Category: Fiber Transceivers

Optical transceivers, Active Optic Cables, data center switches, and cable management in data centers.

Multi-fiber Connectors for High Port Density

As the introduction of multimode optical fibers of the categories OM3 and OM4 are used for implementing 40 GbE and 100 GbE, though the small diameter of the optical fibers poses no problems in laying the lines, the ports suddenly have to accommodate four or even ten times the number of connectors. This large number of connectors can no longer be covered with conventional individual connectors. Thus, some vendors such fiber-mart.com start to provide the incorporated optical connectors with very low loss for high port density. This article talks about MPO connectors and its high performance connector –MPT connector.
The MPO connector is short for multi-fiber push on. It’s defined according to IEC 61754-7 and TIA/EIA 604-5 that can accommodate up to 72 fibers in the tiniest of spaces, comparable to an RJ45 connector. MPO connectors are most commonly used for 12 fibers (Figure 1).
MPO Connector Benefits
MPO connectors deliver the optical, mechanical and environmental performance that service providers need to expedite the addition of fiber capacity and to support higher data-rate services. Among the numerous operational, financial and competitive benefits of using MPO connectors in the core network are:
Optical insertion loss and return loss performance similar to single-fiber connectors
Maximum space savings for high-density fiber environments
Reduced labor costs via fast, easy installation– because one 12-fiber MPO connector replaces 12 single fiber connectors
Compliant with standards, i.e., IEC 61754-7; IEC 61755-3-31, IEC 61753-1
However, the fibers are usually glued into holes within the ferrule body. Fibers glued directly into the body with MPO connectors make reworking later on difficult and put limits on manufacturing accuracy. And there will be some angle errors and radial displacement. So MTP connectors different from the MPO in various ways. e.g. rounded pins and oval shaped compression springs are created to prevent scratches during plug-in and protect the fibers in the transition area from connector to cable.
The MTP connector (Figure 2) is a high performance MPO connector with multiple engineered product enhancements to improve optical and mechanical performance. The MTP connectors are compliant with all MPO connector standards including IEC-61754-7.
MTP Connector Benefits
The MTP connector has benefits that generic MPO connectors don’t have. And they are as follows:
1. The MTP connector housing is removable. So you can rework and re-polish the MT ferrule, change the gender after assembly and scan the ferrule interferometrically after assembly.
2. The MTP connector offers ferrule float to improve mechanical performance. This allows two mated ferrules to maintain physical contact while under an applied load.
3. The MTP connector uses tightly held tolerance stainless steel guide pin tips with an elliptical shape. The elliptical shaped guide pin tips improves guidance and reduces guide hole wear.
4. The MTP connector spring design maximizes ribbon clearance for twelve fiber and multi-fiber ribbon applications to prevent fiber damage.
5. The MTP connector is offered with four standard variations of strain relief boots to meet a wide array of applications.
MPO/MTP connectors play an important role in the multi-fiber connection system. The connectors ensure fiber alignment when mating and realize high density interconnection. MPO/MTP connectors save time and reduce the risk of damaging fragile optical connectors.

