Millett, R., Schriemer, H., Hall, T. et al. Opt Quant Electron (2008) 40: 1239. doi:10.1007/s11082-009-9293-2
We demonstrate the results of an analysis of laterally coupled distributed feedback (LC-DFB) lasers with higher order gratings, including the effects of radiating partial waves. For a given fabrication resolution, first-order gratings, if they can be reliably manufactured, always provide the strongest coupling. However, at resolutions requiring higher order gratings, if duty cycles of >0.5 are used, the lowest grating order is not always the one with the strongest coupling. An analysis of the rounding of the grating teeth showed that the required threshold gain was increased by nearly 20% when the rectangular grating was rounded in fabrication.
Distributed feedback lasers Coupled-mode theory Higher order gratings