| 摘要 |
PURPOSE:To improve the convergence efficiency of a lens of the optical multiplexing and demultiplexing device and to hold characteristics of a filter constant, to prevent reflected light from returning to a light source, and to decrease the number of lenses by arranging an optical fiber near the optical axis of the lens and installing the filter at a specific angle to an incident light beam. CONSTITUTION:Light beams of wavelengths lambda1 and lambda4 propagating in an optical fiber 22 for transmission are collimated by a cylindrical distributed index lens 27 into parallel beams, which are incident on a prism 30. The filter 33 is installed on one surface of the prism 30 at an angle alpha to a surface perpendicular to the optical axis, and the light of wavelength lambda1 is reflected by this filter 33, transmitted through a filter 32 installed on a surface (a) of the prism 30 slanting by an angle beta from the surface perpendicular to the optical axis, and converged on an optical fiber 23 through a lens 28. The light of wavelength lambda4, on the other hand, is transmitted through a prism 31, filter 34, and filter 35 and then converged on an optical fiber 26 through a lens 29. Further, light of wavelength lambda2 is reflected by the filter 34 and light of wavelength lambda3 is reflected by the filter 35; and both are converged on the optical fiber 22. |
