DESIGN OF HIGHER-ORDER ALL OPTICAL BINARY DELTA-SIGMA MODULATOR USING RING LASER

Author

Marji Ayed Alshammari, Southern Illinois University CarbondaleFollow

Date of Award

12-1-2018

Degree Name

Doctor of Philosophy

Department

Electrical and Computer Engineering

First Advisor

Sayeh, Mohammad

Abstract

The aim of this research is to investigate the performance of a bi-stable device using a single active element and to design a higher order all optical binary delta-sigma modulator (BΔΣM). A Delta sigma modulator has two important components that require enhancement to achieve robust modulation. The first component is the integrator which accumulates the error and at the same time leaks it. Here, the integrator is a single ring laser consisting of a semiconductor optical amplifier (SOA) and a filter to allow the light frequency of interest into the ring. The other component is the bi-stable device (called Schmitt trigger) that switches either ON (1) or OFF (0). There are different novel approaches to developing a bi-stable circuit. First, the coupled two ring lasers where each ring suppresses each other. Second, a novel idea that considered as a bi-stable device with single active element to achieve reduced power and reduce cost. This type of circuit is merged ring lasers with using single SOA. This system is modeled and its bistability hysteretic characteristics is investigated. The first bi-stable device is used to construct an all optical BΔΣM with 1st, 2nd and 3rd -order approaches. It performs better when the SOA bulk device is replaced by multi-quantum well (MQW) SOA.