FIBRE FIBER CABLE AND SYSTEM AND METHOD FOR DISTRIBUTION OF ULTRA-HIGH POWER USING FIBRE FIBER CABLE - Patent application

Abstract

Embodiments include a fiber optic cable comprising a length extending between a first end and a second end, a central cooling tube, a plurality of optical fibers disposed radially around the cooling tube, each optical fiber including a fiber core and a cladding disposed around the fiber core, an outer protective cover, and an inner thermal filler disposed between the outer protective cover and the central cooling tube and surrounding each of the optical fibers, the central cooling tube, the outer protective cover, the inner thermal filler, and the plurality of optical fibers each extending the length of the cable.Various systems and methods for removing defects from individual optical fibers and distributing power over long distances using fiber optic cables are also provided.

Description

[Technical field]

[0001] The present disclosure relates generally to optical fibers, and more particularly to fiber optic cables, systems that use or otherwise distribute electrical power using fiber optic cables, and techniques for refining the optical fibers contained in such cables. [Background technology]

[0002] Fiber optic cables can be used to transmit power from a power source to an endpoint that is far removed. The term "power over fiber" typically refers to a system in which electrical power generated by a power source is converted to optical power using a laser source, and the optical power is transmitted through a fiber optic cable to a photodetector, which converts the optical power back into electrical power to supply an electrical load. As an example, a typical fiber optic power system includes a laser diode, a multimode optical fiber made of silica fiber, and a photovoltaic cell or other semiconductor device constructed of materials such as gallium arsenide (GaAs), indium phosphide (InP), or indium gallium arsenide (InGaAs).

[0003] Fiber optic power systems offer several advantages over typical electrical power systems, including, for example, little or no risk of electrical interference, lightning-induced outages, and explosions caused by electrical sparks. Fiber optic cables also have significantly higher power densities, can withstand higher temperatures, and are much lighter than electrical cables. Furthermore, unlike electrical wires, the same optical fiber can be used to transmit optical power in one direction and data back in the other direction, for example using a different wavelength or channel. Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional optical fiber power systems utilizing silica-based fibers suffer from transmission and distribution losses, conversion efficiencies at both the transmitting (i.e., electrical to optical) and receiving (i.e., optical to electrical) sides, and a large amount of attenuation in the transmission medium itself, thus limiting the wide applicability of such systems. For example, transmission of high power over long distances (e.g., 800 kilometers (km) above sea level or 50 km below sea level) is achieved using high-voltage direct current (HVDC) transmission systems (also known as power or electrical superhighways), which use copper or aluminum cables instead of silica-based fibers. Nevertheless, conversion efficiencies from alternating current (AC) to HVDC are believed to be as low as 60%, and some existing submarine systems suffer from total power losses of 65% or more.

[0005] Another known type of fiber is zirconium fluoride-barium fluoride-lanthanum fluoride-aluminum fluoride-sodium fluoride (ZrF4-BaF2-LaF3-AlF3-NaF), also known as "ZBLAN" fiber. ZBLAN is a type of fluoride glass that has better infrared transmission and a significantly lower loss profile than standard silica. For example, as shown in FIG. 1, standard silica fiber has a minimum loss of about 0.25 dB / km at 1550 nanometers (nm), while ZBLAN fiber has a theoretical loss limit of about 0.0001 dB / km, three orders of magnitude lower. However, this loss limit is often difficult to reach because ZBLAN contains undesirable impurities or crystallites that can form during the manufacturing process and inhibit the material's transmittance.

[0006] Specifically, as shown in FIG. 2, ZBLAN has a temperature at which the ZBLAN fiber transitions from a solid glass to a liquid or viscous state (i.e., the glass transition temperature T g ) and the temperature at which crystallization occurs (crystallization temperature T x) is relatively small. This results in a narrow operating range for ZBLAN, and therefore crystallites are relatively easily generated during the drawing process. It has been shown that by growing ZBLAN in zero or microgravity (i.e., in space) rather than unit gravity (i.e., on Earth), crystallites can be suppressed or reduced due to reduced convection processes during microgravity conditions. However, conventional techniques for producing ZBLAN in microgravity conditions are extremely costly, time consuming, and / or difficult to implement on a large scale, for example by requiring travel in space or the use of abandoned mine shafts on Earth.

[0007] Thus, there remains a need in the art for fiber optic cables and overall fiber optic power systems that can efficiently transmit ultra-high power over long distances with significantly lower losses.

[0008] The present invention addresses these and other problems with systems, methods and apparatus configured to provide: (1) an optical fiber cable including a plurality of individual ZBLAN fibers capable of transmitting very high power laser energy over long distances with significantly less loss; (2) a technique for removing defects from the optical fiber including annealing the fiber in a microgravity environment created on Earth; and (3) an optical fiber power delivery system including the optical fiber cable, a very high power laser source coupled to a first end of the optical fiber cable, and a photodiode detector coupled to a second end of the optical fiber cable. [Means for solving the problem]

[0009] One exemplary embodiment is a system for removing defects in a length of optical fiber, including a fiber core and a cladding surrounding the fiber core, comprising: x ) higher than the fiber melting temperature (T mThe annealing unit includes a heating chamber configured to internally heat the optical fiber segment to a first temperature lower than a crystallization temperature (T) of the optical fiber, and the heating chamber is configured to move the annealing unit from a high elevation to a low elevation using a free fall motion and is further configured to maintain the first temperature of the segment of optical fiber during a first period of the free fall motion, and the annealing unit heats the optical fiber segment to a crystallization temperature (T) of the optical fiber during a second period of time. x ) lower than the glass transition temperature (T g ) at a critical cooling rate associated with the optical fiber, and after completion of the second period, the annealing unit is further configured to transition a subsequent segment of the optical fiber into a heating chamber, the chamber being further configured to move the annealing unit from a low elevation to a high elevation.

[0010] Another exemplary embodiment is a method for removing defects from a length of optical fiber, the length including a fiber core and a cladding surrounding the fiber core, that is disposed at least partially within an annealing unit of a system including one or more processors, the method comprising the steps of: (a) using the one or more processors to place a given segment of the optical fiber within a heating chamber of the annealing unit; and (b) using the heating chamber and the one or more processors to heat the given segment to a crystallization temperature (T x ) higher than the fiber melting temperature (T m (c) using one or more processors to move the annealing unit from a higher elevation to a lower elevation using a free fall motion; (d) during the free fall motion, using a heating chamber and one or more processors to maintain the given segment at the first temperature for a first period of time; and (e) during a second period of time, using one or more processors to maintain the given segment at the first temperature above the fiber crystallization temperature (T x ) lower than the glass transition temperature (T g) at a critical cooling rate of the fiber; (f) after the second period of time, moving the annealing unit from a lower elevation to a higher elevation using one or more processors; and (g) repeating steps (a)-(f) using one or more processors for each subsequent segment of optical fiber until the entire length of the optical fiber has been processed.

[0011] Yet another exemplary embodiment is a system for reducing defects in a length of optical fiber including a fiber core and a cladding surrounding the fiber core, comprising: x ) higher than the fiber melting temperature (T m The optical fiber includes an annealing unit including a heating element configured to selectively heat the optical fiber to a first temperature below a crystallization temperature of the fiber and a clamping system configured to selectively secure the given segment adjacent to the heating element; and an acceleration chamber configured to house the annealing unit and move the annealing unit and the given segment of the optical fiber secured within the annealing unit from a first position to a second position at a first acceleration and to move the annealing unit and the given segment from the second position to the first position at a second acceleration lower than the first acceleration, wherein the given segment of the optical fiber is heated by the heating element to the first temperature for a first period of time while at the first acceleration, and the given segment cools to a glass transition temperature (T) below a crystallization temperature of the fiber at a critical cooling rate associated with the fiber for a second period of time. g ), and the clamping system is configured to release the given segment of the optical fiber after the second period of time and secure a subsequent segment of the optical fiber adjacent to the heating element.

[0012] Another exemplary embodiment is a method for removing defects from a length of optical fiber, the length including a fiber core and a cladding surrounding the fiber core, that is disposed at least partially within an annealing unit of a system including one or more processors, the method comprising the steps of: (a) using one or more processors to clamp a given segment of the optical fiber adjacent to a heating element of the annealing unit; and (b) using the one or more processors and the heating element to heat the given segment to a crystallization temperature (T x ) higher than the fiber melting temperature (T m (c) moving, using one or more processors, the annealing unit from the first position to a second position at a first acceleration; (d) maintaining, during the first acceleration, the first temperature of the given segment for a first period of time using one or more processors and a heating element; and (e) during a second period of time, using one or more processors to heat the given segment to a glass transition temperature (T) below the crystallization temperature of the fiber. g (f) releasing the given fiber segment after a second period of time using one or more processors; (g) moving the annealing unit from the second position to the first position at a second acceleration rate slower than the first acceleration using one or more processors; and (h) repeating steps (a)-(g) using one or more processors for each subsequent segment of optical fiber until the entire length of the optical fiber has been processed.

[0013] Yet another exemplary embodiment provides a fiber optic power system comprising a laser light source configured to emit high power laser energy, a photodetector configured to convert the detected light into electrical energy, and a fiber optic cable, the fiber optic cable including a first end coupled to the laser light source and an opposite second end coupled to the photodetector, a length extending between the first and second ends, and a plurality of optical fibers each extending the length of the cable and having a thermal filler surrounding the fiber.

[0014] Another exemplary embodiment provides a method of managing power supply in a fiber optic power system including a transmitting unit having a laser light source, a receiving unit having a photodetector, and a fiber optic cable coupled between the transmitting unit and the receiving unit, the fiber optic cable including a plurality of optical fibers, each optical fiber extending the length of the fiber optic cable, the method including the steps of: transmitting high power laser energy from the transmitting unit to the receiving unit using a certain number of optical fibers included in the fiber optic cable; receiving at a processor a data signal including information regarding a power requirement of an electrical load coupled to the receiving unit, the data signal being transmitted from the receiving unit to the transmitting unit using the fiber optic cable; and controlling, using the processor, the high power laser energy output by the transmitting unit by adjusting the number of optical fibers used to transmit the laser energy based on the power requirement of the electrical load.

[0015] Yet another exemplary embodiment provides an optical fiber cable comprising a length extending between a first end and a second end, a central cooling tube, a plurality of optical fibers arranged radially around the cooling tube, each of the optical fibers including a fiber core and a cladding arranged around the fiber core, an outer protective cover, and an inner thermal filler disposed between the outer protective cover and the central cooling tube and surrounding each of the optical fibers, wherein the central cooling tube, the outer protective cover, the inner thermal filler, and the plurality of optical fibers each extend the length of the cable.

[0016] As should be understood, the present disclosure is defined by the appended claims. This specification is a summary of aspects of the embodiments and should not be used to limit the scope of the claims. As will be apparent to those skilled in the art upon review of the following figures and detailed description, other implementations are contemplated according to the technology described herein, and such implementations are also intended to be included within the scope of this application.

[0017] For a better understanding of the present invention, reference may be made to the embodiments illustrated in the following drawings. To highlight and clearly show the novel features described herein, the components in the drawings are not necessarily to scale, may omit relevant elements, or in some cases may be exaggerated in proportion. Also, as is known in the art, system components may be arranged in a variety of configurations. Additionally, in the drawings, like reference numerals designate corresponding parts throughout the several views. [Brief description of the drawings]

[0018] [Figure 1] 1 is a graph showing the known predicted loss profiles of silica and ZBLAN. [Diagram 2] 1 is a graph showing known differential scanning calorimeter (DSC) results showing the crystallization temperature and glass transition temperature of ZBLAN. [Diagram 3] FIG. 4 is a functional block diagram illustrating an example fiber optic power system including the fiber optic cable of FIG. 3, in accordance with some embodiments. [Figure 4] FIG. 1 is a schematic diagram illustrating a cross-sectional view of an exemplary fiber optic cable according to some embodiments. [Diagram 5] 1 is a graph illustrating an acceleration profile used to improve an optical fiber, according to some embodiments. [Figure 6] 1 is a flow diagram of an exemplary method for removing a defect from a length of optical fiber, according to some embodiments. [Figure 7A] 7 is a functional block diagram of an exemplary improvement system for reducing defects in an optical fiber using the method of FIG. 6, according to some embodiments. [Figure 7B] FIG. 7B is a functional block diagram of an exemplary annealing unit included in the improved system of FIG. 7A, according to some embodiments. [Figure 8] 4 is a flow diagram of another exemplary method for removing a defect from a length of optical fiber, according to some embodiments. [Figure 9] 9 is a schematic diagram of an exemplary retrofit system for removing defects in an optical fiber using the method of FIG. 8, according to some embodiments. [Figure 10A] FIG. 10 is a schematic diagram illustrating a front perspective view of an exemplary annealing unit included in the improved system of FIG. 9, according to some embodiments. [Figure 10B] FIG. 10 is a schematic diagram illustrating a bottom perspective view of an exemplary annealing unit included in the improved system of FIG. 9, according to some embodiments. [Figure 10C] FIG. 10 is a schematic diagram illustrating a top view of an exemplary annealing unit included in the improved system of FIG. 9, according to some embodiments. [Figure 11A] 10 is a schematic diagram of an exemplary clamping system for securing an optical fiber in the improved system of FIG. 9, according to some embodiments. [Figure 11B] 10 is a schematic diagram of an exemplary clamping system for securing an optical fiber in the improved system of FIG. 9, according to some embodiments. [Figure 12] FIG. 2 is a functional block diagram of another example fiber optic power system in accordance with some embodiments. [Figure 13] FIG. 1 is a functional block diagram of an exemplary optical power distribution system in accordance with some embodiments. [Figure 14] 1 is a flow diagram of an exemplary method for managing power transmission in a fiber optic power supply system, according to some embodiments. [Figure 15]FIG. 2 is a functional block diagram of another example fiber optic power system configured for medical applications, according to some embodiments. [Figure 16] 16 is a schematic diagram illustrating a cross-sectional view of an exemplary optical fiber included in the system of FIG. 15 in accordance with some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] While the invention can be embodied in various forms, certain illustrative, non-limiting embodiments are shown in the drawings and will be described below, with the understanding that the present disclosure should be considered as an exemplification of the invention and is not intended to limit the invention to the specific embodiments shown.

[0020] In this application, the use of disjunctives is intended to include conjunctions. The use of definite and indefinite articles is not intended to indicate cardinality of the number of elements. In particular, reference to an object followed by "the" or "a" or "an" is intended to indicate one of a possible plurality of such objects.

