Manuel Leones

Analysis of the dynamic behavior and short-pulse modulation scheme for laterally coupled diode lasers

A theoretical investigation of the high-speed coupling phenomena of two laterally coupled diode lasers (LCDL) is presented. The analysis is centered on the spatiotemporal dynamics of the LCDL when coupling between emitters is varied, We have obtained the dynamic behavior of these devices showing high resonance frequencies beyond the well-known resonance frequency of a single diode laser. In this paper, we have presented a new modulation scheme by asymmetric switching of the injected current in both stripes, showing short optical output pulse modulation with a high repetition rate.

COUPLING EFFECTS IN THE DYNAMIC BEHAVIOR OF TWO LATERALLY COUPLED SEMICONDUCTOR LASERS

In this work we present a study of the dynamic behavior and main characteristics of a two laterally coupled semiconductor laser arrays by numerical analysis. Laterally coupled semiconductor laser arrays are complex laser structures that have great interest due to their small size, compact, high-speed modulation and high power-emission. We present a study of the parameters that affect the dynamic behavior of the lateral coupled semiconductor laser arrays described by a rate equation model.

Experimental characterization and analysis of the static behavior of twin-ridge AlGaInAs laterally coupled lasers (LCDL)

Laterally coupled diode lasers emitting at 1.3 um are presented. Devices were fabricated with distances between ridges varying from 2.76 um to 8.32 um. Electronic coupling effects are investigated by individually varying the currents in each ridge while monitoring output power. It is observed that for devices with 8.32 um separation between ridges there is minimal current sharing, whereas for 2.76 um separation there is considerable current sharing. Optical coupling is measured via the far-field, where most devices show out-of-phase locking, although in-phase locking is observed in a minority of cases. Devices therefore show conditions necessary for the observation of high speed dynamics.

Modeling of the static behavior in two InGaAsP laterally coupled semiconductor diode lasers

This paper presents our initial work on high speed laterally coupled semiconductor diode lasers, where the structures to be studied will be two laterally coupled semiconductor diode lasers are expected to increase the modulation bandwidth by using the principles of coupling. We will show a study of the modeling used to find the static and spatial behavior of theses devices, obtaining the near and far field profiles and light power-current characteristic. Our primary goal will be to present the static and spatial behavior of the two InGaAsP laterally coupled semiconductor diode lasers using the effective-index method and Beam Propagation Method (BPM). Our results provide the static evolution of the current density profile, carrier density in the active layer and effective index shape at different injection current levels of a specific InGaAsP structure operating at 1.3 micrometer.

Regimes of nonlinear behavior in a laterally coupled laser diode

Laterally coupled laser diodes are devices in which several lasing stripes are laid side to side, allowing light from one emitter to couple into its neighboring ones. Coupling has been found to cause serious disadvantages such as turning the laser arrays into intrinsically unstable devices. In this paper we show that coupling is also responsible for some unique features that can be used to generate short pulses.

Spatio-temporal study of controlled high-speed modulation in two laterally coupled lasers (TLCL)

A theoretical study of the control of the high-speed modulation of Two Laterally-Coupled Lasers (TLCL) is presented. The analysis is centered on the spatio-temporal dynamics of the TLCL when strength coupling between emitters is varied, depending of the distance between emitters and the carrier diffusion level. We have controlled the high-speed chaotic dynamics through the injection current, studying the temporal evolution of the relative phase between the fields of the two stripes. After controlling the high-speed dynamics, we have obtained a modulation scheme by asymmetric switching of the injected current in both stripes, which gives an output pulse modulation with a high repetition rate.

Influence of the design parameters in the spatiotemporal dynamics of two InGaAsP laterally coupled semiconductor lasers

This paper presents a work on spatiotemporal behavior and study of design parameters for two laterally coupled semiconductor diode lasers. The structures to be studied are Two Laterally Coupled semiconductor diode Lasers (TLCL) to 1,3um and they are expected to increase the modulation bandwidth to two or three times the modulation bandwidth for a single semiconductor laser, by using the principles of coupling between emitters. We show a study of the modeling used to find the spatiotemporal behavior of these devices when we change some design parameters, which are very important if we want to obtain a high-speed modulation control by current injection, because these devices can present unstable dynamics depending on coupling level. Temporal evolution of the Near-field, Far-field, photon and carrier densities and the phase between the fields inside the two lasers are used to study the dynamic behavior of the TLCL when we change parameters as the distance between emitters, carrier diffusion, current spreading and the level of injected current.

Synthesis of digital gain filters for spectrum analysis in semiconductor lasers

In this paper, modeling of semiconductor diode lasers by sampling the cavity of the laser using digital techniques is presented. These models, that sample the cavity of the semiconductor laser simulating the spread of the field in the active zone, are the only methods that permit evaluation of the spectral behavior of the device. Throughout this work, we present the study of the temporary evolution of the spectrum of the longitudinal modes of a semiconductor laser by using digital simulation techniques. Due to the digital nature of the filter and algorithm, we can adjust any given frequency response and reduce CPU time in computing the results. We present two digital models, DLM and LDDM, which improve the behavior of the traditional methods used in order to obtain temporary spectral response of semiconductor laser diodes.

Modeling of semiconductor lasers by multisection digital analysis

This work presents a model for semiconductor lasers based on digital signal analysis. This model discretizes the laser cavity, sampling the electrical field along the longitudinal direction of the cavity at fixed space intervals. The discretization of the field allows us to obtain the longitudinal spectrum of the laser. For computational efficiency, the wavelength dependence of the material gain is implemented using digital filters applied to the field samples, lumped into a single cavity. Therefore, the most complex and computationally costly operation of the algorithm is performed in a single section. Even further, due to the digital nature of the filter, we can adjust any given frequency response both in modulus and phase using the theory of discrete time signal analysis. The results of this model are compared versus standard modeling methods such as integration of the rate equations with Runge-Kutta Algorithm.

Stabilization in an optical fiber interferometer using a semiconductor laser

In this paper we present results of our stabilization scheme for an optical fiber Mach-Zehnder interferometer with a diode laser as light source. It is developed for compensating the drift path difference produced by external parameters as the environmental temperature. The optoelectronic setup in which the interference signal is fed back to the injection current of the laser diode is investigated in order to obtain a stabilized system. Details on parameter characterization, system design and the results observed are given.