Wavelength selective optical switch
First Claim
1. A wavelength dependent switch, comprising in sequence:
- a polarization beam splitter having at least a first input port, for receiving at least one input beam having at least two wavelength components, said polarization beam splitter being operative to spatially split each of said at least one input beam into a pair of beams of separate polarization components,a first dispersive element receiving said pair of beams of separate polarization components, and operative to spatially disperse said wavelength components of each of said pair of beams of separate polarization components in a dispersion plane disposed at an angle to the plane in which said polarization components are split;
a first focusing element receiving said wavelength components of each of said pair of beams of separate polarization components from said first dispersion element, without any intervening polarization manipulation element;
a polarization modulating element disposed in the focal region of said first focusing element, without any intervening polarization dependent deflection element between said first focusing element and said polarization modulating element, said polarization modulating element being pixelated generally along the direction of the dispersion such that each pixel is associated with a separate wavelength component, each pixel of said polarization modulating element being operative to change the state of the polarization of light passing through said pixel according to a control signal applied to said pixel;
a second focusing element receiving said light after passing through said polarization modulating element;
a second dispersive element receiving light from said second focusing element, and operative to combine said separate wavelength components of each of said pair of beams into multi-wavelength beams; and
a polarization beam combiner having two output ports, said polarization beam combiner receiving each of said pair of multi-wavelength beams, and operative to combine said separate polarization components such that each wavelength component of said at least one input beam is directed to one of said two output ports according to the control signal applied to said pixel associated with said wavelength.
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Accused Products
Abstract
A wavelength selective switch, in which an input optical signal is wavelength-dispersed and polarization-split in two angularly oriented planes. A polarization rotation device, such as a liquid crystal polarization modulator, pixelated along the wave-length dispersive direction such that each pixel operates on a separate wavelength channel, rotates the polarization of the light signal passing through the pixel, according to the control voltage applied to that pixel. The polarization modulated signals are then wave-length-recombined and polarization-recombined by means of similar dispersion and polarization combining components as were used to respectively disperse and split the input signals. The direction of the output signal is determined by whether the polarization of a particular wavelength channel was rotated by the polarization modulator pixel, or not. In this way, a fast, wavelength dependent, optical switch is provided, capable of use in WDM switching applications.
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Citations
29 Claims
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1. A wavelength dependent switch, comprising in sequence:
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a polarization beam splitter having at least a first input port, for receiving at least one input beam having at least two wavelength components, said polarization beam splitter being operative to spatially split each of said at least one input beam into a pair of beams of separate polarization components, a first dispersive element receiving said pair of beams of separate polarization components, and operative to spatially disperse said wavelength components of each of said pair of beams of separate polarization components in a dispersion plane disposed at an angle to the plane in which said polarization components are split; a first focusing element receiving said wavelength components of each of said pair of beams of separate polarization components from said first dispersion element, without any intervening polarization manipulation element; a polarization modulating element disposed in the focal region of said first focusing element, without any intervening polarization dependent deflection element between said first focusing element and said polarization modulating element, said polarization modulating element being pixelated generally along the direction of the dispersion such that each pixel is associated with a separate wavelength component, each pixel of said polarization modulating element being operative to change the state of the polarization of light passing through said pixel according to a control signal applied to said pixel; a second focusing element receiving said light after passing through said polarization modulating element; a second dispersive element receiving light from said second focusing element, and operative to combine said separate wavelength components of each of said pair of beams into multi-wavelength beams; and a polarization beam combiner having two output ports, said polarization beam combiner receiving each of said pair of multi-wavelength beams, and operative to combine said separate polarization components such that each wavelength component of said at least one input beam is directed to one of said two output ports according to the control signal applied to said pixel associated with said wavelength. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A wavelength dependent switch, comprising in sequence:
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a polarization beam splitter having a first and second port, at least one of said ports receiving an input beam comprising at least two wavelength components, said polarization beam splitter being operative to spatially split each of said at least one input beam into a pair of beams of separate polarization components; a dispersive element receiving said pair of beams of separate polarization components, and operative to spatially disperse said wavelength components of each of said pair of beams of separate polarization components in a dispersion plane disposed at an angle to the plane in which said polarization components are split; a focusing element receiving said wavelength components of each of said pair of beams of separate polarization components from said dispersion element, without any intervening polarization manipulation element; a polarization modulating element disposed in the focal region of said focusing element without any intervening polarization dependent deflection element between said focusing element and said polarization modulating element, said polarization modulating element being pixelated generally along the direction of the dispersion such that each pixel is associated with a separate wavelength component, each pixel of said polarization modulating element being operative to change the state of the polarization of light passing through said pixel according to a control signal applied to said pixel; and a reflecting surface operative to reflect said light back in sequence through said pixelated polarization modulating element, said focusing element, said dispersive element and said polarization beam splitter, such that each wavelength component of said light is output to one of said first and second ports according to the control signal applied to said pixel associated with said wavelength. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A wavelength dependent switch, comprising in sequence:
