Whispering-Gallery-Mode (WGM) photonic crystal microcavity is a kind of photonic crystal application and can
potentially be used for miniaturized photonic devices, such as thresholdless lasers. In this paper we study the WGM of
photonic crystal microcavities focusing on the so called H2 cavities which are formed by removing seven air holes. The
WGM in these large-size cavities has some advantages compared with single defect WGM in the view of real device
applications. We further add a central air hole in the cavity region to analyze the effect on WGM in the microcavity by
finite difference time domain (FDTD) and plane wave expansion (PWE). It is found that the tolerance of WGM is large
enough for the fabrication of electrical injection structure.
A novel 980nm bottom-emitting VCSELs array with high power density and good beam property of Gaussian far-field
distribution is reported. This array is composed of 5 symmetrically-arranged elements of 200&μm,150μm and
100μm-diameterμwith the center spacings of 300μm and 250μm respectively. The maximum power is 880mW at a
current of 4A, corresponding to 1KW/cm<sup>2</sup> average optical power density. The differential resistance is Ω with a
threshold of 0.56A. The novel array is compared with a 300μm-aperture-size single device and a 4*4 2-D array with
50μm element aperture size and 250μm centre spacing. The three devices have the same lasing area. The conclusion is
that the novel array is better in the property of output power, threshold current, lasing spectra, far-field distribution etc.
Pulsed anodic oxidation technique, a new way of forming current blocking layers, was successfully used in
ridge-waveguide QW laser fabrication. We apply this method in 980nm VCSELs fabrication to form a high-quality
native oxide current blocking layer, which simplify the device process. A significant reduction of threshold current and a
distinguished device performance are achieved. The 500μm-diameter device has a current threshold as low as 0.48W.
The maximum CW operation output power at room temperature is 1.48W. The lateral divergence angle <i>θ</i><i><sub>parallel</sub></i>and vertical divergence angle <i>θ</i><sub>perpendicular</sub> are as low as 15.3° and 13.8° without side-lobes at a current of 6A.
By using bottom-emitting structure, we will develop laser diode (LD) pumped 980 nm VECSEL with active region of InGaAs/GaAsP/AlGaAs system. Because the thickness of barrier layer and absorption layer exceed that of quantum well, single well approximation model (KP method) can be used to calculate the band structure of VECSEL. The Schrodinger equation of finite deep potential well can be adopted to calculate the energy level structures of electron, heavy and light holes. According to the transition selection rule, we theoretically obtained the emitting wavelength of VECSEL and calculated quasi-Femi energy of valence band and conduction band based on the analysis of energy level structure of electron and holes. By analyzing the gain of strained quantum wells, we calculated the gain of VECSEL using transition matrix elements of electron, heavy and light holes. We give out the threshold gain, output power and other characteristic parameters. We will study the configuration of VECSEL and pumping scheme. We designed external cavity mirror, active region and bottom-emitting structure. A LD-pumped vertical external cavity surface-emitting laser whose output power is greater than 1.0 W can be predicted.
The high power bottom-emitting vertical-cavity surface-emitting lasers (VCSELs) and laser arrays emitting at 980 nm are reported. Extensive investigations on size scaling behavior of thermal properties of single devices show limits of attainable output characteristics. The maximum continuous wave (CW) output power at room temperature of single devices with aperture size up to 500 μm is as high as 1.95 W. The key characteristics such as maximum output power, wavelength and thermal resistance are discussed. The bottom-emitting arrays of 16 elements and 200 μm aperture size of individual elements show output power of CW 1.35 W at room temperature. The far-field angle is below 17° for all driving current, which is very favorable for focusing or collimating optics.
We describe design, numerical simulation and characteristics of high-power optical pumped VECSELs at different wavelength (980nm, and 1300nm). The device design realizes the integrating diode-pumped lasers with vertical-cavity surface-emitting laser structure, drawing on the advantages of both. With periodical gain element structure, optical pumped VECSEL is scalable to watt level output. The characteristics such as threshold condition and output power are calculated theoretically. An optimum number of quantum wells and external mirror reflectivity are obtained from the calculation results, and the thermal characteristic is also considered. Finally the calculation results also predict high output power in this kind of device structure.
We report on bottom-emitting vertical-cavity surface-emitting lasers (VCSEL's) and laser arrays providing high output powers in the 980-nm wavelength regime. Single devices with active diameters of 500 μm show high output powers of 1.95 W at room temperature. Its threshold current is 510 mA, and the maximum spatially averaged optical power density is 0.93 kW/cm<sup>2</sup>. A 16 elements array with 200μm aperture size (250μm center spacing) of individual elements shows a CW output power of 1.21W at room temperature, resulting in a average optical power density of 1KW/cm<sup>2</sup>. The threshold current of the array is 1.32A and the lasing peak wavelength is 981.9 nm. The distinction of emission spectrums between the single device and the array is discussed.
We describe the design, fabrication, and calculation characteristics of the 980nm high-power diode-pumped vertical external-cavity
surface-emitting laser(VECSEL).From our calculation, the VECSEL with active region of InGaAs/GaAsP/AlGaAs system can operate near 1w in a single transverse mode.