Design And Research Of Multi-channel WDM/DWDW Based On Photonic Crystal

With the development of global communication technology,data information has become more and more complex,and the means of transmitting information has encountered great challenges.Wavelength division multiplexers apperaed.The wavelength division multiplexer decomposes a beam of light signals into different wavelengths of light for propagation,and sends the data to specific users.Compared with traditional dielectric devices,devices based on photonic crystals have the characteristics of small size and low loss.In this paper,two photonic crystal WDM/DWDM are designed.The forward input can realize the multi-channel wavelength division demultiplexing function,and the reverse input can realize multi-channel wavelength division multiplexing function.Both of them have the characteristics of low loss,low crosstalk and high transmission efficiency.According to different requirements for information carrying capacity,the two types of multiplexers designed are quasi-dense and dense respectively.The wavelength extraction of the two types of WDM/DWDM structures is realized by applying the coupling effect between the resonant cavity and the waveguide.A compact ring resonant cavity composed of an inner dielectric column and four evenly distributed outer dielectric columns is designed.The structure has a strong local ability on the field.Designed in combination with waveguides,it realizes eight-channel quasi-dense WDM/DWDM.The wavelength interval is 2.2nm,and the average isolation and insertion loss are 33.7dB and-0.33dB,respectively.The minimum quality factor is 1940,and the maximum can reach 6184.Due to the small size of the resonator,the size of the entire device is only 217.8?m~2 in the case of eight channels,so miniaturization is guaranteed.At the same time,the structure has strong scalability.Because the resonant cavity is composed of a central dielectric column and four peripheral dielectric columns,the design freedom of the resonance wavelength is very high,and the wavelength division multiplexer can be expanded without serious degradation of the performance.The eight-channel quasi-dense WDM/DWDM expands into a 16-channel quasi-dense WDM/DWDM.The average isolation and insertion loss are28.7dB and-0.44dB,respectively.In order to further improve the information carrying capacity of division multiplexer,a dense WDM/DWDM is designed.The resonant cavity is a combination structure of ring resonant cavity and point defect resonant cavity,which realizes the dense WDM/DWDM function with a wavelength interval of 0.8nm.The average isolation and insertion loss are 30.1dB and-0.35dB,respectively.The minimum quality factor is 5171,and the maximum can reach 15531.Due to the structure of the combined cavity,the device size is slightly larger than the first WDM/DWDM based on a compact ring cavity.The size of the device is 365.8?m~2.