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Controlling Light with LightOn-chip
Nanophotonic Structures |
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Si Nanophotonics:
There have been several advances in the field of integrated photonics in the last few years with most of them directed towards the telecom industry at 1.5 µm. Devices including filters, modulators and routers are fabricated using a variety of materials like LiNb, GaAs and InP. These specific materials are used because of their excellent electro-optic properties and emissive capabilities. For pure telecom applications, where the optical components are usually discrete, these materials are excellent candidates.
Recently, there have been alternative emerging applications for photonics, where the demand for greater bandwidth requires the advantages provided by optics for interconnections. The most likely insertion points for integrated photonics into systems will be in places where an extreme amount of data is required to travel in a very small space. Two examples of applications are for microprocessor data busses (i.e. from microprocessor to memory or between multiple processors) and in the backplane of server racks. These applications involve an increase in complexity in the optical domain that requires greater integration of optical and electronic components. Monolithic integration of a suite of optical and electronic capabilities on one substrate is the natural progression for the vision of an integrated photonic system.
Using Si for optical interconnects would enable a platform for such a monolithic integration of optics and microelectronics. Photonics on silicon has been suggested since the 1970’s. It is only in the last few years, however, with the advancement of fabrication techniques that sub-micron-size photonic structures have been realized. This together with recent demonstrations of efficient fiber to waveguide couplers enabled the demonstration of a large number of ultra-compact photonic components with very low loss.
The challenges of using silicon as
a photonic material are its high propagation losses, low electro-optic
coefficient and low light emission efficiency, and the difficulty in
fiber-to-waveguide coupling. The high confinement nature of the recently
demonstrated photonic structures enabled some of the traditional limitations of
Si photonics to be overcome.
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(c) 2004 |
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Updated 10/19/2004 |