Ribbon fiber knowledge explanation

ribbon fiber

Ribbon optical fiber improves the efficiency of connector assembly and facilitates multi-core fusion, thereby improving work efficiency.

Ribbon fibers consist of 4, 8, or 12 fibers of different colors, with up to 1,000 core fibers. The fiber surface is coated with UV-curable acrylic material, which can be easily removed using standard fiber stripping pliers for multi-core fusion or single fiber removal. Using a multi-core fusion splicer, the ribbon fiber can be fused at one time, and can be easily identified in the optical cable with a large number of fibers.

Fiber Type

The following is a description of the most commonly used types of communication fibers.

MMF (Multimode Fiber)

- OM1 fiber or multimode fiber (62.5/125)

- OM2/OM3 fiber (G.651 fiber or multimode fiber (50/125))

SMF (Single Mode Fiber)

- G.652 (dispersion non-shifted single mode fiber)

- G.653 (Dispersion Shifted Fiber)

- G.654 (cutoff wavelength shifted fiber)

- G.655 (Non-Zero Dispersion Shifted Fiber)

- G.656 (Low Slope Non-Zero Dispersion Shifted Fiber)

- G.657 (bend resistant fiber)

Technically, any suitable fiber can be used in FTTx technology as long as the optical budget allows, but the most commonly used fibers for FTTx technology are G.652 and G.657.

G.651 (multimode fiber)

G.651 is mainly used in local area networks and is not suitable for long-distance transmission, but in the range of 300 to 500 meters, G.651 is a low-cost multimode transmission fiber.

ITU-T G.651 fiber is OM2/OM3 fiber or multimode fiber (50/125). There is no OM1 fiber or multimode light (62.5/125) in the ITU-T recommended fiber.

The reflectivity of the multimode fiber (50/125) core changes gradually from the center to the cladding, allowing multiple optical transmissions at the same speed.

G.652 fiber (dispersion non-shifted single mode fiber)

The most common single-mode fiber in the world. Signal-distorting dispersion at wavelengths around 1,310 nm can be minimized. You can use the 1550nm wavelength working window for short distance transmission or with dispersion compensating fiber or with modules.

G.652A/B are basic single-mode fibers, and G.652C/D are low-water peak single-mode fibers

G.653 (Dispersion Shifted Fiber)

This fiber minimizes chromatic dispersion at wavelengths around 1,550nm, thereby minimizing light loss.

G.654 (cutoff wavelength shifted fiber)

The official name of G.654 is cutoff wavelength shifted fiber, but it is commonly referred to as low attenuation fiber. The characteristics of low attenuation make G.654 fiber mainly used for long-distance transmission on the seabed or on the ground, such as 400 kilometers of lines without transponders.

G.655 (Non-Zero Dispersion Shifted Fiber)

G.653 fiber has zero dispersion at 1,550nm wavelength, while G.655 fiber has concentrated or positive or negative dispersion, which reduces the adverse effects of nonlinear phenomena that interfere with adjacent wavelengths in DWDM systems.

First-generation non-zero dispersion-shifted fibers, such as PureMetro® fibers, have the advantage of having a dispersion of 5ps/nm or less per kilometer, making dispersion compensation easier. Second-generation non-zero dispersion-shifted fibers such as PureGuide® have a dispersion of around 10ps/nm per kilometer, doubling the capacity of DWDM systems.

G.656 fiber (low-slope non-zero dispersion-shifted fiber)

A type of non-zero dispersion-shifted fiber, which has strict requirements for the speed of dispersion, ensuring transmission performance in a larger wavelength range in DWDM systems.

G.657 (bend resistant fiber)

The newest member of the ITU-T fiber optic family. New products based on the needs of FTTx technology and assembly applications.

G.657A fiber is compatible with G.652 fiber, and G.657B fiber does not need to be compatible with traditional single-mode fiber in connection.

Classification of Fiber Optic Wiring Technology

Optical fiber wiring technology can be divided into fusion splicing, mechanical splicing and connector wiring. Fusion and mechanical splicing are permanent wiring, while connector wiring can be repeatedly disassembled. Optical connector wiring is mainly used for wiring points that must be switched in the operation and maintenance of optical services, and permanent wiring is mainly used in other places.

The principle of loss in fiber optic wiring

Fiber splices must be positioned so that the portions of the core through which the light passes are opposed and correctly positioned.

The wiring loss of optical fiber is mainly caused by the following reasons.

