Optical fiber cable, and system and method for distributing ultra-high power using optical fiber cable

Abstract

To provide an optical fiber cable and an integrated optical fiber power supply system capable of efficiently transmitting ultra-high power over long distances with significantly low loss.SOLUTION: Embodiments include 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 disposed radially around the cooling tube, each optical fiber comprising 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, wherein 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. Various systems and methods for removing defects from individual optical fibers and for distributing power over long distances using the optical fiber cable are also provided.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This disclosure relates to optical fibers in general, and more specifically to optical fiber cables, systems for distributing power using or otherwise using optical fiber cables, and techniques for refining optical fibers contained in such cables. [Background technology]

[0002] Fiber optic cables can be used to transmit power to endpoints located far from the power source. Typically, the term "power over fiber" refers to a system where power generated by a power source is converted into optical power using a laser light source, this optical power is transmitted via a fiber optic cable to a photodetector, which then converts the optical power back into 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 made 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 power systems, including little to no risk of electrical interference, power outages due to lightning, and explosions caused by electrical sparks. Furthermore, fiber optic cables have significantly higher power density, can withstand higher temperatures, and are much lighter than electrical cables. Unlike electric wires, the same optical fiber can be used to transmit optical power in one direction and return data in the other direction using, for example, different wavelengths or channels. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, conventional optical fiber power transmission systems utilizing silica-based fibers suffer from transmission and distribution losses, low conversion efficiencies at both the transmitting (i.e., electricity-to-optical) and receiving (i.e., optical-to-electrical) ends, and significant attenuation in the transmission medium itself, thus limiting the broad applicability of such systems. For example, high-power transmission over long distances (e.g., 800 kilometers (km) on an elevated structure or 50 km below sea level) is achieved using high-voltage direct current (HVDC) transmission systems (also known as power or electrical superhighways) that use copper or aluminum cables instead of silica-based fibers. Even then, the conversion efficiency from alternating current (AC) to HVDC is considered 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 superior infrared transmittance and a significantly lower loss profile than standard silica. For example, as shown in Figure 1, a standard silica fiber has a minimum loss of about 0.25 dB / km at 1550 nanometers (nm), while the theoretical loss limit of a ZBLAN fiber is three orders of magnitude lower, at about 0.0001 dB / km. However, this loss limit is often difficult to reach because ZBLAN often contains undesirable impurities or crystallites that may be formed during the manufacturing process and may hinder the transmittance of the material.

[0006] Specifically, as shown in Figure 2, ZBLAN is a glass transition temperature (i.e., T) at which the ZBLAN fiber transitions from a solid glass state to a liquid or viscous state. g ) and the temperature at which crystallization occurs (crystallization temperature T xThe temperature difference between the two is relatively small. As a result, the operating range of ZBLAN is narrow, and crystallites are relatively easily formed during the drawing process. It has been shown that growing ZBLAN in zero gravity or microgravity (i.e., outer space) rather than unit gravity (i.e., on Earth) can suppress or reduce crystallite formation due to the reduction of convection processes under microgravity conditions. However, conventional techniques for manufacturing ZBLAN under microgravity conditions are extremely costly, time-consuming, and / or difficult to implement on a large scale, for example, because they require transportation in space or the use of abandoned mine shafts on Earth.

[0007] Therefore, in this field, there is still a need for optical fiber cables and integrated optical fiber power supply systems that can efficiently transmit ultra-high power over long distances with significantly lower losses.

[0008] The present invention aims to solve the above-mentioned and other problems by providing a system, method, and apparatus configured to provide (1) an optical fiber cable comprising a plurality of individual ZBLAN fibers capable of transmitting ultra-high-power laser energy over long distances with significantly lower loss; (2) a technique for removing defects from the optical fiber, comprising annealing the fiber in a microgravity environment formed on Earth; and (3) an optical fiber power supply system comprising the optical fiber cable, an ultra-high-power laser light 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 fixed length of optical fiber, comprising a fiber core and a cladding surrounding the fiber core, wherein a given segment of the optical fiber is subjected to the crystallization temperature (T) of the fiber. x ) is higher than the fiber melting temperature (T mAn annealing unit including a heating chamber configured to heat internally to a first temperature lower than x ) and a heating chamber configured to move the annealing unit from a higher position to a lower position using free fall motion and further configured to maintain the first temperature of a segment of the optical fiber during a first period of the free fall motion, the annealing unit being, during a second period, at a second temperature lower than the crystallization temperature (T g ) of the optical fiber and higher than the glass transition temperature (T

[0010] cooling at a critical cooling rate associated with the optical fiber, and after the end of the second period, the annealing unit being further configured to transfer a subsequent segment of the optical fiber into the heating chamber, and the chamber being further configured to move the annealing unit from a lower position to a higher position, to provide a system. x ) and lower than the melting temperature (T m ) of the fiber, and (c) using one or more processors to move the annealing unit from a higher position to a lower position using free fall motion, and (d) during the free fall motion, using the heating chamber and one or more processors to maintain the given segment at the first temperature over a first period, and (e) during a second period, using one or more processors to maintain the given segment at a second temperature lower than the crystallization temperature (T x ) of the fiber and lower than the glass transition temperature (T gCooling at the critical cooling rate of the fiber to a second temperature higher than ; (f) after the second period, moving the annealing unit from a lower position to a higher position using one or more processors; (g) using one or more processors to repeat steps (a) - (f) for each subsequent segment of the optical fiber until the entire length of the optical fiber is processed. A method including these steps is provided.

[0011] Yet another exemplary embodiment is a system for reducing defects in a fixed - length optical fiber including a fiber core and a cladding surrounding the fiber core, the system comprising a heating element configured to selectively heat a given segment of the optical fiber to a first temperature higher than the crystallization temperature (T x ) of the fiber and lower than the melting temperature (T m ) of the fiber, a clamping system configured to selectively fix a given segment adjacent to the heating element, an annealing unit including the heating element and the clamping system, and an acceleration chamber configured to move the annealing unit and a given segment of the optical fiber fixed therein from a first position to a second position with a first acceleration and to move the annealing unit and the given segment from the second position to the first position with a second acceleration lower than the first acceleration, wherein a given segment of the optical fiber is heated by the heating element to the first temperature for a first period while at the first acceleration, the given segment is cooled at a critical cooling rate related to the fiber to a second temperature lower than the crystallization temperature of the fiber and higher than the glass transition temperature (T g ) of the fiber for a second period, and the clamping system is configured to release a given segment of the optical fiber after the second period and fix a subsequent segment of the optical fiber adjacent to the heating element. A system is provided.

[0012] Another exemplary embodiment is a method for removing defects from a fixed length of optical fiber, including a fiber core and cladding around the fiber core, at least partially located within an annealing unit of a system including one or more processors, comprising: (a) using one or more processors to fix a given segment of the optical fiber adjacent to a heating element of the annealing unit; and (b) using one or more processors and the heating element to bring the given segment to the crystallization temperature of the fiber (T x ) is higher than the fiber melting temperature (T m (c) heating to a first temperature lower than ); (d) moving the annealing unit from a first position to a second position with a first acceleration using one or more processors; (e) maintaining the first temperature of a given segment for a first period of time using one or more processors and a heating element while the first acceleration is at play; (c) during a second period of time using one or more processors to bring the given segment to a glass transition temperature (T) lower than the crystallization temperature of the fiber. g The present invention provides a method comprising: (f) cooling the fiber to a second temperature higher than ) at a critical cooling rate of the fiber; (g) releasing a given fiber segment after a second period using one or more processors; (h) moving an annealing unit from a second position to a first position at a second acceleration slower than the first acceleration using one or more processors; and (g) repeating steps (a) to (g) for each subsequent segment of the optical fiber until the entire length of the optical fiber has been processed using one or more processors.

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

[0014] Another exemplary embodiment is a method for managing power supply in an optical fiber power supply system comprising a transmission unit having a laser light source, a reception unit having a photodetector, and an optical fiber cable coupled between the transmission unit and the reception unit. The optical fiber cable includes a plurality of optical fibers, each optical fiber extending along the length of the optical fiber cable. The method includes transmitting high-power laser energy from the transmission unit to the reception unit using a certain number of optical fibers included in the optical fiber cable; receiving, in a processor, a data signal transmitted from the reception unit to the transmission unit using the optical fiber cable and including information regarding the power requirement of an electrical load coupled to the reception unit; and controlling the high-power laser energy output by the transmission unit by adjusting, using the processor, 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 is 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 disposed radially around the cooling tube, each 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, wherein 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.

[0016] To be understood, this disclosure is defined by the appended claims. This specification is a summary of embodiments and should not be used to limit the claims. Other embodiments are also conceivable in accordance with the art described herein, as will become apparent to those skilled in the art upon consideration of the following drawings and detailed description, and such embodiments are intended to be included within the scope of this application.

