An analytical formula for the mean differential group delay of randomly birefringent spun fibers

Abstract

Abstract-Polarization-mode dispersion (PMD) is a serious impairment for high-bit-rate optical telecommunication systems. It is known that spinning the fiber during the drawing process drastically reduces the PMD. However, the analysis of pulse propagation through a randomly birefringent spun fiber is still at an early stage. In this paper, we derive an analytical formula for the mean differential group delay of a periodically spun fiber with random birefringence. We model the birefringence with fixed modulus and a random orientation under the condition that the spin period is shorter than the beat length. Finally, we numerically compare the analytical results with those given by the random-modulus model of birefringence, and we obtain good agreement as long as the short-period assumption is satisfied.Index Terms-Beat length, birefringence correlation length, fiber birefringence, polarization-mode dispersion (PMD), spun fibers.

Virtually Isotropic Transmission Media With Fiber Raman Amplifier

“…It is well known that the SIRF for the periodic spin rate can reach the minimum value of less than 0.01 for the phasematching condition A 0 1.2 [5]. It means that Eq.…”

“…Otherwise, the SIRF is calculated as follows [5] (6) 2,3) are the averaged and normalized components of the PMD vector, , and (z')= A(z')/ z' is the spin rate.…”

Two-Section Fiber Optic Raman Polarizer

“…To calculate spin induced reduction factor (SIRF) for the case of spun fiber we use the standard model of PMD [3] ( ) ( ) ,…”

“…PMD is caused by varying group velocities for the pulses with different states of polarization (SOPs) and so leads to pulse broadening [1][2][3]. Varying signal SOPs at the input of fiber Raman amplifier leads to uncontrollable output gain variation.…”

“…Maximum of the gain variation is defined as polarization dependent gain (PDG) [4][5][6][7][8]. Traditional PMD suppression technique is based on spinning the fiber periodically and results in PMD suppression below 0.04 ps/km 1/2 [2,3]. However, this PMD suppression is accompanied with a simultaneous increase in the Raman PDG [5][6][7][8].…”