Running intereference for fully functional opto
The device was developed by etching waveguides during post-processing of a standard electronic integrated circuit, achieving optoelectronic functionality with only one more mask and one additional process. The electronics enable a phase shift of light in one of the two arms of a Mach-Zehnder interferometer achieving on/off or modulation functions.
The researchers believe that the technology opens the way to direct optical switches, modulators or routers, without the need for optic/electronic signal conversion. The team is interested in transferring this technology to a company designing equipment in optical telecom or instrumentation. Patents have been applied for but not yet granted. The team is interested in transferring its know-how to a silicon manufacturer or a fabless design-house active in designing optical telecoms or instrumentation integrated circuits. Final development is needed to make the product suitable for the market (packaging and optimisation).
The technology is similar to work described by Intel scientists in Nature (February 12, 2004, reported Bulletin 517, February 13, 2004). Modulation of the refractive index in an SOI waveguide is achieved through heating (thermo-optic effect) or through charge injection (plasma dispersion effect). Both of these effects can be performed by electronics integrated on the same substrate. As a consequence, light propagating in such a waveguide is proportionally phase-shifted. This phase modulator is the basic active block for the fully functional optoelectronic circuits.
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