Patent ID: 7181115

Claim:
A dispersion compensating fiber module adapted to be connected to an existing optical fiber to suppress residual dispersion of the existing optical fiber to a low level, said dispersion compensating fiber module comprising: a dispersion compensating fiber which exhibits, at a wavelength of 1.55 μm, a chromatic dispersion and a dispersion slope of negative values, and a relative dispersion slope of between 0.006 nm −1 and 0.016 nm −1 ; and an optical fiber which exhibits, at a wavelength of 1.55 μm, a chromatic dispersion and a dispersion slope of positive values, and a relative dispersion slope of between 0.0028 nm −1 and 0.0036 nm −1 , wherein the dispersion compensating fiber module exhibits, at a wavelength of 1.55 μm, a relative dispersion slope of between 0.016 nm −1 and 0.026 nm −1 ; and, wherein when said dispersion compensating fiber module is connected to the existing optical fiber, a maximum residual dispersion difference of less than or equal to 0.4 ps/nm/km is exhibited in a wavelength range between 1.525 μm and 1.565 μm.