Highly linear electro-optic delay generator for all-optical pulse-position modulation
First Claim
1. An optical delay generator comprising:
- a first optical waveguide comprising electro-optically active material, said first waveguide having a longitudinal axis, wherein optical signals propagate within said waveguide in a direction substantially parallel to said longitudinal axis;
a chirped distributed Bragg reflector structure formed within said first waveguide, said chirped distributed Bragg reflector structure having a direction of propagation substantially parallel to said longitudinal axis and reflecting optical signals in a direction substantially opposite to said direction of propagation;
a first elongate electrode disposed adjacent a first side of said first optical waveguide;
a second elongate electrode disposed adjacent a second side of said first optical waveguide, wherein a voltage applied between said first electrode and said second electrode generates an electric field across said chirped distributed Bragg reflector structure, said electric field having a direction normal to said direction of propagation; and
a second optical waveguide disposed adjacent to and substantially parallel to said first optical waveguide, said second optical waveguide being resonantly coupled to said first optical waveguide to receive optical signals reflected by said chirped distributed Bragg reflector structure.
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Accused Products
Abstract
An optical delay generator comprises a first waveguide made from electro-optically active material resonantly coupled to a second non-electro-optically active waveguide. The first waveguide contains a chirped distributed Bragg reflector structure which reflects optical signals at a specific wavelength at a specific reflection point within the structure. An electric field applied to the first waveguide changes the refractive index of the electro-optically active material and thus shifts the reflection point. Optical signals reflecting from the reflection point are resonantly coupled into the second waveguide, and are thus not affected by the electric field applied to the first waveguide. The controllable optical delay applied to the optical signals results from control over the reflection point and the round-trip travel time for an optical signal forward propagating in the first waveguide, being reflected at the reflection point, and backward propagating in the second waveguide.
3 Citations
29 Claims
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1. An optical delay generator comprising:
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a first optical waveguide comprising electro-optically active material, said first waveguide having a longitudinal axis, wherein optical signals propagate within said waveguide in a direction substantially parallel to said longitudinal axis;
a chirped distributed Bragg reflector structure formed within said first waveguide, said chirped distributed Bragg reflector structure having a direction of propagation substantially parallel to said longitudinal axis and reflecting optical signals in a direction substantially opposite to said direction of propagation;
a first elongate electrode disposed adjacent a first side of said first optical waveguide;
a second elongate electrode disposed adjacent a second side of said first optical waveguide, wherein a voltage applied between said first electrode and said second electrode generates an electric field across said chirped distributed Bragg reflector structure, said electric field having a direction normal to said direction of propagation; and
a second optical waveguide disposed adjacent to and substantially parallel to said first optical waveguide, said second optical waveguide being resonantly coupled to said first optical waveguide to receive optical signals reflected by said chirped distributed Bragg reflector structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for delaying optical signals, said method comprising the steps of:
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coupling optical signals into a first waveguide comprising electro-optically active material, said first waveguide having a chirped distributed Bragg reflector structure formed within said electro-optically active material, said chirped distributed Bragg reflector structure reflecting said optical signals at a reflection point having a position within said structure to provide reflected optical signals;
applying an electric field across said first waveguide to change an index of refraction of said electro-optically active material so as to change the position of said reflection point;
coupling said reflected optical signals into a second waveguide, said second waveguide resonantly coupled to said first waveguide; and
,directing said reflected optical signals out of said second waveguide to provide delayed optical signals. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. An optical delay generator comprising:
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a waveguide layer comprising;
a first optical waveguide comprising electro-optically active material, said first waveguide having a longitudinal axis, wherein optical signals propagate within said waveguide in a direction substantially parallel to said longitudinal axis;
a chirped distributed Bragg reflector structure formed within said first waveguide, said chirped distributed Bragg reflector structure having a direction of propagation substantially parallel to said longitudinal axis and reflecting optical signals in a direction substantially opposite to said direction of propagation; and
a second optical waveguide disposed adjacent to and substantially parallel to said first optical waveguide, said second optical waveguide resonantly coupled to said first optical waveguide to receive optical signals reflected by said chirped distributed Bragg reflector structure;
an insulating layer disposed above said waveguide layer;
a ground electrode disposed on said insulating layer and positioned above said second optical waveguide; and
a signal electrode disposed on said insulating layer and positioned such that the first waveguide is located between and below said ground electrode and said signal electrode, said signal electrode being electrically isolated from said ground electrode. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29)
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Specification