Wave transmission medium and waveguide circuit

An optical circuit configured by using a waveguide circuit that is configured by two-dimensional placement of a wave transmission medium, said wave transmission medium comprising:

• a spatial refractive index distribution determined such that input-light launched into an input port propagates through the wave transmission medium with scattered multiple times to an output port, the input port being defined as any one of a plurality of ports, the output port being defined as at least one of the rest of the plurality of ports, and the light at the output port being defined as output-light;
• wherein the spatial refractive index distribution is designated by each refractive index of pixels defined by a mesh,
• said each refractive index of the pixels is determined by repeating calculations until a phase difference between a forward propagation of an input field of the input-light and a reverse propagation of an output field of the output-light becomes less than a desired value at each pixel, and
• the spatial refractive index distribution is implemented by local refractive index variations of said waveguide circuit based on electrooptic effect.

An optical circuit having a waveguide region configured on a substrate, the optical circuit comprising:

• a wave transmission medium having a spatial refractive index distribution, said spatial refractive index distribution being determined such that input-light launched into an input port propagates through the wave transmission medium with scattered multiple times to an output port, the input port being defined as any one of a plurality of ports, the output port being defined as at least one of the rest of the plurality of ports, and the light at the output port being defined as output-light;
• wherein the spatial refractive index distribution is designated by each refractive index of pixels defined by a mesh,
• said each refractive index of the pixels is determined by repeating calculations until a phase difference between a forward propagation of an input field of the input-light and a reverse propagation of an output field of the output-light becomes less than a desired value at each pixel, and
• individual refractive indices of said pixels are determined such that the light is confined in a direction perpendicular to said substrate.

An arrayed waveguide grating type optical multi/demultiplexer configured by using a waveguide circuit that is configured by two-dimensional placement of a wave transmission medium, said wave transmission medium comprising:

• a spatial refractive index distribution determined such that incident light launched into an input port propagates through the wave transmission medium with scattered multiple times;
• wherein local positions in the wave transmission medium are designated by virtual pixels defined by a virtual mesh,
• the spatial refractive index distribution of the wave transmission medium is formed by refractive indices of the individual pixels, and
• said arrayed waveguide grating type optical multi/demultiplexer comprises
• an input waveguide, a first slab waveguide, arrayed waveguides, a second slab waveguide and output waveguides, which are connected sequentially on a planar substrate;
• and
• a plurality of scattering points with a refractive index higher than a refractive index of said input waveguide, said scattering points being placed in a connecting region between said input waveguide and said first slab waveguide.

An arrayed waveguide grating type optical multi/demultiplexer comprising:

• an input waveguide, a first slab waveguide, arrayed waveguides, a second slab waveguide, and output waveguides connected sequentially on a planar substrate, and
• a wave transmission medium having a spatial refractive index distribution, said wave transmission medium being placed in a connecting region between said input waveguide and said first slab waveguide, said spatial refractive index distribution being determined such that input-light launched into the input waveguide propagates through the wave transmission medium with scattered multiple times to the first slab waveguide as output-light;
• wherein the spatial refractive index distribution is designated by each refractive index of pixels defined by a mesh, and
• said each refractive index of the pixels is determined by repeating calculations until a phase difference between a forward propagation of an input field of the input-light and a reverse propagation of an output field of the output-light becomes less than a desired value at each pixel.