Optical power monitoring with robotically moved macro-bending

A method may include bending a first optical fiber of a plurality of optical fibers; measuring light leaked from the first optical fiber with a photo detector; robotically moving the photo detector to a second optical fiber of the plurality of optical fibers; bending the second optical fiber; and measuring light leaked from the second other optical fiber with the photo detector.

BACKGROUND INFORMATION

Fiber-optic cables are becoming increasingly prevalent as digital communications expand. Fiber-optic cables may include transoceanic cables that carry international telephone calls and Internet traffic. Fiber-optic cables may also include cables to consumer homes that deliver broad-band internet, television, and/or telephone services.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1is a block diagram of an exemplary environment100for monitoring optical fibers. Exemplary environment100may include a fiber cable102, an optical fiber monitor104(“monitor104”), network devices106-1through106-N (collectively “network devices106,” individually “network device106-x”), and a control device108. In practice, there may be more, different, or fewer devices or a different arrangement of devices than what is shown inFIG. 1. Further, whileFIG. 1shows cable102, monitor104, and network devices106in environment100, one or more of these devices may be remotely located, e.g., the devices may be geographically diverse.

Fiber cable102may include a group of optical fibers112-1through112-N (collectively “fibers112,” individually “fiber112-x”) that couple cable102with monitor104. Network devices106-1through106-N may be coupled to monitor104through optical fibers110-1through110-N (collectively “fibers110,” individually “fiber110-x”), respectively. Control device108may be coupled to monitor104directly or through one or more networks.

Fiber cable102may be any type of fiber-optic cable. For example, fiber cable102may be a trans-oceanic or transcontinental communications cable. Fiber cable102may be a cable entering a person's house. Fiber cable102may be a cable entering a telecommunication company's central office. Fiber cable102may include one or more optical fibers, such as fibers112.

Monitor104may couple fibers112-1through112-N to fibers110-1through100-N, respectively, and may monitor signals passing from fibers110to fibers112or vice versa. In other words, monitor104may sit between cable102and network devices106to monitor the signals passing between them in one or both directions. Monitor104may measure properties of light received from optical fibers112or optical fibers110. For example, monitor104may measure the optical power to determine that one or more of fibers110or112is broken or not passing a strong signal.

Network devices106may include routers, switches, or computers, for example. Network devices106may include any device capable of receiving and/or transmitting communication signals, such as communication signals carried over fibers110.

Control device108may include a computer that sends or receives signals to or from monitor104. Control device108may receive signals from monitor104, such as signals reporting the status of optical fibers112and/or optical fibers110. Control device108may also send signals to monitor104to calibrate monitor104.

FIG. 2is a block diagram of exemplary components of control device108. Control device108may include a bus210, processing logic220, an input device230, an output device240, a communication interface250, and a memory260. Control device108may include other components (not shown) that aid in receiving, transmitting, and/or processing data. Moreover, other configurations of components in control device108are possible. Further, one or more components of control device108may be remotely located.

Bus210may include a path that permits communication among the components of control device108. Processing logic220may include any type of processor or microprocessor (or groups of processors or microprocessors) that interprets and executes instructions. In other embodiments, processing logic220may include an application-specific integrated circuit (“ASIC”), a field-programmable gate array (“FPGA”), or the like.

Communication interface250may include any transceiver-like mechanism that enables control device108to communicate with other devices and/or systems. Memory260may include a random access memory (“RAM”) or another type of dynamic storage device that may store information and instructions for execution by processing logic220; a read-only memory (“ROM”) device or another type of static storage device that may store static information and instructions for use by processing logic220; and/or some other type of magnetic or optical recording medium and its corresponding drive for storing information and/or instructions. Memory260may store a control application265, for example. Control application265may allow control device108to control monitor104to determine the status of fibers, such as fibers112or fibers110. Control application265may calibrate monitor104. Applications other than a control application265are possible.

Input device250may include a device that permits a user to input information into control device108, such as a keyboard, a keypad, a mouse, a pen, a microphone, one or more biometric mechanisms, or the like. Output device240may include a device that outputs information to the user, such as a display, a printer, a speaker, etc.

Control device108may perform certain operations, as described in detail below. Control device108may perform these operations in response to processing logic220executing software instructions contained in a computer-readable medium, such as memory260. A computer-readable medium may be defined as a physical or logical memory device and/or carrier wave. The software instructions may be read into memory260from another computer-readable medium or from another device via communication interface250. The software instructions contained in memory260may cause processing logic220to perform processes that are described below.

