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Basic Research On Linearization Of Silicon Based Optical Modulator

Posted on:2021-01-18Degree:MasterType:Thesis
Country:ChinaCandidate:S J FanFull Text:PDF
GTID:2428330623968489Subject:Engineering
Abstract/Summary:PDF Full Text Request
Silicon-based optical modulator can be processed and prepared by microelectronic integrated platform,which has the advantage of large-scale production,so it becomes an important research direction,and begins to be applied in the conventional optical communication system which mainly transmits digital signals.With the rapid development of microwave photonic link which mainly transmits analog signal,the simulation performance of optical modulator is paid more attention.The linearity of optical modulator directly determines whether the signal in the link can be transmitted with high fidelity.Linear modulation has become a research hotspot.In this paper,the modulation linearization of integrated silicon-based light modulator is studied.Firstly,the linear optimization method of silicon optical modulator based on carrier dispersion effect is fully discussed and verified in the modulation structure.Secondly,the linearization scheme of parallel Mach Zehnder?MZ?structure and micro ring assisted MZ structure is theoretically studied in the optical structure.Finally,a silicon micro ring assisted MZ modulator with voltage fine-tuning coupling coefficient is studied and designed.Firstly,the carrier dispersion effect of silicon and the modulation principle of MZ structure are analyzed.It is shown that the nonlinear distortion of silicon optical modulator mainly comes from PN junction modulation structure and MZ structure.The third-order intermodulation distortion is the most important factor of linearity.After that,we introduce the measurement index of linearity,the analysis method of modulation waveguide structure and the finite difference time domain method of electromagnetic field simulation.Then,in this paper,five linear optimization methods are discussed,including optimizing the PN junction modulation mode,doping mode,doping concentration in the modulation region,modulation region offset and bias voltage.The simulation results show that the maximal spurious-free dynamic range without spurious can reach109.3dB?Hz2/3/3 by setting the above five modulation parameters reasonably.After that,this paper studies the linearization scheme of silicon optical modulator using parallel MZ structure and modulation power distribution method,and verifies that the maximal spurious-free dynamic range is 123.9dB?Hz4/5.Finally,based on the MZ structure and the micro ring structure,this paper studies the linearization scheme of the micro ring assisted MZ modulation.The results show that when the coupling efficiency or coupling coefficient reaches a specific value,the third-order nonlinear relationship between the phase response of the micro ring structure and the MZ structure can cancel each other and improve the spurious-free dynamic range.At the end of this paper,aiming at the above-mentioned linearization scheme,a silicon micro ring assisted MZ structure with voltage fine-tuning coupling efficiency is designed.The specific design parameters are given,and the feasibility of the design is verified by simulation.This paper also discusses the linearization scheme of double microring assisted MZ modulation.Based on this scheme,the spurious-free dynamic range can reach 126.7dB?Hz4/5.
Keywords/Search Tags:Silicon optical modulator, Carrier dispersion effect, Spurious-free dynamic range, Microring assisted MZ structure
PDF Full Text Request
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