| 摘要 |
PROBLEM TO BE SOLVED: To provide good optical transfer with reduce noise index. SOLUTION: An optical circulator 2 comprising four pots 2a-2d which are optical input/output terminals, two EDFs 3 and 4 each of which connected to first ports 2a and 2c among the ports 2a-2d of the optical circulator 2, respectively comprise ports 3a and 4a at their circulator inverse connection side end parts, and wavelength-selecting filters 11 and 12 which, connected to the EDFs 3 and 4 via the second ports 2b and 2d among the ports 2a-2d of the optical circulator 2, reflect optical signal of specific wavelength are provided. Here, excitation light sources 13 and 14 for exciting EDFs 7 and 8 are connected to the optical path (couplers 9 and 10) of the wavelength-selecting filters 11 and 12. |
