CN111758058A

CN111758058A - Optical fiber connection system

Info

Publication number: CN111758058A
Application number: CN201980013982.9A
Authority: CN
Inventors: 纳撒尼尔·S·肖克维拉; 威廉·J·克拉塔诺夫; 理查德·L·西蒙斯; 唐纳德·K·拉森; 丹尼尔·J·崔德威尔; 拉斯洛·马科斯
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2018-03-07
Filing date: 2019-02-26
Publication date: 2020-10-09
Also published as: WO2019171209A1

Abstract

Described herein are fiber optic connection systems configured to interconnect a first optical fiber and a second optical fiber.

Description

Optical fiber connection system

Technical Field

The present invention relates to a ferrule-less fiber optic connection system for interconnecting a plurality of first optical fibers and a plurality of second optical fibers, the ferrule-less fiber optic connection system comprising a fiber optic plug and a receptacle.

Background

Communication network owners and operators face an increasing demand to deliver faster and better services to their customers. They can meet these demands for greater bandwidth by incorporating optical fibers into their networks. Fiber optic cables are used in optical networks to transmit signals between access nodes to transmit voice, video, and data information.

Some conventional fiber optic cables include fiber optic ribbons that include coated optical fiber groups arranged in a planar array. The optical fibers in the ribbon are disposed substantially parallel to each other. Optical fiber ribbons are typically interconnected using multi-fiber optical connectors, such as MPO/MTP connectors, which may be used in data centers or other points in a network where parallel optical interconnections are desired.

Data centers rely on 20G and 40G transmission rates, which are relatively mature technologies. As the way people use the internet has changed, global data center Internet Protocol (IP) traffic is expected to increase by about 31% per year over the next five years. Cloud computing, mobile devices, globally accessible video and social media content are driving data centers to migrate from 20G and 40G transfer rates to 200G and 400G transfer rates.

Data centers are moving towards 40G/100G transmission rates that utilize multiple parallel network links, which are then aggregated to achieve higher overall data rates. The polarity in the fiber routing is essentially the matching of the transmit signal (Tx) and the receive equipment (Rx) at both ends of the fiber link by providing transmission over the entire fiber system to the receive connection. The polarity is managed by using transmit and receive pairs (duplex wiring), but becomes more complex for multi-fiber connections that support multiple duplex pairs, such as MPO/MTP connectors.

Higher bandwidth links will require more power to ensure signal transmission integrity. Heat dissipation of electronic devices has become a concern today, and further increases in power will exacerbate the problems that data centers have faced. This increasing demand for more power and the desire to install future flexible structured cabling systems is pushing interconnect performance towards low loss performance (less than 0.1dB per connection point).

Conventional single fiber ferrule type connectors are easy to reconfigure, but suffer from high optical loss (0.2dB-0.3dB) and even higher loss (0.35dB-0.7dB) for multi-fiber ferrule type connectors such as MPO/MTO connectors. Ferrule type connectors must be cleaned each time they are mated. Furthermore, the space required for the ferrule-type connector limits the interconnection density.

Fusion splicing is another conventional interconnection method that produces a low-loss, durable, reliable splice. However, handling 250 micron fibers during preparation, fusion and storage can be cumbersome. Today, such fusion splices typically require their own splice trays in data centers.

Finally, conventional gel-type mechanical splices provide a durable and reliable fiber splice with insertion losses that are better than connectors and approach that of fusion splices. However, these mechanical splices employ index-matching gels that are not solid materials and therefore do not provide structural integrity.

Therefore, new multi-fiber interconnect technologies that provide "fusion-like" optical performance are needed to facilitate migration of data center bandwidth from today's 20G and 40G transmission rates to future 200G and 400G transmission rates.

Disclosure of Invention

In accordance with an embodiment of the present invention, a ferrule-less fiber optic connection system configured to interconnect a plurality of first optical fibers and a plurality of second optical fibers is described herein. The connection system includes: a receptacle comprising a first splice member configured to hold and align a plurality of first fibers of a first fiber array, and a receptacle housing having an internal passage for holding the first splice member; and a plug including a second splice member for holding at least a plurality of second fibers of the second fiber array, and a plug housing for holding the second splice member. An optical connection is made between a first optical fiber in the first optical fiber array and a second optical fiber in the second optical fiber array by inserting the plug into the internal passageway of the receptacle. In an exemplary aspect, the first splice member and the second splice member each include a splice body having a plurality of alignment channels formed in a top surface of the splice body to guide, align, and/or hold optical fibers from the first optical fiber array and the second optical fiber array, respectively.

In another embodiment, a ferrule-less fiber optic connection system includes: a receptacle comprising a first splice member configured to hold a plurality of first fibers of a first fiber array, and a receptacle housing having an internal passage for holding the first splice member; and a plug including a second splice member for holding and aligning at least a plurality of second optical fibers of the second optical fiber array, and a plug housing for holding the second splice member. An optical connection is made between a first optical fiber in the first optical fiber array and a second optical fiber in the second optical fiber array by inserting the plug into the internal passageway of the receptacle. In an exemplary aspect, the first splice member and the second splice member each include a splice body having a plurality of alignment channels formed in a top surface of the splice body to guide, align, and/or hold optical fibers from the first optical fiber array and the second optical fiber array, respectively.

The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The figures and the detailed description that follow more particularly exemplify these embodiments.

Drawings

The invention will be further described with reference to the accompanying drawings, in which:

fig. 1A and 1B are two views of a fiber optic connection system according to aspects of the present invention.

Fig. 2A-2D are four views of an exemplary receptacle according to aspects of the present invention.

