| 摘要 |
PURPOSE:To reduce insertion loss and to reduce the size and cost of an optical demultiplexer by uniting an optical branching device and the optical demultiplexer with each other. CONSTITUTION:Natural light with wavelength lambda2 is separated by a polarized wave separating element 2, where a P polarized wave component is passed and an S polarized wave component is reflected. The P polarized wave component is reflected by a mirror 8 and the S polarized component is reflected by a dielectric multilayered film filter 7 and incident on the polarized wave separating element 2 again. The P polarized wave component is passed and coupled with an output fiber 6 and the S polarized wave component is reflected and coupled with an output fiber 5. Light with wavelength lambda1, on the other hand, is incident on an input fiber 10 and then converted by a lens 9 into parallel light, which is passed through the dielectric multilayered film filter 7 and reflected totally by the polarized wave separating element 2 without being separated because its wavelength is short, so that the component is coupled with an optical fiber 4. Namely, light beams with wavelengths lambda1 and lambda2 are demultiplexed by the dielectric multilayered film filter 7 and the light with wavelength lambda2 is branched by the polarized wave separating element 2, so that two-way transmission of wavelengths lambda1 and lambda2 is realized. |
