Optical path length adjustment for multichannel optical systems.

Abstract

A system, method, and subsystem for adjusting the optical path length (OPL) of light beams of a multi-channel optical system using an OPL adjustment subsystem comprising an array of OPL adjusters, each configured and arranged to controllably adjust the OPL of the light beam in a corresponding optical channel. For each light beam in each optical channel, one or more current characteristics associated with the light beam are detected, and based on an analysis of the detected data, one or more necessary current adjuster control properties are determined to achieve the associated desired OPL adjustment of the corresponding light beam. Each OPL adjuster is controlled to adjust the OPL of its corresponding light beam in accordance with the determined one or more current adjuster control properties. The detection, analysis, and / or OPL adjustment can be performed in parallel for all optical channels of the multi-channel optical system.

Description

[Technical Field]

[0001] The present disclosure relates generally to optical path length (OPL) adjustment, and more particularly to OPL adjustment of each light beam propagating through a channel of a multi-channel optical system. [Background technology]

[0002] Coherent beam combining (CBC) typically involves combining multiple high-power light beams of similar spectral characteristics into a single light beam formed in the near field (NF) transverse plane as an array of parallel-propagating output light beams to form a focused light spot in the far field (FF) transverse plane. The performance of CBC is measured inter alia by the energy loss of the system and / or the FF beam quality, which is typically related to the spatial distribution / concentration of the energy / power of the combined light beam obtained from the CBC system in the FF transverse plane.

[0003] The FF beam quality can be expressed as the power in bucket (PIB) performance of the combined beam, which indicates the spatial concentration of the power / energy of the combined beam in the FF transverse plane. In a CBC system, the FF performance (beam quality) of the combined beam output from the CBC system / mechanism is usually sensitive to the difference between the phase, degree of polarization, and optical path length (OPL) of the input light beams being combined by the CBC system and the phase, degree of polarization, and OPL of the output light beam output from the CBC system.

[0004] For example, a high PIB is associated with low energy loss and / or high energy concentration within a single light spot with a small spatial distribution (less spot spread) of the combined beam at the FF, and is best when all input beams being combined by the CBC system have correlated or identical polarization, phase, and OPL, thereby allowing all beams output from the CBC system to constructively interfere with each other at the FF. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 174461 [Patent Document 2] International Publication No. 2022 / 003669 [Patent Document 3] IL284740 [Patent Document 4] IL294523 [Patent Document 5] US Patent Application Publication No. 2023 / 0134874 [Patent Document 6] International Publication No. 2023 / 281513 Summary of the Invention [Means for solving the problem]

[0006] An aspect of the disclosed embodiment is a detection and control subsystem for a multi-channel optical system comprising at least one fiber array of optical fibers, thereby guiding a plurality of optical beams through its respective waveguiding units defining an array of optical channels, the detection and control subsystem comprising: (i) an optical path length (OPL) adjustment subsystem comprising an array of OPL adjusters each constructed and arranged to controllably adjust an optical beam OPL of each optical channel of the multi-channel optical system; (ii) for each optical beam of each optical channel of the multi-channel system, at least receiving one or more current detected characteristics associated with the light beam; analyzing the received one or more characteristics to determine one or more updated adjuster control properties required to achieve the desired associated OPL adjustment of the light beam; Controlling the OPL adjusters of the optical channels to adjust the OPL of the light beam according to the determined one or more latest adjuster control properties, wherein the detection, analysis, and OPL adjustment are performed in parallel for all optical channels of the multi-channel optical system. at least one control unit configured to The present invention relates to a detection and control subsystem comprising at least:

[0007] Another aspect of the disclosed embodiments is a method for adjusting an optical path length (OPL) of a multi-channel optical system using a fiber array of a plurality of optical fibers for respectively guiding a plurality of optical beams passing therethrough to define a corresponding array of optical channels, the method comprising: providing an OPL adjustment subsystem comprising at least one array of OPL adjusters each configured to at least adjust an OPL of each light beam of the multi-channel optical system; providing a control unit configured to process the received data and control at least each OPL regulator; For each optical channel, detecting, using a detection unit, one or more current optical characteristics associated with the light beam of each optical channel output from the multi-channel optical system; analyzing the received one or more characteristics of the optical beam of each optical channel to determine, with a control unit, one or more current adjuster control properties each associated with a required current OPL adjustment for the optical beam propagating through each optical channel; and adjusting, with the control unit, the OPL of each light beam by controlling each OPL adjuster according to the determined one or more latest adjuster control properties, wherein the detection, analysis, and OPL adjustment are performed in parallel for all optical channels of the multi-channel optical system. Regarding the method.

[0008] An additional or alternative aspect of the disclosed embodiments relates to an OPL adjuster for adjusting the OPL of a light beam passing through an optical fiber, wherein the OPL adjustment is based on temperature control of one or more fiber sections of the optical fiber or additional fiber sections coupled to the fiber sections.

[0009] An additional or alternative aspect of the disclosed embodiments relates to an OPL adjuster for adjusting the OPL of a light beam passing through an optical fiber, wherein the OPL adjustment is based on routing the light beam through one or more selectable optical paths.