[0021] In the following description, elements, circuits, and functions may be shown in block diagram form to avoid obscuring the disclosure in unnecessary detail. Additionally, the block designations and division of logic between various blocks are illustrative of specific embodiments. Additionally, those skilled in the art will appreciate that the information and signals shown in the block diagrams may be represented using a variety of different technologies or techniques. For example, the figures may represent data, instructions, signals, or commands, which will be understood to represent voltages, currents, electromagnetic waves, magnetic fields, or light fields, or combinations thereof. Additionally, while some figures may represent a signal as a single signal for clarity of illustration, those skilled in the art will recognize that the signal may also represent a bus of multiple signals. Various exemplary logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed using one or more processors. As will be appreciated by those skilled in the art, the disclosure of separate processors in the block diagrams may represent multiple processors performing the functions or logical sequences disclosed herein, or may represent multiple functions or sequences performed on a single processor.

[0022] The systems, methods and apparatus described herein provide techniques for improving ZBLAN fiber and provide a fiber optic cable constructed from multiple strands of modified ZBLAN fiber capable of transmitting large amounts of power over very long distances with significantly lower losses, as well as a fiber optic power delivery system that utilizes the fiber optic cable as the transmission medium between a light source contained in an electrical-to-optical conversion unit and a photodetector contained in an optical-to-electrical conversion unit.

[0023] Various applications of the optical fiber power supply system are envisioned, including optical power distribution systems and medical or surgical applications. Embodiments include an optical power distribution system that uses optical fiber cables as interconnectors for intercontinental transmission of ultra-large amounts of optical power (e.g., enough to power a small country) under seabed or subsea conditions. For example, the optical power distribution system can distribute up to 1 gigawatt of power over distances as much as 1000 km at sea level, or as much as 50 km under the sea. Other embodiments provide optical power distribution systems that use optical fiber cables to distribute power over a power grid between power distribution stations, and / or to power towers in residential and commercial environments in power over ethernet (POE) applications, and / or to distribute power in various automotive and aerospace applications.

[0024] 3 illustrates an exemplary fiber optic power system 100 including a light source 102, a fiber optic cable 104, and a photodetector 106, according to an embodiment. As illustrated, the fiber optic cable 104 includes a first end 108 coupled to the light source 102, an opposite second end 110 coupled to the photodetector 106, and a length x extending between the first and second ends. In an embodiment, each of the light source 102, the fiber optic cable 104, and the photodetector 106 can be optimally configured to maximize conversion efficiency, maximize power transmission distance, and minimize insertion loss. The fiber optic power system 100 can be used in a variety of applications requiring the transmission of optical power between two points, such as, for example, power distribution systems for commercial, residential, or other applications (e.g., as shown in FIG. 13), and surgical devices (e.g., as shown in FIG. 15).

[0025] The light source 102 includes one or more laser diodes or other semiconductor devices capable of converting electrical energy to optical energy and emitting the optical energy. In some embodiments, the light source 102 is part of a large-scale electrical-to-optical conversion unit, such as that shown in FIG. 12. In a preferred embodiment, the light source 102 is a highly efficient laser source capable of emitting very high power laser energy at a very low threshold current. As an example, the light source 102 (also referred to herein as a "laser source") can include one or more high power laser diode bars (e.g., GaInAsSb / AlGaAsSb diodes) operating at a wavelength of about 2.1 microns (μm). As another example, the laser diodes in the light source 102 can be multi-emitter multi-mode laser diodes or any other suitable laser diodes having a wavelength of about 980 nanometers (nm) and an output power of about 420 watts (W). In one embodiment, the light source 102 has a conversion efficiency of at least about 85 percent and a peak power delivery per link of at least about 1 gigawatt (GW). In some embodiments, the light source 702 includes multiple laser diodes arranged in an array (e.g., a diode array). In such cases, each diode can be individually controlled (e.g., turned on or off) to vary or control the total output power of the light source 102. The light source 102 can further include one or more monitor diodes configured to stabilize the output of the light source 102 (e.g., prevent fluctuations in laser energy). In some embodiments, the monitor diodes of the light source 102 are further configured to monitor signals (e.g., optical data signals) received from the photodetector 106 at the light source 102 and provide these signals to a processor (e.g., processor 730 of FIG. 7).

[0026] The photodetector 106 includes a photodiode, photovoltaic cell, or other semiconductor device capable of detecting laser light or other optical energy and converting the detected light into electrical energy. In some embodiments, the photodetector 106 is part of a larger scale optical-to-electrical conversion unit, such as that shown in FIG. 12. In a preferred embodiment, the photodetector 106 includes one or more high efficiency photodiode detectors (e.g., four-junction InGaAs). In one embodiment, the photodetector 106 has a conversion efficiency of at least about 85 percent and a peak power supply per link of at least about 1 gigawatt (GW), and a continuous power transmission of about 1 Watt (W).

[0027] The fiber optic cable 104 can act as a transmission medium to carry optical power from the light source 102 to the photodetector 106. The fiber optic cable 104 can also be configured to carry data signals in addition to optical power, for example as shown in FIG. 13. In a preferred embodiment, the fiber optic cable 104 is an ultra-high power cable that includes multiple optical fibers bundled together with a cooled center and a thermal acrylic filler that runs the length of the cable and surrounds each optical fiber and includes ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN). In one embodiment, the fiber optic cable 104 can transmit laser energy having a power of at least about 1 gigawatt (GW) with a loss of about 0.1 decibels (dB) and a transmission loss of 0.4 GW / cm. 2 It can be transmitted over distances of at least about 1000 kilometers (km) with a power density of

[0028] 4 illustrates a cross-sectional view of an exemplary fiber optic cable 200, according to an embodiment. Fiber optic cable 200 may be included in fiber optic power system 100 or in any of the other systems described herein as fiber optic cable 104. In other embodiments, fiber optic cable 200 may be configured to transmit communication signals over long distances instead of optical power.

[0029] As shown, the fiber optic cable 200 includes a plurality of optical fibers 202 radially disposed around a central cooling tube 204 and encased by an outer protective cover 206. According to some embodiments, the fiber optic cable 200 may include any number of fibers 202 selected from a range of about 5-10 fibers depending on the desired power capacity and transmission distance. In one such embodiment, the fiber optic cable 200 includes a bundle of eight optical fibers 202 and transmits laser energy having at least about 1 gigawatt (GW) of power with a loss of about 0.1 decibels (dB) and a transmission loss of 0.4 GW / cm. 2 over a distance of at least about 1000 kilometers (km) at a power density of 1000 .mu.m. In another embodiment, the fiber optic cable 200 includes up to about 8000 optical fibers 202 to accommodate ultra-high capacity power transmission needs.

[0030] By bundling multiple fibers 202 into a single fiber optic cable 200, the cable 200 can be used to vary the power delivery to an endpoint or electrical load coupled thereto by simply controlling the number of fibers 202 used for power transmission. In this manner, the transmitted optical power can be temporarily tailored to the distribution needs of the electrical load.

[0031] The cooling tubes 204 are configured to neutralize or dissipate heat generated by the optical fiber 202 during power transmission, thereby enhancing the power capacity of the cable 200. For example, the cooling tubes 204 may be configured to keep the temperature of the cable 200 below the thermal expansion temperature of the ZBLAN fiber and well below the glass transition temperature of ZBLAN (e.g., about 315 degrees Celsius (°C)). In one example embodiment, the cooling tubes 204 are configured to hold or maintain the overall temperature of the cable 200 below 100°C. In other embodiments, the cooling tubes 204 may be configured to maintain the cable temperature at or below a different threshold temperature.

[0032] According to an embodiment, the cooling tube 204 includes a hollow interior filled with a suitable cooling substance or coolant 208, such as air or other gas, or a suitable oil or other liquid. For example, the coolant 208 can include a mineral oil or an alkylate, such as linear decylbenzene or branched nonylbenzene. In some embodiments, the coolant 208 is cold air, and the two ends of the cooling tube 204 (e.g., at either end of the cable 200) can be kept open to allow the cold air to passively permeate the tube 204. In other embodiments, the coolant 208 is cold air or liquid that is actively forced throughout the tube 204 using a coolant management pump (not shown) located at one or more ends of the cable 200 (e.g., in a connector). In addition to having cooling properties, the substance 208 can also be configured to maintain the mechanical integrity of the tube 204 by maintaining a threshold amount of pressure within the cooling tube 204. The exact amount of pressure required may vary depending on the number of fibers 202 contained in cable 200, the type of coolant 208, and the environment in which cable 200 is used (eg, below sea level or underground).

[0033] The cooling tubes 204 themselves may be made of aluminum, acrylic, or other suitable materials. For example, if thicker walls and / or greater mechanical stability are required (e.g., if the cable 200 contains many fibers 202 and thus transmits a lot of power and generates a lot of heat), the cooling tubes 204 may be made of aluminum. As another example, if thinner walls are sufficient (e.g., if the cable 200 contains few fibers 202 and thus transmits less power and generates less heat), the cooling tubes 204 may be made of acrylic. In embodiments in which the cable 200 transmits a small amount of power, the cooling tubes 204 may be made very small in diameter or even eliminated entirely.

[0034] The outer protective covering 206 (also referred to as a "protective jacket") is constructed of polyurethane (PUR) or polyvinyl chloride (PVC) and is configured to protect and insulate the fibers 202 and cooling tubes 204 from external physical forces and chemical degradation. The protective covering 206 also provides a housing that encases the internal components of the cable 200. In some embodiments, the outer protective covering 206 includes multiple layers of material that are concentrically arranged and bonded together to form the covering 206.

[0035] As shown in FIG. 4, the fiber optic cable 200 further includes an inner thermal filler 210 disposed between the outer protective cover 206 and the central cooling tube 204 and surrounding each of the optical fibers 202. In an embodiment, the thermal filler 210 is configured to maintain the spatial or mechanical integrity of the cable 200 and to maintain a consistent temperature throughout the cable 200. For example, the thermal filler 210 completely surrounds each of the optical fibers 202, thereby isolating or preventing contact between the individual fibers 202 and thus avoiding the formation of hot spots when there is a heat buildup in one or more of the fibers 202. Furthermore, the thermal filler 210 can have a porous structure configured with multiple holes of different sizes to provide variable insulation and structural integrity. Airflow through these holes conducts or moves heat throughout the filler 210, thus reducing or preventing heat buildup around a particular fiber 202. According to an embodiment, the thermal filler 210 may be constructed of acrylic (eg, polymethylmethacrylate (PMMA)) or other suitable material.

[0036] The fiber optic cable 200 has a length (e.g., length x as shown in FIG. 3 ) extending between a first end and a second end, with the central cooling tube 204, the outer protective cover 206, the inner thermal filler 210, and each of the plurality of optical fibers 202 extending the length of the cable 200. As such, each of the optical fibers 202 may extend substantially parallel to the central cooling tube 204, and the outer protective cover 206 may be concentrically aligned with the cooling tube 204.

[0037] According to an embodiment, each optical fiber 202 is a multimode fiber having a fiber core 212 and a cladding 214 disposed about the fiber core 212. The fiber core 212 may be centrally disposed in the cladding 214 and fused or spliced ​​to the cladding 214. The core 212 may be a step index fiber core comprising ZBLAN fiber drawn in a microgravity environment and having a diameter selected to optimize power transmission along the length of the fiber 202. In some embodiments, the fiber core 212 has a diameter selected from the range of about 200 μm to about 400 μm. In other embodiments, the fiber core 212 has a diameter selected from the range of about 300 μm to about 500 μm. In one example embodiment, the core diameter is about 600 μm.

[0038] The cladding 214 may be configured to confine light within the fiber core 212 by inducing total internal reflection at the boundary between the cladding 214 and the core 212. In an embodiment, the cladding 214 may be formed of a fluoride glass material that is similar to, but optically distinct from, the ZBLAN fiber material. For example, the cladding 214 may be constructed of a material that has a lower refractive index than the refractive index of the fiber core 212. The thickness of the cladding 214 may be selected based on the core diameter, the overall diameter desired for the optical fiber 202, the optimal ratio between these two values ​​that minimizes the thickness of the cladding 214 without compromising light transmission through the fiber 202, and / or the amount of flexibility desired for the entire fiber 202. As an example, in an embodiment in which the fiber core 212 has a diameter of about 400 μm, the cladding 214 (and thus the entire fiber 202) may have a diameter of about 460 μm. Additionally, in an embodiment in which the core diameter is smaller, the cladding diameter may be proportionally smaller.

[0039] The overall diameter of the fiber optic cable 200 or the diameter of the outer protective covering 206 may depend on the diameter of each individual fiber 202, the number of fibers 202 included in the cable 200, the diameters of the cooling tubes 204 and thermal filler 210, and / or the thickness of the outer protective covering 206. As an example, in the illustrated embodiment, the fiber optic cable 200 includes a bundle of eight ZBLAN optical fibers 202, each having a diameter of approximately 500 microns, and the outer protective covering 206 having a diameter of approximately 5 millimeters (mm).

[0040] The ZBLAN optical fiber 202 is improved or modified prior to fabrication of the optical fiber cable 200 using one or more annealing methods, such as, for example, method 300 shown in Figure 6 and / or method 500 shown in Figure 8. These methods are configured to optimize the fiber 202 for longer transmission by removing or reducing defects that cause scattering losses in the ZBLAN core and cladding. Furthermore, whereas conventional methods for improving substantial amounts of ZBLAN fiber require travel to space (e.g., in a LEO satellite or the International Space Station) to obtain the required low or zero gravity environment, the annealing methods described herein can be accomplished without leaving Earth or using aircraft.

[0041] Generally, these methods involve treating very short segments of prefabricated ZBLAN fiber, such as the optical fiber 202 shown in FIG. 4, to remove crystalline and other defects in the fiber, thus improving the prefabricated fiber. According to an embodiment, the process reduces the glass transition temperature (T g ) well above the crystallization temperature (T x ) is higher than the melting temperature (T m For example, ZBLAN fiber has a T of about 260 degrees Celsius (°C). g and T of about 352°C. x and T of about 450°C m In an embodiment having a tem- perature of about 370°C, the ZBLAN fiber is subjected to an annealing temperature (T aThe process involves heating the ZBLAN fiber to the annealing temperature while subjecting it to the Earth's gravitational acceleration (e.g., 9.8 meters per second per second (m / s)) for a predetermined period of time to mimic a free fall or microgravity environment. 2 The process then further comprises accelerating the melt to a quenching temperature (T q ) rapidly cooling or quenching the fiber. In some embodiments, the quenching temperature is about 10-20° C. below the annealing temperature. For example, in embodiments where the annealing temperature is about 370° C., the quenching temperature can be about 350° C. To help avoid introducing new crystallites during this process, the cooling step is initiated while the fiber is still in free fall, thus ensuring that the annealing step is completed before gravity becomes present.

[0042] The process of perfecting the ZBLAN fiber can be monitored in situ using a laser and photodetector combination or other device that can measure in real time the scattering profile of the fiber or the amount of incident light scattered by defects in the material. The scattering profile indicates the crystallite fraction of the ZBLAN fiber and can therefore be used to determine the effectiveness of the annealing process. If the real-time monitoring results indicate a high crystallite fraction, the process can be repeated through multiple cycles until the optimal fiber loss index is achieved.

