Laino, Valerio and Roemer, Friedhard and Witzigmann, Bernd and Lauterbach, Christoph and Schwarz, Ulrich T. and Rumbolz, Christian and Schillgalies, Marc O. and Furitsch, Michael and Lell, Alfred and Haerle, Volker (2007) Substrate modes of (Al,In)GaN semiconductor laser diodes on SiC and GaN substrates. IEEE JOURNAL OF QUANTUM ELECTRONICS, 43 (1). pp. 16-24. ISSN 0018-9197, 1558-1713
Full text not available from this repository. (Request a copy)Abstract
In semiconductor laser diodes layers with high refractive index can act as parasitic waveguides and cause severe losses to the optical mode propagating in the longitudinal direction. For (Al,In)GaN laser diodes, the parasitic modes are typically caused by the SiC or GaN substrate or buffer layers, hence the name substrate modes. A set of four different experiments shows the effect of substrate modes in the near-field (the most direct evidence of substrate modes), as side lobes in far-field, oscillations of the optical gain spectra, and as dependency of threshold current on n-cladding thickness. We derive several basic properties of the substrate modes by simple estimates. For a quantitative analysis we employ a 2-D finite element electromagnetic simulation tool. We simulate periodic variations in the cavity gain spectrum that explain the measurements in terms of absolute value and oscillation amplitude. We show that it is necessary to include the refractive index dispersion in order to get the correct period of the gain oscillations. Furthermore, we use the simulations to optimize the laser diode design with respect to substrate mode losses within the constraints given, e.g., by growth conditions.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | QUANTUM-WELL LASERS; OPTICAL-CONSTANTS; REFRACTIVE-INDEX; DOT LASERS; ZINC-OXIDE; GAIN; TEMPERATURE; FIELD; ALXGA1-XN; SPECTRA; blue laser; gallium nitride; substrate modes |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Ulrich Schwarz |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 12 Jan 2021 09:23 |
| Last Modified: | 12 Jan 2021 09:23 |
| URI: | https://pred.uni-regensburg.de/id/eprint/33426 |
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