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Two Important Methods for Fiber Optic Splicing

Fiber optic splicing is an important method of joining two fiber optic cables together. It is a preferred solution when an available fiber optic cable is not sufficiently long for the required run. Besides, splicing is designed to restore fiber optic cables when they are accidentally broken. Nowadays, fiber optic splicing is widely deployed in telecommunications, LAN (Local Area Network) and networking projects. Typically, fiber optic splices can be undertaken in two ways: fusion splices and mechanical splices. This paper firstly illustrates the specific process of fusion splicing method and mechanical splicing method, then makes a comparison of the two methods for your reference.

Fusion Splicing Method

Fusion splicing is a permanent connection of two or more optical fibers by welding them together using an electronic arc. It is the most widely used method of splicing as it provides for the lowest loss, less reflectance, strongest and most reliable joint between two fibers. When adopting this method, fusion splicing machines are often used. Generally, there are four basic steps in fusion splicing process as illustrating in following one by one.

Step 1: strip the fiber

The splicing process begins with the preparation for both fibers ends to be fused. So you need to strip all protective coating, jackets, tubes, strength members and so on, just leaving the bare fiber showing. It is noted that the cables should be clean.

Step 2: cleave the fiber

A good fiber cleaver is crucial to a successful fusion splice. The cleaver merely nicks the fiber and then pulls or flexes it to cause a clean break rather than cut the fiber. The cleave end-face should be perfectly flat and perpendicular to the axis of the fiber for a proper splice.

Step 3: fuse the fiber

When fusing the fiber, there are two important steps: aligning and melting. Fist of all, aligning the ends of the fiber within the fiber optic splicer. Once proper alignment is achieved, utilizing an electrical arc to melt the fibers to permanently welding the two fiber ends together.

Step 4: protect the fiber

A typical fusion splice has a tensile strength between 0.5 and 1.5 lbs and it is not easy to break during normal handling. However, it still requires protection from excessive bending and pulling forces. By using heat shrink tubing, silicone gel and/or mechanical crimp protectors will keep the splice protected from outside elements and breakage.

Mechanical Splicing Method

If you want the splices to be made quickly and easily, the mechanical splice is a better choice. A mechanical splice is a junction of two or more optical fibers that are aligned and held in place by a self-contained assembly. A typical example of this method is the use of connectors to link fibers. This method is most popular for fast, temporary restoration or for splicing multimode fibers in a premises installation. Like fusion splice, there are also four basic steps in mechanical splice.

Step 1: strip the fiber

Fiber preparation here is practically the same as for fusion splicing. Just removing the protective coatings, jackets, tubes, strength members to show the bare fiber. Then ensuring the cleanliness of the fiber.

Step 2: cleave the fiber

The process is the same as the cleaving for fusion splicing. It is necessary to obtain a cut on the fiber which is exactly at right angles to the axis of the fiber.

Step 3: mechanically join the fiber

In this step, heating is not used as in fusion splice. Simply connecting the fiber ends together inside the mechanical splice unit. The index matching gel inside the mechanical splice apparatus will help couple the light from one fiber end to the other.

Step 4: protect the fiber

Once fibers are spliced, they will be placed in a splice tray which is then placed in a splice closure. Outside plant closures without use of heat shrink tubing will be carefully sealed to prevent moisture damage to the splices.

Which Method is Better?

Both fusion splicing and mechanical splicing method have their advantages and disadvantages. Whether choosing fusion splice or mechanical splice depends on the applications.

The fusion one provides a lower level of loss and a higher degree of permanence than mechanical splicing. However, this method requires the use of the expensive fusion splicing equipment. In view of this, fusion splice tends to be used for the long high data rate lines that are installed that are unlikely to be changed once installed.

The mechanical splicing is used for applications where splices need to be made very quickly and where the expensive equipment for fusion splices may not be available. Some mechanical fiber optic splice easily allows both connection and disconnection. In this way, a mechanical splice may be used in applications where the splice may be less permanent.

are share from: http://www.fiber-optic-solutions.com/two-important-methods-for-fiber-optic-splicing.html

Test Method Fiber Optic

Choose a Test Method.

