Category: Fiber Transceivers

DWDM technology is an extension of optical networking. DWDM devices (multiplexer, or Mux for short) combine the output from several optical transmitters for transmission across a single optical fiber. At the receiving end, another DWDM device (demultiplexer, or DeMux for short) separates the combined optical signals and passes each channel to an optical receiver. Only one optical fiber is used between DWDM devices (per transmission direction). Instead of requiring one optical fiber per transmitter and receiver pair, DWDM allows several optical channels to occupy a single fiber optic cable. As shown below, by adopting high-quality AAWG Gaussian technology, FS DWDM Mux/Demux provides low insertion loss (3.5dB typical), and high reliability. With the upgraded structure, these DWDM multiplexers and demultiplexers can offer easier installation.

A key advantage to DWDM is that it’s protocol and bitrate independent. DWDM-based networks can transmit data in IP, ATM, SONET, SDH and Ethernet. Therefore, DWDM-based networks can carry different types of traffic at different speeds over an optical channel. Voice transmission, email, video and multimedia data are just some examples of services which can be simultaneously transmitted in DWDM systems. DWDM systems have channels at wavelengths spaced with 0.4 nm spacing.

DWDM is a type of Frequency Division Multiplexing (FDM). A fundamental property of light states that individual light waves of different wavelengths may coexist independently within a medium. Lasers are capable of creating pulses of light with a very precise wavelength. Each individual wavelength of light can represent a different channel of information. By combining light pulses of different wavelengths, many channels can be transmitted across a single fiber simultaneously. Fiber optic systems use light signals within the infrared band (1 mm to 400 nm wavelength) of the electromagnetic spectrum. Frequencies of light in the optical range of the electromagnetic spectrum are usually identified by their wavelength, although frequency (distance between lambdas) provides a more specific identification.

When you’re planning a new network cable installation or considering upgrades to an existing network, you might want to consider using fiber optic cables.

Network fiber cables have some definite advantages over copper cables.

1. Greater Bandwidth

Copper cables were originally designed for voice transmission and have a limited bandwidth. Fiber optic cables provide more bandwidth for carrying more data than copper cables of the same diameter. Within the fiber cable family, singlemode fiber delivers up to twice the throughput of multimode fiber.

2. Faster Speeds

Fiber optic cables have a core that carries light to transmit data. This allows fiber optic cables to carry signals at speeds that are only about 31 percent slower than the speed of light—faster than Cat5 or Cat6 copper cables. There is also less signal degradation with fiber cables.

3. Longer Distances

Fiber optic cables can carry signals much farther than the typical 328-foot limitation for copper cables. For example, some 10 Gbps singlemode fiber cables can carry signals almost 25 miles. The actual distance depends on the type of cable, the wavelength and the network.

4. Better Reliability

Fiber is immune to temperature changes, severe weather and moisture, all of which can hamper the connectivity of copper cable. Plus, fiber does not carry electric current, so it’s not bothered by electromagnetic interference (EMI) that can interrupt data transmission. It also does not present a fire hazard like old or worn copper cables can.

5. Thinner and Sturdier

Compared to copper cables, fiber optic cables are thinner and lighter in weight. Fiber can withstand more pull pressure than copper and is less prone to damage and breakage.

6. More Flexibility for the Future

Media converters make it possible to incorporate fiber into existing networks. The converters extend UTP Ethernet connections over fiber optic cable. Modular patch panel solutions integrate equipment with 10 Gb, 40 Gb and 100/120 Gb speeds to meet current needs and provide flexibility for future needs. The panels in these solutions accommodate a variety of cassettes for different types of fiber patch cables.

7. Lower Total Cost of Ownership

Although some fiber optic cables may have a higher initial cost than copper, the durability and reliability of fiber can make the total cost of ownership (TCO) lower. And, costs continue to decrease for fiber optic cables and related components as technology advances.

When installing fibre optic cable, care must be taken to ensure that the cable is not bent, stretched or deformed. The best case is that the fibre core will break and be faulty, the worst case is that the fibre optic core will be deformed or damaged and cause signal distortion that results in intermittent faults.

Two types of fibre optic cable

In data networking, two types of cable are in common use — single mode (SMF) and multimode (MMF). The core is embedded in a layer of cladding that helps to protect and strengthen the cable.

