An optical transistor, also known as an optical switch or a light valve, is a device that switches or amplifies optical signals. Light occurring on an optical transistor's input changes the intensity of light emitted from the transistor's output while output power is supplied by an additional optical source. Since the input signal intensity may be weaker than that of the source, an optical transistor amplifies the optical signal. The device is the optical analog of the electronic transistor that forms the basis of modern electronic devices. Optical transistors provide a means to control light using only light and has applications in optical computing and fiber-optic communication networks. Such technology has the potential to exceed the speed of electronics, while conserving more power.
The fastest demonstrated all-optical switching signal is 900 attoseconds (attosecond =10^-18 second), which paves the way to develop ultrafast optical transistors.
Since photons inherently do not interact with each other, an optical transistor must employ an operating medium to mediate interactions. This is done without converting optical to electronic signals as an intermediate step. Implementations using a variety of operating mediums have been proposed and experimentally demonstrated. However, their ability to compete with modern electronics is currently limited.
Optical transistors could be used to improve the performance of fiber-optic communication networks. Although fiber-optic cables are used to transfer data, tasks such as signal routing are done electronically. This requires optical-electronic-optical conversion, which form bottlenecks. In principle, all-optical digital signal processing and routing is achievable using optical transistors arranged into photonic integrated circuits. The same devices could be used to create new types of optical amplifiers to compensate for signal attenuation along transmission lines.
A more elaborate application of optical transistors is the development of an optical digital computer in which signals are photonic (i.
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Silicon photonics is the study and application of photonic systems which use silicon as an optical medium. The silicon is usually patterned with sub-micrometre precision, into microphotonic components. These operate in the infrared, most commonly at the 1.55 micrometre wavelength used by most fiber optic telecommunication systems. The silicon typically lies on top of a layer of silica in what (by analogy with a similar construction in microelectronics) is known as silicon on insulator (SOI).
Optical computing or photonic computing uses light waves produced by lasers or incoherent sources for data processing, data storage or data communication for computing. For decades, photons have shown promise to enable a higher bandwidth than the electrons used in conventional computers (see optical fibers). Most research projects focus on replacing current computer components with optical equivalents, resulting in an optical digital computer system processing binary data.
A photonic crystal is an optical nanostructure in which the refractive index changes periodically. This affects the propagation of light in the same way that the structure of natural crystals gives rise to X-ray diffraction and that the atomic lattices (crystal structure) of semiconductors affect their conductivity of electrons. Photonic crystals occur in nature in the form of structural coloration and animal reflectors, and, as artificially produced, promise to be useful in a range of applications.
The physics of optical communication components and their applications to communication systems will be covered. The course is intended to present the operation principles of contemporary optical comm
Students understand and apply the physics of the interaction of light with semiconductors. They understand the operating mechanism of scaled photonic devices such as photodetectors, LEDs and lasers, a
This course introduces the principles of nonlinear optics, their use in photonic integrated circuits and the applications of this technology for telecommunication, spectroscopy and metrology.
Explores the project MIXL, highlighting the importance of ultrafast semiconductor lasers for observing fast dynamics and enabling fast communication in nanotechnology.
Suspended epitaxial gallium nitride (GaN) on silicon (Si) photonic crystal devices suffer from large residual tensile strain, especially for long waveguides, because fine structures tend to crack due to large stress. By introducing spring-like tethers, des ...
Bristol2024
Since the discovery of dissipative Kerr solitons in optical microresonators, significant progress has been made in the understanding of the underlying physical principles from the fundamental side and generation of broadband coherent optical Kerr frequency ...
2D van der Waals heterojunctions (vdWH) have emerged as an attractive platform for the realization of optoelectronic synaptic devices, which are critical for energy-efficient computing systems. Photogating induced by charge traps at the interfaces indeed r ...