Fig. 3A-3B are two views of an exemplary splice element that may be used in the receptacle of fig. 2A-2D.

Fig. 4 is a schematic diagram showing a plurality of optical fibers being held between two mating splice elements of the embodiment shown in fig. 3A-4B.

Fig. 5A and 5B are two views of an element holder according to aspects of the present invention.

Fig. 6A-6E are five views of a first embodiment of a plug according to aspects of the present invention.

Fig. 7A-7D are four cross-sectional views illustrating mating of a plug and a receptacle forming a fiber optic connection system according to aspects of the present invention.

Fig. 8A-8C are three views of an alternative fiber optic connection system according to aspects of the present invention.

Fig. 9A-9D are exemplary receptacle views of alternative exemplary receptacles according to aspects of the present invention.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.

Detailed Description

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as "top," "bottom," "front," "rear," "forward," and "aft," etc., is used with reference to the orientation of the figure or figures being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention.

Optical communication systems are using more and more optical fiber cables. Glass fibers transmit data-carrying light over a network. Ideally, the incident light intensity injected into the optical fiber would be extracted from the optical fiber at the opposite end of the communication line. However, optical power may be lost along the transmission line. One possible source of signal loss is when a fiber optic cable has been cut, broken, or otherwise needs to be connected to another optical fiber. Because optical fibers rely on total internal reflection of signals in the core of the optical fiber, alignment of the fiber core is necessary to minimize optical loss through the connection.

Common methods of aligning optical fibers include ferrule-based alignment systems in which the optical fiber is disposed within a precision component or ferrule that can then be mated together within a precision alignment sleeve. The one or more precision holes are typically formed by drilling, extruding or molding through the center of the ferrule. The optical fiber is secured within the precision hole by an adhesive and the terminal end of the optical fiber is polished. Typically, ceramic or metal ferrules are used in fiber optic connectors in which a precision center hole is drilled. Precision ferrules are a significant contributor to the manufacturing cost of fiber optic connectors.

Non-ferrule or ferrule-less connection systems do not utilize the precision ferrules of ferrule-type connectors. The precision v-groove is a ferrule-less means of aligning the optical fibers.

The exemplary fiber optic connection systems described herein include a plug and a receptacle in which the same splice element is disposed. The splice elements are identically terminated and then assembled into receptacle and plug or bare fiber holder hardware that facilitates mating of two fiber arrays in an end-to-end manner. When mated, the unique design and termination process of the splice element enables fibers in the first array of fibers to be mated with corresponding fibers in the second array of fibers (i.e., a first fiber in the first array will mate with a first fiber in the second array of fibers until the nth fiber in the first array mates with the nth fiber in the second array of fibers). The receptacle and plug of the exemplary fiber optic connection system may be polarity independent, thereby alleviating network design, installation, and maintenance issues by managing the polarity of the connected communication links.

Fig. 1A and 1B illustrate a fiber optic connection system 100 that provides a ferrule-less interconnection system for optically coupling a plurality of first optical fibers and a plurality of second optical fibers. The fiber optic connection system 100 includes a receptacle 120 and a plug 220 that are each mounted on a terminal end of a fiber optic cable. The plug and receptacle mate together to make an optical connection between an optical fiber of the receptacle's fiber optic cable and an optical fiber in the plug's fiber optic cable. Fig. 1A shows the plug and receptacle in an unmated state, while fig. 1B shows the plug and receptacle in a mated state.

The receptacle comprises a receptacle housing 121 having a generally tubular forward end 120a including a passageway 122 disposed therein. The passageway is sized to allow insertion of the plug 220 such that a majority of the plug 220 is disposed within the receptacle when the optical connection is made. The plug and receptacle may be secured in a mated state by a mechanical latch or fastener, or may be permanently attached to each other with an adhesive.

Each of the plug 220 and the receptacle 120 manages and protects a fiber optic array of one or more optical fibers having an exposed glass portion adjacent an end face or terminal end of the one or more optical fibers. In other words, the polymer coating has been removed from at least a portion of the circumferential diameter of the one or more optical fibers to facilitate alignment during mating of the exemplary plug and receptacle to optically interconnect the array of optical fibers held by the plug and receptacle.

In an exemplary aspect, the fiber optic connection system 100 includes a plug 220 and a receptacle 120 that may be field terminated or installed in the field onto a fiber optic cable or ribbon and then assembled to form a semi-permanent or permanent optical connection. Alternatively, the plug 220 and receptacle 120 may each be factory terminated, installed or mounted onto a fiber optic cable or ribbon and assembled together in the field for optical connection.

As shown, the fiber optic connection system 100 is configured as a multi-fiber optical splice connection system. In the exemplary embodiments described herein, the fiber optic connection system is configured to connect a first fiber array and a second fiber array. In the exemplary embodiments provided herein, the fiber optic connection system is configured to connect two 12-fiber arrays. As will be apparent to those of ordinary skill in the art given the present description, the fiber optic connection system 100 can be modified to include fewer fibers or a greater number of fibers in each fiber array. In one exemplary aspect, the fiber optic connection system 100 may be modified as a single fiber splice connection system.