[0010] The figures illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0011] For simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale, and reference numerals may be repeated among the figures to indicate corresponding or similar elements. The figures are listed below. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 10 illustrates how the coherence length ΔLc of light sources used for a coherent beam combining (CBC) system can be determined, and the desired and / or minimum optical path difference (OPD) corresponding to the coherence length between light beams combined by the CBC unit of the CBC system, according to some embodiments. [Figure 2]FIG. 1 illustrates a CBC system using a detection and control subsystem with an OPL adjustment subsystem built into it, according to some embodiments. [Figure 3A] FIG. 1 is a diagram of a single channel system using a single working optical fiber with a temperature control element coupled to one or more sections, and a reference optical fiber for OPL adjustment by adjusting the length of the working optical fiber, in accordance with some embodiments, based on measurements related to interference between a light beam output from the length-controlled working optical fiber and a reference beam output from the reference optical fiber. [Figure 3B] 1 is a schematic illustration of the difference in the sequence of interference intensities. [Figure 4] FIG. 1 is a diagram of one implementation of a controllable temperature regulator comprising a heat conducting element, in accordance with some embodiments, in which temperature control of a portion of an optical fiber is achieved by wrapping the portion of the optical fiber around the heat conducting element. [Figure 5] FIG. 10 is a diagram of another implementation of a controllable temperature regulator comprising a thermally conductive wire or strap wrapped around a portion of an optical fiber, according to some embodiments. [Figure 6] 1 is a flow diagram that schematically illustrates a procedure / method for a CBC system that adjusts fiber length based on per-channel temperature control for OPL adjustment of multiple input light beams, according to some embodiments. [Figure 7] 1 is a flow chart illustrating a procedure / method for a CBC system that adjusts fiber length based on per-channel temperature control for OPL adjustment of multiple input light beams, according to some embodiments, the procedure / method including using a reference light beam to measure the optical path difference (OPD) of the CBC channels. [Figure 8]FIG. 1B is a schematic diagram of a multi-channel optical system for OPL modulation by irradiating additional fiber sections using a detection and control subsystem that uses an OPL modulation subsystem based on temperature control by adding additional fiber sections spliced / coupled to the optical fiber of each channel, according to some embodiments. [Figure 9] 1 is a flow diagram that schematically illustrates a method for temperature control based on OPL adjustment of the OPL of multiple light beams in a CBC system, according to some embodiments. [Figure 10] FIG. 1 is a schematic diagram of an OPL adjuster or portion thereof based on selectable opto-mechanical routing of an incident light beam using a manifold of light guides (fibers), according to some embodiments. [Figure 11] 1 is a schematic diagram of an OPL adjuster or portion thereof based on selectable opto-mechanical routing of an incident light beam using multiple reflectors, according to some embodiments. [Figure 12] 1 is a flow diagram that schematically illustrates a method for OPL adjustment of light beams of a CBC system based on a selected path determination of each light beam, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0013] Aspects of the disclosed embodiments relate to systems, subsystems, units, and methods for adjusting the optical path length (OPL) of one or more light beams. The OPL adjustment may be performed for any of a number of purposes, such as, for example, to reduce the optical path difference (OPD) of a multi-channel optical system, such as a coherent beam combining (CBC) system or a spectral beam combining (SBC) system, or to mitigate undesired OPL changes that occur in such systems and / or other system devices due to, for example, heat generated by the light beams undesirably changing the refractive index of, for example, each optical fiber in the multi-channel optical system through which the light beams propagate. This undesired change in refractive index may be inconsistent and different between different optical channels of the system, thereby adversely affecting the performance of the multi-channel system.

[0014] The terms "channel" and "optical channel" may be used interchangeably herein.

[0015] The terms "light beam" and "beam" may be used interchangeably herein.

[0016] The terms "optical fiber" and "fiber" may be used interchangeably herein.

[0017] Multi-channel optical systems, such as CBC systems, typically employ tens or even hundreds of high-power fiber amplifiers and therefore inevitably exhibit dynamic variations in fiber OPL, which in turn results in dynamic OPD variations between different optical beams during system operation. To maintain efficient / improved CBC performance, this variation in OPD can be dynamically mitigated by the disclosed embodiments.

[0018] The main cause of the change in OPL (which gives rise to OPD) is the temperature change of different optical fibers and / or portions thereof.

[0019] The OPL of an optical fiber can be estimated using the following mathematical relationship between the total OPL of a light beam passing through (guided by) the fiber and the length of the fiber:

number

[0020] The dependence of OPL on temperature change ΔT gives rise to the optical path difference (OPD), which can be roughly expressed as: OPD fiber (ΔT)=α T n fiber ΔT operation +α n L fiber ΔT operation (In the formula,

number

number

[0021] Fused silica has a low CTE, which means that the material expands / contracts only slightly with temperature. The CTE of fused silica is α over the temperature range of 0°C to 200°C (degrees Celsius). T =0.55x10 -6 / ℃.

[0022] Fused Silica

number

[0023] For example, a temperature change of ΔT=1°C between two fibers results in a change in refractive index from 1.4496 to 1.449611, which translates to an optical path difference of 0.33 mm for a 30 m (meter) long fiber. This change is already larger than the required optical path difference between the channels, which can have adverse effects on the beam combining performance, such as increased energy / power loss, and can adversely affect (cause an increase in) the spatial energy distribution of the combined beam in the far-field (FF) transverse plane.

[0024] In order to control the OPL of each light beam in a multi-channel optical system, the effect of the change in refractive index due to the change in temperature of the fiber can be used by varying (controlling) the temperature of the fiber or one or more portions thereof to at least actively heat one or more portions of one or more optical fibers of the system, using one or more heating elements / devices or by using optical radiation (light) to heat the fiber section by heat absorption, thereby controlling the overall length of each optical fiber.

[0025] According to other embodiments, one or more opto-mechanical elements may be used to control the OPL of each light beam, for example by controllably routing the light beam through one of a variety of routes (optical paths and / or light guide paths) of different lengths available through the OPL adjustment means.

[0026] Embodiments of the invention disclosed herein may be directed to enabling adjustment of the optical path length (OPL) of a light beam passing through an optical fiber by adjusting the length of each optical fiber. Adjustment of the fiber length may be achieved by heating and / or cooling (temperature regulation / control) one or more sections of the optical fiber using one or more temperature control means coupled to one or more fiber sections, such as one or more electrically controllable heat conducting elements, one or more thermoelectric coolers (TECs), etc.

[0027] CBC systems require low OPD between input beams to ensure high FF performance of the combined beam generated by combining the input beams. To easily and stably align the input optical beams to be combined with other optical elements and / or mechanisms in the CBC system, multiple optical fibers are often used to guide the multiple optical beams in a CBC system. To reduce / minimize the OPD between different input optical beams when using multiple optical fibers, all fibers in a CBC system must initially have the same overall length or precisely differ from each other by a specific and precise ratio to adjust the OPL of the beams passing therethrough. Inaccurate or misaligned OPL of the input optical beams can result in undesirable OPD between channels in the CBC system, thereby adversely affecting the beam combining performance.

[0028] Inaccuracies or inconsistencies in OPL often arise due to limitations in fiber manufacturing and / or cutting accuracy, and / or due to uncontrolled heating or cooling of the fiber during system operation due to heat generated by the beams passing through the fiber, especially when using high-power amplifying fibers, and / or due to inaccuracies and / or variations in the length of the optical fiber caused by external / environmental factors that cause uneven heating / cooling of the fiber. Uncontrolled heating / cooling of the fiber can cause uncontrolled changes in fiber length, which can easily degrade / impair the performance of the CBC, especially in the case of CBC systems, due to varying lengths of the fibers in use and therefore varying OPD between beams.