[0017] To better understand the present invention, embodiments shown in the following drawings may be referenced. To highlight and clearly illustrate the novel features described herein, components in the drawings are not necessarily to scale, relevant elements may be omitted, or in some cases, proportions may be exaggerated. Furthermore, as is known in the art, system components can be arranged in various ways. In addition, the same reference numerals throughout multiple drawings indicate corresponding parts. [Brief explanation of the drawing]

[0018] [Figure 1] This graph shows the known predicted loss profiles for silica and ZBLAN. [Figure 2] This graph shows known differential scanning calorimeter (DSC) results indicating the crystallization temperature and glass transition temperature of ZBLAN. [Figure 3] This is a functional block diagram showing an exemplary optical fiber power supply system, including the optical fiber cable shown in Figure 3, according to several embodiments. [Figure 4] This is a schematic diagram showing a cross-sectional view of an exemplary optical fiber cable according to several embodiments. [Figure 5] This graph shows acceleration profiles used to improve optical fibers in several embodiments. [Figure 6] This is a flowchart illustrating an exemplary method for removing defects from a fixed length of optical fiber, according to several embodiments. [Figure 7A] This is a functional block diagram of an exemplary improved system for reducing defects in optical fibers using the method shown in Figure 6, according to several embodiments. [Figure 7B] This is a functional block diagram of an exemplary annealing unit included in the improved system of Figure 7A, according to several embodiments. [Figure 8] This is a flowchart of another exemplary method for removing defects from a fixed length of optical fiber, according to several embodiments. [Figure 9] This is a schematic diagram of an exemplary improved system for removing defects in an optical fiber using the method shown in Figure 8, according to several embodiments. [Figure 10A] This is a schematic diagram showing a front perspective view of an exemplary annealing unit included in the improved system of Figure 9, according to several embodiments. [Figure 10B] This is a schematic diagram showing a bottom perspective view of an exemplary annealing unit included in the improved system of Figure 9, according to several embodiments. [Figure 10C] This is a schematic diagram showing a top view of an exemplary annealing unit included in the improved system of Figure 9, according to several embodiments. [Figure 11A] This is a schematic diagram of an exemplary clamping system for securing optical fibers within the improved system shown in Figure 9, according to several embodiments. [Figure 11B] This is a schematic diagram of an exemplary clamping system for securing optical fibers within the improved system shown in Figure 9, according to several embodiments. [Figure 12] This is a functional block diagram of another exemplary optical fiber power supply system according to several embodiments. [Figure 13] This is a functional block diagram of an exemplary optical power distribution system according to several embodiments. [Figure 14] This is a flowchart illustrating an exemplary power transmission management method in an optical fiber power supply system, according to several embodiments. [Figure 15]This is a functional block diagram of another exemplary fiber optic power supply system configured for medical applications, according to several embodiments. [Figure 16] This is a schematic diagram showing a cross-sectional view of an exemplary optical fiber included in the system of Figure 15, according to several embodiments. [Modes for carrying out the invention]

[0019] While the present invention can be embodied in various forms, this disclosure should be considered illustrative and not intended to limit the invention to any particular embodiment shown in the drawings. The drawings illustrate several exemplary and non-limiting embodiments, which are described below.

[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. Specifically, references to objects preceded by "the" or "a and an" are intended to refer to one of several possible such objects.

[0021] In the following description, elements, circuits, and functions are sometimes shown in block diagram form to avoid obscuring the disclosure with unnecessary detail. Furthermore, block designations and logic divisions between various blocks are illustrative of specific embodiments. In addition, those skilled in the art will understand that the information and signals shown in the block diagrams can be represented using various different one or more technologies. For example, while the diagrams may represent data, instructions, signals, or commands, these can also be understood to represent voltages, currents, electromagnetic waves, magnetic fields, or optical fields, or combinations thereof. Also, in some drawings, signals are represented as a single signal for clarity, but those skilled in the art will recognize that this signal can also represent a bus of multiple signals. Various exemplary logic blocks, modules, and circuits described in relation to the embodiments disclosed herein can be implemented or executed using one or more processors. As those skilled in the art will understand, the disclosure of separate processors in the block diagrams can indicate multiple processors performing the functions or logic sequences disclosed herein, or represent multiple functions or sequences performed on a single processor.

[0022] The systems, methods, and apparatus described herein provide techniques for improving ZBLAN fibers and for providing optical fiber cables composed of multiple strands of modified ZBLAN fibers that can transmit large amounts of power over very long distances with significantly lower loss. Furthermore, an optical fiber power supply system is provided that utilizes an optical fiber cable as a 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] Applications for fiber optic power supply systems are diverse, including optical power distribution systems and medical or surgical applications. Embodiments include optical power distribution systems that use fiber optic cables as interconnectors for intercontinental transmission of ultra-high-capacity optical power (e.g., enough to power a small country) under submarine or underwater conditions. For example, an optical power distribution system can distribute up to 1 gigawatt of power over distances of approximately 1000 km at sea level or 50 km underwater. Other embodiments provide optical power distribution systems that use fiber optic cables to distribute power between substations via a power grid and / or to power relay towers in residential and commercial environments in power over Ethernet (PoE) applications and / or to distribute power in various automotive and aerospace applications.

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

[0025] The light source 102 includes one or more laser diodes or other semiconductor devices capable of converting electrical energy into light energy and emitting light energy. In some embodiments, the light source 102 is part of a large-scale electrical-to-optical conversion unit, such as shown in Figure 12. In a preferred embodiment, the light source 102 is a high-efficiency laser light source capable of emitting ultra-high-power laser energy at an ultra-low threshold current. As an example, the light source 102 (also referred to herein as the “laser light source”) may 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 may be multi-emitter multimode 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 a plurality of laser diodes arranged in an array (e.g., a diode array). In such cases, each diode can be controlled individually (e.g., on or off) to change or control the total output power of the light source 102. The light source 102 may further include one or more monitor diodes configured to stabilize the output of the light source 102 (e.g., to 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 in the light source 102 and to supply these signals to a processor (e.g., the processor 730 in Figure 7).

[0026] The photodetector 106 includes a photodiode, photovoltaic cell, or other semiconductor device capable of detecting laser light or other light energy and converting the detected light into electrical energy. In some embodiments, the photodetector 106 is part of a large-scale photoelectric-to-electrical conversion unit, such as shown in Figure 12. In preferred embodiments, the photodetector 106 includes one or more high-efficiency photodiode detectors (e.g., 4-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), as well as a continuous power transmission of about 1 watt (W).

[0027] The optical fiber cable 104 can serve as a transmission medium for carrying optical power from the light source 102 to the photodetector 106. The optical fiber cable 104 can also be configured to transmit data signals in addition to optical power, as shown in Figure 13, for example. In a preferred embodiment, the optical fiber cable 104 is an ultra-high power cable comprising a plurality of bundled optical fibers, each having a cooled core and a thermal acrylic filler that extends along the length of the cable and surrounds each optical fiber containing ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN). In one embodiment, the optical fiber cable 104 transmits laser energy having at least about 1 gigawatt (GW) of power with a loss of about 0.1 decibels (dB) and 0.4 GW / cm². 2 It can transmit power at that power density over a distance of at least approximately 1,000 kilometers (km).

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

[0029] As shown in the figure, the optical fiber cable 200 includes a plurality of optical fibers 202 arranged radially around a central cooling tube 204 and enclosed by an outer protective cover 206. According to some embodiments, the optical fiber cable 200 may include any number of fibers 202 selected from a range of about 5 to 10 fibers depending on the desired power capacity and transmission distance. In one such embodiment, the optical fiber cable 200 includes a bundle of eight optical fibers 202, with a laser energy having at least about 1 gigawatt (GW) of power, a loss of about 0.1 decibels (dB), and 0.4 GW / cm². 2 This power density allows transmission over distances of at least approximately 1,000 kilometers (km). In other embodiments, the optical fiber cable 200 includes up to approximately 8,000 optical fibers 202 to meet ultra-high-capacity power transmission needs.

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

[0031] The cooling tube 204 is configured to increase the power capacity of the cable 200 by neutralizing or dissipating the heat generated by the optical fiber 202 during power transmission. For example, the cooling tube 204 can 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 the ZBLAN (e.g., approximately 315 degrees Celsius (°C)). In one embodiment, the cooling tube 204 is configured to maintain or keep the overall temperature of the cable 200 below 100°C. In other embodiments, the cooling tube 204 can be configured to maintain the cable temperature at or below different threshold temperatures.

[0032] According to the embodiments, the cooling tube 204 includes a hollow interior filled with a suitable coolant or refrigerant 208, such as air or other gases, or a suitable oil or other liquid. For example, the refrigerant 208 may include mineral oils or alkylates such as linear decylbenzene or branched nonylbenzene. In some embodiments, the refrigerant 208 is cryogenic air, and the two ends of the cooling tube 204 (e.g., at both ends of the cable 200) can be kept open to allow the cryogenic air to passively circulate throughout the tube 204. In other embodiments, the refrigerant 208 is cryogenic air or liquid that is actively pushed throughout the tube 204 using a refrigerant 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 may 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 the cable 200, the type of coolant 208, and the operating environment of the cable 200 (e.g., below sea level or underground).

[0033] The cooling tube 204 itself can be formed from aluminum, acrylic, or other suitable material. For example, if a thicker wall and / or higher mechanical stability is required (e.g., if the cable 200 contains many fibers 202 and therefore transmits a lot of power and generates a lot of heat), the cooling tube 204 can be made from aluminum. Alternatively, if a thinner wall is sufficient (e.g., if the cable 200 contains a small number of fibers 202 and therefore transmits little power and generates little heat), the cooling tube 204 can be made from acrylic. In embodiments where the cable 200 transmits a small amount of power, the diameter of the cooling tube 204 can be made very small, or the cooling tube 204 can be omitted entirely.

[0034] The outer protective cover 206 (also called a “protective jacket”) is made of polyurethane (PUR) or polyvinyl chloride (PVC) and is configured to protect and isolate the fiber 202 and cooling tube 204 from external physical forces and chemical degradation. The protective cover 206 also provides housing that encloses the internal components of the cable 200. In some embodiments, the outer protective cover 206 includes multiple material layers that are concentrically arranged and joined to each other to form the cover 206.

[0035] As shown in Figure 4, the optical fiber cable 200 further includes an inner thermal filler 210 positioned between the outer protective cover 206 and the central cooling tube 204, surrounding each of the optical fibers 202. In embodiments, 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 avoids the formation of hot spots if heat buildup is present in one or more of the fibers 202 by isolating the individual fibers 202 or preventing contact between them by completely surrounding each of the optical fibers 202. Furthermore, the thermal filler 210 may have a porous structure composed of multiple pores of different sizes to provide variable thermal insulation and structural integrity. As airflow passes through these pores, heat is transferred or moved throughout the filler 210, thus suppressing or preventing heat buildup around specific fibers 202. According to the embodiment, the thermal filler 210 can be made of acrylic (e.g., polymethyl methacrylate (PMMA)) or other suitable material.

