Date of Award

3-10-2008

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Engineering Physics

First Advisor

Thomas A. Niday, PhD

Abstract

Diode lasers are useful in military and commercial applications that have strict requirements for size, weight and power. This includes the use of diode lasers in optoelectronic and photonic integrated circuits, which can lead to new technologies in optical communications and optical interconnects in high performance computing systems. For these systems to be effective, the diode laser must be modulated at frequencies beyond current limits which are typically a few GHz. This barrier can be broken by optically coupling a diode laser with a similar laser. A set of single mode rate equations models the dynamics of twin optically coupled diode lasers. Steady states of the system are derived analytically or calculated numerically when an analytic expression is not easily available. The stability of the steady states is examined by using a linear stability analysis, which is also used in an algorithm that calculates the infinitesimal modulation response. The modulation response is also calculated by using a numerical method that directly integrates the rate equations. Typical parameters for an InGaAsP diode laser are used in the algorithms to investigate mutual coupling and evanescent coupling. It will be shown that mutually coupled lasers can be effectively modulated out to frequencies of approximately 9 GHz compared to 4 GHz for a solitary laser. For evanescent coupling, the steady states are unstable over large regions of the parameter space, but this is remedied by introducing asymmetric DC currents through the lasers or by introducing the effects of gain saturation. With stable steady states, evanescently coupled lasers can be effectively modulated at frequencies out to about 30 GHz which is more than a seven fold improvement over a solitary laser.

AFIT Designator

AFIT-GAP-ENP-08-M05

DTIC Accession Number

ADA483257

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