| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter module satisfying the required insertion loss, of which the productivity is improved and the cost is reduced. SOLUTION: The filter module 21 has a first lens 22 and second lens 23 which are the same lenses prefixed to be made nearly coaxial, a filter 24 arranged between the two lenses 22 and 23, optical fibers 25 and 26 arranged on the incident side of the first lens 22 and fixed to nearly parallel to the fiber axes, and an optical fiber 27 arranged on the exit side of the second lens 23. If the focal lengths of the lenses 22 and 23 are defined as f, the deviation value from the focal position of the first lens 22 of the filter 24 is set within±25% of the focal lengths f. Such setting makes it possible to assemble the filter module having the insertion loss on the opposite side smaller than 0.2 dB without theθx andθy alignment of the optical fibers 25 to 27. COPYRIGHT: (C)2004,JPO |
