Optical fiber with sharp optical absorptions by vibrational-rotational absorption of C/sub 2/H/sub 2/ molecules

An optical fiber with sharp optical absorption peaks in the wavelength region from 1.515 to 1.535 mu m is discussed. These absorption peaks are provided by the vibrational-rotational absorption of C/sub 2/H/sub 2/ molecules (VRAM) placed inside the small vacant hole of the core center. Each peak has a FWHM bandwidth of 9.8 GHz and an absorption of between 1 and 5 dB for the 300-m-long fiber.<
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