Frankfurt 2006 – wissenschaftliches Programm

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Q: Quantenoptik und Photonik

Q 20: Photonische Kristalle I

Q 20.8: Vortrag

Dienstag, 14. März 2006, 12:25–12:40, HI

Single mode photonic-crystal distributed feedback lasers — •Holger Hofmann, Helmut Scherer, Stefan Deubert, Johann-Peter Reithmaier, Martin Kamp, and Alfred Forchel — Technische Physik, Am Hubland, D-97074 Würzburg, Germany

High power single-mode emission with diffraction-limited beam quality is advantageous for many applications such as optical fiber amplifiers, frequency doubling or optical sensors. We investigate a widely unexplored approach to achieve these objectives in semiconductor lasers: The Photonic-Crystal distributed-feedback (PCDFB) laser, which combines the best features of conventional DFB and α-DFB lasers in order to achieve single-mode emission and good beam quality over a broad range of apertures [1].

A PCDFB laser uses a rectangular, 2D photonic crystal lattice for optical feedback. This lattice, in our case realized as an array of etched air holes, is tilted with respect to the cleaved facets of the device. The laser light has to undergo multiple Bragg reflections during a roundtrip in the cavity, which leads to the selection of a single lateral and longitudinal mode.

We use InGaAs/AlGaAs laser layers for the fabrication of the devices. The air holes are defined by e-beam-lithography and dry etching through the upper cladding and close to the waveguid layer. We observe single mode emission at wavelengths around λ = 980nm with a sidemode supression of over 30dB.

[1] I. Vurgaftman and J.R. Meyer, Appl. Phys. Lett. 78, 1475 (2001)