[0029] A further object of embodiments of the present invention may relate to improving at least FF combined beam performance, such as improving power-in-bucket (PIB) performance of the FF combined beam, by using channel-specific OPL adjustment of the optical fiber in use to enable ongoing OPL adjustment for each optical fiber in a fiber array used in a CBC system.

[0030] The optical path difference (OPD) between the input light beams to be combined by a CBC system determines the contrast with which these beams can interfere. A small contrast means a poor coupling efficiency and therefore a poor PIB. To achieve a suitable modulation depth or contrast value that allows a potential coupling efficiency of 99%, the OPD must be smaller than the coherence length ΔL of the light sources used to generate the input light beams. C The contrast should be significantly shorter than (MAX amp -MIN amp ):(MAX amp +MIN amp ) (amp refers to the amplitude value).

[0031] For example, a source laser with a wavelength of 1 μm (micrometer) and a spectral width of 50 GHz has a coherence length of 1.9 mm. This means that if the OPD between channels of a CBC system using, for example, a single (split) source is 1.9 mm, the modulation depth between the input beams will be reduced by 1 / e. In a CBC system using multiple high-power fiber amplifiers, for efficient coupling, the OPD between all channels must be less than the coherence length ΔL, such as less than 200 μm (0.2 mm) in the example above. C It needs to be at least one order of magnitude smaller than

[0032] Figure 1 shows the coherence length ΔL measured by measuring the distance between the maximum and minimum amplitude peaks of the optical signal output from the light source. C is determined, and based on this, the desired achievable OPD length is calculated as the coherence length ΔL C For example, to potentially achieve 99% CBC efficiency in a CBC system using a single (split) light source, the desired OPD can be determined by verifying that the coherence length ΔL of the output optical signal from the light source is 0.99Aspects of the disclosed embodiments relate to a CBC system that uses multiple optical fibers, each guiding multiple input light beams, that defines multiple channels of the CBC, with an OPL adjustment subsystem or mechanism incorporated into the CBC system that performs continuous or periodic OPL adjustment based on parallel per-channel OPL adjustments made by separate controllable OPL adjusters (for each fiber) (at least one OPL adjuster for each fiber / channel of the CBC system).

[0033] The term CBC may refer to any CBC system / method that combines multiple input light beams with the same or similar spectral characteristics, such as the same / similar wavelength (WL) and / or WL bandwidth.

[0034] The input light beams used for CBC may have other identical or similar optical properties, such as identical or similar beam profile characteristics, identical or similar wavefront characteristics, etc.

[0035] Aspects of the disclosed embodiments relate to an optical path length (OPL) adjustment subsystem for a coherent beam combining (CBC) system that uses a waveguiding unit comprising at least one fiber array of a plurality of optical fibers, such as a plurality of amplifying fibers, to guide corresponding input light beams through the fibers, define an array of optical channels by real time (RT) or near RT measurements, and / or determine the required beam OPL adjustments and corresponding fiber-by-fiber (also referred to herein as "channel-by-channel") adjustments based on temperature control of the OPL for each of the optical fibers of the fiber array according to specific, defined beam OPL adjustments of each specific input light beam, each guided by a specific optical fiber.

[0036] According to some embodiments, the CBC system may comprise a CBC unit including any one or more CBC devices and / or elements for a parallel CBC (e.g., using at least one array of collimators and / or beam shapers) or a field aperture CBC using a single diffractive element, such as a diffraction grating element, to combine all input light beams to output an array of coherent light beams with parallel propagation directions (in the near-field cross-plane) such that all output light beams have parallel propagation directions and, optionally, similar other optical properties such as phase, phase and / or energy distribution, polarization, etc.

[0037] According to some embodiments, the OPL adjustment for each channel of the light beams of the CBC system may be based on at least one characteristic / parameter of the light beams of each channel, such as the intensity / power of each light beam output from the CBC unit or the intensity / power of each interference signal between the light beams of each channel and a reference light beam, which can be detected using an array of optical detectors, each of which is positioned and configured to detect the intensity of the light beams or interference signals of a different channel.

[0038] According to some embodiments, OPL adjustment of each optical beam of the CBC system may be performed to improve characteristics related to beam combining performance, such as optimizing / mitigating / minimizing OPD between the optical beams of the CBC system to mitigate / minimize energy loss, mitigating / minimizing power in the bucket (PIB) in the far-field (FF) cross-plane, which is related to the energy / power distribution of the combined beam light spot across the FF cross-plane, etc.

[0039] According to some embodiments, the OPL adjustment subsystem may be configured to continuously and in parallel receive and analyze output data / signals from each of an array of optical detectors configured and positioned to detect intensity-related parameter values ​​for each channel (e.g., the intensity of interference between each light beam output from the CBC unit and a corresponding portion of a reference light beam), and determine the required OPL adjustment for each light beam and a control operation of at least one OPL adjuster in each channel to adjust the OPL of each light beam, thereby enabling OPD control / adjustment between multiple channels of the CBC system, for example, to mitigate OPD between the light beams.

[0040] The OPL adjusters of the OPL adjustment subsystem may be designed to adjust the OPL of each light beam by controlling the overall length of one or more fibers through which each light beam propagates, for example, by adjusting the length of one such fiber of each channel by heating or cooling the fiber (temperature control) or by routing the light beam through a multi-path light guide, such as a manifold of routing optical fibers configured to adjust and control the path length or a controlled / adjustable reflection-based multi-path.

[0041] According to some embodiments, the OPL adjustment subsystem comprises: (i) an OPL adjustment array comprising at least one array of per-fiber controllable OPL adjusters, each coupled to or located adjacent to at least one portion of a corresponding different optical fiber of the fiber array, and configured to adjust the OPL of a corresponding input beam guided by the optical fiber by temperature-controlled adjustment of the entire length of the corresponding optical fiber; (ii) at least: receiving one or more recently measured characteristics associated with a corresponding output light beam of each optical channel emanating from a CBC unit designed and arranged to combine all of the input light beams output from the fiber array; For each optical channel, analyzing the received one or more measured characteristics of the corresponding output light beam to determine a current required OPL of the corresponding input light beam and its corresponding required fiber temperature adjustment; Controlling the corresponding temperature regulator of the corresponding optical fiber to adjust the overall length of the corresponding optical fiber to adjust the OPL of the corresponding input light beam. A control unit configured as follows: may be provided.

