High-speed, low-threshold InGaAsP semi-insulating buried crescentlasers

摘要

The authors describe the refinement of this laser structure forhigh-speed operation and record bandwidths for a planar structure. Toachieve bandwidths in excess of 20 GHz, it is necessary to increase theslope of the resonance frequency vs. output power so that higherbandwidths are achieved at lower bias currents. This is accomplished byreducing the active channel width to 1 μm, by p-doping the activelayer, and by cleaving cavity lengths as short as 100 μm. Inaddition, the parasitic capacitance is further reduced by limiting thep-contact width to 12 μm, and by the use of a thick polyimide layerunder the bond pad metal. Lasers fabricated in this manner exhibitedthresholds as low as 6 mA, with maximum output powers of 15 mW per facetat 100 mA bias current. The total differential quantum efficiency wastypically 45-55%