OPTICAL PULSE DISTORTION MEASUREMENT LIMITATIONS IN LINEAR-TIME INVARIANT-SYSTEMS, AND APPLICATIONS TO POLARIZATION MODE DISPERSION

The optical pulse-distorting properties of a fiber network or device are sometimes deduced from spectral measurements or correlation measurements. In order to investigate the theoretical limitations on such deductions, single-mode optical networks are characterized in terms of linear, time-invariant filters. An optical impulse response is discussed which directly models pulse distortion in the time domain. This linear systems approach is then applied to measurements of polarization mode dispersion by Jones matrix eigenanalysis, low-coherence interferometry, and Fourier-transformed wavelength scanning (i.e. fixed analyzer) techniques. We show that, without restrictive assumptions of negligible chromatic dispersion, these techniques allow calculation of autocorrelations of output pulses, but not the output pulse shapes. We discuss the conditions under which chromatic dispersion may be neglected, and show that in this case the Jones matrix method allows calculation of the complete output pulse shape in response to an arbitrary input pulse.