David Sackett

Abstract

Most continuous wave laser diodes display varying degrees of self-sustained pulsation (SSP). This pulsation is due to an inhomogeneous cavity. Most SSP investigations have focused on 780 ran laser diodes. In general, SSP is considered a source of high frequency noise. SSP has, however, been used as a subcarrier for multiplexing. This thesis examines SSP characteristics in 1300 nm laser diodes. A 1300 nm SSP laser diode can be used to create a Subcarrier Multiplexing (SCM) Network. The 1300 and 780 nm SCM networks can be fiber spliced to create a Wavelength Division Multiplexing SCM network (WDM-SCM). The SSP laser diodes studied are "off the shelf and have not been modified to enhance their SSP. 1300 nm Mitsubishi laser diodes are found to have very weak SSP. The SSP was characterized with large linewidths (300MHz), unstable bias regions, and low pulsation amplitude (<1 modulation). Electrical feedback was added to improve the self-pulsation characteristics. Feedback sustained pulsation (FSP) is found to narrow pulsation linewidth (10kHz), increase stability, and increase pulsation amplitude (95% modulation). However, FSP from these laser diodes demonstrated little frequency tuning and non-linear amplitude tuning. The weak FSP carrier modulation is shown to be linked to the weak SSP characteristics. Even though these laser diodes are unsatisfactory for analog subcarrier modulation, FSP digital amplitude modulation remains possible.

Library of Congress Subject Headings

Pulse techniques (Electronics); Laser pulses, Ultrashort; Digital communications

Publication Date

10-1-1997

Document Type

Thesis

Department, Program, or Center

Electrical Engineering (KGCOE)

Advisor

Li, Guifang

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: TK7872.P8 S23 1997

Campus

RIT – Main Campus

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