[0043] 5 illustrates an exemplary acceleration profile 250 of a ZBLAN fiber during processing described herein, according to an embodiment. As shown, the acceleration profile 250 varies over three time periods. During a first time period t1, the fiber moves from zero acceleration (a=0) to approximately 9.8 m / s 2 The standard free-fall acceleration or gravity (g o ) during this first period. Also, during this first period, the fiber is accelerated from the starting temperature to the annealing temperature T a(e.g., 370° C.). This first period t1 may also be referred to as the “ramp up” period. During a second period t2, the fiber continues to move with the acceleration of gravity. During the second period, the fiber continues to be heated to the annealing temperature or is held at the annealing temperature for a predetermined length of time. During a third period t3, the fiber decelerates and returns to rest. During the third period, the fiber is heated to the quench temperature T q The mixture is cooled to .

[0044] In an embodiment, the second period t2 includes a first predetermined length of time for heating the fiber and a second predetermined length of time for cooling the fiber. The first length of time can be considered as the annealing period of the fiber since it includes the period during which the fiber is annealed or heated to the annealing temperature. The second length of time forms part of the cooling period of the fiber. This cooling period also includes at least a portion of the third period t3, i.e. at least a portion of the pre-set length of time required to cool the fiber to the quenching temperature. According to an embodiment, the second length of time is located at the end of the second period t2 so that the cooling period starts during the acceleration. This ensures that the fiber is still in free fall when the fiber temperature drops below the annealing temperature, thus preventing the formation of new crystallites while the fiber is cooling. In various embodiments, the first length of time is longer than the second length of time. In some embodiments, the length of the annealing period and the length of the cooling period are substantially equal.

[0045] The exact length of time for each of the three periods (t1, t2, and t3) can be determined based on a number of factors. For example, the first period can depend on the acceleration rate of the fiber and the heating rate of the element used to heat the fiber. The second period can depend on the free fall acceleration as well as the distance the fiber travels during acceleration (e.g., free fall descent) and the length of the fiber to be annealed. The third period can depend on the critical cooling rate (CCR) associated with the ZBLAN fiber and the deceleration rate of the fiber. As an example, in some embodiments, the ZBLAN fiber has a critical cooling rate of 40° C. / s. In such a case, a second period of about 320 milliseconds (ms) may be required for a fiber length of about 1 meter, with the first and third periods being much shorter (e.g., 100 ms). While FIG. 5 shows periods t1 and t3 as being approximately equal, in other cases, these two periods can vary or differ from one another, for example, depending on the factors discussed above.

[0046] In some embodiments, the rate or speed at which the fiber accelerates during a first period of time can be determined based on certain properties of the ZBLAN fiber, such as the scattering and absorption levels of the fiber length at a given wavelength (e.g., 650 nanometers (nm)), and the mechanism (e.g., actuator) used to put the fiber into free fall or otherwise release the fiber into a gravitational field. Similarly, the rate or speed at which the fiber decelerates during a second period of time can be determined based on the same fiber properties and the mechanism (e.g., gripper or brake) used to apply a frictional force to slow the fiber's motion.

[0047] FIG. 6 illustrates a first exemplary process or method 300 for removing defects from a length of optical fiber including a fiber core and a cladding surrounding the fiber core. In an embodiment, the optical fiber can be the same as or substantially similar to the optical fiber 202 illustrated in FIG. 4. FIG. 7A illustrates an exemplary fiber refining system 400 configured to remove defects from a length of ZBLAN fiber. In some embodiments, the system 400 can be used to perform the process 300. Thus, in the following paragraphs, the process 300 is described in relation to the system 400 for ease of explanation. However, it should be understood that in other embodiments, the process 300 can be performed using other systems or devices capable of annealing ZBLAN fiber.

[0048] Referring initially to FIG. 7A, according to an embodiment, a fiber improving system 400 includes a chamber or tower 402 (also referred to as a "drop tower") and one or more annealing units 404 movably disposed within the tower 402 and configured to process a given segment of optical fiber 406. The tower 402 can be configured to mimic a microgravity environment by subjecting each annealing unit 404 to a free fall condition for a predetermined period of time (e.g., the second period shown in FIG. 5). In one example embodiment, the tower 402 is about 44 meters tall and configured to provide at least 3 seconds of free fall conditions to process a segment of optical fiber 406 that is about 10 meters long. Although FIG. 7A illustrates the tower 402 including annealing units 404a and 404b, it should be understood that in other embodiments, the tower 402 can include only one annealing unit 404 or more than two annealing units 404. In an embodiment, the fiber improving system 400 further includes one or more processors configured to communicate with the tower 402, the one or more annealing units 404, and / or various other components of the system 400 and to execute the process 300 or otherwise control the components of the system 400 to improve the optical fiber 406 in accordance with the techniques described herein.

[0049] 7B illustrates an exemplary annealing unit 404, according to an embodiment. As shown, an optical fiber 406 is configured to be disposed within the annealing unit 404 and subjected to free fall or gravitational acceleration when the unit 404 is dropped or released within the tower 402. The optical fiber 406 includes a ZBLAN fiber core and a cladding disposed about the fiber core, and can be substantially similar or identical to the optical fiber 202 illustrated in FIG. 4. Although FIG. 7B illustrates the optical fiber 406 completely contained within the annealing unit 404, in other embodiments, the annealing unit can be configured such that a portion of the optical fiber is contained and a remaining portion is disposed outside the annealing unit.

[0050] Referring again to FIG. 7A, the tower 402 further includes a movable component 407 coupled to one or more annealing units 404 and configured to move each annealing unit 404 from a higher elevation to a lower elevation in a free-fall motion, as shown, for example, by annealing unit 404a. The movable component 407 can be further configured to move the annealing unit 404 from the lower elevation back to the higher elevation, as shown, for example, by annealing unit 404b. According to an embodiment, the distance h between the higher elevation and the lower elevation can be selected to ensure that the free-fall motion continues long enough to cause at least one improvement of a given length of ZBLAN fiber or to complete at least one cycle of the annealing and cooling process described herein (e.g., method 300 shown in FIG. 6). In some embodiments, the distance h is selected to allow for the completion of multiple annealing cycles within one fall. The time (in milliseconds) required for the free fall period (e.g., second period t2) in each cycle, as well as the length of the acceleration (or ramp-up) and deceleration periods (e.g., first and third periods t1 and t3) can be calculated using the acceleration profile 250 shown in FIG. 5. The acceleration profile 250 can also determine the length of fiber that can be processed within one cycle. In one exemplary embodiment, the distance h is about 44 meters (m), the annealing unit 404 takes about 3 seconds to travel this distance, and the annealing unit 404 is configured to process about 10 meters of fiber within this time (e.g., 10 m / cycle).

[0051] In some embodiments, the movable component 407 includes a pulley system made up of one or more pulleys 408 and one or more cables 410 slidably coupled to the pulley(s) 408. Each cable 410 can be slidably coupled to at least one annealing unit 404, and the pulley system 407 can be configured to carry and support the units 404 as they move from an elevated position to a lower position and then back to the elevated position.

[0052] For example, in the illustrated embodiment, the pulley system 407 includes a first pulley 408a disposed at or adjacent to the high level and a second pulley 408b disposed at or adjacent to the low level. As illustrated, the cable 410 can form a loop around the pulleys 408a and 408b. The pulleys 408a and 408b can be configured to rotate in two directions: a first direction to move the annealing unit 404 from the high level to the low level, and a second direction to move the annealing unit 404 from the low level back to the high level. The pulley system 407 can be configured to place the annealing unit 404 in a free fall as the unit 404 slides down the cable 410 toward the low level. For example, the cable 410 can be configured to provide zero or minimal frictional force to the annealing unit 404 as the unit 404 moves toward the low level. Upon reaching the low elevation, pulleys 408a and 408b can both rotate in a second direction to pull cable 410 and annealing unit 404 attached to cable 410 back along the same path to the high elevation.

[0053] In other embodiments, pulley system 407 may include multiple independent pulley systems, each coupled to a separate annealing unit 404. In such cases, the annealing units 404 may be independently dropped from a higher elevation to a lower elevation on separate cables and independently pulled back to a higher elevation using separate pulleys. Other configurations are also envisioned for the movable components 407, including, for example, a lift system configured to drop the annealing units from a higher elevation onto a platform located at a lower elevation and then lift the platform and annealing units back up to the higher elevation.

[0054] In an embodiment, the tower 402 further includes a brake system 411 coupled to the movable component 407 and configured to control movement of the movable component 407 and / or movement of the annealing unit 404 coupled to the movable component 407. For example, in the illustrated embodiment, the brake system 411 can be coupled to one or more of the pulleys 408 and / or cables 410 and can be configured to stop the free-fall acceleration of the annealing unit 404 by arresting rotation of the pulley(s) 408 in a first direction or otherwise preventing movement of the cable 410 between the first pulley 408a and the second pulley 408b. By way of example, the brake system 411 can include one or more brakes (not shown) coupled to the cables 410 and / or one or more pulleys 408 and can be configured to activate the brakes when a stopping motion is desired. In some cases, the brake system 411 can be used to stop the annealing unit 404 at a low point when it is moving in a first direction and at a high point when it is moving in a second direction. In some embodiments, the brake system 411 is further configured to initiate a free-fall movement of the annealing unit 404 by releasing the brake to allow the pulley 408 to rotate in the first direction and / or the cable 410 to otherwise move freely towards the low point.

[0055] 7B, each annealing unit 404 includes a heating chamber 412 that heats the optical fiber 406, or specifically, a given segment 406a of the optical fiber 406 disposed within the chamber 412. The annealing unit 404 further includes one or more components that feed incremental portions of the optical fiber 406 through the heating chamber 412. Specifically, the annealing unit 404 includes a first spool 414 configured to hold or store a length of unmodified or pre-annealed optical fiber 406 and feed the unmodified optical fiber 406 into the heating chamber 412. The annealing unit 404 also includes a second spool 416 configured to receive and store a length of modified or annealed optical fiber 406, including the modified segment of optical fiber 406, that exits the heating chamber 412. Thus, the entire length of optical fiber 406 may be initially stored on the first spool 414 and gradually transferred to the second spool 416 as more and more of the optical fiber 406 is processed by the system 400. The annealing unit 404 may also include one or more pulleys or reels to help guide the optical fiber 406 between the first spool 414, the heating chamber 412, and the second spool 416. According to an embodiment, each segment 406a received in the heating chamber 412 may have a substantially uniform length, such as, for example, about 10 meters (m). The exact length of the segment 406a may depend on the distance available for free fall (e.g., distance h in FIG. 7A) and / or the physical constraints of the annealing unit 404.

[0056] According to an embodiment, the heating chamber 412 heats a given segment 406a of the optical fiber 406 to a crystallization temperature (T x ) higher than the glass transition temperature (T g ) is much higher than the melting temperature (T m) to a first temperature below 352°C. Thus, the first temperature can be high enough to remove crystalline material in the fiber core and cladding, but low enough to avoid completely melting the glass. In an embodiment, ZBLAN fiber has a glass transition temperature of about 260°C, a crystallization temperature of about 352°C, and a melting temperature of about 450°C. Thus, the first temperature can be anywhere between 352°C and 450°C. In one embodiment, the first temperature is about 370°C.

[0057] As described herein, the segment 406a remains at the first temperature while the annealing unit 404 is in free fall. For example, the heating chamber 412 can be configured to heat a given segment 406a to the first temperature just before the annealing unit 404 begins its free fall motion, and can continue to heat the given segment 406a during this free fall motion to keep the first segment 406a at the first temperature for a predetermined time (i.e., the annealing period). According to an embodiment, the predetermined time can depend on the length of the segment 406a, as well as other factors described herein.

[0058] In an embodiment, the heating chamber 412 includes a heating coil or any other suitable heating element that can be precisely controlled to a specific temperature. For example, the heating chamber 412 can include a ceramic or metal heating element that can be set to a desired temperature using an input value. In one example embodiment, the heating element has a specific heat capacity of approximately 0.888 J / g·° C. to ensure a sufficiently rapid temperature change of the heating element.

[0059] In some embodiments, the heating chamber 412 further includes a thermocouple or other device that monitors the real-time temperature of the heating element and causes the heating element to adjust its output temperature as needed. For example, a thermocouple can be electrically connected to the heating element to cause the heating element to increase or decrease its output temperature depending on how the real-time temperature reading compares to a desired temperature value.

[0060] In some embodiments, the heating chamber 412 further includes a separate processor that controls the operation of these heating elements and thermocouples. In other embodiments, the heating chamber 412 is electrically coupled to the processor 418 of the annealing unit 404, with the processor 418 configured to manage the heating functions of the heating chamber 412. In yet other embodiments, the heating chamber 412 can be electrically coupled to one or more other processors of the system 400 that perform the operations described herein.

[0061] The annealing unit 404 anneals the heated segment 406a to a crystallization temperature (T x ) is lower than the glass transition temperature (T g The annealing unit 404 may further be configured to rapidly cool or quench the heated segment 406a to a second temperature greater than the first temperature (i.e., the first temperature). In one example embodiment, the second temperature is about 350° C., or about 10° C.-20° C. less than the first temperature. The annealing unit 404 may also be configured to cool the heated segment 406a at a critical cooling rate associated with the optical fiber, which determines how long the cooling process takes (i.e., the cooling period). In an embodiment, the critical cooling rate for ZBLAN fiber is 40° C. / s. In such a case, it takes about 2 seconds to cool down a fiber segment 406a having a length of about 10 meters.

[0062] In some embodiments, the fiber segment 406a can be cooled upon exiting the heating chamber 412. For example, the second spool 416 can be configured to pull a given segment 406a of the optical fiber 406 out of the heating chamber 412 at a rate or speed selected based on a critical cooling rate and the ambient temperature of the annealing unit 404 such that the heated segment 406a cools to the second temperature upon reaching the second spool 416. In other embodiments, the given fiber segment 406a can be cooled to the second temperature in the heating chamber 412. For example, the temperature of the heating chamber 412 can be rapidly reduced to the second temperature to quench the heated segment 406a. In such cases, the heating element can be reduced to the second temperature, for example, by reducing or removing the amount of current applied to the heating element.

[0063] As shown in Figure 7B, the annealing unit 404 further includes one or more processors 418 (also referred to herein as "processors 418") configured to control one or more functions of the annealing unit 404, e.g., according to process 300 of Figure 6. In other embodiments, the one or more processors 418 may be included in another component of the system 400 and configured to communicate with the annealing unit 404 and / or components included in the annealing unit 404 to control the operation of the annealing unit 404.

[0064] In some embodiments, a processor 418 is electrically coupled to the heating chamber 412 to control a temperature setting of a heating element within the chamber 412. For example, the processor 418 can increase the temperature setting to a first temperature during annealing. The processor 418 can also be configured to increase or decrease the temperature setting based on temperature readings received from a sensor (e.g., a thermocouple) disposed at or within the heating chamber 412.

