Method and apparatus for detecting multiple optical wave lengths
AssigneeBrown University Research Foundation
InventorsDaniel Levner, Martin F. Fay, Jingming Xu
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Abstract
Optical gratings that perform a number of functions at various wavelengths are formed by various methods that preserve spectral information within a wavelength band, the functions including: coupling radiation from one waveguide to another, controllable gratings that operate on different wavelengths in response to external control signals.
Claims25
An optical device comprising at least two waveguides in at least one propagation layer of grating material, a first one of said waveguides adapted for transporting input radiation from a first input port to output radiation exiting from a first output port and a second one of said waveguides transporting input radiation from a second input port to output radiation exiting from a second output port, and a one- or two-dimensional (binary) supergrating in a modulation layer of grating material for coupling input radiation propagating from one of said first and second input ports along a corresponding waveguide to the other of said first and second waveguides;
- and
- wherein said one- or two-dimensional supergrating comprises an array of discrete pixels and an array of controllable means each coupled to one of the discrete pixels, the controllable means being responsive to a set of control signals, for altering the modal index of refraction value in corresponding discrete pixels in said array in at least two modes.
An optical device comprising at least two waveguides in at least one propagation layer of grating material, a first one of said waveguides adapted for transporting input radiation from a first input port to output radiation exiting from a first output port and a second one of said waveguides transporting input radiation from a second input port to output radiation exiting from a second output port, and a one- or two-dimensional (binary) supergrating in a modulation layer of grating material for coupling input radiation propagating from one of said first and second input ports along a corresponding waveguide to the other of said first and second waveguides;
- and
- wherein said first and second waveguides are symmetric and said one- or two-dimensional supergrating comprises a central portion between said first and second waveguides having a first pattern of high and low values of index of refraction and first and second outer portions having a second pattern of high and low values of index of refraction having the opposite sense to said first pattern, whereby said one- or two-dimensional supergrating suppresses back reflection in said first and second waveguides.
A device for processing optical radiation in a set of wavelengths comprising a set of waveguides, each waveguide having at least one input port and at least one output port, in which an input beam of radiation traveling on an input waveguide of the set of waveguides passes through at least one wavelength dependent supergrating coupler that couples a selected wavelength band in or out of the input waveguide, so that the remaining optical beam in the input waveguide has a wavelength range that has been added to or subtracted from by the selected wavelength band;
- and
- wherein said wavelength dependent supergrating coupler comprises an array of discrete pixels and an array of controllable means each coupled to one of the discrete pixels, the controllable means being responsive to a set of control signals, for altering the modal index of refraction value in corresponding discrete pixels in said array in at least two modes.
An optical device comprising an input port for receiving incident radiation and directing the radiation on an array of pixels comprising a supergrating, each pixel having a modal index of refraction selected from a set of index values, the array of pixels collectively processing the incident radiation and directing at least one beam of output radiation to at least one output port, in which at least some of the array of pixels are connected to control means for controllably setting the value of the modal index of refraction of the corresponding pixels in response to a control signal, so that the process applied to the incident radiation may be determined by the control signals applied to the control means.
An optical device comprising:
- first and second optical wave transmitting means;
- a means for coupling optical signals between the first and second optical wave transmitting means;
- a one- or two-dimensional array of pixels disposed on the coupling means, the pixels each comprising a means for altering a modal index of refraction value in at least two modes in discrete locations on said coupling means;
- and
- a means for controlling the modal index of refraction altering means to effect a one- or two-dimensional (binary) wavelength dependent supergrating in the coupling layer.
A method for controlling optical radiation comprising:
- applying a pattern of control signals to discrete pixels in a one- or two-dimensional array of discrete modal index altering means to effect a supergrating on a modulation layer disposed on first and second waveguides;
- inputting radiation into the first waveguide;
- and
- coupling a portion of the input radiation through the modulation layer to the second waveguide, the coupled portion corresponding to a wavelength corresponding to the pattern of control signals.
Dependencies are inferred from the claim text.