| 摘要 |
PURPOSE:To facilitate bidirectional communication with one optical fiber and lights different in wavelength by forming interference film filters, which have optical coupling and branching functions, on rod lenses and providing these rod lenses in the up side and the down side. CONSTITUTION:Interference film filters F23 and 24 and similar filters 28 and 29 are attached to rod lenses 22 and 27, which are provided in both ends of an optical fiber 7, through spacers 25 and 30. The F23 permits the light having a wavelength lambda1 to transmit through, but reflects lights having wavelengths lambda2 and lambda3, and the F24 permits lights having wavelengths lambda1 and lambda2 to transmit through, but reflects the light having the wavelength lambda3, and the F28 permits lights having wavelengths lambda1 and lambda3 to transmit through, but reflects the light having the wavelength lambda2, and F29 permits the light having the wavelength lambda3 to transmit through, but reflects lights having wavelengths lambda1 and lambda2. For example, the light having the wavelength lambda1 from a semiconductor laser LD1 passes a lens 2, the F23, the spacer 25, the F24, the rod lens 22, the fiber 7, the rod lens 27, the F28, and the spacer 30 and is reflected on the F29 and is made incident on an optical fiber 9 in the condensation position. Similarly, the light having the wavelength lambda2 from a laser LD1'' is made incident on an optical fiber 35, and the light having the wavelength lambda3 from a laser LD1' is made incident on an optical fiber 33. Thus, bidirectional communication with wavelengths lambda1, lambda2, and lambda3 is performed easily by only one optical fiber 7. |
