Pdf an analysis of cleaved coupledcavity lasers researchgate. T present, the external cavity semiconductor laser is a feasible means to realize a singlefrequency semi conductor laser. Optical bistability in semiconductor lasers is an interesting subject because of their many advantages. Semiconductor ring lasers are literally ringshaped optical waveguides with a lasing medium. Employing the center manifold theorem and normal form method, an algorithm is derived for determining the. Light is emitted at a junction between two regions of opposite doping as shown in gure 4. Osa wavelength switchable semiconductor laser using half. A distinctive discussion of the nonlinear dynamical phenomena of semiconductor lasers. How semiconductor laser is made material, making, history. Vertical cavity surface emitting lasers vcsel, on the other hand, have a large gain saturation. Fang abstract in this report, a model of external cavity semiconductor laser is built, and then based on this model a program is coded for simulating the thermally induced wavelength shift and mode hopping.
N the world of semiconductor lasers, coupledcavity lasers are of interest for two reasons. On the other hand, although semiconductor laser with the fabryperot cavity type is preferential in costeffective optical systems, its emission spectral width can be quite broad 1 thz. Optical bistability in coupledcavity semiconductor lasers. Rp photonics encyclopedia semiconductor lasers, laser diodes. The pump laser is resonantly coupled into a cavity where 20 mm long periodically poled ktp 17 nonlinear crystals are set so to satisfy quasi phasematching for degenerate frequency downconversion opo, and sum frequency generation between the pump and. Coupled cavity dqw semiconductor lasers sciencedirect. The conventional semiconductor laser consists of a compound semiconductor, gallium arsenide.
This is the first book on tunable external cavity semiconductor diode lasers, providing an uptodate survey on the physics, technology, and performance of widely applicable coherent radiation sources of tunable external cavity diode lasers. Analysis of broadly tunable coupledcavity semiconductor lasers. The coupled cavity modes have a larger mode spacing of 0. External cavity laser diodes fibrecoupled laser diodes. Dashed lines indicate threshold gains of the indi vidual lasers in the absence of coupling. Coupled cavity effects has been observed in the electroluminescence spectra of monolithic gaasgaalas double quantum well graded index separate confinement heterostructure semiconductor diode lasers. Laterally coupledcavity semiconductor lasers caltech authors. They are used in optical communication and fibre sensor technology. This updated edition of the leading guide in the fields. Coupledcavity semiconductor lasers under current modulation.
Improved rate equations for external cavity semiconductor. Depending on the coupling parameters, the system exhibits synchronized hopf bifurcation and the stability switches as the delay varies. Experimental electroluminescence spectrum of a coupled cavity semiconductor laser with a longitudinal mode spacing of fsr0. It is shown that this model is capable of quantifying some c3 laser properties and of fits experimentally measured c3 laser behaviour better than the effective mirror model. They form the backbone of the optical telecommunications infrastructure supporting the internet, and are used in information storage devices, barcode scanners, laser printers and many other everyday products. Pdf we describe a widely tunable coupledcavity semiconductor laser with a nearly continuous tuning capability of approximately 100 nm. N the world of semiconductor lasers, coupled cavity lasers are of interest for two reasons. Coupled mode theory analysis of modesplitting in coupled cavity system qiang li1, tao wang 2, yikai su2, min yan1 and min qiu1. The feasibility of photonic molecules as the basis for a multichannel, wavelengthtunable optical delay device is analysed. This book will appeal to undergraduate and graduate students, scientists and engineers alike. Surface emitting devices based on a semiconductor coupled multilayer cavity for novel terahertz light sources. Majority carriers that are injected to the opposite side. Only the photons that leave the cavity from the mirrors constitute useful output. The study is based on a rateequation model written for.
Most semiconductor lasers are laser diodes, which are pumped with an electrical current in a region where an ndoped and a pdoped semiconductor material meet. They have the ability to trap light in a ring, and recirculate it continuously as long as they remain powered. Pdf we present an analysis of gaalas cleaved coupledcavity c3 lasers. We investigate the operational principle of modelocking in.
The coupledcavity vcsel structure not only exhibits an interesting and rich physics making. We report on achieving tuned single mode operation of a multimode semiconductor laser by coupling it to a veryshort external cavity with selective feedback. Realization of a semiconductorbased cavity soliton laser. The pulse repetition frequency of this 3section device was tunable between 320 and 450 mhz with an external microwave injected signal, the modulation depth of the pulsations was 80100% with a nearly singlelongitudinalmode output spectrum, and the qswitched. Modelocked vertical cavity semiconductor lasers by wenbin jiang inplane semiconductor lasers can be mode locked to generate ultrashort pulses, but the output power is small because of the gain saturation limitation. Q switching cleavedcoupledcavity laser with an integrated. Coupledcavity semiconductor lasers have the potential of offering mode selectivity together with wavelength tunability. Modelocking of monolithic laser diodes incorporating. Pdf widely tunable coupledcavity semiconductor laser. Pdf coupledcavity effects in fm semiconductor lasers. Osa digital wavelength switching by thermal and carrier. Blondel, dynamics of two mutually delayedcoupled semiconductor lasers, optics communications 239, 173180 2004 20.
