Other

Itf Optical Technologies Inc.

Nicolas Godbout

Alain Villeneuve

Fran&ccedil;ois Gonthier

Nelson Vachon

Bruno Y Dion

Felix Bussieres

Suzanne Lacroix

Francois Seguin

A multi-user quantum cryptography system and method are described herein. The system comprises a relay including a quantum information server so configured as to generate quantum information communications having different wavelengths and a multiplexer so configured as to separate the different quantum information communications generated by the quantum information server by their wavelength and to supply each communication to a respective user.

Multi-user quantum cryptography method and system using wavelength division multiplexing

The invention provides an all-fiber Mach-Zehnder interferometer in which the composition of one of the arms, which connect the couplers, or of a segment of such arm, is doped with dopants, such as GeO, PO, BOand F. The doping is adjusted to obtain a desired thermal dependence of the interferometer within a given temperature range. The segments can further be tapered with an adiabatic taper.

Passive thermal compensation of all-fiber Mach-Zehnder interferometer

A Mach-Zehnder device including an input port, an output port, a substantially achromatic first coupling region optically connected to the input port and a substantially achromatic second coupling region optically connected to the output port. An intermediate region is optically connected to the first and second coupling regions. The intermediate region includes a first intermediate branch and a second intermediate branch. The first intermediate branch defines a phase shifting portion. The phase shifting portion, in turn, defines a phase shifting portion level of birefringence over the length of the phase shifting portion. The phase shifting portion level of birefringence is different that the level of birefringence prevailing over the remainder of the first intermediate branch. The birefringence differential between the phase shifting portion level of birefringence and the level of birefringence prevailing over the remainder of the first intermediate branch creates a polarization selective phase shift enabling the generally wavelength insensitive device to be used either as a coupler or splitter.

Optical phase shifting, splitting and combining device

An all-fiber optical depolarizer is provided in which polarized light is controllably injected into a polarization beam splitter at a 45&deg; angle. The beam splitter is combined with a loop made of standard non-birefringent fiber through which one of the polarizations split by the beam splitter circulates. The loop has a length greater than the coherence length of the light source. The interaction of the beam splitter and the loop produces incoherent depolarized light at the output transmission port of the beam splitter.

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Montreal, Canada

Nicolas Godbout