#St connector fiber Patch

#St connector fiber Patch

Considering how many patch connections may be required from the source through an equipment rack patch bay, routers, and the workspace, the loss budget can escalate rapidly. Endfaces become highly reflective at very high transmission rates and require special treatment such as angle polishing or spherical polishing to minimize loss effects.īut, to be specific on the connector loss budget, nominal connector interface loss may range from about 0.1 dB to as much as 1.5 dB per connection under expected installation conditions. The escalation of high-speed laser fiber transmission design poses a new concern for the endface design of fiber terminations. While the interruption of the light path alone represents a certain signal loss at the interface due to inexact mating of the optical fiber ends, other anomalies such as poor surface condition of the fibers and non-parallel end surface alignment may exist that drastically increase losses beyond the anticipated level. Connector interface loss is also specified in dB. The idea behind a good fiber connector, of course, is to minimize interface losses between the connected fibers, thus keeping within a loss budget that provides system reliability over long time periods. Often, the largest initial loss occurs at the output coupling of the source followed by the first system patch encounter. In either case, each connector interface encountered by the distributed signal has a measurable loss associated with it. For multi-kilometer-realm distributions, multimode fiber dispersion can become significant, whereupon the use of lower loss singlemode fiber may be dictated. In fact, increased light dispersion, another form of loss discussed in my previous article, usually overshadows fundamental attenuation loss. For fiber cabling in AV applications under about 1,000 feet, the cable loss may be easily less than 3 dB. Just the opposite may be true in most fiber installations. In other words, the ohmic loss due to connector contact resistance is usually negligible compared to the overall cable loss. For copper circuits, digital or analog, the loss budget for connectors is typically assumed to be “zero” for all practical purposes. Optical power, like electrical power, is commonly measured in dB with -3 dB, relative to the source's reference level, representing the half-power point. Depending on choices made, cumulative connector interface signal losses could exceed the loss realized in the fiber cable itself! Keeping a Loss Budget Although fiber cable losses do escalate depending on the type and quality of fiber installed, each connection point imparts a definitive loss.

In other cases, the choice of connectivity for most or all of the fiber distribution may rest with you. Perhaps the fiber transmission equipment itself will dictate connectivity.

Ultimately, questions about the physical connection must be answered. Whereas copper connections rarely have a significant signal loss impact in AV applications, fiber connections do have measurable impact at each interface point within a distribution system. Unlike the steadfast, ubiquitous BNC connector used for copper coaxial wiring in AV, fiber connectors are evolving with the maturity of fiber technology.

In this issue, we will look at the Subscriber Connector - SC, Straight Tip- ST, Fixed Connection - FC, and Lucent - LC fiber connectors, their application, performance, and their termination requirements. In the last issue of Technically Speaking, I presented the basic characteristics and considerations for the fiber conductor. Which equipment transmission format should be used: analog or digital? Is digital transmission hardware available? Does this application require multimode or singlemode fiber? How do I deal with the customer's existing installed fiber? What fiber connectors do I use? Figure 1: ST style connectors - booted black tip pictured above and unbooted below. The fiber transmission solution is still a serious investment consideration requiring careful planning and implementation. A fiber solution may sound like a great idea for those challenging long-haul or highly secure applications, and then reality sets in. Optical fiber transmission of AV signals has come of age and it's time to take another step along this new, adventurous road. By Steve Somers, Vice President of Engineering