Novel small form factor optical ribbon fiber connector for singlemode applications

We present the concept of a new type of small form factor singlemode ribbon connection for up to 12 optical fibers which achieves a mean insertion loss below 0.2 dB and a return loss above 60 dB. The system consists of two connectors, which terminate the ribbon cable ends and an adapter, which hosts an alignment element. In contrast to MT-ferrule based connectors, the fibers are neither fully fixed inside a ferrule, nor mechanically polished. Within the connector, the ribbon ends are decoated over a length of few millimeters and attached to a ceramic carrier. The fibers are glued to the carrier at the transition between the coated and decoated zone while the tips are aligned to the front edge of the carrier. In the intermediate region, which is used for the alignment, the uncoated fibers are lying unconfined on the flat carrier surface. The adapter consists of contours, which guide and pre-align the fiber carriers upon insertion of the connectors. A controlled movement assures that the fibers are sliding smoothly into v-groove alignment structures which are part of the adapter. When both connectors are fully inserted, the fiber pairs are in physical contact under a defined pressure. Since each individual mating fiber pair is centered within a common v-groove, a mean insertion loss below 0.2 dB with maximum loss values below 0.4 dB for singlemode connections has been achieved. The lateral flexibility of uncoated part of the fibers allows for a compensation of positioning errors in the order of /spl plusmn/20 /spl mu/m. Flatness tolerances of the bearing surface are compensated by use of a thin flexible membrane, which guarantees the perfect fit of the fibers in the v-grooves. For optimum mating contact and high return loss, an endface flatness in the core area below 50 nm and a length uniformity of the fibers of /spl plusmn/2/spl mu/m is required. These goals are met by employing a high precision laser cleaving process. We report measured return loss values in the order of 70 dB, The presented prototype serves as the base for the development of Huber+Suhner's new singlemode and multimode ribbon connector called FiberBus.