8000 meters deep submarine actually there are optical cables? Is the person who spreads the cable is Iron Man?

If you compare the earth to a computer motherboard. From the phone poles with cables to the warning signs that lay the optical fibers, the world we live in is surrounded by countless lines. In fact, the Internet infrastructure that we can see with our naked eyes is only the tip of the iceberg, and there are countless cables laid in the depths of the dark ocean.You must be more interested in what you would like to eat than you would like to eat at dinner.

1.On the surface of the sea, the ship releases the cable.

图片12.Under the sea, cable ploughs fix the cable to the bottom of the sea. There is also a repeater every 40km to 60km.

图片23.Guaranteed signal.How many optical cables do you need to bring?

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Did you see the turntable on the boat?  It can be said to be super long

图片4The process looks simple, Someone has to ask, is the pressure on the bottom of a few kilometers so large that the fiber is not easily damaged?

Responsibly tell you that submarine cables are more fragile than underground cables, and that different depths of maintenance are different:

1.The general cable fault location receives and sends a complete set of signals first, because the damage of the optical cable is usually the internal fiber breakage, the breakage location will reflect the signal, and the recovered reflection signal is compared with the shape and time of the signal calculated by the mathematical algorithm. Locate the specific location of the fiber breakage.

2.The cable repair ship went to the accident site to repair it. If the water depth is within two kilometers, an underwater robot is generally used to guide to the fault location through an artificial signal, and the damaged optical cable is cut off, and the remaining two ends are pulled back to the repair ship for repair.

3.If the water depth exceeds 2,000 meters, due to pressure problems, deep water grabs will be used, and the image is a hook. If it is a sandy seabed, the optical cable will be directly returned to the sea surface. If it is a rocky seabed, the grab must be along a certain length of the optical cable, so that the position of the optical cable can be adjusted more easily to prevent it from being pinched by rocks.图片5

4.If the water depth is too deep, a single grab cannot pull the entire cable directly back to the surface. At this point, the fiber optic cable needs to be cut off, and now a head A1 is brought back to be fixed with a buoy, and then the other head A2 is pulled with another grab.

5.Fiber optic cable repair is mainly the work of fiber-optic welding. A2 is welded to the newly added spare cable B. Then the repair boat is close to the buoy, and the A1 is rejoined to the remaining part of B. The repaired cable is longer than the original one. The new cable is U-shaped on the sea floor. After the welding is completed, wait until the communication test is successful before returning the cable.

Therefore, the cost of submarine cable is quite high. The cost of a transoceanic fiber cable is several hundred million US dollars. Coupled with the monopoly of real estate giants, the monopoly access prices of domestic operators, the terrible reasons for the high cost of broadband in Hong Kong have also been explained.

Understanding CWDM DWDM MUX/DEMUX

In the communications market,  Wavelength Division Multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light.

In the communications market,  Wavelength Division Multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This technique enables bidirectional communications over one strand of fiber, as well as multiplication of capacity.

The WDM is divided into three types (WDM, CWDM and DWDM) on the basis of wavelength difference among the three.

CWDM Mux/Demux

Dense Wavelength Division Multiplexing (CWDM) networks need multiplexer/demultiplexer (MUX/DEMUX) modules to combine and split wavelength channels at standard ITU grid. These modules are generally called CWDM MUX/DEMUX.

The CWDM Mux/Demux is a universal device capable of combining nine optical signals into a fiber pair. It is designed to support a broad range of architectures, ranging from scalable point-to-point links to two fiber-protected rings. The market-standard LGX™ packaging of the CWDM Mux/Demux enables easy deployment in existing LGX-compatible frames or WaveReady 3500F shelves.

The CWDM Mux/Demux is designed to interoperate with both the WaveReady line of transponder and optical regenerator solutions as well as CWDM transponders and small form-factor pluggables (SFPs) used in widely available transmission equipment. With billions of field operating hours, the industry leading Lumentum optical multiplexing technology offers unparalleled reliability and leading-edge performance.