[0065] In some embodiments, a processor 418 is electrically coupled to the first and second spools 414 and 416 to control the movement of the spools, including the speed and direction of rotation of the spools. For example, the processor 418 can be configured to rotate the second spool 416 in a first direction to pull a given segment 406a out of the chamber 412 and pull a subsequent segment 406b of the optical fiber 406 into the chamber 412. The processor 418 can also be configured to rotate the first spool 414 in a second direction opposite the first direction to reverse the direction of travel of the optical fiber 406, for example, when the given segment 406a must be returned to the heating chamber 412 for further processing.

[0066] The processor 418 may also be configured to control the speed at which the first and / or second spools 414 and 416 rotate, and thus the speed or rate at which the optical fiber 406 enters and leaves the heating chamber 412. In some embodiments, the rotational speed of the second spool 416 is selected such that when the heated segment 406a exits the chamber 412, the segment 406a cools rapidly to the second temperature at a critical cooling rate associated with the optical fiber. For example, if the heated segment 406a has a length of 1 meter and the spool size or circumference of the spool is also about 1 meter, the spools 414, 416 may be configured to rotate at a speed or rate of 1 revolution per second to deliver 1 meter of fiber (or one fiber segment 406a) per second to the heating chamber 412. In such an embodiment, the annealing unit 404 may be configured to process 1 meter of fiber per second. As will be appreciated, the rotational speed may be adjusted as needed to accommodate larger (e.g., 10 meter long) segments of fiber.

[0067] In various embodiments, the annealing unit 404 performs a post-annealing analysis of the given segment 406a to determine whether further processing is required for optimal results. Specifically, the annealing unit 404 further includes one or more lasers or other sensors that monitor or measure the scattering profile of the segment 406a after the cooling step is completed. The measurement information can be provided to the processor 418 for real-time analysis. The processor 418 can be configured to determine a fiber loss value of the annealed segment 406a based on the measurement information and compare the measurement to a fiber loss threshold stored in the memory. If the threshold is not met, the processor 418 can be configured to return the segment 406a to the heating chamber 412 for further processing, for example, by rotating the second spool 416 in a second direction (e.g., clockwise) to move the given segment 406a in the opposite direction.

[0068] Specifically, a laser (e.g., a 632 nanometer (nm) laser) can be configured to direct light toward the fiber segment 406a after it exits the heating chamber 412 or while it is inside the chamber 412, depending on where the cooling process takes place. The laser can be suitably located within the heating chamber 412 or at another location in the annealing unit 404. The annealing unit 404 can also include a photodetector that is positioned opposite the laser such that the fiber segment 406a passes between the laser and the photodetector or across a line of sight established between the two devices. The photodetector can be configured to receive the light that has passed through the fiber segment 406a and generate an output (e.g., a current value) that represents the amount of laser power or laser light detected. For example, the photodetector can be configured to measure the amount of red light (e.g., 650 nm) that is not scattered by the crystal or that can pass straight through the fiber glass.

[0069] A processor 418 may be electrically coupled to the photodetector and configured to compare the photodetector output to a threshold or expected current amount. If the measurement is too low, the processor 418 may place the fiber segment 406a back into the heating chamber 412 and process it again. In some embodiments, the annealing and cooling process may be repeated until an optimal scattering coefficient or other fiber loss metric for a given wavelength of light is achieved (e.g., 0.1 decibels per kilometer (dB / km) at 650 nm).

[0070] Referring again to FIG. 6, process 300 will now be described with reference to components of system 400. In an embodiment, process 300 may be implemented using one or more processors of system 400, including, for example, processor 418. As shown, process 300 begins at block 302 with placing or positioning a given segment of optical fiber (e.g., fiber segment 406a) in a heating chamber (e.g., heating chamber 412) of an annealing unit (e.g., annealing unit 404) for processing or refinement. The fiber segment may be moved into the heating chamber by rotating a spool (e.g., spool 414) holding the pre-annealed fiber in a first direction toward the heating chamber. In block 304, the fiber segment is heated to a crystallization temperature (T x ) is higher than the fiber melting temperature (T m ) to a first temperature that is less than about 370°C. For example, the first temperature can be about 370°C or any other value between 352°C and 450°C.

[0071] In block 306, the fiber segment in the annealing unit is annealed to a temperature equal to the gravitational acceleration of the Earth (e.g., 9.8 m / s 2The annealing unit is dropped or moved from a high elevation to a low elevation using a free-fall motion such that the annealing unit accelerates at a rate of 100 rpm (100 rpm). The free-fall motion can be achieved by controlling the movement of a movable component (e.g., pulley system 407) coupled to the annealing unit. The movable component can also be configured to maintain the free-fall motion for a minimum time (e.g., 3 seconds). In block 308, the temperature of the fiber segment is maintained at a first temperature for a first period of time during the free-fall motion. (This first period of time is also referred to herein as the "annealing period.")

[0072] At block 310, the fiber segment is cooled to a second temperature for a second period of time (also referred to herein as the "cooling period"). The second temperature is the crystallization temperature (T x ) is below the glass transition temperature (T g ) In one example embodiment, the second temperature is about 350° C., or about 10° C. to 20° C. lower than the first temperature. Once the second period of time has expired, the first treatment cycle may be considered complete.

[0073] According to an embodiment, the second time period can begin while the fiber segment is in free-fall motion and end after the free-fall motion has stopped or while the fiber segment is decelerating (e.g., within the third time period t3 of FIG. 5). Thus, the time allotted for free-fall can be spent heating and at least partially cooling the fiber segment. In some embodiments, the first time period is substantially equal to the second time period. In other embodiments, the second time period can be longer than the first time period. As will be appreciated, the exact length of the first time period can be determined based on the physical length of the fiber segment and other factors described herein.

[0074] At block 312, the annealing unit is moved from a low elevation to a high elevation using a movable component. At block 314, one or more processors (e.g., processor 418) of the annealing unit determine whether the processed fiber segment meets a fiber loss threshold stored in the unit's memory. If the determination at block 314 is "no" (i.e., the threshold is not met), the process 300 returns to block 304 to begin processing the fiber segment again (i.e., repeating blocks 304-314). If the determination at block 314 is "yes" (i.e., the threshold is met or exceeded), the process 300 proceeds to block 316.

[0075] At block 316, the one or more processors determine whether any subsequent fiber segments remain in the pre-annealed fiber spool (e.g., first spool 414). If the determination at block 316 is "no," then process 300 ends. If the determination at block 316 is "yes," then process 300 returns to block 302 to begin processing the next fiber segment. Thus, process 300 can be repeated any number of times until the entire length of pre-annealed fiber is sufficiently improved or a target fiber loss threshold (e.g., less than 0.1 dB / km at 650 nm) is met.

[0076] FIG. 8 illustrates a second exemplary method or process 500 for removing defects from a length of optical fiber including a fiber core and its surrounding cladding, according to an embodiment. As an example, the optical fiber can be the same as or similar to the optical fiber 202 illustrated in FIG. 4. FIG. 9 illustrates another exemplary fiber improvement system 600 configured to remove defects in a length of ZBLAN fiber. In some embodiments, the system 600 can be used to perform the process 500. Thus, in the following paragraphs, the process 500 is described in relation to the system 600 for ease of explanation. However, it should be understood that in other embodiments, the process 500 can also be performed using other systems or devices capable of annealing ZBLAN fiber.

[0077] Referring initially to FIG. 9, according to an embodiment, a fiber improving system 600 includes an acceleration chamber 602 and an annealing unit 604 movably disposed within the chamber 602 and configured to process a length of optical fiber 606. The optical fiber 606 includes a ZBLAN fiber core and a cladding disposed around the fiber core, and is substantially similar or identical to the optical fiber 202 shown in FIG. 4. The acceleration chamber 602 can be configured to mimic a microgravity environment by subjecting the annealing unit 604 (also referred to as a "spindle") to a free fall for a predetermined period of time (e.g., the second period t2 shown in FIG. 5). In one example embodiment, the acceleration chamber 602 is about 0.5 meters high and configured to provide a free fall of about 320 milliseconds to process a segment of optical fiber 606 that is about 3 inches long.

[0078] As shown in Figure 9, the annealing unit 604 has a generally cylindrical shape with a central opening for receiving the optical fiber 606. The annealing unit 604 also includes a clamping system 608 and a heating chamber 612 disposed adjacent to one another within the central opening as described in more detail herein with respect to Figure 11. In an embodiment, the clamping system 608 can be configured to grip or hold a given segment 606a of the optical fiber 606 within the hollow interior 613 of the heating chamber 612 as the annealing unit 604 free falls through the acceleration chamber 602. The clamping system 608 can be configured to release the processed segment 606a once the segment 606a has been sufficiently processed (annealed and quenched) and to grip a new or next segment of the optical fiber for processing. This release and gripping action can occur at any suitable time or position in the acceleration chamber 602, such as when the annealing unit 604 returns to the top or starting position of the acceleration chamber 602, after the annealing unit 604 has reached the top, or while the annealing unit 604 is still at the bottom of the chamber 602. In this manner, each drop and free fall acceleration of the annealing unit 604 can be used to process the optical fiber 606 segment by segment.

[0079] As shown, the system 600 further includes a first spool 614 configured to hold or store a length of the optical fiber 606 before annealing, and a second spool 616 configured to hold or store a length of the optical fiber 606 after annealing. As described in more detail herein, the system 600 also includes one or more processors 618 (also referred to herein as "processors 618") configured to control the operation of one or more components of the system 600, such as, for example, the acceleration chamber 602, the annealing unit 604, the heating chamber 612, the clamping system 608, and / or the spools 614, 616. In some embodiments, the one or more processors 618 are configured to perform the process 500 shown in FIG. 8 or otherwise control components of the system 600 to improve the optical fiber 606 in accordance with the techniques described herein.

[0080] As shown, the first spool 614 can be positioned adjacent to an entrance of the acceleration chamber 602, and the second spool 616 can be positioned adjacent to an exit of the acceleration chamber 602. In operation, the first spool 614 can be rotated in a first direction to allow the optical fiber 606 to move from the first spool 614 through the acceleration chamber 602 onto the second spool 616 after processing. As shown, the fiber 606 passes through the entire chamber 602 within which the annealing unit 604 and the heating chamber 612 are located. In some cases, the second spool 616 and / or the first spool 614 can be rotated in a second direction opposite to the first direction to move the optical fiber 606 in the reverse direction through the acceleration chamber 602, for example, if a segment of the fiber 606 must be reprocessed or further improved as described herein.

[0081] 10A-10C, the annealing unit 604 has a generally annular outer wall 619 extending between an upper end 615 and a lower end 617 of the unit 604, and has an open center 620 configured to accommodate the heating chamber 612 and the clamping system 608. In some embodiments, the distance y between the upper end 615 and the lower end 617 is about 3 inches. In other embodiments, the annealing unit 604 can be longer or shorter depending, for example, on the height of the acceleration chamber 602 and / or the length of the optical fiber 606 to be processed in a given cycle. Although not shown, the heating chamber 612 can be coupled to at least one of the open upper end 615, the open lower end 617, and / or the outer wall 619 of the annealing unit 604.

[0082] The heating chamber 612 can be configured to receive the optical fiber 606 through a hollow interior 613 as it passes through the annealing unit 604. The hollow interior 613 can be defined by an open upper end where the fiber segment is received into the chamber 612 and an open lower end where the fiber segment can exit the chamber 612. The heating chamber 612 further includes a heating coil or other suitable heating element that can be precisely controlled to a desired temperature. The heating element can be configured to form the hollow interior 613 or to otherwise surround the fiber segment 606a disposed within the heating chamber 612. For example, in some embodiments, the heating element can be arranged in an annular shape such that the walls of the heating element form the hollow interior 613.

[0083] In some embodiments, the heating chamber 612 includes a ceramic heating element. In other embodiments, the heating chamber 612 includes a metal heating element. In one example embodiment, the heating element is configured to have a specific heat capacity of about 0.888 J / g·° C., which ensures fast temperature changes of the heating element. The heating chamber 612 can be configured to heat a given segment of the optical fiber 606 to a first temperature that is greater than the crystallization temperature of the optical fiber 606 and less than the melting temperature of the fiber 606, similar to the heating chamber 412 of FIG. 7B. For example, in some embodiments, the first temperature is about 370° C.

[0084] In some embodiments, the outer wall 619 of the annealing unit 604 includes a plurality of longitudinal openings 622 extending from the upper opening end 615 to the lower opening end 617 and distributed substantially evenly along the entire circumference of the wall 619, giving the annealing unit 604 a basket-like appearance as shown in FIGS. 10A-10C. (For ease of illustration, FIG. 9 illustrates the outer wall 619 with a flat surface.) The exact width of each opening 622 can depend on the circumference of the outer wall 619 and the number of openings 622 desired, or the desired solid structure to space ratio of the outer wall 619. In some embodiments, the heating chamber 612 can also have a partially open (or non-solid) structure. The open walls of the annealing unit 604 and / or the heating chamber 612 can be configured to allow air flow through the annealing unit 604 to help quench the heated segments of the fiber 606 during the cooling portion of the process 500. During such periods, the heating chamber 612 can be configured to turn off the heating element such that the given fiber segment 606a is no longer heated to the first temperature. In some embodiments, air passing through the opening 622 of the annealing unit 604 and / or heating chamber 612 as the annealing unit 604 continues to free fall can be sufficient to rapidly cool the fiber segment 606a to a second temperature below the crystallization temperature but above the glass transition temperature. For example, the second temperature can be about 350° C., or about 10° C.-20° C. lower than the first temperature. In other embodiments, the annealing unit 604 can be configured to allow a suitable gas or liquid to flow through the opening walls of the annealing unit 604 and / or heating chamber 612 for such rapid cooling purposes.

[0085] 11A and 11B are partial enlarged views of the interior of the annealing unit 604 with the walls of the annealing unit 604 and the heating chamber 612 removed to better illustrate the exemplary clamping system 608. As shown, the clamping system 608 includes two movable components 624 disposed opposite each other (or on either side of the heating chamber 612) and adjacent to the hollow interior 613 of the heating chamber 612. The two components 624 are pivotally coupled to the outer wall 619 and / or the heating chamber 612 and configured to move between a non-actuated position shown in FIG. 11A and an actuated position shown in FIG. 11B. Also as shown, the two movable components 624 are disposed adjacent to a fiber segment 606a disposed within the heating chamber 612 and configured to engage or press against either side of the fiber segment 606a when in the actuated position and to keep the fiber segment 606a out of contact when in the non-actuated position.