Fig. 2A-2D illustrate features and components of the receptacle 120. Receptacle 120 includes a receptacle housing 121 having a first or lower housing portion 130 and a second or upper housing portion 140 securable together to form a receptacle housing, a splice element 160, and a cradle or element holder 170 disposed in the receptacle housing. The receptacle housing 121 is configured to arrange and retain the remaining components of the receptacle and protect the exposed bare glass portions 55 of the optical fibers 54 supported within the receptacle. A crimp ring (not shown) may secure the first and second housing portions together. Optionally, latching features (not shown) may be added to further secure the first and second housings. Alternatively, the first and second housing portions may be adhesively bonded together, secured by a snap fit or other latching system. In an alternative embodiment, the socket housing may have a clamshell configuration with a first housing portion and a second housing portion joined by a living hinge. In the exemplary embodiment shown in fig. 2A through 2D, each of the first and

second housings

130, 140 may include a

semi-cylindrical anchor portion

133, 143 formed at their second or

rear ends

130b, 140b, respectively. When the first and second housing parts are assembled to form the receptacle housing 121, the

semi-cylindrical anchor parts

133, 143 form a cylindrical anchor part 123. A crimp ring may be fitted over and secured to the cylindrical anchor portion 123 to anchor the cable jacket or strength members of the fiber optic cable to the receptacle to enhance cable retention strength in the receptacle. In the exemplary aspect shown in the figures, the cylindrical anchor portion has a smooth outer surface. In some embodiments, it may be desirable to add teeth or ribs to the outer surface of the cylindrical anchoring portion to further enhance retention. Optionally, a strain relief boot 110 may be installed over the crimp ring to provide strain relief and bend control for the optical fiber or fiber optic cable 50 at the point where the optical fiber enters the receptacle housing.

In an exemplary aspect, the first and

second housing portions

130, 140 can have a generally open rectangular channel profile with a

base

132a, 142a and a pair of

parallel walls

132b, 142b extending from the base, a side wall with a

top edge

132c, 142c extending along a length of the side wall. When the first and second housing portions are assembled into the receptacle housing 121 and the passage 122 into which a mating plug is to be inserted is created, the top edge 132c of the first housing portion 130 is joined to a portion of the top edge 142c of the second housing portion 140.

Each of the

housing portions

130, 140 may include an

optional flange portion

136, 146 extending substantially perpendicularly from an outer surface of the housing portion. When the first housing portion 130 and the second housing portion 140 are assembled together, the flange portions will create the mounting flange 126. The mounting flanges 126 may be used to secure the receptacle 120 into a panel or bulkhead in a patch panel or module (not shown) using mechanical fasteners placed through the mounting holes 127 in the mounting flanges 126. Although each of the housing portions in the present embodiment includes a flange portion, the entire mounting flange may be integrally formed with one of the housing portions. The flange portion may be disposed at any point along the outer surface of the housing portion as desired for a particular application.

Referring to fig. 2B and 2D, a leaf spring 180 may be attached to the first housing portion 140 of the receptacle 120 to provide a vertical mating force (represented by directional arrow 92 in fig. 7D) on the bottom surface 272D of the element holder 270 of the mating plug 220. In an exemplary aspect, the first housing portion 130 includes a pair of spaced apart anchor rods 137 formed on the inner surface 131 of the second housing portion. The leaf spring 180 may fit into a slot 138 (fig. 2D) formed in the anchor bar to secure the leaf spring to the first housing portion. The leaf spring may have a generally arcuate profile comprising two arcuate arms 182 connected at both ends by a flat foot portion 184. The foot portion fits into a slot formed in the anchor bar to secure the leaf spring to the second housing portion. In an exemplary aspect, the leaf spring may be stamped and formed from a sheet of spring steel as the leaf spring shown in fig. 2B.

Receptacle 120 also includes a fiber alignment mechanism or splice element 160 held by an element holder 170. The splice element 160 is configured to join a plurality of parallel optical fibers 54 when mated with another splice element 260 disposed in a mating plug 220, as described below. The

splice members

160, 260 are structurally equivalent.

Referring to fig. 3A-3B, splice member 160 has a generally rectangular body 161. In an exemplary aspect, the body 161 is shaped as a rectangular frustum. In alternative aspects, the body may have another shape, such as a trapezoidal prism, a semi-cylindrical solid, a birefringent prism, or other three-dimensional shape having at least one substantially flat major surface. The body 161 has a bottom surface 161a, a smaller top surface 161b, and four sloped sidewalls 161c-161f extending from the bottom surface to the top surface. In an exemplary aspect, the sidewall is inclined at an angle between 45 ° and about 85 ° with respect to the bottom surface (preferably at an angle of about 60 °).

The splice member 160 has an integral alignment and clamping mechanism for one or more optical fibers in the form of a plurality of alignment channels 165 formed in the top surface 161b of the body 161 between first and second

fiber landing areas

167a, 167b disposed adjacent the first and

second ends

161a, 161b, respectively, of the splice body. Each alignment channel is configured to guide and support a single optical fiber. In the exemplary embodiment shown in fig. 3A, the splice element has 12 parallel alignment channels. In alternative embodiments, exemplary fiber optic splicing elements can have fewer or more alignment channels depending on the end application and the number of optical fibers to be spliced. Thus, in some embodiments, the splice element can have a single alignment channel for joining a pair of simplex fiber optic cables. In other embodiments, an exemplary splice element may have a greater number of alignment channels.

When alignment channel 165 extends from first fiber landing zone 167a and second fiber landing zone 167b of splice element 160, the alignment channel can be substantially flat or planar. In the exemplary embodiment shown in fig. 3A-3B, the alignment channel is a continuous structure that extends from a first inlet opening 163A near a first end 161a of the splice body 161 to a second inlet opening 163B near a second end 161B of the splice body 161. The alignment channel may have a characteristic cross-section, such as a trapezoidal profile as shown in FIG. 4. Alternatively, the alignment channel may have a semi-circular cross-section, a rectangular cross-section, a v-shaped cross-section.

