Markus Giebel - Shrinking fiber-optic connectors

The incredible shrinking fiber-optic connectors

This is an extract from - CablingInstall.com

"The duplex SC is basically two single-fiber SC connectors clipped together," explains Siecor product manager Markus Giebel. "The scdc uses the same footprint and housing as a single-fiber SC connector, yet still terminates two fibers, both in one ferrule, instead of one in each of two ferrules. This basically doubles--or quadruples in the case of the scqc--the density as compared to the duplex SC."




Since the 2-fiber scdc and 4-fiber scqc are housed in the same footprint as the single-fiber SC, "the installation practices and tools as well as the hardware that supports the SC connectors will support the scdc/scqc," notes Giebel. In addition, transceiver manufacturers are able to incorporate these connectors into their components because of the SC-like technology. And just like the SC, the scdc and scqc connectors are symmetrical--connectors can be mated to each other, unlike a plug-and-socket design.

 "In other words," Giebel explains, "any scdc can mate to another scdc connector with a simple adapter, just like the SC connectors. There are no separate plug-and-socket designs or guide pins, and an scdc can be terminated in the field as a jumper or a pigtail or installed in the backplane of a wallplate. There are no proprietary or sole-source fibers, jumpers, or components required to install a network using an scdc/scqc." Congdon says that these characteristics mean less inventory, better economies of scale, and fewer related problems.

The scdc/scqc footprint is similar to the RJ-45`s, but, Congdon qualifies, "there is no external latching mechanism since it is not needed to engage the connection: The internal design used in all SC connectors provides the latch. The scdc and scqc designs use the simple push-pull arrangements common to most optical-fiber connectors. To disconnect, the housing is pulled from the adapter, which is advantageous for high-density applications, where an external latching mechanism can complicate moves, adds, and changes."

The scdc and scqc accept single fibers--either 900- micron buffered fibers or 250-micron fibers--as well as 2- or 4-fiber ribbon. They incorporate two new internal features: an offset keyway to prevent mating a single-fiber SC with a multiple-fiber SC and alignment grooves to maintain the fiber plane alignment of the mated connectors. Testing shows that the scdc/scqc connectors meet the optical, mechanical, and environmental performance requirements of tia/eia-568a for multimode and singlemode fibers, according to Giebel.

The connectors are available in a connectorized cable assembly and as a field-installable version. "For large volumes of connectors," notes Giebel, "it might be advantageous to purchase bag-of-parts products and install these using the standard epoxy and polish methods. Time savings are realized, because two fibers--or four for the scqc--are polished simultaneously as compared to polishing two or four separate SC connectors." The 2-fiber field-installable versions, when coupled with mechanical-splice and factory-polished fiber stub technologies, he says, can be terminated in the field in less than one minute.