Fibre breakage

The glass core in a fibre optic cable is fragile. It is slightly thicker than a human hair but made of glass (more rarely, a plastic material may be used for multi-mode). Manufacturers have been able to design and manufacture the core material to be somewhat elastic and resilient to bending. Single mode fibre uses a special type of glass that is extruded into a solid medium to protect it. MMF is made from glass but being thicker (at 50 µm compared to 9 µm), is more robust. Because of this, SMF is more sensitive to breakage than MMF.

When the core is stretched or bent beyond a certain point, the core will physically break into two parts. The cladding and buffer around the cable core helps to prevent damage. The glass core has some space to protect against movement, thermal expansion/shrinking, and for installation.

When the cable’s physical integrity is compromised, two outcomes are possible. The best case is that two pieces of the core are not physically aligned and no laser light will propagate. Something that is broken can be located and fixed.

A less common case is that core materials will be partially aligned after the break and pass a partial signal. The network may or may not work due to the drop in laser power.

Intermittent operation may occur as the cable expands/shrinks with temperature, vibration or movement and the core loses alignment or the gap expands to reduce laser power to a non-functional level.

A fibre optic cable relies on complete internal reflection — and this scenario still supports that — but a substantial amount of signal power can be lost at this interface, plus reflections at the break/air interface will have secondary effects.

Cracking of the fibre core

It is also possible that the fibre core might be damaged instead of broken. For SMF, the glass might only crack and cause imperfection in the medium, which would reduce signal propagation and cause reflections. MMF is more likely to be damaged by flexing and cause power loss. In the case of graded fibre, this is quite damaging to the signal as it will be badly distorted.

Best and worst cases

When working with fibre optic patch leads, it is common for people to trap them in doors or stretch them by pulling on them. While patch leads are designed to be more flexible compared to the cabling used in risers, they are still susceptible to breakage in the best case. Best case means that the cable doesn’t work; worst case is when the fibre core is partially damaged and likely to cause intermittent operation.

Intermittent is much worse than broken. Another reason for replacing cables is that the fibre connectors are dirty, scratched or faulty and new cables will improve the power level received. Cleaning the cables and SFP (Small Form-Factor Pluggable) connectors can also resolve intermittent problems.

In my opinion, that’s why replacing the cable often fixes intermittent problems in a network. It is very hard to test or confirm a faulty fibre optic patch lead. A faulty patch lead can cause waveform deformation through propagation distortion or power loss through a cracked or misaligned core. And according to the temperature fluctuation, ambient vibration by fans and coolers, or just being moved, the network might have problems.

The image below shows a fibre optic patch where the rack door has been pressing on the patch where the strain relief ends, and rather obviously, the bend radius has been severely compromised. While patch cables are fairly robust, this cable is faulty when the door is closed but working when the door is open.

That’s worse than just broken.

The CWDM are by and large in view of thin coat channel innovation which is the type of item fall under the WDM class. There arrived in a total scope of Class-8 CWDM Mux-Demuxand also OADM that stands for Optical Add Drop Multiplexer units with a specific end goal to meet a wide range of necessities and system arrangements.

Likewise, it has across the board applications that require the Channel CWDM. Some of them include: Gigabit and 10G Ethernet, Fiber Channel, ATM, ESCON, in Metro total, SDH/SONET, and CATV and so forth. Presently, we should talk about the accompanying components and utilizations of Channel CWDM that settle on it an ideal decision for all. The CWDM Mux / Demux items give up to 16-channel or even 18-channel Multiplexing on a solitary fiber. Standard CWDM Mux/Demux bundle sort include: ABS box bundle, LGX pakcage and 19″ 1U rackmount.

Highlights

The loss of insertion quality creates from the presentation of a gadget into the optical fiber is by and large lesser in CWDM than alternate gadgets; this produces short inclusion costs.

Channel-8 CWDM is dependably very steady and solid in the meantime. Not at all like every other sort of WDM class, the Channel CWDM has higher dependability.

The CWDM items are typically Epoxy free on optical way; this prompts better working and Epoxy free condition while the execution.

In CWDM, the channel segregation is very high. This expanded seclusion prompts better and successful outcomes.

Applications

WDM and Access Organize: As these channel sorts are the piece of WDM class, these have their best application in the WDM and also Access systems.

Line Observing: These items have their incredible use in line checking. This guarantees there is no crash on a similar line of some other range or frequency.

Cellular Application: The CWDM channel arrangements have their utilizations and applications additionally in the Cellular area, and advances as the unequaled panacea for some different parts and ventures.

