Measurement of polarization mode coupling along a polarization-maintaining optical fiber using a backscattering technique

Abstract

A new technique for measuring the polarization mode coupling of a polarization-maintaining optical fiber has been proposed that uses a modified optical time-domain reflectometry in which two kinds of backscattered signals coming through each principal axis of the fiber are utilized. This technique shows how the mode coupling occurs along the fiber. The extinction ratio evaluated by the present technique is in good agreement with that obtained by a conventional technique (within +/-0.5 dB).

Review of long wavelength single-mode optical fiber reflectometry techniques

“…The modulation in this trace is due to the varying efficiency with which the partially (or totally) polarized backscatter signal from different locations along the fiber passes the analyzer. This technique has been used to measure polarization mode-coupling along a nominally polarization maintaining fiber at long wavelength [21], [22]. Fig.…”

“…Later [36] the performance was improved to 27.5 dB, probably as a result of improved optics. The large dynamic range of this type of system has also been used to allow measurements of the small polarization mode coupling along a polarization maintaining fiber [21], [22] by the POTDR technique [2]. More recently, attention has focused on measurements at 1.55 pm using the Er3' laser.…”

Detailed comparison between mode couplings along multi-core fibers and structural irregularities using a synchronous multi-channel OTDR system with a high dynamic range

“…where h n,1 is the mode coupling coefficient between cores 1 and n, L is the fiber length, and K is a constant determined by the Fourier transformation of the autocorrelation function of the mode coupling coefficient [12,13] and the crosstalk caused by the fan-in device. An optical amplifier (EDFA) and an optical masking apparatus to remove the deadzone caused by the Fresnel reflections generated at both the input and output ends of the MCF were newly adopted in the OTDR system.…”

Extremely Advanced Transmission with 3M Technologies (Multi-level Modulation, Multi-core & Multi-mode)

“…The OTDR technique has been found to be very useful for evaluating the polarization mode coupling that occurs locally along a polarization-maintaining fiber [12,13]. A schematic diagram of the MCF mode coupling measurement and the experimental results are shown in Fig.…”

“…It is important to note that this technique also clarifies the nonuniformity of the mode coupling coefficient along the fiber caused by the structural irregularity of the fiber. Furthermore, the power ratio is proportional to the fiber length, with the slope given by twice the mode-coupling coefficient [12,13]. We can therefore obtain the modecoupling coefficient by taking the derivative of the power ratio, which is shown in Fig.…”