Abstract

Molded biconic connectors are successfully being used in large quantities in the Bell System's multimode lightwave systems, with losses of the order of 0.5 dB routinely being achieved.¹ To obtain a similar performance with single-mode fibers, approximately an order of magnitude improved alignment tolerances are required. Typically single-mode fibers operating in the 1.3-μm wavelength region have core diameters between 8 and 10 μm. Therefore, to achieve losses of the order of 0.5 dB, the fiber cores have to be aligned to within 1.5 μm, and with an angular offset below 1°. As previously reported, this type of precision can be achieved with a taper-trimming technique, and losses of 0.28 dB (average) could readily be achieved with standard-toleranced fibers.² While this technique requires termination of the fibers before trimming, we describe in the following a field-installable connector plug that when used with existing multimode hardware, a more tightly toleranced biconic alignment sleeve that is selected from standard multimode sleeve fabrication, and precisely concentric fibers, also results in the required precision alignment and correspondingly low insertion losses (Fig. 1).

© 1983 Optical Society of America