General Understanding of LC to LC Fiber Optic Cables

Fiber optic patch cords are also known as fiber optic jumpers or fiber optic patch cables. Fiber optic patch cords are designed to provide optical connection for fiber networks within structured cabling systems. It’s a quick and easy method for routing fiber patches in data centers, head-ends, cellular hubs and central offices. It’s composed of two parts: optical connector and fiber optic cable. As to the connector, fiber patch cords could be terminated with LC/SC/ST/FC/MTRJ/MU/SMA connectors on both ends.
With the increasing deployment of fiber in the LAN, the need for small form factor fiber optic connectors is becoming urgent. The main reasons are deployment cost and space savings for cabling hardware and equipment interfaces. LC connector is a small form factor connector with half size of SC connector. The connector was invented by Lucent Technologies. Lucent is an American multinational telecommunications equipment company. So LC stands for Lucent Connectors. The connectors are made to support Telecom and Datacom networks.
The LC fiber patch cable is with a small form factor connector and suitable for high density applications. It’s compliant with IEC, Telcordia, EIA/TIA. One of the fiber optic patch cords LC series is LC to LC fiber patch cord. LC to LC fiber patch cord includes LC-LC single-mode and LC-LC multi-mode types.
LC-LC single-mode has two versions like simplex and duplex. Single-mode simplex fiber cable is single strand and single-mode duplex fiber cable is zipcord cable which is tight-buffered and jacketed. To be easily identified, the color of the cable jacket is often yellow. And the diameter is usually 1.8mm, 2mm or 3mm. The LC-LC single-mode fiber optic cables have the features of good performance and fast delivery. It’s used for long distance transmission.
LC-LC multi-mode patch cords are composed of a polymer outer body and inner assembly fitted with a precision alignment mechanism. As single-mode patch cords, this kind has both simplex and duplex versions too. These cables are with typical 50/125 and 62.5/125 optional multi-mode fiber. The cable diameter is 0.9mm, 2mm or 3mm. Due to the thick core size, the signal degradation caused by the refraction occurs. Thus it’s usually used for short distance signal transmission.
LC to LC fiber optic cables, as one kind of fiber optic patch cords, have many advantages such as high return loss, low insertion loss and back reflection loss, good durability, high temperature stability, good interchangeability and duplication. Thus they are widely used in Gigabit Ethernet and fiber channel, multimedia, telecommunication, and high speed data transmission throughout the network, etc.

Should We Use Third-Party Compatible SFP Transceiver?

Many customers tend to use third-party compatible Cisco SFP transceivers to save costs on these expensive modules. But there maybe a problem that the Cisco’s new line switches do not support third-party SFPs. When inserting an SFP transceiver into Cisco switches to connect network backbone, you will find it doesn’t match an official Cisco product. Then you will stumble across the following error:
%PHY-4-UNSUPPORTED_TRANSCEIVER: Unsupported transceiver found in Gi1/0/0
%GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port 65538 has bad crc
The Catalyst switch disables the GBIC port. That’s because Cisco Catalyst switches are configured by default not to work with non -Cisco SFPs. When a third-party SFP inserted into the port, the switch immediately recognize it doesn’t match. And it will throw the above error message and disables the port.
Except the error, Cisco tends to be very strict about the warranty requirements for the third-party components including SFP transceivers. The details are as following: When Cisco determines that a fault or defect can be traced to the use of third-party transceivers installed by a customer or reseller, then, at Cisco’s discretion, Cisco may withhold support under warranty or a Cisco support program. In the course of providing support for a Cisco networking product Cisco may require that the end user install Cisco transceivers if Cisco determines that removing third-party parts will assist Cisco in diagnosing the cause of a support issue.
That means if you use a third-party transceiver and it causes actual damage. Cisco may refuse warranty support. If the transceiver is merely suspected of being at fault, they may refuse support until you install a supported Cisco-branded transceiver.
Now you may ask “Are the third-party compatible transceivers safe?”. The answer is yes. Most third-party transceivers are made and assembled in exactly the same plants assembling officially-branded transceivers. In a matter of speaking, an official Cisco transceiver and a third-party transceiver are the same, aside from the branding. In fact, the transceivers don’t have any real way of failing that would also damage a switch. So there is no problem to use third-party compatible transceiver.
Compatible SFP transceiver modules offered by fiber-mart.com are third-party and fully compatible with major brands (Cisco, HP, NETGEAR, Finisar, Juniper, etc.) and backed by a Lifetime Warranty. fiber-mart.com have a large selection of compatible SFP modules in stock and can ship within 24 hours.

