Tag Archives: PON

Comparison Between FBT and PLC Splitters

Enabling a single fiber interface to be shared among many subscribers, fiber optic splitters play an increasingly significant role in many of today’s optical networks. From FTTx systems to traditional optical networks, splitters provide capabilities that help users maximize the functionality of optical network circuits. In this article, I’d like to give a short introduction of fiber optic splitters.

Overview of FBT and PLC Splitters

In simple terms, a fiber optical splitter is a passive optical device that can split, or separate beams into two or more light beams. Based on the configuration of the splitter, these beams may or may not have the equal optical power as the original beam. By means of different constructions, the outputs of a splitter can have varying degrees of throughput, which is highly beneficial when designing optical networks.

fiber optic splitter

Now although technology continually evolves, and there are a variety of existing splitters in the market, the most two common types of fiber optic splitter are: fused biconic tapered splitter (FBT Splitter) and planar lightwave circuit splitter (PLC Splitter).

FBT is the traditional technology in which two fibers are placed closely together and fused together by applying heat while the assembly is being elongated and tapered. As the technology continues developing, the quality of FBT splitter is very good and they can be applied in a cost-effective way. Now FBT is designed to split power in optical telecommunication and widely used in passive networks, especially where the split configuration is relatively small.

FBT splitter.jpg

PLC splitter is a better choice for application where large split configurations are required. It uses an optical splitter chip to divide the incoming signal into multiple outputs. PLC splitter composes of three layers: a substrate, a waveguide, and a lid. The waveguide plays a key role in the splittering process which allows for passing specific percentages of light. Therefore, PLC splitters offer very accurate splits and a low loss. What’s more, PLC splitters have several types such as bare PLC splitter, blockless PLC splitters, fanout PLC splitter, mini-plug in type PLC splitter, etc.

PLC splitter.jpg

With the growth of FTTx worldwide, in order to serve mass subscribers, the demand for large split configurations in these networks has also grown quickly. Because of the performance benefits and overall low cost, PLC splitters are now the better solutions for these types of applications.

FBT Splitter vs. PLC Splitter

In optical networks, signals need to be splitted somewhere in order to serve for different customers. Splitter technology has made great progress in the past few years by introducing PLC splitter. However, being similar in size and outer appearance, the two types of splitter still have many differences. Here is a brief comparison of them.

Materials

FBT splitter is made out of materials that are easily available, for example, steel, fiber, hot dorm and others. All of these materials are cheap, which determines the low cost of the device itself. The technology of the device manufacturing is also relatively simple, which leads to its low prices as well. Compared with FBT splitters, the technology of PLC splitter is more complicated and expensive. It uses semiconductor technology production. Hence it is more difficult to manufacture PLC splitters. And the price of the device is higher.

Operating Wavelength

FBT splitters only supports three wavelengths: 850 nm, 1310 nm and 1550 nm, which makes its inability to works on other wavelengths. While PLC splitter can support wavelength from 1260 to 1650 nm. The adjustable rang of wavelength allows PLC splitter more wide applications.

Split Ratio

The split ratio of FBT splitter is up to 1:32, while the ratio PLC splitter goes up to 64, providing a high reliability. Furthermore, the signal in PlC splitter can be split equally due to technology implemented.

Temperature

In certain areas, temperature can be a crucial factor that affects the performance of optical components. Therefore, sometimes devices with good cold resistance is also vital. FBT splitter can work stable under the temperature of -5 to 75℃. PLC splitter can work at a wider temperature range of -40 to 85 ℃, providing relatively good performance in the areas of extreme climate.

Apart from the differences mentioned above, there are still other differences between FBT splitter and PLC splitter. For example, compared with FBT splitter, the size of PLC splitter is more compact. Hence, PLC spitter is more suitable for density applications.

Conclusion

In conclusion, this article introduce the fiber optical splitters and the differences between FBT splitter and PLC splitter. It’s significant to choose the most suitable splitters for your networks. There are a variety of splitters avaible in Fiberstore. If you want to know detailed information, please visit FS.COM.

How to Ensure a High Quality PLC Splitter?

PLC (Planar Lightwave Circuit) splitter is an important component in PON (passive optical network) where a single optical input is split into multiple outputs. This makes it possible to deploy a Point to Multi Point physical fiber network with a single OLT (optical line terminal) port serving multiple ONTs (optical network terminal). The most common split ratios are 1:N or 2:N. N represents the output ports, usually as 2, 4, 8, 16, etc. The optical input power is distributed uniformly across all output ports. The PLC splitter shares the cost and bandwidth of the OLT and reduces fiber lines. This article will tell about how to keep a high quality PLC splitter from manufacturing to testing sides.

plc-assured-program

Key Manufacturing Steps of PLC Splitter

PLC splitter is composed by many miniature parts. Among them, there are three main components: fiber array for the input and output, and the chip. These three main components decide whether the PLC splitter is of good quality or not. Let’s see the key manufacturing steps of a PLC splitter.

