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- Adolfsson, Göran, 1981, et al.
(author)
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Direct observation of lateral carrier diffusion in ridge waveguide InGaNAs lasers
- 2009
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In: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 21:134, s. 134-136
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Journal article (peer-reviewed)abstract
- We present results from measurements of the subthreshold lateral spontaneous emission profile in 1.3-mu m wavelength ridge waveguide InGaNAs quantum-well lasers using a scanning near-field optical microscopy technique. The measurements reveal the presence of significant lateral carrier diffusion which has a profound effect on the temperature dependence of the threshold current. This effect is frequently omitted when the characteristic temperature of the threshold current is considered.
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| 3. |
- Adolfsson, Göran, 1981, et al.
(author)
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Effects of Lateral Diffusion on the Temperature Sensitivity of the Threshold Current for 1.3 um Double Quantum-Well GaInNAs/GaAs Lasers
- 2008
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In: IEEE Journal of Quantum Electronics. ; 44:7, s. 607-616
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Journal article (peer-reviewed)abstract
- We present an experimental and theoretical investigationof the temperature dependence of the threshold current fordouble quantum well GaInNAs–GaAs lasers in the temperaturerange 10 C–110 C. Pulsed measurements of the threshold current have been performed on broad and narrow ridge wave guide(RWG) lasers. The narrow RWG lasers exhibit high characteristic temperatures (T0)of 200 K up to a critical temperature (Tc), above which T0 is reduced by approximately a factor of 2. The T0-values for broad RWG lasers are significantly lower than those for the narrow RWG lasers, with characteristic temperatures on the order of 100 (60) K below (above). Numerical simulations, using a model that accounts for lateral diffusion effects, show good agreement with experimental data and reveal that a weakly temperature dependent lateral diffusion current dominates thethreshold current for narrow RWG lasers.
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| 7. |
- Adolfsson, Göran, 1981, et al.
(author)
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Realization of spectrally engineered semiconductor Fabry-Perot lasers with narrow geometrical tolerances
- 2011
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In: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 109:9, s. 093112-
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Journal article (peer-reviewed)abstract
- Spectrally engineered semiconductor Fabry-Perot laser resonators are designed to enhance the optical feedback for selected longitudinal modes, which thereby require less gain for lasing. This is achieved by introducing refractive index perturbations along the length of the resonator. However,the physical realization of these resonators is a challenge because of very narrow tolerances; in particular the need for precise positioning of the end facets of the resonator in relation to the perturbations, and the excess propagation loss associated with the perturbations, has been a majorconcern. We report on a method to achieve high-quality end facet mirrors enabling precise positioning relative to the perturbations, the latter which are realized as lateral corrugations of the waveguide. Measurements show that the mirror quality is comparable to that of cleaved mirrorsand that the additional loss introduced by the perturbations adds
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| 8. |
- Adolfsson, Göran, 1981, et al.
(author)
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Spectral engineering of semiconductor Fabry–Perot laser cavities in the weakly and strongly perturbed regimes
- 2010
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In: Journal of the Optical Society of America B: Optical Physics. - 1520-8540 .- 0740-3224. ; 27:1, s. 118-127
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Journal article (peer-reviewed)abstract
- By inserting index perturbations at certain positions along a semiconductor Fabry–Perot laser cavity thethreshold gain for one or several of the longitudinal cavity modes can be selectively lowered to facilitate, e.g.,single-mode or two-color operation. Previous design methods were limited to a fairly small number of perturbations,leading to only weakly perturbed cavities and thus a limited freedom in tailoring the spectral propertiesof the laser. In our approach we fully account for all multiple-reflection events and use a search spacethat permits any distribution of the locations and lengths of the perturbations. We are therefore able to designcavities with almost arbitrary spectral properties with very low threshold gain values for, e.g., the lasingmodes of a two-color cavity. Constraining the design by reducing the geometrical freedom, which can be used toincrease the smallest feature size to simplify fabrication, we seamlessly approach the weakly perturbed regimewhile maintaining much of the freedom for spectral engineering.
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| 9. |
- Dumitrescu, Mihail, et al.
(author)
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10 Gb/s uncooled dilute nitride optical transmitters operating at 1300 nm
- 2009
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In: 2009 Conference on Optical Fiber Communication, OFC 2009; San Diego, CA; United States; 22 March 2009 through 26 March 2009. - Washington, D.C. : OSA. - 9781557528650
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Conference paper (peer-reviewed)abstract
- Dilute-nitride lasers with record performances have been used to build uncooled transceivers and failure free 10 Gb/s optical transmission was achieved over 815 m of multimode Corning InfiniCor fiber under the LRM standard.
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| 10. |
- Lim, J.J., et al.
(author)
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Static and dynamic performance optimization of a 1.3 µm GaInNAs ridge waveguide laser
- 2008
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In: 2008 International Conference on Numerical Simulation of Optoelectronic Devices, NUSOD'08; Nottingham; United Kingdom; 1 September 2008 through 4 September 2008. - 9781424423071 ; , s. 121-122
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Conference paper (peer-reviewed)abstract
- In this work, we optimise the structure of an uncooled directly modulated 1.3 μm GaInNAs ridge waveguide laser for high temperature operation. The static and dynamic performance of the optimised design is analyzed using an accurate in-house 2D electro-opto-thermal laser simulator. The optimised structure Is shown to have a lower threshold current, higher efficiency, higher modulation bandwidth and lower vertical beam divergence compared to a reference structure with a conventional design. Large-signal 10 Gbit/s digital modulation simulations were performed and demonstrate the improved performance of the optimised structure especially under high temperature operation.
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