 

Copper SFP Transceiver for 1000BASE Applications

In the past, because of low cost and compatibility with existing LANs, 100Mb/s Ethernet was very popular. As people’s increasing demands for faster delivery of information, high bandwidth Ethernet LAN is evolving. 1000BASE (1 Gbps Gigabit Ethernet) came around and brought Ethernet technology to a new stage. Gigabit Ethernet, as the new networking techology was a viable solution for increased bandwidth requirements. Early implementation of the technology will be in high-speed backbones and specialized workgroups. The initial standards of 1000BASE were created and maintained by the 802.3z working group of the IEEE LAN-MAN Standards Committee in June 1998.
Now that 1000Mb/s Ethernet has been applied generally, the corresponding equipment like the cable and transceiver are needed to make the network the most effective.
Before 2000, SFP optical transceiver module combines transmit and receive functions in a compact, low power, low cost package format. Now it’s widely applied in Fibre Channel, Gigabit Ethernet (GbE), and SONET/SDH and supports data rates between 125 Mb/s and 4 Gb/s. Later some manufacturers make SFP ports with copper transceivers. The copper small form factor pluggable (SFP) transceiver can maintain both configuration flexibility and high port utilization with low cost for optical networks. Due to these advantages, the need for copper SFP transceivers increases obviously.
Configuration Flexibility with High Port-level
When there is no copper transceiver, users who want to support Ethernet traffic over both copper and fiber should offer two different line cards dedicated to one media or the other or, alternatively, hybrid cards with a fixed number of copper ports and optical cages. But this way is not very efficient because the available ports for each type of media rarely matched the network’s constantly evolving topologies.
In today’s network environments, systems must deal with the ongoing convergence of data, voice, and video traffic as well as topologies that mix Internet Protocol (IP) with legacy PDH traffic and integrate specialized requirements such as Fibre Channel or ATM. As GbE switches, routers, and multi-service provisioning platforms (MSPPs), for example, must provide port-level flexibility for handling both fiber and copper interfaces, thus copper SFP transceiver becomes the best way to optimize port-level flexibility.
A Cisco copper SFP and an optical SFP provide exactly the same physical and electrical interface for any port on the line card. This just needs a single line card design that can handle the entire spectrum of copper and fiber connections. The port utilization copper SFP transceiver can more efficiently to accommodate the changing network requirements.
Low Cost
The traditional dedicated line card approach increases inventory costs because it has low level of field reconfiguration. Copper SFP transceiver and a common line card design for all ports clearly reduce the inventory costs as well as complete the copper to fiber reconfiguration.
All in all, copper SFP transceiver has the advantages such as increased port density, improved system utilization, and low overall costs. Copper SFP transceiver offers users a level of flexibility that did not exist before. So Copper SFP transceiver will still gain its popularity.

How to Install and Remove a SFP Transceiver?

SFP is short for small form-factor pluggable. It’s a compact, hot-pluggable transceiver used for telecommunication and data communications. The form factor and electrical interface are specified by a multi-source agreement (MSA). It interfaces a network device motherboard (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable. SFP transceivers can support SONET, Gigabit Ethernet, Fibre Channel, and other communications standards. SFP transceivers are upgraded from the traditional version with more flexibility but a smaller size.
Sometimes you may encounter the affairs like the installation and removing of a SFP transceiver. The following will tell you how to install and remove a SFP transceiver.
Install a SFP Transceiver
The following steps tell how to install a SFP transceiver:
Attach an ESD-preventive wrist strap to your wrist and to the ESD ground connector or a bare metal surface on your chassis. SFP modules are static sensitive. Wear an ESD-preventive wrist strap so that it can prevent ESD damage.
Remove the dust cap and save for future use.
Ensure the SFP transceiver in the correct orientation for your device.
Insert the SFP module into the socket. Be sure that the SFP module is in the right position before inserting.
Observe the LED. If the LED turns green, it means the transceiver and the device establishes link successfully. While if the LED is off, there may be an installing problem with the adapter.
Remove a SFP Transceiver
To remove a SFP transceiver (see the picture), the following procedures you should bear in mind:
Attach an ESD-preventive wrist strap to your wrist and to a bare metal surface on the chassis.
Disconnect the network cable from the SFP transceiver.
Remove the SFP transceiver carefully from the module slot.
Place the removed the SFP module in a static shielding bag.
The above is about how the installation and removing of a SFP transceiver. One of the most famous brands Cisco SFP transceiver, which offers a convenient and cost effective solution in the adoptions of data center, campuses, metropolitan area, ring networks and storage networks is also suitable to these steps in applications.
At last, SFP transceivers are dust sensitive. So store the devices with plugs to avoid getting dust into the installed optical bores. And clean the optic surfaces of the fiber optical cables before the insertion. But you should better not insert or remove a SFP module until it’s necessary. Because it’s not good for keeping the useful life with repeated removals or insertions of a SFP transceiver.

