Type of Splitters for FTTH

Type of Splitters for FTTH : In this article, I will discuss about fiber optic splitters that widely used in FTTH network. A lot of telecom site engineers have confusions about the type of splitters, I will try to remove all type of confusions through this article. We all know that the Optical splitters shall be used in exchanges, closures, equipment cabinets, boxes and main equipment rooms that house Optical Line Terminal Equipment and associated Fiber Management Systems. Also they shall be used in cabinets and boxes located in customer’s building where transmission equipment are provided.

Each optical splitter will be available as a unit or modular configuration, with or without pre-installed input and output connectors. Splitters shall be used to optically split power from optical fibers in passive optical network to multiple customer premises, operating in all wavelengths in the optical spectrum from 1260nm to 1650nm.

Type of Splitters for FTTH

Splitters for FTTH

Definition of Optical Splitters

Fiber optic splitter is passive optical devices that connect three or more fiber ends, dividing one or two input into two or more outputs. Various Optical Splitters configurations shall be made available, with split ratios (1: N or 2: N, where N is 2, 4, 8, 16 or 32) with different encapsulations for a wide range of applications.

Fused Biconic Tapered (FBT): An FBT coupler is a device that efficiently aligns the pairs of two adjacent fibers to light from one fiber to another, from which the buffer has been stripped, and later by heating and stretching them, the input taper, the output taper remains the fusion. Both sides of the coupling area.

Planar Lightwave Circuit (PLC): Planar Lightwave Circuit is a technology used in passive, fiber-optic component manufacturing. It uses semiconductor (i.e. integrated circuit) fabrication techniques, to build compact, fiber-optic devices, such as high-count splitters (e.g.1:32), resulting in devices that are smaller and more robust.

Technical Requirements for Optical Splitters

The Optical Splitters shall be made compatible with telecom industries FTTH optical network requirements, operation and maintenance standards and practices.

Optical splitters are a very delicate device so optical splitters shall be able to be efficiently handled and managed during installation, securing and storage.

All metallic parts of the Optical Splitters must be corrosion-proof and all polymeric parts shall have a flammability rating of V-0 to UL 94.

Test result data and individual characteristics shall be supplied with every Optical Splitter unit. The manufacturers shall be certified with ISO 9001:2008 for Quality Management Systems.

Type of Splitters used for FTTH Network

Two types of splitters are commonly used in FTTH networks-
1. Fused Biconic Tapered (FBT)
2. Planar Lightwave Circuit (PLC)

I have discussed about Fused Biconic Tapered (FBT) and Planar Lightwave Circuit (PLC)  above, now try to learn about its design.

1. Fused Biconic Tapered (FBT): It Shall be designed for 1:2, 1:4 & 2:4 configurations, with or without pre-terminated connectors. The fiber output ends for splitters with connectors shall be equipped with LC/APC type connectors.

Configuration of FBT Splitters

FBT Splitter

The type of fiber shall be based on ITU-T G.657A. Fused Biconic Tapered (FBT) Shall be used in Optical Splitter Frame (OSF) which located in the exchange or inside outdoor distribution enclosures.

Construction and color code

Stainless Steel round tube type casing for FBT Splitters

FBT Splitters 1:2, 1:4 & 2:4 - Dimensions (mm) - 50L x 3Dia.

FBT Splitters 1:2, 1:4 & 2:4 - Dimensions (mm) - 50L x 5W x 4H.

Marking & Identification: The splitter unit housing or casing shall be clearly marked and labeled with manufacturer and supplier’s logos or names to facilitate identification.

2. Planar Lightwave Circuit (PLC) : It Shall be designed to accommodate the following configurations, with or without pre-terminated connectors:

PLC Splitter

PLC Splitter 1:32 Configuration

Splitters Type- 1:2 , 1:4 , 2:4 , 1:8 , 2:8 , 1:16 , 2:16 , 1:32 , 2:32

Splitters with a split ratio of 1: 2, 1: 4 or 2: 4 and 1: 8 or 2: 8 will be used in an optical splitters frame (OSF) that is located in exchange or in a special outdoor closure.

