Integrated optical components with wavelength tuning and power isolation functions
AssigneeDicon Fiberoptics, Inc.
InventorHo-Shang Lee
Life of this patent
Estimating the term…
Abstract
A tunable optical filter integrates the functions of wavelength tuning and power isolation of back reflection. The optical signal enters a Faraday rotator twice, and isolation is provided by two birefringent crystals, having their optical axes oriented at 45 degrees with respect to each other. The two birefringent crystals are on the same side of the Faraday rotator. The integration of an optical tunable filter and an isolator function into a single packaged component helps to reduce the size and complexity of optical amplifier systems, such as EDFAs and PDFAs, operating in the 1550 nm and 1310 nm transmission bands, respectively.
Claims21
A tunable optical filter device, comprising:
- a diffraction element oriented to differentially diffract light of different wavelengths of a beam of light incident thereupon from an input port;
- a reflector configured to reflect a portion of the beam of light incident thereupon by the diffraction element to be diffracted a second time by the diffraction element in an optical path between the input port and an output port;
- a first birefringent element having a first optical axis in the optical path between the input port and the diffraction element;
- a second birefringent element having a second optical axis in the optical path between the diffraction element and the output port, wherein the second optical axis is oriented substantially at a 45 degree angle with respect to the first optical axis along the optical path;
- one or more Faraday rotators located in the optical path between the first and second birefringent elements such that the optical path passes through each of the Faraday rotators one or more times, where the one or more Faraday rotators are configured to provide a combined rotation of polarization to a beam of light traversing the optical path between the first and second birefringent elements substantially equal to the difference in orientation between the optical axes of the first and second birefringent elements;
- and
- an actuator connected to change a position of the reflector so that a selected range of wavelengths of the portion of the beam of light incident upon the reflector is reflected along the optical path from the input port to the output port.
A method, comprising:
- receiving a beam of light from an input port;
- refracting the beam of light a first time by a first birefringent element having a first optical axis;
- differentially diffracting, by a diffraction element, light of different wavelengths of the beam of light from the input port that is incident thereon through the first birefringent element;
- positioning a reflector so that a first selected range of wavelengths of a portion of the beam of light incident upon the reflector from the diffraction element is reflected along an optical path from the input port to an output port;
- diffracting a second time by the diffraction element of the portion of the beam of light incident upon the reflector along a portion the optical path between the reflector and the output port;
- refracting the beam of light a second time along a portion the optical path between the diffraction element and the output port by a second birefringent element having a second optical axis, wherein the second optical axis is oriented substantially at a 45 degree angle with respect to the first optical axis along the optical path;
- and
- rotating one or more times a polarization of a beam of light traversing the optical path between the first and second birefringent elements, wherein the combined rotation from the one or more times is substantially equal to the difference in orientation between the optical axes of the first and second birefringent elements.
Dependencies are inferred from the claim text.