| 1. |
- Amann, M. C., et al.
(author)
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Focus on advanced semiconductor heterostructures for optoelectronics
- 2009
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In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 11, s. 125012 artno-
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Journal article (peer-reviewed)abstract
- Semiconductor heterostructures are the basic materials underlying optoelectronic devices, particularly lasers and light-emitting diodes (LEDs). Made from various III-V-, II-VI-, SiGe- and other compound semiconductors, modern semiconductor devices are available for the generation, detection and modulation of light covering the entire ultra-violet to far-infrared spectral region. Recent approaches that introduced multilayer heterostructures tailored on the lower nanometre scale made possible artificial semiconductors with new properties, such as extended wavelength coverage, that enabled new applications. Together with ongoing progress on wide-gap semiconductors, the optical wavelengths accessible by semiconductor devices are steadily expanding towards the short-wavelength ultra-violet regime, as well as further into the far-infrared and terahertz spectral regions. It is the aim of this focus issue to present cutting-edge research topics on the most recent optoelectronic material and device developments in this field using advanced semiconductor heterostructures.
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| 2. |
- Arafin, S., et al.
(author)
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Comprehensive analysis of electrically-pumped GaSb-based VCSELs
- 2011
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In: Optics Express. - 1094-4087 .- 1094-4087. ; 19:18, s. 17267-17282
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Journal article (peer-reviewed)abstract
- This paper discusses several performance-related aspects of electrically-pumped GaSb-based buried tunnel junction VCSELs with an emission wavelength of 2.6 mu m based on theoretical and experimental results. These results allow a deeper insight into the internal device physics, such as radial diffusion of carriers, maximum continuous-wave operating temperature, diffraction loss, internal temperature, gain and loss parameters, internal quantum efficiency of the active region etc. These parameters can be taken into account while designing mid-infrared lasers which leads to an improved device performance. A simple thermal model of the devices based on the two-dimensional (2-D) finite element method using the material data from the literature is also presented. In addition, an application-based result utilizing these lasers for the measurement of absolute water vapor concentration by wavelength modulation spectroscopy (WMS) method are also described, hinting that devices are well-suited for the targeted sensing applications.
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| 3. |
- Arafin, S., et al.
(author)
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Large-Area Single-Mode GaSb-based VCSELs using an Inverted Surface Relief
- 2010
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In: 23rd Annual Meeting of the IEEE Photonics Society, PHOTINICS 2010. - 9781424453689 ; , s. 61-62
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Conference paper (peer-reviewed)abstract
- Large-area GaSb-based BTJ VCSELs at ∼2.35 μm were fabricated using an inverted surface relief technique to support the single transverse mode operation. The devices operate in continuous-wave and are (electro-)thermally tunable over 6 nm.
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| 4. |
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| 5. |
- Davani, Hooman A., et al.
(author)
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Polarization investigation of a tunable high-speed short-wavelength bulk-micromachined MEMS-VCSEL
- 2012
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819489197 ; 8276, s. Art. no. 82760T-
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Conference paper (peer-reviewed)abstract
- We report the investigation of the state of polarization (SOP) of a tunable vertical-cavity surface-emitting laser (VCSEL) operating near 850 nm with a mode-hop free single-mode tuning range of about 12 nm and an amplitude modulation bandwidth of about 5 GHz. In addition, the effect of a sub-wavelength grating on the device and its influence on the polarization stability and polarization switching has been investigated. The VCSEL with an integrated sub-wavelength grating shows a stable SOP with a polarization mode suppression ratio (PMSR) more than 35 dB during the tuning.
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| 6. |
- Davani, Hooman A., et al.
(author)
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Widely Electro Thermal Tunable Bulk-Micromachined MEMS-VCSEL Operating Around 850nm
- 2011
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In: Conference on Lasers and Electro-Optics/Pacific Rim, CLEOPR 2011; Sydney; Australia; 28 August 2011 through 1 September 2011. - 2162-2701. - 9780977565771 ; , s. 32-34
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Conference paper (peer-reviewed)abstract
- We present the highest reported continues tuning range of 37 nm and fastest electro thermal tuning speed of 700 Hz achieved with tunable vertical-cavity surface-emitting lasers (VCSEL) and semiconductor DBRs at 850 nm wavelength range.
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| 7. |
- Davani, Hooman A., et al.
(author)
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Widely tunable high-speed bulk-micromachined short-wavelength MEMS-VCSEL
- 2010
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In: Semiconductor Laser Conference (ISLC), 2010 22nd IEEE International. - 0899-9406. - 9781424456833 ; , s. 9-10
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Conference paper (peer-reviewed)abstract
- We present the first results of a high-speed bulk-micromachined tunable vertical-cavity surface-emitting laser (VCSEL) operating near 850nm using a half-symmetric resonator with a movable curved microelectromechanical system (MEMS) membrane.
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| 8. |
- Gierl, Christian, et al.
(author)
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Tuneable VCSEL aiming for the application in interconnects and short haul systems
- 2011
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819484963 ; 7959
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Conference paper (other academic/artistic)abstract
- Widely tunable vertical cavity surface emitting lasers (VCSEL) are of high interest for optical communications, gas spectroscopy and fiber-Bragg-grating measurements. In this paper we present tunable VCSEL operating at wavelength around 850 nm and 1550 nm with tuning ranges up to 20 nm and 76 nm respectively. The first versions of VCSEL operating at 1550 nm with 76 nm tuning range and an output power of 1.3mW were not designed for high speed modulation, but for applications where only stable continious tuning is essential (e.g. gas sensing). The next step was the design of non tunable VCSEL showing high speed modulation frequencies of 10 GHz with side mode supression ratios beyond 50 dB. The latest version of these devices show record output powers of 6.7mW at 20 °C and 3mW at 80 °C. The emphasis of our present and future work lies on the combination of both technologies. The tunable VCSEL operating in the 850 nm-region reaches a modulation bandwidth of 5.5GHz with an output power of 0.8mW.
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| 9. |
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