Narrow-bandpass filter with gain by use of twin-core rare-earth-doped fiber.
We demonstrate both numerically and experimentally that rare-earth-doped twin-core fiber couplers can function as a narrow-bandpass wavelength filter or as a demultiplexer. The experimental bandwidth obtained is 6.5 nm. In addition, the filtered signal experiences a gain of 20 dB instead of attenuation.
Wu
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B
Chu
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