The present invention relates generally to receptacles for fiber optic ferrules, and more particularly, the present invention provides a receptacle having improved alignment and mounting capabilities for a fiber optic ferrule.
Referring to FIG. 1, illustrated is a sectional view of an optical module 10 configured in accordance with the prior art. The optical module 10 includes a housing 12 having a cylindrical sleeve 11 with a bore 14. The housing 12 is constructed of metallic material that can be welded or bonded to a semiconductor element 16. The semiconductor element 16 has an annular flange 18 and electrical leads 20 extending from a base 22. The semiconductor element 16 is mounted within a socket 24 of the optical module 10. The semiconductor element 16 is positioned against the inner walls 26 of the socket by spacers 28. The semiconductor element 16 is secured within the socket 24 by welding or using an adhesive.
The semiconductor element 16 shown in the illustrated embodiment includes a light emitting diode (LED) 30. In other embodiments the LED 30 can be replaced by a semiconductor laser as a light source. Light waves emitted from the LED 30 are communicated via an optical fiber 32. An optical ferrule 34 houses and mounts the optical fiber 32 within the bore 14. An optical fiber terminal 36 positions and mounts the optical fiber cable 38 within the optical ferrule 34.
The diameter of the bore 14 within the cylindrical sleeve 11 is constant. The optical ferrule 34 is inserted and held within the bore 14 resulting in a tight fit within the bore 14. As a result of the tight fit between the optical ferrule 34 and the bore 14, misalignment or physical damage to the optical ferrule 34 and/or the bore 14 sometimes results.
Semiconductor optical transmitters typically have the design as illustrated in FIG. 1. Performance of an optical semiconductor transmitter is affected by improper alignment of the transmitter lens or LED 30 with then input end 31 of the optical fiber 32. Proper alignment maximizes the amount of light from the LED 30 to be focused on the input end 31 of the optical fiber 32. Conventional techniques for improving this alignment include minimizing the space or gap between the optical ferrule 34 and the bore 14 when the optical ferrule 34 is inserted into the bore 14.
A single-mode optical fiber has a diameter of approximately 10 microns, and the diameter of the bore 14 should match the ferrule 34 diameter on the order of less than several microns in terms of both the tolerance of diameter and circularity. Numerous steps are used in the fabrication process in order to achieve such a high degree of accuracy. Since a conventional housing 12 is made out of metal, very refined mechanical processing is required to fabricate the housing 14. Moreover, since the diameter of the optical ferrule 34 is typically 2.5 mm, surface roughness must be minimized in order reduce friction and allow insertion or removal of the optical ferrule into or out of the bore in the sleeve.
Accordingly, there is a need for an optical ferrule receptacle providing improved alignment of an optical ferrule, which can be produced at an attractive cost.
An object of the present invention is to provide a receptacle for an optical ferrule having improved alignment capability.
Another object of the present invention is to provide an optical ferrule receptacle that can be produced at a reduced cost.
A further object of the invention is to provide an optical ferrule receptacle constructed out of a single-molded material, such plastic or other polymer.
An additional object of the invention is provide an optical ferrule receptacle having improved socket mounting capabilities for receiving an optical transmitting source.
Another object of the invention is to provide an optical ferrule receptacle having improved capabilities for mounting optical ferrules by minimizing damage to the optical ferrule and optical fibers during the insertion process.
A further object of the invention is to provide an optical ferrule receptacle having increased assembly speed by facilitating the insertion and securing of the optical ferrule within a an optical bore of the optical ferrule receptacle.
Moreover, an object of the present invention is to provide a notch in the housing for a gate where molding material is injected, thereby eliminating the need to remove surrounding excess molding material. The gates are also located in the rear of the receptacle to allow axial flow of molding material during injection molding, thereby producing a symmetric flow around core pins which increases the accuracy of ferrule bore dimensions.
According to the present invention, a fiber optic ferrule receptacle is provided having a single-molded housing having a base, a cylinder on a first side of the base having a bore for receiving an optical ferrule, a socket on a second side of the base opposite the first side, for receiving a ball lens, and the bore having a first diameter at an outer opening distal to the base, and a second diameter at an inner opening adjacent to the base, wherein the first diameter is greater than the second diameter. In a second embodiment of the present invention, a single-molded housing is provided having a base, a cylinder on a first side of the base having a bore for receiving an optic ferrule, a socket on a second side of the base, opposing the first side, for receiving an optical element; and a plurality of sloping ridges located on the inner wall of the cylinder, wherein widths of the sloping ridges increase closer to the base.
FIG. 1 is a sectional view of an optical ferrule receptacle configured in accordance with the prior art;
FIG. 2 is a perspective view of an optical ferrule receptacle and an adjoining cylinder configured in accordance with the present invention;
FIG. 3 is a side view of the optical ferrule receptacle and cylinder shown in FIG. 2, wherein the internal configurations are shown in shadow;
FIG. 4 is an enlarged side view of the optical ferrule receptacle and cylinder shown in FIG. 3, wherein the optical ferrule receptacle and cylinder are coupled together;
FIG. 5 is a perspective view of an optical ferrule receptacle configured in accordance with a second embodiment of the present invention;
FIG. 6 is a cross-sectional view of the optical ferrule receptacle shown in and taken along line 6xe2x80x946 of FIG. 5;
FIG. 7 is an end view of the optical ferrule receptacle shown in and taken along line 7xe2x80x947 of FIG. 6; and
FIG. 8 is a perspective view of the optical ferrule receptacle shown in FIG. 5, wherein the internal configuration is shown in shadow.
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