A high speed low capacitance laser structure for integration

A laser structure for use at microwave frequencies that has reduced parasitic capacitance and resistance and is suitable for integration with other optoelectronic components is described. The fabrication of two devices is discussed: a 1.3- mu m bulk device with a liquid-phase epitaxy (LPE)-grown active region and an all metalorganic vapor phase epitaxy (MOVPE) 1.55- mu m multiple-quantum-well distributed feedback (DFB) laser. The devices were bonded active side up onto metal carriers for assessment with connections being made using short bond wires to a microstrip line terminated in a 50- Omega load and fed by a shape memory alloy (SMA) launcher. Measurements of light-current characteristics showed threshold currents of 15 mA for 250- mu m-long uncoated lasers and external differential quantum efficiencies up to 25% facet at 25 degrees C for the 1.3- mu m devices. The results of large- and small-signal measurements of the lasers are presented.<
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