[0036] The optical fiber cable 200 has a length (for example, length x as shown in Figure 3) extending between the first end and the second end, and each of the central cooling tube 204, outer protective cover 206, inner thermal filler 210, and multiple optical fibers 202 extends to the length of this cable 200. Thus, each of the optical fibers 202 can extend substantially parallel to the central cooling tube 204, and the outer protective cover 206 can be aligned concentrically with the cooling tube 204.

[0037] According to the embodiment, each optical fiber 202 is a multimode fiber having a fiber core 212 and a cladding 214 arranged around the fiber core 212. The fiber core 212 can be positioned in the center of the cladding 214 and fused or joined to the cladding 214. The core 212 may be a step-index fiber core containing a 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 embodiment example, the core diameter is about 600 μm.

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

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

[0040] The ZBLAN optical fiber 202 is improved or modified using one or more annealing methods, such as method 300 shown in Figure 6 and / or method 500 shown in Figure 8, before the manufacture of the optical fiber cable 200. These methods are configured to optimize the fiber 202 for longer transmission by removing or reducing defects that cause scattering loss in the core and cladding of the ZBLAN. Furthermore, while conventional methods for improving a considerable amount of ZBLAN fiber require travel to space (e.g., LEO satellites or the International Space Station) to obtain the necessary low-gravity or microgravity environment, the annealing methods described herein can be achieved without leaving Earth or using aircraft.

[0041] Generally, these methods involve processing a ready-made ZBLAN fiber, such as optical fiber 202 shown in Figure 4, in very short segments to remove crystals and other defects within the fiber, and thus improving the ready-made fiber. According to embodiments, this process reduces the glass transition temperature (T) of the ZBLAN. g ) is sufficiently higher than the crystallization temperature (T x ) is higher than the melting temperature (T m This includes heating the fiber to a temperature lower than 260 degrees Celsius (T). For example, if the ZBLAN fiber is heated to about 260 degrees Celsius (°C). g And, T at approximately 352℃ x And, T at approximately 450℃ m In embodiments having the above, the ZBLAN fiber is annealed at a temperature of approximately 370°C (T) during this process. aThe process involves heating the ZBLAN fiber to the annealing temperature while simultaneously applying the Earth's gravitational acceleration (e.g., 9.8 meters per second squared (m / s²)) over a predetermined period of time to simulate a free-fall or microgravity environment. 2 This further includes accelerating to a quenching temperature (T) below the crystallization temperature. q This includes rapidly cooling or quenching the fiber to annealing temperature. 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 may be about 350°C. To help avoid the introduction of new crystallites during this process, the cooling step is started while the fiber is still in a state of free fall, and thus ensures that the annealing step is completed before gravity becomes present.

[0042] The process of perfecting ZBLAN fibers can be monitored in-situ using a combination of lasers and photodetectors, or other devices that can measure the fiber's scattering profile or the amount of incident light scattered by defects in the material in real time. The scattering profile indicates the crystallite percentage 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 percentage, the process can be repeated through multiple cycles until the optimal fiber loss index is achieved.

[0043] Figure 5 shows an exemplary acceleration profile 250 of a ZBLAN fiber during processing as described herein, according to an embodiment. As shown in the figure, the acceleration profile 250 changes over three periods. During the first period t1, the fiber accelerates from zero (a=0) to approximately 9.8 m / s². 2 Standard free fall acceleration or gravity (g) equal to o The fiber is accelerated by the acceleration due to ). Also, during this first period, the fiber moves from the starting temperature to the annealing temperature T aThe fiber is heated to (for example, 370°C). This first period t1 can also be called the "ramp-up" period. During the second period t2, the fiber continues to move due to gravitational acceleration. Also during the second period, the fiber continues to be heated to the annealing temperature or held at the annealing temperature for a predetermined time length. During the third period t3, the fiber decelerates and returns to a stationary state. Also during the third period, the fiber is rapidly cooled to a predetermined temperature T for a predetermined time length. q It is cooled.

[0044] In the embodiment, the second period t2 includes a first predetermined time length for heating the fiber and a second predetermined time length for cooling the fiber. The first time length can be considered the fiber annealing period, as it includes the period during which the fiber is annealed or heated to the annealing temperature. The second time length constitutes part of the fiber cooling period. This cooling period also includes at least part of a third period t3, i.e., at least part of a predetermined time length required to cool the fiber to the quenching temperature. According to the embodiment, the second time length is located at the end of the second period t2 so that the cooling period begins during acceleration. This ensures that the fiber is still in a state of 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 time length is longer than the second time length. In some embodiments, the length of the annealing period and the length of the cooling period are substantially equal.

[0045] The exact duration of each of the three periods (t1, t2, and t3) can be determined based on several factors. For example, the first period may depend on the acceleration rate of the fiber and the heating rate of the element used to heat the fiber. The second period may depend on the distance the fiber travels during acceleration (e.g., descent due to free fall), in addition to the free-fall acceleration, and the length of the fiber to be annealed. The third period may 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 cases, a second period of approximately 320 milliseconds (ms) is considered necessary for a fiber length of approximately 1 meter, while the first and third periods are much shorter (e.g., 100 ms). Figure 5 shows periods t1 and t3 as being approximately equal, but in other cases, these two periods may vary or differ from each other depending on the factors described above, for example.

[0046] In some embodiments, the acceleration rate or speed at which the fiber accelerates during the first period can be determined based on several 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 a mechanism (e.g., an actuator) used to put the fiber into free fall or otherwise release the fiber into a gravitational field. Similarly, the deceleration rate or speed at which the fiber decelerates during the second period can be determined based on the same fiber properties and a mechanism (e.g., a gripper or brake) used to slow the fiber's motion by applying frictional force.

[0047] Figure 6 shows a first exemplary process or method 300 for removing defects from a fixed length of optical fiber, including a fiber core and cladding around the fiber core. In embodiments, the optical fiber may be the same as or substantially similar to the optical fiber 202 shown in Figure 4. Figure 7A shows an exemplary fiber refining system 400 configured to remove defects from a fixed length of ZBLAN fiber. In some embodiments, process 300 can be performed using system 400. Therefore, in the following paragraphs, process 300 will be described in relation to system 400 for ease of explanation. However, it should be understood that in other embodiments, process 300 can also be performed using other systems or devices capable of annealing ZBLAN fibers.

[0048] Referring first to Figure 7A, according to one embodiment, the fiber refurbishing system 400 includes a chamber or tower 402 (also called a “fall tower”) and one or more annealing units 404 configured to be movably positioned within the tower 402 and to process a given segment of optical fiber 406. The tower 402 may be configured to mimic a microgravity environment by placing each annealing unit 404 in a state of free fall for a predetermined period of time (e.g., the second period shown in Figure 5). In one embodiment, the tower 402 is about 44 meters high and is configured to provide a state of free fall for at least 3 seconds to process a segment of optical fiber 406 about 10 meters long. Figure 7A shows the tower 402 including annealing units 404a and 404b, but it should be understood that in other embodiments, the tower 402 may include only one or more than two annealing units 404. In some embodiments, the fiber improvement system 400 further includes one or more processors configured to communicate with the tower 402, one or more annealing units 404 and / or various other components of the system 400, to perform process 300 to improve the optical fiber 406 in accordance with the techniques described herein, or to otherwise control the components of the system 400.

[0049] Figure 7B shows an exemplary annealing unit 404 according to an embodiment. As shown, the optical fiber 406 is located within the annealing unit 404 and is configured to be subject to free fall or gravitational acceleration when the unit 404 falls or is released within the tower 402. The optical fiber 406 includes a ZBLAN fiber core and cladding arranged around the fiber core and can be substantially the same as or identical to the optical fiber 202 shown in Figure 4. Although Figure 7B shows the optical fiber 406 fully housed within the annealing unit 404, in other embodiments the annealing unit may be configured such that a portion of the optical fiber is housed within it and the remainder is located outside the annealing unit.

[0050] Referring again to Figure 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 high place to a low place in free fall motion, as shown, for example, by annealing unit 404a. The movable component 407 may be further configured to return the annealing units 404 from the low place to the high place, as shown, for example, by annealing unit 404b. According to embodiments, the distance h between the high place and the low place 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 Figure 6). In some embodiments, the distance h is selected to allow the completion of multiple annealing cycles within a single fall. The time (in milliseconds) required for the free-fall period in each cycle (e.g., the second period t2), as well as the lengths of the acceleration (or rise-up) and deceleration periods (e.g., the first and third periods t1 and t3), can be calculated using the acceleration profile 250 shown in Figure 5. The acceleration profile 250 can also determine the length of fiber that can be processed in one cycle. In one exemplary embodiment, the distance h is approximately 44 meters (m), the annealing unit 404 takes approximately 3 seconds to travel this distance, and the annealing unit 404 is configured to process approximately 10 meters of fiber within this time (e.g., 10 m / cycle).

[0051] In some embodiments, the movable component 407 includes a pulley system comprising one or more pulleys 408 and one or more cables 410 slidably coupled to the (single or double) pulleys 408. Each cable 410 can be slidably coupled to at least one annealing unit 404, and the pulley system 407 can be configured to transport and support the unit 404 as it moves from a high place to a low place and then back to a high place.

[0052] For example, in the illustrated embodiment, the pulley system 407 includes a first pulley 408a positioned at or adjacent to a high point, and a second pulley 408b positioned at or adjacent to a low point. As shown in the illustration, 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 for moving the annealing unit 404 from a high point to a low point, and a second direction for returning the annealing unit 404 from a low point to a high point. The pulley system 407 can be configured to place the annealing unit 404 in a free-fall state as it slides downward along the cable 410 toward the low point. For example, the cable 410 can be configured to impart zero or minimal friction to the annealing unit 404 as it moves toward the low point. Upon reaching the lower position, pulleys 408a and 408b both rotate in a second direction, allowing the cable 410 and the annealing unit 404 attached to the cable 410 to be pulled back to the higher position along the same path.

