LONG-WAVELENGTH LIGHT INTERCEPTING FILTER AND OPTICAL WAVELENGTH MULTIPLEXING CIRCUIT

摘要

PURPOSE: To provide an economical and effective longwavelength light intercepting filter by easily controlling the cut-off wavelength and the attenuation characteristic and reducing the number of parts and simplifying the adjustment and reducing the loss and miniaturizing the filter. CONSTITUTION: A long-wavelength light intercepting filter device 11 consists of an optical fiber 12 wound with a certain curvature and is coupled to an optical path 14 with an optical connector 13 between them. Since the long- wavelength light intercepting filter device 11 has this very simple constitution, the number of parts can be reduced and the device can be miniaturized. The cut-off wavelength and the attenuation characteristic are easily controlled by the radius of winding of the optical fiber 12 and the number of turns of the optical fiber respectively. Since the optical path is completely in the optical fiber, the loss is reduced and coupling is easily adjusted.