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A fiber-based vertically emitting semiconductor laser at 850nm

Balocchi, A. and Warburton, R.J. and Kutshera, H.J. and Karrai, K. and Abram, R.H. and Ferguson, A.I. and Calvez, S. and Dawson, M.D. and Riis, Erling (2002) A fiber-based vertically emitting semiconductor laser at 850nm. In: LEOS 2002. The 15th Annual Meeting of the IEEE Lasers and Electro-Optics Society, 2002, 2002-11-10 - 2002-11-14.

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Abstract

The possibility of wavelength tuning and insertion of intra-cavity control elements makes vertical external cavity surface emitting lasers (VECSEL) a useful tool for telecommunication and spectroscopic applications. Very small cavity lengths are desirable for achieving continuous single mode tuning and the fiber-based VECSEL is a simple device which avoids the complicated post-growth processing involved in the fabrication of a membrane-type laser. We report here on the successful operation of an optically-pumped fiber-based VECSEL in the 850 nm wavelength region. The device comprises a half cavity periodic gain structure made of 15 Al0.2Ga0.8As/GaAs quantum wells designed to be at the anti-nodes of the electric field standing wave, with a 30 pairs Al0.2Ga0.8As/AlAs distributed Bragg reflector (DBR) as the bottom mirror. The structure is similar to one previously described, used in a macroscopic external cavity geometry. The top mirror of our cavity is a dielectric DBR deposited onto the cleaved end of a single mode fiber whose distance from the semiconductor can be controlled via a piezoelectric actuator to allow for wavelength tuning. The aim of this work is to contribute to the understanding of the operation of this optically pumped fiber-based laser. By comparing the laser performance with the f finesseinesse of an empty cavity with otherwise identical geometry, we are able to conclude that the dominant photon loss mechanism is due to fundamental diffraction limits.