Low-temperature operation of vertical cavity surface-emitting lasers (original) (raw)
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Room-temperature operation of transistor vertical-cavity surface-emitting laser
Electronics Letters, 2013
We demonstrate the first room-temperature operation of a transistor vertical-cavity surface-emitting laser (T-VCSEL). Fabricated using an epitaxial regrowth process, the T-VCSEL is electrically a Pnp-type bipolar junction transistor and consists of an undoped AlGaAs/GaAs bottom DBR, an InGaAs triple-quantum-well (TQW) active layer, an Si/SiO2 dielectric top DBR, and an intracavity contacting scheme with three electrical terminals. The output power is controlled by the base current in combination with the emitter-collector voltage, showing a voltage-controlled operation mode. A low threshold base-current of 0.8 mA and an output power of 1.8 mW have been obtained at room temperature. Continuous-wave operation was performed up to 50°C .
Enhanced performance of offset-gain high-barrier vertical-cavity surface-emitting lasers
IEEE Journal of Quantum Electronics, 1993
The temperature dependence and power output of vertical-cavity surface-emitting lasers (VCSEL's) are of great importance when considering these devices for real applications. We have deliberately offset the peak wavelength of the quantum well from the wavelength of the device cavity mode so that they are aligned at elevated temperatures. The result of this design change is to produce an 8 pm diameter VCSEL capable of operation to 145"C, as well as CW operation of broad area (70 pm diameter) heat-sunk devices to record power levels. Fiber coupling experiments were also carried out, and a record 33 mW CW power was coupled to a multimode fiber.
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.
IEE Proceedings - Optoelectronics, 2005
The wafer of a 760 nm vertical-cavity surface-emitting laser (VCSEL), designed for oxygen sensing up to high temperatures, is investigated using photomodulated reflectance (PR). By varying the angle of incidence, the VCSEL cavity mode (CM) wavelength is tuned through the positions of two excitonic quantum well (QW) transitions. The PR is also measured over a large temperature range to determine when the QW ground-state transition is tuned with the CM. When tuned, the QW/CM PR lineshape becomes anti-symmetric, as predicted by theory. This occurs at 388 K, where the CM and QW wavelengths coincide at 760.7 nm. It is also observed that when tuned, the CM width measured in the reflectance spectrum is maximised. Temperature dependent device studies are also conducted on a 760 nm edge-emitting laser containing a similar active region as the VCSEL. It is found that up to 250 K the device behaves ideally, with the threshold current being entirely due to radiative recombination. However, as the temperature increases, electron leakage into the indirect X-minima of the barrier and cladding layers becomes increasingly significant. At 300 K, approximately 25% of the threshold current is found to be attributed to electron leakage and this increases to 85% at 388 K. The activation energy for this leakage process is determined to be 255^5 meV, indicating that electron escape from the QWs into the X-minima of the barrier and/or cladding layers is chiefly responsible for the device's poor thermal stability. These results suggest that VCSELs containing this active region are likely to suffer significantly from carrier leakage effects.
Thermal effects in 2.x μm vertical-external-cavity-surface-emitting lasers
Journal of Applied Physics, 2012
The thermal behavior of vertical-external-cavity-surface-emitting lasers (VECSELs) is investigated. The temperature distribution in operating VECSELs has been experimentally determined for various operating conditions and different cooling schemes. The implementation of the thermoreflectance technique for the thermal analysis of VECSELs is demonstrated. This technique allows for high resolution mapping of a temperature increase resulting from the optical pumping of the VECSEL. The influence of a heatspreader on the VECSEL temperature is investigated. It is demonstrated that the use of an intracavity heatspreader bonded to the VECSEL chip causes a pronounced decrease of the temperature of the device. From the heat balance in the device, the lowering of the temperature of the VECSEL during operation is predicted. This is experimentally confirmed. V
IEEE Journal of Selected Topics in Quantum Electronics, 2003
We have investigated the temperature and pressure dependence of the threshold current ( th ) of 1.3 m emitting GaInNAs vertical-cavity surface-emitting lasers (VCSELs) and the equivalent edge-emitting laser (EEL) devices employing the same active region. Our measurements show that the VCSEL devices have the peak of the gain spectrum on the high-energy side of the cavity mode energy and hence operate over a wide temperature range. They show particularly promising th temperature insensitivity in the 250-350 K range. We have then used a theoretical model based on a 10-band k.P Hamiltonian and experimentally determined recombination coefficients from EELs to calculate the pressure and temperature dependency of th . The results show good agreement between the model and the experimental data, supporting both the validity of the model and the recombination rate parameters. We also show that for both device types, the super-exponential temperature dependency of th at 350 K and above is due largely to Auger recombination.
IEEE Photonics Technology Letters, 2000
Abstruct-We demonstrate for the first time the CW performance of AlGaAs-GaAs vertical-cavity surface-emitting lasers (VCSEL's) at cryogenic temperatures from 6 K to 200 K. By detuning the cavity mode with respect to the gain peak so that optimum dc lasing operation is achieved at -100 K, we find that this optimum lasing performance can be maintained down to temperatures as low as 6 K. Across a broad range of temperatures from 200 K to 6 K, the minimum threshold current of a 16-pm diameter VCSEL stayed below 4 mA, while its -3-dB modulation bandwidth increased by about 70% to 11 GHZ at 6 K, and the external slope efficiency is greater than 70%.
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.
Thermally induced local gain suppression in vertical-cavity surface-emitting lasers
Applied Physics Letters, 2000
Joule heating is one of the dominant mechanisms determining the transverse mode formation in vertical-cavity surface-emitting lasers at high injection currents. We give experimental evidence that in this operation regime, strong heating results in local gain suppression in the center of the laser, which overbalances the confining effect of thermal lensing, and thus favors the formation of high order modes. From our investigations of small aperture devices, we conclude that efficient heat removal is crucial for achieving single mode emission at high injection currents. © 2000 American Institute of Physics. ͓S0003-6951͑00͒03123-5͔
Ieee Photonic Technol Lett, 1996
We demonstrate for the first time the CW performance of AlGaAs-GaAs vertical-cavity surface-emitting lasers (VCSEL's) at cryogenic temperatures from 6 K to 200 K. By detuning the cavity mode with respect to the gain peak so that optimum dc lasing operation is achieved at-100 K, we find that this optimum lasing performance can be maintained down to temperatures as low as 6 K. Across a broad range of temperatures from 200 K to 6 K, the minimum threshold current of a 16-pm diameter VCSEL stayed below 4 mA, while its-3-dB modulation bandwidth increased by about 70% to 11 GHZ at 6 K, and the external slope efficiency is greater than 70%.