Patch Cable Selection Guide to Fiber Optic Transceivers

petak , 13.05.2016.

Nowadays, a huge number of bandwidth-hunger devices are housed in data centers, like clustered storage systems, backup devices, and various servers, which are all connected by networking equipment. These devices need reliable and scalable cabling structure for high performance and flexibility. For some large- or middle-sized enterprises, their billion-dollar business lie in the suitable deployment of fiber patch cords and fiber optic transceivers. Since there are many kinds of patch cables available in the market for transceiver modules to promote data transmission in enterprises’ data centers, it seems a little difficult to choose the right kind for such transceivers. This text tackles this issue and provides some selection guide.

When delve into this topic, it’s imperative to have a basic understanding of the fiber optic transceiver.

Fiber Optic Transceiver Basics
Fiber optic transceiver, just as its name replies, is a self-contained component that can both transmit and receive signals. In most cases, this transceiver is plugged in devices such as routers or network interface cards which offer one or more transceiver module slot. In its whole signal transmission process, the transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant. The light from the end of the fiber is coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment.

According to different protocols, a wide range of optical transceivers are designed to support different data rates, including Gigabit SFP transceiver, 10G SFP+ transceiver, 40G QSFP+, etc..Take MGBBX1 for example, this Cisco 1000BASE-BX-U SFP is designed to be applied in Gigabit Ethernet (GbE) applications.

Fiber Patch Cord Details
Fiber optic patch cord, also called fiber jumper or fiber optic patch cable, consists of fiber optic cable terminated with different connectors on the ends. It’s typical application includes computer work station to outlet and patch panels or optical cross connect distribution center. While selecting patch cord, it’s recommended to take on from the following aspects, fiber cable mode, cable structure, connector types and so on.


Single-mode/Multi-mode Patch Cord
It’s known that fiber patch cords can be classified into single-mode and multi-mode fiber patch cord based on cable mode used. Single-mode patch cords, usually in yellow color, are with 9/125 fiber glass and has only one pathway for signal transmission, while multi-mode ones, often in orange, are with OM1 62.5/125 or OM2 50/125 fiber glass, and allow multiple pathways and several wavelengths of light to be transmitted with the large core.

Simplex/Duplex Patch Cord
According to the cable structure, patch cord can be divided into simplex and duplex versions. Simplex, also known as single strand, patch cable has one fiber, while duplex cable has two fibers joined with a thin web. Both simplex and duplex patch cords are available in single-mode or multi-mode versions. Because simplex patch cord has only one fiber link, its typically deployed for applications that only require one-way data transfer. For those applications, like fiber switches and servers, it’s advised to select duplex fiber optic cable for simultaneous and bidirectional data transfer. Additionally, there is also ribbon fan-out cable assembly (ie. one end is ribbon fiber with multi fibers and one ribbon fiber connector such as MTP connector (12 fibers), the other end is multi simplex fiber cables with connectors such as ST, SC, LC, etc.).

Patch Cord With Different Connectors
By connector type standard, fiber patch cord can also be divided. For instance, LC fiber patch cable is named as it is with LC connector. Similarly, there are SC, ST, FC, MT-RJ, E2000, MU and MPO/MTP fiber patch cables. Additionally, there are PC, UPC, APC type fiber patch cords, which are differentiated from the polish of fiber connectors.

How to Select Right Patch Cord for Transceiver?
After respective introduction to fiber optic transceiver and fiber patch cord, let’s go to the core issue—to choose the suitable cable type for transceivers.


In this part, I will take Cisco transceiver modules for example. For example, I need the suitable cable type for these two Cisco GbE transceiver modules, GLC-EX-SMD and MGBLX1. Then how to choose the right type? According to “Cisco Gigabit Ethernet Transceiver Modules Compatibility Matrix”, GLC-EX-SMD is the 1000BASE-EX SFP module that works through single-mode fiber (SMF) with LC duplex, and MGBLX1 is the 1000BASE-LX SFP module also for SMF with LC duplex. In such a case, since both two modules operate on SMF with LC connector, what I need is the with LC-LC duplex single-mode patch cable.

