The guided wave road type optical combination dividing filter and the module null for optical transmission which uses

摘要

PURPOSE:To miniaturize and to have low loss by increasing the interval between two output waveguides of a 1st directional coupler by bending the output waveguides polygonally at a desired angle, and then putting other core waveguides close to linear waveguide parts extending linearly from the bent part and constituting a 2nd and 3rd directional coupler. CONSTITUTION:The 1st directional coupler 11 is constituted by putting the two nearly rectangular core waveguides 1 and 2 close to each other, and the two output core waveguides are bent outward polygonally at the desired angle theta/2 and then extended linearly from the bent part 3 and expanded linearly at the output core waveguide interval G. The 2nd and 3rd directional couplers 12 and 13 are constituted by putting other nearly rectangular core waveguides 6 and 7 close to the two linear waveguide parts 4 and 5 respectively, and one of the two output waveguides (4 or 7) is bent inwardly polygonally at the desired angle theta/2 and extended linearly from bent parts 8 and 9. Consequently, the miniaturization and the low waveguide propagation loss are realized.