LIQUID CRYSTAL OPTICAL DEVICE CONFIGURED TO REDUCE POLARIZATION DEPENDENT LOSS AND POLARIZATION MODE DISPERSION
First Claim
1. An optical device comprising:
- a birefringent displacer for dividing an input beam into a first component and a second component;
a liquid crystal (LC) structure for conditioning the polarization state of incident light and disposed in optical paths of the first and second components;
a half-wave plate disposed in the optical path of the first component between the birefringent displacer and the LC structure; and
a glass plate disposed in the optical path of the second component between the birefringent displacer and the LC structure.
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Accused Products
Abstract
An LC-based optical device compensates for differences in optical path lengths of polarization components of input beam. As a result, PDL and PMD of the optical device are reduced. The compensation mechanism may be a glass plate that is disposed in an optical path of a polarization component so that the optical path length of that polarization component can be made substantially equal to the optical path length of the other polarization component that traverses through a half-wave plate. Another compensation mechanism is a birefringent displacer that has two sections sandwiching a half-wave plate, wherein the two sections are of different widths and the planar front surface of the birefringent displacer can be positioned to be non-orthogonal with respect to the incident input light beam.
19 Citations
20 Claims
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1. An optical device comprising:
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a birefringent displacer for dividing an input beam into a first component and a second component; a liquid crystal (LC) structure for conditioning the polarization state of incident light and disposed in optical paths of the first and second components; a half-wave plate disposed in the optical path of the first component between the birefringent displacer and the LC structure; and a glass plate disposed in the optical path of the second component between the birefringent displacer and the LC structure. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An optical device comprising:
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a birefringent displacer for dividing an input beam into a first component and a second component, the birefringent displacer including a first birefringent crystal and a second birefringent crystal, the first and second birefringent crystals having different thicknesses; a liquid crystal structure (LC) for conditioning the polarization state of incident light and disposed in optical paths of the first and second components; and a half-wave plate disposed in the optical path of the first component between the birefringent displacer and the LC structure. - View Dependent Claims (8, 9, 10)
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11. A wavelength selective switch comprising:
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a wavelength dispersive element for separating an input beam into its wavelength components; a birefringent displacer disposed in optical paths of the wavelength components, the birefringent displacer including a first birefringent crystal and a second birefringent crystal, the first and second birefringent crystals having different thicknesses; a liquid crystal structure (LC) for conditioning the polarization state of incident light and disposed in optical paths of the wavelength components; and a half-wave plate disposed between the birefringent displacer and the LC structure. - View Dependent Claims (12, 13, 14, 15)
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16. A method for reducing the polarization dependent loss (PDL) of an input beam that passes through a liquid crystal optical device having a birefringent displacer, said method comprising:
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measuring the PDL of the input beam; rotating the birefringent displacer; and measuring the PDL of the input beam after rotation of the birefringent displacer. - View Dependent Claims (17, 18, 19, 20)
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Specification