Design And Research Of An Electro-Absorption Modulator Based Integrable Coherent Optical Network Unit

With the rapid increase of backbone network speed,how to increase access network speed has become a technical problem to be solved.Different from the traditional WDM-PON technology,UDWDM-PON technology has the advantages of high flexibility and high sensitivity.The transmission bandwidth can be ensured when the number of access users increases significantly.On the other hand,integrated optical network units have good market prospects.This article is based on UDWDM-PON technology to design and analyze integrable coherent optical network units.The main work is as follows:1.Build a 40 Gb/s ASK full duplex coherent optical access network based on EAM.Using a monolithic DFB-EAM as the upstream optical transmitter to generate ASK optical signals.The transmission performance of direct detection and coherent detection schemes is compared and analyzed.At the same forward error correction bit rate level,the receiving sensitivities of coherent detection for bidirectional downstream and upstream reach-32.51 d Bm and-29.76d Bm,respectively.Compared to direct detection,there is an improvement of 14.20 d B and11.82 d B,which will significantly reduce system power consumption caused by compensation loss.2.Build a 10 Gb/s DQPSK-ASK full duplex coherent optical access network based on MZM.The working interval of downstream modulator EAM is optimized,and coherent modulation and demodulation are performed under the optimal conditions V_bias=-1 V,V_pp=2 V The results show that the receiving sensitivities of the full duplex downstream and upstream reach-43.22 d Bm and-42.26 d Bm,respectively.The high sensitivity can compensate for the high loss caused by the introduction of power distribution in UDWDM-PON systems.3.Build a 100 Gb/s 16QAM duplex coherent optical network based on an arbitrary waveform generator,use dual-arm MZMs to form the IQ modulator,and balance detection scheme was used at the signal receivier.The results show that after 20 km of fiber transmission,the receiving sensitivities of downstream and upstream signals are-31.41 d Bm and-30.64 d Bm,respectively,improving the signal reception capability of current commercial transmission links.In summary,this paper uses EAM,MZM and other optoelectronic devices to design optical network units,and compares the generation and coherent receiving schemes of optical signals under different modulation formats.The flexibility of ONUs is ensured while the signal transmission rate is improved,which provides a technical reference for large-scale deployment of access network.