WO2022197952A1

WO2022197952A1 - Nonintrusive tap monitoring in integrated optical waveguide structure

Info

Publication number: WO2022197952A1
Application number: PCT/US2022/020794
Authority: WO
Inventors: Jan Watté; Cristina LERMA ARCE; Jan Jozef Julia Maria ERREYGERS
Original assignee: Commscope Technologies Llc
Priority date: 2021-03-19
Filing date: 2022-03-17
Publication date: 2022-09-22

Abstract

An optical device includes a substrate and a plurality of waveguides on the substrate. Each waveguide of the plurality of waveguides has a first end at a first multifiber port on the substrate and a second end at one of a plurality of fiber ports. The first multifiber port is associated with a first fiber count and each of the plurality of fiber ports has an associated fiber count less than the first fiber count. A first of the waveguides has an associated first tap waveguide to tap a portion of an optical signal propagating along the first waveguide as a first tap signal. The first tap signal is directed to an out-of-plane reflector in the substrate that reflects the first tap signal received from the first tap waveguide out of the plane of the substrate to a detector.

Description

NONINTRUSIVE TAP MONITORING IN INTEGRATED OPTICAL WAVEGUIDE STRUCTURE

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is being filed on March 17, 2022 as a PCT International Patent Application and claims the benefit of U.S. Patent Application Serial No. 63/163,538, filed on March 19, 2021, the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The present invention relates generally to optical fiber communication and more specifically to the methods and systems for monitoring optical signals at a fiber distribution point.

BACKGROUND

[0003] Optical fiber communications are used to communicate between devices in data centers or optical local area networks. Many devices employ a single fiber input or output, which can lead to the use of a large number of single fibers cables. In order to reduce the number of single fiber cables, signals are often carried over the greater part of the communication distance by multifiber cables, with single fiber cables being used to carry the signals the last part of the communication path.

[0004] An exemplary communications system 100 is schematically illustrated in FIG. 1. A first location 102 includes a first set of devices 104 that have a number of single fiber outputs. The devices 104 are connected to a second set of devices 106 at a second location 108. Instead of connecting the devices 104 to the devices 106 by multiple single fiber cables, the connection is made via a single multifiber cable 110. Single fibers 112 from the devices 104 at the first location are connected to a first fiber connector module 114 in which the single fibers 112 are connected to respective fibers in the multifiber cable 110 by fibers within the housing of the module 114. At the second location 108, the multifiber cable 110 is connected to a second fiber connector module 116, in which the fibers of the multifiber cable 110 are connected to respective single fibers 118 by fibers within the housing of the module 116 to connect to respective devices 106. [0005] FIG. 2 schematically illustrates an exemplary fiber connector module 200, showing a multifiber cable 202 connected via a multifiber connector 204 at a multifiber port 205, such as an MPO connector, to multiple single fibers 206 with another MPO connector and an intermediate adapter, within the housing 208 of the fiber connector module 200. The single fibers 206 are stored within the housing 208 in a coil or loop 210 and each fiber 206 is coupled to a single fiber connector 212 at a single fiber port 213, with another single fiber connector and an intermediate adapter on the wall of the housing 208. Single fiber cables 214 are connected to the single fiber connectors 212 to carry the signals from their respective single fibers 206.

[0006] Because of the need to coil the single fibers 206 within the housing 208, the footprint of the fiber connector module 200 is large. Furthermore, there is no opportunity to tap any of the signals within the single fibers 206 to monitor that the optical channels of the communication system are operable. There is, therefore, a need for a connector module having a smaller footprint and also one that provides the ability to monitor for optical signal activity.

SUMMARY

[0007] The present invention relates generally to an apparatus for connecting a multifiber cable to other fiber cables having a fiber count less than the fiber count of the multifiber cable.

[0008] One embodiment of the invention is directed to an optical device that includes a substrate. There is a plurality of plurality of waveguides on the substrate. Each waveguide of the plurality of waveguides has a first end at a first multifiber port on the substrate and a second end at one of a plurality of fiber ports. The first multifiber port is associated with a first fiber count and each of the plurality of fiber ports has an associated fiber count less than the first fiber count.

