The Era of Fusion Splicing Is Coming

by Fiber-MART.COM

As fiber deployment has become mainstream, splicing has naturally crossed from the outside plant (OSP) world into the enterprise and even the data center environment. Fusion splicing involves the use of localized heat to melt together or fuse the ends of two optical fibers. The preparation process involves removing the protective coating from each fiber, precise cleaving, and inspection of the fiber end-faces. Fusion splicing has been around for several decades, and it’s a trusted method for permanently fusing together the ends of two optical fibers to realize a specific length or to repair a broken fiber link. However, due to the high costs of fusion splicers, it has not been actively used by many people. But these years some improvements in optical technology have been changing this status. Besides, the continued demand for increased bandwidth also spread the application of fusion splicing.

 

New Price of Fusion Splicers

Fusion splicers costs have been one of the biggest obstacles to a broad adoption of fusion splicing. In recent years, significant decreases in splicer prices has accelerated the popularity of fusion splicing. Today’s fusion splicers range in cost from $7,000 to $40,000. The highest-priced units are designed for specialty optical fibers, such as polarization-maintaining fibers used in the production of high-end non-electrical sensors. The lower-end fusion splicers, in the $7,000 to $10,000 range, are primarily single-fiber fixed V-groove type devices. The popular core alignment splicers range between $17,000 and $19,000, well below the $30,000 price of 20 years ago. The prices have dropped dramatically due to more efficient manufacturing, and volume is up because fiber is no longer a voodoo science and more people are working in that arena. Recently, more and more fiber being deployed closer to the customer premise with higher splice-loss budgets, which results in a greater participation of customers who are purchasing lower-end splicers to accomplish their jobs.

 

More Cost-effective Cable Solutions

The first and primary use of splicing in the telecommunications industry is to link fibers together in underground or aerial outside-plant fiber installations. It used to be very common to do fusion splicing at the building entrance to transition from outdoor-rated to indoor-rated cable, because the NEC (National Electrical Code) specifies that outdoor-rated cable can only come 50 feet into a building due to its flame rating. The advent of plenum-rated indoor/outdoor cable has driven that transition splicing to a minimum. But that’s not to say that fusion splicing in the premise isn’t going on.

 

Longer distances in the outside plant could mean that sticking with standard outdoor-rated cable and fusion splicing at the building entrance could be the more economical choice. If it’s a short run between building A and B, it makes sense to use newer indoor/outdoor cable and come right into the crossconnect. However, because indoor/outdoor cables are generally more expensive, if it’s a longer run with lower fiber counts between buildings, it could ultimately be cheaper to buy outdoor-rated cable and fusion splice to transition to indoor-rated cable, even with the additional cost of splice materials and housing.

 

As fiber to the home (FTTH) applications continue to grow around the globe, it is another situation that may call for fusion splicing. If you want to achieve longer distance in a FTTH application, you have to either fusion splice or do an interconnect. However, an interconnect can introduce 0.75dB of loss while the fusion splice is typically less than 0.02dB. Therefore, the easiest way to minimize the amount of loss on a FTTH circuit is to bring the individual fibers from each workstation back to the closet and then splice to a higher-fiber-count cable. This approach also enables centralizing electronics for more efficient port utilization. In FTTH applications, fusion splicing is now being used to install connectors for customer drop cables using new splice-on connector technology and drop cable fusion splicer.

 

FTTH drop cable fusion splicer

 

A Popular Option for Data Centers

A significant increase in the number of applications supported by data centers has resulted in more cables and connections than ever, making available space a foremost concern. As a result, higher-density solutions like MTP/MPO connectors and multi-fiber cables that take up less pathway space than running individual duplex cables become more popular.

