# Training Videos

## Bistable optical devices

This is a continuation from the previous tutorial - nonlinear optical modulators and switches. A bistable device has two stable output states under one input condition. Because of this binary feature, bistable devices can be used for many digital operations, such as switches, memories, registers, and flip-flops. Bistable electronic circuits and devices have become indispensable components in a wide range of application that require the storage of binary information. Bistable optical devices can be important for their applications as optical logic, memories, and analog-to-digital converters in optical signal processing systems. In addition, they can also be used as optical pulse...

## Nonlinear Optical Modulators and Switches

This is a continuation from the previous tutorial - optical frequency converters. In a nonlinear optical modulator, the modulation of an optical wave is accomplished through a nonlinear optical process. A nonlinear optical modulator can be based on either self modulation or cross modulation. In the case of self modulation, only one optical beam is present, and the modulation on the beam is a function of the characteristics of the beam itself. In the case of cross modulation, two or more optical beams are present, and the beam of interest is modulated by one or more other beams that carry...

## Optical Frequency Converters

This is a continuation from the previous tutorial - phase matching for nonlinear optical processes. A very important class of nonlinear optical devices is the optical frequency converters. Nonlinear optical frequency conversion is the only means for direct conversion of optical energy from one frequency to another. Indeed, the discipline of nonlinear optics was born out of the first observation of second-harmonic generation in 1961. There are basically two types of nonlinear optical frequency converters. The majority are based on parametric processes, particularly the parametric second-order processes, that require phase matching. Sum-frequency generators, difference-frequency generators, harmonic generators, and parametric amplifiers...

This is a continuation from the previous tutorial - nonlinear optical interactions. The coupled-wave theory developed in the coupled-wave theory tutorial is used for analysis of nonlinear optical interactions in a homogeneous medium. In nonlinear optical waveguides, coupled-mode theory can be used if there is no mixing between different optical frequencies, but a combination of coupled-wave and coupled-mode formalisms has to be used if there is frequency mixing in the interaction. In applying coupled-wave or coupled-mode theory to the analysis of a nonlinear interaction, the perturbing polarization, generally expressed as $$\Delta\mathbf{P}$$ in the coupled-wave theory tutorial, is identified as the characteristic...