[0009] A first of the plurality of waveguides has an associated first tap waveguide on the substrate to tap a portion of an optical signal propagating along the first waveguide as a first tap signal. The first tap waveguide terminates proximate a first out-of-plane reflector in the substrate that reflects the first tap signal received from the first tap waveguide out of the plane of the substrate. A first detector element is positioned to detect the reflected first tap signal from the first out-of-plane reflector. BRIEF DESCRIPTION OF THE DRAWINGS [0010] The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:

[0011] FIG. 1 schematically illustrates an embodiment of a prior art communications system;

[0012] FIG. 2 schematically illustrates an embodiment of a fiber connector module, which permits coupling of multiple single fibers to a single multifiber cable;

[0013] FIG. 3 schematically illustrates an embodiment of an integrated connector module, which permits coupling of multiple single fibers to a single multifiber cable and provides the ability to monitor signals passing within the integrated connector module, according to an embodiment of the present invention;

[0014] FIG. 4 schematically illustrates an approach for edge coupling fibers to an integrated connector module chip, according to an embodiment of the present invention.

[0015] FIG. 5 schematically illustrates another approach for edge coupling fibers to an integrated connector module chip, according to another embodiment of the present invention;

[0016] FIGS. 6A-6C schematically illustrate steps in fabricating a waveguide in a polymer optical chip platform according to an embodiment of the present invention;

[0017] FIG. 7 schematically illustrates a cross-sectional view of part of an integrated connector module chip showing an out-of-plane reflector disposed to reflect a tap signal on a tap waveguide to a detector located on a surface of the chip, according to an embodiment of the present invention;

[0018] FIGS. 8A-8D schematically illustrate cross-sectional views of part of an integrated connector module chip showing process steps for fabricating an out-of-plane reflector having a front surface reflector, according to an embodiment of the present invention; [0019] FIG. 9 schematically illustrates a cross-sectional view of part of an integrated connector module chip showing a focusing element written at an output of the tap waveguide, according to an embodiment of the present invention;

[0020] FIG. 10 schematically illustrates a cross-sectional view of part of an integrated connector module chip having an out-of-plane reflector having a total internally reflecting surface, according to an embodiment of the present invention;

[0021] FIG. 11 schematically illustrates an embodiment of an integrated connector module, which permits coupling of multiple single fibers to a single multifiber cable and provides the ability to monitor signals passing within the integrated connector module, according to another embodiment of the present invention;

[0022] FIG. 12 schematically illustrates an embodiment of an integrated connector module, which permits coupling of multiple single fibers to a single multifiber cable and provides the ability to monitor signals passing in both directions within the integrated connector module, according to another embodiment of the present invention;

[0023] FIG. 13 schematically illustrates a cross-sectional view of part of an integrated connector module chip having an out-of-plane reflector having a lens disposed between the out-of-pane reflector and the detector element, according to an embodiment of the present invention; and

[0024] FIG. 14 schematically illustrates a cross-sectional view of part of an integrated connector module chip having a curved out-of-plane reflector that focused the tap optical signal to its respective detector element, according to an embodiment of the present invention.

[0025] 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 spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION

[0026] The present invention is generally directed to an improved connector module that is based on the use of an integrated optics platform that can provide an optical monitoring capability.

[0027] FIG. 3 schematically illustrates components of an integrated connector module 300 that is based on an integrated optical chip 302 that distributes signals between a multifiber cable 304 and a plurality of single fiber cables 306. The optical chip 302 may be located within a housing 308 (dashed lines). The multifiber cable 304 is terminated with a multifiber connector 310, for example an MPO connector, and the integrated optical chip 302 is provided with a multifiber connector receptacle (adapter) 312 so that the fibers within the multifiber cable 304 are coupled to the first ends 316 of respective waveguides 314 at the multifiber port 315 on the integrated optical chip 302. The multifiber port 315 includes the output ends of the waveguides 314 that couple to the multifiber cable 304. The waveguides 314 fan out from their first ends 316 at the multifiber connector receptacle 312 to respective single fiber connector receptacles (adapters) 318 at their second ends 320, at single fiber ports 321. The single fiber ports 321 include the output ends of the waveguides 314 that couple to single fiber cables 306. The single fiber cables 306 are connected to respective single fiber receptacles 318 by single fiber connectors 322. The single fiber connectors 322 and receptacles 318 may be, for example, FC, LC, SC connectors or the like.

