| 摘要 |
PURPOSE:To obtain an optical polarized branching filter having a small degree of loss, by forming a pair of buried parallel rectangular waveguide paths plus a cladding layer by adding a prescribed dopant on a quartz substrate and setting the length of the waveguide path at a prescribed coupling length. CONSTITUTION:A pair of baried rectangular cores 9 made of SiO2 obtained by adding 8wt% GeO2 and 12wt% B2O3 together is formed on a quartz substrate 8. Then a cladding layer 10 made of SiO2 obtained by adding 5wt% GeO2 and 15wt% B2O3 together is provided on the core 9. The coupling length L is set so as to satisfy Kx-Ky=pi/L(1/2+n), n=0, + or -1- where Kx is the interwaveguide path coupling coefficient to the light having its polarized face in the (x) direction parallel to the substrate 8 and Ky is the coupling coefficient of the light having its polarized face in the (y) direction. As a result, an optical polarized wave coupler having a small degree of loss is obtained. |
