Abstract: A method and apparatus for filter spectrum deconvolution and reshaping include providing a filter output of a spectrum signal and determining the intensity and wavelength of the spectrum signal at each spectral peak. The filter output is characterized as an integral of convolution of a spectrum signal function and a filter function. Transformation are then performed on the filter output to deconvolve and remove the undesirable filter function and add a desirable filter function to reshape the output filter spectrum.

Abstract: A method and apparatus for providing controllable second-order polarization mode dispersion for fiber optic transmission systems are provided. A section of fixed high birefringent optical fiber, a polarization controller, and a variable differential group delay module are provided. The polarization controller is connected to the optical fiber section, and the variable differential group delay module is connected to the polarization controller. The variable differential group delay module is controlled to vary the second-order polarization mode dispersion values at an output of the high birefringent optical fiber section.

Abstract: A method and apparatus for utilizing tunable differential group delay with at least a component of a fiber optic transmission system includes providing a tunable differential group delay system that is optically connected to a component of the fiber optic transmission system. The tunable differential group delay system is then controlled to insert differential group delay into the component of the fiber optic transmission system.

Abstract: A method and apparatus for providing controllable second-order polarization mode dispersion for fiber optic transmission systems are provided. A section of fixed high birefringent optical fiber, a polarization controller, and a variable differential group delay module are provided. The polarization controller is connected to the optical fiber section, and the variable differential group delay module is connected to the polarization controller. The variable differential group delay module is controlled to vary the second-order polarization mode dispersion values at an output of the high birefringent optical fiber section.

Abstract: A method and apparatus for providing tunable second-order polarization mode dispersion with constant mean first-order differential group delay for fiber optic transmission systems are provided. A section of fixed high birefringent optical fiber, a polarization controller, and a variable differential group delay module are provided. The polarization controller is connected to the high birefringent optical fiber section, and the variable differential group delay module is connected to the polarization controller. The variable differential group delay module is controlled to vary the second-order polarization mode dispersion values at an output of the high birefringent optical fiber section. The polarization controller is controlled to hold the mean first-order differential group delay substantially constant at the output of the high birefringent optical fiber section for each value of the second-order polarization mode dispersion at the output of the high birefringent optical fiber section.