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Functions of ONT and OLT in GPON Network

Gigabit passive optical network (GPON) is a point-to-multipoint access mechanism providing end users with the ability to consolidate multiple services onto a single fiber transport network. To realize this technology, many devices are used to support the network, such as optical splitter, ONT, OLT, etc. In this article, we will mainly discuss the functions of ONT and OLT in GPON network.
Functions of ONT and OLT
Optical network terminal (ONT) is an optical modem that connects to the termination point with an optical cable. It is used at end user’s premise to connect to the PON network on one side and interface with the user on the other side. Data received from the customer end is sent, aggregated and optimized by the ONT to the upstream OLT. ONT is also known as optical network unit (ONU). ONT is an ITU-T term, while ONU is an IEEE term. They both refer to the user side equipment in GPON network. A small difference between them might be the application locations. ONU can work in different temperature and weather conditions.
Optical line terminal (OLT) is the endpoint hardware equipment located in a central office of the PON network. Its basic function is to control the float information in optical distribution network (ODN) to go in both directions. OLT converts the standard signals used by fiber optic service (FiOS) to the frequency and framing used by PON system. In addition, it coordinates the multiplexing between the ONT conversion devices. There are two float directions for OLT system. One is the upstream direction to distribute different types of data and voice traffic from users. The other is the downstream direction which gets data, voice and video traffic from metro network or from a long-haul network and sends it to all ONT modules on the ODN.
How to Add or Delete ONT on OLT?
Way to Add ONT on OLT
If the password of an ONT is obtained, you can run the ONT add command to add the ONT offline. However, if the password is unknown, you can run the port portid ont-auto-find command in the GPON mode to enable the ONT auto-find function of the GPON port, and then run the ONT confirm command to confirm the ONT. When the ONT is added, you need to run the display ONT info command to see the current status of ONT. If the control flag is active,
Way to Delete ONT on OLT
When you need to delete the ONT on OLT, please use the delete command. Then ONT configuration data is deleted with the deletion of the ONT and the online ONT is forced offline. ONT can’t be deleted when it has been configured with other services. You need to unbind the service first before delete the ONT.
How to Troubleshoot ONT?
To troubleshoot the ONT, you should remember that the most important step is to connect your computer directly to the ONT to see if the problem goes away. You can use the Ethernet cable for connection. If the problem still exists, you can reconnect the ONT power supply to clear its internal cache. If the network can not be restored after the above methods, maybe you need to consult professionals for help.

Media Converters Provide Cost-effective Soluton

Network complexity, demanding applications, and also the growing number of devices around the network are driving network speeds and bandwidth requirements higher and forcing longer distance requirements within the LANs. However, Media Converters provide solutions to these complaints, utilizing the optical fiber if it is needed, and integrating new equipment into existing cabling infrastructure.
What is the Media Converter? Media converter can be a device that functions like a transceiver, converting the electrical signal found in copper UTP network cabling into light waves used in fiber optic cabling. It gives you seamless integration of copper and fiber, and other fiber types in Enterprise LAN networks. Media converter supports numerous protocols, data rates and media types.
Fiber optic connectivity is important when the distance between two network devices exceeds the transmission distance of copper cabling. Copper-to-fiber conversion using media converters enables two network devices with copper ports to become connected over extended distances via fiber optic cabling. Media converters provide fiber-to-fiber conversion from multimode fiber to single-mode fiber or single-mode fiber to multimode fiber, and convert a dual fiber link to single fiber using Bi-directional (BIDI) data flow. They can also convert between wavelengths for WDM applications with devices such as WDM multiplexer. Media converters are typically protocol specific and are available to guide a wide variety of network types information rates.
For example, the Fiber-To-Fiber Media Converter can offer connectivity between multimode and single-mode fiber, between different power fiber sources and between dual fiber and single-fiber. It extends a multimode network across single-mode fiber with distances as much as 140km. Within this application, two Gigabit Ethernet switches equipped with multimode fiber ports are connected by using a couple of Gigabit Fiber-To-Fiber Media Converters, which convert the multimode fiber to single-mode and let the cross country connection between the switches. Furthermore, they support conversion from one wavelength to a new with all the single mode to multimode converter or multimode to singlemode media converter. These media converters are usually protocol independent and designed for Ethernet,and TDM applications.
Media converters do a lot more than convert copper-to-fiber and convert between different fiber types. Media converters for Ethernet networks can support integrated switch technology, and offer the opportunity to perform 10/100M and 10/100/1000M rate switching. Additionally, media converters can support advanced bridge features, including VLAN, QoS prioritization, Port Access Control and Bandwidth Control – that facilitate the deployment of recent data, voice and video to get rid of users. Media converters can offer all these sophisticated switch capabilities in a, cost-effective device.
Media converters save CAPEX by enabling interconnection between existing switches, servers, routers and hubs; preserving the investment in legacy equipment. They reduce CAPEX by avoiding the necessity to install new fiber links by enabling WDM technology through wavelength conversion. Media converters also reduce network OPEX by helping troubleshoot and remotely configure network equipment that is at distant locations, not waste time and funds when there is not just a network administrator on the distant location.
Media converters are necessary to produce a more reliable and cost-effective network nowadays. So, where are we able to get high quality Media Converters with reasonable price? Visit Fiber Media Converter Solution in fiber-mart.com now.

