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Research on ultra-fast optical bistable devices with multi-dimentional quantum well structure

多维量子阱结构超快光学双稳态器件研究

基本信息

批准号：
01460081
负责人：
KAWAGUCHI Hitoshi
金额：
$ 3.26万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

We have investigated the following three topics as a basic research on ultra-fast optical bistable devices with a multi-dimentional quantum well structure.(1) Optical nonlinearities of Al_2O_3 glasses with CdS microcrystallitesWe fabricated Al_2O_3 glasses with CdS microcrystallites by means of the sol-gel method, and investigated their linear and nonlinear optical characteristics. The shift in the wavelength of the absorption edge through a quantum size effect was clearly observed for the CdS-doped Al_2O_3 prepared by changing the annealing temperature. A large nonlinear absorption and refractive index were obtained because a high CdS microcrystallite concentration was achieved through the sol-gel method.(2) Mode-locking of laser diodesTwo types of method for active mode locking of laser diodes (LDs) have been investigated. The first method is a pulse generation from optically coupled LDs. Two LDs, haveing an anti-reflection coating on one facet, were mutually optically coupled, and f … More orm an external cavity (cavity length L_<e x t>). By setting the phase difference in the moduration currents to pi rad (frequency- c/2L_<e x t>) injected into the two LDs, a pulse duration of as short as 7.2ps has been achieved with relatively high optical power (peak power - 170mW) from 1.3 mum InGaAsP/InP LDs. The second is a pulse generation from an external cavity LD by optical pulse pumping. An optical pulse train generated by a gain-switched LD was injected into a LD with an external cavity (slave LD) which was biased just below the laser threshold. The wavelength of the injected optical pulse was chosen to be slightly shorter than that of the slave LD. When the repetition rate of the optical injection pulse was nearly equal to the round trip time of the external cavity, the slave LD showed stable mode locking with the shorter pulse duration than that of pumping pulse.(3) Polarization-bistable laser diodesWe have proposed a new from of pitchfork-bifurcation-like polarization bistability in laser diodes (LD's) that has major speed advantages over conventional S-shaped polarization bistability. From the rate-equation analysis, it has been shown that flip-flop operation with bit rates of higher than 50Gbits/s may be achieved. Less

作为多维量子阱结构超快光学双稳器件的基础研究，我们开展了以下三个方面的工作：(1)含CdS微晶的Al_2O_3玻璃的光学非线性我们采用溶胶-凝胶法制备了含CdS微晶的Al_2O_3玻璃，并对其线性和非线性光学特性进行了研究。通过改变退火温度制备的硫化镉掺杂Al_2O_3，通过量子尺寸效应明显地观察到吸收边波长的移动。通过溶胶-凝胶法获得了较高的CdS微晶浓度，获得了较大的非线性吸收和折射率。(2)激光二极管锁模研究了激光二极管主动锁模的两种方法。第一种方法是从光耦合LD产生脉冲。在一个面上具有减反射膜的两个LD相互光学耦合，并且f…更多的是外腔(腔长L)。通过将调制电流的相位差设置为注入两个LD的pi rad(频率-c/2L；t；e x t&gt；)，从1.3um InGaAsP/InP激光器获得了较高的光功率(峰值功率-170 mW)，脉冲宽度低至7.2ps。第二种是通过光脉冲泵浦从外腔LD产生脉冲。由增益开关LD产生的光脉冲序列被注入到具有外腔(从LD)的LD中，该外腔的偏置略低于激光阈值。注入光脉冲的波长被选择为比从LD的波长略短。当注入光脉冲的重复频率接近于外腔的往返时间时，从激光器表现出稳定的锁模，其脉冲宽度比泵浦脉冲的脉冲宽度更短。(3)偏振双稳半导体激光器我们提出了一种新的半导体激光器(LD)中的叉叉型偏振双稳，它比传统的S型偏振双稳具有更大的速度优势。从速率方程分析表明，可以实现码率高于50Gbit/S的触发器操作。较少