Once the test cords are verified, you may test the fiber link. There are three options for setting an optical reference between a source and power meter. These options may use 1, 2 or 3 jumpers, or Test Reference Cords. The method used is determined by your regional or vendor-specific requirements. A couple of things should be noted. Optical Loss Test Sets (OLTS) typically have a source and meter at EACH end so they measure two fibers at one time. For simplicity and clarity the graphics here are only showing a simplex setup – one light source to one power meter (except in testing setup with 2 reference cords, that shows both links). When the term “test reference cord” is shown this means a cord with “reference grade connectors”. These are connectors that provide much lower loss than “standard” connectors. Test reference jumpers are more expensive than regular patch cords. A couple of final notes on referencing: Regardless of vendor or model, all optical sources should be allowed to warm up for about 5 minutes prior to performing a reference. On most Optical Loss Test Sets designed for Tier 1 certification, there will be a setting for “reference method”. The physical configuration used to perform the reference MUST match the setting on the test device or your test margins are invalid. So if you set your test setup to do a three fiber reference but what you actually physically do is a one fiber reference, you have a completely invalid test result, especially your test margins are going to be completely invalid. NEVER disconnect the test jumper from the transmitter after a reference is performed – this will destroy the reference – you will need to do it again. Always check your reference by connecting the source test jumper to the power meter test jumper and perform a measurement. There is some variation in what you would expect to see when checking your reference – based on the quality of your test jumpers and the reference method used, certainly below 0.3 dB. One thing you want to watch for when checking your reference is ‘gainers’ – where your test set shows a loss with a positive value, +0.2 dB for example. That is also an indication that you’ve got a bad reference and you’ll need to redo your reference. It is a good practice to save your reference check to have proof that a good reference was established prior to testing. If during the course of testing you question your results, simply check your reference again and re-reference if needed, save the result and carry on testing.
referenece: commscope SP3802 training

Network Cabling Site Survey Check List

1 Information sources
Information for this document can be collected from the following sources:
· Customer’s representative
· Site survey
· Available documents and architectural drawings (see below)
· Local authorities, having jurisdiction
· Other subcontractors
2 Recommendations
· Never believe or assume, always check
· Collect all data from the customer in written form
· Use the latest version of your vendor’s Design Manual
· Use BICSI TDMM manual
· Use cabling standards

3 Customer Documentation
Request that the customer provides all or some of the following documents and drawings:
· Site plan
· Floor plans
· Elevation plans
· Roof plans
· Reflected ceiling plans with light fixture locations
· Power plans with possible EMI sources
· Outlet location plans
· Mechanical plan with HVAC duct locations
· Sprinkler plan with sprinkler pipe locations
3.1.1.1 Site plan
· Is it available?
· Does it contain property lines, building outlines, water and gas pipe lines, power lines
(aerial/buried/underground), trees, roads, other obstacles?

4 Applications Considerations
4.1.1 Horizontal Applications
· What services are to be provided to work areas (voice, data, video, other)?
· What are the requirements of each service per work area (number of copper pairs per
application, number of fibers per application)?
4.1.2 Intrabuilding Backbone Applications
· What services are to be supported by the backbone cabling (voice, data, video, other)?
· What are the requirements of each service (number of copper pairs per application,
number of fibers per application)?
4.1.3 Campus Applications
· What services are to be supported by the backbone cabling (voice, data, video, other)?
· What are the requirements of each service (number of copper pairs per application,
number of fibers per application)?

5 Architectural Considerations
· Equipment Room (ER)
· Telecommunications Closets (TC)
· Backbone Pathways
· Horizontal Pathways
· Entrance Facility
· Grounding and Bonding System
5.1 Equipment Room
5.1.1 Location
· Identify desirable ER location of the equipment room on the site plan
Size
· Height and width
· Usable floor space
· Usable wall space
· Ceiling height
· Power feeder location
5.1.2 Served Systems
· What equipment is to be placed in the equipment room?
· Identify type, size, weight and manufacturer’s installation requirements
5.1.2.1 Mounting of Connecting Hardware
· Identify the preferred method of mounting the connecting hardware (wall-mount, rackmount,
cabinets)
5.1.2.2 Mounting of Active Equipment
· Identify the preferred method of mounting the active equipment (wall-mount, rack-mount,
cabinets)
5.1.3 Approved Grounding
· Is it available?
· Mark location on the site plan
5.1.4 Means of bringing in heavy equipment available?
· Elevator rating
· Elevator door size
5.1.5 Floor-loading capacity
· Check that floor-loading capacity is adequate for heavy equipment which will be placed in
the equipment room.

5.1.6 Climate control system
· Is it available?
· What type (dedicated/non-dedicated)?
· Humidity control available?
· Temperature control available?
· Dust and contaminant control available?
· Is climate control system operation continuous?
5.1.7 Fire-extinguishing system
· Is it available?
· What type?
· Fire extinguishers available?
· If needed, consult local fire inspector
5.1.8 Firestopping
· Locate fire barriers, check their ratings
· Locate possible penetrations in fire barriers that may require firestopping
· If needed, consult local fire inspector
5.1.9 Lighting system
· Is it available?
· What capacity?
· Is it adequate?
· Is emergency lighting needed?
5.1.10 Possible EMI sources
· Location
· Type
· Mark EMI sources on the site plan
5.1.10.1 Possible hazards
· Locate any sources of water flooding, seepage, steam, heat, corrosive atmosphere
· Mark them on site plan
· Is the equipment room located above any threat of flooding?
5.1.11 Electric Power
· Number and location (mark on the equipment room plan)
· Is it adequate?
· Is power quality adequate for operating electronic equipment?
· Is emergency power system available?
· If needed, consult the electric power subcontractor
5.1.12 Plywood wall covering
· Is it available (in case of wall-mounting)?
· Is it void-free and fire-rated or coated with at least two coats of fire-resistant paint?
· How reliable is its mounting?

