| 摘要 |
PURPOSE:To provide a diffraction element capable of using one element for plural wavelength band and to provide an optical multiplexing/demultiplexing device using the effect of this diffraction element. CONSTITUTION:The diffraction element comprises a transparent substrate 2 having a first and a second surfaces, a periodic groove marked on the first surface, a reflection film 1 provided on the groove and an anti-reflection film 4 provided on the second surface. The multiplexing/demultiplexing device having the diffraction element is provided with a first optical input device 10 making a light beam incident on the first incident plane of the diffraction element (the first surface side provided with the reflection film), a first light receiving device 12 receiving a light beam made incident on the first incident plane and diffracted, a second optical input device 11 receiving a light beam reflected after being made incident on the first incident plane and making it incident on the second incident plane of the diffraction element (the surface provided with the anti-reflection film) and a second light receiving device 13 receiving the light beam made incident on the second surface and diffracted. |
