ECE227A_final_solutions_final - Final ECE 227A December 8,...

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Final ECE 227A December 8, 2010 Department of Electrical and Computer Engineering University of California, Santa Barbara # Students 6 5 4 3 2 1 <50 51-60 61-70 71-80 81-100 # Students 7 6 5 4 3 2 1 B B+ A- A Name_______________________________________
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2 (35 pts) 1. A vertical cavity surface emitting laser design for operation at 1300 nm is shown in Figure 1. The laser needs to have AlAsSb/GaAlAsSb DBR mirrors, lattice matched to the InP substrate. A one wavelength cavity is used with InP intracavity contact/heat-spreaders on the edges, and an undoped InP region in the center that contains 5 InGaAs quantum wells. The quantum wells are 8 nm thick, and the barriers are 12 nm thick. The refractive index for the quantum wells is 3.55. For the DBR mirrors, assume index values of 3.00 and 3.30 for the AlAsSb and GaAlAsSb layers respectively (at 1300 nm). The metal-backed top mirror is assumed to have an amplitude reflectivity of 0.9979 (including mirror loss). The internal losses in the DBRs and the cavity region are assumed to be 18 cm -1 . The injection efficiency is measured to be 75%. 8 um diameter etched pillar VCSELs are formed, and the optical and carrier losses due to the aperture and pillar walls can be neglected. The effective index of the mode is 3.2. The light is measured through a 300 μ m thick InP substrate whose incremental propagation loss is 7 cm -1 . The substrate is AR coated on the bottom. a.
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ECE227A_final_solutions_final - Final ECE 227A December 8,...

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