Step1. Components Preparation

The PLC circuit chip is designed and embedded on a piece of glass wafer. Each end of the glass wafer is polished to ensure high precision flat surface and high purity. The V-grooves are grinded into a glass substrate. A single fiber or multiple ribbon fiber is assembled onto the glass substrate. This assembly is polished.

Step2. Alignment

After preparing the three components, it’s time for alignment. The input and output fiber array is set on a goniometer stage to align with the chip. Physical alignment between the fiber arrays and the chip is monitored through the power level output from the fiber array. Epoxy is then applied to the fiber array and the chip to affix their positions.

Step3. Cure

The assembly will be placed in a UV chamber to be fully cured at a controlled temperature.

Step4. Packaging

The bare aligned splitter is assembled into a metal housing where fiber boots are set on both ends of the assembly. A temperature cycling test will be done for a final screening to ensure the final product condition.

Step5. Testing

Optical testing items include insertion loss, uniformity and polarization dependent loss. This testing is to ensure the splitter compliant to the optical parameters in GR-1209 CORE specification.

Testing Standards of PLC Splitter

Then how to determine the quality of a PLC splitter? The GR-1209 standards provides comprehensive optical performance criteria. The following will introduce these specifications such as optical bandpass, insertion loss, return loss, uniformity and directivity.

Optical Bandpass

In a PON system, the downstream transmission uses 1490nm wavelength and 1310nm wavelength for the upstream transmission. Besides, the requirement for RF video overlay and network testing/maintenance should also be considered. The transmission wavelength for RF video is 1550 nm. And the wavelengths for networking testing and maintenance are 1550 nm and 1625 nm. So the standard opterating wavelength for a PON splitter is determined as 1260~1650 nm which covers most of the optical bands.

Insertion Loss

The optical splitter has the largest attenuation in a PON system. The insertion loss transfers from the input port to the output port. In order to conserve the power of a PON system, the insertion loss should be reduced to the least. There are formulas to calculate the maximum insertion loss of an optical splitter in a PON system according to the GR-1209 standard: 0.8 + 3.4 log2N (for 1xN optical splitter) and 1.0 + 3.4 log2N. To decide if the insertion loss is in the qualified range, you need to choose one formula to calculate.

Return Loss

Optical return loss is part of the power transferred from one input port back to the same input port or from an output port back to the same output port. A high return loss will influence the data transmission quality. So it’s important to minimize the noise to keep the PON system power for a better transmission.

Uniformity

Uniformity means the maximum insertion loss value between one input port and any two output ports or between two input ports and one output port. This can ensure that the transmission power at each splitter output port is the same in a PON system to simplify the network design.

Directivity

Directivity is the part of power transferred from one input port to another input port or from an output port to another output port. For a 2xN optical splitter, when light injects into one of the input ports, light doesn’t only propagate out of the output ports. Some of the light propagates back through the second input port. And when the light injects into one of the output ports, light propagates back through the other output ports. In a bidirectional transmission system such as a PON, directivity is useful to reduce signal crosstalk. A high directivity value will increase the insertion loss due to the optical power loss.

Conclusion

FS.COM provides a variety of PLC splitters including 1×2, 1×4, 1×8, 1×16, 1×32, 1×64; 2×2, 2×4, 2×8, 2×16, 2×32, 2×64 in various package options, which offer cost-effective solutions for your applications. To ensure high performance, we have set a quality assurance program for PLC splitter. We always care every detail both in manufacture and testing. For detailed information, please contact us via sales@fs.com.

Brief Introduction of Fiber Optic Splitter

Fiber optic splitters are quite important in today’s optical network. Splitters can help users maximize the functionality of optical network circuits. A fiber optical splitter is a passive optical device that can split, or separate, an incident light beam into two or more light beams. These beams may or may not have the same optical power as the original beam. The outputs of a splitter can have various degrees of throughput. And that is very useful to decide whether the splitter is used for network monitoring or for a loss budget in a passive optical network (PON) architecture when designing optical networks. This article will give brief introduction of fiber optical splitter.