FIG. 3is a block diagram of an exemplary optical fiber monitor104. Monitor104may include a first group of fiber connectors302-11through302-1N and a second group of fiber optic connectors302-21through302-2N (collectively “connectors302,” individually “connector302-x”), a first fiber fixture304-1and a second fiber fixture304-2(collectively “fixtures304,” individually “fixture304-x”), a first group of fiber tension devices306-11through306-1N and a second group of fiber tension devices306-21through306-2N (collectively “tension devices306,” individually “tension device306-x”), a fiber rail308(“rail308”), a photo-detector head310(“head310”), and a group of optical fibers312-1through312-N (collectively “fibers312,” individually “fibers312-x”).

Fiber fixtures304may secure fibers312to limit motion of fibers312within monitor104. Fiber tension devices306may control the tension of fibers312between fiber fixtures304. For example, fiber fixture306-12and fiber fixture306-22may control the tension of fiber312-2between fixture304-1and fixture304-2. Fiber rail308may hold fibers312for measurement by head310.

FIG. 4Bis a block diagram of a cross-sectional view of exemplary fiber fixture304-xto secure fibers312. The cross-sectional view inFIG. 4Bis defined by the arrow labeled A inFIG. 4A.FIG. 4Bdepicts fiber312-2bound to fixture rail402with glue spot404-2. All fibers312may be similarly attached to rail402.

FIG. 5Ais a block diagram of fiber tension device306-xand a portion of fiber fixture304-x. The portion of fiber fixture304-xmay include fiber fixture rail402and glue spot404-x. Optical fiber312-xmay pass over fiber rail402under glue spot404-xand through fiber tension device306-x.

FIGS. 5B and 5Care block diagrams of exemplary internal components of fiber tension device306-x. Fiber tension device306-xmay include a first spring502-1and a second spring502-2(collectively “springs502”), a dynamic fiber holder504, and a glue spot506. Springs502may attach to fixture rail402on one end and may attach to dynamic fiber holder504on the other end. Glue spot506may hold optical fiber312-xto dynamic fiber holder504similarly to how glue spot404-xmay hold fiber312-xto fiber fixture rail402, as described inFIG. 4B. As shown inFIG. 5B, springs502may apply a force512on dynamic fiber holder504in the direction of fixture rail402. As shown inFIG. 5B, optic cable312-xmay have slack, as shown at portion508. Further, as shown inFIG. 5B, fiber312-xmay be pulled taught at portion510, e.g., fiber312-xmay be “straight” at portion510.

As shown inFIG. 5C, a force514in the direction away from fixture rail402may move dynamic fiber holder504and may stretch springs502. When springs502are stretched, optical fiber312-xmay become taught, e.g., straight, at portion516. Force514may result, for example, when optical fiber312-x(attached to dynamic fixture504) is pulled at portion510away from fiber fixture rail402. When force514is removed, springs502may return to the position as shown inFIG. 5Band fiber312-xmay once again have slack at portion508and be taught at portion510.

FIG. 6Ais a block diagram of rail308, optical fibers312, and photo-detector head310. In the exemplary embodiment ofFIG. 6A, optical fibers312may be above rail308and photo-detector head310may be placed above fibers312such that one of fibers312passes between rail308and head310.

FIG. 6Bis a block diagram of a cross section of an exemplary photo-detector head310and rail308. The cross-sectional view inFIG. 6Bis defined by the arrow labeled B inFIG. 6A. Head310may include a first photo detector602-1and a second photo detector602-2(collectively “photo detectors602”) and a control unit604.

Head310may include a concave portion608. Rail308may include a convex portion610that matches concave portion608. As shown inFIG. 6B, there may be a gap612between head310and rail308for passage of fiber312-2. In the exemplary embodiment, fiber312-2may be taught, e.g., straight, in gap612because of a force614and a force616exerted on fiber312-2. Force614and force616may be applied, for example, by tension device306-21and306-22as discussed above with respect toFIGS. 5B and 5C, e.g., forces614and616may correspond to force512inFIG. 5B. In other words, tension devices306may provide tension for fiber312-2. Fiber312-2may rest at the zenith of convex portion610.

