| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a light amplifier which provides a variable light attenuator with a small insertion loss, with a simple constitution, compensates temperature dependency of the amplification characteristics of gain mediums such as EDF, and are free from characteristics variation by a temperature. SOLUTION: In a long-period fiber grating which has a phase shift area 3, when the temperature change occurs, the phase shift amount is varied and, thereby, transmission loss characteristics are varied. The temperature dependency of amplification characteristics is compensated by setting the temperature dependency of the transmission loss characteristics of this phase shift type long-period fiber grating to the opposite of the temperature dependency of the gain of the optical amplification mediums such as EDF, and the light amplifier free from the characteristics variation by the temperature can be obtained.</p> |