[0028] Each of the waveguides is provided with an associated tap waveguide 324 that taps off a portion of the optical signal in the waveguide 314 as a tap signal. A tap detector 326 detects the tap signal on the tap waveguide 324 to enable monitoring of the optical signal passing along the associated waveguide 314. For clarity, not every waveguide 314, waveguide first end 316, single fiber receptacle 318, waveguide second end 320, single fiber connector 322, tap waveguide 324 or tap detector 326 in the figure has been labeled with a number.

[0029] One approach to connecting the fiber cables to an integrated optical chip 402 is schematically illustrated in FIG. 4. The illustrated embodiment includes an integrated optical chip 402 that has four waveguides 414 fanning out from their first ends 416, at the multifiber port 417 that may be coupled to a multifiber cable, to second ends 420, at the single fiber ports 421, where they are coupled to respective single fiber cables 406. Sleeves 430, each having a slot 432 facing the optical chip 402 are slid onto the optical chip 402 at the second ends of each waveguide 414. The sleeves 430 fit into recesses on a connector body (adapter) 434 that accommodates the sleeves 430. The sleeves 430 and connector body 434 together form single fiber receptacles that receive single fiber cables 406 having a connector end 422, for example an LC connector, and SC connector or the like. This approach of connecting fiber cables to a substrate, along with others, is described in greater detail in U.S. Patent No. 9,846,283, which is incorporated herein by reference.

[0030] Another approach to connecting a single fiber cable to a single fiber port on an integrated optical chip 502 is schematically illustrated in FIG. 5. In this approach, a groove 508 is etched at the edge 510 of the chip 502 and the fiber 512 of the single fiber cable, stripped of the cable covering, is mounted within the groove 508. The groove 508 is dimensioned and positioned such that the core of the fiber 512, when mounted within the groove 508, is aligned with a respective waveguide 514 at its fiber port 521 on the optical chip 502. A cover 516 (shown in broken lines) may be positioned over the fiber 512 to help stabilize its position relative to the optical chip 502. The groove 508 may have any suitable shape. For example, the illustrated embodiment of groove 508 is U-shaped, but it may take on different shapes, such as a v-groove, or a semicylindrical groove. In other approaches, a fiber may be located in a grooved alignment block that is attached at the substrate edge or that is integral to the substrate. Additionally, multiple fibers 512 adjacent to each other in respective grooves may be coupled to the optical chip 502 at a multifiber port.

[0031] The optical integrated chip may be fabricated in any suitable platform including, for example a glass such as silica, a semiconductor such as silicon, silicon nitride, indium phosphide or the like, or a polymer such as a polyboard. In the silica platform, waveguides may be formed by conventional processes, such as diffusion or ion implantation through a mask, or via femtosecond two photon laser writing. In semiconductor platforms, multiple layers of semiconductor material are deposited on a substrate, typically a silica substrate, and waveguides may be formed via etching through a mask and regrowth to form the cladding layers. The polyboard platform includes layers of polymer spun on a substrate, for example a silica substrate. The layers of polymer may be formed using single polymers or polymer blends so as to tune the desired refractive index of each layer. Examples of polymers that may be used include Ormocore and Ormoclad polymers having respective first and second refractive indices, available from micro resist technology GmbH, Berlin, Germany. The two polymers may be used in a blend with the ratio of the two polymers selected to produce a refractive index in the range between first and second refractive indices.

[0032] FIGS. 6A-6C schematically illustrate fabrication steps for waveguides in a polymer platform using lithographic processes, as may be used to form an integrated optical chip for an integrated connector module. FIG. 6A illustrates a substrate 602 with a buffer layer 604, or lower cladding layer and a core layer 606. The substrate 602 may be a silica substrate, and the buffer layer 604 and core layer may be formed of polymers sequentially spin-coated and cured on the substrate 602. A mask 608 is deposited on the core layer 606, defining areas to be etched. The mask 608 may be formed by spin-coating mask material on top of the core layer 606, and then UV curing the mask material through a mask. After a subsequent washing step, those parts of the mask material that were exposed to the UV light remain on the core layer 606 as the mask 608, while those parts of the mask material that were shaded by the mask so as not to be exposed to the UV light are washed away.

