Questions and Answers on Basic Knowledge of Fiber Optic Cables In currently commercial optical fibers, what wavelength of light has small dispersion? What wavelength of light has small loss?
Answer: Light with a wavelength of 1310nm has small dispersion, and light with a wavelength of 1550nm has small loss.
Answer: It can be divided into step fiber and gradient fiber.The step optical fiber has a narrow bandwidth and is suitable for small-capacity short-distance communications; the gradient optical fiber has a wider bandwidth and is suitable for medium and large-capacity communications.
Answer: It can be divided into single-mode optical fiber and multi-mode optical fiber.
The core diameter of single-mode optical fiber is approximately between 1 and 10 μm. At a given operating wavelength, it only transmits a single fundamental mode and is suitable for large-capacity and long-distance communication systems.
Multi-mode optical fiber can transmit multiple modes of light waves, with a core diameter of approximately 50 to 60 μm, and its transmission performance is worse than that of single-mode optical fiber.
When transmitting current differential protection of multiplexing protection, multi-mode optical fiber is often used between the photoelectric conversion device installed in the substation communication room and the protection device installed in the main control room.
Answer: The numerical aperture (NA) indicates the light-collecting ability of the optical fiber. The larger the NA, the stronger the optical fiber's ability to collect light.
Answer: There are two orthogonal polarization modes in single-mode fiber. When the fiber is not completely cylindrically symmetrical, the two orthogonal polarization modes are not degenerate, and the two orthogonal polarization modes are refracted. The value of the difference in rates is birefringence.
