| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical wavegiude device having stable quality and transmission power by forming a diffraction grating of which diffracrtive index is changed periodically along the optical axis on a core part and arranging a high diffractive index area in the vicinity of the diffractive grating. SOLUTION: The diffraction grating 7 with a diffractive index difference in the optical axial direction of the core 2 is formed, and the high diffractive index area 3 is arranged in the vicinity of the diffraction grating 7 along the core 2. The optical wavegiode device of such a constitution is inserted into a line network of an optical fiber, and monitoring light is sent into it, and by observing reflection light from the diffraction grating 7, the condition of the line network is monitored. At this time, the monitoring light transmitting through the core 2 generates a high degree mode by the diffraction grating 7, and even when the high degree mode transmits through the diffraction grating 7, the high degree mode propagating with the large extent is coupled with the high diffractive index area 3 to be extinguished. On the other hand, since a basic mode transmits through the core 2 with the small extent, the basic mode hardly by coupled with the high diffractive index area 3 not to 6e extinguished by the high diffractive index area 3. |
