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1995
Conference Paper
Titel
Beam propagation model of tapered amplifiers including non-linear gain and carrier diffusion
Alternative
Beam propagation Modell von Trapezverstärkern mit Berücksichtigung von nichtlinearem Gewinn und Ladungsträger-Diffusion
Abstract
Recent interest in high-power single-mode diode lasers has led to the evaluation of a variety of semiconductor amplifier geometry's (1), integrated master oscillator power amplifier (MOPA), designs and flared oscillator devices. Flared amplifiers and oscillators have been found to be less sensitive to filamentation effects than broad area devices, although filamentation still ultimately limits the performance of such devices (2). Using a FD-BPM model we investigate the performance to be expected from various flared laser structures in terms of both output power and beam quality. We clarify the influence of such material parameters as the number of quantum wells, the differential quantum efficiency and the linewidth enhancement factor on the output beam profile of the amplifier. We point out the influence of the linewidth enhancement factor showing that a reduction of this factor improves the output beam quality, the resistance to inhomogeneous injection, and the output farfield. Furthe rmore, a simulation of a 2D integrated elliptical lens is presented, showing the possibility of 'on chip' correction of the astigmatism for low alpha-factor structures. Such a lens would spare the use of an external cylindrical lens for collimation of the output signal. Based on arsenides, phosphides and more recently also on nitrides and antimonides the portfolio of III-V semiconductor devices is large. Solid solution and heterostructuring enable high versatility in electronic and optoelectronic characteristics. Lattice matched, pseudomorphic, metamorphic HEMTs, HBTs with tunneling emitters, resonant tunneling diodes (RTDs) with large peak-to-valley ratios, high-modulation, tunable and surface emitting laser diodes, high-power diode lasers, MSM and PIN photodiodes, quantum well infrared photodiodes (OWIPs), blue emitters, highbrightness LEDs, SEED and VSTEP devices are basic constituents of microwave/mm-wave, optoelectronic and high speed/low power consuption components which enable novel system realizations not possible before. Applicability of III-V devices depends on the ease of interplaying with a silicon world, their integratability to ICs of higher functionality as well as on reliability and cost-effective manufacturing.