California Institute of Technology

Ondax, Inc.

Joerg Hukriede

Demetri Psaltis

Christophe Moser

Karsten Buse

Greg Steckman

Ingo Nee

Joseph W Goodman

The present invention provides a multi-channel tunable filter and methods for making such a filter. In one embodiment, the filter comprises a bank of gratings or a continuously varying filter frequency imprinted into a filter material, such as Lithium Niobate or glass or polymer. An optical read-head comprising a pair of lenses is configured to pass light from within an optical fiber carrying multiple wavelengths through an appropriate grating to extract or drop a specific wavelength. To ensure continuous data transmission, the filter is tuned to a wavelength by configuring the read-head to move in a hitless manner. In one embodiment, the gratings are recorded by the interference of two beams. A first plane wave reflects off a first mirror stack and a second plane wave reflects off a second mirror stack. In another embodiment, the gratings are recorded by a phase masking method.

Method and apparatus for implementing a multi-channel tunable filter

The present invention provides a multi-channel tunable filter and methods for making such a filter. In one embodiment, the filter comprises a bank of gratings imprinted into a filter material, such as Lithium Niobate. In another embodiment, the filter comprises a bank of gratings imprinted on a thin-film filter. An optical read-head comprising a pair of lenses is configured to pass light from within an optical fiber carrying multiple wavelengths through an appropriate grating to extract or drop a specific wavelength. To ensure continuous data transmission, the filter is tuned to a wavelength by configuring the read-head to move in a hitless manner. In one embodiment, the gratings are recorded by the interference of two beams. A first plane wave reflects off a first mirror stack and a second plane wave reflects off a second mirror stack. In another embodiment, the gratings are recorded by a phase masking method.

The present invention is a method and apparatus for a rotating, tunable, holographic drop filter connected to a fiber optic source. The filter uses a quasi phase-conjugate optical system for a drop-channel fiber coupling and WDM channels which are introduced to the system. The light from these channels is collimated and passed through a volume phase holographic material so that only one WDM channel is diffracted and the rest pass through the holographic material unaffected. A quasi phase-conjugate diffracted beam is generated by the optical system to reflect the diffracted channel back towards the holographic material. The reflected light is Bragg matched to the holographic material so that it is re-diffracted along a path identical to the original incident light beam. A free-space circulator may be used to direct the diffracted beam to a fiber optic collimator, which is different from the fiber optic collimator of the incident light beam.

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Lengerich, Germany

Joerg Hukriede