Modeling and Simulation of Superluminescent Light-Emitting Diodes (SLEDs)

The availability of analytical models and numerical simulation tools is inevitable for the development and optimization of broadband high-power superluminescent light-emitting diodes (SLEDs) and its applications. In this paper, various theoretical aspects of SLEDs are discussed, which are important for the successful design of new devices with superior performance. We study the suppression of residual facet reflections as well as the importance of a careful vertical waveguide design. Furthermore, a simple analytical model for the L-I characteristics of SLEDs is developed that is based on a power law with an exponent that is dependent on the chip length. The theoretical model is verified by a comparison with experimental results of a broadband SLED operating in the wavelength region around 1300 nm. It is shown that the model can be also used to extract important simulation parameters from measured L-I characteristics. Finally, results are presented for an improved high-performance SLED structure in the same wavelength region with output powers of more than 50 mW and a 10-dB spectral bandwidth beyond 100 nm.