High-speed modulation from the fast mode extraction of a photonic crystal light-emitting diode

Abstract

Using light-emitting diodes (LEDs) for visible light communication has become an alternative choice of radio source due to channel crowding of the radio-frequency (RF) signal. The modulation bandwidth of LEDs is usually limited by the spontaneous carrier lifetime in multiple quantum wells. Here, sub-GHz modulation of GaN-based LED employing photonic crystal (PhC) nanostructure is demonstrated. The guided photonic modes of the LEDs are modulated by the RF signal. Both carrier lifetime of lower- and higher-order modes are studied in time-resolved photoluminescence (TRPL) at room temperature. The f-3dB-J curve of the PhC LED exhibits a higher bandwidth than the typical LED structure. At 11.41 kA/cm2, the optical −3-dB bandwidth (f-3dB) up to 234 MHz of the PhC LED (PhCLED) is achieved. Our studies on TRPL at different wavelengths and frequency response at different injection current densities conclude that the higher operation speed is attributed to faster radiative carrier recombination of extracted guided modes from the PhC nanostructure.