[0033] The core layer 606 is etched through the mask 608 and then the mask 608 is removed, leaving the waveguide 610, as shown in FIG. 6B. A cladding layer 612 may then be deposited over the waveguide 610, as shown in FIG. 6C. The cladding layer 612 may be formed by spin-coating over the buffer layer 604 and the waveguide 610. A similar structure, having a waveguide surrounded above, below and at the sides by cladding material may also be formed in a semiconductor platform.

[0034] One approach to detecting the optical signal propagating along a tap waveguide in the integrated connector module is schematically illustrated in FIG. 7. The figure shows a side view through part of the optical integrated chip 702, showing the substrate 704, the buffer layer 706, the tap waveguide 708 and the cladding layer 710. An out-of-plane reflector 712 intersects the tap waveguide 708 so that the tap signal 714, propagating from the tap waveguide 708, is directed out of the plane of the chip 702 to a tap signal detector unit 716. In the illustrated embodiment the tap signal detector unit 716 comprises a substrate with the detector element 718 mounted to the substrate.

[0035] The tap signal detector unit 716 may include any suitable detector element 718 for detecting the tap signal, for example a semiconductor photodiode. For example, where the tap signal 714 is in the wavelength range of 1520-1650 nm, the detector element 718 may be an InP or InGaAs photodiode. The tap signal detector unit 716 may include the detector element 718 in a flip-chip configuration, as illustrated, so that the detector element 718 is directly facing the out-of-plane reflector 712. In other embodiments, the tap signal 714 may pass through the substrate of the detector unit 716 before being incident on the detector element 718.

[0036] In some embodiments the out-of-plane reflector 712 may be oriented at 45° relative to the plane of the waveguide 708 so as to direct the tap signal 714 in a direction substantially perpendicular to the plane of the waveguide 708. In other embodiments, the out-of-plane reflector 712 may be oriented at some angle other than 45°, but at an angle sufficient that the reflected tap signal 714 is directed out of the chip to the tap signal detector unit 716.

[0037] The angled surface of the out-of-plane reflector 712 may be fabricated using any suitable technique. In one approach, the angled surface may be formed by micromachining with a dicing saw. A reflective coating may then be deposited on the resulting angle surface to provide the angled reflector of the out-of-plane reflector 712.

[0038] Another approach, described with reference to FIGs. 8A-8D, uses photolithographic methods and may lead to higher precision reflectors. FIG. 8A schematically illustrates a cross-sectional view of part of an integrated optical chip 802 having a substrate 804, buffer layer 806, tap waveguide 808 and cladding layer 810. A mask 812 is formed over the cladding layer to define the area where the reflector is to be formed. A well 814 is etched through the mask, as is schematically illustrated in FIG. 8B, using any suitable etching method. In a silica or semiconductor platform, the well 814 may be etched using wet etching or reactive ion etching (RIE). In a polymer platform the well 814 may be etched using RIE.

[0039] An angled structure 826 may be fabricated in the well 814 using 3D, two-photon femtosecond laser writing in a transparent photoresist. One approach to doing this, schematically illustrated in FIG. 8C, is to fill the well 814 with unexposed resist 816. Light 818 from a femtosecond laser system 820 is focused into the resist using a focusing system 822, which may include one or more lenses, mirrors, or combinations thereof. The resist 816 is exposed at the focus 824 of the light 818 via two photon absorption. The position of the focus 824 is moved relative to the position of the substrate 804 in the x, y, and z directions (the x and z axes are in the plane of the figure, the y axis is directed into the figure). The photoresist 816 is exposed as the focus 824 moves raster fashion within the well 814, building up the angled structure 826, as is schematically shown in FIG. 8D, to have an out-of-plane reflector 828. Light from the waveguide 808 may be reflected by the out-of-plane reflector 828. In other embodiments, a reflective coating 830, for example a metal coating or multilayer dielectric coating, may be included on the out-of-plane reflector 828. In this case, the reflective coating 830 may be considered to be a front surface reflector for reflecting the light 832 from the waveguide 808.

