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Polarization-Maintaining Single-Mode Fiber Cables PMC and PMC-E

Polarization-maintaining singlemode fibers guide coupled radiation in two perpendicular principle states, the fiber polarization axes. For the two polarization axes the speeds of propagation is different, denoted the fast and slow fiber axes.

Linearly polarized radiation not coupled exactly into one of these axes is transformed into an elliptical state of polarization because of these different speeds of propagation.

The linearly polarized laser radiation is conventionally coupled into the slow axis, because of its lower sensitivity to fiber bending.

In polarization-maintaining fibers the rotational symmetry is made void by birefringence. The birefringence is achieved by stress-inducing components in the fiber cladding, such as in “PANDA“ fibers and “Bow-Tie“ fibers or by an oval clad such as in “Oval-Inner Clad“ fibers. The slow axis is orientated in parallel with the stress-inducing elements (“PANDA“ and “Bow-Tie“ fiber) or in parallel with the larger diameter of the inner cladding (“Oval-Inner Clad“ fiber).

The polarization-maintaining fiber cables made by Schäfter+Kirchhoff typically use fibers of type PANDA. The slow axis is aligned with the index key of the FC type fiber connector with high precision (< 1.5°).

The fiber cables made by Schäfter+Kirchhoff typically have a polarization extinction > 200:1 (23 dB) or > 400:1 (26 dB) for λ > 780 nm.

Performance Features

  • Polarization-maintaining singlemode
  • Wavelength 360 – 1800 nm (Cut-off wavelengths from 360 to 1550 nm), each with an operational wavelength range of 100 – 300 nm (depending on cut-off wavelength)
  • Mode field diameter 2.9 – 12 μm
  • Special broadband fiber RGBV with an operational wavelength range 400 – 680 nm
  • Fiber with low attenuation (Si) for wavelengths < 460 nm
  • FC-APC or FC-PC fiber connector (other connector types available)
  • Amagnetic titan connectors available for FC-APC or FC-PC connectors
  • Polarization direction is indicated by connector index key
  • Optionally: Connectors with end caps for all fibers for reduced power density at the fiber end face (one or both ends)

The three defining parameters of a polarization-maintaining singlemode fiber are effective numerical aperture NA, mode field diameter MFD and cut-off wavelength λco. Because of manufacturing tolerances, the mean specified values for NA and MFD may differ by up to 10%.

Carefully selected fibers with characterized values are available on request. Using fibers with end caps reduces the risk of damaging the fiber end face, by reducing the power density but without changing the numerical aperture NA of the fiber.

Schäfter + Kirchhoff GmbH - specialists for optical sensors and measurement technology
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