In recent years, there has been significant interest in applying the new and developing photonics technology for telecommunications switching. As the transmission plant has converted its facilities to fiber, there is an economic interest in completing the optical path through the switching system to the terminal facilities without requiring optical-to-electrical conversions. Several devices have emerged within the past few years that are capable of meeting this goal. These devices can be categorized according to the function they perform into two major classes. The first of these classes, called relational devices, performs the function of establishing a relationship or mapping between the inputs and outputs. This relationship is a function of the control signals to the device and is independent of any signal or data inputs. The second class of device is called logic devices, in these devices, the data or information carrying signal that enters the device controls the state of the device so that a Boolean function or combination of Boolean functions is performed on the inputs.
© 1988 Optical Society of AmericaPDF Article