[0086] According to an embodiment, each movable component 624 (also referred to as an "actuator") includes a gripping portion 626 that engages the fiber segment 606a when moved to an actuated position. In some cases, each gripping portion 626 includes a pad, cushion, or other suitable component that allows the movable component 624 to compress the fiber 606 without causing damage. The gripping portion 626 can be configured to apply a frictional force to the fiber segment 606a sufficient to maintain or hold the segment 606a within the heating chamber 612 while the clamping system 608 is actuated. For example, in some cases, the first spool 614 and / or the second spool 616 can apply a downward force to the optical fiber 606 sufficient to continuously pull the fiber 606 toward the second spool 616. In such a case, the gripping portions 626 must be configured to counter this downward force, for example, by collectively exerting a frictional force sufficient to overcome this downward force or by otherwise preventing the fiber 606 from moving or sliding towards the second spool 616. In this manner, a given fiber segment 606a can be secured (or captured) within the heating chamber 612 so that it can be processed while in the working position.

[0087] In contrast, when the clamping system 608 is in a non-activated or rest position, the components 624 are positioned substantially parallel to each other and to the fiber 606 such that the gripping portions 626 are positioned a distance away from the fiber segment 606 a to avoid contact with the fiber segment 606 a. In such a rest position, the fiber 606 is free to move through the heating chamber 612 and the rest of the annealing unit 604.

[0088] In some embodiments, a gripping portion 626 (also referred to as a "gripper" or "stopper") is located at or near the bottom end of each movable component 624. For example, in FIG. 11A, the components 624 terminate at the gripping portion 626. In such cases, the actuated position can be achieved by pushing or moving the bottom end of each component 624 inward, for example, as shown in FIG. 11B. In other embodiments, the gripping portion 626 can be located at or near the top end of each movable component 624, in which case the gripping portion 626 can be actuated by pushing the top end of each component 624 inward. Other types of devices for gripping a segment of the optical fiber 606 to hold the fiber segment within the heating chamber 612 during processing are also envisioned.

[0089] In an embodiment, the clamping system 608 can be configured to remain on one fiber segment 606a during each free fall cycle, i.e., as the annealing unit 604 moves from the top of the acceleration chamber 602 to the bottom of the chamber 602. The clamping system 608 can be configured to release the given fiber segment 606a upon reaching the bottom and grip a second or next segment of the fiber 606. For example, if the heating chamber 612 is configured to process three inches of fiber at a time, the clamping system 608 can be configured to grip or clamp the fiber 606 at three inch intervals. In this manner, the entire length of the optical fiber 606 can be carefully processed or refined using the system 600.

[0090] In embodiments, the processor 618 may be configured to control one or more functions of the annealing unit 404, the acceleration chamber 402, the spools 614 and 616, and / or other components of the system 600. For example, in some embodiments, the processor 618 is electrically coupled to the first and second spools 614 and 616 to control the movement or rotation, including the rotational speed and direction, of the spools, similar to the processor control of the spools 414 and 416. In some embodiments, the processor 618 may be electrically coupled to the clamping system 608 to control the movement of the moveable component 624 between actuated and non-actuated positions.

[0091] The processor 618 can also be electrically coupled to the chamber 612 to control the temperature setting of the heating element within the heating chamber 612. For example, the processor 618 can set the temperature of the heating element to a first temperature during annealing, and can increase or decrease this temperature as needed, for example, based on real-time temperature readings from a sensor (e.g., a thermocouple) within the chamber 412, to maintain the first temperature during free fall.

[0092] In some embodiments, the processor 618 can be electrically coupled to the acceleration chamber 602 to control the release of the annealing unit 604 at the beginning of a processing cycle or at the top of the chamber 602, and the deceleration and stopping of the annealing unit 604 at the end of a cycle or when the lower end of the chamber 602 is reached. For example, the acceleration chamber 602 can include a frictionless track (not shown) or other device that can move the annealing unit 604 up and down within the acceleration chamber 602, and a braking system (not shown) that can stop the movement of the annealing unit 604 along the track. In such a case, the processor 618 can be electrically coupled to the braking system to stop the movement of the annealing unit 604 at the bottom of the chamber 602, and to the track system to move the annealing unit 604 in a first direction toward the bottom of the unit 604 and a second opposite direction toward the top of the unit 604. Other devices or systems for moving the annealing unit 604 within the acceleration chamber 602 are also contemplated.

[0093] In some embodiments, the system 600 further includes one or more components that perform post-annealing analysis of the processed segment 606a to determine if further processing is required to obtain optimal results. In such cases, the system 600 may include one or more lasers and photodetectors similar to those included in the annealing unit 404. Additionally, the processor 618 may be electrically coupled to these components similar to the processor 418 to monitor or measure the scattering profile of the processed segment 606a (after completion of the cooling process) and determine a fiber loss value of the processed segment 606a in real time based on the measurement information. The processor 618 may compare the determined fiber loss value to a fiber loss threshold and, if the threshold is not met, return the fiber segment 606a to the acceleration chamber 602 for further processing. In one example embodiment, the processor 618 may repeat the annealing and cooling process until an optimal scattering coefficient or other fiber loss indicator for a given wavelength of light (e.g., 0.1 decibels per kilometer (dB / km) at about 650 nm) is achieved.

[0094] Referring again to FIG. 8, process 500 will now be described with reference to components of system 600. Process 500 may be performed using one or more processors included in system 600, including, for example, processor 618. As shown, process 500 begins at block 502 with securing a segment of optical fiber (e.g., fiber segment 606a) within an annealing unit (e.g., annealing unit 604). Specifically, the fiber segment may be secured within or adjacent to a heating element of a heating chamber of the annealing unit (e.g., heating chamber 612) using a clamping system (e.g., clamping system 608) disposed adjacent the heating chamber. The clamping system may be configured to secure or hold a uniform length (e.g., 3 inches) of the fiber segment for each processing cycle (e.g., annealing and cooling). At block 504, the fiber segment is clamped to a crystallization temperature (T x ) is higher than the fiber melting temperature (T m ) to a first temperature that is less than about 370°C. For example, the first temperature can be about 370°C or any other value between 352°C and 450°C.

[0095] In block 506, the annealing unit is moved from a first or starting position in an acceleration chamber (e.g., acceleration chamber 602) to a second or ending position in the same chamber under a gravitational acceleration (e.g., 9.8 m / s 2 ) or using a free-fall motion. In an embodiment, the acceleration chamber 602 is configured to maintain the free-fall motion for a minimum time (e.g., 320 milliseconds). At block 508, the temperature of the fiber segment is maintained at a first temperature for a first period of time during the free-fall motion. At block 510, the fiber segment is cooled to a second temperature for a second period of time. The second temperature is a crystallization temperature (T x ) is below the glass transition temperature (T g) In one example embodiment, the second temperature is about 350° C., or about 10° C. to 20° C. lower than the first temperature. Once the second period of time has expired, the fiber processing cycle may be considered complete.

[0096] According to embodiments, the second period (also referred to herein as the "cooling period") may begin while the fiber segment is in free-fall motion, but may end after the free-fall motion has stopped or while the fiber segment is decelerating (e.g., within the third period t3 of FIG. 5). Thus, the time allotted for free-fall may be spent heating and at least partially cooling the fiber segment. In some embodiments, the first period and the second period may be substantially equal in length. In other embodiments, the second period may be longer than the first period. As will be appreciated, the exact length of the first period will depend on the physical length of the fiber segment, as well as other factors discussed herein.

[0097] At block 512, the annealing unit is moved from the second position in the acceleration chamber 602 back to the first position in the chamber 602. At block 514, one or more processors (e.g., processor 618) of the system 600 determine whether the processed fiber segment meets a fiber loss threshold stored in the memory of the unit. If the determination at block 514 is "no" (i.e., the threshold is not met), the process 500 returns to block 504 to begin processing the fiber segment again (i.e., repeating blocks 504-514). If the determination at block 514 is "yes" (i.e., the threshold is met or exceeded), the process 500 proceeds to block 516.

[0098] At block 516, the one or more processors determine whether a subsequent fiber segment remains in the pre-annealed fiber spool (e.g., first spool 614). If the determination at block 516 is "no," then process 500 ends. If the determination at block 516 is "yes," then process 500 proceeds to block 518, where the processed fiber segment is released from the heating chamber of the annealing unit. For example, the one or more processors may cause the clamping system to release its grip on the fiber or transition to a deactivated state. From block 518, process 500 returns to block 502 to begin processing the next fiber segment. Thus, process 500 may be repeated any number of times until the entire length of pre-annealed fiber is sufficiently improved or a target fiber loss threshold (e.g., less than 0.1 dB / km at 650 nm) is met.

[0099] In an embodiment, each of the processes 300 and 500 may be performed at least in part by at least one data processor executing software stored in a memory, such as, for example, the processor 418, and memory (not shown) included in the annealing unit 404 shown in FIG. 7B, or by the processor 618 and memory (not shown) included in the acceleration chamber 602 shown in FIG. 9. The processor 418 / 618 may interact with one or more other components of the system 400 / 600, respectively, to perform the operations of a given process 300 / 500. The processor 418 / 618 may be any suitable hardware device that executes software instructions retrieved from a memory, such as, for example, a central processing unit (CPU), a semiconductor-based microprocessor (in the form of a microchip or chipset), or another type of microprocessor.

[0100] Each processor 418 / 618 is communicatively coupled to a memory, which can be any suitable memory device suitable for storing software instructions, such as, for example, a volatile storage element (e.g., a random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), a non-volatile storage element (e.g., a ROM, a hard drive, a tape, a CD-ROM, etc.), or any combination thereof. Additionally, the memory can incorporate electronic, magnetic, optical, and / or other types of storage media. In some embodiments, the memory includes a non-transitory computer-readable medium that implements all or part of one or more of the methods described herein and illustrated in FIGS. 5 and 8. The memory can store one or more executable computer programs or software modules that include a set of instructions to be executed, such as, for example, one or more software applications that the processor 418 / 618 can execute to perform the principles disclosed herein (e.g., process 300 / 500). The executable programs can be executed in software, firmware, hardware, or a combination thereof.

[0101] FIG. 12 illustrates an exemplary optical fiber power supply system 700 according to an embodiment. Components of the system 700 can be similar to the optical fiber power supply system 100 illustrated in FIG. 3. For example, the system 700 includes a light source 702 substantially similar to the light source 102 of FIG. 3, a fiber optic cable 704 substantially similar to the fiber optic cable 104 of FIG. 3, and a photodetector 706 substantially similar to the photodetector 106 of FIG. 3. In some embodiments, the fiber optic cable 704 can have a first end 708 coupled to the light source 702, a second end 710 coupled to the photodetector 706, similar to the cable 104, and a plurality of optical fibers extending the length of the cable 704, i.e., the entire length between the first end 708 and the second end 710, substantially similar to the ZBLAN optical fiber 202 illustrated in FIG. 4, for example. For the sake of brevity, the photodetector 706, the light source 702 (also referred to as a "laser light source"), and the fiber optic cable 704 will not be described in detail herein in light of their similarities.

[0102] In an embodiment, the fiber optic power system 700 may be used in or included in an optical fiber network that supplies power to a variety of loads, each of which is connected to or includes an optical-to-electrical converter. For example, the optical fiber network may terminate at a variety of machines and equipment in industrial applications, or at a variety of electronic devices and other devices that are powered using a standard wall outlet in residential or commercial applications. An example of such a network may be the optical power distribution system 800 shown in FIG. 13.

[0103] In some embodiments, the fiber optic cable 704 may be coupled to the light source 702 and / or the light detector 706 via respective fiber optic couplers or connectors 712 and 714 and fiber optic splices 716 and 717 (e.g., mechanical splices, fusion splices, or any other suitable type of splicing device). For example, as shown in FIG. 12, a first end 708 of the cable 704 may be coupled to a first splice 716 that may be connected to a first connector 712 via a second fiber optic cable 713 similar to the fiber optic cable 704. The first connector 712 is also coupled to the light source 702 and configured to pass or transmit optical energy or power from the light source 702 to the fiber optic cables 713 and / or 704. Similarly, a second end 710 of the cable 704 may be coupled to a second splice 717 that may be connected to a second connector 714 via a third fiber optic cable 715 similar to the fiber optic cable 704. A second connector 714 is also coupled to the photodetector 706 and is configured to pass optical power received via the fiber optic cables 715 and / or 704 to the photodetector 706. As will be appreciated, additional splices 716 can also be included if more fiber optic cables are spliced ​​together to provide power via the fiber optic power system 700.

[0104] As shown in FIG. 12 , the light source 702 is configured to be included in a transmitting unit 718 (also referred to herein as an electrical-to-optical ("EO") conversion unit) to convert electrical energy into optical energy (e.g., high-power laser energy) for transmission over the fiber optic cable 704 (similar to the light source 102 of FIG. 1 ). In an embodiment, the electrical energy is power received from an external power source (e.g., a DC power source, an AC power source, etc.) coupled to the transmitting unit 718. The transmitting unit 718 also includes a driver 720 (e.g., a laser diode driver) coupled between the power source and the light source 702 that drives the operation of the light source 702 (e.g., a laser diode) using a power signal received from the power source (or other power input). In some embodiments, the transmitting unit 718 can be coupled to an external control device (e.g., a power control unit 836 shown in FIG. 13 ) that acts as an intermediary between the transmitting unit 718 and the external power source. In such a case, an external control device may manage the amount of power being supplied to the transmitting unit 718 as well as control other operational aspects of the unit 718, for example according to the method 900 of FIG.

[0105] 12, the photodetector 706 is included in a receiving unit 722 (also referred to herein as an optical-to-electrical ("OE") conversion unit) configured to convert optical energy (or power) received via the fiber optic cable 704 into electrical energy (or power). In an embodiment, this electrical energy is used to power one or more electrical loads coupled to the receiving unit 722 (e.g., as shown in FIG. 13).

[0106] In an embodiment, the receiving unit 722 is also configured to transmit control, status, feedback and / or other data signals to the transmitting unit 718 via the same fiber optic cable 704 coupled therebetween. Information contained in such data signals may be received from one or more electrical loads coupled to the receiving unit 722 (e.g., as described with respect to FIG. 13 ) or from a control unit (not shown) coupled to the electrical loads. In such an embodiment, the fiber optic cable 704 may include or be coupled to one or more optical circulators (not shown) that enable bidirectional optical signal transmission through the entire cable 704 or through one or more of the individual fibers included in the cable 704.

[0107] As shown, the receiving unit 722 may further include a first processor 724 (e.g., a microprocessor, microcontroller, or the like) configured to generate one or more digital data signals based on the received information. The receiving unit 722 may also include an optical transmitter 726 coupled to the first processor 724 and the fiber optic cable 704. The optical transmitter 726 may be configured to convert the digital data signal into an optical data signal or other signal that can be transmitted via the fiber optic cable 704. The optical transmitter 726 may be further configured to provide an optical data signal to the fiber optic cable 704 for transmission to the transmitting unit 718. The optical transmitter 726 may be a laser diode (or diode laser) or any other optical device capable of transmitting an optical data signal via the fiber optic cable 704. In some embodiments, the optical transmitter 726 is a laser diode included in a photodiode package of the photodetector 706.

