Considerations About Optical Transceiver Designing

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. Optical transceiver plays 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 Optical Transceiver?

The optical 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.SFP-10G-SR optical transceiver

Optical Transceiver 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 optical 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 optical 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.

filter

  • 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 optical transceivers. With the three aspects mentioned above in mind, designing fiber optic transceivers should be easier. FS.COM supplies many transceivers which are fully compatible with major brands, including HP compatible transceivers (eg. J4858C).

Consider Two Things Before Deploying 10 Gigabit Ethernet

Over the years, Ethernet technologies have evolved rapidly and amazingly to meet the never-ceasing requirements of higher bandwidth and faster data transmission speeds for high quality network applications, such as live video and video download with high resolution. Through this great evolution, Ethernet technology standards have been designed, like 10 Gigabit Ethernet (GbE).

After IEEE Standard 802.3ae- 2002 for 10GbE was ratified several years ago, some enterprises have begun to deploy 10GbE in their data centers to support bandwidth-needing applications. Before deploying 10GbE, as matter of fact, there are many things that should attract your attention. Here this article lists two important things you need to consider for a reliable 10GbE deployment: 10GbE cabling choices, and 10GbE transceiver types.

10GbE Cabling Choices

Along with the technological revolution, cables used for transmission also experienced progressive development. There are two physical media available for 10GbE transmission: fiber and copper.

10GbE Fiber Cabling Choices

Fiber cables fall on two classifications: single-mode fiber (SMF) and multi-mode fiber (MMF). In SMF, there is only one path for light, while in MMF light flow through multiple paths. SMF is intended for long distance communication and MMF is used for distances of less than 300 m. Commonly used 10GbE ports designed for SMF are 10GBASE-LR, 10GBASE-ER and 10GBASE-ZR, and the ports specified for MMF are 10GBASE-SR and 10GBASE-LRM. It’s of great importance to choose these ports 10GbE transmission when link lengths matter. For example, you can choose a J9150A transceiver when the required distance is less than 300m. In a word, the form factor options depend on your link lengths.

10GbE Copper Cabling Choices

As the structured cabling techniques become mature, copper cabling technology also grasps the chance to develop itself. And more and more people start to choose copper cables as the medium for 10GbE transmission. 10GBASE-T and SFP+ direct attach cables (DAC) standards symbolize copper applications.

10GBASE-T, or IEEE 802.3an-2006, is a standard released in 2006 to provide 10Gbit/s connections over unshielded or shielded twisted pair cables, over distances up to 100 metres (330 ft). It requires the Cat 7 or Cat 6A to reach 100 meters, but can still work on Cat 6, Cat 5E, or even Cat 5 cable when reduced distances are required.

SFP+ DAC is the latest standard for optical transceivers, and it connects directly into an SFP+ housing. In SFP+ DAC cabling assembly, no optical transceiver is used at each end. A cable was invented with each end physically resembling a SFP+ transceiver, but with none of the expensive electronic components. This creation is known as DAC. Actually, besides 10GbE applications, DAC is also considered as a cost-effective solution to replace fiber patch cables sometimes in 40GbE systems. Like QSFP-H40G-ACU10M, this Cisco 40G cabling product is the QSFP to QSFP direct attach passive copper cable assembly designed for 40G links.

QSFP-H40G-ACU10M ,QSFP to QSFP direct attach passive copper cable assembly

10GbE Transceiver Types

After choosing cables, you need to select devices that connect these cables to your networks. These devices are transceivers. 10GbE has four transceiver types: XENPAK (and related X2 and XPAK), GBIC, SFP and SFP+.

XENPAK is a Multisource Agreement (MSA) that defines a fiber-optic or wired transceiver module which conforms to the 10 Gigabit Ethernet (10GbE) standard of the Institute of Electrical and Electronics Engineers (IEEE) 802.3 working group.

X2 defines a smaller form-factor 10 Gb/s pluggable fiber optic transceiver optimized for 802.3ae Ethernet,ANSI/ITUT OC192/STM- 64 SONET/SDH interfaces,ITUT G.709,OIF OC192 VSR,INCITS/ANSI 10GFC (10 Gigabit Fibre Channel) and other 10 Gigabit applications.X2 is initially centered on optical links to 10 kilometers and is ideally suited for Ethernet,Fibre Channel and telecom switches and standard PCI (peripheral component interconnect) based server and storage connections. X2 is physically smaller than XENPAK but maintains the mature electrical I/O specification based on the XENPAK MSA and continues to provide robust thermal performance and electromagnetic shielding. The 10GB X2 fiber optic transceivers series include X2-10GB-SR, X2-10GB-LR, X2-10GB-ER and X2-10GB-ZR, they are designed based on the X2 MSA and IEEE802.3ae. They’re created for the integrated systems solution provide, fiber optics distributor along with other IT distributors.

SFP+, also called SFP Plus, is short for enhanced small form-factor pluggable, an enhanced version of the SFP that supports data rates up to 16Gbit/s. SFP+ 10GbE transceiver series include SFP+ 10GBASE-SR, SFP+ 10GBASE-LR, SFP+ 10GBASE-ER, and so on. Among these types, 10GBASE-SR is widely used when the required distance is less than 500m. Say SFP-10G-SR, this Cisco 10GBASE-SR SFP+ transceiver listed in Fiberstore is designed to support 10GbE applications with the maximum distance reach of 300m.

Conclusioni

After discussion, maybe you have obtained a better understanding of 10GbE cables and transceivers, which helps you to better choose the right devices for your 10GbE applications. Fiberstore supplies various numbers of 10GbE cables and transceivers which are quality assured. For more information about 10GbE solutions, you can visit Fiberstore directly.