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ABSTRACT:
Nanotechnology is a key for innovation in biology and material science. New motors move material samples or instruments with a step size of the atom diameter.TinyGrippers and other tools work precisely on micro and nanostructures. The world of the small things is formed which has revolutionized the world. Nanotechnology offers tools for applications in various areas such as medicine, nanotechnology, military, machinery and many other spheres of life. These include micromanipulators, grippers , AFM, STM, Assemblers and still more which are being designed everyday. By the end of this sentence, may be millions of Nan tools be created . These tools are of nanosize (as small as our hair tip) and can perform even the tiniest operation in places which are inaccessible to human-beings.
In this paper we have discussed how Lead Selenide nanocrystals can be easily incorporated into thin film or planar optical devices for ultrafast switching, all-optical processing, and wavelength conversion that will be extremely useful for the implementation of next generation optical communication systems.
INTRODUCTION:
We live in the information age where computing and data transport is based upon aging silicon technology. Scientists are starting to unlock the fundamental secrets of our DNA, requiring unprecedented amounts of computer processing to make sense of the abundance of information. Collaborators no longer need to work at the same facility but can be separated by miles with the Internet. The public now demands increased data flow to their homes including such broadband applications as digital cable, video-on-demand services and real-time video phoning. With this explosion of information, comes an increased need to share data and transport information from across the room or across the country. Hence, there is a continuing need to increase the speed of computing and for ultra-fast, all-optical switching (i.e. switching light with light) for both the telecommunication and computer industries.
OPTICAL SWITCHING TECHNOLOGY- A REPLACEMENT
FOR TRADITIONAL TECHNOLOGY:
Through advanced lithography techniques it is now possible to fit 300 million transistors on a single processor chip. Moore’s Law still holds that the number of transistors per chip doubles every 18 months. As these densities increase, problems are introduced such as dielectric breakdown, hot carriers and short channel effects, all contributing to device reliability problems. All-optical switching presents a fundamentally different solution to these issues and problems. By using photons traveling through fiber and all-optical switching, interference problems are reduced. In addition, photonic circuits are more cost effective at higher speeds and have no cross-talk between electrical signal components
1. EVIDOTS:
The ideal material system for optical switching would make use of currently
available fabrication methods and have extremely high nonlinear optical properties. The ideal nonlinear materials for optical switching are those, which interact with light strongly and can therefore be used to switch light with light. An optical switching component requires efficient nonlinear materials for its operation. A restraining factor on building optical switches and transistors is the inefficiency of currently available optical materials and the high power requirements to switch these materials. semiconductor nanocrystals (EviDots) are extremely fast nonlinear optical
material that can be used to build switching components that are many orders of magnitude faster than other semiconductor technologies. Additionally, they exhibit sub-picosecond switching speeds, are extremely nonlinear, and can be tuned to specific wavelengths through band gap engineering
Evident is producing Lead Selenide (PbSe) nanocrystals that can be engineered to have extremely strong and fast nonlinear optical responses at the relevant 1310nm or 1550nm wavelength ranges or additional wavelengths if required. The nanocrystals can be implemented directly into an optical fiber or into a thin film using a polymer or glass matrix. These devices can then be used to implement advanced optical telecommunication capabilities such as all-optical packet switched routing, optical time division multiplexing, 3-R regeneration, etc.