[0108] Similarly, the transmitting unit 718 may further include an optical receiver 728 coupled to the fiber optic cable 704 and a second processor 730 (e.g., a microprocessor, microcontroller, or the like) also included in the transmitting unit 718. The optical receiver 728 may be configured to receive the optical data signal transmitted via the fiber optic cable 704 and convert the received signal back to digital form. The optical receiver 728 may be a photodiode or other optical device capable of monitoring the optical cavity of the laser diode 702 for the optical data signal. In some embodiments, the optical receiver 728 is a monitor diode integrated into the laser diode package of the light source 702. The optical receiver 728 may provide the digital data signal to the second processor 730 for processing, e.g., as described with respect to FIG. 13. In an embodiment, the second processor 730 may provide data extracted from the optical data signal to an external device, such as, for example, a controller or control unit of an external power source (e.g., as shown in FIG. 13).

[0109] 13, an exemplary optical power distribution system 800 is shown that uses a fiber optic cable described herein (e.g., as shown in FIG. 4) as a transmission line to transmit optical power in the form of high power laser energy to multiple locations or loads, according to an embodiment. Optical power distribution system 800 can be used to distribute power over long distances (e.g., between continents, countries, cities, etc.) in any industrial, commercial, residential or personal environment, including, for example, in an aircraft, automobile or residence, and / or in highly unstable areas where power distribution may be at risk.

[0110] In an embodiment, an optical power distribution system 800 may include n optical fiber power systems 801, each of which may be substantially similar to the optical fiber power system 700 shown in Fig. 12. For example, as shown in Fig. 13, the system 800 may include a plurality of electrical-to-optical ("EO") conversion units 818, a plurality of optical-to-electrical ("OE") conversion units 820, and a plurality of optical fiber cables 804, where each EO unit 818 may be substantially similar to the transmitting unit 718 of Fig. 12, each OE unit 822 may be substantially similar to the receiving unit 722 of Fig. 12, and each optical fiber cable 804 may be substantially similar to the optical fiber cable 704 of Fig. 12. Further, each EO unit 818 may be coupled to a respective OE unit 822 of the OE units 822 via a corresponding optical fiber cable 804, and may be configured to transmit optical power ("OPP") to the respective OE unit 822 via the cable 804, as in the optical fiber power system 700. For the sake of brevity, the EO unit 818, the OE unit 822 and the fiber optic cable 804 will not be described in detail here given their similarity to FIG.

[0111] As shown in FIG. 13, each fiber optic power system 801 can be coupled to a respective one of the plurality of electrical loads 832 and to a common power source 834. Additionally, each of the plurality of EO units 818 can be coupled to a power control unit 836 (or power controller) electrically connected to the power source 834. The power source 834 can be any type of power source (e.g., DC or AC) or any other device capable of generating sufficient power to support the electrical loads 832. The power control unit 836 (also referred to as a "master power control unit") can manage the distribution or transmission of the power generated by the power sources 834 to the EO units 818 and can control various other aspects of the power distribution system 800 as described herein. Although FIG. 13 shows a single power source 834 generating power and a single power control unit 836 coupled thereto, in other embodiments, the system 800 can include multiple power sources and / or multiple control units coupled to the plurality of EO units 818.

[0112] According to an embodiment, the power control unit 836 can be configured to control the operation of the power source 834 (e.g., on or off, increasing or decreasing the amount of power generated, etc.), and / or control the operation of each EO unit 818 (e.g., on or off, etc.), and / or manage the power distribution to the individual EO units 818, and / or control other aspects of the power distribution system 800. In some cases, the power control unit 836 manages the power distribution by distributing the generated power evenly among all of the EO units 818. In other cases, the power control unit 836 is configured to optimize the distribution of the generated power among the EO units 818 based on the electrical loads 832 coupled to each EO unit 818.

[0113] For example, the power control unit 836 may adjust or control the optical power delivered to a given OE unit 822 according to the power ratings or power requirements of the corresponding electrical loads 832 (i.e., the loads 832 electrically connected to the OE unit 822) or other status information received from the loads 832. In such a case, the power control unit 836 determines the power requirements of each electrical load 832 based on data provided by the electrical loads 832, and controls one or more characteristics of the optical power output by each corresponding EO unit 818 accordingly, such that the power ultimately received at the corresponding electrical load 832 matches or meets the power requirements of the loads 832.

[0114] The electrical loads 832 can be any type of device or system requiring electrical power, including, for example, a residence or building, an electronic device, a power plant, a vehicle, and others. Each electrical load 832 can be electrically coupled to a respective OE unit 822 using a wired connection (e.g., an electrical cable or the like) or a wireless connection (e.g., a wireless power transmission system). In an embodiment, each electrical load 832 can be configured to transmit data to the OE unit 822 connected to it, for example, using the same wired or wireless connection, or a separate link or connection for data transmission. The data can include status information, connection information, power requirement information, and / or any other information related to management of the electrical power supply. The status information can include, for example, the power factor (or the ratio of real power to apparent power) of the electrical load 832, a power utilization rate or other measurement indicative of the energy efficiency of the load 832, and any other information related to the operation or status of the load 832. The connection information may include, for example, a connection validator or other indication that the load 832 is connected to and / or receiving power from the OE unit 822, as well as other information regarding the electrical connection between the load 832 and the OE unit 822. The power requirement information may include, for example, the power rating of the electrical load 832 or the amount of power required to operate or otherwise support the load 832, as well as other information regarding the power-related needs of the load 832.

[0115] 12, the OE unit 822 may be configured to receive data provided by the electrical load 832 and process the received data using a respective processor (e.g., processor 724 of FIG. 12) or other computing device included in the unit 822. The OE processor may be further configured to generate a data signal (or a digital data signal) based on the received data and provide the data signal to an optical transmitter (e.g., optical transmitter 726 of FIG. 12), which transmits the data to the EO unit 818. As described with respect to FIG. 12, the optical transmitter may convert the digital data signal into an optical data signal (also referred to herein as an optical status signal ("OSS")) suitable for transmission over a fiber optic cable 804 as shown in FIG. 13.

[0116] In an embodiment, the power control unit 836 may be configured to analyze each data signal ("OSS") received from the EO unit 818 to determine whether the optical power supplied to each electrical load 832 meets the power requirements of the load 832 or to identify any power or load shedding needs of the system 800. For example, if a given electrical load 832 requires more optical power than is currently supplied to it ("OPP"), the power control unit 836 may determine whether more optical power can be supplied to the corresponding OE unit 822 by increasing the number of optical fibers in the fiber optic cable 804 being used to transmit the optical power to the corresponding OE unit 822. Additionally or alternatively, the power control unit 836 may determine whether the power source 834 can supply more generated power to the corresponding EO unit 818 to increase the total amount of power available to the load 832. In other cases, the power control unit 836 can control or adjust other characteristics of the EO unit 818 and / or the optical power transmitted from the EO unit 818 to increase the amount of power delivered to the loads 832. In either case, if more power is available, the power control unit 836 can control the EO unit 818 and / or the power supply 834 to ensure that more power is delivered to each electrical load 832 as needed.

[0117] For example, if all optical fibers in the fiber optic cable 804 are already in use and no more power is available because the power source 834 is already operating at maximum capacity, the power control unit 836 may determine that the power source 834 cannot support the power requirements of a given electrical load 832 and, as a result, terminate the optical link between the corresponding EO unit 818 and the OE unit 822. For example, the power control unit 836 may turn off the light source included in the corresponding EO unit 818 or stop transmitting optical power through the fiber optic cable 804 coupled to the EO unit 818.

[0118] In some embodiments, the power control unit 836 can be configured to use techniques similar to those described herein when the amount of power required by the load 832 is less than the amount of power being supplied. For example, the power control unit 836 can reduce the number of optical fibers being used, reduce the amount of generated power being supplied by the power supply 834 to the laser light sources of the EO unit 818, reduce the amount of optical power being output by the EO unit 818, and / or control one or more other characteristics of the EO unit 818 and / or the fiber optic cable 804.

[0119] Thus, system 800 avoids grid inefficiencies by matching the power requirements of each load 832, but may also be configured to use power limiting techniques, as further described herein with respect to method 900 of FIG. 14, to prevent charge build-up and ensure efficient utilization of the OE / EO infrastructure.

[0120] The power control unit 836 may include one or more suitable hardware devices to perform the operations described herein, such as, for example, a processing device (or processor) and a memory device. A processor can be any suitable hardware device that executes software instructions retrieved from a memory device, such as, for example, a central processing unit (CPU), a semiconductor-based microprocessor (in the form of a microchip or chipset), or another type of microprocessor.

[0121] The memory device can be any suitable memory device suitable for storing software instructions, such as, for example, a volatile storage element (e.g., a random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), a non-volatile storage element (e.g., a ROM, a hard drive, a tape, a CD-ROM, etc.), or any combination thereof. Furthermore, the memory device can incorporate electronic, magnetic, optical, and / or other types of storage media. In some embodiments, the memory includes a non-transitory computer-readable medium that implements all or part of one or more of the methods described herein and illustrated in FIG. 14. The memory can store one or more executable computer programs or software modules that include a set of instructions to be executed, such as, for example, one or more software applications that a processor can execute to perform the principles disclosed herein (e.g., process 900). The executable programs can be executed in software, firmware, hardware, or a combination thereof.

[0122] 14 illustrates an exemplary power supply management process or method 900 in an optical fiber power supply system including a transmitting unit having a laser light source, a receiving unit having a photodetector, and a fiber optic cable coupled between the units, according to an embodiment. In some embodiments, the optical fiber power supply system can be substantially similar to any of the optical fiber power supply systems described herein, such as, for example, the optical fiber power supply system 700 illustrated in FIG. 12. In some embodiments, the optical fiber power supply system can be an optical power distribution system, such as, for example, the optical power distribution system 800 illustrated in FIG. 13, or can form part of a larger optical power distribution system (e.g., similar to the optical fiber power supply system 801 of FIG. 13).

[0123] The method 900 may be performed by one or more electronic devices or components of the optical fiber power supply system alone or in combination with one or more other electronic devices. These devices may include, for example, the power control unit 836 shown in FIG. 13, the transmitting unit 718 shown in FIG. 12, and / or the receiving unit 722 shown in FIG. 12. The functions of the method 900 may be performed at least in part by a processor of the device (e.g., the processor of the power control unit 836 and / or the processors 724 and 730 of FIG. 12) executing a software application stored in a memory of the device. In some embodiments, the application may be a computer program stored on a non-transitory computer-readable medium that the processor of the device can execute. The electronic device(s) may not only employ one or more internal devices (e.g., the laser light source 702 and the optical receiver 728 of the transmitting unit, the photodetector 706 and the optical transmitter 726 of the receiving unit 722, etc.) to further perform operations of the method 900, but may also interact or interface with one or more external devices or components coupled to the electronic device, such as an external power source (e.g., the power source 834 of FIG. 13) and an external electrical load (e.g., the electrical load 832 of FIG. 13). In some embodiments, the method 900 may be performed by a power control unit 836 to manage the power supply in each optical fiber power supply system 801 included in the optical power distribution system 800.

[0124] As shown in FIG. 14, the method 902 may begin with step 902, which includes transmitting high power laser energy from a transmitting unit to a receiving unit using a first number n of optical fibers included in a fiber optic cable. In an embodiment, the fiber optic cable includes a plurality of optical fibers, each extending the length of the fiber optic cable and surrounded by a thermal filler. For example, the fiber optic cable may be substantially similar to the fiber optic cable 200 shown in FIG. 4 and may be comprised of optical fibers 202 or any other fiber optic cable capable of transmitting laser energy having a power of about 1 gigawatt over a distance of about 1000 kilometers (km) with a loss of about 0.1 decibels (dB). In such an embodiment, the transmitting unit may transmit optical power to the receiving unit using all, some, or any other number of optical fibers in the fiber optic cable. In some embodiments, the transmitting unit is configured to initially use a first number of optical fibers selected based on a preset value (e.g., one fiber, 50% of the fibers, etc.). In other embodiments, a user or operator of the system may select the first number of optical fibers.

[0125] Step 904 of method 900 includes receiving at a processor a data signal including information regarding the power requirements of an electrical load coupled to the receiving unit, the data signal being transmitted from the receiving unit to the transmitting unit using the same fiber optic cable as that used to transmit the high power laser energy. The power requirement information may include, for example, a power rating of the electrical load, or other indicative of the amount of power required to operate the electrical load. In some embodiments, the data signal may also include additional information, such as, for example, connection information supporting the supply of power to the electrical load, status information indicating a power factor or power utilization rate of the electrical load, or other indicative of the amount of power being used by or received at the load, feedback information including messages from the electrical load and / or the receiving unit, and / or other information described herein.

[0126] According to an embodiment, the data signal is an optical data signal generated by an optical transmitter included in the receiving unit (e.g., optical transmitter 726 in FIG. 12) and transmitted over a fiber optic cable. In such an embodiment, step 904 further includes receiving the optical data signal at an optical receiver included in the transmitting unit (e.g., optical receiver 728 in FIG. 12). In step 906, the optical data signal is converted to a digital data signal, for example using an optical receiver (e.g., a monitor diode), and provided to the processor.

[0127] In an embodiment, the method 900 further includes analyzing the data signal using a processor and controlling the high power laser energy output by the transmitting unit based on the analysis. For example, if the data signal includes electrical load power requirement information, the method 900 includes controlling the high power laser energy output by the transmitting unit based on the power requirements of the electrical load. In various embodiments, the method 900 includes adjusting or controlling one or more characteristics of the transmitting unit and / or the fiber optic cable to control the high power laser energy output.

[0128] Specifically, analyzing the data signal may include identifying power requirement information included in the data signal and determining whether the power requirement included in the data signal exceeds a threshold power amount in step 908. In some embodiments, the threshold power amount may be related to an external power source (e.g., power source 834 in FIG. 13 ) coupled to the transmitting unit, such as, for example, a maximum amount of power that the external power source can generate, or other threshold of the external power source. In other embodiments, the threshold power amount may be related to a light source (e.g., a laser light source) of the transmitting unit, such as, for example, a maximum amount of optical power that the laser can output, or other threshold of the light source. In yet other embodiments, the threshold power amount may be related to a fiber optic cable, such as, for example, a maximum amount of power that the cable can carry over its length, or other threshold of the fiber optic cable. Other threshold amounts related to fiber optic power systems are also contemplated.

[0129] If the determination in step 908 is affirmative, i.e., the power requirements of the electrical load exceed the threshold amount of power, then method 900 proceeds to step 910 which includes controlling the high power laser energy output transmitted by the transmitting unit by interrupting the transmission of high power laser energy from the transmitting unit, i.e., the fiber optic power system interrupts operation of the light source or otherwise stops providing optical power over the fiber optic cable when the power required to operate the electrical load is greater than the amount of power available.

