All-fiber spectral filters with nonperiodic bandpass characteristics and high extinction ratios in the wavelength range 0.8 mu m< lambda <1.6 mu m

A simple modification is proposed to the dual-core spectral filter design which extends the range of single wavelength transmission considerably, making the filter characteristic nonperiodic in the wavelength range 0.8 mu m< lambda <1.6 mu m. Also, a spectral filter based on collinear triple-core fiber is proposed which provides a substantially lower sidelobe level than the dual-core filter. Transmission characteristics of the proposed filters are calculated and compared with those of the unmodified dual-core filter. The advantages of the proposed filters, particularly for application in wavelength division multiplexed systems are addressed.<
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