2024-12-26 0

A Comprehensive Guide to Fiber Optic Cables

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What is an Optical Cable?

To protect optical fibers during installation, multiple optical fibers are combined using protective measures such as sheathing, twisting, plastic coating, and metal armoring, forming an optical cable.

An optical cable is a communication cable component that uses one or more optical fibers enclosed in a protective jacket as the transmission medium, and it can be used individually or in groups.

The basic structure of an optical cable typically consists of several parts: the core, reinforcing steel wires, filler material, and the outer jacket. Depending on the requirements, the cable may also include additional components such as a waterproof layer, buffer layer, and insulating metal conductors.

 

Classification Based on Core Structure

Optical cables can be classified into the following types based on the core structure: layer-stranded, skeleton-type, ribbon, and bundle. The most commonly used are ribbon optical cables and bundle optical cables.

  1. Ribbon Optical Cable: The optical fibers inside are arranged in rows in color sequence, with each row fixed in place, forming a ribbon-like structure.
  2. Bundle Optical Cable: The optical fibers are not arranged in any particular order, with each optical fiber being independent.

Can Ribbon and Bundle Optical Cables Be Spliced?Ribbon and bundle optical cables cannot be directly spliced. Additionally, splicing these cables results in higher connection loss, so this is generally not recommended.

 

Classification Based on FTTH Network Structure

Optical cables used in FTTH (Fiber to the Home) networks can be classified as feeder cables, distribution cables, and drop cables.

  1. Feeder Optical Cable: This type of optical cable runs from the central machine room’s optical distribution frame (ODF) to the optical distribution point (FDT). It is used for long-distance coverage and allows multiple users’ optical fiber lines to be split via the ODF and then transmitted to the optical distribution point for secondary splitting. A single FDT typically serves an entire neighborhood or a street.

Commonly Used Cables:

  • Duct Installation: Preferred type is GY(F)TY (cost-effective).
  • Overhead Installation: Preferred type is GY(F)TC8Y.
  • Direct Burial Installation: Preferred type is GY(F)TY53.
  • Blown Cable Installation: Choose GCYFY.

Factors Influencing Optical Cable Selection:

  • The total number of users determines the number of fibers in the optical cable.
  • The method of optical cable installation: duct, direct burial, overhead, or blown.
  • The cost of the optical cable, including material and installation costs.
  • Distribution Optical Cable: This type connects from the optical distribution point (FDT) to the fiber access terminal (FAT) and allocates optical fibers to the surrounding area. A single FAT typically covers a building corridor or a small residential area.

Commonly Used Cables:

  • Outdoor Installation: Supports duct, overhead, direct burial, or blown installation, commonly using the same types as feeder cables.
  • Indoor Installation: Common types are GJPFJH, GJPFXJH.

Factors Influencing Optical Cable Selection:

  • Optical cable characteristics such as density, diameter, flexibility, and weight.
  • Construction factors, including ease of branching and high splicing efficiency.
  • Drop Optical Cable: This type of optical cable connects from the fiber access point to the terminal (ONT), providing fiber-to-home connections.

Commonly Used Cables:

  • Low-Smoke, Zero-Halogen (LSZH) outer jackets, meeting ROSH standards.
  • Indoor Butterfly Optical Cable (GJXFH) for use inside buildings.

Factors Influencing Optical Cable Selection:

  • Optical cable characteristics such as excellent bending performance, resistance to side pressure, and resistance to twisting. The structure should be simple and easy to strip.
  • Construction factors, including the ability to terminate fibers on-site.