Non-moving parts add/drop device
AssigneeJDS Uniphase Corporation
InventorsHongwei Mao, Kok Wai Chang, Yi-Xin Chen
Life of this patent
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Abstract
The instant invention provides an add/drop device including a wavelength filter, a quarter waveplate disposed on either side of the wavelength filter, and a polarizing beamsplitter disposed on either side of the quarter waveplates. Each polarizing beamsplitter has an input port and an output port for launching and receiving a beam of light having a known polarization. A polarization switch is optically coupled to each input/output port for selectably rotating the polarization of the input/output beams of light. Advantageously, the polarization switches, which work in cooperation with each other and the polarizing beam splitters, provide means for a non-moving parts add/drop device.
Claims21
An add/drop device comprising:
- first and second optically coupled polarising beamsplitters;
- a wavelength filter disposed between the first and second polarising beamsplitters;
- first and second polarisation rotators disposed between the filter and the first polarising beamsplitter and the filter and the second polarising beamsplitter, respectively;
- first and second input ports optically coupled to the first and second polarising beamsplitters, respectively, each of the first and second input ports for launching a beam of light having a predetermined polarisation;
- first and second output ports optically coupled to the first and second polarising beamsplitters, respectively;
- and
- first and second polarisation switches optically coupled to the first input port and one of the first and second output ports, respectively, each of the first and second switches for selectably rotating the polarisation of a beam of light launched therethrough and configured to work in cooperation with the other.
An add/drop multiplexer comprising:
- a first and a second polarising beamsplitter;
- a wavelength filter disposed between the first and second polarising beamsplitters;
- a polarisation rotator disposed between each polarising beamsplitter and the filter;
- an input port for launching a multiplexed beam of light having a predetermined polarisation into the first polarising beamsplitter;
- a first polarisation switch disposed between the input port and the first polarising beamsplitter for selectably rotating the polarisation of the multiplexed beam of light, the first polarisation switch operable in a first mode of operation wherein the polarisation is switched such that the first polarising beamsplitter directs the multiplexed beam of light away from the filter to an output port optically coupled to one of the first and second polarising beamsplitters, and a second mode of operation wherein the polarisation is switched such that the first polarising beamsplitter directs the multiplexed beam of light towards the filter where a portion of the beam of light is directed to a drop port optically coupled to the other of the first and second polarising beamsplitters and a remaining portion is directed to the output port;
- an add port for launching an add beam of light having a predetermined polarisation into the second polarising beamsplitter such that it is directed to the output port having a same polarisation as the remaining portion;
- and,
- a second polarisation switch optically coupled to the output port for working in cooperation with the first polarisation switch to selectably rotate the polarisation of one of the multiplexed beam of light and a composite beam of light including the remaining portion and the add beam of light.
In a four-port add/drop optical system comprising an input port and an output port for transmitting and receiving a multiplexed beam of light, respectively, an add port and a drop port for transmitting an added and dropped beam of light, respectively, a first and a second polarising beamsplitter, a wavelength filter disposed between the first and second polarising beamsplitters, a polarisation rotator disposed between each polarising beamsplitter and the wavelength filter, and a first and a second polarisation switch optically coupled to the input port and the output port, respectively, a method comprising the steps of:
- launching a first beam of light having a known polarisation from the input port to the first polarising beamsplitter;
- operating the first polarisation switch in a first mode of operation such that the first polarising beamsplitter directs the first beam of light away from the wavelength filter to the output port;
- operating the first polarisation switch in a second mode of operation such that the first polarising beamsplitter directs the first beam of light to the wavelength filter, where a first portion is directed to the drop port and a second portion is directed to the output port;
- launching a second beam of light having a known polarisation from the add port to the second polarising beamsplitter;
- operating the second polarisation switch in one of the first and second modes of operation synchronously with the first polarisation switch.
Dependencies are inferred from the claim text.