Reservoir computing operations using multiple propagations through a multi-mode waveguide

An apparatus for performing an operation on an input signal, the apparatus comprising:

• a multi-mode waveguide configured to receive the input signal imposed on laser light,
• the waveguide further configured to propagate the received input signal imposed on the laser light through the waveguide a plurality of times in a plurality of modes, the modes interfering each time they propagate through the waveguide to generate an interference pattern of the plurality of modes;
• a nonlinear optical medium configured to nonlinearly activate portions of the interference pattern of the plurality of modes each time those modes propagate through the multi-mode waveguide;
• and
• an optical detector array configured to receive output activated portions of the interference pattern of the plurality of modes in parallel with one another each time those modes propagate through the multi-mode waveguide.