Relaxed fabrication tolerance for self-imaging photonic crystal waveguide splitters using a tapered multimode interference region

The power imbalance between different waveguide outputs is compensated by manipulating the dispersion of the guided propagation in the multimode interference (MMI) region. This is attainable using a tapered region at the beginning of the MMI region that has been verified through simulation and experiment. From this, the fabrication tolerance for the diameters of holes in a tapered 1 × 3 photonic crystal waveguide (PhCW) splitter is relaxed up to a range of at least 27nm. The output power is well-balanced to within 1 dB. The effective bandwidth of the splitters shifts only around 13nm, for a reduction of 10nm in the diameter of the PhCW holes. The optimized component is an outstanding ultracompact 1 × 3 splitter for the photonic integrated circuit (PIC). © 2011 Optical Society of America.