Managing optical nonlinearities and optical mode sorting
An apparatus comprises: a plurality of linear optical elements, where each linear optical element is configured to apply a change in amplitude or phase of an optical wave interacting with that linear optical element; and a plurality of nonlinear optical elements, where each nonlinear optical element is configured to apply a change in an amplitude or a phase of an optical wave interacting with that nonlinear optical element, where the change in an amplitude or a phase is a nonlinear function of an amplitude or a phase of the optical wave; wherein one or more nonlinear optical elements are arranged to interact with an optical wave between successive interactions of the optical wave with two linear optical elements; wherein the plurality of linear optical elements is configured to sort optical waves into one or more optical modes of a sorted mode distribution.
1 . An apparatus comprising:
an optical input configured to provide an input optical wave being characterized by a plurality of optical modes;
a mode sorter module configured to convert the plurality of optical modes of the input optical wave into a plurality of separated optical modes of a sorted mode distribution, where the separated optical modes are associated with a plurality of optical waves having different respective propagation axes; and
an optical circuit comprising
a plurality of input ports, where each input port of the plurality of input ports is configured to receive a respective mode of the plurality of optical modes of the sorted mode distribution,
a plurality of tunable linear optical modules, each tunable linear optical module of the plurality of tunable linear optical modules comprising one or more inputs and one or more outputs,
a plurality of nonlinear optical portions, where each nonlinear optical portion of the plurality of nonlinear optical portions is configured to provide a change in an amplitude or a phase of an optical wave propagating through that nonlinear optical portion of the plurality of nonlinear optical portions, and
a plurality of output ports;
wherein each output of each tunable linear optical module of the plurality of tunable linear optical modules is connected to an output port of the plurality of output ports or to an input of another tunable linear optical module of the plurality of tunable linear optical modules by a nonlinear optical portion of the plurality of nonlinear optical portions;
wherein each input port of the plurality of input ports is connected to an input of a tunable linear optical module of the plurality of tunable linear optical modules.
2 . The apparatus of claim 1 , wherein each tunable linear optical module of the plurality of tunable linear optical modules comprises a tunable interferometer module comprising at least two inputs and at least two outputs.
3 . The apparatus of claim 2 , wherein each tunable interferometer module comprises a first optical beamsplitter and a second optical beamsplitter, where the first optical beamsplitter is in optical communication with two inputs of the at least two inputs of that tunable interferometer module, the first optical beamsplitter is in optical communication with the second optical beamsplitter, and the second optical beamsplitter is in optical communication with two outputs of the at least two outputs of that tunable interferometer module.
4 . The apparatus of claim 3 , wherein each tunable interferometer module comprises a first phase shifter configured to apply a phase shift to an optical wave propagating through the first phase shifter and a second phase shifter configured to apply a phase shift to an optical wave propagating through the second phase shifter.
5 . The apparatus of claim 4 , wherein the first phase shifter is in optical communication with an input of the at least two inputs of that tunable interferometer module and the second phase shifter is in optical communication with each of the first optical beamsplitter and the second optical beamsplitter of that tunable interferometer module.
6 . The apparatus of claim 1 , wherein the change in an amplitude or a phase of an optical wave by each nonlinear optical portion of the plurality of nonlinear optical portions is a nonlinear function of an amplitude or a phase of the optical wave.
7 . The apparatus of claim 1 , wherein the optical circuit comprises optical circuitry on a photonic integrated circuit chip.
8 . The apparatus of claim 1 , wherein the optical input comprises an imaging system providing light from objects in a field-of-view.
9 . The apparatus of claim 8 , wherein the imaging system comprises a light source providing light to the objects in the field-of-view.
10 . The apparatus of claim 9 , wherein the light source comprises a coherent light source.
11 . A method comprising:
providing an input optical wave from an optical input, the input optical wave being characterized by a plurality of optical modes;
providing a mode sorter module configured to convert the plurality of optical modes of the input optical wave into a plurality of separated optical modes of a sorted mode distribution, where the separated optical modes are associated with a plurality of optical waves having different respective propagation axes;
arranging an optical circuit comprising
a plurality of input ports,
a plurality of tunable linear optical modules, each tunable linear optical module of the plurality of tunable linear optical modules comprising one or more inputs and one or more outputs,
a plurality of nonlinear optical portions, where each nonlinear optical portion of the plurality of nonlinear optical portions is configured to provide a change in an amplitude or a phase of an optical wave propagating through that nonlinear optical portion of the plurality of nonlinear optical portions, and
a plurality of output ports; and
coupling each optical mode of the plurality of optical modes of the sorted mode distribution into a respective input port of the plurality of input ports of the optical circuit;
wherein each output of each tunable linear optical module of the plurality of tunable linear optical modules is connected to an output port of the plurality of output ports or to an input of another tunable linear optical module of the plurality of tunable linear optical modules by a nonlinear optical portion of the plurality of nonlinear optical portions;
wherein each input port of the plurality of input ports is connected to an input of a tunable linear optical module of the plurality of tunable linear optical modules.