The optical fiber may be inserted into the alignment mechanism through the

entrance openings

163a and 163 b. In some aspects, the

inlet openings

163a, 163b may include funnel-shaped inlet portions formed by the tapering of the partitions 164 between adjacent channels to provide more direct fiber insertion. In other embodiments, the entrance aperture may be fully or partially tapered or funnel-shaped to guide the insertion of the optical fiber into the alignment channel 165.

The alignment channel may have a comb-like structure 169 adjacent to at least one of the first and second entrance openings to facilitate insertion of the optical fibers into the alignment channel 165. In a comb-like structure, a portion 164a of the divider or wall 164 between adjacent aligned channels is taller and tapered than the remaining section 164b of the divider 164.

The

inlet openings

163a, 163b are characterized by the pitch between the channels (i.e., the distance between the centerlines of adjacent aligned channels). In the embodiment shown in fig. 1A and 1B, the channel pitch at the first end of the splice member is the same as the channel pitch at the second end of the splice member. In this exemplary embodiment, the pitch between the channels is about the same as the spacing between the optical fibers in a conventional 12-fiber ribbon. In alternative embodiments, the inter-channel pitch at the first end of the splice element and the channel pitch at the second end of the splice element can be different. For example, the channel pitch at the first end of the splice element can be set to the fiber spacing of a conventional fiber optic ribbon, while the channel pitch at the second end of the splice element can be a different value, such as when splicing a single fiber or when splicing two or more smaller fiber optic ribbons or fiber optic modules to a larger ribbon fiber.

The alignment channel 165 is configured such that an optical fiber disposed in the alignment channel will contact each of the

angled channel walls

165a, 165b of the alignment channel along

contact lines

54a, 54b that disappear into the page in fig. 4 along the length of the optical fiber disposed within the alignment channel. Thus, when the two

splice elements

160, 260 are brought together, each fiber will have four

contact lines

54a, 54b, 54a ', 54 b' with the splice elements to reliably position and hold the fibers. In an exemplary aspect, the four contact lines may be relatively evenly spaced around the optical fiber.

In the embodiment shown in fig. 4, the inclined channel wall of the alignment channel may be disposed at an angle of between 38 ° and about 60 ° with respect to the bottom wall 165c of the alignment channel, preferably at an angle of about 45 ° with respect to the bottom surface. The alignment channel may be characterized by a characteristic alignment channel width between contact lines extending longitudinally along the angled channel walls of the alignment channel, where the optical fiber contacts the alignment channel. In exemplary aspects, the alignment channel width can be between about 85 microns and about 120 microns, preferably between about 95 microns and about 110 microns.

The optical fibers may be secured directly to the splice element 160 using an adhesive. For example, an adhesive such as a fast curing UV or visible light initiated adhesive or a heat activated adhesive or a hot melt material may be utilized to secure the optical fiber array within the comb structure 169 and/or the land area 161a of the splice element. Securing the fiber in this region of the splice element provides the advantage of remotely gripping the fiber.

The splice element body can be formed of a silica material, particularly a net shape cast and cured silica material, as described, for example, in U.S. provisional patent applications 62/382944 and 62/394547, each of which is incorporated herein in its entirety. In an exemplary embodiment, the splice element made of net shape cast and cured silica material is transparent. For example, a net shape cast and cured silica material may have a transparency of greater than about 90% at light wavelengths of 430nm to about 480 nm. Such transparent net shape cast and cured silica materials allow the use of a visible light source directed from the exterior of the structure through the splice element to cure the optical adhesive disposed therein. By utilizing a net shape cast and cured silica alignment mechanism and an adhesive composition comprising silica nanoparticles, the temperature performance of the splice member can be stable over a wide temperature range because the thermal characteristics of the optical fiber and the splice member are substantially the same.

The component holder 170 includes a collar portion 171 that is attached to a component table 172. In some embodiments, the collar portion 171 may have a generally cylindrical shape configured to receive a portion of a compression spring. As shown in fig. 5A, the collar portion may have an opening 171b through an end wall portion 171d where the component table is attached to the collar portion. The opening allows the optical fiber to pass through the end wall of the grommet-part element holder.

The component table 172 has a base and a sidewall 172b extending from the base. The sidewall extends from the second end 170b of the element holder to the collar portion 171 along a longitudinal edge of the base. The base has a top surface 172a and a bottom surface 172 d. Splice member 160 is anchored to the top surface by

member fasteners

173, 174. In an exemplary aspect, the side walls may include a protrusion or tab 172c formed on the top of the side wall 172b to control the vertical offset between the splice elements held on the element holder during mating of the plug 220 with the receptacle 120.

In an exemplary aspect, the component table 172 can include a window 175 extending through a base of the component table below an interconnection region on the splice component 160 with the first and second optical fibers joined end-to-end. In an exemplary aspect, a pair of receptacles 120 may be permanently joined together by an index-matching optical adhesive. Exemplary optical adhesives may be cured by actinic radiation via a rapid and straightforward process using an eye-safe visible, e.g., blue, LED light source such as that described in U.S. patent application 15/695842, which is incorporated herein by reference in its entirety. Curing radiation may be projected onto the adhesive through the window 175 through at least one of the exemplary splice elements.

The gasket portion 171 may also include detents (pall)171c extending from an outer surface 171a of the gasket portion of either side of the gasket portion. A translational gap 179 is formed between the pawl and the end 172c of the side wall 172 b. When two of the example receptacles 120 are mated together, the tapered

ridges

139, 149 provided on the inner surfaces of the first and

second housing portions

130, 140 form a track that fits in the translation gap 179 to control the relative vertical position of the element holder 170.

