| 1. |
- Borgentun, Carl, 1979, et al.
(författare)
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Optically pumped high-power semiconductor disk laser with gain element engineered for wide tunability
- 2010
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9780819481931 ; 7720:1, s. 772014-8
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The layer structure of the gain element in an optically pumped semiconductor disk laser (OP-SDL) was designed for wide tunability. This was achieved by a parametric optimization of the structure, which in effect balanced the spectrally varying influence of the gain of the quantum wells, the longitudinal distribution of the standing wave lasing field in the structure, and the degree of resonance in the subcavity formed between the distributed Bragg reflector at the bottom and the air-semiconductor interface at the top. The quality measure in the optimization was the spectral reflectance of the gain element for light incident from the external cavity at low power. This unsaturated reflectance was compared to its target function, which was constant at a specified value larger than unity over a wide, prescribed wavelength range. The fabricated gain element was used in a linear OP-SDL with a rotatable intra-cavity birefringent filter for wavelength tuning. The design principles for achieving wide tunability were experimentally validated by the strong agreement between measurements and simulations of the spectral threshold pump intensity. Furthermore, tuning experiments at high pump powers were performed showing that the lasing wavelength could be tuned from 967 nm to 1010 nm with a maximum output power of 2.6 W.
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| 2. |
- Yu, Xingang, et al.
(författare)
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Single-mode InGaAs/GaAs 1.3-mu m VCSELs Based on a Shallow Intracavity Patterning
- 2010
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Ingår i: SEMICONDUCTOR LASERS AND LASER DYNAMICS IV. - : SPIE. - 9780819481931 ; , s. 772021-
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Konferensbidrag (refereegranskat)abstract
- A high-power single-mode 1.3-mu m InGaAs/GaAs vertical-cavity surface-emitting laser (VCSEL) structure employing a novel concept of engineering the optical mode profile to match the gain profile is suggested and demonstrated experimentally and theoretically. In contrast to various singlemode VCSEL approaches reported in the literature so far, based on selective loss or anti-resonant effects to suppress higher order modes, it is due to a novel design to increase the active region size while maintaining single mode emission. The shape of the fundamental mode profile is engineered to be similar to the gain profile which resembles a doughnut shape especially in intra-cavity contacted devices. In this way, the fundamental mode with the best fit to the gain profile can reach the lasing condition earliest and consume all the optical gain, leading to a suppression of higher order modes. Notably, despite this engineered shape of the mode profile, the far field shape remains close to Gaussian. The mode shaping can be achieved by introducing a shallow intracavity patterning before depositing the top mirror. Fabricated device structures consist of a A-Si/SiN/SiO(2) top mirror, modulation-doped current spreading layers, re-grown current confinement layers, three InGaAs/GaAs quantum wells, and a GaAs/AlGaAs bottom mirror. Single mode operation is demonstrated even for devices with active region as large as 10 mu m.
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