High-Speed Nonpolar InGaN/GaN Superluminescent Diode With 2.5 GHz Modulation Bandwidth

This is the authors' abstract. We don't add key points for this paper.

We demonstrate a superluminescent diode fabricated on a nonpolar m-plane GaN substrate by employing a linearly tapered waveguide design. A high electrical -3dB modulation bandwidth ( f3dB) of 2.5 GHz at a current density of 30 kA/cm2is achieved. The high modulation bandwidth is attributed to the shorter carrier recombination lifetime, the linear gain curve in the nonpolar m-plane quantum wells, and the ability to operate at high current densities while effectively suppressing lasing. We derive a general expression for the -3dB bandwidth as a function of current density for SLDs using a similar approach to that for laser diodes. The -3dB bandwidth of a nonpolar superluminescent diode increases exponentially with current density. The experimental results are consistent with the derived expression for f3dBvs. current density.