12 . The method of claim 11 , wherein the coupling comprises, for each optical mode of the plurality of optical modes, aligning an optical fiber to receive at least a portion of an optical wave associated with that mode of the plurality of optical modes, and aligning the optical fiber to provide the at least a portion of the optical wave associated with the mode of the plurality of optical modes to a respective input port of the plurality of input ports.
13 . An apparatus comprising:
a plurality of linear optical elements, where each linear optical element of the plurality of linear optical elements is configured to apply a change in amplitude or phase of an optical wave interacting with that linear optical element of the plurality of linear optical elements; and
a plurality of nonlinear optical elements, where each nonlinear optical element of the plurality of nonlinear optical elements is configured to apply a change in an amplitude or a phase of an optical wave interacting with that nonlinear optical element of the plurality of nonlinear optical elements, where the change in an amplitude or a phase is a nonlinear function of an amplitude or a phase of the optical wave;
wherein two or more nonlinear optical elements of the plurality of nonlinear optical elements are arranged to interact with an optical wave between successive interactions of the optical wave with two linear optical elements of different respective pairs of linear optical elements in the plurality of linear optical elements;
wherein the plurality of linear optical elements is configured to sort optical waves into one or more optical modes of a sorted mode distribution.
14 . The apparatus of claim 13 , wherein each linear optical element of the plurality of linear optical elements comprises a respective transmissive or reflective linear optical element.
15 . The apparatus of claim 13 , wherein each of the plurality of linear optical elements and the plurality of nonlinear optical elements are arranged over a respective plurality of planes, where each plane of the plurality of planes is substantially parallel to a common plane that is substantially perpendicular to a propagation direction of an optical wave to which a phase modulation is applied.
16 . The apparatus of claim 15 , wherein sets of nonlinear optical elements of the plurality of nonlinear optical elements are interspersed between sets of linear optical elements of the plurality of linear optical elements.
17 . The apparatus of claim 13 , wherein the plurality of linear optical elements is arranged over a first plane and the plurality of nonlinear optical elements is arranged over a second plane that is substantially parallel to the first plane.
18 . The apparatus of claim 17 , further comprising a reflective optical element that is coplanar with a third plane that is substantially parallel to the first plane, where the plurality of nonlinear optical elements is between the plurality of linear optical elements and the reflective optical element.
19 . The apparatus of claim 13 , wherein the plurality of linear optical elements is configured to sort optical waves into one or more optical modes of the sorted mode distribution based at least in part on a set of training data.
20 . The apparatus of claim 13 , wherein each nonlinear optical element of the plurality of nonlinear optical elements is configured to apply a change in an amplitude or a phase of an optical wave interacting with that nonlinear optical element of the plurality of nonlinear optical elements in response to an electric field or optical field applied to that nonlinear optical element of the plurality of nonlinear optical elements.
21 . A method comprising:
applying to an optical wave, using each linear optical elements of a plurality of linear optical elements, a change in amplitude or phase of the optical wave interacting with that linear optical element of the plurality of linear optical elements;
applying to the optical wave, using each nonlinear optical element of a plurality of nonlinear optical elements, a change in an amplitude or a phase of the optical wave interacting with that nonlinear optical element of the plurality of nonlinear optical elements, where the change in an amplitude or a phase is a nonlinear function of an amplitude or a phase of the optical wave; and
sorting, based at least in part on a collective change in amplitude or phase applied to the optical wave using the plurality of linear optical elements, portions of the optical wave into one or more optical modes of a sorted mode distribution;
wherein two or more nonlinear optical elements of the plurality of nonlinear optical elements are arranged to interact with the optical wave between successive interactions of the optical wave with two linear optical elements of different respective pairs of linear optical elements in the plurality of linear optical elements.
22 . The method of claim 21 , wherein each nonlinear optical element of the plurality of nonlinear optical elements is configured to apply a change in an amplitude or a phase of the optical wave interacting with that nonlinear optical element of the plurality of nonlinear optical elements in response to an electric field or optical field applied to that nonlinear optical element of the plurality of nonlinear optical elements.
23 . The method of claim 21 , wherein each of the plurality of linear optical elements and the plurality of nonlinear optical elements are arranged over a respective plurality of planes, where each plane of the plurality of planes is substantially parallel to a common plane that is substantially perpendicular to a propagation direction of an optical wave to which a phase modulation is applied.