[0042] According to some embodiments, measurement of one or more properties and temperature control may be performed simultaneously or nearly simultaneously for all channels of a CBC system in parallel on a channel-by-channel basis in a recursive feedback loop to improve the far-field (FF) beam combining performance of the CBC system.

[0043] According to some embodiments, the OPL adjustment subsystem may be incorporated into a CBC system to use the measurement, processing, and / or control hardware and / or software means of the CBC system that are also used for other CBCs to measure / determine the required OPL adjustment for each channel and / or temperature control for controlling the length of fiber. For example, the same detection means may be used for closed / feedback loop per-channel OPL, phase, and / or polarization adjustment and regulation, allowing for continuous simultaneous or near-simultaneous adjustment (e.g., matching) of the OPL, phase, and polarization of all input light beams of the CBC system, thereby enabling optimal and substantially improved FF-CBC performance.

[0044] According to some embodiments, the OPL conditioning subsystem may also include a sensor array comprising a plurality of temperature sensors, each positioned and configured to directly measure temperature proximate a temperature-controlled section of the optical fiber in which at least one temperature regulator is each positioned.

[0045] According to some embodiments, the OPL adjustment subsystem may also be configured to estimate / calculate a "temperature-adjustment period" (TAP), which is an estimate of the time required to heat / cool a fiber section of a particular optical fiber to achieve a required fiber length corresponding to a required OPL of an input beam passing through the optical fiber. The OPL adjustment subsystem may also be configured to control the heating / cooling of the fiber section based on the estimated TAP.

[0046] It should be noted that TAP may be such that, for example, heating the fiber requires a known "Th" time for each degree Celsius increase (heating) and a known "Tc" time for each degree Celsius decrease (cooling), where Tc and Th may depend on the temperature difference ΔT between the estimated / known current temperature of the fiber section and the estimated new temperature required to obtain the desired fiber length and corresponding beam OPL, which may be equal or different depending on the temperature control device and method being used.

[0047] For example, if the temperature regulators used are heating elements that can only actively heat and only passively cool (through natural heat dissipation), and each temperature regulator is coupled to a fiber section of a different fiber, Tc may be significantly greater than Th.

[0048] In other cases where the temperature regulator being used allows for both active heating and active cooling, Tc may be equal to Th or may be significantly closer in value to Th for the passive cooling case.

[0049] Thus, the OPL regulation subsystem can be adapted to the particular thermostat type being used and its associated heating and cooling tap values ​​in calculating / estimating the heating and cooling taps.

[0050] In some cases, depending on, for example, the characteristics of the light source, the phase of each input light beam may change much more rapidly than the OPL of the input light beam. Furthermore, the rate at which the overall length of the fiber can be adjusted may also be much less than the rate of phase change and / or phase adjustment. One solution may include continuously measuring the OPD along with phase-related measurements adapted to the phase change of the CBC system, and adjusting the fiber length based on the temperature control of the OPL at different rates adapted to the time required to heat or cool the fiber section to achieve the corresponding required fiber length.

[0051] According to some embodiments, the CBC system may include (in addition to OPL adjustment related components and operations) components, devices and / or operations for, e.g., phase and / or polarization adjustment, optical aberration correction, beam shaping, etc., such as any one of the components and / or operations described in the following references, which are incorporated herein by reference: WO 2020 / 174461, WO 2022 / 003669, IL284740, and IL294523.

[0052] Reference is now made to FIG. 2, which illustrates a multi-channel optical system such as a CBC system 1000 that employs a detection and control subsystem 1010 with an OPL adjustment subsystem or mechanism built into it, according to some embodiments.

[0053] The CBC System 1000 is an illumination unit comprising a single light source 1001 and a beam splitter 1002 configured to split the light emitted from the light source 1001 to form an array of input light beams of similar wavelength (WL) and optionally similar optical properties such as similar phase and / or energy spatial distribution (profile); a waveguiding unit comprising at least one fiber array 1100 comprising a plurality of optical fibers 1101, all of the fibers 1101 being coupled / coupled to a beam splitter 1002, such that each input light beam formed by the beam splitter 1002 is guided through a corresponding different optical fiber 1101 of the fiber array 1100; a CBC unit 1400 as taught in any one or more of the following patents or applications: U.S. Patent Application Publication No. 2023 / 0134874; WO 2023 / 281513; IL294523; IL284740; and a CBC unit 1400 configured and arranged to receive an array of input light beams output from the output ends of the fibers 1101 of the fiber array 1100, which may comprise at least one CBC optical element such as a diffraction grating element (for a field aperture CBC) or at least one array of optical elements such as CBC elements 1401 (for a parallel CBC), such as at least one array of collimation lenses, a beam shaping array, an error correction array, etc. a detection and control subsystem 1010, an OPL adjustment subsystem comprising at least one OPL adjuster array 1200 comprising a plurality of per-channel OPL adjusters 1201, each OPL adjuster being capable of being coupled to or positioned adjacent a fiber section of a different optical fiber 1101 of the fiber array 1100, each OPL adjuster 1201 being configured to controllably adjust the overall OPL of a corresponding input light beam passing through and guided by it; and (Optionally) a phase locking unit comprising a phase adjustment array 1300 comprising a plurality of per-channel phase adjusters 1301 configured to controllably adjust the phase of different input light beams. a detection and control subsystem 1010 comprising: A reference unit, a beam splitter (BS) 1003 for simultaneously splitting each of all output light beams OB output from the CBC unit 1400 such that a first portion of each output light beam OB is directed parallel to a first propagation axis x, which may be, for example, parallel to the optical axis of the CBC system, and a second portion of the output light beam is directed in another direction parallel to a second propagation axis y that is at an angle (e.g., perpendicular) to the first propagation direction x; and a reference fiber 1005 connected directly or indirectly to the light source 1001 or directly to the beam splitter 1002 to guide / wave-guid a reference light beam RB having similar / identical optical properties to the light / beam output from the light source 1001, e.g., outputting a reference light beam RB that is spatially distributed and propagating in such a way that it simultaneously interferes with each of the output light beams that are guided by the BS 1003 and propagating parallel to the second propagation direction, such that the propagation direction of the reference beam RB is substantially parallel to the second propagation direction; a reference unit comprising: a detection unit 1500 comprising photodetectors 1501, such as an array of photodetectors, and optionally a lenslet array 1550, each photodetector 1501 being arranged to measure one or more characteristics, such as the intensity of a corresponding interference signal of a different channel, and latest output intensity-related data (which may be in the form of an electrical signal) indicative of the measured intensity of the corresponding interference signal, the detection unit 1500 being configured to detect at least the intensity-related characteristics for each channel of the interference signal resulting from the interference of each output light beam portion directed along the second propagation direction with the reference light beam RB; For each channel "i" in the CBC system 1000, at least (a) receiving the most recent intensity-related output data value Ii of the interference signal of channel "i", each detected by the photodetector 1501 of the detection unit 1500; (b) processing the most recently received intensity-related data value Ii; - a current required OPL adjustment OPLi of the corresponding input light beam of each channel "i" and its corresponding current required fiber length FLi and corresponding current required temperature adjustment Tai (and optionally an estimated temperature adjustment period TAPi value) and / or characteristics for the current required adjuster control, for controlling the OPL adjuster of each channel "i" to achieve the associated desired / required OPL adjustment of the corresponding light beam, and - Controlling the corresponding OPL regulator of channel "i" according to its determined current regulator control characteristics to improve / optimize FF CBC performance. Define at least one of The main control unit 1600 configured as follows: may be provided.