CWDM Mux/Demux is a flexible network solution for WDM optical networks. At most 18 full-duplex wavelengths can be added over a single fiber trunk which greatly alleviates fiber exhaustion. With low insertion loss and high stability, CWDM Mux/Demux is applied to many operations, such as CATV links, WDM systems, test and measurement, metro and access networks, FTTH networks, etc. The deployment of CWDM Mux/Demux is transparent and clear. Its compact form factor enables a much easier manipulation. Only coarse wavelengths can be transmitted over the fiber which reduces the WDM system cost.

Three kinds of CWDM Mux/Demux are widely used in the application. They are 1RU 19″ rack chassis CWDM Mux/Demux, half 19″/1RU CWDM Mux/Demux and splice/pigtailed CWDM Mux/Demux. CWDM Mux/Demux in 19 inch rack mount package is often used for CWDM, EPON and CATV network. Half 19″/1RU CWDM Mux/Demux is packed in LGX box using thing film coating and non-flux metal bonding micro optics packaging. Splice/pigtailed CWDM Mux/Demux is packed in the ABS box package based on standard thin film filter (TFF) technology.

DWDM Mux/Demux

Dense Wavelength Division Multiplexing (DWDM) networks need multiplexer/demultiplexer (MUX/DEMUX) modules to combine and split wavelength channels at standard ITU grid. These modules are generally called DWDM MUX/DEMUX.

DWDM Mux/Demux conveys optical signals in a more dense wavelength. It is especially used for long distance transmission where wavelengths are highly-packed together. The maximum delivered wavelengths can reach up to 48 channels in 100GHz grid (0.8nm) and 96 channels in 50GHz grid (0.4nm). DWDM Mux/Demux uses a reliable passive WDM technology that achieves low insertion loss. And it provides a solution for adding WDM technology to any existing network device. Applications like point-to-point DWDM fiber optimization, linear add/drop DWDM fiber optimization, external optical monitoring are typically using DWDM Mux/Demux module.

The functionality of DWDM (Dense Wavelength Division Multiplexing) resembles to the one of CWDM. The DWDM channel spacing is 0.8/0.4 nm (100 GHz/50 GHz grid). This small channel spacing allows to transmit simultaneously more information. Currently a restriction on wavelengths between 1530 nm and 1625 nm exists which corresponds to the C and L band. DWDM wavelengths are more expensive compared to CWDM caused by the need of more sophisticated transceivers.

Likewise, 1RU 19″ rack chassis DWDM Mux/Demux, Half 19″/1RU DWDM Mux/Demux and splice/pigtailed DWDM Mux/Demux are three divisions of DWDM Mux/Demux modules. The first type is in 19 inch rack mount package used for long-haul transmission over C-band range of wavelengths. The second one is in LGX package used for PDH, SDH/SONET, Ethernet services transmission. The last one is in ABS box package and its pigtails are labeled with wavelengths.

Comparison Between CWDM and DWDM System

The difference between CWDM and DWDM lies in the channel spacing between neighbored wavelengths, for CWDM 20 nm and for DWDM 0.8/0.4 nm (using 100 GHz/50 GHz grid). this advantage for an efficient CWDM/DWDMintegration. Thereby up to sixteen DWDM channels are transmitted simultaneously in only one CWDM channel (1530 nm and 1550 nm). Thus an easy-to-realize channel extension can be achieved under continued use of existing CWDM components.

Price differenceCWDM system carries less data, but the cabling used to run is less expensive and less complex. A DWDM system has much denser cabling and can carry a significantly larger amount of data, but it can be cost prohibitive, especially where there is a need for a large amount of cabling in an application.

Transmission distanceDWDM system is designed for longer distance transmission as stated above. They can transmit more data over a significantly larger run of cable with less interference than a comparable CWDM system. If there is a need for transmitting the data over a long range, DWDM system will likely be the best in terms of functionality of the data transmittal and the lessened interference over the longer distances that the wavelengths must travel.

