基于双稳态实现具有陡峭阈值的全光比较器

All-optical comparator with sharp threshold based on bistability

提出了一种利用四分之一波长(λ/4)相移分布反馈(DFB)激光器实现全光比较功能的方法,仿真结果表明,该方法可用作吉赫兹超快全光比较判决,实现全光模数转换系统中的编码功能。当外部光注入λ/4相移DFB激光器时,在注入光功率与激光器激射光功率之间会出现双稳态特性,合理选择激光器外部及内部参数(即偏置电流、耦合系数、端面反射率及芯片长度),双稳态会出现陡峭的阈值。分析激光器外部及内部参数对双稳态特性的影响,得到了符合全光比较功能的静态双稳态特性参数空间。

A method is proposed to realize all-optical comparison by utilizing quarter wavelength (λ/4)phase-shifted DFB laser. The simulation results demonstrate that this method can be used in GHz ultra-fast all-optical comparison and achieve the encoding function of all-optical analog-to-digital converting system.Under injection of light,the bistability can be obtained between the in-jected light power and the lasing power.If properly select the parameters outside and inside of the laser,including bias current, coupling coefficient,facet reflectivity and the length of the laser chip,the bistability with a sharp threshold will appear.We ana-lyzed the influence of these parameters on bistability in detail,and get the bistability parameter space which is fit for the realiza-tion for the function of all-optical comparison.