Temperature dependent efficiency and modulation characteristics of Al-free 980-nm laser diodes

Temperature dependent efficiency and modulation characteristics of strained quantum-well (QW) InGaAs-InGaAsP-InGaP 980-nm laser diodes of various designs are analyzed using self consistent carrier transport analysis including stimulated emission. The decrease of the differential efficiency of 980-nm laser diodes with temperature is found to be caused by an increased modal loss attributed to the free carrier (electron and hole) absorption. The obtained results agree well with experimentally observed increase of internal loss at higher temperatures. Modulation characteristics are determined mainly by drift-diffusion in separate confinement region along with processes of carrier capture and escape in QWs. At high temperatures modulation bandwidth is reduced because of the decrease in differential gain. Graded index separate confinement heterostructure and multi-QW lasers show superior efficiency and modulation behavior at high temperatures.<
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