Tag: transceiver

Transceiver Selection Guide for Your Networking Use

by http://www.fiber-mart.com

Thanks to the advances made in fiber optical technologies, fiber solutions have been deployed in ever-increasing applications where high-speed and high-performance data transmission is needed. They outweigh the copper solutions in such aspects as higher bandwidth, longer distances and Electromagnetic interference (EMI) immunity. Transceivers, one of the key components required in such fiber connections for high networking performance, have experienced the never-ceasing industrial designs, from lower port density to higher, from the standard modules to the final hot-plable ones, to meet the ever more flexible networking infrastructure.
There is a broad selection of hot-plable transceiver modules available for fiber networking use, and you may feel a little confused about how to select the correct transceivers for your networking transmission. In this article, I will illustrate different aspects of transceivers that need to be known before choosing a transceiver.
Transceiver Basics
Before giving guidance to transceiver selection, it’s necessary to know the basics of transceiver. Transceiver is a combination of a transmitter and a receiver in a single package, while they function independently for bidirectional communication. Typically, a fiber optic transceiver converts the incoming optical signal to electrical and the outgoing electrical signal to optical. More specifically, 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.
Here go the several aspects of transceivers that are helpful in your purchasing.
Form-factor
Multi-source agreements (MSAs) between different equipment vendors specify guidelines for electrical and optical interfaces, mechanical dimensions and electro-magnetic specification of a transceiver. The equipment vendors follow these MSA defined values for designing their systems to ensure interoperability between interface modules. The form-factor or the MSA-type is needed so that the transceiver can mechanically and electrically fit into a given switch, router, etc. Transceiver MSAs define mechanical form factors including electric interface as well as power consumption and cable connector types. There are various MSA types: SFP (eg. MGBSX1), SFP+, XFP, CFP, CFP2, CFP4, QSFP and so on.
Transmission Media
Transceivers can work over single-mode fiber (SMF), multi-mode fiber (MMF), and copper. In different Ethernet applications, media can achieve different link lengths when combined with transceivers. Take Gigabit Ethernet (GbE) applications for example, single-mode transceivers can have a transmission distance of 5km to 120km, while multi-mode transceivers are defined to have the maximum reach of 55om, with copper solution establishing even fewer link length at 25m. Take MGBLX1 for example, this Cisco compatible 1000BASE-LX SFP works through SMF for 10km reach.
Power Budget
The transceiver power budget is the difference between transmitter launch power and receiver sensitivity and has to be 2-3dB larger (Margin) than the measured link loss. If the link loss cannot be measured, it has to be calculated. Therefore transmission distance [km], the number of ODFs, patches and passive optical components (Muxes) have to be known. Common values for power budget are <10, 14, 20, 24, 28, >30dB.
If you’re seeking high-speed data carrier, transceivers can help accomplish goals. By transmitting data at 10Gbit/s, 40Gbit/s, 100Gbit/s or 12940Gbit/s, they can ensure that data arrives quickly. Transceiver modules that are capable of handling fast speeds can help with downloads and high and low bandwidth video transmission.

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.