In some embodiments, one or both of the

housing portions

130, 140 may include a window extending through the

base portions

132a, 142a of the housing portions proximate to an interconnection region where the terminal ends of the optical fibers meet to enable curing of the optical adhesive in the interconnection region.

Fig. 6A-6E illustrate features and components of the plug 220. The plug 220 has a first housing portion 230 and a second housing portion 240 that may be secured together to form a plug housing 221. The plug housing 221 is configured to arrange and retain the remaining components of the plug and to protect the exposed bare glass portion 55 of the optical fiber 54 supported within the plug. The crimp ring 250 may secure the first and second housing portions together. Optionally, additional latching features (not shown) may be added to further secure the first and second housings. Alternatively, the first and second housing portions may be adhesively bonded together, secured by a snap-fit or latching system. In an alternative embodiment, the plug housing may have a clamshell configuration with a first housing portion and a second housing portion joined by a living hinge.

Each of the first and

second housings

230, 240 may include a

semi-cylindrical anchor portion

233, 243 formed at their

second ends

230b, 240b, respectively. The

semi-cylindrical anchor portions

233, 243 form a cylindrical anchor portion 223 when the first and second housing portions are assembled into the plug housing 221. A crimp ring 250 may be fitted over and secured to the cylindrical anchor portion 223 to anchor the cable jacket or strength members of the fiber optic cable to the plug to enhance cable retention strength in the plug. In the exemplary aspect shown in fig. 6A, the cylindrical anchor portion has a smooth outer surface. In some embodiments, it may be desirable to add teeth or ribs to the outer surface of the cylindrical anchoring portion to further enhance retention. Optionally, a strain relief boot 210 (fig. 1A-1B) may be installed over the crimp ring to provide strain relief and bend control for the optical fiber or fiber optic cable at the point where the optical fiber enters the plug housing of the plug.

In an exemplary aspect, the first and

second housing portions

230, 240 can have a generally open rectangular channel profile with a base 242a and a pair of parallel walls 242b extending from the base, a side wall with a top edge 242c extending along a length of the side wall. When the first and second housing portions are assembled into the plug housing 221, the top edge 232c of the first housing portion 230 is joined to a portion of the top edge 242c of the second housing portion 240.

Referring to fig. 6B-6E, a leaf spring 280 may be attached to the second housing portion 240 of the plug 220 to provide a vertical mating force (represented by directional arrow 92 in fig. 7D) on the bottom surface 172D of the component holder 170 of the receptacle 120. The second housing 240 can include a pair of spaced anchor bars 247 formed on an inner surface 241 of the second housing portion. The leaf spring 280 may fit into the slot 248 formed in the anchor bar to secure the leaf spring to the second housing portion. The leaf spring may have a generally arcuate profile comprising two arcuate arms 282 connected at both ends by a flat foot portion 284. The foot portion fits into a slot formed in the anchor bar to secure the leaf spring to the second housing portion. In an exemplary aspect, the leaf spring may be stamped and formed from a sheet of spring steel.

The plug 220 also includes a fiber alignment mechanism or splice element 260 that is held by an element holder 270. In the exemplary aspect shown in fig. 6A-6E and 7A-7D, the splice element 260 and element holder 270 have the same general structure as splice element 160 and element holder 170, respectively, used in receptacle 120 described above, but a different splice element design may be used, such as the splice elements described in U.S. provisional patent applications 62/544370, 62/573941, and 62/573946, the splice element configuration being incorporated by reference herein.

In this embodiment, the optical fibers may be secured directly to the splice element 260 using an adhesive. For example, the adhesive may be a fast curing UV or visible light initiated adhesive or a heat activated adhesive, or a hot melt material may be utilized to secure the optical fiber array within the comb structure 169 and/or the land area 161a of the splice element. Securing the fiber in this region of the splice element provides the advantage of remotely gripping the fiber, but does not require a separate fiber organizer, such as those provided in plug 120 described above with reference to fig. 2A-2C.

Element holder 270 includes a collar portion 271 attached to element table 272. The collar portion 271 may have a generally cylindrical shape configured to receive a portion of the compression spring 225. As shown in fig. 5A, the collar portion may have an opening 271b through an end wall portion 271d where the element table is attached to the collar portion. The opening allows the optical fiber to pass through the end wall of the grommet-part element holder. The element holder 270 is elastically mounted in the plug housing 221. In an exemplary aspect, a compression spring 225 may be disposed between the plug housing 221 and the component holder to exert a forward force (represented by directional arrow 93 in fig. 6E) on the component holder and the splice component disposed thereon. For example, the plug housing may include a spring seating area 224 formed when the first housing portion 230 and the second housing portion 240 are assembled together.

In an exemplary aspect, the receptacle 120 and the plug 220 may include some common components. For example, ceramic splice elements, element retainers, and leaf springs are used in both the socket 120 and the plug 220. In another exemplary aspect, the socket housing 121, the plug housing 221, and the element holder may be formed through a plastic injection molding process.

With this configuration, the fiber optic connection system 100 can be balanced to control the force of the axial preload on the first and second optical fibers using the spring force of the fiber array in the plug and the receptacle and the main compression spring in the plug.

Fig. 7A to 7D are sectional views showing the plug and the receptacle mated for optical connection. Fig. 7A shows the receptacle 120 and plug 220 oriented toward each other in a pre-mated state. The plug is inserted into the passage 122 at the front end of the receptacle 120a in the direction indicated by directional arrow 90. The second housing portion 240 of the plug travels along a path adjacent the inner surface of the housing portion 140 of the receptacle. The second housing portion 240 of the plug eventually contacts the inner surface of the housing portion 140 of the receptacle, centering the plug within the receptacle, as shown in fig. 7B. As the plug is advanced further into the receptacle (in the direction indicated by directional arrow 90), the receptacle's element retainer 170 is forced between the plug's second housing portion 240 and the plug's element retainer 270. At the same time, the plug's component holder 270 is forced between the receptacle's housing portion 130 and the receptacle's component holder 170, as shown in fig. 7C.