As shown inFIG. 6C, head310and/or rail308may be moved so as to reduce gap612and bend fiber312-2. When fiber312-2is bent, a percentage of light may “leak” out of fiber312-2, a technique known as “macro-bending.” In the exemplary embodiment ofFIG. 6C, gap612has been reduced to the width of optic cable312-2as shown at portion618. Concave portion608and convex portion610may be formed as to assist macro-bending and the leakage of light. Photo detectors602may detect the light leaking from fiber312-2. Photo-detector602-1may detect light leakage in one direction and photo-detector602-2may detect light leakage in the opposite direction. The bending of fiber312-2may not physically harm fiber312-2so that fiber312-2may return to the shape shown inFIG. 6Bwithout damage. The shapes of rail308and head310may generate macro-bending on fiber312without damaging fibers312. Photo-detectors602may be shaped to conform to concave portion608.

When head310and/or rail308are moved to reduce gap612, they may exert a force620and a force622on fiber312-2. Forces620and622may pull on tension device306-12and tension device306-22, for example, as discussed above with respect toFIG. 5C. Forces620and622may correspond to force514inFIG. 5C. In other words, tension devices306may provide the slack for fiber312-2to bend during macro-bending. In one embodiment, there may be grooves (not shown) on rail308or on head310to maintain fiber312-xin a known position during measurement.

Control unit604may include a motor that may move head310along a path from one fiber312-xto another fiber312-x. For example,FIG. 7Ais a block diagram of monitor104with head310above optic cable312-2.FIG. 7Bis a block diagram of monitor104with head310above optic cable312-3. Head310may be moved to any one of fibers312, for example. In addition, the motor in control unit604may also move head310in relation to rail308to reduce gap612and to bend fibers312. When the motor in control unit604moves head310, such movement may be considered “robotically moving,” e.g., movement other than with a human hand.

FIG. 8is a diagram of exemplary optical fiber312-x. Optical fiber312-xmay include a jacket802and a transmission medium804. Jacket802may be formed from a material that can withstand multiple macro-bending events without damage. Jacket802may have a thickness to facilitate accurate positioning of optic cable312-xwith respect to head310and rail308for accurate measurement of leaked light. Jacket802may be highly transparent to the wavelengths of light used in transmission medium804for communications. High transparency of jacket802may result in a greater percentage of leaked light reaching photo-detectors602. Thus, a high transparency jacket802may allow for less light leakage from macro-bending in order to obtain an accurate measurement.

FIG. 9is a block diagram of exemplary components of control unit604. Control unit604may include a bus910, processing logic920, a motor930, a communication interface950, and a memory960. Control unit604may include other components (not shown) that aid in receiving, transmitting, and/or processing data. Moreover, other configurations of components in control unit604are possible. For example, one or more components of control unit604may be remotely located.

Bus910may include a path that permits communication among the components of control unit604. Processing logic920may include any type of processor or microprocessor (or groups of processors or microprocessors) that interprets and executes instructions. In other embodiments, processing logic920may include an ASIC, FPGA, or the like.

Communication interface950may include any transceiver-like mechanism that enables control unit604to communicate with other devices and/or systems. Memory960may include a RAM or another type of dynamic storage device that may store information and instructions for execution by processing logic920; a ROM or another type of static storage device that may store static information and instructions for use by processing logic920; and/or some other type of magnetic or optical recording medium and its corresponding drive for storing information and/or instructions. Memory960may store a control application965, for example. Control application965may allow control device108to control monitor104in order to determine the status of fiber cables, such as fibers112or fibers110. Control application965may also calibrate monitor104. Applications other than a control application965are possible.

Motor930may include a rotor, a stator, a hub, and other components that may form a motor. Motor930may be a linear motor. Motor930may move head310along rail308such that photo detectors602may detect light leaked from fibers312. Motor930may also move head310and/or rail308to reduce gap612.

Control unit604may perform certain operations, as described in detail below. Control unit604may perform these operations in response to processing logic920executing software instructions contained in a computer-readable medium, such as memory960. The software instructions may be read into memory960from another computer-readable medium or from another device via communication interface950. The software instructions contained in memory960may cause processing logic920to perform processes that are described below.

