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Semiconductor optical gain

About: Semiconductor optical gain is a research topic. Over the lifetime, 5997 publications have been published within this topic receiving 96505 citations.


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Journal ArticleDOI
TL;DR: In this paper, the carrier distribution functions in a semiconductor crystal in the presence of a strong optical field are derived and expressions for the gain dependence on the carrier density and on the optical intensity are derived.
Abstract: The carrier distribution functions in a semiconductor crystal in the presence of a strong optical field are obtained. These are used to derive expressions for the gain dependence on the carrier density and on the optical intensity-the gain suppression effect. A general expression for high-order nonlinear gain coefficients is obtained. This formalism is used to describe the carrier and power dynamics in semiconductor lasers above and below threshold in the static and transient regimes. >

25 citations

Journal ArticleDOI
Paul Rees1, P. Blood1
TL;DR: In this article, the authors show that with a more exact implementation of spectral broadening thermal equilibrium is preserved and that the relationship between absorption and emission remains valid and discuss the accuracy of the measurements required to obtain a correct gain spectra.
Abstract: The use of detailed balance relationships between absorption and emission to obtain a gain spectrum from a spontaneous emission spectrum is a relatively easy method of measuring the gain from a semiconductor laser. It has been shown that the usual theoretical gain and emission spectra do not satisfy these relationships casting doubt on the validity of the procedure. We show that this arises from the incorrect implementation of spectral broadening that leads to a situation where the carriers and photons are no longer in thermal equilibrium and the relationship between absorption and gain in the calculations breaks down. We show that with a more exact implementation of spectral broadening thermal equilibrium is preserved and that the relationship between absorption and emission remains valid. We discuss the accuracy of the measurements required to obtain a correct gain spectra. >

25 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a summary of the advances in characterization techniques allowing comprehensive study of physical processes in semiconductor lasers, including optical gain, linewidth enhancement factor, transparency wavelength, optical loss and carrier life time.
Abstract: We present a summary of the advances in characterization techniques allowing comprehensive study of physical processes in semiconductor lasers. The studies of the electrical characteristics and optical emission below threshold allow to measure the optical gain, linewidth enhancement factor, transparency wavelength, optical loss and carrier life-time. Some other parameters, such as leakage current and wavelength chirp, can only be deduced from the above threshold measurements. Measurements of the carrier temperature and carrier heating in semiconductor lasers allow to obtain important information about the devices performance at high injection current densities. Taken together, all these measurements provide critical experimental feedback in the laser design process. They also furnish essential information to guide our understanding of the microscopic physical processes determining the laser performance and our efforts to simulate those processes.

25 citations

Journal ArticleDOI
TL;DR: A robust optical propagation model is derived that tracks the important peak gain shifts and broadening as long as the gain remains approximately parabolic over the relevant energy range in a running laser.
Abstract: Bulk and quantum well semiconductor lasers by nature display fundamentally different physical characteristics relative to multilevel gas and solid state lasers. In particular, the refractive index is nonzero at peak gain and the peak gain can shift strongly with varying carrier density or temperature. Moreover, a quantum well laser gain may be strongly asymmetric if more than the lowest subband is populated. Rigorously computed and experimentally validated, gain and refractive index spectra are now available for a variety of quantum well structures emitting from the infrared to the visible. Active devices can be designed and grown such that the gain spectrum remains approximately parabolic for carrier density variations typically encountered in above threshold pumped broad area edge-emitting semiconductor lasers. Under this assumption, we derive a robust optical propagation model that tracks the important peak gain shifts and broadening as long as the gain remains approximately parabolic over the relevant energy range in a running laser. We next derive a multimode model where the longitudinal modes are projected out of the total field. The next stage is to derive a mean-field single longitudinal mode model for a wide aperture semiconductor laser. The mean-field model allows for significant cavity losses and widely different facet reflectivities such as occurs with antireflection- and high-reflectivity-coated facets. The single mode mean-field model is further reduced using an asymptotic expansion of the relevant physical fields with respect to a small parameter. The end result is a complex semiconductor Swift-Hohenberg description of a single longitudinal mode wide aperture laser. The latter should provide a useful model for studying scientifically and technologically important lasers such as vertical cavity surface emitting semiconductor lasers.

25 citations

Journal ArticleDOI
TL;DR: In this paper, three dimensional features have been milled into optical materials by scanning a submicron focused gallium ion beam and different shapes are obtained using computer controlled beam placement and dwell time during sputtering.
Abstract: For the first generation of lightwave devices, semiconductor lasers and detectors have been used as discrete elements. As the technology continues to evolve, integration of light sources with electronics or other optical elements will be necessary. However, an efficient and reliable method for generating laser facets and other optical elements internal to the integrated system must first be developed. Three dimensional features have been milled into optical materials by scanning a submicron focused gallium ion beam. Different shapes are obtained using computer controlled beam placement and dwell time during sputtering. We have used this technique to create micron‐sized facets and reflectors in the active areas of semiconductor lasers. Light output and quantum efficiency measurements indicate that these features are of sufficient quality to fabricate monolithic integrated optical devices. Some of the applications currently being investigated are laser–detector pairs, coupled cavity lasers, lasers with inte...

25 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20233
20229
20211
20201
20187
201789