Optoelectronic device simulation of Bragg reflectors and their influence on surface-emitting laser characteristics

Winston, D.W.; Hayes, R.E.

doi:10.1109/3.663456

Cited by 45 publications

(23 citation statements)

References 19 publications

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“…7 corresponds to only a few millielectronvolts in terms of energy. The most likely cause is the reduction of the QW bandgap at elevated temperature according to (11), as briefly discussed in [51].…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…Based on the updated lattice temperature profile, a recomputation is conducted for temperature-dependent material parameters including the bandgap, carrier mobilities, and refractive indices. We use Varshni formula for the temperature dependence of the energy bandgap (11) where and are temperature coefficients. The temperature dependence of the carrier mobilities is assumed to obey a simple power law as (12) where the coefficients are determined from fittings with experiments.…”

Section: Self-consistent Coupling Of Modelsmentioning

confidence: 99%

“…Yu et al developed a numerically appealing rate equation approach with an oversimplified carrier transport treatment and an empirical temperature dependence of the threshold current density [9], [10]. The comprehensive hydrodynamic model by Winston and Hayes [11] treats the DBR structures in detail, but only in one dimension. Device-level simulations have been performed to investigate the self-heating effects for both VCSELs and long wavelength edge emitting lasers by Piprek et al [12]- [14].…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of self-heating effects of oxide-confined vertical-cavity surface-emitting lasers

Liu

Choquette

et al. 2005

IEEE J. Quantum Electron.

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Section: Simulation Results and Discussionmentioning

confidence: 99%

Section: Self-consistent Coupling Of Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of self-heating effects of oxide-confined vertical-cavity surface-emitting lasers

Liu

Choquette

et al. 2005

IEEE J. Quantum Electron.

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“…Hence, a sophisticated design is necessary to facilitate electrical pumping, especially through p-doped DBRs where the low hole mobilities otherwise yield a prohibitively high device resistance. Several solutions like heavy doping, various types of mole fraction grading, and δ-doping of the interfaces have been developed to circumvent this problem in VCSELs [17,23,24]. Since the electron and hole mobilities as well as the conduction-band and valenceband offsets in an AlGaAs-based DBR differ significantly, different measures have to be taken for n-and p-DBRs in order to achieve acceptable device resistances.…”

Section: N-vs P-doped Dbr and Contact Geometrymentioning

confidence: 99%

On the design of electrically pumped vertical-external-cavity surface-emitting lasers

et al. 2008

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Vertical-external-cavity surface-emitting lasers (VECSELs) yield an excellent beam quality in conjunction with a scalable output power. This paper presents a detailed numerical analysis of electrically pumped VECSEL (EP-VECSEL) structures. Electrical pumping is a key element for compact laser devices. We consider the optical loss, current confinement, and device resistance. The main focus of our investigation is on the achievement of an adequate radial carrier distribution for fundamental transverse mode operation. It will be shown that a trade off between the conflicting optical and electrical optimization has to be found and we derive an optimized design resulting in guidelines for the design of EP-VECSELs which are compatible with passive mode locking. Vertical-external-cavity surface-emitting lasers (VECSELs) [1] are of high scientific and industrial interest due to their large fundamental transverse mode output power, scaling with the device radius, the near diffraction limited output beam, and the suitability for intracavity frequency conversion [2] and passive mode locking [3,4]. Passive mode locking of an optically pumped VECSEL has been demonstrated with a semiconductor saturable absorber mirror (SESAM) [5] in a folded external cavity. After the first passively mode locked VECSEL was demonstrated in the year 2000 [6], the milestone of nearly 1 W average output power was achieved in 2002 with improved thermal management [7]. The pulses in the early experiments were often strongly chirped, but mode-locking dynamics in VECSELs revealed that a soliton-like pulse-shaping mechanism in the positive-dispersion regime can help to generate short pulses with low chirp. With the aid of intracavity dispersion control, it then became possible to obtain nearly transform limited picosecond pulses with record high output powers of 2.1 W at 4 GHz [4] and 1.4 W at 10 GHz [8]. The pulse width could be u Fax: +41-44-633-10-59, E-mail: keller@phys.ethz.ch significantly shortened to the sub-500-fs regime using faster SESAMs based on the ac Stark effect [9]. The vertical integration of the absorber into one monolithic structure with the gain quantum wells (QWs) is an important step towards higher pulse repetition rates with decreased cavity size and wafer-scale integration. This has been achieved for the first time and is referred to as the mode-locked integrated-externalcavity surface-emitting laser (MIXSEL) [10]. So far, all these devices have been optically pumped, which involves a more complex optical setup. Thus, an important step towards waferscale fabrication of compact ultrafast VECSELs is the design of electrically pumped VECSEL (EP-VECSEL) structures. This is challenging because of optical losses and Joule heating in the doped layers. Nevertheless, continuous-wave (cw) EP-VECSELs have been demonstrated [11,12] and output powers of up to 900 mW have been obtained with a 150-µm device diameter in multimode operation [13]. Also, mode locking with down to 15-ps FWHM pulse width [14] and a wafer-scale EP-VECSEL w...

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“…Nakwaski and Osinski have also evaluated and compared various temperature models for VCSEL simulators preceeding 1997 [2]. Recently, Winston and Hayes have used the energy-balance model [7] with a simplified transport model to simulate VCSELs in one dimension. However, these temperature models do not treat the Peltier heat explicitly and it is not immediately clear how carrier transport affects the lattice temperature model.…”

Section: Introductionmentioning

confidence: 98%

Lattice Temperature Model and Temperature Effects in Oxide-Confined VCSEL’s

Liu

Hess

2004

J Comput Electron

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A lattice temperature model is derived for oxide-confined vertical cavity surface emitting lasers (VCSELs) based on carrier transport and the conservation of energy. Peltier heat is caused by the bandedge and quasi-Fermi level discontinuities at a heterojunction. However, considering the device size, Peltier heat needs to be distributed and is not just generated at the interface, otherwise, an anomolous spike in temperature will occur. We have developed a novel treatment to model the Peltier heat at a heterojunction by use of a Monte Carlo simulation. Peltier heat is found to be a major heat contributor, and it results in a rapid and high temperature rise in the separate confinement heterostructure (SCH) region of the laser diode. We have also shown that the carrier thermal conductivities for materials with high mobilities must be included at high carrier densities because they contribute to additional spreading of the thermal energy. Subsequently, this lattice temperature model is coupled self-consistently to electronic and optical solvers to form a complete simulator for VCSELs. Self-heating causes a fast temperature rise when the VCSEL is operated under continuous wave conditions, causing resonant wavelength changes and an eventual thermal rollover. The resonant wavelength shift has been shown to be caused mainly by the heating of the distributed Bragg reflectors even though the peak temperature occurs within the SCH region. Possible physical factors causing the thermal rollover have also been examined with our complete simulator. The Auger recombination process is found to be one of the main factors causing the thermal rollover in 980 nm oxide-confined VCSELs while the photon lifetime is a factor in determining the position of the thermal rollover. We have also achieved a very good match between our simulated results and experimental data.

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Optoelectronic device simulation of Bragg reflectors and their influence on surface-emitting laser characteristics

Cited by 45 publications

References 19 publications

Numerical investigation of self-heating effects of oxide-confined vertical-cavity surface-emitting lasers

Numerical investigation of self-heating effects of oxide-confined vertical-cavity surface-emitting lasers

On the design of electrically pumped vertical-external-cavity surface-emitting lasers

Lattice Temperature Model and Temperature Effects in Oxide-Confined VCSEL’s

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