METHOD FOR IMPARTING FLUCTUATION TO LIGHT SIGNAL

摘要

PURPOSE: To provide a bent part of an optical fiber which has a large modulation degree, is responsible with a high frequency as well and has no null point appearing in modulation of the plane of polarization even if the curvature of this bending part is not largely fluctuated. CONSTITUTION: A stimulus to change the phase of the light wave propagating in the optical fiber 1 is applied to the bending part 2 of the optical fiber 1 bent at the curvature at which the light radiated outside from the core of the optical fiber returns to the inner side and can be recoupled, by which the fluctuation is applied on this light signal. The stimulus is so applied that the curvature and bending width of the bending part 2 do not vary. The plural light signals varying in wavelengths are propagated in the optical fiber. The curvature of the bent part 1 and the wavelengths of the light signals are so selected that >=1 light signals among the plural light signals are not intensively affected and that the other >=1 light signals are intensively affected.