FIG. 10is a flow chart of an exemplary process1000for monitoring optical fibers in an optical fiber monitor, such as monitor104. Process1000may begin by moving a photo-detector head to a first fiber for measuring leaked light (block1002). For example, head310may be moved over fiber312-2as shown inFIGS. 7A and 6B. The optical fiber may be bent, e.g., macro-bent, and light may be measured (block1004). For example, head310and rail308may reduce gap612between the two and may bend fiber312-2as shown inFIG. 6B, and photo-detectors602may measure light leaked from fiber312-2. The measured light may be reported and/or recorded or optical fiber monitoring device104may be calibrated (block1006). For example, control unit604may report the measured light to control device108. The power of the light leaked from optic cable312-2may be proportional to the total light power passing through optic cable312-2. Therefore, if the proportion of leaked power to total power, e.g., the percentage of leaked power, is known, it may be possible to determine (e.g., calculate) an unknown power of light passing through optic cable312-2by measuring the leaked power. The process of obtaining the relationship, e.g., the proportion, of leaked power to total power may be referred to as “calibration.” Monitor104may be calibrated by passing a known power of light through fibers312and measuring the leaked light with photo-detectors602, for example. The relationship may be determined between the known power of light passed through fibers312and the measured leaked light.

Calibration may take place on fibers312when fibers312are located in monitor104. Alternatively, calibration may take place on fibers312before fibers312are placed in monitor104during assembly of monitor104. Calibration may also take place on a fiber substantially similar to fibers312.

If there is another fiber to be measured (block1008:YES), the photo-detector head may be moved to the next fiber to measure and process1000may repeat. For example, control unit604may move head310to fiber312-2as shown inFIG. 7B. If there are no other fibers to measure (block1008:NO), process1000may end.

FIGS. 11A,11B, and11C are block diagrams of another exemplary optical fiber monitor104.FIG. 11Ais a block diagram of a rail308′, fibers312, and a photo-detector head310′ (“head310′”). In the exemplary embodiment ofFIG. 11A, fibers312may be placed above rail308′ and head310′ may be placed above a fiber (shown above fiber312-2inFIG. 11A).FIGS. 11B and 11Care block diagrams of the cross section of photo-detector head310′ and rail308′. The cross-sectional view is defined by the arrow labeled C inFIG. 11A. Head310′ may include a first photo detector1102-1and a second photo detector1102-2(collectively “photo detectors1102”) and a control unit604.

Head310′ may include a convex portion1108. Rail308′ may include a concave portion1110that matches convex portion1108. As shown inFIG. 11B, there may be a gap1112between head310′ and rail308′ for passage of fiber312-2. In the exemplary embodiment, fiber312-2may be taught, e.g., straight, in gap1112because of forces exerted by tension devices, such as tension device306-12and tension device306-22. Fiber312-2may rest at two points of contact on rail308′ toward the ends of concave portion1110.

As shown inFIG. 11C, head310′ and/or rail308′ may be moved so as to reduce gap1112and bend fiber312-2. As discussed above, when fiber312-2bends, light may leak out of fiber312-2. In the exemplary embodimentFIG. 11C, gap1112has been reduce to the width of optic cable312-2as shown at point1120.

Photo detectors1102may detect the light leaking from fiber312-2. Photo-detector1102-1may detect light leakage in one direction and photo-detector1102-2may detect light leakage in the opposite direction.

When head310′ and/or rail308′ are moved to reduce gap1112, a force may be exerted on fiber312-2, pulling on tension device306-12and tension device306-22. In one embodiment, there may be grooves (not shown) on rail308or on head310to maintain fiber312-xin a known position during measurement.

FIG. 12is a block diagram of an exemplary optical fiber monitor1204in one embodiment. Monitor1204may not include fiber connectors302as shown inFIG. 3. Integrated fiber monitor1204may include a first group of fiber pigtails1206-1and a second group of optical fiber pigtails1206-2(collectively “fiber pigtails1206”). Fiber pigtails1206may be spliced into other optical components, avoiding losses due to optical connectors, such as connectors302.

FIG. 13is a block diagram of an exemplary optical switch1300including integrated optical fiber monitor1204. Optical switch1300may also include an integrated optical switch1302coupled to integrated monitor1204, a first group of fiber connectors1304, and a second group of fiber connectors1306. Optical switch1300may switch inputs from optical connectors1304to outputs on connectors1306. Optical switch1300may also switch inputs from connectors1306to outputs on connectors1304. Optical switch1300may be coupled to control device108, for example. Control device108may calibrate integrated monitor1204, may receive status information regarding optical signals passing through integrated monitor1204, and may control integrated monitor1204.

FIGS. 14A and 14Bare block diagrams of an exemplary optical multiplexer1402and an exemplary optical demultiplexer1404, respectively, each including integrated fiber monitor1204. Multiplexer1402may also include an integrated optical multiplexer1406, a group of input optical fiber connectors1410, and an output fiber connector1412. Multiplexer1402may receive signals on connectors1410and may multiplex the signals for outputting on output connector1412. Optical multiplexer1402may be coupled to control device108. Control device108may calibrate integrated monitor1204, may receive status information regarding optical signals passing through integrated monitor1204, and may control integrated monitor1204.

