Distortion related to polarization-mode dispersion in analog lightwave systems

Abstract

Analog transmission in single-mode fiber using chirped sources gives rise to nonlinear distortion when polarization-mode dispersion (PMD) is present. We investigate experimentally and theoretically two mechanisms for this distortion: for chirped sources, PMD in the presence of polarization-mode coupling results in second-order distortion that is proportional to the square of the modulation frequency; when polarizationdependent loss is present, an additional second-order distortion term occurs that is independent of modulation frequency. Both mechanisms give rise to distortion that is time varying due to the sensitivity of PMD to ambient temperature changes. Numerical examples indicate that these effects can limit the capacity of analog systems that use directly modulated semiconductor lasers.

Principal states of polarization for an optical pulse in the presence of polarization-dependent loss and polarization mode dispersion

“…The effective PDL for the pulse in decibel unit (dB) is expressed as the logarithm ofthe ratio between the maximum and minimum transmission power ofa fiber [8], that is…”

Measurement of high-order polarization mode dispersion

“…In reality, however, this direct approach leads to significant errors in high-order derivatives since we are dealing with ratios of extremely small quatities, and minor measurement fluctuations may result in large deviation. Better accuracy can be achieved by numerically fitting the Jones matrix data to a polynomial of matrices T n () = A 0 + A 1 + A 2 2 + 111 + A n n , the degree of which depends on the number of terms to keep in the expansion (1). The derivatives of the Jones matrix are then given by the coefficients of this polynomial: T (k) j !…”

“…ITH the current trend toward ultrahigh bit rate transmission systems, the effects of second-and higher order PMD are becoming increasingly significant [1], [2]. It is thus important to find convenient ways to characterize these effects and measure them.…”

Optically Compensating the PMD-Induced RF Power Fading for Single-Sideband Subcarrier-Multiplexed Systems

“…However, deleterious RF power fading has been reported in the transmission of analog and digital SCM signals over fiber due to polarization mode dispersion (PMD) [1], [2]. PMD is caused primarily by the asymmetry of the optical fiber core that causes a birefringence such that light polarized along one axis will travel faster than light polarized along the orthogonal axis.…”