[0054] The above operations of the master controller 1600 may be performed in a recursive / periodic / sustained feedback loop in parallel for all channels of the CBC system 1000.

[0055] According to some embodiments, the OPL adjustment for each channel may be performed to minimize or maximize the intensity / power value of the interference signal for each channel, and adjust / fix the OPL of the corresponding input light beam when the interference signal of its corresponding output light beam with the reference light beam RB produces maximum constructive or destructive interference. For example, the main controller 1600 may be configured to regularly vary the phase of each input light beam to different values ​​over time (increasing or decreasing by a predetermined shift), and detect / determine when the total power / intensity of the interference signal output from the corresponding photodetector 1501 reaches a maximum value (with respect to the channel's previous and most recently measured intensity-related signal values), thereby fixing the phase at that rate.

[0056] According to some embodiments, the detection and control subsystem 1010 may further comprise a phase and / or polarization fixing means for fixing the phase and / or polarization orientation / direction of each of the input light beams in parallel, which may be based on analysis / processing of the latest intensity-related data output from the photodetector 1501 of the detection unit 1500 and may be based on detection / determination of extreme values ​​of the intensity of the interference signal of each optical channel.

[0057] The phase and / or polarization of each input light beam may be controlled / adjusted by its corresponding phase and / or polarization adjuster and controlling OPL adjuster 1201 .

[0058] According to some embodiments, the adjustment of the OPL, phase and / or polarization of each input light beam of each channel can be performed by changing / shifting the phase, polarization and / or OPL by a predetermined shift step and identifying when the change causes the intensity / power of the interference signal to reach an extreme, i.e., a maximum or minimum value among all two or more previously measured interference signal intensities of the same channel "i" over a short measurement period Δt.

[0059] According to some embodiments, the intensities of the interference signals of all channels are measured in parallel by the detection unit 1500, so that the phase and / or polarization and OPL of each input light beam can be detected and controlled in parallel and fixed by the same ultimate intensity detection / characterization using the same control unit, such as the main control unit 1600.

[0060] According to some embodiments, the CBC system 1000 may also include one or more mechanisms for beam steering the combined light beam formed by the output light beams in the FF transverse plane. For example, as shown in FIG. 2 , the CBC system 1000 may further include a modulation array 1700 including multiple phase modulators 1701, such as spatial light modulators (SLMs), each configured to phase-modulate a different section of the reference light beam RB before it interferes with the corresponding output light beam. This allows controlled beam steering of the combined light beam by setting the phase of each phase modulator to a different desired and pre-calculated phase such that its corresponding input light beam automatically locks to its corresponding phase, thereby achieving an extreme intensity / power value of the corresponding interference signal. The phase difference between each input light beam and, therefore, its corresponding output light beam may be adapted to a target position of the FF that is not necessarily aligned with the optical axis x of the CBC system 1000, allowing for controllable steering of the combined light beam in any direction simply by calculating the required phase difference between the light beams. This phase modulation may be controllable by the same control unit, such as main control unit 1600, which may be configured to receive steering information, such as target position, as input data from a user and / or another control system.

[0061] Additionally or alternatively, controllable opto-mechanical means can be used for beam steering, such as a controllably positioned reflector or additional beam splitter that can reflect and direct the output beam, and the angled position and / or location of the reflector / beam splitter can be controllably adjusted by the main controller 1600.

[0062] According to some embodiments, one or more optical elements such as a collimator 1006 (FIG. 2), a Fresnel lens, a phase element, a beam shaper and / or a convex lens may be used to form a reference beam having a wide / large enough light spot with a spatial distribution of energy and / or phase that is as uniform / homogenous as possible, so as to interfere with the reference light beam RB with each of the output beams directed and output by the BS 1003 and propagate in the second propagation direction.

[0063] According to some embodiments, the main controller 1600 may be wired and / or wirelessly connected to communicate with one or more of each OPL adjuster 1201, the light source 1001, the beam splitter 1002, each phase adjuster 1301, each photodetector 1501, and each phase modulator 1701 for communication and / or control purposes.

[0064] According to some embodiments, each OPL adjuster 1201 may include one or more heat-conducting elements each coupled to a specific fiber portion of each optical fiber 1101, and each heat-conducting element may be connected to the main controller 1600 by an electrical wire to actively and controllably heat the heat-conducting element, thereby adjusting the length of the corresponding fiber for OPL adjustment by its expansion, or may passively cool the corresponding fiber portion by natural heat dissipation, thereby adjusting the length of the fiber for OPL adjustment by its contraction.

