Opt Quant Electron (2008) 40:69–81 DOI 10.1007/s11082-007-9154-9 Spectral properties of edge-emitting semiconductor laser subject to optical feedback from extremely short external cavity Mikel Arizaleta Arteaga · Manuel López-Amo · Javier Hernández · Krzysztof Koltys · Andrzej Tabaka · Hugo Thienpont · Krassimir Panajotov Received: 10 July 2007 / Accepted: 16 November 2007 / Published online: 6 December 2007 © Springer Science+Business Media, LLC. 2007 Abstract We experimentally and theoretically study the impact of optical feedback from an extremely short external cavity (tens of μ m) on the spectral behavior of edge emitting lasers (EELs). We are able to investigate a broad range of external cavity lengths and feed- back strengths, by using a nanometer precision movable mirror attached to a fiber facet. A discrete modulation of the wavelength of operation is observed and its amplitude depends on the external cavity length and the external mirror reflectivity. We show that it is possible to optimize the tuning range of such a discrete wavelength tunable laser with respect to the external cavity and laser parameters. Keywords Optical feedback · Edge emitting laser · Tunable · External cavity 1 Introduction The effect of optical feedback on the spectral properties of edge emitting lasers (EELs) has been widely studied. Indeed, linewidth broadening or narrowing, mode hopping, and coher- ence collapse have been reported (Tkach and Chraplyvy 1986; Miles et al. 1980; Lenstra et al. 1985; Lang and Kobayashi 1980; Patzak et al. 1983) in EEL subject to optical feedback from a short or long external cavity. Complex dynamics in such systems have been also studied and they show, e.g., sustained periodic oscillations, quasiperiodic and chaotic dynamics (Mork et al. 1992; Masoller and Torre 2005; Erneux et al. 2002). M. Arizaleta Arteaga (B ) · M. López-Amo Department of Electrical and Electronic Engineering, Universidad Pública de Navarra, 31006 Pamplona, Navarra, Spain e-mail: mikel.arizaleta@unavarra.es M. Arizaleta Arteaga · J. Hernández · K. Koltys · A. Tabaka · H. Thienpont · K. Panajotov Department of Applied Physics and Photonics, Vrije Universiteit Brussel, 1050 Brussels, Belgium K. Panajotov Institute of Solid State Physics, 1784 Sofia, Bulgaria 123