No signal loss in this optical system

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A model of an optical system in which losses in waveguides are compensated by gain in signal amplitude has been calculated by scientists from the Institute for Theoretical and Applied Electromagnetics of the Russia Academy of Sciences, the All-Russia Research Institute of Automatics and Moscow Institute of Physics and Technology (MIPT).

The newly discovered phenomenon means that a signal can be transmitted with virtually no losses, which up until now is said to have been an unresolved issue with plasmonic and nano-optic devices.

“By periodically changing the distance between the waveguides, it is possible to ‘configure’ the flow of energy between them so that the electromagnetic fields will be amplified as they propagate along the waveguides, even in cases where the losses exceed the gain”, commented Professor Alexander Pukhov, a senior researcher at MIPT.

In optical waveguides, at microelectronic level, there is a problem of energy loss, and consequently a loss of signal, which is a major limiting factor in terms of their application.

The scientists decided to examine parametric perturbation in a system of two coupled waveguides. The researchers took one waveguide with an absorbing medium, and another with an amplifying medium. The intensity of the electromagnetic wave in this system changes periodically, either increasing, or decreasing.

The idea was, at the moment when the intensity of the system reaches a maximum, to change the distance between the waveguides in order to concentrate the field in the waveguide with the amplifying medium, which would further increase the intensity of the signal.

According to the team, by periodically changing the distance between the waveguides, it is theoretically possible to infinitely increase the power.

In addition, there are also claimed to be nonlinear effects that inhibit and limit the growth of the amplitudes. This means that by using the model described it will be possible to create a stable signal that will reliably transmit information in photonic circuits and could be used to develop photonic computers.