波长间隔为3.2nm的电光调制和波分复用集成器件研究

An Integrated Device for Electro-optic Modulation and Wavelength Division Multiplexing with the Wavelength Channel Spacing of 3.2nm

提出了一种基于光子晶体电光调制和波分复用的集成器件。该集成器件的电光调制器模块和波分复用器模块均采用一维光子晶体纳米梁腔结构。利用三维时域有限差分法进行仿真。结果表明,该器件可实现工作波长为1550.4 nm和1553.6 nm的电光调制和波分复用功能。该器件在工作波长1550.4 nm和1553.6 nm下的插入损耗分别为0.89 dB和0.40 dB,消光比分别为17.13 dB和22.52 dB,调制深度分别为0.98和0.99,信道串扰分别为-24.20 dB和-23.37 dB,器件尺寸仅为71.34μm×7.8μm×0.22μm。该集成器件结构紧凑,易于集成,可望应用于光互连网络和数据中心。

In recent years,the internet has been used in almost every aspect of life,and the demands for communication capacity and transmission speed are increasing.The unit device technology has basically matured,but how to maintain the good performance of unit devices and place multiple devices on the same chip to solve the bottleneck of the current communication system is still under study.Nowadays,electrooptical modulators and wavelength division multiplexers with various structures have been proposed.Research on these two types of single devices has become increasingly mature,but there are few studies on silicon-based optoelectronic integration that integrating the two devices to achieve multiple functions,which means more research on integrated devices is still needed.Considering the requirements of optical inter-connected networks and data centers for small size,large bandwidth and integration,we propose an on-chip integrated device for electro-optic modulation and wavelength division multiplexing.The two devices are cascaded together using silicon waveguides,which has the characteristics of small size,small modulation voltage,low insertion loss,low channel crosstalk and large modulation depth.In this paper,an integrated device based on photonic crystal nanobeam cavity electro-optical modulator and wavelength division multiplexer is proposed.Both the electro-optical modulator module and the wavelength division multiplexer module are composed of a one-dimensional photonic crystal nanobeam cavity.The integrated device consists of nanowire silicon waveguide,one-dimensional photonic crystal nanobeam cavity,Al electrode,and silicon dioxide cladding.Among them,the nanowire silicon waveguide,the one-dimensional photonic crystal nanobeam cavity,and the Al electrode are located in the silicon dioxide cladding.The whole integrated device can realize the"on"and"off"state modulation of different wavelengths of the electro-optical modulation module and download different wavelengths through the wavelength division multiplexing module.In this paper,simulation analysis is carried out based on the FDTD module and Device module in the commercial optical simulation software Lumerical.First of all,by analyzing the side-coupling structure of the one-dimensional photonic crystal nanobeam cavity,the parameters affecting its transmittance and resonance wavelength are found.Afterwards,based on the plasmonic dispersion effect,wavelength modulation is realized through the nanobeam cavity and the PN junction to complete the design of the electro-optic modulation module.Then based on side-coupling theory,wavelength division multiplexing is realized through the nanobeam cavity to complete the design of wavelength division multiplexer module.In the end,the two modules are integrated together.Since the resonant wavelength of the nanobeam cavity will shift after integration,the nanobeam cavity is fine-tuned to complete electro-optic modulation and wavelength division multiplexing at 1550.4 nm and 1553.6 nm.The integrated device has great performance.It has small modulation voltage.When the modulation voltage is 1.25 V,the change in electron concentration ΔN_(e) reaches 1.58×10^(18)cm^(-3),and the change in hole concentrationΔN_(h) reaches 1.95×10^(18)cm^(-3),which can realize the modulation of the wavelength.According to the simulation,the transmittances of 1550.4 nm and 1553.6 nm in the"on"state are 81.50%and 91.21%,and the transmittance of 1550.4 nm and 1553.6 nm in the"off"state are 1.58%and 0.51%,respectively.It can be calculated that the total insertion loss is less than 0.89 dB,the extinction ratio is greater than 17 dB,the modulation depth is greater than 0.98,and the channel crosstalk values are all less than-23 dB,which indicates the modulation and wavelength division of the device has good performance.Compared to previous research results,it is no longer a single-function device.Compared to other integrated devices proposed in table 2,the wavelength interval of the integrated device proposed in this paper is smaller,and the modulation voltage is also lower,only 1.25 V.In addition,the structure size of the integrated device is smaller,which is beneficial to large-scale on-chip integration.In conclusion,an integrated device based on photonic crystal one-dimensional nanobeam cavity electro-optical modulator and wavelength division multiplexer is proposed,which realizes"on"and"off"state modulation and wavelength downloading at 1550.4 nm and 1553.6 nm.The insertion loss of the device at the working wavelengths of 1550.4 nm and 1553.6 nm are 0.89 dB and 0.40 dB,respectively.The extinction ratio is 17.13 dB and 22.52 dB.The modulation depth is 0.98 and 0.99 and the channel crosstalk is-24.20 dB and-23.37 dB,respectively.The footprint is 71.34μm×7.8μm×0.22μm.The integrated device has large modulation depth,low insertion loss,high extinction ratio and low channel crosstalk.It also has a compact structure and is easy to be integrated,which can be used in optical interconnected networks and data centers.