Splitter with split ratio of 1:8 or 2:8, 1:16 or 2:16, & 1:32 or 2:32 shall be used in street cabinets, specialized outdoor closures or termination boxes located in customer’s building.

Fiber output ends for splitter with connector that must be equipped with LC / APC type connector. Splitters with split ratios of 1: 2, 2: 4, 2: 8, 2:16, and 2:32 are also available without connectors. The type of fiber shall be based on ITU-T G.657A.

Construction and color code

Stainless Steel box type casing for PLC Splitters available in below Dimensions- 

PLC Splitters type - 1:8, 2:8, 1:16 & 2:16 - Dimensions (mm) - 60L x 10W x 5H
PLC Splitters type - 1:32 & 2:32 - Dimensions (mm) - 60L x 20W x 6H.

The splitters unit housing must be a durable, weather resistant, flame retardant package or casing. All splitters inputs and output pigtails shall be discrete 0.9mm diameter tight buffered cords or loose tubes, with 50cm (min.) in lengths.

For splitters units without connectors (for FAT closures applications, etc.), inputs and output pigtails length shall be 100cm (min.) for splicing.

All splitters input pigtails may be red in color. All splitters output pigtails may be blue in color. Splitters pigtails, with or without connectors, shall be labeled with numbers for identification.

Marking & Identification : The splitter unit housing or casing shall be clearly marked and labeled with manufacturer and supplier’s logos or names to facilitate identification.

Material Properties of Splitters

The following properties should be found in the materials of optical splitters-

1. Temperature -Humidity Aging - 85°C / 85% for 14 days.

2. Temperature -Humidity Cycling - - 40°C to 75°C, 10% to 80% Humidity, 14 days

3. Temperature Effects on DWDM Components - -40°C to 85°C, 1 to 2°C per min., one cycle,

4. Water Immersion - 43°C in distilled water, PH5.5 for 168 hour

5. Vibration Test-Variable Frequencies - 10Hz to 2000Hz, 1.52mm max. amplitude, 3 axes, 2 hours per axis.

6. Thermal Shock Test - Liquid Thermal Shock test, 0 to 100°C.

7. High Temperature Storage (Dry Heat) - 85% for 2000 hours.

8. High Temperature Storage (Damp Heat) - 85°C /85% up to 2000 hours.

9. Low Temperature Storage - -40°C for 2000 hours.

10. Temperature Cycling Test - -40°C to 70°C air thermal shock, 10 cycles.

Optical Splitters Characteristics

The optical splitters shall meet with following characteristics-

1. Operating Wavelength - 1260 – 1650 nm

2. Operating Temp. Range - - 40°C to 85°C

3. Split Ratios (even) - 1:2,1:4,2:4,1:8,2:8,1:16,2:16,1:32,2:32

4. Insertion Loss (max, dB) - 3.6,7.2,7.8,10.5,11.2,13.8,14.6,16.9,17.5

5. Return Loss (min, dB) - 50

Optical Splitters Other Details

Optical Splitters : Each Optical Splitters shall be individually packed, placed in a box with complete description in English.

The individual Optical Splitters package may be multi-packed in a strong, weather resistance carton boxes, suitable for shipping, handling and storage.

Optical Splitters may be pre-assembled in other equipment such as FDT, and respective packing specification of the equipment shall apply.

Splitters Connector Protection : All Splitters Connectors (LC/APC) shall have protective end-caps or covers.

Marking details : Each individual package and multi-packed carton shall be marked in clear & legible color in English, on at least two sides of the package and the multi-packed carton box- Telecom company name, Name of Item, Unit and Package Quantity, Country of Origin, Manufactures Name or Trademark, Month and Year of Manufacture.

Last Word

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