[0053] In other embodiments, the pulley system 407 may include multiple independent pulley systems, each coupled to a separate annealing unit 404. In such cases, these annealing units 404 can be dropped individually from a high place to a low place on separate cables and pulled back to the high place individually using separate pulleys. Other configurations of the movable component 407 may include, for example, a lift system configured to drop an annealing unit from a high place onto a platform located at a low place and then raise the platform and the annealing unit back to the high place.

[0054] In the embodiment, the tower 402 further includes a brake system 411 configured to be coupled to a movable component 407 and to control the movement of the movable component 407 and / or the 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 configured to stop the free-fall acceleration of the annealing unit 404 by stopping the rotation of the (single or double) pulleys 408 in a first direction, or by otherwise preventing the movement of the cable 410 between the first pulley 408a and the second pulley 408b. As an example, the brake system 411 may include one or more brakes (not shown) coupled to the cable 410 and / or one or more pulleys 408 and configured to activate these brakes when a stopping operation is desired. In some cases, a brake system 411 can be used to stop the annealing unit 404 at a low position when it is moving in a first direction, and at a high position when it is moving in a second direction. In some embodiments, the brake system 411 is further configured to initiate the free fall movement of the annealing unit 404 by releasing the brake so that the pulley 408 rotates in the first direction and / or the cable 410 moves freely in a different manner toward the lower position.

[0055] As shown in Figure 7B, each annealing unit 404 includes a heating chamber 412 for heating an optical fiber 406, or specifically, a given segment 406a of an optical fiber 406 placed in the chamber 412. The annealing unit 404 further includes one or more components for supplying 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 the length of the unmodified or pre-annealed optical fiber 406 and supply 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 the length of the modified or post-annealed optical fiber 406, including the modified segment of the optical fiber 406 as it exits the heating chamber 412. Therefore, the entire length of the optical fiber 406 can initially be stored on the first spool 414, and this length can be gradually transferred to the second spool 416 as the system 400 processes more and more optical fibers 406. 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 the embodiment, each segment 406a received in the heating chamber 412 may have a substantially uniform length, such as 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 Figure 7A) and / or the physical constraints of the annealing unit 404.

[0056] According to the embodiment, the heating chamber 412, as part of a process to remove defects from the optical fiber 406, heats a given segment 406a of the optical fiber 406 to the crystallization temperature (T) of the fiber core. x ) is higher than the glass transition temperature (T) of the fiber core. g ) is much higher, but the melting temperature of the fiber (T mIt is configured to be heated to a first temperature lower than ). Thus, the first temperature can be high enough to remove the crystals in the fiber core and cladding, but low enough to avoid completely melting the glass. In one embodiment, the 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. Therefore, the first temperature can be any value between 352°C and 450°C. In one embodiment, the first temperature is about 370°C.

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

[0058] In the 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 may include a ceramic or metal heating element that can be set to a desired temperature using an input value. In one embodiment, the heating element has a specific heat capacity of about 0.888 J / g·°C, which ensures 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 a 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 raise or lower 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 an independent processor that controls the operation of these heating elements and thermocouples. In other embodiments, the heating chamber 412 is electrically coupled to a processor 418 of the annealing unit 404, and the processor 418 is configured to manage the heating function of the heating chamber 412. In yet another embodiment, 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, as the next step in the defect removal process, heats the segment 406a to a crystallization temperature (T x ) is lower than the glass transition temperature (T g The annealing unit 404 can be further configured to rapidly cool or quench to a second temperature higher than the first temperature. In one embodiment, the second temperature is about 350°C, or about 10°C to 20°C lower than the first temperature. The annealing unit 404 can also be configured to cool the heated segment 406a at a critical cooling rate related to the optical fiber, which determines how long the cooling process takes (i.e., the cooling period). In an embodiment, the critical cooling rate for the ZBLAN fiber is 40°C / s. In such an example, it takes about 2 seconds to cool a fiber segment 406a that is about 10 meters long.

[0062] In some embodiments, the fiber segment 406a can be cooled when it exits the heating chamber 412. For example, the second spool 416 can be configured to draw a given segment 406a of the optical fiber 406 out of the heating chamber 412 at a speed or rate selected based on the critical cooling rate and the ambient temperature of the annealing unit 404, such that the heated segment 406a cools to a second temperature when it reaches the second spool 416. In other embodiments, a given fiber segment 406a can be cooled to a second temperature within the heating chamber 412. For example, the temperature of the heating chamber 412 can be rapidly reduced to a second temperature in order to rapidly cool the heated segment 406a. In such cases, the heating element can be reduced to a second temperature, for example, by reducing or removing the amount of current supplied 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, for example, according to process 300 in Figure 6. In other embodiments, 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, the processor 418 is electrically coupled to the heating chamber 412 to control the temperature setting of the heating element within the chamber 412. For example, the processor 418 can raise the temperature setting to a first temperature during annealing. The processor 418 can also be configured to raise or lower the temperature setting based on temperature readings received from the heating chamber 412 or a sensor (e.g., a thermocouple) located inside it.

[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 rotational speed and direction of rotation of the spools. For example, the processor 418 may 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 may also be configured to rotate the first spool 414 in a second direction opposite to the first direction to reverse the direction of movement of the optical fiber 406, for example, when a given segment 406a must be returned to the heating chamber 412 for further processing.

[0066] Furthermore, the processor 418 can be configured to control the speed at which the first and / or second spools 414 and 416 rotate, and thus control the speed or rate at which the optical fibers 406 enter and exit the heating chamber 412. In some embodiments, the rotation speed of the second spool 416 is selected so that when the heated segment 406a exits the chamber 412, the segment 406a cools rapidly to a second temperature at a critical cooling rate related to 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 can be configured to rotate at a speed or rate of 1 revolution per second to supply 1 meter of fiber (or one fiber segment 406a) per second to the heating chamber 412. In such embodiments, the annealing unit 404 can be configured to process 1 meter of fiber per second. As understood, the rotation speed can be adjusted as needed to accommodate larger (e.g., 10-meter long) fiber segments.

[0067] In various embodiments, the annealing unit 404 performs a post-annealing analysis of a given segment 406a to determine whether further processing is required to obtain optimal results. Specifically, the annealing unit 404 further includes one or more lasers or other sensors that monitor or measure the scattering profile of segment 406a after the cooling step is completed. The measurement information can be provided to a processor 418 for real-time analysis. The processor 418 can be configured to determine the fiber loss value of the annealed segment 406a based on the measurement information and compare this measurement with a fiber loss threshold stored in memory. If the threshold is not met, the processor 418 can be configured to return segment 406a to the heating chamber 412 for further processing, for example, by rotating a second spool 416 in a second direction (e.g., clockwise) to move the given segment 406a in the reverse 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 has left the heating chamber 412 or while it is still inside the chamber 412, depending on where the cooling process takes place. The laser can be appropriately positioned within the heating chamber 412 or at another location in the annealing unit 404. The annealing unit 404 may also include a photodetector, which is positioned opposite the laser so that the fiber segment 406a passes between the laser and the photodetector, or across a line of sight established between these 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 detected laser power or amount of laser light. 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 can pass straight through the fiber glass.

[0069] The processor 418 can be electrically coupled to the photodetector and configured to compare the photodetector output with a threshold or predicted current. If the measured quantity is too low, the processor 418 can return the fiber segment 406a to the heating chamber 412 for further processing. In some embodiments, the annealing and cooling process can be repeated until an optimal scattering coefficient or other fiber loss metric (e.g., 0.1 decibels per kilometer (dB / km) at 650 nm) is achieved for a given optical wavelength.

[0070] Next, referring again to Figure 6, process 300 will be described with reference to the components of system 400. In embodiments, process 300 can be carried out using one or more processors of system 400, including, for example, processor 418. As shown in the figure, process 300 begins in block 302 and places or positions a given segment of an optical fiber (e.g., fiber segment 406a) in the heating chamber (e.g., heating chamber 412) of an annealing unit (e.g., annealing unit 404) for processing or improvement. The fiber segment can be moved into the heating chamber by rotating the spool (e.g., spool 414) that holds the fiber before annealing toward the heating chamber in a first direction. In block 304, the fiber segment is subjected to the crystallization temperature (T) of the optical fiber. x ) is higher than the melting temperature of the fiber (T m Heat to a first temperature lower than ). 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 within the annealing unit is subjected to the Earth's gravitational acceleration (e.g., 9.8 m / s²). 2The annealing unit is dropped or moved from a high place to a low place using free-fall motion to accelerate it. 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 during this free-fall motion. (In this specification, this first period is also referred to as the “annealing period.”)

[0072] In block 310, the fiber segment is cooled to a second temperature over a second period (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 The temperature can be above ). In one embodiment, the second temperature is about 350°C, or about 10°C to 20°C lower than the first temperature. When the second period ends, the first processing cycle can be considered complete.

[0073] According to the embodiments, the second period may 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 (for example, within the third period t3 in Figure 5). Thus, the time allocated for free fall can be spent on heating and, at least partially, cooling the fiber segment. In some embodiments, the first period is substantially equal to the second period. In other embodiments, the second period may be longer than the first period. As understood, the exact length of the first period may be determined based on the physical length of the fiber segment and other factors described herein.

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

[0075] In block 316, one or more processors determine whether there are any subsequent fiber segments remaining in the fiber spool before annealing (e.g., the first spool 414). If the determination in block 316 is "no", process 300 terminates. If the determination in block 316 is "yes", process 300 returns to block 302 and begins processing the next fiber segment. Thus, process 300 can be repeated indefinitely until the entire length of the fiber before annealing is sufficiently improved or until the target fiber loss threshold (e.g., less than 0.1 dB / km at 650 nm) is met.

