Characterization of the polarization in the spun fibers

Abstract

The polarization mode dispersion (PMD) is a difficult phenomenon to compensate in the optical fiber. Its reduction can be achieved by the spinning process that provokes the rotation of the birefringence axes of the fiber inciting a coupling of its modes that is controlled at the time of its manufacture. In this work, the Jones Matrix Eigen-Analysis method (JME) is used to characterize the spun fibers to evaluate their PMD and to prove that it is distinctly lower than the standards fibers PMD. Furthermore, the differential group delays (DGD) of spun fibers is determined using the photon counting optical time-domain reflectometry (C-OTDR) method. The obtained results are compared with those found in the JME method. It is noted that the two methods yield practically identical values. The determination of the beat length and the spin period of spun fibers are carried out using the polarization-sensitive optical frequency-domain reflectometer (POFDR).

Spun Fibres for Compensation of PMD: Theory and Characterization

“…The OFDR method is not exploited again especially for investigating of the spun fibres for the determination of its parameters and of their PMD according to the distance. In this section, we will present the relation already demonstrated experimentally by COTDR in our anterior works (Cherbi et al, 2009) existing between the spatial period of the backscattered signal and the PMD of the spun fibre and given by (Chen, 2003). Even more, the COTDR method allowed us to compare the results found with those of the JME method.…”

“…The main difference of this reflectometer (Cherbi et al, 2009) compared to a classic OTDR (Ellison & Siddiqui, 1998) resides in the use of photon counting detector (InGaAs avalanche photodiode). It is used in the so-called gated Geiger mode, which means that the detector is only active during a short time slot.…”

“…Even more, the COTDR method allowed us to compare the results found with those of the JME method. Afterward we will present the POFDR method which used for spun fibres (Cherbi et al, 2009;Wegmuller et al, 2005) to obtain the beat lengths of the two types of spun fibres and the spin period of the bidirectional fibre. Chen ( Chen, 2003) has demonstrated that the spatial period of the backscattered signals obtained from a POTDR (polarization-sensitive optical time-domain reflectometer) of the spun fibres varies linearly with the beat length of the fibre.…”

“…Next, the description of the reduction of the PMD by using the spinning is developed by a mathematical formalism based on the theory of coupling and Jones's matrix. Moreover, the reduction of the PMD is verified in the spun fibres while applying the method of JME and the COTDR method (photon counting -Optical temporal Domain of Reflectometry) that allowed us to measure the DGD of the order of femtosecond (Cherbi et al, 2009). The comparison of the DGD found in this type of new generation of fibres with those of the standard ones, led us to confirm that the spun fibres offer effectively a smaller DGD than those of the standard fibres, emphasizing the importance of this type of fibres in the reduction of the PMD.…”

“…The comparison of the DGD found in this type of new generation of fibres with those of the standard ones, led us to confirm that the spun fibres offer effectively a smaller DGD than those of the standard fibres, emphasizing the importance of this type of fibres in the reduction of the PMD. We present the different results already published (Cherbi et al, 2009) while using the reflectometers COTDR and POFDR (polarization-Optical Frequency Domain of Reflectometry) which are used to get the polarization characteristics of the spun fibres as the beat length and the PMD and to observe the spatial frequencies linked directly to the period of spinning.…”