[0040] In some embodiments, a focusing element 834 may be 3D written on the end of the waveguide 808, as is schematically illustrated in FIG. 9. The focusing element 834 may be fabricated using same the 3D, two-photon femtosecond laser writing process as was used to fabricate the angled structure 826. In other embodiments, a focusing element 834 may be adhered in place at the end of the waveguide 808 after the angles structure 826 has been fabricated. The focusing element 834 may reduce the divergence of the light 832 propagating from the waveguide 808, which may aid in detecting the tap signal.

[0041] In another approach, the reflecting structure 826 may be fabricated with the out- of— plane reflector 828 oriented in such a way as to reflect the light 832 from the waveguide 808 down through the buffer layer 808 to the substrate 802, as is schematically illustrated in FIG. 10. In some embodiments, the out-of-plane reflector 828 may operate as a total internally reflecting (TIR) surface. In other embodiments, the out-of-plane reflector 828 may be provided with a reflective coating. A tap signal detector unit 836, having a detector element 838, may be provided below the substrate 802 to detect the light 832 reflected at angled surface 828 after passing through the substrate 802.

[0042] Another approach to reducing the divergence of the light propagating from the waveguide 808 is schematically illustrated in FIG. 13. In this embodiment, a microlens is disposed above the out-of-plane reflector 828to reduce the divergence of the light 832 reflected at the out-of-plane reflector 828. This may be advantageous when the detector unit 1302 containing the detector element 1304 is not mounted close to the surface of the chip, for example when the detector unit 1302 is mounted to the housing of the integrated connector module. A microlens may also be used in an arrangement where the angled surface is a TIR surface, and the light from the waveguide is directed through the substrate, for example as illustrated in FIG. 10. In such a case the microlens is positioned between the substrate 802 and the detector unit. Such an arrangement may permit the detector unit to be placed at a distance from the substrate 802.

[0043] Another approach to reducing the divergence of the light propagating from the waveguide 808 is schematically illustrated in FIG. 14. In this embodiment, the out-of-plane reflector 828 is curved so that when light is reflected by the out-of-plane reflector 828 its divergence is reduced. The curve to the out-of-plane reflector 828 may be introduced during the femtosecond laser two photon 3D printing process used to fabricate the out-of-plane reflector 828. Although the figure only shows that the angled surface 828 is curved with a radius of curvature in the plane of the figure, it will be appreciated that the angle surface 828 may be formed to be curved in two dimensions, for example with a spherical, aspherical or paraboloidal shape, so as to be able to reduce the divergence of the light 832 in two dimensions. In some embodiments the light 832 may be collimated following reflection at the out-of-plane reflector 828, or may come to a focus. This may be advantageous when the detector unit 1302 containing the detector element 1304 is not mounted close to the surface of the chip, for example when the detector unit is mounted to the housing of the integrated connector module. A curved angled surface may also be used in an arrangement where the angled surface is a TIR surface, and the light from the waveguide is directed through the substrate, for example as illustrated in FIG. 10. Such an arrangement may permit the detector unit to be placed at a distance from the substrate 802.

[0044] In some embodiments, each tap waveguide may be associated with its own out- of plane reflector in a respective well, with a respective detector placed appropriately to detect the tap signal reflected by the out-of-plane reflector. In other embodiments two or more tap waveguides may feed to a out-of-plane reflector, thus permitting a detector unit to include two or more respective detector elements. FIG. 11 shows an embodiment of an integrated connector module 1100 that includes a chip 1102, for distributing distributes signals between a multifiber cable 1104 and a plurality of single fiber cables 1106. The multifiber cable 1104 is terminated with a multifiber connector 1110, for example an MPO connector, and the integrated optical chip 1102 is provided with a multifiber connector receptacle 1112 so that the fibers within the multifiber cable 1104 are coupled to the first ends 1116 of respective waveguides 1114 at the multifiber port 1115 on the integrated optical chip 1102. The multifiber port 1115 includes the output ends of the waveguides 1114 that couple to the multifiber cable 1104. The waveguides 1114 fan out from their first ends 1116 at the multifiber connector receptacle 1112 to respective single fiber connector receptacles 1118 at their second ends 1120, at single fiber ports 1121. The single fiber ports 1121 include the output ends of the waveguides 1114 that couple to single fiber cables 1106. The single fiber cables 1106 are connected to respective single fiber receptacles 1118 by single fiber connectors 1122. The single fiber connectors 1122 and receptacles 1118 may be, for example, FC, LC, SC connectors or the like.

