Fiber optic cable types and applications
Model Composition:
1) Model Composition Contents: The model consists of two main parts: type and specifications.
2) Model Composition Format: The format of the optical cable model composition is shown in Figure 2-26.
The model number consists
The model number consists of five parts, each represented by a code, as shown in Figure 2-27. The structural features refer to the cable core structure and the optical cable derivative structure.
1) Classification code:
GY-Indoor (field) optical fiber cable for communication
GM – Mobile optical fiber cable for communication
GJ – Indoor optical fiber cable for communication
GS – Optical fiber cable for communication equipment
GH – Submarine optical fiber cable for communication
GT – Special optical fiber cable for communication
2) Code for reinforcing components:
Reinforcing components refer to components inside or embedded in the sheath used to enhance the tensile strength of the optical cable.
(Unsigned) - A metallic reinforcing member
F - A non-metallic reinforcing member
3) Structural Feature Codes: The structural features of the optical cable should indicate the main type of the cable core and the derived structures of the optical cable. When several structural features of the optical cable type need to be specified, a combination code can be used, and the combination codes are arranged in the following order from top to bottom.
D - Fiber optic ribbon structure
(Unsigned) - Loose tube fiber optic sheathing structure
J - Tight tube fiber optic sheathing structure
(Unsigned) - Stranded structure
G - Skeleton groove structure
X - Cable center tube (sheathing) structure
T - Ointment-filled structure
(Unsigned) - Dry water-blocking structure
R - Air-filled structure
C - Self-supporting structure
B - Flat shape
E - Elliptical shape
Z - Flame retardant
4) Sheath code:
Y – Polyethylene sheath
V – Polyvinyl chloride sheath
U – Polyurethane sheath
A – Aluminum-polyethylene bonded sheath (abbreviated as A sheath)
S – Steel-polyethylene bonded sheath (abbreviated as S sheath)
W – Steel-polyethylene bonded sheath with interlocking parallel steel wires (abbreviated as W sheath)
L – Aluminum sheath
G – Steel sheath
Q – Lead sheath
5) Designation of outer protective layer:
When there is an outer protective layer, it may include some or all of the padding layer, armor layer and outer coat. Its designation is represented by two sets of numbers (the padding layer does not need to be represented). The first set represents the armor layer, which can be one or two digits (see Table 2-13); the second set represents the outer coat or outer layer, which should be one digit (see Table 2-14).
Table 2-13: Cabin Categories
| Code | English Name |
|---|---|
| 0 | Suite |
| 2 | Mini Suite |
| 3 | Double Bed Ocean View |
| 33 | Twin Bed Ocean View |
| 4 | Double Bed Porthole |
| 44 | Twin Bed Porthole |
| 5 | Obstructed View |
Table 2-14: Outer Deck or Exterior
| Code | English Name |
|---|---|
| 1 | External Corridor |
| 2 | Promenade Deck |
| 3 | Deck of Boats |
| 4 | Deck of Boats with Lido |
| 5 | Deck of Boats with Protection |
The specifications
The specifications of a standard optical cable consist of the relevant specifications of the optical fiber and the conductive core wire.
1) The format of the optical cable specification is shown in Figure 2-28. The specifications of the optical fiber and the conductive core wire are separated by a cross sign ("+").
2) Optical fiber specifications: The specifications of an optical fiber consist of the number of fibers and the fiber type. If the same optical cable contains two or more specifications (number of fibers and type) of optical fibers, they are connected by a "+" sign.
① The fiber count designation uses the actual effective number of fibers of the same category in the optical cable.
② The fiber category designation should use the classification code for optical fiber products. According to standards such as IEC 60793-2 (1998) "Optical Fibers Part 2: Product Specifications," uppercase A represents multimode fiber, uppercase B represents single-mode fiber, and numbers and lowercase letters are used to represent different types of fiber. The classification codes for multimode and single-mode fibers are shown in the table below.
| Classification Code | Fiber Type | Fineness / μm | Denier / den | Material |
|---|---|---|---|---|
| Ala | Polyester staple fiber | 50 | 125 | PET |
| Alb | Polyester staple fiber | 62.5 | 125 | PET |
| Alc | Polyester staple fiber | 85 | 125 | PET |
| Ald | Polyester staple fiber | 100 | 140 | PET |
| A2a | Acrylic staple fiber | 100 | 140 | PAN (Acrylic) |
| Classification Code | Name (English) | Material |
|---|---|---|
| Bl.1 | Non-colored displacement | Silica |
| Bl.2 | Colored displacement | Silica |
| B2 | Colored displacement | Silica |
| B4 | Non-colored displacement | Silica |
3) Specifications of conductive core wires: The composition of conductive core wires shall comply with the provisions of relevant communication industry standards regarding the composition of copper core wires.