As the plug is moved further into the receptacle, the protrusions 172C, 272C (fig. 5A and 6C) on the

element holders

170, 270 of the receptacle 120 and plug 220 ride along the top surface of the side walls of the element holders of the other connection components, thereby controlling the spacing of the element holders of the

lead splice elements

160, 260 to minimize wear on the terminal ends of the optical fibers prior to fiber-end contact. The leaf springs 180, 280 of the receptacle apply a vertical mating force (represented by directional arrows 92, 92' in fig. 7D) to the back surfaces 172D, 272D of the

element holders

270, 170 of the other connection components. The vertical force is concentrated at the point where the first fiber 54 and the second fiber 54' meet to secure and align the fibers in the alignment channel of the splice element. The combination of the vertical mating forces 92, 92' ensures vertical alignment of the ends of the first and second optical fibers, while the angled walls of the alignment channels in the

splice elements

160, 260 provide lateral alignment of the optical fibers.

In an exemplary aspect, the first and second optical fibers may be mated as a dry splice (i.e., there is no optical coupling material between the end faces of the first and second optical fibers between the first and second optical fibers) to allow for repositioning or re-mating of the plug and receptacle. In alternative embodiments, an optical coupling material, an index-matching gel, or an index-matching adhesive may be used in the optical path.

An exemplary connection according to the present disclosure should have an insertion loss of less than 0.1dB, an acceptable return loss variation when temperature is cycled from-10 ℃ to +60 ℃, and a pull-off strength of greater than 0.451 bf.

The exemplary plug and receptacle connection system may be used in a wide range of applications requiring low loss optical connections. In some embodiments, the exemplary multi-fiber devices may be used in fiber optic cassettes, terminations, patch panels, and the like, where splices may be located in partitions or through walls of the housing.

For example, an exemplary connection system may be used in an optical box, such as described in U.S. provisional patent application 62/544370, which is incorporated herein by reference, wherein the optical box or terminal includes a housing having a top, a bottom, and a plurality of sidewalls disposed between the top and the bottom, and at least one exemplary connection system of the present disclosure disposed through one of the plurality of sidewalls. The plurality of signal paths may exit the cassette or pass through one of the plurality of side walls, wherein the plurality of signal paths may include a connection point at the side wall at which the plurality of signal paths exit the cassette. The exemplary fiber optic connection systems of the present disclosure may be used with multi-fiber connection devices and/or single-fiber connection points. In an exemplary use where a box or terminal may include multiple paired single fiber connection points, such that a first one of the paired single fiber connection points is designated as a transmit port and a second one of the paired single fiber connection points is designated as a receive port. In this aspect, signals carried by the plurality of external optical fibers may be reordered within the cassette or terminal such that the signals exit the cassette in a different order than they enter the cassette. In some embodiments, this reordering of signal paths is used to manage the polarity of the transmit and receive ports.

In an exemplary embodiment, single fiber and/or multi-fiber versions of the receptacle may be provided in the module, while single fiber and/or multi-fiber plugs may be provided on patch cords that may be plugged into receptacles in the module.

Fig. 8A-8C illustrate an alternative fiber optic connection system 300 that provides a ferrule-less interconnection system for optically coupling a plurality of first optical fibers and a plurality of second optical fibers. The fiber optic connection system 300 includes a receptacle 320 and a plug 220 that are each mounted on a terminal end of a fiber optic cable. The plug and receptacle mate together to make an optical connection between an optical fiber of the receptacle's fiber optic cable and an optical fiber in the plug's fiber optic cable. Fig. 8A is an isometric view of the fiber optic connection system 300 in a mated state. Fig. 8B shows the plug 220 inserted into the passageway 322 of the receptacle 320 to form an optical connection, and fig. 8C shows the fiber optic connection system 300 in a mated state, in which the plug 220 is fully inserted into the receptacle 320.

As described herein, the fiber optic connection system 300 is configured as a multi-fiber optical splice connection system configured to connect a first fiber array and a second fiber array. In an exemplary embodiment, the fiber optic connection system is configured to connect two 12-fiber arrays. As will be apparent to one of ordinary skill in the art given the present description, the fiber optic connection system 300 can be modified to include fewer fibers or a greater number of fibers in each fiber array. In one exemplary aspect, the fiber optic connection system 300 can be modified as a single fiber splice connection system.

In general, the receptacle 320 shown in fig. 9A-9D shares many features in common with the receptacle 120 shown in fig. 2A-2D. For example, leaf spring 380, splice member 360, and member retainer 370 are structurally identical to their counterparts in receptacle 120. Accordingly, any reference numbers used hereinafter with reference to these components correspond to the same aspects in the receptacle 120 described above.

The receptacle 320 includes a receptacle housing 321 having a generally tubular forward end 320a including a passageway 322 disposed therein. The passageway is sized to allow insertion of the plug 220 such that a majority of the plug 220 is disposed within the receptacle when the optical connection is made. The plug and receptacle may be secured in a mated state by a mechanical latch or fastener (not shown), or may be permanently attached to each other with an adhesive. The receptacle housing 321 differs from the receptacle housing 121 of the receptacle 120 in that the receptacle housing 321 is longer than the receptacle housing 121, and in that the receptacle housing 321 does not include an integral flange portion as described above. Accordingly, receptacle 320 has a lower profile (smaller cross-section) than receptacle 120, thereby making it useful in high density applications or other applications where a low profile connection is preferred.