[0076] Figure 8 shows a second exemplary method or process 500 according to an embodiment for removing defects from a fixed length of optical fiber including a fiber core and surrounding cladding. For example, this optical fiber may be identical or similar to the optical fiber 202 shown in Figure 4. Figure 9 shows another exemplary fiber refining system 600 configured to remove defects in a fixed length of ZBLAN fiber. In some embodiments, process 500 can be performed using system 600. Therefore, in the following paragraphs, process 500 will be described in relation to system 600 for ease of explanation. However, it should be understood that in other embodiments, process 500 can also be performed using other systems or devices capable of annealing ZBLAN fibers.

[0077] Referring first to Figure 9, according to one embodiment, the fiber refurbishing system 600 includes an acceleration chamber 602 and an annealing unit 604 configured to be movably positioned within the chamber 602 and to process an optical fiber 606 of a given length. The optical fiber 606 includes a ZBLAN fiber core and cladding arranged around the fiber core, and is substantially the same as or identical to the optical fiber 202 shown in Figure 4. The acceleration chamber 602 can be configured to mimic a microgravity environment by placing the annealing unit 604 (also called the “spindle”) in a state of free fall for a predetermined time (e.g., a second period t2 shown in Figure 5). In one embodiment, the acceleration chamber 602 is about 0.5 meters high and is configured to provide about 320 milliseconds of free fall to process a segment of optical fiber 606 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 arranged adjacent to each other within the central opening, as will be described in more detail herein with reference to Figure 11. In embodiments, the clamping system 608 may 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 may be configured to release the processed segment 606a once it has been sufficiently processed (annealed and quenched) and to grip a new or subsequent segment of the optical fiber for processing. This release and gripping operation can be performed at any appropriate time or at any appropriate position in the acceleration chamber 602, such as when the annealing unit 604 returns to the highest or starting position of the acceleration chamber 602, after the annealing unit 604 has reached the highest position, or while the annealing unit 604 is still at the lowest position in the chamber 602. In this way, the optical fiber 606 can be processed segment by segment using the fall and free fall acceleration of the annealing unit 604.

[0079] As shown in the figure, the system 600 further includes a first spool 614 configured to hold or store the length of the optical fiber 606 before annealing, and a second spool 616 configured to hold or store the length of the optical fiber 606 after annealing. As will be 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 an acceleration chamber 602, an annealing unit 604, a heating chamber 612, a clamping system 608, and / or spools 614, 616. In some embodiments, one or more processors 618 are configured to perform the process 500 shown in Figure 8 to improve the optical fiber 606 according to the techniques described herein, or to control components of the system 600 in a different manner.

[0080] As shown in the figure, the first spool 614 can be positioned adjacent to the inlet of the acceleration chamber 602, and the second spool 616 can be positioned adjacent to the outlet of the acceleration chamber 602. During operation, the first spool 614 can be rotated in a first direction so that the optical fiber 606 can move from the first spool 614 to the second spool 616 through the acceleration chamber 602 after processing. As shown in the figure, the fiber 606 passes through the entire chamber 602, which contains the annealing unit 604 and the heating chamber 612. In some cases, for example, if a segment of the fiber 606 needs to be reprocessed or further improved as described herein, 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.

[0081] Referring further to Figures 10A to 10C, the annealing unit 604 has a generally annular outer wall 619 extending between the upper end 615 and the lower end 617 of the unit 604, and an open center 620 configured to house 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 may be longer or shorter, for example, depending 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 may be coupled to at least one of the opening upper end 615, the opening 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 the optical fiber 606 passes through the annealing unit 604. The hollow interior 613 can be defined by an upper opening that receives the fiber segment into the chamber 612 and a lower opening from which 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 placed within the heating chamber 612. For example, in some embodiments, the heating element can be arranged in a ring such that its walls 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 embodiment, the heating element is configured to have a specific heat capacity of about 0.888 J / g·°C to ensure a rapid temperature change of the heating element. The heating chamber 612, like the heating chamber 412 in Figure 7B, can be configured to heat a given segment of the optical fiber 606 to a first temperature higher than the crystallization temperature of the optical fiber 606 and lower than the melting temperature of the fiber 606. 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 that extend from the upper end 615 of the opening to the lower end 617 of the opening, distributed substantially evenly along the entire circumference of the wall 619, giving the annealing unit 604 a basket-like appearance as shown in Figures 10A–10C. (For ease of explanation, Figure 9 shows the outer wall 619 with a plane.) The exact width of each opening 622 can depend on the circumference of the outer wall 619, the desired number of openings 622, or the desired solid-to-space ratio of the outer wall 619. In some embodiments, the heating chamber 612 may also have a partially open (or non-solid) structure. The opening walls of the annealing unit 604 and / or the heating chamber 612 may be configured to allow airflow 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 a period, the heating chamber 612 can be configured to turn off its heating element so that a given fiber segment 606a is no longer heated to a first temperature. In some embodiments, the air passing through the opening 622 of the annealing unit 604 and / or the heating chamber 612 while the annealing unit 604 continues to free-fall may be sufficient to rapidly cool the fiber segment 606a to a second temperature that is lower than the crystallization temperature but higher than the glass transition temperature. For example, the second temperature may be about 350°C, or about 10°C to 20°C lower than the first temperature. In other embodiments, the annealing unit 604 may be configured to allow a suitable gas or liquid to flow through the opening wall of the annealing unit 604 and / or the heating chamber 612 for such rapid cooling purposes.

[0085] Figures 11A and 11B are partial enlarged views of the interior of the annealing unit 604 with the walls of the annealing unit 604 and heating chamber 612 removed to better illustrate the exemplary clamping system 608. As shown, the clamping system 608 includes two movable components 624 positioned opposite each other (or on both sides 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 are configured to move between a non-operating position shown in Figure 11A and an operating position shown in Figure 11B. Also as shown, the two movable components 624 are positioned adjacent to a fiber segment 606a located within the heating chamber 612 and are configured to engage with or compress both sides of the fiber segment 606a when in the operating position, and to keep the fiber segment 606a non-contact when in the non-operating position.

[0086] According to the embodiment, each movable component 624 (also called “actuator”) includes a gripping portion 626 that engages with the fiber segment 606a when moved to the operating 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 may be configured to apply sufficient frictional force to the fiber segment 606a to maintain or hold the segment 606a within the heating chamber 612 while the clamping system 608 is operating. For example, in some cases, the first spool 614 and / or the second spool 616 can apply sufficient downward force to the optical fiber 606 to continuously pull the fiber 606 toward the second spool 616. In such cases, the gripping portion 626 must be configured to counteract this downward force, for example, by applying a sufficient frictional force as a whole to overcome the downward force, or by otherwise preventing the fiber 606 from moving or sliding toward the second spool 616. In this way, a given fiber segment 606a can be fixed (or captured) within the heating chamber 612 so that it can be processed while in the operating position.

[0087] In contrast, when the clamping system 608 is in a non-operating or resting position, the components 624 are positioned substantially parallel to each other and to the fiber 606, such that the gripping portion 626 is positioned a certain distance away from the fiber segment 606a to avoid contact with the fiber segment 606a. In such a resting 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 called a “gripper” or “stopper”) is positioned at or near the lower end of each movable component 624. For example, in Figure 11A, the component 624 terminates at the gripping portion 626. In such cases, the operating position can be achieved by pressing or moving the lower end of each component 624 inward, for example, as shown in Figure 11B. In other embodiments, the gripping portion 626 may be positioned at or near the upper end of each movable component 624, in which case the gripping portion 626 can be activated by pressing the upper end of each component 624 inward. Other types of devices are also conceivable that grip segments of the optical fiber 606 during processing to hold the fiber segments within the heating chamber 612.

[0089] In one 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 subsequent segment of the fiber 606. For example, if the heating chamber 612 is configured to process 3 inches of fiber at a time, the clamping system 608 can be configured to grip or clamp the fiber 606 at 3-inch intervals. In this way, the entire length of the optical fiber 606 can be carefully processed or improved using the system 600.

[0090] In some embodiments, the processor 618 can 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 of the spools, including their rotational speed and direction, similar to the processor control of the spools 414 and 416. In some embodiments, the processor 618 can be electrically coupled to the clamping system 608 to control the movement of the movable component 624 between an operating position and a non-operating position.

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

[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 start of a processing cycle or at the upper end of the chamber 602, and the deceleration and stopping of the annealing unit 604 at the end of a cycle or when it reaches the lower end of the chamber 602. For example, the acceleration chamber 602 may 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 cases, 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 in 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 conceivable.

[0093] In some embodiments, the system 600 further includes one or more components that perform a post-annealing analysis of the processed segment 606a to determine whether 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. Furthermore, 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 the cooling process is complete) and to determine the fiber loss value of the processed segment 606a in real time based on the measurement information. The processor 618 compares the determined fiber loss value to a fiber loss threshold, and if the threshold is not met, the fiber segment 606a can be returned to the acceleration chamber 602 for further processing. In one embodiment, the processor 618 may repeat the annealing and cooling process until an optimal scattering coefficient or other fiber loss metric (e.g., 0.1 decibels per kilometer (dB / km) at approximately 650 nm) is achieved for a given optical wavelength.

[0094] Next, referring again to Figure 8, process 500 will be described with reference to the components of system 600. Process 500 can be performed using one or more processors included in system 600, for example, processor 618. As shown in the figure, process 500 starts from block 502 and fixes a fiber optic segment (e.g., fiber segment 606a) into an annealing unit (e.g., annealing unit 604). Specifically, a clamping system (e.g., clamping system 608) positioned adjacent to the heating chamber can be used to fix the fiber segment into the heating chamber of the annealing unit (e.g., heating chamber 612) or adjacent to the heating element of this heating chamber. The clamping system can be configured to fix or grip fiber segments of uniform length (e.g., 3 inches) for each processing cycle (e.g., annealing and cooling). In block 504, the fiber segment is fixed to the crystallization temperature (T) of the fiber optic. x ) is higher than the melting temperature of the fiber (T m Heat to a first temperature lower than ). 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 moves from a first position or starting position in the acceleration chamber (e.g., acceleration chamber 602) to a second position or ending position in the same chamber under gravitational acceleration (e.g., 9.8 m / s²). 2 ) or free-fall motion is used to drop or move the fiber segment. In the embodiment, the acceleration chamber 602 is configured to maintain free-fall motion for a minimum time (e.g., 320 milliseconds). In block 508, the temperature of the fiber segment is maintained at a first temperature for a first period during this free-fall motion. In block 510, the fiber segment is cooled to a second temperature for a second period. The second temperature is the crystallization temperature (T x ) is below the glass transition temperature (T gThe temperature can be above the first temperature. In one embodiment, the second temperature is about 350°C, or about 10°C to 20°C lower than the first temperature. When the second period ends, the fiber processing cycle can be considered complete.

