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US 7,454,143 B1Granted
Reconfigurable thin film based DWDM devices for reconfigurable add-drop optical systems
AssigneeAvanex Corporation
InventorsXuehua Wu, Mingjun Zhao, John Feng, Giovanni Barbarossa
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Abstract
A reconfigurable thin film based dense wavelength division multiplexing (DWDM) device is described for hitless switching of wavelengths by employing a reconfigurable filtering device. The reconfigurable filtering device is based on a mechanical switching of a filtering chip which has a thin film coated a first one-half of a first face for interference wavelength filtering and has a gold-mirror coated on a second one-half of the first face for high reflection.
Claims19
A reconfigurable thin-film-based dense wavelength division multiplexing (DWDM) device, comprising:
- a dual fiber collimator having an input port for receiving an input optical signal and a reflection output port;
- a single fiber collimator having a transmission output port;
- and
- a thin film filter located between the dual fiber collimator and the single fiber collimator, the thin film filter having a first face and a second face, the first face of the thin film filter having an upper one-half and a lower one-half, the upper one-half of the first face of the thin film having a thin film coating that allows a specific wavelength of the input optical signal to pass through and the lower one-half of the first face in the thin film filter being coated with a reflective material that reflects the input optical signal, wherein the reflective coating has a thickness that is an integer multiple of the specific wavelength of the input optical signal, divided by sin(θ), wherein the angle θ is equal to an incident angle between the input optical signal and the thin film filter, and wherein the thin film filter is movable between a pass-through state, a transient state and a blocking state along a single axis, whereby in the transient state a portion of the optical signal projects on the thin film coating and another portion of the optical signal projects on the reflective material.
1 more element
A reconfigurable device, comprising:
- an input port for receiving a light signal;
- and
- a thin film filter having a first face and a second face, the first face of the thin film filter having an upper surface area and a lower surface area, wherein the upper surface area is thin film coated for passing through a wavelength of the light signal and the lower surface area is coated with a reflective material for blocking and reflecting the light signal, wherein the coating of the reflective material has a thickness t that allows for hitless switching as the thin film filter moves between a pass-through state and a blocking state, wherein the thickness t is equal to a parameter n times a specific wavelength λ of the light signal, divided by sin(θ), wherein the angle θ is equal to an incident angle between the light signal and the thin film filter, and wherein the parameter n is an integer.
A hitless thin film filter;
- comprising:
- a thin film filter having a first face and a second face, the first face having an upper surface and a lower surface;
- and
- a reflective material coated onto the lower surface of the first face in the thin film filter, wherein the reflective material has a thickness t in which the thickness t affects the intensity of a light beam I that is projected from a cross junction of the thin film filter, the cross junction of the thin film filter being located between the upper surface and the lower surface, wherein the thickness t is selected so that the intensity of the light beam I that is projected from the cross junction of the thin film filter is at a maximum and wherein the thin film filter is movable between a pass-through state, a transient state and a blocking state along a single axis such that the light beam projects on the upper surface and on the lower surface when the thin film filter is in the transient state, wherein the thickness t is governed by the following equation:
- t(sin θ)=nλ, wherein the angel θ denotes the incident angle of light, the symbol λ denotes a particular wavelength and the symbol n denotes an integer.
2 more elements
A reconfigurable add-drop optical system, comprising:
- a first thin film filter chip having a first face and a second face, wherein the first face of the first thin film filter chip is partially coated with a thin film to transmit a specific wavelength of a light signal and is partially coated with a reflective material to a thickness t that allows the specific wavelength of the light signal to undergo hitless switching as a portion of a light beam projects on the thin film and another portion of the light beam projects on the reflective material, wherein the thickness t=nλ/(sin θ) and wherein n=an integer, λ=a specific wavelength, and the angle θ=the angle θ is an incident angle between the light signal and the first face having the thin film;
- and
- a second thin film chip, coupled to the first thin film chip, having a first face and a second face, wherein the first face of the second thin film filter chip is partially coated with a thin film and partially coated with a reflective material.
Dependencies are inferred from the claim text.