The dynamic behaviour of coupled pairs of semiconductor lasers is studied using normalmode theory, applied to onedimensional slab and twodimensional circular cylindrical real index confined structures. Small edgeemitting laser diodes generate a few milliwatts or up to 0. External cavity laser diodes ecls are lasers with a very small line width, very good wavelength stability, and very low noise. Synchronized hopf bifurcation analysis in a delaycoupled. We present a detailed theoretical study of a vertical cavity surfaceemitting laser vcsel with two optically coupled, active cavities. Extremely short external cavity esec laser devices vtt. The length of the emitted monomode light pulses is less than 500 ps.
The waveguiding through the coupled microcavities and wavelength switching effect is demonstrated. The results indicate that under certain conditions the direct modulation bandwidth can be doubled with simultaneous phase noise reduction as compared to a conventional laser. If the lasers are of different lengths, then the longitudinal spectra of the two lasers differ, and we expect low thresholds only where. We also need expressions for the light coming out of the laser. We present a detailed theoretical study of a verticalcavity surfaceemitting laser vcsel with two optically coupled, active cavities. A semiconductor laser diode consists of several parts.
The dynamics of a system of two semiconductor lasers, which are delay coupled via a passive relay within the synchronization manifold, are investigated. Keywords external cavity lasers, effective reflectance, semiconductor lasers. We describe fabrication and performance of a qswitching cleavedcoupledcavity laser with an integrated intracavity modulator. Second, a coupledcavity laser makes a good model for a laser system in which there is optical feedback. These devices may not be a simple pn type diode, but behave electrically identical to a pn junction diode. Led or a laser diode r ohms v9v va i v 1ir light emission under forward bias diode made from a direct bandgap semiconductor. Rate equation model of a coupledcavity laser abstract. Here, we report the coupled cavity effects observed in the electroluminescence spectra of monolithic semiconductor diode lasers. Coupling to a second cavity gives an additional degree of freedom that can be used to control the diode laser behavior. In this manuscript, we discuss a design procedure for a recently proposed laser cavity realized with the monolithic integration of two distributed bragg reflector dbr lasers allowing one to extend the modulation bandwidth. Coupling coefficient from the background area of the optical disk. There is a great variety of different semiconductor lasers, spanning wide parameter regions and many different application areas.
Detuned loading in coupled cavity semiconductor lasers. The material of choice for srls is indium phosphide. A laser diode, ld, injection laser diode ild, or diode laser is a semiconductor device similar to a lightemitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diodes junction 3 laser diodes can directly convert electrical energy into light. A grating coupled surface emitting semiconductor laser consists of an inplane laser with an integrated grating coupler that couples the light from the laser out of the waveguide and. Schematic drawing of a laterally coupled cavity semiconductor laser. In order to develop its theory, an im proved form of differential equations which describe the behavior of the external cavity semiconductor laser. Since its invention in 1962, the semiconductor laser has come a long way.
In order to simulate the experimental results displayed in fig. Semiconductor lasers and laser dynamics ix, conference details. Schematic drawing of a laterally coupledcavity semiconductor laser. Two broad categories of coupled cavity diode lasers can be defined. The suppression of secondary modes is described in a rate equation model that is generally useful for a variety of coupled. Abstractwe present an analysis of the steadystate operation of a twoelement coupledcavity.
Without using band gap engineering for the tuning section, 26 and 9channel wavelength switching schemes are achieved via thermal and carrier injection effects. Rateequation model for coupledcavity surfaceemitting. The mode of operation is somewhat di erent than that of the laser described in the previous chapter. The modulation characteristics such as the power response and the chirp dynamic line broadening of singlefrequency coupledcavity semiconductor. For the led it is beneficial to couple as much light out as possible, while in a laser diode it is necessary to build up a high number of photons in order to get stimulated emission. Design and analysis of enhanced modulation response in. Laterally coupledcavity semiconductor lasers 397 fig. A time domain analysis has been performed in order to simulate the experimentally observed results. We show that the induced uniform feedback light from the veryshort external cavity can induce singlemode oscillation over a broad range of optical feedback. For some applications it is desirable to have a semiconductor laser whose wavelength can be tuned over a wide range, at least discretely. The discovery and continued development of the laser has revolutionized both science and industry.