Conclusion
The above-mentioned example just lists one patch cable type for fiber optic transceivers. There are several commonly-aused patch cable types: LC-LC Simplex 9/125 Single-mode Fiber Patch Cable, LC-SC Duplex 9/125 Single-mode Fiber Patch Cable, LC-LC Duplex OM1 62.5/125 Multi-mode Fiber Patch Cable, ect.. Fiberstore supplies various kinds of high-quality patch cords for transceiver modules. You can visit Fiberstore for more information about patch cords.

Oznake: fiber patch cords, fiber optic transceiver, SFP, MGBBX1, MGBLX1

Considerations About Fiber Optic Transceiver Designing

utorak , 22.03.2016.

The rapid expansion of fiber optic networks, including data services measured by data volume or bandwidth, shows that fiber optic transmission technology is and will continue to be a significant part of future networking systems. Network designers are becoming increasingly comfortable with fiber solutions, since the use of which allows for more flexible network architecture and other advantages, such as EMI (Electromagnetic Interference) resilience and data security. Fiber optic transceivers play an really important role in these fiber connections. And while designing fiber optic transceivers, three aspects need to be considered: environmental situation, electrical condition and optical performance.

What Is a Fiber Optic Transceiver?
The fiber optic transceiver is a self-contained component that transmits and receives signals. Usually, it is inserted in devices such as routers or network interface cards which provide one or more transceiver module slot. The transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant. Then the light from the end of the fiber is coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment. There are a full range of optical transceivers available in telecommunication market, like SFP transceiver, SFP+ transceiver (eg. SFP-10G-SR shown below), 40G QSFP+, 100G CFP, etc.

Designing Considerations
It’s true that fiber links can handle higher data rates over longer distances than copper solutions, which drive the even wider use of fiber optic transceivers. While designing fiber optic transceivers, the following aspects should be taken into consideration.

Environmental Situation
One challenge comes to the outside weather—especially severe weather at elevated or exposed heights. The components must operate over extreme environmental conditions, over a wider temperature range. The second environmental issue related to the fiber optic transceiver design is the host board environment which contains the system power dissipation and thermal dissipation characteristics.

A major advantage of the fiber optic transceiver is the relatively low electrical power requirements. However, this low power does not exactly mean that the thermal design can be ignored when assembling a host configuration. Sufficient ventilation or airflow should be included to help dissipate thermal energy that is drawn off the module. Part of this requirement is addressed by the standardized SFP cage which is mounted on the host board and also serves as a conduit for thermal energy. Case temperature reported by the Digital Monitor Interface (DMI), when the host operates at its maximum design temperature, is the ultimate test of the effectiveness of the overall system thermal design.

Electrical Condition
Essentially, the fiber transceiver is an electrical device. In order to maintain error free performance for the data passing through the module, the power supply to the module must be stable and noise-free. What’s more, the power supply driving the transceiver must be appropriately filtered. The typical filters have been specified in the Multisource Agreements (MSAs) which have guided the original designs for these transceivers. One such design in the SFF-8431 specification is shown below.


Optical Performance
Optical performance is measured as Bit Error Rate, or BER. The problem facing designing optical transceiver lie in the case that the optical parameters for the transmitter and receiver have to be controlled, so that any possible degradation of the optical signal while traveling along the fibers will not cause poor BER performance. The primary parameter of relevance is the BER of the complete link. That is, the start of the link is the source of the electrical signals which drive the transmitter, and at the end, the electrical signal is received and interpreted by the circuitry in the host by the receiver. For those communication links which use optical transceivers, the primary goal is to guarantee BER performance at different link distances, and to ensure broad interoperability with third party transceivers from different vendors.

Conclusion
Fiber technology is becoming maturer, leading to the wider use of fiber optic transceivers. With the three aspects mentioned above in mind, designing fiber optic transceivers should be easier. Fiberstore supplies many transceivers which are fully compatible with major brands, including HP compatible transceivers (eg. J4858C). For more information about fiber optic transceivers, you can visit Fiberstore.

Oznake: fiber optic transceiver, SFP, SFP-10G-SR, compatible transceivers, J4858C