based on the finite-difference method, and good correlation is obtained.