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Table 2 shows the typical PDL measurement capabilities of each method compared to possible performance requirements. The power and PDL ranges shown in this table will be referred to throughout this document. Use this table to decide which measurement method is most appropriate for a specific application. Table 2. PDL measurement method performance comparison Among the three methods offered, the Power Meter Method offers the highest single-wavelength PDL measurement accuracy. This method is well suited for general-purpose applications. The Power Max./Min. Method provides single-wavelength PDL data plus polarization state information about which relative states of polarization create maximum and minimum

The Agilent 11896A adjusts polarization and not power and is an important part of a PDL test system. Its optical fiber loop design, shown in Figure 2, provides all states of polarization (see Figure 3) with extremely small optical insertion-loss variations (0.004 dB) over a 1250 to 1600 nm spectral range. This performance combination maximizes measurement accuracy for power sensitive PDL measurements (see Figure 4). The Agilent 11896A adjusts the polarization of a transmitted signal as it passes through the internal four-fiber-loop assembly. Each loop’s dimensions are optimized to approach a quarter-wave retarder response over the controller’s specified wavelength range.

Polarization-dependent loss (PDL) for a component or system is the maximum, peak-to-peak insertion  loss (or gain) variation caused by a component when stimulated by all possible polarization states  (see Figure 1). It is specified in dB units. Polarization-dependent loss may also be referred to as  polarization sensitivity, polarization-dependent gain (PDG) or extinction ratio (for optical polarizers). Some components are designed for maximum PDL. A linear optical polarizer, for example,  must have high PDL in order to convert un-polarized light into linearly polarized light. Only one  orientation of linearly polarized light passes through the polarizer un-attenuated. Misaligned orientations  of polarized light

Why line coding ? There are many reasons for using line coding. Each of the line codes you will be examining offers one or more of the following advantages: Spectrum shaping and relocation without modulation or filtering. This is important in telephone line applications, for example, where the transfer characteristic has heavy attenuation below 300 Hz. Bit clock recovery can be simplified. DC component can be eliminated; this allows AC (capacitor or transformer) coupling between stages (as in telephone lines). Can control baseline wander (baseline wander shifts the position of the signal waveform relative to the detector threshold and leads

Theory When two single mode fibers are butted together to form a joint, the fundamental mode field of the source fiber is coupled into the modes of the recipient fiber. These recipient modes consist of the fundamental mode, lossy cladding modes and radiation modes. The magnitude of the source mode field coupled into each recipient mode is given by the overlap integral of the two modal electric fields. In the transverse offset technique, we are concerned with the transfer of optical power from the source mode into the same mode of an identical fiber when their axes are parallel but