| 摘要 |
PROBLEM TO BE SOLVED: To mainly obtain an optical multiplexer and an optical demultiplexer having a small insertion loss and small deviation of insertion loss in an optical device, terminal apparatus, and a system for wavelength division multiplex(WDM). SOLUTION: The optical device is provided with a fiber collimator 24 and plural fiber assemblies 28 which are successively optically coupled with the fiber collimator by reflected light paths 26 of approximately parallel beams. The fiber collimator 24 contains an optical fiber 34 and a lense 36 which is installed so as to face the optical fiber 34. Respective fiber assemblies 28 contain an optical filter 42 for providing the reflected light path, an optical fiber 44 which is optically coupled with the optical filter by its transmission light path and a lense 46 installed between the optical filter and the optical fiber. The lense of the i-th fiber assembly has a focal distance which is equal to or larger than the focal distance of the lense of the (i-1)th fiber assembly. By this constitution, derivation of the coupling loss or the insertion loss caused by beam divergence in the reflected light path is small. |