What Does DOM Mean for a SFP Transceiver?

If you take a look at the description of a SFP transceiver module, you will see the “DOM support” appeared in the product details. What does it mean? In fact, DOM or Digital Optical Monitoring as the words implies, is used for monitoring some parameters of the transceiver, which can help to identify the location of the fiber link failure, simplify maintenance, improve system reliability. Obviously a SFP with DOM function is high-ender than one without it. This is why most of modern optical SFP transceivers support DOM functions. To have a further understanding of DOM, some detailed information will be introduced in the following passage.
What Is DOM Support?
As noted before, DOM is a feature allowing users to monitor parameters of the transceiver module in real-time, such as temperature, supply voltage, laser bias current as well as transmit and receive optical power. Measurement of these parameters can help network administrators to check and ensure that the module is functioning correctly. Nowadays SFP transceivers are using DOM to perform transceiver monitoring and troubleshooting operation. For example, the DOM function that Cisco GLC-SX-MMD transceiver support can assist network designers in detecting and digitizing parameter signals on circuit board in the inside of this Cisco SFP module. But how to generate DOM function for your optical transceiver?
How to Use DOM
In order to be able to take advantage of DOM capability, both the device and the platform must support the feature. When the transceiver module is DOM-enabled, a minimum software version may be required to support the feature in each platform. And there are five steps you should follow when conducting the DOM function in a SFP module.:
1. Enable example: Router> enable (Enables the privileged EXEC mode. Enter your password if prompted.)
2. Configure terminal example: Router#configure terminal (Enters the global configuration mode.)
3. Transceiver type all example: Router (config) #transceiver type all (Enters the transceiver type configuration mode.)
4. Monitoring example: Router (config-xcvr-type) #monitoring (Enables monitoring of all optical transceivers.)
5. Monitoring interval example: Router (config-xcvr-type) #monitoring interval 500 ((Optional) Specifies the time interval for monitoring optical transceivers. Valid range is 300 to 3600 seconds, and the default value is 600 seconds.)
To sum up, these three commands can used to turn on/off DOM for all transceivers type in the system:
Router (config) #transceiver type all
Router (config-xcvr-type) #monitoring
Router (config-xcvr-type) #end
Once enabled, DOM can be accessed via CLI using “show interface transceiver command”. Off all the five values, two mostly used and relevant values are TX and RX power, temperature is also used sometimes. The operating range of these three values is unique across all modules and is available in the data sheet.
Additional Information
DDM and RGD are another two common abbreviations appeared in transceiver modules’ product specifications. So, what does they refer to?
DDM, short for Digital Diagnostics Monitoring, is a technology used in SFP transceivers in order to give the end user the ability to monitor real-time parameters of the SFPs. Such parameters include optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage etc.
What Is a ‘Rugged’ (RGD) Transceiver Module?
These are enhanced transceiver modules which have been designed for greater durability, and can operate under more extreme conditions. Rugged transceivers may feature enhanced ESD protection, and extended operating temperature range. Rugged transceiver modules often have “-RGD” in their product number to assist in their identification.
Conclusion
After going through this passage, you may have a better understanding of DOM. Before purchasing the SFP transceiver, you should read all the product details carefully because not all the transceivers can support DOM like GLC-LH-SM. Find a reliable vendor will avoid those problems. Fiberstore, as a professional telecommunication manufacturer, is aimed at providing first-class online service and high-quality products to all customers. Our SFP modules are fully compatible with Cisco, Huawei, ZTE, HP, Jumper and other brands. If you have any requirement about our products, please contact us directly.