Optical waveguide filter

摘要

It is an object of the present invention to provide an optical filter which allows parameters to be easily adjusted, which allows birefringence and temperature dependence to be easily compensated for, and which is essentially free from dispersion. The optical filter includes an optical coupler (12) that splits light into two beams, optical couplers (13a, 13b) connected to outputs of the optical coupler (12), a first group of two optical waveguide delay lines (14a and 14b) connected to the coupler (13a), a second group of two optical waveguide delay lines (15a and 15b) connected to the coupler (13b), an optical coupler (16a) that combines lights from the first group of the lines (14a and 14b) , an optical coupler (16b) that combines lights from the second group of the lines (15a and 15b), and a multimode interference optical coupler (17) that combines lights from the couplers (16a and 16b) together. <IMAGE>