Telecommunication: The broadcast communications devours Channel-8 CWDM at an incredible rate. It needs to utilize these items for the straightforward transmission of signs and utilization of the filaments for the same.

Aside from every one of the elements and applications, the capacity of CWDM is additionally to unravel the deficiency of fiber and straightforward transmission of exchange while lessening the charges of system building. This is the motivation behind why the Channel CWDM and LGX CWDM Mux and DeMux Module have a matter of extraordinary heights in the realm of fiber optics, flag transmission and multiplexing and so forth.

A WDM (Wavelength Division Multiplexing) is a system that uses a multiplexing (at the transmitter) and a demultiplexer (at the receiver) for the completion of the process and transmission of the signals.

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

CWDM stands for Coarse Wavelength Division Multiplexing, and DWDM is the acronym for Dense Wavelength Division Multiplexing. Whether DWDM or CWDM, both are the types of WDM mechanism and have an array of differencess.

Let’s get acquainted with the chief difference between CWDM and DWDM:

The Coarse WDM has less than 8 active wavelengths per optical fiber whereas the DWDM has more than 8 active wavelengths per optical fiber.

The CWDM has lower capacity strength and hence is low in costs; conversely the DWDM possesses high capacity –this leads to an augmented price which is worth its qualities.

When it comes to the difference between the distance of the two, the CWDM has short range communication because the wavelength is not amplified, and DWDM has long range communication.

CWDM Mux and Demux systems are developed to be used in multiplexing multiple CWDM channels into one or two fibers.

Another major difference is that DWDM systems are made for longer haul transmittal, by keeping the wavelengths closely packed. Also, a DWDM device can transmit more data over long distances and to a significantly larger run of cable with lesser interference than a comparable CWDM system which has a shorter haul transmittal.

Furthermore, the Dense Wavelength Division Multiplying systems are capable to fit more than forty different data streams in the amount akin to that of fiber used for two data streams in a CWDM system.

Apart from all the difference there is one more and that is wavelength drift is possible in CWDM, but when it comes to the DWDM –precision lasers are needed to keep channels on the target.

Beyond being different from each other –these systems play different roles in the effective transfer of the signals, and thereby both are important enough.

Mayday, mayday. We have a problem! We have two switches who desperately want to talk to each other but the walls of their switch cabinets are restricting conversation and they are located 7 feet away from each other. Luckily there is a transceiver that can help us out: the small form-factor pluggable.

The small form-factor pluggable (SFP) is a compact, hot-pluggable transceiver used for data communication applications.  These small metal devices plug into a special switch slot and support communication over either fiber optic or copper networking cable.

Types

To select the right transceiver, you will need to base it on the type of cable you are using, copper or fiber.  To communicate over fiber optic cable, make sure you select a transceiver that matches the slot bandwidth and speed of the device you are connecting to (1Gbps or 10Gbps) and your cable’s connector type (LC or SC). To communicate over copper, select a transceiver with an RJ-45 Ethernet port. Some transceivers support specialty applications such as Infiniband (sometimes used in high-speed storage networks). Make sure you understand your application requirements first, then select your transceiver accordingly.

Optical Transceiver options

GBIC- Originally named Gigabit Interconnect. Typically used for the Cisco 2900 & 3900 series switches, 10/100 megabit.

SFP- Originally named Small form factor pluggable. Commonly used for the Cisco Catalyst 3560 & 3760 series switches amongst others. These SFPs will support Gigabit uplink connection

SFP+- Higher throughput with an enhanced version that will give you 10G uplink capability.  Commonly used for 3560x & 3750x series switches amongst others.

Benefits & Why You May Need One

These SFP transceivers are hot-swappable and have the capability to allow modifications which can be added after the initial purchase. These transceivers can also be deployed in “mix-use” environment of single-mode/multi-mode SFPs and a variety of hardware providing a flexible and customizable solution. If you are looking to have your switches communicate at a faster rate, installing an SFP may be useful. If you are looking for a little more speed in your transfer rates, you will need to have a switch or expansion module that supports 10GbE to use a 10GbE SFP+ transceiver, but not all switches/modules support that.

From the looks of it, these SFP’s fits the bill for all of our switches and/or routers to communicate with each other. If you are in the market to buy any type of SFP, check out CablesAndKits as we offer a variety of options from Cisco Original, and compatible options.