 

Since few manufacturers offer field-installable MTP/MPO connectors, many data center managers are selecting either multi-fiber trunk cables with MTP/MPOs factory-terminated on each end, or fusion splicing to pre-terminated MTP/MPO or multi-fiber LC pigtails. When you select trunk cables with connectors on each end, data center managers often specify lengths a little bit longer because they can’t always predict exact distances between equipment and they don’t want to be short. However, they then have to deal with excess slack. When there are thousands of connections, that slack can create a lot of congestion and limit proper air flow and cooling. One alternative is to purchase a multi-fiber pigtail and then splice to a multi-fiber cable.

 

Inside the data center and in the enterprise LAN, 12-fiber MPO connectors provide a convenient method to support higher 40G and 100G bandwidth. Instead of fusing one fiber at a time, another type of fusion splicing which is called ribbon/mass fusion splicing is used. Ribbon/mass fusion splicing can fuse up to all 12 fibers in one ribbon at once, which offers the opportunity to significantly reduce termination labor by up to 75% with only a modest increase in tooling cost. Many of today’s cables with high fiber count involve subunits of 12 fibers each that can be quickly ribbonized. Splicing those fibers individually is very time consuming, however, ribbon/mass fusion splicers splice entire ribbons simultaneously. Ribbon/mass fusion splicer technology has been around for decades and now is available in handheld models.

 

Conclusion

Fusion splicing provides permanent low-loss connections that are performed quickly and easily, which are definite advantages over competing technologies. In addition, current fusion splicers are designed to provide enhanced features and high-quality performance, and be very affordable at the same time. Fiberstore provides various types and uses of fusion splicers with high quality and low price. For more information, please feel free to contact us at sales@fiber-mart.com.

Differences Between PLC Splitters and FBT Coupler

by Fiber-MART.COM

FBT Coupler and PLC splitter Tech

 

PLC Splitter

 

Planar Lightwave Circuit (PLC) splitter, PLC splitters are used to distribute or combine optical signals. It is based on planar lightwave circuit technology and provides a low cost light distribution solution with small form factor and high reliability. Planar lightwave circuit (PLC) splitter is a type of optical power management device that is fabricated using silica optical waveguide technology to distribute optical signals from Central Office (CO) to multiple premise locations.

 

FBT Coupler

 

Fused biconical taper,this is traditional technology to weld several fiber together from side of the fiber.

 

2. Comparison between FBT and PLC.

 

PLC splitter

 

SpliSplit Ratio (Max): 1*64 splits

Eveness: Can split light evenly

Size: Compact size

 

FBT coupler

 

Split Ratio: 1*8 splits

Eveness: Eveness is not very precise

Size: Big size for multi splits

 

TDL (Temperature Dependent loss)

 

Due to the manufacturing process and to the sensitivity of the fused region and of the splices integrated in the device, Fused coupler manufacturers have to specify also the TDL value. for a 1×2 Fused coupler, a typical value is +/10.15dB for a temperature range from -5 to +75 centigrade . At the first sight, it could look good, but we have here again to take into account the cascading effect. To make the comparison with 1×8 PLC splitter we have to multiply 0.15 by 3 (3 1×2 for each arm) to finally obtain 0.45dB.

 

PLC splitter works from -40 to 85 centigrade with a typical TDL of out +/- 0.25dB (-5 to 75 centigrade:+/-0.15dB)

 

Please note that this TDL effect is already included in the Max. insertion loss specifications available on data sheets.

 

PDL (Polarization dependent loss)

 

An lon-exchange PLC splitter shows a PDL much less than 0.2 dB independently from the split-ratio. A 1×2 fused coupler PDL ranges from 0.1 to 0.15dB.Also in this case, we have to cascade discrete 1*2 Fused coupler to obtain the desired split-ratio, Then also PDL will be increased.

 

A 1×8 fused coupler will show up to 0.45dB PDL, what is more than the double of a 1×8 PLC splitter.

