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Q: Fachverband Quantenoptik und Photonik
Q 61: Laserentwicklung: Halbleiterlaser
Q 61.3: Talk
Friday, March 6, 2009, 11:00–11:15, VMP 8 HS
Intensity noise of polarisation stablized VCSELs — •Andreas Molitor1, Martin Blazek1, Johannes Michael Ostermann2, Rainer Michalzik2, and Wolfgang Elsäßer1 — 1Institute of Applied Physics, Darmstadt University of Technology, Schloßgartenstr 7, 64289 Darmstadt, Germany — 2Institute of Optoelectronics, University of Ulm, Albert-Einstein-Allee 45, 89069 Ulm, Germany
VCSELs are reliable, low-cost light sources for optical datacom applications. Etching a grating into the surface Bragg mirror enables polarisation control [1]. We experimentally investigate the intensity noise properties of VCSELs with different surface grating parameters.
For well-selected grating parameters [2], Orthogonal Polarisation Suppression ratios of greater than 20 dB and spectra Sidemode Suppression ratios up to 30 dB are achieved. The Intensity noise is measured via a direct detection setup. For various pump currents radiofrequency spectra of the photo current are recorded and normalized to the Shot Noise level. The influence of the surface grating on the intensity noise behavior is investigated by polarisation resolved measurements. For the surface grating VCSELs we find a noise reduction in the strong polarisation of more than 10 dB compared to a reference VCSEL without grating. The influence of the polarisation and spatial mode structure on the intensity noise will be discussed in detail with respect to theory.
[1] J.M. Ostermann et al., Opt. Commun 246, 511 (2005)
[2] C. Fuchs et al., IEEE J. Quantum Electron. QE-43, 1227 (2007)