Optical signal processing apparatus

An optical signal processing apparatus comprising:

• wavelength separation means for receiving multiplexed signal light having multiple wavelengths λ1 to λN (λn−1<λn;
• N is an integer, 2≦N;
• n is an integer, 2≦n≦N), separating the multi-wavelength signal light into signal light components of respective wavelengths, and outputting the separated signal light components of the respective wavelengths to spatially different optical paths;
• and
• optical path changing means for changing the optical paths of the signal light components of the respective wavelengths output from said wavelength separation means,
• wherein for a first signal light component (wavelength λn−1) and second signal light component (wavelength λn), which have adjacent wavelengths in the signal light components with the multiple wavelengths, letting G be a position at which the multi-wavelength signal light is wavelength-separated by said wavelength separation means, Pn−1 be a position at which an optical path of the first signal light component is changed by said optical path changing means, Ln−1, be a distance from the position G to the position Pn−1 along the optical path of the first signal light component, and Pn be a position which is located on an optical path of the second signal light component from the position G to said optical path changing means or on an extended line of the optical path, and separated from the position G by the distance Ln−1, a distance between the optical paths of the first and second signal light components, which are changed by said optical path changing means, is set to be larger than a distance between the position Pn−1 and the position Pn.