In this work we investigate the influence of extractor design and temperature on transport properties of quantum
cascade detector. For this purpose we realize numerical calculation of electron lifetimes considering electronphonon
and electron impurities scattering. Electron-phonon interactions are treated using Fermi Golden Rule
which allows to calculate lifetime of carriers with temperature and structure design taking into account. Transport
characteristics of the quantum cascade detectors have been computed using density matrix theory. As a result, we
have obtained the system of ordinary differential equations describing dynamics of electron distribution functions
and intersubband correlations. Managing carrier lifetime in quantum wells gives us possibility to control quantum
efficiency and response.
The thermal dependence of mirror reflective properties in oxide-confined VCSEL is investigated. The temperature
distribution over the cavity versus applied current is calculated. The refractive indexes of the mirror layers are redefined by
using the temperature coefficients, and changes in radial reflectance spectra of the mirror are analyzed. Results show a shift
of stopband and Bragg wavelength DBR as well as shift of laser operation wavelength at different injection currents and the
formation of the temperature lens in the mirror due to decreasing the temperature close to edge of oxide windows.
This work presents complete 2D electro-opto-thermal simulation of the intracavity contacted oxide confined vertical
cavity surface emitting lasers (ICOC VCSEL). The analysis represents the influence of geometrical parameters on power and modulation properties on such devices. The optimized values with maximum of modulation bandwidth are
Self-consistent computations of the potential profile in complex semiconductor heterostructures can be successfully applied for comprehensive simulation of the gain and the absorption spectra, for the analysis of the capture, escape, tunneling, recombination, and relaxation phenomena and as a consequence it can be used for studying dynamical behavior of semiconductor lasers and amplifiers. However, many authors use non-entirely correct ways for the application of the method. In this paper the versatile model is proposed for the investigation, optimization, and the control of parameters of the semiconductor lasers and optical amplifiers which may be employed for the creation of new generations of the high-density photonic systems for the information processing and data transfer, follower and security arrangements. The model is based on the coupled Schrödinger, Poisson's and drift-diffusion equations which allow to determine energy quantization levels and wave functions of charge carriers, take into account built-in fields, and to investigate doped MQW structures and those under external electric fields influence. In the paper the methodology of computer realization based on our model is described. Boundary conditions for each equation and consideration of the convergence for the method are included. Frequently encountered in practice approaches and errors of self-consistent computations are described. Domains of applicability of the main approaches are estimated. Application examples of the method are given. Some of regularities of the results which were discovered by using self-consistent method are discussed. Design recommendations for structure optimization in respect to managing some parameters of AMQW structures are given.
A numerical model for the investigation of the ultrafast gain properties in asymmetrical multiple quantum-well semi-conductor optical amplifiers (AMQW SOAs) has been developed considering propagation of ultrashort optical pulses with different wavelengths. The dynamics of the number of carriers and carrier temperature are investigated for each quantum well. The results agree with the experimental results of pump probe measurements with different wavelengths. It is shown that gain recovery is slower for higher energy wells for pump signals of all wavelengths.
The semiconductor laser is commonly used as a light source in fiber-optical telecommunication systems. In order to send as much information as possible in a short time, it is important that the laser has a large modulation bandwidth, i.e., the turn-on and turn-off time should be as short as possible. In analogue fiber optic systems for transmission of radio or television signals, it is also important that the light from the laser increases linearly with driving current even at high modulation frequencies. Otherwise, the transmitted signal will become distorted. The modulation bandwidth and the modulation distortion are dependent both on the laser structure and the gain characteristics of the active material. One of the most useful approaches for the time-domain description of the response of optoelectronic devices is the so-called "rate equation model," which has been widely used to describe laser performance. Commonly, laser models with simple gain expressions are used for simulation of laser dynamics. In these models the small-signal dynamic parameters like the differential gain and gain saturation parameter are extracted from modulation response measurements. However, we show that in order to correctly calculate distortion, an accurate model of the dependence of gain on carrier density, <i>n</i>, and photon density, <i>s</i>, is needed. Commonly used gain models, fitted to give exactly the same modulation response can give significantly different distortion behavior.
Results of numerical investigation of transversal cavity mode influence on static and dynamic characteristics of oxide-confined vertical-cavity surface emitting laser are presented and discussed. It was shown that mode selection could improve modulation properties of laser. Instigated the influence of injection current on near field distribution and spatial hole burning effect.