| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunable optical filter having a variable stop band and stable characteristics in the case of using the filter as a light adding/dropping circuit. SOLUTION: The optical filter is provided with a 1st port 24, an optical filter member 28 whose characteristics are changed in accordance with a position in a previously determined direction, a 2nd port 32 to be optically connected to the 1st port 24 by a transmitting optical path formed by the member 28, a reflection unit 36 to be optically connected to the 1st port 24 by a reflecting optical path formed by the member 28, and a mechanism 38 for displacing the member 28 in a previously determined direction. |