There are two kinds of the most commonly used fiber optical splitters. And they are planar lightwave circuit (PLC) and fused biconical taper (FBT). PLC splitters (as shown in the following picture), from the name, it’s easy to find out that PLC splitter is based on planar lightwave circuit technology. It uses an optical splitter chip to divide the incoming signal into multiple outputs. It consists of three layers including a substrate, the waveguide, and the lid. The waveguide layer accepts the incoming optical signal and passes it to the outputs. FBT splitter is fused with a heat source similar to a fusion splice. Fibers are aligned in a group to create a specific location and length and will be fused with heat to meet the desired parameters such as insertion loss. Fused fibers are put in a V-shaped groove and fixed in a silica tube with a mix of epoxy and silica powder to get the proper heat.

1x16-Fiber-PLC-Splitter

Fiber Optical Split Ratios

Fiber optical splitters vary in numbers of inputs and outputs. The split ratios are based on the network use of fiber optical splitters. In a PON architecture, it uses splitters to split a single fiber into multiple fibers to feed as many as 64 end users. A typical split ratio in PON application is 1:32, or one in coming fiber split into 32 outputs.

Large split ratios like 1:32 or 1:64 are often found in some kind of housing. That’s because with so many fibers related to these splitters, a platform should be used to manage the splitter modules, patch modules, patch cables, etc. Most often a high-density fiber bay is required so that the splitters can be all placed in a distribution site or a PON enclosure. The PON cabinet plays a significant role in today’s applications since the space is so limited. When it comes to a high-density frame with varying split ratios and large number of patch cords, the distribution frame is critical for a good cable management.

Cost Saving in FTTx/PON Applications

As the city grows and subscribers increase, the network architect must deal with multiple distribution points and backhaul. To meet so many subscribers’ requirements, the flexibility in head-end locations, distribution points and split ratios becomes more significant. To network service provider, saving capital and operational costs is important.

On one side, fiber optical splitters can save fiber cost by reducing the fiber usage and that’s why they are so important in FTTx/PON networks. Using a single fiber to feed as many as 64 end users significantly reduces the fiber quantity. On the other side, the long-term operation costs can’t be ignored either in optical network splitter applications. That’s one of PON’s advantages. For example, it can decrease the power consumption.

Another way to save cost is to ease maintenance and increase the flexibility for smaller split ratios, which lead to more bandwidth per subscriber. For example, a service provider would likely need to split the optical terminal line (OLT) with a 1:2 splitter, and adjust the split ratios from there based on delivery to residential (1:32). These multiple split ratios can create flexibility in the network as long as the utilization of transport electronics such as OLT is concerned. Loss budget can be greatly influenced by the use of multiple splitters.

Conclusion

From the above content, to run a network architecture, the network success and cost should be paid attention. And fiber optical splitter is such a good device to increase the efficiency of optical infrastructure and save the capital and future operational cost.

The Latest Generation of PON – NG-PON2

To meet the large demand for high capacity transmission in optical access systems, 10G-PON (10G Passive Optical Network) has already been standardized by IEEE (Institute of Electrical and Electronics Engineers) and ITU (International Telecommunication Union). To enable the development of future optical access systems, the most recent version of PON known as NG-PON2 (Next-Generation Passive Optical Network 2) was approved recently, which provides a total throughput of 40 Gbps downstream and 10 Gbps upstream over a single fiber distributed to connected premises. The migration from GPON to 10G-PON and NG-PON2 is the maturity of technology and the need for higher bandwidth. This article will introduce the NG-PON2 technology to you.

GPON 10G-PON NG-PON2

What Is NG-PON2?
NG-PON2 is a 2015 telecommunications network standard for PON which was developed by ITU. NG-PON2 offers a fiber capacity of 40 Gbps by exploiting multiple wavelengths at dense wavelength division multiplexing (DWDM) channel spacing and tunable transceiver technology in the subscriber terminals (ONUs). Wavelength allocations include 1524 nm to 1544 nm in the upstream direction and 1596 nm to 1602 nm in the downstream direction. NG-PON2 was designed to coexist with previous architectures to ease deployment into existing optical distribution networks. Wavelengths were specifically chosen to avoid interference with GPON, 10G-PON, RF Video, and OTDR measurements, and thus NG-PON2 provides spectral flexibility to occupy reserved wavelengths in deployments devoid of legacy architectures.

How Does NG-PON2 Work?
If 24 premises are connected to a PON and the available throughput is equally shared then for GPON each connection receives 100 Mbps downstream and 40 Mbps upstream over a maximum of 20 km of fiber. For 10G-PON, which was the second PON revision, each of the 24 connections would receive about 400 Mbps downstream and 100 Mbps upstream. The recently approved NG-PON2 will provide a total throughput of 40 Gbps downstream and 10 Gbps upstream over a maximum of 40 km of fiber so each of the 24 connections would receive about 1.6 Gbps downstream and 410 Mbps upstream. NG-PON2 provides a greater range of connection speed options including 10/2.5 Gbps, 10/10 Gbps and 2.5/2.5 Gbps. NG-PON2 also includes backwards compatibility with GPON and 10G-PON to ensure that customers can upgrade when they’re ready.