CWDM System Testing Process

With the explosion of CWDM, it is very necessary to formulate a basic testing procedure to certifying and troubleshooting CWDM networks during installation and maintenance. Today, one of the most commonly available test methods is the use of an OTDR or power source and meter, which is capable of testing the most commonly wavelengths, 1310, 1490, 1550 and 1625nm.
This article here is based on the pre-connectorized plug and play CWDM systems that allow for connecting to test equipment in the field:
In the multiplexing module of a pre-connectorized CWDM system, wavelengths are added to the network through the filters and transmitted through the common port. The transmitted wavelengths enter the COM port in the de-multiplexing module and are dropped. All other wavelengths present at the MUX/DeMux module are went through the express port.
Most of today’s OTDRs have expanded capability for testing wavelengths in addition to 1310 and 1550 nm. The OTDR allows partial testing of such system offered in test equipment source. The OTDR allows partial testing of these systems by using the flexibility of pre-connectorized solutions. This is done by switching connections within the CWDM field terminal to allow for testing portions of the non-1310/1550 nm optical paths.
To test the 1310nm, the first step is to test the downstream portion of a system at 1310 nm by connecting the OTDR to the 1310 nm input on the CWDM MUX located at the headend. Then switch the test leads over the the upstream side and repeat. Test method is the same for both the downstream and upstream paths.
1550 nm testing is performed similarly by switching the test leads to the 1550nm ports. If additional wavelengths are present, you need to follow the procedures below:
Using the 1550 nm test wavelength, switch the OTDR connection to the 1550 nm input port on the headend MUX. Have a technician stationed at the field terminal connect the drop cable leg connectors for the 1570 nm customer to the 1550 nm port on the Mux/demux device. What should be noted is that in a play and plug solution this should not require repositioning where the drop cable passes through the OSP terminal. Test the downstream 1570 nm passive link at 1550 nm, and then repeat for the 1570 nm upstream side. When testing is complete, have the technician switch the connections for the 1570 nm drop back to the 1570 nm ports on the field MUX/DeMUX device as shown in Figure 6. Repeat this process for the 1590 nm, 1610 nm drop cables and other wavelengths present. Finally, test the 1550 nm path normally with the 1550 nm drop cable connected to the 1550nm MUX/DeMUX ports.
Since the OTDRs is able to test at 1490 or 1625 nm, the drop cables under test could be connected to the EXP port of the module and tested at 1490 or 1625 nm respective wavelength, without having to connect each to the 1550 nm port. Otherwise the procedure is the same.
As CWDM network become more and more common the data they carrying has also become critical. The procedure introduced here allows for testing modular pre-connectorized CWDM systems with standard optical test equipments. Relative channel power can be measured with a wide-band fiber optic power meter at the filter outputs or at other points in the network with the aid of a wavelength selective test device or with an optical spectrum analyzer.