[0065] According to some embodiments, the master controller 1600 may use a predetermined table or data array or predetermined calculation / algorithm associated with and enabling the calculation of the required increase / decrease in OPL along with the corresponding temperature increase / decrease. For example, for an optical fiber with known physical properties, such as its initial and / or room temperature length, material from which the fiber is made, fiber diameter / dimensions, fiber cladding material and thickness, refractive index characteristics, etc., and for known expected optical properties of the input beam, such as WL and WL bandwidth, intensity / power peak value per beam, etc., a specific calculation function / equation may be established with coefficient values ​​adapted to the known properties of the particular fiber and input beam, such that the required temperature or temperature difference value per channel can be calculated quickly at RT based on the estimated required input beam OPL.

[0066] Additionally or alternatively, a table or data array may also be established based on a pre-calculated relationship between OPL and temperature values ​​to quickly determine the temperature or temperature difference required for the desired input beam OPL.

[0067] For example, for a CBC system using a known specific type of amplifying fiber with known fiber properties, a specific temperature regulator and the area of ​​the fiber section to which it is coupled, and known optical characteristics of the input beam, the master controller may have a pre-defined algorithm that can estimate, for example, each required OPL expansion / contraction, the corresponding required ΔL length expansion / contraction of the fiber, and the corresponding required Celsius temperature increase / decrease and also the corresponding required TAP duration for heating / cooling the specific fiber section to achieve the required OPL expansion / contraction.

[0068] According to some embodiments, the OPL regulation subsystem of the CBC system 1000 may include one or more hardware and / or software modules / units of an OPL regulator array 1200, a detection unit 1500, and a master controller 1600 associated with OPL regulation and temperature control.

[0069] FIG. 3A shows an OPL adjustment subsystem 100 for performing OPL adjustment based on temperature control of a length of fiber using a stand-alone optical fiber 110 and a reference optical fiber 105 with a controllable temperature-controlled OPL adjuster 120 coupled to the fiber section, according to some embodiments.

[0070] The reference optical fiber 105 can be used to correlate the OPL of a first light beam guided by the working optical fiber 110 with the OPL of a second light beam (e.g., having optical properties identical / similar to those of the first light beam) guided by the reference optical fiber 105, both of which emanate from the same light source 101.

[0071] According to some embodiments, the OPL adjustment subsystem 100 also includes: a first optical unit 180A, for example comprising a collimator 181A and a beam splitter or reflector 182A; a second optical unit 180B comprising, for example, a collimator 181B and a reflector or beam splitter 182B; a single photodetector 150 positioned and configured to measure characteristics of an interference signal formed by the interference of the first and second light beams emanating from the working optical fiber 110 and the reference optical fiber 105, respectively (this interference being made possible by the first optical unit 180A and the second optical unit 180B); a controller 160 configured to receive the latest output data / signal from the photodetector 150, process the received data / signal to determine the latest required adjustments related to the OPL and their corresponding fiber length and / or temperature adjustments, and control the controllable OPL adjuster 120 based on the latest output data / signal analysis results; You can prepare.

[0072] According to some embodiments, as shown in FIG. 3A, the OPL adjustment subsystem 100 may further comprise a phase modulator 130 that is installed, connected, and used to modulate the phase of the second light beam passing through the reference optical fiber 105.

[0073] According to some embodiments, the phase modulator 130 may be configured to create / induce a short phase sequence (e.g., a "sawtooth" shape) in the transmitted field of the second optical beam. The interference intensity sequence can be collected by a high-speed photodetector 150. The contrast of this intensity sequence between the intensity amplitudes (as shown in FIG. 3B and described with respect to FIG. 1) can be maximized by a controllable OPL adjuster 120 attached to the optical fiber 110 used. The OPD between the first and second optical beams can be minimized by a closed-loop or feedback-loop mechanism based on the temperature of the fiber section of the optical fiber 110 used, which achieves a maximum contrast value.

[0074] 4 shows one implementation of a controllable OPL regulator 30 comprising a heat-conducting element 31, according to some embodiments, where thermal control of a section of optical fiber is achieved by wrapping a section of optical fiber 10 around the heat-conducting element 31. The heat-conducting element 31 may be connected to a controller by an electrical wire 33 to allow controllable heating of the heat-conducting element 31 by controlling voltage / current transfer to the heat-conducting element 31 (which may also be electrically conductive).

[0075] According to some embodiments, the length "L1" of the fiber portion of the optical fiber 10 in contact with the heat conducting element 31 of the controllable OPL adjuster 30 is related to the number of winding loops formed or the width or diameter D1 of the heat conducting element 31.

[0076] This arrangement of the controllable OPL adjuster 30 may be easier to implement, may require less space for the OPL adjuster 30, and may allow for some thermal insulation between the heat conducting element 31 of a particular optical fiber 10 and other adjacent fibers in a manner that prevents or reduces changes in the length of adjacent fibers due to temperature control of the particular fiber 10, since the optical fiber 10 itself also functions as a covering element that is wrapped around the surface of the heat conducting element 31 to cover it.

[0077] 5 shows another implementation of a controllable OPL adjuster 40, according to some embodiments, that includes a conductive element, such as a thermally conductive wire 41 or strap, wrapped around a portion of optical fiber 20. Thermally conductive wire 41 may be connected to a controller by electrical wire 43 to allow controllable heating of thermally conductive element 41 by controlling voltage / current transfer to thermally conductive element 41 (which may also be electrically conductive).

[0078] According to some embodiments, the length D2 is defined as the length of the fiber portion of the optical fiber 20 for adjusting the fiber length based on temperature control, which also defines the contact area between the optical fiber 20 and the thermally conductive wire 41 of the controllable OPL adjuster 40.

[0079] This arrangement of the controllable OPL adjuster 40 may require coating of the exposed thermally conductive wire 41 with an insulating coating, such as an insulating cladding sleeve (not shown), to reduce / prevent / minimize thermal impact on adjacent fibers, but may allow the optical fiber 20 to more easily and quickly dissipate its natural heat for faster cooling.