[0130] If the determination at step 908 is negative, i.e., the power requirement does not exceed the threshold, the method 900 proceeds to step 912, which includes determining whether the high power laser energy being output by the transmitting unit or received by the receiving unit meets the power requirement of the electrical load. For example, the processor may compare the amount of optical power detected by the receiving unit to the amount of power required to operate the electrical load to determine whether there is a gap or deficiency at the receiver. If the determination at step 912 is positive, i.e., the power requirement of the electrical load is met, the method 900 may end.

[0131] On the other hand, if the determination at step 912 is negative, i.e., the received laser energy does not meet the power requirement, method 900 may include controlling or adjusting the high power laser energy output by the transmitting unit such that the power requirement is met, or otherwise adjusting the laser output to meet the needs of the corresponding electrical load. The exact manner in which the laser energy output of the transmitting unit is adjusted will depend on a variety of factors, including, for example, the power requirements of the electrical load, the total number of optical fibers contained in the fiber optic cable, the power characteristics of the laser source, and the maximum power capacity of each fiber.

[0132] In some embodiments, the adjustment can be accomplished in step 914 by adjusting the number of optical fibers used to transmit the laser energy from the transmitting unit based on the power requirements of the electrical load to control the form of optical power (OPP) being transmitted through the fiber optic cable. For example, in some cases, the transmitting unit can increase a first number of optical fibers initially used to transmit the laser energy to a second number of optical fibers greater than the first number. In other cases, the transmitting unit can decrease the number of optical fibers used to a third number less than the first number to reduce the amount of optical power being transmitted to the receiving side. Thus, step 914 can further include using a processor to determine the number of optical fibers required to meet the power requirements of the electrical load and instructing the transmitting unit (or a laser source included in the transmitting unit) to use the determined number of optical fibers to transmit optical power to the receiving unit.

[0133] In some cases, adjusting the laser energy output in step 916 can be accomplished by adjusting not only the number of optical fibers, but also the amount of power transmitted through each optical fiber. As an example, initially each optical fiber in a first number of fibers can be operated at about 75% of the fiber's maximum power capacity (e.g., about 10 kilowatts (kW)). If more power is needed, one or more of these fibers can be operated at a higher capacity (e.g., 80%), or additional fibers can be used only up to the capacity needed to meet the power requirements. Similarly, if less power is needed, the total power output can be reduced by controlling or reducing the amount of optical power transmitted through one or more fibers.

[0134] In some cases, the adjustment of the form of laser energy output or optical power in step 916 can be accomplished by adjusting the amount of power output by the laser source according to the power requirements of the electrical load. For example, the power setting of the laser source or the optical power conversion setting of the entire transmitting unit can be increased or adjusted from a first setting to a second setting to increase the amount of optical power transmitted to the receiving unit. As another example, in an embodiment where the laser source is a diode array made up of multiple laser diodes, the laser energy output of the laser source can be adjusted by controlling the number of laser diodes being used to output optical power. For example, the transmitting unit can be configured to turn on or off one or more of the laser diodes in the array depending on the amount of power required to meet the power requirements of the electrical load.

[0135] In some cases, a combination of steps 914 and 916 may be used to meet the power requirements of the electrical load. For example, if the power requirements of the electrical load are not met using all of the optical fibers in the fiber optic cable, the amount of optical power output by the laser source may be increased up to the maximum power capacity of each fiber. In some cases, the high power laser energy output by the transmitting unit is controlled or adjusted based on the power requirements of the electrical load by increasing the amount of optical power output by the laser source and increasing the number of optical fibers used to transmit the laser energy from a first number of fibers to a second number of fibers equal to the total number of optical fibers included in the fiber optic cable.

[0136] In some embodiments, the laser energy output by the transmitting unit may be adjusted temporarily or for only a set period of time, for example to meet peak load demands (e.g., during the day) or other temporary needs of the fiber optic power system. For example, step 914 may further include increasing the number of optical fibers used from a first number to a second number at a first time point (), and decreasing the number of optical fibers back to the first number at a second time point or after a set period of time. Similarly, step 916 may further include increasing the amount of optical power being output by the laser source from a first setting to a second setting at a first time point, and returning it back to the first setting at a second time point or after a set period of time to decrease the amount of optical power being output by the laser source. As will be appreciated, other techniques for temporarily adjusting the form of optical power being transmitted through the fiber optic cable may also be used.

[0137] FIG. 15 illustrates an exemplary fiber optic power delivery system 1000 configured for use in medical applications, according to an embodiment. In some embodiments, the fiber optic power delivery system 1000 can be used to remove or ablate tumors or other unwanted objects within the human body without major surgery. As an example, the fiber optic power delivery system 100 can be used for laser-induced thermotherapy, percutaneous laser ablation of certain tumors (e.g., primary and secondary malignant lung tumors and the like), and other suitable medical procedures (e.g., ureteral stone removal, etc.). The fiber optic power delivery system 1000, like other fiber optic power delivery systems described herein, can adjust its laser energy output according to the needs of the recipient, or in this case, the particular medical procedure being performed, even as these needs change throughout the procedure. For example, when used to ablate or eliminate unwanted objects within a patient's body, the system 1000 can be configured to adjust one or more characteristics of the laser energy output as the size and / or shape of the object changes in response to the laser treatment. As a result, the optical fiber power supply system 1000 can provide a more efficient and accurate ablation method than existing laser-induced thermotherapy and the like.

[0138] As shown in Fig. 15, the system 1000 includes a light source 1002 (or laser source) that emits very high power laser energy, similar to the light source 102 shown in Fig. 3. The system 1000 further includes at least one optical fiber 1004 having a first end coupled to the laser source 1002. During an ablation procedure, a second end of the at least one optical fiber 1004 can be inserted into a body portion of a patient 1006 adjacent an object 1008 to be removed or excised. The optical fiber 1004 can act as a transmission line to direct high power laser energy from the laser source 1002 to the object 1008. Once the procedure is completed, all or a portion of the optical fiber 1004 can be removed from the patient's body and discarded.

[0139] In general, the laser energy emitted through the optical fiber 1004 can be tuned or optimized to achieve ablation of a particular object 1008. For example, the high power laser energy output by the laser source 1002 can be configured to have a wavelength of about 2-3 micrometers (μm) or other suitable wavelength depending on the object 1042 to be ablated. For example, the wavelength can be set at 2.1 μm for tumor ablation and 2.0 μm for ablation of ureteral stones. In some embodiments, the laser source 1002 can be configured to emit pulses of laser energy at a particular rate depending on the medical procedure and / or type of object 1008. For example, the laser source 1002 can be configured to transmit pulses of laser energy at a repetition rate of 50 Hertz (Hz) when shattering ureteral stones. The laser source 1002 can also be configured to transmit pulses of light energy having a particular amount of power (e.g., a pulse output of about 1 Joule (J) per pulse) depending on the particular medical application.

[0140] In embodiments, the laser energy output is adjusted during the ablation procedure to adjust the high power laser energy according to the particular type of object 1008 as well as the physical structure of the object 1008, which changes as ablation occurs. For example, the intensity of the laser energy directed at the object 1008 may be reduced as the object 1008 decreases in size and / or as the object 1008 breaks into multiple pieces. In embodiments, such adjustments may be achieved by controlling one or more features or characteristics of the laser energy output, such as, for example, the power level of the laser energy output by the laser source 1002. In some cases, such adjustments may be made initially prior to the start of treatment, for example, based on information regarding the initial size and / or shape of the object 1008, and may continue to be made during treatment based on status or feedback information regarding the object 1008 or a remainder thereof.

[0141] To this end, the fiber optic power delivery system 1000 further includes a spectrometer 1010 coupled to a second optical fiber 1012 having a distal end disposed at or near the same location within the patient 1006 as the first optical fiber 1004 (i.e., adjacent to the object 1008). The second optical fiber 1012 can be configured to return optical energy detected at the location of the object 1008 to the spectrometer 1010. In an embodiment, the second optical fiber 1012 can be substantially similar to one of the optical fibers 202 shown in FIG. 4. The spectrometer 1010 can be a near infrared (or "NTR") spectrometer or other optical spectroscopy device that can analyze or measure various characteristics of the returning light (or light pulses) and determine the condition of the object 1008 or other incident object based on this analysis. For example, the spectrometer 1010 can measure the intensity of the return light after the initial application of laser energy and analyze the spectral signature of the return pulse to determine whether the laser energy output completely ablated the object 1008 or only partially ablated the object 1008 and / or fragmented the object 1008 into multiple small pieces. The spectrometer 1010 can also analyze the signature of the return pulse to determine the size of the remaining fragments of the object 1008. In some cases, the spectrometer 1010 is configured to analyze the return light by identifying a signature of each return pulse and comparing these signatures to previously acquired signatures of the object 1008 or other prior information to determine how much, if any, of the original object 1008 remains. The spectrometer 1010 can also monitor the signature of the return pulse, including tissue morphology and absorption characteristics, to assess the effectiveness or completeness of the ablation procedure. As will be appreciated, spectrometer 1010 can identify and analyze the different colors of light contained in the return pulse and the spectral structure of the return pulse to make these determinations.

[0142] The fiber optic power system 1000 further includes a control unit 1014 that adjusts at least one characteristic of the laser energy output based on the status information determined by the spectrometer 1012. In an embodiment, the control unit 1014 may control one or more characteristics of the fiber optic power system 1000 that may affect the intensity of the laser energy directed to the object 1008. For example, the control unit 1014 may be configured to adjust the optical power or amount of optical energy emitted from the light source 1002. As another example, the control unit 1014 may be configured to adjust the shape of the laser energy pulse incident on the object 1008 or otherwise change or affect one or more characteristics of the optical fiber 1004 as described herein with respect to FIG. 16 used to deliver the laser energy towards the patient 1006.

[0143] 15, in some embodiments, the control unit 1014 is a stand-alone computing device that communicates with both the spectrometer 1012 and the laser source 1002 via a wired or wireless connection. In other embodiments, the control unit 1014 can be a microcontroller or the like included in the spectrometer 1012, in which case the spectrometer 1012 can be in communication with the laser source 1002. As will be appreciated, the control unit 1014 can nevertheless include a processor and memory (e.g., similar to that of the receiving unit 722 shown in FIG. 12) to perform the operations described herein.

[0144] Additionally, FIG. 16 illustrates a cross-sectional view of an optical fiber 1004 included in the optical fiber power delivery system 1000 of FIG. 15. In an embodiment, the optical fiber 1004 can be configured to allow for control of the pulse shape and / or other characteristics of the laser energy being delivered through the optical fiber 1004. As illustrated, the optical fiber 1004 includes a ZBLAN core 1016, which can be substantially similar to the fiber core 212 illustrated in FIG. 4 and described herein. The optical fiber 1004 further includes a cladding 1018 disposed about the ZBLAN core 1016. The cladding 1018 can be fused or spliced ​​to the core 1016 similar to the cladding 214 of FIG. 4. The fiber optic cable 1004 further includes a protective coating 1020 configured to protect and isolate the ZBLAN fiber core 1016 and cladding 1018. The coating 1020 can be constructed of polyvinyl fluoride ("PVF") or other suitable polymer.

[0145] In an embodiment, the cladding 1018 and coating 1020 can be configured to allow specific control or tuning of one or more characteristics of the laser energy propagating through the core 1016 of the optical fiber 1004. For example, the cladding 1018 can have a periodic structure configured to guide or direct the propagation of the laser energy towards the object 1008. The coating 1020 can be an electroactive polymer that can change size or shape when stimulated by an electric field, such as the electric field applied to the cladding 1018 by the control unit 1014 of FIG. 15. As the coating 1020 expands and / or contracts in response to the electric field, the period of the cladding 1018 of the periodic structure also changes. Correspondingly, the pulse shape of the laser energy propagating through the core 1016 and the amplitude or intensity of each light pulse change, thus controlling the type of light that can pass through the optical fiber 1004. In an embodiment, the control unit 1014 can be configured to impart a particular electric field to the cladding 1018 such that the pulse shape and intensity level of the laser energy incident on the object 1008 is adjusted as needed or according to the current state of the object 1008 (e.g., the number and size of remaining fragments, etc.).

[0146] In some embodiments, the type of light source 1002 included in the fiber optic power delivery system 1000 can be changed or modified depending on the particular medical procedure. For example, to break up ureteral stones, a Ho:YAG laser can be used, which is standard in such surgical procedures.

[0147] In some embodiments, the process descriptions or blocks in the diagrams, such as Figures 6, 8, and 14, may represent modules, segments, or portions of code that contain one or more executable instructions for implementing certain logical functions or steps in a process. As will be appreciated by those skilled in the art, the scope of the embodiments described herein includes any alternative implementations that may perform functions in an order different from that shown or described, including performing functions substantially simultaneously or in reverse order, depending on the functionality involved.

[0148] It should be emphasized that the above-described embodiments, particularly any "preferred" embodiments, are merely possible examples set forth to allow a clear understanding of the principles of the present invention. Many changes and modifications can be made to the above-described embodiment(s) without substantially departing from the spirit and principles of the technology described herein. All such modifications are intended to be included within the scope of this disclosure and protected by the following claims. The present invention includes the following aspects. [1] 1. A fiber optic cable comprising: a length extending between the first end and the second end; A central cooling tube; a plurality of optical fibers disposed radially around the cooling tube, each optical fiber including a fiber core and a cladding disposed around the fiber core; An outer protective cover; an inner thermal filler disposed between the outer protective cover and the central cooling tube and surrounding each of the optical fibers; Equipped with the central cooling tube, the outer protective cover, the inner thermal filler, and the plurality of optical fibers each extend along the length of the cable; Fiber optic cable. [2] Each optical fiber is made of ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF(ZBLAN) [1] An optical fiber cable as described in [1]. [3] The thermal filler is made of acrylic; [1] An optical fiber cable as described in [1]. [4] the cooling tube includes a cooling material configured to maintain a temperature of the cable below a threshold temperature. [1] An optical fiber cable as described in the above. [5] The cooling material is air. [1] An optical fiber cable as described in the above. [6] Each fiber core has a radius selected from the range of about 300 micrometers (μm) to about 500 μm. [1] An optical fiber cable as described in the above. [7] The cable is capable of transmitting laser energy having a power of about 1 gigawatt over a distance of about 1000 kilometers (km) with a loss of about 0.1 decibels (dB). [1] An optical fiber cable as described in the above. [8] The laser energy has a wavelength of about 2.1 μm. [7] An optical fiber cable as described in the above. [9] The length is at least about 50 km. [1] An optical fiber cable as described in the above.

[10] the plurality of optical fibers includes approximately 8000 optical fibers; [1] An optical fiber cable as described in the above.

[11] the cladding is configured to confine light within the fiber core; [1] An optical fiber cable as described in [1].

[12] the cladding is formed of a fluoride glass material having a lower refractive index than the fiber core;

[11] An optical fiber cable according to the present invention.