 

Reliability

 

As previously explained, to fabricate  1×8 fused coupler, you need 7discrete 1×2 couplers and 6 splices. The risk of failure of a device, normally calculated by parameter called FIT(failure in time), is typically low for a single 1×2 fused coupler, but in the case of a 1×8 fuse fused coupler ,it has to be at lease multiplied by 7 and in addition to add the risk associated to the massive presence of splices in the circuits. As everybody knows, a splice is a potential failure point in a system to be minimized a s much as possible.At the contrary, a PLC splitter knows only 2 critical  points: input and output

 

People take advantage of fiber optic splitter that will send or simply combine optical signals in a good many products, which include FTTH solution, or anything else. Once in a while contain a challenge: Will certainly Make the most of PLC Splitter or FBT Coupler?

 

When you undertake compare, came across undertake compare meant for tools within the same exact split-ratio.

 

The figure 1 shows the insertion loss plot of a standard 1×8 PLC splitter from 1250 to 1650 nm. You can observe the maximum insertion loss including the water-peak in E band region(1360 to 1460 nm) and also the excellent uniformity out of this plot.

 

Typical value is 9.8dB for insertion loss and 0.5dB for uniformity.

 

A 1×2 fused coupler insertion loss plot is showed in the figure 2.if you analyze the operating wavelength range from 1250 to 1650 nm as for PLC splitter you will still find an overall good performance level. But that’s a single 1×2 fused coupler, so you are not comparing the same devices.

 

The 3rd plot represents the insertion loss spectral behavior for 1×8 fused coupler. To fabricate a 1×8 fused coupler device each arm have to be manufactured using 3 cascaded (spliced) 1×2 couplers. it means that the “worst” arm could show 10.8dB insertion loss max and the uniformity will be 3dB.

Optical Fiber Core

The core of a conventional optical fiber is a cylinder of glass or plastic that runs along the fiber’s length. The core is surrounded by a medium with a lower index of refraction, typically a cladding of a different glass, or plastic. Light travelling in the core reflects from the core-cladding boundary due to total internal reflection, as long as the angle between the light and the boundary is less than the critical angle. As a result, the fiber transmits all rays that enter the fiber with a sufficiently small angle to the fiber’s axis. The limiting angle is called the acceptance angle, and the rays that are confined by the core/cladding boundary are called guided rays.

 

The core is characterized by its diameter or cross-sectional area. In most cases the core’s cross-section should be circular, but the diameter is more rigorously defined as the average of the diameters of the smallest circle that can be circumscribed about the core-cladding boundary, and the largest circle that can be inscribed within the core-cladding boundary. This allows for deviations from circularity due to manufacturing variation.

 

Another commonly quoted statistic for core size is the mode field diameter. This is the diameter at which the intensity of light in the fiber falls to some specified fraction of maximum (usually 1/e2 ≈ 13.5%). For single-mode fiber, the mode field diameter is larger than the physical diameter of the core, because the light penetrates slightly into the cladding as an evanescent wave.

 

The three most common core sizes are:

 

9 µm diameter (single-mode)

50 µm diameter (multi-mode)

62.5 µm diameter (multi-mode)

PLC integrated automatic fiber tools fiber tester

Optical device module fiber testers automation instrument and system provider recently released PLC integrated automatic fiber tools fiber tester system. Compared with the early release of PLC system, the system is more comprehensive, 

including both the insertion loss, PDL, channel, uniformity index, at the same time, the system adopts the unique “reception” balance technology, can solve the problem of return loss index accuracy of stability test, the return loss 

 

test uncertainty to < 1 db @ – 60 db.

 

With the deepening of the FTTH patch cables industry promotion, PLC device/module automatic high precision testing requirements. How to reduce the end-to-end production test cost, improve fiber tester efficiency and resist the ability of 

 

the orders surge hit, has become the focus of competition of the enterprises, forcing enterprises to consider from the Angle of industry transformation equipment with the test solution upgrade, thus win the market competition. PLC integrated automatic testing system meets the requirements of production enterprises.

This system can automatically identify memory reference channel, a key to achieve all metrics automatic testing, through the PC software can realize index test, unqualified data, alarm, automatic storage, automatic generation of fiber tools reports and print output, and other functions. Compared with the traditional fiber tester pattern, the efficiency increased 4 times, and greatly reduce the test personnel