NG-PON2 Work Principle

NG-PON2 Advantages
The NG-PON2 technology is expected to be about 60 to 80 percent cheaper to operate than a copper based access network and provides a clear undeniable performance, capacity and price advantage over any of the copper based access networks such as Fiber to the Node (FTTN) or Hybrid Fiber Coax (HFC). At present, three clear benefits of NG-PON2 have been proved. They are a 30 to 40 percent reduction in equipment and operating costs, improved connection speeds and symmetrical upstream and downstream capacity.

Reduced Costs
NG-PON2 can coexist with existing GPON and 10G-PON systems and is able to use existing PON-capable outside plant. Since the cost of PON FTTH (Fiber to the Home) roll out is 70 percent accounted for by the optical distribution network (ODN), this is significant. Operators have a clear upgrade path from where they are now, until well into the future.

Improved Connection Speeds
Initially NG-PON2 will provide a minimum of 40 Gbps downstream capacity, produced by four 10 Gbps signals on different wavelengths in the O-band multiplexed together in the central office with a 10 Gbps total upstream capacity. This capability can be doubled to provide 80 Gbps downstream and 20 Gbps upstream in the “extended” NG-PON2.

Symmetrical Upstream and Downstream Capacity
Both the basic and extended implementations are designed to appeal to domestic consumers where gigabit downstream speeds may be needed but more modest upstream needs prevail. For business users with data mirroring and similar requirements, a symmetric implementation will be provided giving 40/40 and 80/80 Gbps capacity respectively.

With the introduction of NG-PON2, there is now an obvious difference between optical access network and copper access network capabilities. Investment in NG-PON2 provides a far cheaper network to operate, significantly faster downstream and upstream speeds and a future-proof upgrade path all of which copper access networks do not provide, thus making them obsolete technologies. Telephone companies around the world have been carrying out trials of NG-PON2 and key telecommunication vendors have rushed NG-PON2 products to market.

Original article source: 
http://www.cables-solutions.com/the-latest-generation-of-pon-ng-pon2.html

 

A Guide for PON

Nowadays, there is a growing popularity of Video-on-Demand (VoD), VoIP and increased IPTV deployment. Providers aim to offering fiber-to-the-home (FTTH), (fiber-to-the-building) FTTB and fiber-to-the-curb (FTTC) solutions through advancing passive optical network (PON) technology. The term “PON” may confuse you for its complexity and extensiveness. Details are as followed.

PON is a single, shared optical fiber that uses inexpensive optical splitters to divide the single fiber into separate strands. It can build up a point-to-point topology supporting 1Gbps transmission to home and business typically within 20km. PON system is called “passive” because that there are no active electronics within the access network. It uses optical splitters to separate and collect signals rather than electrically powered switching equipment.

PON consists of an Optical Line Terminal (OLT) connected to multiple Optical Network Units (ONUs) via an Optical Distribution Network (ODN).

OLT: it is a device at the service provider’s central office, performing conversion between the electrical signals used by the service provider’s equipment and the fiber optic signals used by the passive optical network and coordinating the multiplexing between the conversion devices on the other end of that network.

ODN: it is used for distributing signals to users in a telecommunications network by optical fiber. ODN has been made up entirely of passive optical components particularly singlemode optical fibers and optical splitters.

ONUs: they are devices near end users, delivering traffic-load information provided by OLTs to each end user.PON System

PON system has achieved significant deployment in today’s FTTx networks especially in FTTH networks as the development of Gigabit passive optical network (GPON) and Ethernet passive optical network (EPON). Nowadays, GPON and EPON are the mostly widely used types of PON for their low cost, high bandwidth, great flexibility and easy management, etc.

GPON: it is defined by ITU-T recommendation series G.984.1 through G.984.6. It can transport not only Ethernet, but also ATM and TDM (PSTN, ISDN, E1 and E3) traffic. It supports services like carrying video and delivering video on single fiber distribution, allowing low-consuming transmission, more efficient maintenance, cabling and overall performance.

EPON: it is defined by the Ethernet standard rather than by the ATM standard, making you utilize the economies-of-scale of Ethernet. It can provide simple and easy-to-manage connectivity to Ethernet-based, IP equipment both at the customer premises and at the central office. It is perfect for voice and video traffic solution as with other Gigabit Ethernet media.GPON and EPON

 For more information about OLTs, Optical Splitters and ONUs, please visit Fiberstore.