[0096] According to the embodiments, the second period (also referred to herein as the “cooling period”) begins while the fiber segment is in free fall motion but can end after the free fall motion has stopped or while the fiber segment is decelerating (e.g., within the third period t3 in Figure 5). Thus, the time allocated for free fall can be spent on heating and, at least partially, cooling the fiber segment. In some embodiments, the first and second periods may be substantially equal in length. In other embodiments, the second period may be longer than the first period. As will be understood, the exact length of the first period depends on the physical length of the fiber segment and other factors described herein.

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

[0098] In block 516, one or more processors determine whether there are any subsequent fiber segments remaining in the fiber spool before annealing (e.g., the first spool 614). If the determination in block 516 is "no", process 500 terminates. If the determination in block 516 is "yes", process 500 proceeds to block 518 and releases the processed fiber segments from the heating chamber of the annealing unit. For example, one or more processors may cause the clamping system to release the grip on the fiber or transition to a non-operating state. Process 500 returns from block 518 to block 502 and begins processing the next fiber segment. Thus, process 500 can be repeated any number of times until the entire length of the fiber before annealing is sufficiently improved or until the target fiber loss threshold (e.g., less than 0.1 dB / km at 650 nm) is met.

[0099] In the embodiment, each of processes 300 and 500 can be at least partially implemented by at least one data processor that executes software stored in memory, such as a processor 418, and memory (not shown) included in the annealing unit 404 shown in Figure 7B, or by a processor 618 and memory (not shown) included in the acceleration chamber 602 shown in Figure 9. The processors 418 / 618 can each interact with one or more other components of the system 400 / 600 to perform the operation of a given process 300 / 500. The processors 418 / 618 can be any suitable hardware device that executes software instructions retrieved from memory, such as 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 memory, which can be any suitable memory device suitable for storing software instructions, such as volatile memory elements (e.g., random access memory (RAM such as DRAM, SRAM, SDRAM, etc.)), non-volatile memory elements (e.g., ROM, hard drives, tapes, and CD-ROMs, etc.), or any combination thereof. Furthermore, the memory may incorporate electronic storage media, magnetic storage media, optical storage media, and / or other types of storage media. In some embodiments, the memory includes a non-temporary computer-readable medium that implements all or part of one or more of the methods described herein and shown in Figures 5 and 8. The memory may store one or more executable computer programs or software modules containing instruction sets to be executed, such as 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 may be executed as software, firmware, hardware, or a combination thereof.

[0101] Figure 12 shows an exemplary optical fiber power supply system 700 according to an embodiment. The components of system 700 can be similar to those of the optical fiber power supply system 100 shown in Figure 3. For example, system 700 includes a light source 702 substantially similar to the light source 102 in Figure 3, an optical fiber cable 704 substantially similar to the optical fiber cable 104 in Figure 3, and a photodetector 706 substantially similar to the photodetector 106 in Figure 3. In some embodiments, the optical fiber cable 704 may have, like cable 104, a first end 708 coupled to the light source 702, a second end 710 coupled to the photodetector 706, and multiple optical fibers substantially similar to, for example, the ZBLAN optical fiber 202 shown in Figure 4, extending along the length of cable 704, i.e., the total length between the first end 708 and the second end 710. For brevity, the photodetector 706, the light source 702 (also called the “laser light source”), and the optical fiber cable 704 will not be described in detail here in light of their similarities.

[0102] In this embodiment, the optical fiber power supply system 700 can be used within or included in an optical fiber network that supplies power to various loads, each connected to or including an optical-electric converter. For example, the optical fiber network can be terminated in various machines and equipment in industrial applications, or in various electronic devices and other devices powered using standard wall outlets in residential or commercial applications. An example of such a network may be the optical power distribution system 800 shown in Figure 13.

[0103] In some embodiments, the optical fiber cable 704 can be coupled to the light source 702 and / or photodetector 706 via optical fiber couplers or connectors 712 and 714 and optical fiber splices 716 and 717 (e.g., mechanical splices, fusion splices, or any other preferred type of splicing device). For example, as shown in Figure 12, the first end 708 of the cable 704 can be coupled to a first splice 716 which can be connected to the first connector 712 via a second optical fiber cable 713 similar to the optical fiber cable 704. The first connector 712 is also coupled to the light source 702 and configured to transfer or transmit optical energy or optical power from the light source 702 to the optical fiber cable 713 and / or 704. Similarly, the second end 710 of the cable 704 can be coupled to a second splice 717 which can be connected to the second connector 714 via a third optical fiber cable 715 similar to the optical fiber cable 704. The second connector 714 is also coupled to the photodetector 706 and is configured to transfer the optical power received via the optical fiber cables 715 and / or 704 to the photodetector 706. As understood, if more optical fiber cables are joined to each other to supply power via the optical fiber power supply system 700, further splices 716 may also be included.

[0104] As shown in Figure 12, the light source 702 is contained within a transmitting unit 718 (also referred herein as an electrical-to-optical ("EO") conversion unit) and configured to convert electrical energy into optical energy (e.g., high-power laser energy) for transmission over an optical fiber cable 704 (similar to the light source 102 in Figure 1). In embodiments, the electrical energy is power received from an external power source (e.g., a DC power source, 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, which uses a power signal received from the power source (or other power input) to drive the operation of the light source 702 (e.g., a laser diode). In some embodiments, the transmitting unit 718 can be coupled to an external control device (e.g., a power control unit 836 shown in Figure 13) which acts as an intermediary between the transmitting unit 718 and the external power source. In such cases, an external control device can manage the amount of power supplied to the transmitting unit 718 and control other operating aspects of the unit 718, for example, according to method 900 in Figure 14.

[0105] As shown in Figure 12, the photodetector 706 (also referred to herein as the photo-to-electric ("OE") conversion unit) is included in the receiving unit 722 and is configured to convert the light energy (or power) received via the optical fiber cable 704 into electrical energy (or power). In embodiments, this electrical energy is used to power one or more electrical loads coupled to the receiving unit 722 (for example, as shown in Figure 13).

[0106] In this embodiment, the receiving unit 722 is also configured to transmit control signals, status signals, feedback signals, and / or other data signals to the transmitting unit 718 via the same optical fiber cable 704 coupled to the transmitting unit 718. Information contained in such data signals can be received from one or more electrical loads coupled to the receiving unit 722 (as described, for example, with respect to Figure 13), or from a control unit (not shown) coupled to a plurality of electrical loads. In this embodiment, the optical fiber 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 contained in the cable 704.

[0107] As shown in the figure, the receiving unit 722 may further include a first processor 724 (e.g., a microprocessor, microcontroller, or similar) 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 optical fiber cable 704. The optical transmitter 726 may be configured to convert the digital data signals into optical data signals or other signals that can be transmitted over the optical fiber cable 704. The optical transmitter 726 may be further configured to supply the optical data signals to the optical fiber 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 optical data signals over the optical fiber cable 704. In some embodiments, the optical transmitter 726 is a laser diode included in the photodiode package of the photodetector 706.

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

[0109] Next, Figure 13 shows an exemplary optical power distribution system 800 according to an embodiment, in which optical fiber cables described herein (for example, as shown in Figure 4) are used as transmission lines for transmitting optical power in the form of high-power laser energy to multiple locations or loads. The optical power distribution system 800 can be used to distribute power over long distances (e.g., intercontinental, international, intercity, etc.) and / or in highly unstable areas where power distribution may be risky, in any industrial, commercial, residential or personal environment, including, for example, in an aircraft, automobile or residence.

[0110] In this embodiment, the optical power distribution system 800 may include n optical fiber feeding systems 801, each substantially similar to the optical fiber feeding system 700 shown in Figure 12. For example, as shown in Figure 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 is substantially similar to the transmitting unit 718 in Figure 12, each OE unit 822 is substantially similar to the receiving unit 722 in Figure 12, and each optical fiber cable 804 is substantially similar to the optical fiber cable 704 in Figure 12. Furthermore, each EO unit 818 can be coupled to each OE unit 822 via the corresponding optical fiber cable 804 and configured to transmit optical power ("OPP") to each OE unit 822 via this cable 804, similar to the case of the optical fiber feeding system 700. For the sake of brevity, the EO unit 818, OE unit 822, and optical fiber cable 804 will not be described in detail here, considering their similarity to Figure 12.

[0111] As shown in Figure 13, each optical fiber power supply system 801 can be coupled to each of the multiple electrical loads 832 and to a common power supply 834. Also, each of the multiple EO units 818 can be coupled to a power control unit 836 (or power controller) electrically connected to the power supply 834. The power supply 834 can be any type of power supply (e.g., DC or AC) or any other device capable of generating enough power to support the electrical loads 832. The power control unit 836 (also called the “master power control unit”) manages the distribution or transmission of the power generated by the power supply 834 to the EO units 818 and can control various other embodiments of the power distribution system 800 as described herein. While Figure 13 shows a single power supply 834 generating power and a single power control unit 836 coupled to it, in other embodiments, the system 800 may also include multiple power supplies and / or multiple control units coupled to multiple EO units 818.

