| 摘要 |
By urging an ordinary single-mode (usually dispersion-shifted) fiber into an external, long-period mechanical grating, a highly wavelength- selective coupling between the fiber's guiding mode and a cladding mode is induced. A sequence of such induced gratings, all on the same fiber, can be used to create a many tens of nm wide loss band of arbitrary shape, with resolution of 3 nm or better, whose strength at any wavelength can be continuously adjusted from zero to -17 dB or more. With its simplicity, near ly zero background loss, and especially, with its potential for continual readjustment, the device is ideal for dynamic gain equalization of optical amplifiers.
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