[0045] Each of the waveguides is provided with an associated tap waveguide 1124 that taps off a portion of the optical signal in the waveguide 1114 as a tap signal. The tap waveguides 1124 each couple to a multi-element detector unit 1126 that contains respective detector elements 1128 for each tap waveguide 1124. For example, the multi-detector unit 1126 may include a substrate to which are mounted different photodiode detector elements 1128. The multi-element detector unit 1126 is disposed above an angled reflector 1130 in a trench 1132. The angled reflector 1130 reflects light from two or more tap waveguides 1124 to their respective detector elements 1128. If a microlens arrangement is used to reduce the divergence of the light propagating from the tap waveguide 1124 to its respective detector element 1128, in a manner like that described with reference to FIG. 13, a microlens array may be used between the multi-element detector unit 1126 and the angled reflector 1130 to direct each beam from each tap waveguide 1124 to its respective detector element 1128. If a curved out-of-plane reflector 828 is used to reduce the divergence of the light propagating from the tap waveguide 1124 to its respective detector element 1128, in a manner like that described with reference to FIG. 14, the curved out-of-plane reflector 828 may be provided with separately curved reflecting portions to focus each beam from each tap waveguide 1124 to its respective detector element 1128.

[0046] In this embodiment, some tap waveguides 1124 may cross a waveguide 1114 at a waveguide crossing 1134. In the illustrated embodiment, some multi-element detector units 1126 include four detector elements 1128 while others include two detector elements 1128. In other embodiments, the multi-element detector units 1126 may include different numbers of detector elements 1128.

[0047] In the illustrated embodiment the trenches 1132 and their associated angled reflectors 1130 extend inwards to the chip 1102 from the chip edge 1136. This arrangement may be used, for example, if the trenches 1132 are formed by micromachining with a dicing saw, although it may also be used where the trenches are formed by etching. It should be understood that there is no requirement for an angled reflector 1130 in a trench 1132, used in conjunction with a multi-element detector unit 1126, extend to the edge of the chip 1102.

[0048] In some embodiments, the integrated connector module connects a fiber cable having a first fiber count to two or more other fiber cables each having a lower fiber count. For example, in the embodiment illustrated in FIG. 11, the multifiber cable 1104 has a fiber count of 12, and is connected to twelve fiber cables each with a fiber count of one. In some embodiments, the lower count fiber cables contain more than one fiber, such as two or four. As an example, a cable with a fiber count of 12 may be coupled to three fiber cables, each with a fiber count of four. In the exemplary embodiment schematically illustrated in FIG. 12, the integrated connector module 1200 has an integrated optical chip 1202 that couples a first multifiber cable 1204 having a fiber count of eight to three other multifiber cables, two of the multifiber cables 1206a having a fiber count of two and the third multifiber cable 1206b having a fiber count of four 1102. The first multifiber cable 1204 is terminated with a multifiber connector 1210, for example an MPO connector, having a fiber count of eight, and the integrated optical chip 1202 is provided with a multifiber connector receptacle 1212, having a fiber count of eight, so that the fibers within the first multifiber cable 1204 are coupled to the first ends 1216 of respective waveguides 1214 at the first multifiber port 1215 on the integrated optical chip 1102. The multifiber port 1215 includes the output ends of the waveguides 1214 that couple to the fibers of the first multifiber cable 1204. The waveguides 1214 fan out from their first ends 1216 at the first multifiber connector receptacle 1212 to respective connector receptacles 1218a, 1218b at their second ends 1220, at fiber ports 1221. The fiber ports 1221 include the output ends of the waveguides 1214 that couple to the fibers in multifiber fiber cables 1206a, 1206b. The multifiber cables 1206a, 1206b are connected to respective multifiber receptacles 1218a, 1218b by multifiber connectors 1222a, 1222b. The multifiber connectors 1222a, 1222b and receptacles 1218a, 1218b may be, for example, MPO connectors or the like.