Example
Example 1: Outdoor optical cable for communication, featuring metal reinforcement, loose tube stranding, filled structure, aluminum-polyethylene bonded sheath, corrugated steel tape armor, and polyethylene sheath, comprising 12 50um/125um silica series graded-color multimode optical fibers and 5 four-wire groups of 0.9mm copper wire for remote power supply and monitoring. The cable model should be represented as GYTA5312Ala+4×0.9.
Example 2: Outdoor optical cable for communication, featuring metal reinforcement, fiber ribbon, loose tube stranding, filled structure, and aluminum-polyethylene bonded sheath, comprising 24 non-zero dispersion-shifted single-mode optical fibers. The cable model should be represented as GYDTA24B4.
Example 3: Indoor optical cable for communication, featuring non-metallic reinforcement, fiber ribbon, flat structure, and halogen-free flame-retardant polyethylene sheath, comprising 12 conventional or non-dispersion-shifted single-mode optical fibers. The cable model should be represented as GJFDBZY12B1.
Fiber optic cable end identification
To correctly perform splicing, measurement, and maintenance of optical cable projects, it is essential to first master the methods of identifying the cable's ends and arranging the fiber sequence within the cable. This is necessary to improve construction efficiency and facilitate future maintenance.
The fiber units within the optical cable, and the fibers within each unit, are identified using a full spectrum of colors to indicate the cable's ends and fiber sequence numbers. The color spectrum arrangement and the added marking colors vary slightly from country to country and are specified in the product standards of each nation. Currently, domestically produced optical cables fully meet engineering needs; therefore, this section will only introduce the most commonly used full spectrum optical cables.
The identification of fiber optic cables is somewhat similar to that of electrical cables.
1) For new optical cables: The red dot end is end A, and the green dot end is end B; the end with the smaller length number on the outer sheath is end A, and the other end is end B.
2) For old optical cables: Because they are old cables, the red and green dots and length numbers may not be visible (they may have been worn away during construction). The method of identification is: facing the end of the cable, if the loose tubes in the same layer are arranged clockwise in the order of blue, orange, green, brown, gray, and white, then it is end A of the cable; otherwise, it is end B.
Fiber ordering in communication optical cables
The unit loose tube optical fiber chromatograms in optical cables come in two types: one with 6 cores and the other with 12 cores. The chromatogram of the former is arranged in the order of blue, orange, green, brown, gray, and white, while that of the latter is arranged in the order of blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, and sky blue.
If it is a 6-core unit loose tube, then the 6 optical fibers in the blue loose tube (blue, orange, green, brown, gray, and white) correspond to optical fibers 1 to 6; the 6 optical fibers in the orange loose tube that is closely connected to the blue loose tube (blue, orange, green, brown, gray, and white) correspond to optical fibers 7 to 12, and so on, until all the optical fibers in all the loose tubes are arranged.
If it is a 12-core unit loose tube, then the 12 optical fibers in the blue loose tube (blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, sky blue) correspond to fibers 1 to 12; the 12 optical fibers in the orange loose tube adjacent to the blue loose tube (blue, orange, green, brown, gray, white, red, black, yellow, purple, pink, sky blue) correspond to fibers 12 to 24, and so on, until all the optical fibers in the loose tubes are arranged.
This process reveals a unified color spectrum for both optical and electrical cables, employing the 10 colors that constitute the insulation layer of the full-spectrum, all-plastic cable core: white, red, black, yellow, purple, blue, orange, green, brown, and gray. However, a key difference lies in the color cycle. In full-spectrum, all-plastic cables, the minimum color cycle is 5 colors (groups), such as white/blue, white/orange, white/green, white/brown, and white/gray. In optical cables, however, there are 6 colors-blue, orange, green, brown, gray, and white. Furthermore, each loose tube contains 6 optical fibers, not 5. This distinction is crucial to understand.
