| 摘要 |
PROBLEM TO BE SOLVED: To increase the quenching ratio of a multi-function integrated optical chip (MIOC) and to improve the operation efficiency an absorbing cover body by laminating a layer having a selected high refraction factor and a low refraction factor. SOLUTION: An absorbing layer 26 is formed by deposition on a MIOC, and a mount 28 is provided on the absorbing layer 26 to form this light absorbing device 25 for preventing reflection. The mount 28 is made of SiO2 , and the absorbing layer 26 is preferably made of SnTe. The absorbing layer 26 is similar to a 1/4-wavelength reflection preventing cover body as a single layer, and the refraction factor of the mount 28 is selected to generate interface internal total reflection between the absorbing layer 26 and the mount 28. The thickness of the 1/4-wavelength layer has the reciprocation length of the 1/2-wavelength, thus the phase of the light from a mount interface is drifted by 180 deg. from the phase of the light of an external layer interface. Two interface reflections negate each other due to this phase difference, thereby no reflection is generated from the whole system with the selected wavelength. |