[0049] In the illustrated embodiment, each of the waveguides 1214 is provided with associated tap waveguides 1224a, 1224b that tap off a portion of the optical signals propagating in different directions along the waveguide 1214. Tap waveguide 1224a carries a tap signal derived from the optical signal propagating from the first end 1216 of the waveguide 1214 to the second end 1220 of the waveguide 1214. Tap waveguide 1224b carries a tap signal derived from the optical signal propagating from the second end 1220 of the waveguide 1214 to the first end 1216 of the waveguide 1214. The tap waveguides 1224a, 1224b each couple to a respective detector element 1228 so that the tap signals can be detected. In the illustrated embodiment, the detector elements 1228 are located in multi element detector units 1226. The multi-element detector units 1226 are disposed above an out-of-plane reflector in a trench (not shown). The out-of-plane reflector reflects light from the incident tap waveguides 1224a, 1224b to their respective detector elements 1228. In some embodiments, for example as illustrated in FIG. 12, the tap waveguides 1224a, 1224b associated with a particular waveguide 1214 may be connected to each other. In other embodiments, the tap waveguide 1224a, 1224b are not connected to each other. In some embodiments, some tap waveguides 1224a, 1224b may cross a waveguide 1214 at a waveguide crossing 1234. In the illustrated embodiment, the multi-element detector units 1226 include four detector elements 1228. In other embodiments, the multi-element detector units 1226 may include different numbers of detector elements 1228. For example, the pair of waveguides 1214 associated with a single multifiber connector 1222a may be associated with tap waveguides 1224a, 1224b whose signals are detected by detector elements 1228 in two separate, two-element multi-element detector units 1226.

[0050] The waveguides in the integrated connector units described herein may be formed using any suitable method. For example, in a glass substrate the waveguides may be formed using lithographic techniques, including diffusion and implantation through lithographically masked regions of the substrate surface, or by 3D femtosecond laser processing. In semiconductor substrates, such as silicon substrates, waveguides may be made using standard semiconductor lithographic techniques to form waveguides, including buried waveguides, surface waveguides and ridge waveguides. A waveguide may be described as being on a substrate if it is formed within the substrate, for example via doping a part of the substrate, or if it is disposed within a layer on top of the substrate. The layer containing the waveguide need not be directly on the substrate surface, but there may be one or more intervening layers between the waveguide and the substrate. The intervening layers and any layers above the waveguide may also be described as being on the substrate.

[0051] It will be appreciated that in many optical devices optical signals may propagate through the device in opposing directions. For example, in one direction a tap may operate to split out a portion of the main optical signal propagating from multifiber port to a single fiber port. Accordingly, although various waveguides, fibers, and ports may be labeled as “input” and “output” in this description, it should be understood that these labels are used only for ease of description. It should be understood that the waveguides, optical fibers and ports described herein may operate as inputs for optical signals propagating in one direction but as outputs for signals operating in the opposite direction.

[0052] 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. The claims are intended to cover such modifications and devices.

[0053] As noted above, the present invention is applicable to fiber optical communication and data transmission systems. Accordingly, the present invention should not be considered limited to the particular examples described above, but rather should be understood to cover all aspects of the invention as fairly set out in the attached claims.

Claims

What is claimed is:

1. An optical device, comprising: a substrate; a plurality of waveguides on the substrate, each waveguide of the plurality of waveguides having a first end at a first multifiber port on the substrate and a second end at one of a plurality of fiber ports, the first multifiber port being associated with a first fiber count and each of the plurality of fiber ports having an associated fiber count less than the first fiber count; a first of the plurality of waveguides having an associated first tap waveguide on the substrate to tap a portion of an optical signal propagating along the first waveguide as a first tap signal, the first tap waveguide terminating proximate a first out-of-plane reflector in the substrate that reflects the first tap signal received from the first tap waveguide out of the plane of the substrate; and a first detector element positioned to detect the reflected first tap signal from the first out-of-plane reflector.

