Analysis of multi-wavelength photonic crystal single-defect laser arrays

Microcavities based upon 2-D photonic crystals (PhCs) can provide very high quality factors (Q) and strong confinement of light in small regions. This brings a significant enhancement in the spontaneous emission rate of the cavity mode, which then increases the spontaneous coupling factor and consequently allows the fabrication of low threshold lasers. However one of the main limitations is that single-defect cavities only produce very low output power, generally in the range of a few nWs and generally emit light at a single wavelength. One way to overcome this problem is to employ photonic crystal nanocavity laser arrays. A uniform array of single-defect cavities can produce multiple resonant peaks but with non-uniform spacing in wavelength spectrum and different peaks have significantly different Q factors. This paper demonstrates that square lattice single-defect cavity arrays based on pseudonoise (PN) sequences can provide multiwavelength spectrum with nearly uniform channel spacing and similar Q factors for different modes.