Fiber Optic Visual Light Testers

Visual fault locators can be part of OTDR, which is able to locate the breakpoint, bending or cracking of the fiber glass. It can also locate the fault of OTDR dead zone and make fiber identification from one end to the other end. Fiber optic visual fault locators include the pen type, the handheld type and portable visual fault locator. fiber-mart.com also supply a new kind of fiber optic laser tester that can locates fault up to 30km in fiber optic cable.
The new visual fault locator fiber optic laser tester 30km is especially designed for field personnel who need an efficient and economical tool for fiber tracking, fiber routing and continuity checking in an optical network during and after installation. It can send fiber testing red light through fiber optic cables, then the breaks or faults in the fiber will refract the light, creating a bright glow around the faulty area. Its pen shape made it very easy to carry, and its Cu-alloy material shell made it sturdy and durable, 2.5nm universal interface make it more attractive. The inspection distance various according to different mode.
Features
Easy to check fiber faults with visual red laser light
FC, SC, ST General interface
Sturdy and durable shell
Constant output power
Long inspection distance
Operates in either CW (Continuous wave) or pulse (Both modes are available)
Pen pattern design, convenient for use and carry
Dust-proof design keeps fiber connectors clean
Compact in size, light in weight, red laser output, both SM and MM available
fiber-mart.com provides enough stock of fiber optic visual light testers which usually be shipped out in a short time, and can be shipped out in 2-4 business days. We offer 1 years warranty for the quality of these products, so customers can place the order with 100% confidence!

How to Terminate Fiber Optic Cables?

Since the late 1970s, various connectors and termination methods have been brought to market. Now in the common case, cables are terminated in two ways: use connectors to make two fibers jointed or to connect the fiber to other network gears; use splices to make a permanent joint between two fibers. And for the former method, you may have little confusions to deal with it. So today this paper will teach you how to terminate by taking an example of fiber optic cable using epoxy.
First and foremost, use a proper fiber stripper to carefully slide the jacket off of the fiber to a bare fiber. When you are doing this, be careful that try to avoid breaking the fragile glass fiber. After that, mix the epoxy resin and hardener together and load it into a syringe (If you use the pre-loaded epoxy syringes that are premixed and kept frozen until use, then you don’t do that). And next you must inject the epoxy from the syringe directly into the connector ferrule.
Once you have well prepared the epoxy for your connector, you can insert the fiber cable gently into the terminus inside the connector wall and make the bare fiber core stick out about a half an inch from the front of the ferrule. In the case that your cable is jacketed, you may need a crimping tool, such as Sunkit Modular Crimping Tool, to secure the connector to the jacket and strength the cables. Usually two crimp tools would be perfect to this operation.
Next, you can just wait the epoxy to cure. During this process, in order to make sure the end of the fiber is not damaged while curing, you should place the connected end in a curing holder. And when this is done, just place the cable and curing holder into a curing oven. But you may worry about “wicking” while curing with a conventional oven. All you have to do to avoid that is to make the end face down, which can ensure the epoxy does not come out of the back side of the connector and compromise the strength member of the cable. Remember: your epoxy curing must in accurate times and temperatures.
After the epoxy cured sufficiently, fiber cleaver tools will be in use to cleave the excess protruding fiber core so that it could make the fiber close as much as possible to the ferrule tip in case of fiber twisting. Once cleaved, you have to dispose of the fiber clipping. There is a point you should think highly of that you must use a regular piece of tape to retain your fiber debris, or they will easily end up in your skin or even in your eyes or respiratory system.
When you finished the fiber cleaved work, you could need fiber polishing tool to remove the excess epoxy from the ferrule tip and buff out any imperfections on the surface of the fiber. A smooth fiber surface can help to reduce the loss of the light. Last, if you have done all the above work, you may move on to the cleaning of the ferrule and fiber tip. After that, the whole termination procedure is done.