[13] Each optical fiber is improved using an annealing method configured to reduce the number of defects in the fiber core. [1] An optical fiber cable as described in [1].

[14] The annealing method includes: The optical fiber is heated to a crystallization temperature (T x ) higher than the melting temperature (T m ) to a first temperature less than moving the optical fiber from a first position to a second position at a first acceleration while the optical fiber is at the first temperature; The optical fiber is heated to a temperature lower than the crystallization temperature of the optical fiber (T g a critical cooling rate associated with the optical fiber to a second temperature greater than the critical cooling rate associated with the optical fiber; The optical fiber cable according to

[13] ,

[15] The first acceleration is the acceleration of gravity.

[14] An optical fiber cable according to the present invention.

[16] The glass transition temperature is about 260° C., the crystallization temperature is about 352° C., and the melting temperature is about 450° C.

[14] An optical fiber cable according to the present invention.

[17] 1. A system for removing defects in a length of optical fiber including a fiber core and a cladding surrounding the fiber core, comprising: A given segment of the optical fiber is heated to a crystallization temperature (T x ) higher than the melting temperature (T m an annealing unit including a heating chamber configured to heat the first temperature therein to a first temperature lower than a heating chamber configured to move the annealing unit from an elevated position to a lower position using a free-fall motion, the heating chamber further configured to maintain the first temperature of the segment of optical fiber during a first period of the free-fall motion; Equipped with The annealing unit anneals the segment of optical fiber to the crystallization temperature (T x ) lower than the glass transition temperature (T g a critical cooling rate associated with the optical fiber to a second temperature greater than a critical cooling rate associated with the optical fiber; After the second period of time has expired, the annealing unit is further configured to transition a subsequent segment of the optical fiber into the heating chamber, and the housing is further configured to move the annealing unit from the lower elevation to the higher elevation. system.

[18] the annealing unit further comprising a first spool configured to feed the optical fiber into the heating chamber and a second spool configured to receive the optical fiber exiting the heating chamber;

[17] The system described in.

[19] the annealing unit further comprising one or more processors configured to rotate the second spool in a first direction to withdraw the given segment from the chamber and withdraw the subsequent segment into the chamber;

[18] The system described in.

[20] the second period of time begins during the free fall motion after the first period of time has ended. The system described in

[19] .

[21] The one or more processors: determining whether a given segment of the optical fiber meets a fiber loss threshold after cooling; if the threshold is not met, rotating the second spool in a second direction opposite to the first direction to return the given segment to the heating chamber for further heating. The system of

[19] , further configured as follows.

[22] The optical fiber is ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF(ZBLAN)

[17] The system described in.

[23] each segment of said optical fiber has a substantially uniform length of at least about 10 meters, a distance between said high point and said low point is at least about 44 meters, and said free fall motion lasts for about 3 seconds.

[17] The system described in.

[24] The critical cooling rate is about 40 degrees Celsius (°C) per second.

[17] The system described in.

[25] The glass transition temperature is about 260° C., the crystallization temperature is about 352° C., and the melting temperature is about 450° C.

[17] The system described in.

[26] 1. A method for removing defects from a length of optical fiber, the length including a fiber core and a cladding surrounding the fiber core, the optical fiber being disposed at least partially within an annealing unit of a system including one or more processors, the method comprising: (a) using the one or more processors, placing a given segment of the optical fiber in a heating chamber of the annealing unit; (b) using the heating chamber and the one or more processors to heat the given segment to a crystallization temperature (T x ) higher than the melting temperature (T m ) to a first temperature less than (c) using the one or more processors to move the annealing unit from a higher elevation to a lower elevation using a free-fall motion; (d) maintaining the given segment at the first temperature for a first period of time using the heating chamber and the one or more processors during the free fall motion; (e) during a second time period, using the one or more processors to measure the crystallization temperature (T x ) lower than the glass transition temperature (T g (c) cooling the optical fiber to a second temperature greater than the critical cooling rate of the optical fiber; (f) after the second period of time, moving the annealing unit from the lower elevation to the higher elevation using the one or more processors; (g) repeating steps (a)-(f) using the one or more processors for each subsequent segment of the optical fiber until the entire length of the optical fiber has been processed; A method comprising:

[27] cooling the given segment includes withdrawing the first segment from the heating chamber at a rate selected based on the critical cooling rate, such that the given segment of optical fiber cools to the second temperature upon exiting the heating chamber. The method described in

[26] .

[28] as the given segment is drawn, a subsequent segment of the optical fiber is drawn into the heating chamber; The method described in

[27] .

[29] prior to step (g), determining, using the one or more processors, whether a given segment of the optical fiber meets a fiber loss threshold; if the threshold is not met, rotating the second spool using the one or more processors in a second direction opposite to the first direction to return the given segment to the heating chamber for further heating; The method according to

[26] , further comprising:

[30] repeating steps (b)-(f) for the given segment to provide the additional heating. The method described in

[29] .

[31] the second period of time begins during the free fall motion after the first period of time has ended. The method described in

[26] .

[32] each segment of optical fiber has a substantially uniform length of at least about 10 meters, a distance from the high point to the low point is at least about 44 meters, and the free fall motion lasts for about 3 seconds. The method described in

[26] .

[33] The optical fiber is ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF(ZBLAN) The method described in

[26] .

[34] The critical cooling rate is at least about 40 degrees Celsius (°C) per second; The method described in

[26] .

[35] The glass transition temperature is about 260° C., the crystallization temperature is about 352° C., and the melting temperature is about 450° C. The method described in

[26] .

[36] 1. A system for reducing defects in a length of optical fiber, the system comprising a fiber core and a cladding surrounding the fiber core, the system comprising: A given segment of the optical fiber is heated to a crystallization temperature (T x ) higher than the melting temperature (T m and a clamping system configured to selectively secure the given segment adjacent to the heating element; and an acceleration chamber configured to house the annealing unit and to move the annealing unit and a given segment of the optical fiber secured within the annealing unit from a first position to a second position at a first acceleration, and to move the annealing unit and the given segment from the second position to the first position at a second acceleration that is lower than the first acceleration; Equipped with a given segment of the optical fiber is heated by the heating element to the first temperature for a first period of time while at the first acceleration; The given segment cools to a glass transition temperature (T) below the crystallization temperature of the optical fiber at a critical cooling rate associated with the optical fiber over a second period of time. g ) to a second temperature greater than the clamping system is configured to release the given segment of the optical fiber after the second period of time and secure a subsequent segment of the optical fiber adjacent to the heating element. system.

[37] a first spool configured to feed the optical fiber into the acceleration chamber and a second spool configured to receive the optical fiber exiting the acceleration chamber. The system described in

[36] .

[38] the acceleration chamber includes one or more processors configured to control movement of the annealing unit between the first position and the second position and to control operation of the clamping system and the heating system included in the clamping system. The system described in

[37] .

[39] The one or more processors: determining whether the given segment of the optical fiber meets a fiber loss threshold prior to releasing the given segment of the optical fiber; if the threshold is not met, repeating moving the annealing unit from the first position to the second position at the first acceleration while heating the given segment to the first temperature. The system of

[38] , further configured as follows.

[40] the annealing unit includes a plurality of openings extending along a length of the annealing unit and configured to allow airflow through the unit to cool the given segment during the second time period; The system described in

[36] .

[41] The heating element is a coil disposed at the center of the annealing unit, and the optical fiber passes through the center of the coil. The system described in

[36] .

[42] the clamping system includes two actuators disposed adjacent either side of the heating element and configured to move between a first position that secures a given segment of the optical fiber adjacent to the heating element and a second position that releases the segment, each actuator terminating in a gripping portion configured to compress the optical fiber when the clamping system is in the first position. The system described in

[41] .

[43] the second time period begins after the end of the first time period during the first acceleration. The system described in

[36] .

[44] The optical fiber is ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF(ZBLAN) The system described in

[36] .

[45] each segment of optical fiber having a substantially uniform length of about 3 inches; The system described in

[36] .

[46] a distance between the first position and the second position is at least about 0.5 meters, and the annealing unit moves from the first position to the second position during the first acceleration in about 320 milliseconds. The system described in

[36] .

[47] The critical cooling rate is at least about 40 degrees Celsius (°C) per second; The system described in

[36] .

[48] The glass transition temperature is about 260° C., the crystallization temperature is about 352° C., and the melting temperature is about 450° C. The system described in

[36] .

[49] 1. A method for removing defects from a length of optical fiber, the length including a fiber core and a cladding surrounding the fiber core, the optical fiber being disposed at least partially within an annealing unit of a system including one or more processors, the method comprising: (a) using the one or more processors, securing a given segment of the optical fiber adjacent to a heating element of the annealing unit; (b) using the one or more processors and the heating element to heat the given segment to a crystallization temperature (T x ) higher than the melting temperature (T m ) to a first temperature less than (c) using the one or more processors, moving the annealing unit from a first position to a second position at a first acceleration; (d) maintaining the first temperature of the given segment for a first time period using the one or more processors and the heating element during the acceleration; (e) during a second time period, using the one or more processors, heating the given segment to a glass transition temperature (T g (c) cooling the optical fiber to a second temperature greater than the critical cooling rate of the optical fiber; (f) releasing the given fiber segment using the one or more processors after the second period of time; (g) using the one or more processors, moving the annealing unit from the second position to the first position at a second acceleration slower than the first acceleration; (h) repeating steps (a)-(g) using the one or more processors for each subsequent segment of the optical fiber until the entire length of the optical fiber has been processed; A method comprising:

[50] prior to step (f), determining, using the one or more processors, whether a given segment of the optical fiber meets a fiber loss threshold; if the threshold is not met, repeating steps (b)-(e) for the given segment using the one or more processors; The method according to

[49] , further comprising:

[51] Step (a) comprises securing the given segment to a clamping system of the annealing unit, and step (f) comprises releasing the given segment from the clamping system. The method described in

[49] .

[52] the second time period begins after the end of the first time period during the first acceleration. The method described in

[49] .

[53] each segment of optical fiber having a substantially uniform length of about 3 inches; The method described in

[49] .

[54] a distance between the first position and the second position is at least about 0.5 meters, and the annealing unit moves from the first position to the second position during the first acceleration in about 320 milliseconds. The method described in

[49] .

[55] The optical fiber is ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF(ZBLAN) The method described in

[49] .

[56] The critical cooling rate is at least about 40 degrees Celsius (°C) per second; The method described in

[49] .

[57] The glass transition temperature is about 260° C., the crystallization temperature is about 352° C., and the melting temperature is about 450° C. The method described in

[49] .

Claims

1. An optical fiber power supply system, comprising: a laser light source configured to emit high power laser energy; a photodetector configured to convert the detected light into electrical energy and provide the electrical energy to an electrical load; A fiber optic cable; A power control unit; The optical fiber cable comprises: a first end coupled to the laser light source; an opposing second end coupled to the photodetector; and a length extending between the first end and the second end; a plurality of optical fibers, each of the optical fibers extending individually along the length of the fiber optic cable; a thermal filler configured to surround each of the optical fibers and extend a length of the fiber optic cable; the power control unit is configured to control the output of the high power laser energy by adjusting the number of the optical fibers used to transmit the high power laser energy based on a power requirement of the electrical load. Optical fiber power supply system.

2. the laser light source includes one or more laser diode bars operating at a wavelength of about 2.1 μm; The optical fiber power supply system according to claim 1 .

3. the optical detector includes at least one photodiode detector; The optical fiber power supply system according to claim 1 .

4. Each optical fiber is made of ZrF 4 -BaF 2 -LaF 3 -AlF 3 - NaF(ZBLAN), The optical fiber power supply system according to claim 1 .

5. the fiber optic cable is capable of transmitting laser energy having a power of about 1 gigawatt over a distance of about 1000 kilometers (km) with a loss of about 0.1 decibels (dB); The optical fiber power supply system according to claim 1 .

6. an optical transmitter coupled to the second end of the fiber optic cable and configured to transmit a data signal; an optical receiver coupled to the first end of the fiber optic cable and configured to receive the data signal; The optical fiber power supply system of claim 1 , further comprising:

7. The method of claim 1, wherein the data signal includes information regarding the power requirements of the electrical load. The optical fiber power supply system according to claim 6 .

8. The power control unit is further configured to control an amount of power provided by the laser light source based on the data signal. The optical fiber power supply system according to claim 7 .

9. the power control unit is further configured to turn off the laser light source when the power requirement exceeds a threshold amount of power. The optical fiber power supply system according to claim 8 .

10. the power control unit is further configured to determine a number of the plurality of optical fibers necessary to meet the power requirement, and to deliver laser energy from the laser light source to the light detector using the number of optical fibers. The optical fiber power supply system according to claim 8 .

11. the power control unit is coupled to an external power source configured to provide power to the laser light source; The optical fiber power supply system according to claim 8 .

12. 1. A method of managing power delivery in a fiber optic power system, comprising: a transmitting unit having a laser light source; a receiving unit having a photodetector; and a fiber optic cable coupled between the transmitting unit and the receiving unit, the fiber optic cable including a plurality of optical fibers, each optical fiber extending a length of the fiber optic cable and surrounded by a thermal filler, the method comprising: transmitting high power laser energy from the transmitting unit to the receiving unit using a number of the optical fibers in the optical fiber cable; receiving at a processor a data signal transmitted from the receiving unit to the transmitting unit using the fiber optic cable, the data signal including information regarding power requirements of an electrical load coupled to the receiving unit; using the processor to control the high power laser energy output by the transmitting unit by adjusting a number of the optical fibers used to transmit the high power laser energy based on the power requirements of the electrical load; A method comprising:

13. and controlling the high power laser energy output by the transmitting unit further comprises interrupting transmission of the high power laser energy when the power requirements of the electrical load exceed a threshold amount of power associated with an external power source coupled to the transmitting unit. The method of claim 12.

14. and controlling the high power laser energy output by the transmitting unit further comprises adjusting an amount of power output by the laser light source according to the power requirements of the electrical load. The method of claim 12.

15. the data signal further includes information verifying power supply to the electrical load. The method of claim 12.

16. the data signal is an optical data signal generated by an optical transmitter included in the receiving unit and transmitted over the optical fiber cable, the step of receiving the data signal includes a step of receiving the optical data signal at an optical receiver included in the sending unit, and the method further includes a step of converting the optical data signal into a digital data signal. The method of claim 12.

17. Each optical fiber is surrounded by a thermal filler; The method of claim 12.

18. the optical detector includes at least one photodiode detector; The method of claim 12.

19. the fiber optic cable is capable of transmitting laser energy having a power of about 1 gigawatt over a distance of about 1000 kilometers (km) with a loss of about 0.1 decibels (dB); The method of claim 12.

20. the laser light source includes one or more laser diode bars operating at a wavelength of about 2.1 μm; The method of claim 12.

21. Each optical fiber is made of ZrF 4 -BaF 2 -LaF 3 -AlF 3 - NaF(ZBLAN), The method of claim 12.

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