CWDM system cannot transmit over long distances because the wavelengths are not amplified, and therefore CWDM is limited in its functionality over longer distances. Typically, CWDM can travel anywhere up to about 100 miles (160 km), while an amplified DWDM system can go much further as the signal strength is boosted periodically throughout the run. As a result of the additional cost required to provide signal amplification, the CWDM solution is best for short runs that do not have mission critical data.

To sum up, before buying We should first understand the differences between them,Fiber-Mart provides a series of CWDM DWDM MUX/DEMUX modules with as more as 18 channels (20nm spaced) in simplex or duplex configurations. All the CWDM  DWDM modules are available with three types of packaging: ABS Pigtailed Box, Rack Chassis and LGX Cassette. For more details, please visit www.fiber-mart.com. Please not hesitate to contact us for any question. E-mail: service@fiber-mart.com

Introduction of SM to MM Media Converters

What is SM to MM Media Converter?

Enterprise networks often require conversion from MM to SM fiber, which supports longer distances than MM fiber. Mode conversion is typically required when lower cost legacy equipment uses MM ports but connectivity is required to SM equipment, a building has MM equipment, while the connection to the service provider is SM, and MM equipment is in a campus building but SM fiber is used between buildings.

SM to MM Media Converters are Fiber-to-Fiber Media Converters used to conduct the transparent conversion between singlemode and multimode fiber for applications where media conversion required between multimode segments separated by long distances. Fiber-Mart provides various type of singlemode to multimode media converters, which fulfill the conversion at 850/1310nm or 850/1310/1550nm wavelengths and transmission distance up to 120 km. In addition, these Fiber-to-Fiber media converters also support transmission between dual fiber and simplex fiber.

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Why use SM to MM fiber converters?

From the aspect of photoelectric conversion, the use of fiber converters greatly reduces the cost of fiber-to-the-home. What effect does it have on the conversion between singlemode-multimode, simplex-duplex, and different wavelengths? The following examples will illustrate the important role of fiber converters in these applications.

As we all know, when the distance between two connection points in a network system is long, we need to use singlemode fiber optic cables to transmit optical signals to ensure the normal transmission of signals. Therefore, many network service providers use singlemode fiber optic cables for transmission. Optical signals, and many devices in data centers or enterprise networks are multimode fiber ports. At this time, a device is required to achieve single mode-multimode conversion of optical signals. Campus network is such a common application. The equipment in the campus building is usually a multimode fiber port, and the connection between buildings is usually a single mode fiber optic cable. The singlemode multimode conversion function of the fiber converter has been fully implemented at this time.

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Select SM to MM fiber converter considerations?

Whether the serial fiber converter is easy to use, especially whether the networking is simple, needs to be examined from the following aspects:

1, single fiber, double fiber optional. Sometimes the optical fiber used in serial optical fiber networking is a certain optical fiber core that is distributed in the same optical cable that contains multi-core optical fibers. Obviously, using a single optical fiber core can save one optical fiber core compared to dual-core optical fibers.

2, volume and power consumption. In a complex optical fiber network, a large number of optical fiber converters are used. Therefore, the use of a small-sized optical fiber converter can greatly reduce the size of the cabinet, and a product with a low power consumption can reduce the size and cost of the power supply.

3, the versatility of the software. Is nothing to do with RS-232/RS-485 communication software, does not require settings, and is a true zero delay.

4, the versatility of single mode, multimode fiber. In many cases, serial optical fiber networking uses prefabricated fiber-optic cables, such as those used in Ethernet fiber-optic networks, and may be used for both long-distance single-mode fibers and near-distance multimode fibers.

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Conclusion

Optical fiber converters are cost-effective solutions for expanding networks such as single-mode-multi-mode, simplex-duplex, and switching between different wavelengths, and increasing optical fiber capacity. They have wide applications in optical networks. Fiber-Mart provides various types of single mode to multimode media converters, which fulfill the conversion at 850/1310nm or 850/1310/1550nm wavelengths and transmission distance up to 120 km.

