Near-Infrared Ultrawide Bandwidth LEDs Using InAs Quantum Dots of Equally Tuned Heights

Ultrawide bandwidth light-emitting diodes (LEDs) using eight layers of InAs/GaAs quantum dots (QDs) of equally tuned heights are reported. Tilted and tapered waveguides of various dimensions are tested under continuous-wave operation conditions. An emission spectrum with 3-dB bandwidth up to 173 nm at a peak wavelength of 1064.5 nm is achieved. The measured emission spectra of the QDs-LEDs as a function of the injection current indicated that the obtained large bandwidth is related to the contribution of the excited states (p, d) from the ensemble of the dots to the recombination mechanism. Continuous-wave output power of 0.6 mW is measured in the corresponding device that is made of a 1-mm-long waveguide and with tilted and tapered angles of 6° and 2°, respectively.