| 1. |
|
|
| 2. |
- Adolfsson, Göran, 1981-, et al.
(författare)
-
Direct observation of lateral carrier diffusion in ridge waveguide InGaNAs lasers
- 2009
-
Ingår i: IEEE Photonics Technology Letters. - 1041-1135. ; 21:134, s. 134-136
-
Tidskriftsartikel (refereegranskat)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.
|
|
| 3. |
- Adolfsson, Göran, 1981-, et al.
(författare)
-
Effects of Lateral Diffusion on the Temperature Sensitivity of the Threshold Current for 1.3 um Double Quantum-Well GaInNAs/GaAs Lasers
- 2008
-
Ingår i: IEEE Journal of Quantum Electronics. ; 44:7, s. 607-616
-
Tidskriftsartikel (refereegranskat)abstract
- We present an experimental and theoretical investigation of the temperature dependence of the threshold current for double quantum well GaInNAs–GaAs lasers in the temperature range 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 the threshold current for narrow RWG lasers.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Adolfsson, Göran, 1981-, et al.
(författare)
-
Realization of spectrally engineered semiconductor Fabry-Perot lasers with narrow geometrical tolerances
- 2011
-
Ingår i: AIP Journal of Applied Physics. - 0021-8979. ; 109:9
-
Tidskriftsartikel (refereegranskat)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 major concern. 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 mirrors and that the additional loss introduced by the perturbations adds < 10 cm-1 to the overall propagation loss, provided that the perturbations are densely enough spaced along the resonator. This implies that the number of perturbations should be large, which is beneficial for the realization of strongly perturbed resonators enabling the most flexible engineering of the spectral properties of the laser.
|
|
| 8. |
- Adolfsson, Göran, 1981-, et al.
(författare)
-
Spectral engineering of semiconductor Fabry–Perot laser cavities in the weakly and strongly perturbed regimes
- 2010
-
Ingår i: Journal of Optical Society America B. ; 27:1, s. 118-127
-
Tidskriftsartikel (refereegranskat)abstract
- By inserting index perturbations at certain positions along a semiconductor Fabry–Perot laser cavity the threshold 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 properties of the laser. In our approach we fully account for all multiple-reflection events and use a search space that permits any distribution of the locations and lengths of the perturbations. We are therefore able to design cavities with almost arbitrary spectral properties with very low threshold gain values for, e.g., the lasing modes of a two-color cavity. Constraining the design by reducing the geometrical freedom, which can be used to increase the smallest feature size to simplify fabrication, we seamlessly approach the weakly perturbed regime while maintaining much of the freedom for spectral engineering.
|
|
| 9. |
|
|
| 10. |
- Lim, J. J., et al.
(författare)
-
Static and dynamic performance optimisation of a 1.3 mu m GaInNAs ridge waveguide laser
- 2008
-
Ingår i: Optical and Quantum Electronics. - 0306-8919. ; 40:14-15, s. 1181-1186
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, we perform a multi-parameter design study to improve the performance of an uncooled directly modulated 1.3 mu m GaInNAs ridge waveguide laser for high speed operation especially at high temperature. The static and dynamic performance of the improved design is analyzed using an accurate in-house 2D electro-opto-thermal laser simulator. The improved structure is shown to have a lower threshold current, higher thermal roll-over limit and higher modulation bandwidth-especially under high temperature operation. The improved structure also has a lower vertical beam divergence compared to a reference structure with a conventional design.
|
|