[0112] According to the embodiment, the power control unit 836 can be configured to control the operation of the power supply 834 (e.g., on or off, increase or decrease in the amount of power generated), and / or the operation of each EO unit 818 (e.g., on or off), 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 power distribution by distributing the generated power equally among all 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 load 832 coupled to each EO unit 818.

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

[0114] The electrical load 832 can be any type of device or system that requires 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 its respective OE unit 822 using a wired connection (e.g., an electrical cable or similar) or a wireless connection (e.g., a wireless power transmission system). In embodiments, 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 may include status information, connection information, power requirements information, and / or any other information relating to the management of the power supply. Status information may include, for example, the power factor (or ratio of active power to apparent power) of the electrical load 832, the power utilization rate or other measurement indicating the energy efficiency of the load 832, and any other information relating to the operation or state of the load 832. Connection information may include, for example, connection validator or other indications that load 832 is connected to and / or receiving power from OE unit 822, as well as other information regarding the electrical connection between load 832 and OE unit 822. Power requirements information may include, for example, the power rating of electrical load 832, or the amount of energy required to operate or otherwise support load 832, and other information regarding the power-related needs of load 832.

[0115] Referring further to Figure 12, the OE unit 822 can be configured to receive data provided by the electrical load 832 and process the received data using individual processors (e.g., processor 724 in Figure 12) or other computer devices included in the unit 822. The OE processor can be further configured to generate a data signal (or digital data signal) based on the received data and supply the data signal to an optical transmitter (e.g., optical transmitter 726 in Figure 12) that transmits the data to the EO unit 818. As described with respect to Figure 12, the optical transmitter can convert the digital data signal into an optical data signal suitable for transmission over the optical fiber cable 804 as shown in Figure 13 (also referred to herein as an optical status signal ("OSS")).

[0116] In this 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 that 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 ("OPP"), the power control unit 836 may determine whether it can supply more optical power to the corresponding OE unit 822 by increasing the number of optical fibers in the optical fiber cable 804 used to transmit the optical power to that OE unit 822. In addition to or instead of this, the power control unit 836 may also determine whether the power supply 834 can supply more generated power to the corresponding EO unit 818 in order to increase the total amount of power available to the load 832. In other cases, the power control unit 836 may 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 supplied to the load 832. In any case, if additional power is available, the power control unit 836 may control the EO unit 818 and / or the power supply 834 to ensure that additional power is supplied to each electrical load 832 as needed.

[0117] For example, if all the optical fibers in the optical fiber cable 804 are already in use and the power supply 834 is already operating at maximum capacity and no further power is available, the power control unit 836 can determine that the power supply 834 cannot meet the power requirements of a given electrical load 832, and as a result can terminate the optical link between the corresponding EO unit 818 and the OE unit 822. For example, the power control unit 836 can turn off the light source included in the corresponding EO unit 818, or stop the transmission of optical power through the optical fiber 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 even 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 used, reduce the amount of generated power supplied by the power supply 834 to the laser light source of the EO unit 818, reduce the amount of optical power output by the EO unit 818, and / or control one or more other characteristics of the EO unit 818 and / or the optical fiber cable 804.

[0119] Therefore, while the system 800 avoids grid inefficiencies by adapting to the power requirements of each load 832, it can also be configured to prevent charge buildup and ensure efficient use of the OE / EO infrastructure by using power limiting techniques, such as those further described herein with respect to method 900 in Figure 14.

[0120] The power control unit 836 may include one or more suitable hardware devices that perform the operations described herein, such as a processing device (or processor) and a memory device. The processor may be any suitable hardware device that executes software instructions retrieved from the memory device, such as 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 volatile memory elements (e.g., random access memory (RAM such as DRAM, SRAM, SDRAM, etc.)), non-volatile memory elements (e.g., ROM, hard drives, tapes, and CD-ROMs, etc.), or any combination thereof. Furthermore, the memory device may incorporate electronic storage media, magnetic storage media, optical storage media, and / or other types of storage media. In some embodiments, the memory includes a non-temporary computer-readable medium that implements all or part of one or more of the methods described herein and shown in Figure 14. The memory can store one or more executable computer programs or software modules containing instruction sets to be executed, such as 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 by software, firmware, hardware, or a combination thereof.

[0122] Figure 14 shows an exemplary power supply management process or method 900 in an optical fiber power supply system according to an embodiment, which includes a transmitting unit having a laser light source, a receiving unit having a photodetector, and an optical fiber cable coupled between these units. In some embodiments, the optical fiber power supply system may be substantially similar to any of the optical fiber power supply systems described herein, such as the optical fiber power supply system 700 shown in Figure 12. In some embodiments, the optical fiber power supply system may be an optical power distribution system, such as the optical power distribution system 800 shown in Figure 13, or may be part of a larger optical power distribution system (similar to the optical fiber power supply system 801 in Figure 13, for example).

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

[0124] As shown in Figure 14, Method 902 can begin with step 902, which includes transmitting high-power laser energy from a transmitting unit to a receiving unit using a first number of n optical fibers contained in an optical fiber cable. In embodiments, the optical fiber cable includes a plurality of optical fibers, each extending to the length of the optical fiber cable and surrounded by a thermal filler. For example, the optical fiber cable may be substantially similar to the optical fiber cable 200 shown in Figure 4 and may consist of optical fiber 202 or any other optical fiber cable capable of transmitting laser energy having about 1 gigawatt of power over a distance of about 1,000 kilometers (km) with a loss of about 0.1 decibels (dB). In such embodiments, the transmitting unit can transmit optical power to the receiving unit using all, some, or any other number of optical fibers in the optical fiber 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). In other embodiments, a user or operator of the system can select the first number of optical fibers.

[0125] Step 904 of Method 900 includes receiving in a processor a data signal containing information about the power requirements of an electrical load coupled to the receiving unit, transmitted from the receiving unit to the transmitting unit using the same optical fiber cable used for transmitting high-power laser energy. The power requirements information may include, for example, the power rating of the electrical load, or other information indicating the amount of energy 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 power supply to the electrical load, status information indicating the power factor or power utilization rate of the electrical load, or other information indicating the amount of energy 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] In one embodiment, the data signal is an optical data signal generated by an optical transmitter (e.g., optical transmitter 726 in Figure 12) included in the receiving unit and transmitted over an optical fiber cable. In such an embodiment, step 904 further includes receiving the optical data signal in an optical receiver (e.g., optical receiver 728 in Figure 12) included in the transmitting unit. In step 906, the optical data signal is converted into a digital data signal using, for example, an optical receiver (e.g., a monitor diode) and supplied to the processor.

[0127] In some embodiments, Method 900 further includes using a processor to analyze a data signal and, based on this analysis, controlling the high-power laser energy output by the transmitting unit. For example, if the data signal includes power requirement information for an electrical load, 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, Method 900 includes adjusting or controlling one or more characteristics of the transmitting unit and / or the optical fiber cable to control the high-power laser energy output.

[0128] Specifically, the analysis of the data signal may include, in step 908, identifying power requirement information contained in the data signal and determining whether the power requirement contained in the data signal exceeds a threshold energy amount. In some embodiments, the threshold energy amount may be related to an external power supply coupled to the transmitting unit (e.g., power supply 834 in Figure 13), such as the maximum amount of energy that the external power supply can generate, or other thresholds for the external power supply. In other embodiments, the threshold energy amount may be related to a light source of the transmitting unit (e.g., a laser light source), such as the maximum amount of optical power that the laser can output, or other thresholds for the light source. In yet another embodiment, the threshold energy amount may be related to an optical fiber cable, such as the maximum amount of energy that the cable can carry over its entire length, or other thresholds for the optical fiber cable. Other threshold amounts related to an optical fiber power supply system are also conceivable.

[0129] If the determination in step 908 is positive, i.e., the power requirements of the electrical load exceed a threshold energy amount, 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. That is, if the power required for the operation of the electrical load is greater than the available energy amount, the optical fiber feeding system interrupts the operation of the light source or otherwise stops the supply of optical power through the optical fiber cable.

[0130] If the determination in step 908 is negative, i.e., the power requirements do not exceed a threshold, 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 satisfies the power requirements of the electrical load. For example, the processor may compare the amount of optical power detected by the receiving unit with the amount of power required for the operation of the electrical load to determine whether there is a gap or deficit on the receiving side. If the determination in step 912 is positive, i.e., the power requirements of the electrical load are met, method 900 can terminate.

[0131] On the other hand, if the determination in step 912 is negative, i.e., the received laser energy does not meet the power requirements, method 900 may include controlling or adjusting the high-power laser energy output by the transmitting unit so that the power requirements are met, or adjusting the laser output in a different way to meet the needs of the corresponding electrical load. The exact method for adjusting the laser energy output of the transmitting unit will vary depending on various factors, including, for example, the power requirements of the electrical load, the total number of optical fibers in the optical fiber cable, the power characteristics of the laser light source, and the maximum power capacity of each fiber.

[0132] In some embodiments, step 914 can achieve the above adjustment by adjusting the number of optical fibers used to transmit laser energy from the transmitting unit based on the power requirements of the electrical load, in order to control the form of optical power (OPP) transmitted over the optical fiber cable. For example, in some cases, the transmitting unit can increase the first number of optical fibers initially used to transmit laser energy to a second number of optical fibers greater than the first number. In other cases, the transmitting unit can reduce the number of optical fibers used to a third number less than the first number in order to reduce the amount of optical power transmitted to the receiving side. Thus, step 914 may 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 light source included in the transmitting unit) to use the determined number of optical fibers for optical power transmission to the receiving unit.