Photonic Integrated And High-speed Optical Interconnection Technology

Currently, in the field of active optical devices, high-speed optical communication (40G/100G), broadband access FTTH, 3G and LTE wireless communication, high-speed optical interconnection, chips applied in intelligent Fiber Optic Network, device and module technologies are competing to become the hot spots of development. And the photonic integrated, high-speed optical signal modulation technique, high-speed optical device packaging technology, as the representative of the optical device platform technology are also increasingly being valued by the majority of OC manufacturers.
The Technology Development And Breakthrough Of Active Optical Devices
To meet the growing demand for bandwidth, while continuing to reduce the capital, operation and maintenance expenses, will continue to be the two main driving force to promote the development of optical communication technology. In order to meet the evolving needs of the system, the development of active optical communication device involves many technologies, however, in recent years there are several technologies deserve special attention, including 40G/100G high speed transmission device and module technology, the next generation fiber access technology, ROF (Radio Over Fiber) components and module technology, optical integration technology, high-speed interconnect optoelectronic components and modules, etc.
Optical Integration Technology Is Worth Looking Forward
Optical integrated devices due to its low cost, small, easy to large-scale assembly, high work rate, stable performance and other advantages, as early as the 1970s, it caused the world’s attention and research. In the ensuing three decades, with the rapid development of optical waveguide production technology and a variety of fine processing technology, optical integrated devices are heavily into the business, particularly some optical passive components based on Planar Lightwave Circuit (PLC), such as Planar Lightwave Circuit Splitter, arrayed waveguide grating (AWG) and so on, have become hot products in optical communication on the market. In the field of optical active devices, the active integration products are still far from large-scale commercial, but with the successful development of some advanced technologies such as Dispersion Bridge Grating, active devices based on PLC recently made great progress.
The develop direction of optical integration technology can be divided into two categories: monolithic and hybrid integration. Monolithic integration refers to the semiconductor or optical crystal substrate, over the same production process, integrating all the components together, such as: PIC and OEIC technology; the hybrid integration refers to through different production processes, making part of the components, then assembled in the semiconductor or optical crystal substrate.
Previously, the actual production process of Si-based hybrid integration has been quite complex, but recently, a number of research institutions had improved the traditional hybrid integration technology based on flip, and made great progress. Among them, the most remarkable achievements include two items: The first is the University of California at Santa Barbara, in cooperation with Intel company researched hybrid integrated device based on Wafer level; second is the Ghent University based chip and the wafer hybrid integrated devices.
In recent years, the development of optical integration technology, making it quickly became a very worth looking forward platform technology in optic communication, is expected to be widely applied.
High-speed Optical Interconnection Technology Beyond Imagination
High speed optical interconnection technology is realized by parallel Fiber Transceiver and Ribbon Cable or fiber optic cable. Parallel optical module is based on VCSEL array and PIN array,wavelength of 850nm, suitable for 50/125 μm and 62.5/125 μm multimode fiber. Its electrical interface uses standard MegArray connectors in package, optical interface uses standard MTP/MPO ribbon cable. At present more common parallel optical transceiver module has 4 channels and 12 channels. In the current market, the more common high-speed parallel optical modules include: 4 × 3.125Gb/s (12.5Gb/s) parallel optical module, applications such as high-end computer systems, blade servers short distance interconnection; 12 × 2.725Gb/s (32.7Gb/s) parallel optical module, used in high-end switching equipment as well as backplane connection. Parallel optical module applications are gradually becoming more mature.
At present, the rise of applications such as super computer, cloud computing, short-distance high-speed data communication, directly promoting the rapid development of high-pspeed optical interconnection technology, its size of the market and technology development will beyond people’s imagination.