For example, a connection system 300 including a socket 320 and plug 120 would be preferred in applications where the connection point needs to be pulled through a catheter or other tight space. The connection system 300 may also be used to repair cables that have been accidentally damaged or cut or other mid-span cable connections that are in an undesirable and/or undesirable flange configuration. In alternative applications, the exemplary fiber optic connection system may be used to prepare a fiber optic harness assembly. For example, the exemplary fiber optic connection system may be used to directly connect a fiber optic fanout to a continuous transmission section or cable in the field or in the factory. This may be particularly advantageous when the fan-out section is made in a first position, the transfer section is made in a second position and the fan-out section to the successive transfer section are put together in a third position.

The longer length of the socket 320 provides space for the compression spring 325 within the socket housing 321. The receptacle housing 321 has a first housing part 330 and a second housing part 340 that can be fixed together to form a receptacle housing, a splice element 360, and a bracket or element holder 370 provided in the receptacle housing. The receptacle housing 321 is configured to arrange and retain the remaining components of the receptacle and protect the exposed bare glass portions 55 of the optical fibers 54 supported within the receptacle. A crimp ring (not shown) may secure the first and second housing portions together. Optionally, latching features (not shown) may be added to further secure the first and second housings. Alternatively, the first and second housing portions may be adhesively bonded together, secured by a snap fit or other latching system. In an alternative embodiment, the socket housing may have a clamshell configuration with a first housing portion and a second housing portion joined by a living hinge.

In an exemplary aspect, the first and

second housing portions

330, 340 can have a generally open rectangular channel profile with a

base

332a, 342a and a pair of

parallel walls

332b, 342b extending therefrom, a side wall having a

top edge

332c, 342c extending along a length of the side wall. When the first and second housing portions are assembled to form the receptacle housing 321 and create the passageway 322 into which a mating plug is to be inserted, the top edge 332c of the first housing portion 330 is joined to a portion of the top edge 342c of the second housing portion 340.

In the exemplary embodiment shown in fig. 9B through 9D, each of the first and

second cases

330, 340 may include a

semi-cylindrical anchor portion

333, 343 formed at their second or rear ends 330B, 340B, respectively. The

semi-cylindrical anchor portions

333, 343 form a cylindrical anchor portion when the first and second housing parts are assembled into the socket housing 321. A crimp ring may be fitted over and secured to the cylindrical anchor portion to anchor a cable jacket or strength member of the fiber optic cable to the receptacle to enhance cable retention strength in the receptacle. Optionally, a strain relief boot 310 may be installed over the crimp ring to provide strain relief and bend control for the optical fibers or fiber optic cables 50 at the point where the optical fibers/fiber optic cables enter the receptacle housing.

Additionally, each of the first and

second housings

330, 340 may include a

well portion

331, 341 disposed adjacent the second end of each housing portion. The well portion forms a retention well for one end of the compression spring 325 when the first housing portion and the second housing portion are assembled together. The second end of the compression spring fits into the collar portion 371 of the element holder 370 so that the compression spring can exert a forward force (indicated by directional arrow 93 in fig. 9D) on the element holder and the splice element disposed thereon.

With this receptacle configuration, the fiber optic connection system 300 can utilize the spring force of the fiber array and the primary compression springs in the plug and receptacle to achieve a force balance sufficient to control the axial preload on the first and second optical fibers.

Referring to fig. 9B and 9D, a leaf spring 380 may be attached to the first housing portion 340 of the receptacle 320 to provide a vertical mating force (represented by the directional arrow in fig. 8C) on the bottom surface 272D of the element holder 270 of the mating plug 220. In an exemplary aspect, the first housing portion 330 includes a pair of spaced anchor rods 337 formed on an inner surface 331 of the second housing portion. The leaf spring 380 may fit into a slot formed in the anchor bar to secure the leaf spring to the first housing portion.

The element holder 370 includes a collar portion 371 that is attached to the element table 372. In some embodiments, collar portion 371 may have a generally cylindrical shape configured to receive a portion of a compression spring. The splice member is disposed on the component table of the component holder as previously described with respect to splice member 160 and component holder 170 shown in fig. 5A and 5B.

The collar portion 371 may also include detents 371c extending from the outer surface of the collar portion on either side of the collar portion. A translation gap 379 is formed between the brake pawl and the end of element table 372. When two of the example receptacles 320 are mated together, the tapered

ridges

339, 349 disposed on the inner surfaces of the first and

second housing portions

330, 340 form a track that fits in the translation gap 379 to control the relative vertical position of the element holder 370.

As with the previous embodiments, the fiber optic connection system 300 includes a plug 220 and a receptacle 320 that may be field terminated or installed in the field onto a fiber optic cable or ribbon and then assembled to form a semi-permanent or permanent optical connection. Alternatively, the plug 220 and receptacle 320 may each be factory terminated, installed or mounted onto a fiber optic cable or ribbon and assembled together in the field for optical connection.

The connection system includes: a receptacle comprising a first splice member configured to hold and align a plurality of first fibers of a first fiber array, and a receptacle housing having an internal passage for holding the first splice member; and a plug including a second splice member for holding at least a plurality of second fibers of the second fiber array, and a plug housing for holding the second splice member. An optical connection is made between a first optical fiber in the first optical fiber array and a second optical fiber in the second optical fiber array by inserting the plug into the internal passageway of the receptacle. In an exemplary aspect, the first splice member and the second splice member each include a splice body having a plurality of alignment channels formed in a top surface of the splice body to guide, align, and/or hold optical fibers from the first optical fiber array and the second optical fiber array, respectively.