5.1.13 Access and proximity to entrance facility
· Locate entrance facility and determine distance and available pathways to the equipment
room
· Mark entrance facility location on the floor plan
5.1.14 Access to Backbone Pathways
· Identify and mark the location and size of backbone pathways on the equipment room plan
5.1.15 Space for internal cable pathways inside equipment room
· Is it available?
· What are customer preferences (cable trays, access floor)?
5.1.16 Dust and Static Electricity
· The floor surface must not produce dust and static electricity.
· What type of floor surface is present?
· Is it adequate?
5.1.17 Doors
· Is the door fully-opening or removable?
· Is the door lockable?
· What size (width, height)?
The size must be appropriate for bringing in the hardware and equipment.
5.1.18 Security
· What security means are available?
· What are customer requirements?
· Does any other building service pretend to share ER?

5.2 Telecommunication Closet
This step must be repeated for every telecommunications closet in the building.
5.2.1 Type and Location
· Identify and discuss possible location of the telecommunications closet on the floor plan
· Identify and discuss its type (cabinet/shallow closer/enclosed closet)
· Check if the telecommunications closet is accessible from a hallway or other common area
5.2.2 Floor Space Served
· Identify the usable floor space served by the telecommunications closet
· Identify the work areas served by the telecommunications closet
Size
· Length and width
· Usable floor space
· Usable wall space
· Ceiling height
5.2.3 Access to Backbone Pathways
· Identify and mark the location and size of backbone pathways on the telecommunications
closet plan
5.2.3.1 Mounting of Connecting Hardware
· Identify the preferred method of mounting the connecting hardware (wall-mount, rackmount,
cabinets)
5.2.3.2 Mounting of Active Equipment
· Identify the preferred method of mounting the active equipment (wall-mount, rack-mount,
cabinets)
5.2.4 Sharing with other services
· Check if equipment/hardware not related to the telecommunications and its support is
located or pass through the telecommunications closet. The telecommunications closet
may not be shared with services that interfere with telecommunications services.
5.2.5 Horizontal cable length
· Check if location of TC is within the limit of the allowed horizontal cable length
5.2.6 Doors
· Is the door fully-opening or removable?
· Is the door lockable?
· What size (width, height)?
The door size must be appropriate for bringing in the hardware and equipment.
5.2.7 Dust and Static Electricity
· The floor surface must not produce dust and static electricity.
· What type of floor surface is present?
5.2.7.1 Served Systems
· Will the telecommunications closet contain active equipment?
5.2.8 Floor-loading capacity
· Check that floor-loading capacity is adequate.
5.2.9 Future expansions
· Determine customer’s future expansion needs

5.3 Backbone Pathways
· Is it available?
· What type ? (sleeve, slot, conduit, cable racks)
· What size and quantity?
· Location?
· What is the total floor space served by backbone pathways?
· Are vertical shafts available?
· Are they vertically aligned?
· Are they connected to Equipment Rooms and Telecommunications Closets?
· What size and location ?
5.3.1 Firestopping
· Locate building fire barriers and check its ratings.

5.4 Horizontal Pathways
· Are they available?
· What type and size?
· If present, check the fill ratio. What cable is already placed in the pathways?
· Customer preferences?
· Determine the location of EMI sources in spatial relation to the horizontal pathways
· Determine the location of HVAC pathways in spatial relation to the horizontal pathways
· Determine the location of sprinkler pipes in spatial relation to the horizontal pathways
· Check side and top clearances of installed pathways

5.5 Entrance Facility
· Mark location on the floor plan
· Type (underground, buried, aerial)
· Locate the equipment room and determine distance and available pathways to the
entrance facility
· Check if a grounding busbar in the close proximity to entrance facility is available

5.6 Grounding and Bonding System
· Is a separate telecommunications grounding and bonding system available?
· If yes, is it compliant to TIA 607?

6 Horizontal Cabling Subsystem
This step must be repeated for each floor/Telecommunications Closet
· Determine usable floor space
· Determine number and location of Work Areas (mark on the site plan)
· Determine number, type (copper, fiber) and mounting of Telecommunications Outlets per
work area (mark on the site plan)
· Determine needed type of horizontal cable (copper, fiber)
· Determine cabling method (home-run, zone wiring)
· Mark the location of serving Telecommunications Closet

7 Building Backbone Cabling Subsystem
This step must be repeated for each Telecommunications Closet and for each type of backbone
cabling (copper voice; copper data; fiber data).
· Backbone cabling type (copper, fiber)
For copper cable: performance category, total number of pairs, number of pairs per cable
and number of cables
For fiber cable: total fiber count, type (multimode/single-mode), number of fibers per cable
and number of cables
· Number of work areas served by backbone
· Backbone redundancy needed?
· Backbone cabling pathways (see “Architectural Considerations”). Are they adequate?