2. The optical device as recited in claim 1, wherein a second of the plurality of waveguides has an associated second tap waveguide on the substrate to tap a portion of an optical signal propagating along the second waveguide as a second tap signal, the second tap waveguide terminating proximate a second out-of-plane reflector in the substrate that reflects the second tap signal received from the second tap waveguide out of the plane of the substrate, and a second detector element unit positioned to detect the reflected second tap signal from the second out-of-plane reflector.

3. The optical device as recited in claim 2, wherein the first out-of-plane reflector is disposed within a first well in the substrate and the second out-of-plane reflector is disposed within a second well in the substrate.

4. The optical device as recited in claim 2, wherein the first out-of-plane reflector is disposed within a first well in the substrate and the second out-of-plane reflector is disposed within the first well.

5. The optical device as recited in claim 4, wherein the first detector element and the second detector element are disposed in a first detector unit.

6. The optical device as recited in claim 4, wherein the first out-of-plane reflector comprises the second out-of-plane reflector.

7. The optical device as recited in claim 4, wherein the second tap waveguide crosses the first waveguide.

8. The optical device as recited in claim 2, wherein a third of the plurality of waveguides has an associated third tap waveguide on the substrate to tap a portion of an optical signal propagating along the third waveguide as a third tap signal, the third tap waveguide terminating proximate a third out-of-plane reflector in the substrate that reflects the optical signal received from the third tap waveguide out of the plane of the substrate, and a third detector element positioned to detect the reflected third tap signal from the third out-of-plane reflector.

9. The optical device as recited in claim 8, wherein the first out-of-plane reflector is disposed within a first well in the substrate, the second out-of-plane reflector is disposed within the first well and the third out-of-plane reflector is disposed within a second well in the substrate.

10. The optical device as recited in claim 8, wherein a fourth of the plurality of waveguides has an associated fourth tap waveguide on the substrate to tap a portion of an optical signal propagating along the fourth waveguide as a fourth tap signal, the fourth tap waveguide terminating proximate a fourth out-of-plane reflector in the substrate that reflects the fourth tap signal received from the fourth tap waveguide out of the plane of the substrate, and a fourth detector element positioned to detect the reflected optical signal from the fourth out-of-plane reflector.

11. The optical device as recited in claim 1, wherein the first tap waveguide terminates with a focusing element proximate the first out-of-plane reflector for directing the first tap signal towards the first out-of-plane reflector.

12. The optical device as recited in claim 1, wherein the first out-of-plane reflector comprises a surface angled relative to a plane of the substrate, the surface being provided with a reflective coating to reflect the tapped optical signal.

13. The optical device as recited in claim 1, further comprising a multifiber connector arranged at the multifiber port of the substrate for coupling fibers of a multifiber cable to respective waveguides of the plurality of waveguides.

14. The optical device as recited in claim 1, wherein the first out-of-plane reflector comprises a front surface reflector.

15. The optical device as recited in claim 1, wherein the first out-of-plane reflector comprises a total internal reflector.

16. The optical device as recited in claim 1, wherein each of the plurality of fiber ports has an associated fiber count of one.

17. The optical device as recited in claim 1, wherein a first of the plurality of fiber ports has an associated second fiber count and a second of the plurality of fiber ports has an associated third fiber count, the second fiber count being different from the third fiber count.

18. The optical device as recited in claim 1, further comprising a lens disposed between the first out-of-plane reflector and the first detector element.

19. The optical device as recited in claim 1, wherein the first out-of-plane reflector comprises a curved reflecting surface to focus the first tap signal towards the first detector element.

20. The optical device as recited in claim 1, further comprising a first multifiber cable coupled to the multifiber port, fibers of the multifiber cable coupling to respective waveguides of the plurality of waveguides.

21. The optical device as recited in claim 20, further comprising fiber cables coupled to respective fiber ports of the plurality of fiber ports.

22. The optical device as recited in claim 20, wherein at least one of the fiber cables includes a fiber coupled to the substrate via a connector body connected to the substrate.

23. The optical device as recited in claim 20, wherein at least one of the fiber cables includes a fiber coupled to the substrate in a groove at the substrate edge.