Thermal effects in 2.x μm vertical-external-cavity-surface-emitting lasers (original) (raw)
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Heat Management in High-Power Vertical-External-Cavity Surface-Emitting Lasers
IEEE Journal of Selected Topics in Quantum Electronics, 2000
The thermal properties of a high-power verticalexternal-cavity surface-emitting laser (VECSEL) are studied experimentally, focusing on the generation, distribution, and removal of excess heat under extreme pumping conditions. Different heatspreading and heat-transfer approaches are analyzed. The performance of the device is optimized yielding a maximum emitted power beyond 70 W from a single spot. Finally, the potential for power-scaling in VECSELs and its restrictions are examined.
IEEE Journal of Quantum Electronics, 2019
III-N VCSELs undergo severe self-heating which limits the output optical power. This makes thermal management a critical design consideration. The three most common VCSEL structures (hybrid VCSELs, flip-chip VCSELs and ELOG VCSELs) have been studied using advanced self-consistent electro-opto-thermal numerical simulations. The key geometric and material parameters affecting the thermal resistance of these devices have been identified. Our simulations suggest that some of the proposed solutions and design modifications can increase the maximum optical output power by as much 100%. This manuscript also describes the correct method of using numerical simulation in device design-to predict trends and isolate the key factors affecting device performance.
Temperature characteristics of InGaAs/GaAs vertical cavity surface emitting laser
Optoelectronics Letters, 2005
The temperature characteristics for the different lasing modes at 300 K of intracavity contacted In-GaAs/GaAs Vertical Cavity Surface Emitting Lasers(VCSELs) have been investigated experimentally by using the SV-32 cryostat and LD200205 test system. In combination with the simulation results of the reflective spectrum and the gain peak at different temperatures, the meas0rement results have been analyzed. In addition, the dependence of device size on temperature characteristics is discussed. The experimental data can be used to optimally design of VCSEL at high or cryogenic temperature.
Low-temperature operation of vertical cavity surface-emitting lasers
IEEE Photonics Technology Letters, 1995
Vertical Cavity Surface-Emitting Lasers originally designed for room temperature operation are operated at 77 K. At this temperature, the gain peak and the cavity mode do not overlap. However, due to joule heating, at high biasing levels they come back into alignment and high single-mode output powers and large modulation bandwidths are observed.
Thermal Equivalent Circuit Model for Coupled-Cavity Surface-Emitting Lasers
IEEE Journal of Quantum Electronics, 2015
In this paper, for the first time, an equivalent circuit model, including temperature effects, is introduced for coupledcavity vertical cavity surface-emitting lasers (CC-VCSELs). This model is based on a set of coupled rate equations for two carrier concentrations, a single longitudinal optical mode, and the temperatures of the cavities. By considering the main intrinsic physical processes inside the active layer, we modified the standard coupled rate equations to account for the effects of both the thermal-dependent laser gain and active layer carrier leakage current on CC-VCSELs performance. The presented model can be used in general purpose circuit simulators to study the influence of the thermal dependence of the laser gain spectrum, cavity resonance modes, and carriers leakage currents on the light-current (L-I) characteristics under different biasing conditions with a reasonable accuracy. Simulations results show that the threshold characteristic and linearity of the L-I curve are severely related to the temperature. On the other hand, the temperature variations cause the output optical power rollover. In addition, we verify that the variations of the threshold current with temperature have a parabolic form. Our results are in good agreement with the reported experimental data.
Thermal cross-talk evaluation of densely integrated vertical cavity surface emitting laser array
IEICE Electronics Express, 2004
We carried out the evaluation of the thermal cross-talk in a 1.2 µm band densely packed vertical cavity surface emitting laser (VCSEL) array for the first time. The spacing of neighboring elements is as small as 20 µm. We measured the wavelength shift for different integrated elements, which gives us the temperature change, as a function of the distance from a heat source. We also carried out three-dimensional thermal modeling for the array, which shows good agreement with the experiment. It is predicted that the lasing wavelength of the array is affected by a thermal cross-talk when adjacent elements are operated at the same time.
Spatially resolved thermal characterization of packaged vertical cavity surface-emitting lasers
… , IEEE Transactions on, 1999
This work deals with the experimental thermal characterization of several types of commercially available laser diodes, both surface and edge emitting, with their own package. The analysis was performed using the TRAIT technique, which makes use of thermal transient measurements and which yields the knowledge of the thermal resistance as a sum of several contributions due to the various parts of the chip-package system. The high resolution with which the transient were recorded, allowed to identify the small thermal resistance contributions of the attaching interfaces and discuss their dependence on the deposition technology.
Applied Physics Letters, 2010
The performance of a 1040 nm vertical-external-cavity surface-emitting laser is studied as function of the size and shape of the pumped area. The input-output characteristics of the device are monitored while simultaneously tracking the temperature in the active region. It is shown that the pump spot shape plays a crucial role in optimizing the laser output. Improvements up to a factor of 5 are found for a super-Gaussian in comparison to the standard Gaussian shape. For the large pump-spot sizes needed for high output powers, it turns out that the power-scalability breaks down due to the suppressed lateral heat flow.
IEEE Journal of Quantum Electronics, 1993
Two-dimensional physical models for single-mode index guided vertical-cavity surface-emitting lasers (VCSEL's) are developed and compared with experimental measurements on state-of-the-art devices. Starting with the steady-state electron and photon rate equations, the model calculates the above threshold light-current (LI) characteristics. Included are temperature effects, spatial hole burning effects, carrier diffusion, surface recombination, and an estimation of optical losses. The model shows that the saturation of output power in the experimental devices is due to carrier leakage over the heterojunction and not simply the shifting of the gain peak relative to the cavity mode. Using the verified model new designs are analyzed, showing that output powers greater than 15 mW and power efficiencies above 20% should be achievable with existing processing technology.