What is Visual Fault Locators(VFL)?

Visual fault locator is now one of the most commonly used fiber optic testing devices to trace optical fibers, check fiber continuity and find faults such as breaks, bad splices and tight, sharp bends in fiber optic cable.

Visual fault locator is now one of the most commonly used fiber optic testing devices to trace optical fibers, check fiber continuity and find faults such as breaks, bad splices and tight, sharp bends in fiber optic cable.

Visual Fault Locator, it could be regarded to be part of OTDR and the fiber fault locator is cheap. Fiber visual fault locator is a kind of device 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. Designed with a FC,SC,ST universal adapter, this fiber testing red light is used without any other type of additional adapters, it can locates fault up to 10km in fiber cable, with compact in size, light in weight, red laser output.

Visual Fiber Optic Fault Locator is used to check, locate and patch faults on singlemode and multimode optical fibers as well as other fiber optic components. The rugged and compact design of the visual fault locator is very suitable for daily use in all fiber optic applications such as in the field, in industrial environment as well as in the laboratory.

Many of the problems encountered in troubleshooting fiber optic networks are related to making proper connections. Since the light used in fiber optic systems is infrared (IR) light, which is beyond the range of the human eye, one cannot see it. In order to solve these problems, you need a visual fault locator. Visual fault locator(VFL) is a kind of device 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.

Importance of Visual Fault Locator

The complex network integrated by optical fiber, connector and jumper makes you difficult to find the fault location. So the visual fault locator is an essential tool that quickly and easily locates problem areas in fiber cables. By pinpointing the exact location of fiber damage, technicians can diagnose, troubleshoot and fix the problem timely and efficiently. The VFL is also used for conducting continuous tests and performing fiber identification. With visual fault locator, you can easily isolate high losses and faults in optical fiber cables.

Working Principle

A powerful visible light from a red diode laser is injected into the fiber, so not only fibers  can be traced, but also high loss points can be made visible. Most applications center on short cables to connect to the fiber optic trunk cables, such as those used in premises cabling or telco central offices. The VFL works best on short cables, up to a few kilometers, thus, it covers the range where optical time-domain reflectometers (OTDRs) are not useful because of the dead zone of the OTDR.

Fiber visual fault locators include the pen type, the handheld type and portable visual fiber fault locator:

Pen type:

Pen Shape Visual Fault Locator

 

Handheld type:

handheld optical Visual Fault

Portable visual fiber fault locator:

Portable Visual Fault Locator

Comment

This basic tool is one that all installers, and maintenance personnel should have in their tool kit.  It is the most economical test tool for quickly verifying continuity, checking the validity of patch cables before or after installation, test and find breaks in LANs, verifying short lengths of installed fiber, or looking for cracked fiber in splice cases, bad connectors, tight crimps in fiber cable, backbone breaks or anywhere light continuity needs checking.

Why on earth do we need to choose active optical cable(AOC)?

AOCs bond the fiber connection inside the transceiver end, creating a complete cable assembly much like a DAC cable, only with a 3-200-meter reach capability.

What is an AOC? 

Here is the brief definition of AOC:

Optical transceivers convert electrical data signals into blinking laser light which is then transmitted over an optical fiber. Optical transceivers have an optical connector to disconnect the fiber from the transceiver. AOCs bond the fiber connection inside the transceiver end, creating a complete cable assembly much like a DAC cable, only with a 3-200-meter reach capability. AOCs main benefit is the very long reach of optical technology, while acting like a simple, “plug & play” copper cable.Active Optical Cable assemblies have been designed to support multiple protocols. Most of them are compliant with SFP+ Ethernet and InfiniBand electrical. Here is what a typical 40 Gb/s QSFP+ (Quad Small Form-Factor Pluggable Plus) AOC supports.