(1) Axis offset

Optical axis offsets between connecting fibers can cause wiring losses. In the case of general-purpose single-mode fiber, the splice loss is approximately the value of the square of the axis offset multiplied by 0.2. (For example, when the wavelength of the light source is 1310 nm and the axis offset is 1 μm, the wiring loss is about 0.2 dB)

(2) Angular offset

The angular shift between the optical axes of the connecting fibers can cause wiring losses. For example, if the angle of the section cut with a fiber cleaver before fusion splicing increases, the fiber will be wired in an inclined state, so care must be taken.

(3) Gap

Gaps between fiber end faces can cause wiring loss. For example, if the fiber end faces connected by mechanical splices are not properly seated, splicing losses can result.

(4) Reflection

When there is a gap on the end face of the fiber, due to the difference in refractive index between the fiber and the air, the wiring loss will be caused by the reflection of a maximum of 0.6dB. Also, it is important to clean the fiber end face of the optical connector in order to prevent light breakage. However, if there is dust on the end face of the optical connector other than the end face of the optical fiber, loss will also occur, so it is important to clean all the end faces of the optical connector.

Types and principles of fusion

Fusion splicing is a wiring technology that uses the heat generated by the discharge between the electrode rods to melt the optical fibers into one. Fusion methods are divided into the following two categories.

(1) Fiber core adjustment method

This is a fusion method in which the core wire of the optical fiber is observed under a microscope, positioned by image processing, and the central axis of the core wire is aligned, and then electric discharge is performed. Positioning is performed from both directions using a fusion splicer equipped with a two-way viewing camera.

(2) Fixed V-groove alignment method

This is a fusion splicing method that uses high-precision V-groove arrangement of optical fibers, and uses the core-adjusting effect generated by the surface tension when melting the optical fibers to adjust the outer diameter of the core. Recently, due to the development of manufacturing technology, the dimensional accuracy of the optical fiber core position and the like has been improved, so that low-loss wiring can be realized. This method is mainly used for multi-core one-time wiring.

Precautions for fusion work

This is a fusion splicing method that uses high-precision V-groove arrangement of optical fibers, and uses the core-adjusting effect generated by the surface tension when melting the optical fibers to adjust the outer diameter of the core. Recently, due to the development of manufacturing technology, the dimensional accuracy of the optical fiber core position and the like has been improved, so that low-loss wiring can be realized. This method is mainly used for multi-core one-time wiring.

According to the transmission mode of light in the optical fiber, the optical fiber can be divided into two types: single-mode optical fiber and multi-mode optical fiber.

Single-mode fiber (Single-mode Fiber): Generally, the fiber jumper is shown in yellow, and the connector and protective sleeve are in blue; the transmission distance is longer.

Multi-mode fiber (Multi-mode Fiber): Generally, the fiber patch cord is indicated in orange, and some are indicated in gray, and the connector and protective sleeve are in beige or black; the transmission distance is short.

Multimode fiber (MMF, Multi Mode Fiber) has a thicker core and can transmit light in multiple modes. However, the intermodal dispersion is relatively large, and the intermodal dispersion will gradually increase with the increase of the transmission distance. The transmission distance of multimode fiber is also related to its transmission rate, core diameter, and mode bandwidth.

Single-mode fiber (SMF, Single Mode Fiber) has a thin core and can only transmit light in one mode. Therefore, its intermodal dispersion is very small, which is suitable for long-distance communication.

Fiber diameter

The fiber diameter generally adopts the expression method of core diameter/cladding diameter, and the unit is μm. For example: 9/125μm means that the diameter of the fiber center core is 9μm, and the diameter of the fiber cladding is 125μm.

Note on the use of optical fibers:

The transceiver wavelengths of the optical modules at both ends of the fiber jumper must be the same, that is to say, the two ends of the optical fiber must be optical modules with the same wavelength. R> In general, the short-wave optical module uses multi-mode fiber (orange fiber), and the long-wave optical module uses single-mode fiber (yellow fiber) to ensure the accuracy of data transmission.

Do not bend and loop the optical fiber excessively during use, which will increase the attenuation of light during transmission.

After using the optical fiber jumper, it is necessary to protect the optical fiber connector with a protective sleeve. Dust and oil will damage the coupling of the optical fiber.

Optical fiber connectors can be divided into common silicon-based optical fiber single-mode and multi-mode connectors according to different transmission media, and other optical fiber connectors such as plastic as the transmission medium; according to the structure of the connector, it can be divided into: FC , SC, ST, LC, D4, DIN, MU, MT, etc. Among them, ST connectors are usually used for wiring equipment, such as fiber distribution frames, fiber modules, etc.; while SC and MT connectors are usually used for network equipment. According to the shape of the fiber end face, there are FC, PC (including SPC or UPC) and APC; according to the number of fiber cores, there are single-core and multi-core (such as MT-RJ) points.