In addition to integrated monitor1204, demultiplexer1404may include an integrated optical demultiplexer1408, a group of output optical fiber connectors1414, and an input fiber connector1416. Demultiplexer1402may receive a signal on fiber connector1416and may demultiplex the signal for outputting on connectors1414. Demultiplexer1404may be coupled to control device108. Control device108may calibrate integrated monitor1204, may receive status information regarding optical signals passing through integrated monitor1204, and may control integrated monitor1204.

FIG. 15is a block diagram of an exemplary optical power splitter1500including integrated fiber monitor1204. Optical power splitter1500may also include an integrated power splitter1502, an input fiber connector1504, and a group of output fiber connectors1506. Optical power splitter1500may receive an input signal on input power connector1504, may split the power, and may output a split power signal on connectors1506. Optical power splitter1500may be coupled to control device108. Control device108may calibrate integrated monitor1204, may receive status information regarding optical signals passing through integrated monitor1204, and may control integrated monitor1204.

FIG. 16is a block diagram of an exemplary add/drop module1600including an integrated fiber monitor1204. Add/drop module1600may also include integrated add/drop device1602, an input fiber connector1604, an output fiber connector1606, and a group of add/drop fiber connectors1608. Add/drop module1600may input signals from input fiber connector1604and may output signals on output fiber connector1606. Add/drop module1600may input signals from input fiber connector1604and may output, i.e., drop, signals on one or more of fiber connectors1608. Add/drop module1600may input signals from one or more of input fiber connector1608and may output, i.e., add, signals on output fiber connector1606. Add/drop module1600may be coupled to control device108, for example, for calibrating, instructing, and receiving data from add/drop module1600.

Embodiments disclosed herein may provide a long-term optical fiber degradation monitoring system. Embodiments described herein may allow for continuous monitoring of fiber-optic cables. Embodiments disclosed herein may provide remote monitoring without having to send working crews to remote locations.

Macro-bending may provide less power loss than using an optical tap, for example. Further, power loss when using macro-bending may be temporary, e.g., only when a fiber is being bent and measured.

Although cable102is shown inFIG. 1with an array of fibers112, cable102may include a single fiber and monitor104may include one set of fiber connectors302and one set of tension devices306.

Although rail308is shown inFIG. 3as one continuous component, rail308may include multiple shorter segments. Further, head310may also be considered a “rail” in the sense that head310may also help bend fibers312. In addition, althoughFIG. 3shows a pair of tension devices306for each fiber312-x, in another embodiment only one tension device306-xmay be used for each fiber312-x.

Although fixture rail402is shown inFIG. 4as one continuous component, fixture rail402may include multiple shorter segments. In addition, although fiber312-2is secured to fixture rail402using glue, any other method of securing fibers312to fixture rail402may be used.

AlthoughFIGS. 5B and 5Cshow two springs502in each tension device306-x, one or more than two springs are possible. In addition, springs502may be replaced with any device capable of exerting a force.

In one embodiment, there may be a group of photo-detector heads, e.g., a group of photo-detector heads510. In this embodiment, motor930may not have to move head510from one fiber to another fiber for measuring leaked light. In one embodiment, there may be as many photo-detector heads as fibers and motor930may be omitted. In one embodiment, only one photo detector head may be provided to measure the light in a group of optical fibers. In another embodiment, a group of photo detector heads may be provided to measure the light in the group of fibers. Embodiments disclosed herein may allow for monitoring of fiber cables while introducing only minor insertion loss during measurement. In one embodiment, a receiver may be provided to detect the signal in an optical fiber, e.g., to allow surveillance of communication in the optical fiber.

While a series of acts has been described above with respect toFIG. 10, the order of the acts may differ in other implementations. Moreover, non-dependent acts may be performed in parallel.

It will be apparent that aspects of the embodiments, as described above, may be implemented in many different forms of software, firmware, and hardware in the implementations illustrated in the figures. The actual software code or specialized control hardware used to implement these embodiments is not limiting of the invention. Thus, the operation and behavior of the embodiments of the invention were described without reference to the specific software code—it being understood that software and control hardware may be designed to implement the embodiments based on the description herein.

Further, certain portions of the invention may be implemented as “logic” that performs one or more functions. This logic may include hardware, such as an application specific integrated circuit, a field programmable gate array, a processor, or a microprocessor, software, or a combination of hardware and software.