In some aspects of any of the foregoing embodiments, the receptacle may include a flange extending from an exterior surface of the receptacle housing to connect the receptacle to one of a patch panel bulkhead or a wall in a fiber optic module.

In some aspects of any of the foregoing embodiments, the first splice member and the second splice member are structurally equivalent. The plurality of alignment channels of the first splice member and the second splice member can extend from the first end to the second end of the splice body.

In some versions of any one of the preceding embodiments, wherein the first splice member and the second splice member are formed from a low coefficient of thermal expansion silica material. In some cases, the low coefficient of thermal expansion silica material is a net shape cast and cured silica material.

The receptacle of any of the foregoing embodiments may further comprise a first element retainer for retaining the first splice element in the plug housing, and/or the plug of any of the foregoing embodiments may further comprise a second element retainer for retaining the second splice element in the plug housing. In some aspects, the first element holder and the second element holder are structurally equivalent.

The plug of any of the foregoing embodiments may further include a second compression spring disposed between the plug housing and the second element retainer to exert a forward force on the second splice element, and/or the receptacle of any of the foregoing embodiments may further include a first compression spring disposed between the receptacle housing and the first element retainer to exert a forward force on the first splice element. The plug and receptacle may be force balanced to control axial preload on the first optical fiber and the second optical fiber. For example, in one aspect, the force balance is provided by a second compression spring disposed in the plug and spring forces of the first and second fiber arrays disposed in the receptacle and plug, respectively. Alternatively, the force balance is provided by spring forces of a first compression spring disposed in the receptacle, a second compression spring disposed in the plug, and first and second fiber arrays disposed in the receptacle and plug, respectively. In another aspect, the force balance is provided by spring forces of a first compression spring disposed in the receptacle and a first fiber array and a second fiber array disposed in the receptacle and the plug, respectively.

In any of the preceding embodiments, the optical coupling material is disposed between the ends of the first array of optical fibers and the second array of optical fibers in the connection system.

In an exemplary aspect, both the plug and the receptacle of the connection system of any of the preceding embodiments are ferrule-less.

Various modifications, equivalent processes, as well as numerous structures to which the present invention may be applicable will be readily apparent to those of skill in the art to which the present invention is directed upon review of the present specification.

Claims

1. A ferrule-less fiber optic connection system configured to interconnect a first fiber array and a second fiber array, wherein the first fiber array and the second fiber array each include two or more optical fibers, the connection system comprising:

a receptacle including a first splice element configured to hold and align a plurality of first fibers of the first fiber array, and a receptacle housing having an internal passageway for holding the first splice element;

a plug including a second splice element for holding at least a plurality of second fibers of the second fiber array, and a plug housing for holding the second splice element,

wherein inserting the plug into the internal passageway of the receptacle to make an optical connection is made between the first optical fiber of the first optical fiber array and the second optical fiber of the second optical fiber array; and is

Wherein at least one of the first splice member and the second splice member each comprise a splice body having a plurality of fiber alignment channels formed in a top surface of the splice body.

2. A ferrule-less fiber optic connection system configured to interconnect a first fiber array and a second fiber array, wherein the first fiber array and the second fiber array each include two or more optical fibers, the connection system comprising:

a receptacle including a first splice element configured to hold a plurality of first fibers of the first fiber array, and a receptacle housing having an internal passageway for holding the first splice element;

a plug including a second splice element for holding and aligning at least a plurality of second optical fibers of the second optical fiber array, and a plug housing for holding the second splice element,

3. The connection system of any one of claims 1 and 2, wherein the receptacle includes a flange extending from an exterior surface of the receptacle housing to connect the receptacle to one of a patch panel bulkhead or a wall in a fiber optic module.

4. The connection system of any one of the preceding claims, wherein the first splice element and the second splice element are structurally equivalent.

5. The connection system of any one of the preceding claims, wherein the plurality of alignment channels extend from a first end to a second end of the splice body.

6. The connection system of any one of the preceding claims, wherein the first splice member and the second splice member are formed of a low coefficient of thermal expansion silica material.

7. The connection system of claim 6, wherein the low coefficient of thermal expansion silica material is a net shape cast and cured silica material.

8. The connection system of any one of the preceding claims, wherein the plug further comprises a second element retainer for retaining the second splice element in the plug housing.

9. The connection system of any one of the preceding claims, wherein the receptacle further comprises a first element retainer for retaining the first splice element in the plug housing.

10. The connection system of claim 8, wherein the first and second element retainers are structurally equivalent.

11. The connection system of any one of the preceding claims, wherein the plug further comprises a second compression spring disposed between the plug housing and the second element retainer to exert a forward force on the second splice element.

12. The connection system of any one of the preceding claims, wherein the socket further comprises a first compression spring disposed between the socket housing and the first element holder to exert a forward force on the first splice element.

13. The connection system of any one of the preceding claims, wherein the plug and the receptacle are force balanced to control axial preload on the first and second optical fibers.

14. The connection system of any one of the preceding claims, wherein the force balance is provided by a second compression spring disposed in the plug and spring forces of the first and second fiber arrays.

15. The connection system of any one of the preceding claims, wherein the force balance is provided by a first compression spring disposed in the plug, a second compression spring disposed in the receptacle, and spring forces of the first and second fiber arrays.

16. The connection system of any one of the preceding claims, further comprising an optical coupling material disposed between an end of the first optical fiber array and an end of the second optical fiber array.

17. The connection system of any one of the preceding claims, wherein both the first splice member and the second splice member each comprise a splice body having a plurality of fiber alignment channels formed in a top surface of the splice body.