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a polarization beam splitter having at least a first input port, for receiving at least one input beam having at least two wavelength components, and operative to spatially split each of said at least one input beam into a pair of beams of separate polarization components, a first dispersive element receiving said pair of beams of separate polarization components, and operative to spatially disperse said wavelength components of each of said pair of beams of separate polarization components in a dispersion plane disposed at an angle to the plane in which said polarization components are split; a first focusing element receiving said wavelength components of each of said pair of beams of separate polarization components; a polarization modulating element disposed in the focal region of said first focusing element, said polarization modulating element being pixelated generally along the direction of the dispersion such that each pixel is associated with a separate wavelength component, each pixel of said polarization modulating element being operative to change the state of the polarization of light passing through said pixel according to a control signal applied to said pixel; a second focusing element receiving said light after passing through said polarization modulating element; a second dispersive element receiving light from said second focusing element, and operative to combine said separate wavelength components of each of said pair of beams into multi-wavelength beams; and a polarization beam combiner having two output ports, said polarization beam combiner receiving each of said pair of multi-wavelength beams, and operative to combine said separate polarization components such that each wavelength component of said at least one input beam is directed to one of said two output ports according to the control signal applied to said pixel associated with said wavelength; wherein said separate polarization components directed to a first one of said two output ports traverse essentially the same optical paths into said polarization beam combiner as those of said separate polarization components directed to a second one of said output ports. - View Dependent Claims (27)
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28. A wavelength dependent switch, comprising in sequence:
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a polarization beam splitter having a first and second port, at least one of said ports receiving an input beam comprising at least two wavelength components, and operative to spatially split each of said at least one input beam into a pair of beams of separate polarization components; a dispersive element receiving said pair of beams of separate polarization components, and operative to spatially disperse said wavelength components of each of said pair of beams of separate polarization components in a dispersion plane disposed at an angle to the plane in which said polarization components are split; a focusing element receiving said wavelength components of each of said pair of beams of separate polarization components; a polarization modulating element disposed in the focal region of said focusing element, said polarization modulating element being pixelated generally along the direction of the dispersion such that each pixel is associated with a separate wavelength component, each pixel of said polarization modulating element being operative to change the state of the polarization of light passing through said pixel according to a control signal applied to said pixel; and a reflecting surface operative to reflect said light back in sequence through said pixelated polarization modulating element, said focusing element, said dispersive element and said polarization beam splitter, such that each wavelength component of said light is output to one of said first and second ports according to the control signal applied to said pixel associated with said wavelength; wherein said spatially split polarization components of said input beams from said first input port traverse essentially the same optical paths on exiting said polarization beam splitter as those of said spatially split polarization components of said input beams from said second input port.
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29. A wavelength dependent switch, comprising in sequence:
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a polarization beam splitter having a first and second port, at least one of said ports receiving an input beam comprising at least two wavelength components, said polarization beam splitter being operative to spatially split each of said at least one input beam into a pair of beams of separate polarization components; a dispersive element receiving said pair of beams of separate polarization components, and operative to spatially disperse said wavelength components of each of said pair of beams of separate polarization components in a dispersion plane disposed at an angle to the plane in which said polarization components are split; a focusing element receiving said wavelength components of each of said pair of beams of separate polarization components from said first dispersion element; a polarization modulating element disposed in the focal region of said focusing element without any intervening polarization dependent deflection element between said focusing element and said polarization modulating element, said polarization modulating element being pixelated generally along the direction of the dispersion such that each pixel is associated with a separate wavelength component, each pixel of said polarization modulating element being operative to change the state of the polarization of light passing through said pixel according to a control signal applied to said pixel; and a reflecting surface operative to reflect said light back in sequence through said pixelated polarization modulating element, said focusing element, said dispersive element and said polarization beam splitter, such that each wavelength component of said light is output to one of said first and second ports according to the control signal applied to said pixel associated with said wavelength, wherein said spatially split polarization components of said input beam from said first input port traverse essentially the same optical paths within said switch after exiting said polarization beam splitter as those of said spatially split polarization components of said input beam from said second input port.
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Specification