Managing optical nonlinearities and optical mode sorting

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.

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.

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.