[0133] In some cases, the adjustment of the laser energy output in step 916 can be achieved not only by adjusting the number of optical fibers but also by adjusting the amount of power transmitted through each optical fiber. For 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 required, one or more of these fibers can be operated at an even higher capacity (e.g., 80%), or additional fibers can be used, limited to the capacity required to meet the power requirements. Similarly, if less power is required, the total power output can be reduced by controlling or decreasing 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 achieved by adjusting the amount of power output by the laser light source according to the power requirements of the electrical load. For example, to increase the amount of optical power transmitted to the receiving unit, the power setting of the laser light 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. In another example, in an embodiment where the laser light source is a diode array composed of multiple laser diodes, the laser energy output of the laser light source can be adjusted by controlling the number of laser diodes 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, the power requirements of the electrical load can be met using a combination of steps 914 and 916. For example, if the power requirements of the electrical load cannot be met even when all the optical fibers in the optical fiber cable are used, the amount of optical power output by the laser light source can 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 light 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 in the optical fiber cable.

[0136] In some embodiments, the laser energy output by the transmitting unit can be adjusted temporarily or for a set period only to meet, for example, peak load requirements (e.g., during the day) or other temporary needs of the fiber optic power supply 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 then decreasing the number of optical fibers back to the first number at a second time point or after the set period has elapsed. Similarly, step 916 may further include increasing the amount of optical power output by the laser light source from a first setting to a second setting at a first time point, and then decreasing the amount of optical power output by the laser light source back to the first setting at a second time point or after a set period has elapsed. As understood, other techniques can also be used to temporarily adjust the form of optical power transmitted over the fiber optic cable.

[0137] Figure 15 shows an exemplary fiber optic power supply system 1000 configured for use in medical applications according to an embodiment. In some embodiments, the fiber optic power supply system 1000 can be used to remove or excise tumors or other undesirable objects in the human body without major surgery. For example, the fiber optic power supply system 100 can be used for laser-induced hyperthermia, percutaneous laser ablation of certain tumors (e.g., primary and secondary malignant lung tumors and similar), and other appropriate medical procedures (e.g., removal of ureteral stones). Like other fiber optic power supply systems described herein, the fiber optic power supply system 1000 can adjust its laser energy output according to these needs, even if the needs of the receiving end, or in this case, the specific medical procedure being performed, change throughout the procedure. For example, when the system 1000 is used to excise or remove an undesirable object in a patient's body, it 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 hyperthermia and other methods.

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

[0139] Generally, the laser energy emitted through the optical fiber 1004 can be adjusted or optimized to achieve ablation of a specific object 1008. For example, the high-power laser energy output by the laser light source 1002 can be configured to have a wavelength of about 2-3 micrometers (μm) or other appropriate wavelength depending on the object 1042 to be excised. For example, this wavelength can be set to 2.1 μm for tumor ablation and 2.0 μm for ureteral stone ablation. In some embodiments, the laser light source 1002 can be configured to emit pulses of laser energy at a specific rate depending on the type of medical procedure and / or object 1008. For example, the laser light source 1002 can be configured to transmit pulses of laser energy at a repetition rate of 50 Hz when crushing ureteral stones. Alternatively, the laser light source 1002 can be configured to transmit pulses of light energy with a specific amount of power (e.g., pulse output of about 1 joule (J) per pulse) depending on the specific medical application.

[0140] In some embodiments, the laser energy output is adjusted during the ablation procedure to adjust the high-power laser energy according to the specific type of object 1008 as well as the physical structure of object 1008, which changes as ablation is performed. For example, the intensity of the laser energy directed at object 1008 can be reduced as the size of object 1008 decreases and / or as object 1008 breaks into multiple smaller pieces. In some embodiments, such adjustments can be achieved by controlling one or more features or characteristics of the laser energy output, such as the output level of the laser energy output from the laser light source 1002. In some cases, such adjustments can be made initially before the start of the procedure, for example, based on information about the initial size and / or initial shape of object 1008, and continued during the procedure based on status information or feedback information about object 1008 or the rest thereof.

[0141] For this purpose, the optical fiber power supply system 1000 further includes a spectrometer 1010 coupled to a second optical fiber 1012 having a distal end positioned at or near the same location as the first optical fiber 1004 inside the patient 1006 (i.e., adjacent to object 1008). The second optical fiber 1012 may be configured to return the light energy detected at the location of object 1008 to the spectrometer 1010. In embodiments, the second optical fiber 1012 may be substantially similar to one of the optical fibers 202 shown in Figure 4. The spectrometer 1010 may be a near-infrared (or "NTR") spectrometer or other optical spectroscopic device capable of analyzing or measuring various characteristics of the returned light (or light pulse) and determining the state of object 1008 or other incident object based on this analysis. For example, after the initial application of laser energy, the spectrometer 1010 can measure the intensity of the reflected light and analyze the spectral signature of the reflected pulse to determine whether the laser energy output completely removed object 1008, removed only a portion of object 1008, and / or broke object 1008 into multiple small pieces. The spectrometer 1010 can also analyze the signature of the reflected pulse to determine the size of the remaining fragments of object 1008. In some cases, the spectrometer 1010 is configured to analyze the reflected light by identifying the signature of each reflected pulse and comparing these signatures with previously obtained signatures of object 1008 or other prior information to determine how much of the original object 1008 remains, if any. The spectrometer 1010 can also monitor the signature of the reflected pulse, including tissue morphology and absorption characteristics, to evaluate the effectiveness or completeness of the ablation procedure. As can be understood, the spectrometer 1010 can identify and analyze the different colored light contained in the return pulse and the spectral structure of the return pulse in order to make these determinations.

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

[0143] As shown in Figure 15, in some embodiments, the control unit 1014 is a standalone computer device that communicates with both the spectrometer 1012 and the laser light source 1002 via a wired or wireless connection. In other embodiments, the control unit 1014 may be a microcontroller or similar included in the spectrometer 1012, in which case the spectrometer 1012 can communicate with the laser light source 1002. As can be understood, nevertheless, the control unit 1014 may include a processor and memory that perform the operations described herein (for example, similar to those of the receiving unit 722 shown in Figure 12).

[0144] Furthermore, Figure 16 shows a cross-sectional view of an optical fiber 1004 included in the optical fiber power supply system 1000 of Figure 15. In embodiments, the optical fiber 1004 can be configured to allow control of the pulse shape and / or other characteristics of the laser energy supplied through the optical fiber 1004. As shown, the optical fiber 1004 includes a ZBLAN core 1016, which can be substantially similar to the fiber core 212 shown in Figure 4 and described herein. The optical fiber 1004 further includes a cladding 1018 arranged around the ZBLAN core 1016. The cladding 1018 can be fused or bonded to the core 1016, similar to the cladding 214 in Figure 4. The optical fiber cable 1004 further includes a protective coating 1020 configured to protect and isolate the ZBLAN fiber core 1016 and the cladding 1018. The coating 1020 can be made of polyvinyl fluoride ("PVF") or other suitable polymer.

[0145] In the embodiment, the cladding 1018 and coating 1020 can be configured to enable specific control or adjustment of one or more characteristics of the laser energy propagating through the core 1016 of the optical fiber 1004. For example, the cladding 1018 may have a periodic structure configured to guide or direct the propagation of laser energy toward object 1008. The coating 1020 may be an electroactive polymer that can change size or shape when stimulated by an electric field, such as an electric field applied to the cladding 1018 by the control unit 1014 in Figure 15. As the coating 1020 expands and / or contracts in response to the electric field, the period of the periodic structure of the cladding 1018 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 this embodiment, the control unit 1014 can be configured to apply a specific electric field to the cladding 1018 so that the pulse shape and intensity level of the laser energy incident on the object 1008 are adjusted as needed or according to the current state of the object 1008 (e.g., the number and size of remaining fragments).

[0146] In some embodiments, the type of light source 1002 included in the optical fiber power supply system 1000 can be changed or modified according to a specific medical procedure. For example, for the fragmentation of ureteral stones, a standard Ho:YAG laser can be used in such surgical procedures.

[0147] In some embodiments, process descriptions or blocks in figures such as Figures 6, 8, and 14 may represent modules, segments, or portions of code containing one or more executable instructions for implementing a particular logical function or logical step in the process. As those skilled in the art will understand, the scope of the embodiments described herein includes any other implementations in which functions may be executed in an order different from those shown or described, including executing functions substantially simultaneously or in reverse order depending on the functions involved.

[0148] It should be emphasized that the embodiments described above, in particular any “preferred” embodiment, are merely possible examples that illustrate the principles of the present invention clearly. Many changes and modifications can be made to the embodiments described above (one or more) without substantially departing from the spirit and principles of the art described herein. In this specification, all such modifications are intended to be included within the scope of this disclosure and protected by the following claims.

Claims

1. It is a fiber optic cable, The length extending between the first end and the second end, The central cooling tube and A plurality of optical fibers arranged radially around the central cooling tube, each comprising a fiber core and a cladding disposed around the fiber core, wherein the fiber core within each optical fiber comprises ZrF₄-BaF₂-LaF₃-AlF₃-NaF(ZBLAN) material, and each fiber core is configured to have a diameter selected from the range of about 300 micrometers (μm) to about 500 μm, Outer protective cover and An inner thermal filler is disposed between the outer protective cover and the central cooling tube, 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 to the length of the optical fiber cable, and the plurality of optical fibers include at least eight optical fibers, so that the optical fiber cable is configured to transmit laser energy having a wavelength of about 2.1 microns (μm) and a power of about 1 gigawatt over a distance of about 1,000 kilometers (km) with a loss of about 0.1 decibels (dB). Fiber optic cable.

2. The aforementioned inner heat filler is made of acrylic. The optical fiber cable according to claim 1.

3. The central cooling tube includes a cooling material configured to maintain the temperature of the optical fiber cable below a threshold temperature. The optical fiber cable according to claim 1.

4. The cooling substance is air. The optical fiber cable according to claim 3.

5. The aforementioned length is configured to be at least about 50 km. The optical fiber cable according to claim 1.

6. The aforementioned multiple optical fibers include approximately 8,000 optical fibers. The optical fiber cable according to claim 1.

7. The cladding is configured to confine light within the fiber core. The optical fiber cable according to claim 1.

8. The cladding is formed of a fluoride glass material configured to have a lower refractive index than the fiber core. The optical fiber cable according to claim 7.

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