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Mainly, active optical cable (AOC) assemblies were invented to replace copper technology in data centers and high performance computing (HPC) applications. As we know, copper passive twinax cable is heavy and bulky, making it difficult to physically manage the datacenter. And due to the nature of electrical signals, electromagnetic interference (EMI) limits copper’s performance and reliability. Though there are so many disadvantages of copper cable, at that time, it is the main stream while the idea of AOC cables almost seems too good to be true. However, the advantages of AOC cables make the predecessors look obsolete and unsophisticated, and changes the limitation of copper passive twinax cable as well as playing an important role in high speed data transmission. Nowadays, a variety of active optical cable have been launched in the market, such as 10G SFP+ AOC40G QSFP+ to QSFP+ AOC,40G QSFP+ to 4 SFP+ breakout AOC ,40G QSFP+ to 8xLC breakout AOCs.

What are AOC Features and Advantages?

Compared to less expensive DAC cables, AOC offer:

  • Longer reach capability than DAC 3-7 meter limits;
  • 3m – 100-meters multi-mode technology;
  • 100-200 meters with single-mode, Silicon Photonics;
  • Lower weight, thinner cable and bend radius enabling increased airflow cooling and easier system maintenance.

Compared to more expensive optical transceivers, AOC offer:

  • Dramatically lower priced solution than two optical transceivers and connectorized fiber based links;
  • Lower power consumption at 2.2 Watts versus up to 4.5 Watts for optical transceivers (4-channel);
  • Lower operational and maintenance cost.

 

Fiber-Mart supplies various kinds of high speed interconnect AOC cable assemblies including 10G SFP+ AOC, 40G QSFP+ AOC Cables,100G QSFP28 AOC, 120G CXP AOC Cables. For more information, you can visit web Fiber-MART.COM.if you have something interest, pls feel free to contact us:service@fiber-mart.com

How to use an optical attenuator to test the sensitivity of a fiber optic transceiver?

Do you know how to use an optical attenuator to test the sensitivity of a fiber optic transceiver?In order to maximize the performance of our fiber optic transceivers, welcome to join our Fiber-Mart editors to see how to learn this skill.

Do you know how to use an optical attenuator to test the sensitivity of a fiber optic transceiver?In order to maximize the performance of our fiber optic transceivers, welcome to join our Fiber-Mart editors to see how to learn this skill. When the optical input power is within a certain range, the optical fiber receiver has the best performance. But how can we determine if the fiber optic transceiver will provide the best performance at the lowest optical input power? One commonly used method is to use an optical attenuator such as a diaphragm attenuator. Usually only two values are needed to complete the test. The process includes the following three steps.

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1.Use a power meter to measure the optical output power of the fiber optic transmitter. Remember that industry standards define the optical input power of transmitters and receivers for specific network standards. If you are testing a 100BASE-FX transceiver,use a 100BASE-FX transmitter and the transmitter’s optical output power should be within the manufacturer’s data sheet.

2.Connect the transmitter to the receiver and verify it is operating at the maximum optical output power available from the transmitter. You need to test the receiver with the minimum optical input power that the receiver can accept, while the receiver still provides the best performance. To do this, you need to obtain the lowest light input power value from the manufacturer’s data sheet.

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3.Calculate the level of attenuation required for the test. For example, the transmitter’s optical output power is -17 dBm, and the receiver’s minimum optical power level is -33 dBm. The difference between them is 16 dB. You can use a 16 dB bulkhead attenuator at the input of the receiver and retest the receiver. If the receiver still works, it is within specification.

Note: Light loss is not considered in the above example. Assuming the transmitter is located 10 kilometers from the receiver and the loss of the entire fiber link (including the interconnect) is 6 dB, then a 10 dB bulkhead attenuator should be used instead of 16 dB for your test.

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The optical attenuator is a very important passive optical fiber device. It can attenuate the optical signal energy according to the user’s requirements. It can also be used to test the sensitivity of optical fiber transceivers. Fiber-Mart offers a full range of optical attenuators that bring convenience to users of optical communications.Any questions welcome to communicate with us: product@fiber-mart.com.