We report on a numerical investigation of the effect of self-steepening on the dynamics of a passively modelocked
fiber laser containing a long period fiber grating. The numerical model is based on the normalized complex
Ginzburg-Landau equation and the nonlinear coupled mode equations of the grating. The nonlinear dynamics of
the laser are observed through plotting the pulse energy against the linearly increasing gain so obtaining bifurcation
diagrams. The inclusion of self-steepening was found to result in a temporal walk-off with no significant
pulse width or energy alternations, while exhibiting different regions of period doubling bifurcation.
We report on an object-oriented based simulation of a passively modelocked fiber laser containing a long period
fiber grating. Object oriented concepts, such as polymorphism, encapsulation, operator overload and delegation
can be used effciently to implement extendable and reusable C++ code for scientific computing. It was found
that decreasing the level of encapsulation reduces the computational time. The numerical model is based on the
normalized complex Ginzburg-Landau equation and the nonlinear coupled mode equations of the grating. The
modelocked pulse energy was found to exhibit a wide range of nonlinear dynamics. To accurately capture these
dynamics highly robust and numerically stable variations of the split step Fourier method were implemented.
The dynamical behavior of the nonlinear optical loop mirror (NOLM) with feedback and low birefringence twisted fiber in the loop is examined. It is found that the output of the NOLM with feedback depends on many parameters, including the fiber beat length, the polarization state of the counter-propagating beams in the loop, as well as the length, twist rate, and nonlinearities of the loop fiber. The placement of a quarter-wave plate (QWP) asymmetrically in the loop allows for the tuning of the bistable and chaotic output from the optical resonator. As well, the output polarization state of the NOLM with feedback is shown to rely on the QWP angle as well as the input power, which is of importance when using the NOLM with feedback in optical systems that have polarization sensitivity. As all fibers exhibit some degree of twist and birefringence, the addition of a QWP in the NOLM with feedback allows for an easy and practical measure of control of the bistable and chaotic regions of the nonlinear optical resonator, which is important when implementing the device in an optical system.
A new graduate level course on the 'Simulation of Optical Fibre Systems' has been developed and presented for the first time within the Ottawa Carleton Institute of Electrical and Computer Engineering. The course was intended as a bridge between the areas of CAD and photonics. The course focuses on numerical techniques as well as the optics, for example, part of the course includes details on the use of finite difference techniques as well as the split-step Fourier method to solve the nonlinear Schrödinger equation (which is used to simulate pulse propagation in optical fibre). Simulation work for the first part of the course was using Matlab (for example, examining modes in fibre and examining pulse propagation), then Optisystem was used for the later part (for example, looking at dispersion compensation and WDM systems). The course was intended not to be a first course in optical fibre communications and so requires completion of a prerequisite course which covers appropriate material, or relevant experience. Details of the course are presented and discussed.