[0080] Reference is now made to Figure 6, which is a flow chart illustrating a procedure / method for channel-by-channel OPL adjustment of multiple input light beams in a CBC multi-channel optical system, according to some embodiments. The method comprises at least: directing a plurality of input light beams of a CBC system through a corresponding plurality of optical fibers and a CBC unit to produce a plurality of output beams in a near-field (NF) region of the CBC system (step 51); For each optical channel "i" in a CBC multi-channel optical system (CBC system), measuring at least one current optical property associated with the corresponding output beam, such as an intensity-related property (parameter value) of an interference signal of the corresponding output beam with at least a portion of the reference beam (step 52); determining a required / desired current OPL adjustment for each input light beam based on its corresponding measured at least one optical property and / or determining one or more required current control properties for controlling the corresponding OPL adjuster (step 53); adjusting the OPL of each optical fiber based on the determined latest OPL adjustment by controlling a corresponding OPL adjuster of each channel based on the determined latest desired control property (step 54); may include:

[0081] The above method steps for OPL adjustment may be performed in parallel for all channels of a CBC multi-channel optical system, with these steps 51-54 being performed continuously, recursively, recursively, in a closed-loop, continuous, or cyclical manner such that the OPL of all input optical beams of all optical channels of the CBC system are regularly measured / estimated and corrected in order to continuously mitigate / minimize the OPD associated with multiple beams.

[0082] OPL adjustments can be made, e.g. (i) controlling the length of one or more sections of one or more optical fibers through which each input or output light beam of the CBC system propagates by controlling the temperature of each corresponding fiber section using one or more temperature-controlled OPL regulators; and / or (ii) controlling the OPL of each optical beam of the CBC system by using an opto-mechanical adjuster configured to control the length of propagation of the optical beam by controlling one or more mechanical and / or opto-mechanical elements, such as using a plurality of reflectors, at least one of which has a mechanically controlled positioning, or using a fiber manifold (for each channel of the CBC system) with a plurality of controllable routing switches for selecting one of a plurality of optional paths made available by the fiber manifold and thereby controlling the length of fiber along which the corresponding input / output optical beam propagates; This may be done by any technique and / or type of regulator, such as by one or more of:

[0083] According to some embodiments, the method of FIG. 6 may include directing a portion of each output light beam of the CBC system to interfere with a corresponding portion of a reference light beam, such that measurements of at least one current optical property associated with each output beam indicate, for each channel of the CBC system, an intensity value of an interference signal of the interference between the portion of the output beam and the portion of the reference beam.

[0084] Reference is now made to Figure 7, which is a flow chart outlining a procedure / method for temperature-controlled fiber length adjustment on a channel-by-channel basis for OPL adjustment of multiple input light beams in a CBC system, including using a reference light beam for measuring and controlling the optical path difference (OPD) of a CBC channel, according to some embodiments. The method includes at least: Directing a plurality of input light beams through a corresponding plurality of optical fibers and CBC units to produce a plurality of output beams at NF (step 61); Splitting the output beam to form a first array of output beams propagating in a first propagation direction and a second array of output beams propagating in a second propagation direction that is angled from the first propagation direction (step 62); directing the reference beam to interfere with all beams of the second array of output beams to form an interference array of interference signals (step 63); measuring a current intensity-related characteristic for each interferometric signal in the interferometric array (step 64); determining a required / desired latest OPL adjustment or one or more required latest adjuster control properties for each OPL adjuster of each input light beam based on the latest intensity-related characteristics of its corresponding interference signal (step 65); (Optionally) if a required OPL adjustment has been determined, determining a required updated fiber temperature adjustment for each corresponding optical fiber based on the determined required / desired OPL of its corresponding light beam (step 66); adjusting the temperature of each fiber section according to its corresponding determined required current temperature adjustment (step 67); may include:

[0085] Steps 51-55 and 61-67 of the above-described method / procedure may be implementable using any one or more software and / or hardware computing, communication and control means, and may require predetermined (and optionally programmable) executable actions to perform at least some of the steps.

[0086] The methods described above in connection with FIGS. 5 and 6 may also include other CBC performance improvement related steps, such as adjusting the phase and / or polarization of the input beam.

[0087] The methods described above in connection with Figures 6 and 7 may also include an initial calibration test or procedure in which fiber lengths are matched as best physically possible to minimize channel OPD, and the OPL or OPD between each input beam and a similar / close reference beam interfering with each input beam is measured to determine a temperature gap value ΔTG used to increase or decrease the temperature of the optical fiber section to adjust the OPL and fiber length. The temperature gap value ΔTG determines how much the temperature increases or decreases with heating and cooling of each fiber section. This calibration procedure may also be used to determine the TAP for cooling and heating of a controllable temperature regulator. The calibration procedure may also include measuring the rate at which the OPL changes and / or exceeds a rate of change that adversely affects CBC performance.

[0088] The calibration procedure may be performed at a stable and constant ambient / environmental temperature (such as standard room temperature of 25 degrees Celsius) and / or at varying ambient / environmental temperatures and may be used to preset the temperature gap ΔTG values ​​and cooling and heating TAP values ​​for different ambient temperatures in order to adjust the processing and control programs used by the master controller in real time according to the actual ambient temperature as measured, for example, by a thermometer or any other temperature measurement means.

[0089] According to some embodiments, because the phase of an input light beam may change much faster than its OPL, and because the OPL adjustment may require a TAP that is much longer than the rate of change and adjustment of the phase, the OPL adjustment system and / or method may be programmed to adjust the OPL adjustment according to a pre-measured rate of change of the OPL and a TAP rate, as well as separately adjust according to a pre-measured or known rate of phase change.

[0090] According to other embodiments, each OPL adjuster of the multi-channel optical system may comprise an illuminator having one or more light sources and an additional fiber section connected to the optical fiber of each optical channel of the multi-channel optical system. In these embodiments, the OPL adjustment may be performed by irradiating at least a portion of the additional fiber section to heat it and extending the length of the additional fiber section to adjust the OPL of the light beam propagating through each optical fiber and the additional fiber section.

[0091] According to some embodiments, the additional fiber section may have certain known optical absorption characteristics that may differ from the optical fiber absorption characteristics used by the multi-channel optical system, such that an illuminator of the OPL adjuster is configured to emit light corresponding to the absorption characteristics of the additional fiber section, which is absorbed by the additional fiber section due to heating and thus expansion of the additional fiber section for OPL adjustment of the light beam passing through the optical fiber.

[0092] One or more lighting characteristics of the illuminator of the OPL adjuster may be controllable / adjustable. For example, the one or more lighting characteristics may be: the wavelength and / or wavelength bandwidth of the illumination; the intensity, power, amplitude, spatial distribution and / or flux of the illumination; Radiation opening, directionality of radiation propagation, the duration of irradiation, and / or One or more pulse characteristics It includes one or more of the following.

