Wavelength division demultiplexing chip based on planar optical waveguide and optical module

The invention relates to the field of optical communication, in particular to a wavelength division demultiplexing chip based on a planar optical waveguide and an optical module. The chip mainly comprises an input waveguide, an input slab waveguide, an array waveguide grating and an output slab waveguide which are connected in sequence, wherein the output slab waveguide is respectively connected with m output waveguides; at least one diffraction grating is arranged on each output waveguide; the input slab waveguide, the array waveguide grating and the output slab waveguide act together to perform first demultiplexing on optical signals with n * m wavelengths, the optical signals with n * m wavelengths are decomposed into m paths of optical signals, and each path of optical signals comprises the optical signals with n wavelengths; the output waveguide is used for receiving one path of optical signal, and the diffraction grating is used for diffracting the optical signal with the predetermined wavelength so as