This paper conducts a research on modulation characteristics of blue light-emitting diodes (LEDs) used in a visible-light communication (VLC) system. Through analysis of the modulation characteristics of LEDs with dif...This paper conducts a research on modulation characteristics of blue light-emitting diodes (LEDs) used in a visible-light communication (VLC) system. Through analysis of the modulation characteristics of LEDs with different emitting sizes, we find that there is a similar linear relationship between LED’s 3dB bandwidth and the operation current density. This experiment also shows that high series resistance is one major issue that limits our LED's modulation speed. To further improve the LED bandwidth, the resistance can be reduced by optimizing device layout as well as reducing material bulk resistance. Clearly, this study provides an approach to increase the modulation bandwidth of GaN-based LEDs for VLC systems.展开更多
An efficient technique is used to flatten the spectral response of an arrayed waveguide grating （AWG） multiplexer. By subtracting an increment from the core width of odd arrayed waveguides and by adding the same inc...An efficient technique is used to flatten the spectral response of an arrayed waveguide grating （AWG） multiplexer. By subtracting an increment from the core width of odd arrayed waveguides and by adding the same increment to that of even arrayed waveguides,a box-like spectral response can be obtained. A 17 × 17 polymer AWG multiplexer with box- like spectral response has been made using FPE polymer materials. Measured result for the AWG shows that the box-like spectral response has a 3dB bandwidth of 0. 476nm, the crosstalk is about or less than - 21dB for every output channel,and the insertion loss is 13-15dB.展开更多
文摘This paper conducts a research on modulation characteristics of blue light-emitting diodes (LEDs) used in a visible-light communication (VLC) system. Through analysis of the modulation characteristics of LEDs with different emitting sizes, we find that there is a similar linear relationship between LED’s 3dB bandwidth and the operation current density. This experiment also shows that high series resistance is one major issue that limits our LED's modulation speed. To further improve the LED bandwidth, the resistance can be reduced by optimizing device layout as well as reducing material bulk resistance. Clearly, this study provides an approach to increase the modulation bandwidth of GaN-based LEDs for VLC systems.
基金supported by the National Natural Science Foundation of China(No.60576045)~~
文摘An efficient technique is used to flatten the spectral response of an arrayed waveguide grating （AWG） multiplexer. By subtracting an increment from the core width of odd arrayed waveguides and by adding the same increment to that of even arrayed waveguides,a box-like spectral response can be obtained. A 17 × 17 polymer AWG multiplexer with box- like spectral response has been made using FPE polymer materials. Measured result for the AWG shows that the box-like spectral response has a 3dB bandwidth of 0. 476nm, the crosstalk is about or less than - 21dB for every output channel,and the insertion loss is 13-15dB.
