High optical fiber count connector

#The invention relates generally to connectors and, in particular, to a high optical fiber count connector.

#Fiber optic connectors are used to terminate optical fiber cables and to facilitate connection of the cables to other cables or other optic fiber transmission devices. A typical fiber optic connector includes a ferrule which mounts and centers an optical fiber or fibers within the connector. The ferrule may be fabricated, for example, from ceramic or plastic material. A ferrule holder or body member of the connector embraces the ferrule and may be fabricated of such material as molded plastic or aluminum. A spring may be disposed within the body member such that the ferrule is yieldably biased forwardly for engaging another fiber-mounting ferrule of a mating connecting device.

#Connectors of the type described above are designed to terminate a relatively small number of optical fibers. For example, the so-called MPO/MTP® connector was designed to terminate up to 24 optical fibers. In practice, however, higher fiber counts are achievable using shrink tubing and other similar methods to transition larger cables into the connector. However, this does not always lead to satisfactory results. For example, current latch designs on MPO/MTP® connectors cannot withstand the required operating temperatures or pull test requirements associated with higher fiber count cables. As such, failure of the connector and/or fiber cables is more likely to occur.

#The invention will be more readily understood in view of the following description when accompanied by the below figures and wherein like reference numerals represent like elements:

#FIG. 1 is an exploded, perspective view of a first connector assembly in accordance with a first embodiment of the present invention;

#FIG. 2 is an enlarged, cross-sectional view of the first connector assembly of FIG. 1 taken along line 2-2;

#A first connector assembly 100 in accordance with a first embodiment of the present invention is described in greater detail with reference to FIGS. 1 and 2. A circular body member 101 having a front opening 102 receives a ferrule 104 that terminates a plurality of optical fibers 106. Preferably, the body member 101 is fabricated from aluminum or other suitably strong material. Additionally, although a circular body is illustrated, this is not a requirement and body members having other configurations may be equally employed. As shown, the optical fibers 106 may be configured in a ribbon arrangement, although other arrangements may be equally employed. The ferrule 104 is fabricated from materials well known to those having skill in the art. As better illustrated in FIG. 2, flanges 206 are provided within the body member 101 and are configured to receive the ferrule 104 and maintain it in a fixed position relative to a longitudinal axis 190 of the body member 101. In this manner, the ferrule 104 is substantially prevented from moving in a radial direction relative to the longitudinal axis 190 but is allowed to move axially along the axis 190. In a preferred embodiment, the body member 101 is configured such that the front opening 102 is sufficiently distal from a front surface 105 of the ferrule 104 such that the chances of misaligning a mating connector, and thereby damaging the front surface 105, are substantially minimized.

#As known in the art, guide pins may be used to very precisely align mating ferrules to thereby ensure high quality optical connections between optical fibers. To this end, a guide pin holder is provided comprising at least two open members 108 each having at least one guide pin 110 disposed substantially perpendicular to a forward surface 109 of each open member 108 and substantially parallel to the longitudinal access 190. The open members 108 may be fabricated from plastic or other suitable material. Likewise, the guide pins are preferably made of stainless steel. Additionally, in a preferred embodiment, openings 107 are provided in the ferrule 104 extending from the front surface 105 to a back surface of the ferrule 104, and configured to receive the guide pins 110 thereby positioning the open members 108 in a fixed position around the plurality of fiber optic fibers 106. Each open member 108 additionally comprises a rearwards-facing biasing surface 112 that is configured to receive one end of a low profile resilient member 114. Advantageously, the guide pin holder in accordance with the present invention may be mated to the ferrule 104 subsequent to polishing of the front face 105, thereby simplifying the assembly process.

#When positioned within the connector assembly 100, the low profile resilient member 114 provides a biasing force to the ferrule 104 in a direction of the front opening 102. As a general guide, it is desirable to select the resilient member 114 such that a force of approximately 10 N is provided for every twelve optical fibers terminated within the connector assembly 100, although it may be preferable not to exceed an upper threshold, e.g., 30 N, to account for the possibility of placing an undue amount of force on a single fiber longer than the others. The low profile resilient member 114 is also configured to provide a reduced linear (axial) dimension when maintained in a compressed state. In prior art systems, resilient members used to bias the ferrule in a forward direction typically comprise a coil spring fabricated from wire having a substantially circular cross section. Notably, each coil in such springs has the same radius about a longitudinal axis of the spring. As a result, when such coils are compressed, thereby causing the coils to abut one another, the lowest axial dimension of the spring is limited by the number of coils in the spring and the cross-sectional diameter of the wire. As a consequence, the overall length of the resulting connector tended to be rather large to account for the axial dimension of the resilient member. In contrast, the low profile resilient member 114 is configured such that is provides a substantially reduced linear dimension when maintained in a compressed state. For example, the resilient member 114 illustrated in FIG. 1 comprises a so called wave spring fabricated from steel wire having a flat, rectangular cross section, such as those manufactured by the Smalley Steel Ring Company of Lake Zurich, Ill. In an alternative embodiment, the low profile resilient member 114 may instead comprise a conical spring. A conical spring includes a series of coils of increasingly smaller radial diameter such that, when the conical spring is compressed, the coils nest within each other thereby providing an axial dimension substantially equal to the wire diameter of a single winding.