Encoding device and decoding device

An encoding device, comprising:

• an encoding unit configured to perform an encoding process of inputting N intensity signals (N is an integer greater than or equal to 2) of (M+1) values (M is an integer greater than or equal to 1) and adding (2LM/2) (L is an integer less than or equal to 1 and 2L is less than or equal to N) to an encoded signal having a negative minimum value in a range of the encoded signal among encoded signals of 2L channels of (2LM+1) values obtained by calculating an inner product of a Hadamard matrix of 2L rows and 2L columns and a matrix having elements of 2L intensity signals included in a set for each set of 2L intensity signals and generate encoded signals of N channels;
• N digital-to-analog conversion units corresponding to the N channels and configured to convert the encoded signals of the N channels from digital signals into electrical analog signals;
• N light sources corresponding to the N channels and configured to output light of wavelengths for use in the N channels;
• N light intensity modulation units corresponding to the N channels and configured to intensity-modulate the light output from the N light sources with the encoded signals converted into the electrical analog signals by the N digital-to-analog conversion units;
• and
• a wavelength multiplexing unit configured to output a wavelength-multiplexed signal obtained by wavelength-multiplexing the light intensity-modulated by the N light intensity modulation units.