The theoretically calculated spectra are in good agreement with the experimentally observed spectra. Wavelength switching through thermal and carrier injection effects is examined. Vertical cavity surface emitting lasers vcsel, on the other hand, have a. This material comes in the form of ingots that are then further processed into substrates to which layers of other materials are added. Multilongitudinalmode model for cleaved coupled cavity. First, intention ally coupled lasers have been demonstrated to exhibit sin glelongitudinalmode oscillation under smallsignal modulation, fm modulation capabilities, and bistable op eration 11, 2. In order to develop its theory, an im proved form of differential equations which describe the behavior of the external cavity semiconductor laser ecsl is needed. In this paper, we demonstrate the direct modulation of the vcavity laser, which is important for practical applications in lowcost, lowpowerconsumption wdm access networks. Widely tunable multimodeinterference based coupled cavity laser.
Systematic investigation of the influencing parameters of an external cavity laser with a quantum dot gain chip paper 1569 authors. Therefore this type of semiconductor laser supports oscillations of a large number of coupled longitudinal modes. The derivation of the photon rate equations is based on classical electromagnetic theory, while the rate equations for the electrons are written down heuristically in analog with the. Dec 14, 2011 a distinctive discussion of the nonlinear dynamical phenomena of semiconductor lasers. Optical bistability is a rapidly expanding field of current research, and recent progress in this field has stimulated renewed interest in bistable semiconductors lasers 422. Regimes of bandwidth enhancement in coupledcavity semiconductor laser using photonphoton resonance. The advent of miniaturized, semiconductor lasers has made this technology an integral part of. Coupled mode theory analysis of modesplitting in coupled. Externalcavity diode lasers can be made with very compact setups. Alloptical control of bistable solitonic emission states representing small microlasers is.
For example, if the laser output is being cou pled into an optical fiber, any stray reflection back into the laser constitutes a second cavity. We derive a novel rate equation system for a laser consisting of two coupled cavities arranged in tandem. Design of external cavity semiconductor lasers to suppress wavelength shift and mode hopping l. Modelocking of monolithic laser diodes incorporating coupled. In this paper, we demonstrate the direct modulation of the v cavity laser, which is important for practical applications in lowcost, lowpowerconsumption wdm access networks. Consecutive wavelength switching characteristics of a simple, compact, and digitally wavelengthswitchable laser based on vcoupled cavities are reported. Detuned loading in coupled cavity semiconductor laserseffect. The practical and accessible information in this volume will enable the reader to study external cavity diode laser, to build up the systems of external cavity diode laser as well as to develop advanced systems for their particular applications. The above two coupled nonlinear equations can exhibit a wide variety of dynamics associated with the operation of semiconductor lasers. Coupled cavity semiconductor lasers have the potential of offering mode selectivity together with wavelength tunability. I n the world of semiconductor lasers, coupledcavity.
We derive the modulation and noise properties of a semiconductor laser consisting of an active cavity loaded by a passive cavity. Niloy k dutta applications of semiconductor lasers in optical communications and other lightwave technologies have expanded considerably in recent years. Recently, coupled cavity laser diodes have been realized by focused ion beam etching techniques, and passive mode locking of semiconductor diode lasers has been achieved using a coupled cavity geometry. A new semiconductor laser structure with digitally switchable wavelength is proposed. The realization of a cavity soliton laser using a verticalcavity surfaceemitting semiconductor gain structure coupled to an external cavity with a frequencyselective element is reported. Two broad categories of coupledcavity diode lasers can be defined. However, there are also optically pumped semiconductor lasers, where carriers are generated by absorbed pump light, and quantum cascade lasers, where intraband transitions are utilized. Mechanical and optical coupling to an optical fiber. Advances in material purity and epitaxial growth techniques have led to a variety of semiconductor lasers covering a wide wavelength range of 0. Note that there are externalcavity semiconductor lasers which are not diode lasers. Widely tunable coupledcavity semiconductor laser osa. In the last few decades, various solutions have been proposed to increase the modulation bandwidth and, consequently, the transmission bitrate of semiconductor lasers. Semiconductor lasers have important applications in numerous fields, including engineering, biology, chemistry and medicine.
May 01, 2000 recently, coupled cavity laser diodes have been realized by focused ion beam etching techniques, and passive mode locking of semiconductor diode lasers has been achieved using a coupled cavity geometry. The book combines recent results of quantum dot laser modeling with mathematical details and an analytic understanding of nonlinear phenomena in semiconductor lasers and points out possible applications of lasers in cryptography and chaos control. Driven by voltage, the doped pntransition allows for recombination of an electron with a hole. Blondel, dynamics of two mutually delayedcoupled semiconductor lasers, optics communications 239, 173180 2004. Consecutive wavelength switching characteristics of a simple, compact, and digitally wavelengthswitchable laser based on v coupled cavities are reported. Inducing tunable singlemode operation of fabryperot. Narrowbanded ecl lasers are characterized by a very small line width, low noise, and very good wavelength stability.
In theory, both the wavelength and output power of the device are dependent on the strength of. Monolithic coupledcavity laser diodes for biosensing. Direct modulation of widely tunable vcavitylaser for low. It is shown that regions of stable behaviour depend not only on pumping rate and laser separation, but also on the degree of guidance in the structures.
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