[0093] According to some embodiments, the additional fiber section is a doped optical fiber having at least one dopant with known optical absorption characteristics, and the illuminator of the OPL modulator is configured to emit light corresponding to the optical absorption characteristics of the doped additional fiber section.

[0094] Reference is now made to FIG. 8, which schematically illustrates a multi-channel optical system such as CBC system 200 that defines multiple light channels using an integrated detection and control subsystem 300 that includes an OPL adjustment subsystem 310 that includes multiple OPL adjusters 311, each of which includes at least one illuminator 312 and at least one additional fiber section 220 connected (spliced) or coupled to a respective optical fiber 221 of the fiber array 220 of the CBC system 200, and wherein the channel-by-channel OPL adjustment of each light beam of the multi-channel optical system may be based on heating (temperature control) of the additional fiber section 313 by irradiating it with its corresponding illuminator 312 according to one or more predetermined and / or one or more adjustable / controllable illumination characteristics, such as emission / radiation wavelength characteristics, pulse characteristics, illumination (light) intensity / amplitude and / or flux.

[0095] CBC System 200 is an illumination unit 210 configured to generate a plurality of input light beams having similar one or more optical properties, such as similar wavelengths (WL) or WL bandwidths, and direct them into a fiber array 220 of a plurality of optical fibers 221; a CBC unit 230 which may comprise at least one CBC array of CBC elements, such as a collimation array comprising an array of collimator lenses 231 and / or an array of beam shaping units, configured to combine input light beams and output a corresponding array of output light beams propagating substantially parallel to one another, thereby defining an optical axis "x" parallel to the direction of propagation of the output light beams; a detection and control subsystem 300, which may include parallel detection, analysis (processing), and adjustment of the OPL of each light beam propagating through at least the CBC system 200, and optionally adjustment of one or more additional beam characteristics, such as phase and / or polarization; may be provided.

[0096] According to some embodiments, the detection and control subsystem 300 includes: an OPL adjustment subsystem 310 comprising at least an array of OPL adjusters 311, where a corresponding OPL adjuster for each optical channel "i" is positioned and configured to adjust the OPL of a corresponding incident light beam for channel "i" of the CBC system, the OPL adjustment being based on illuminating a portion of a corresponding optical fiber 221; a reference unit 320 configured to generate and direct a reference light beam 12 having desired (and optionally controllable / adjustable) optical properties, such as a desired beam divergence, a desired energy / intensity distribution, a desired propagation direction, etc.; an optical setup comprising one or more optical elements and / or devices, such as a beam splitter 325, configured to sample a portion of each output light beam 11 output from the CBC unit 230, interfere with a corresponding portion of the reference light beam 12, thereby forming a corresponding interference signal 13, etc.; a detection unit 330 comprising an array of photodetectors 331, each positioned and configured to detect the current intensity / energy of a corresponding interference signal 13; a control unit 340 configured to receive and analyze (process) intensity-related latest data / signals from each photodetector 331 of the detection unit 330 for OPL adjustment of the corresponding input and / or output light beam of each channel "i" and to determine at least corresponding latest regulator control properties for controlling the illumination of the corresponding OPL regulator; may be provided.

[0097] The intensity or intensity-related values ​​of each interference signal 13 can be transmitted and received by the control unit 340, which processes / analyzes each intensity-related parameter value of all channels at any given moment to determine the required OPL adjustment and / or one or more related current adjuster control instructions / properties, such as the duration of illumination, the intensity / amplitude of the illuminating light, the spectral characteristics of the illumination, etc., to enable the best OPL adjustment by minimizing / mitigating the OPD between each output light beam 11 and the reference light beam 12 with which it interferes, thereby enabling the mitigation / minimization of the OPD between all output light beams 11 to flexibly change the CBC performance, such as PIB (spatial distribution of power in the FF transverse plane), energy loss, etc.

[0098] According to some embodiments, OPL modulation may be performed in parallel using parallel detection, analysis / processing and modulation procedures per channel such that all optical beams of all optical channels of the CBC system 200 are modulated parallel to each other.

[0099] According to some embodiments, each OPL adjuster 311 may comprise one or more illuminators, such as one or more light emitting diodes (LEDs), configured to illuminate the cladding of the additional fiber portion 313 and adjust the OPL of the light beam passing therethrough by expanding the light from the illuminators by absorbing it in the cladding of the additional fiber portion 313 of the OPL adjuster 311.

[0100] Each illuminator may be configured to emit / irradiate light with one or more spectral characteristics, such as a specific wavelength (WL) or narrow WL bandwidth, corresponding to the absorption characteristics of the additional fiber section or portion thereof, such as light with a specific WL or narrow WL bandwidth tuned to be effectively absorbed by the core and / or cladding material of the optical fiber to directly heat the additional fiber section 313. For example, the additional fiber section 313 or a portion thereof, such as its cladding, may be doped with a dopant such as Tm (thulium), where the dopant has a specific absorption line, and an illuminator 312 emitting light of this specific absorbable wavelength may be used. For example, for illumination of a Tm-doped fiber, a narrow WL band with a peak at 793 nm of illumination may be used to increase / maximize or improve absorption, thereby rapidly and effectively heating the additional fiber section 313 with an intensity / fluence tuned to provide effective and rapid heating, but without adversely affecting the optical or other properties of the input light beam propagating through the additional fiber section 313 and / or irreversibly damaging the cladding and / or core of the optical fiber.

[0101] Illumination of the additional fiber portion 313 can be performed externally to the additional fiber portion 313 from its outer surface (e.g., by contacting the additional fiber portion 313 or illuminating a cross section of the additional fiber portion 313), or by coupling the light source (illuminator 312) of the OPL adjuster 311 to the additional fiber portion 313 so that light emitted from the illuminator 312 propagates through the fiber and is gradually absorbed throughout at least a portion of the length of the additional fiber portion 313.

[0102] The temperature may be controlled by controlling one or more illumination characteristics of the irradiating light with the OPL adjuster 311, such as the amplitude / intensity, flux and / or spatial intensity distribution of the irradiating light, duration of irradiation, aperture, directionality of radiation propagation, or by adjusting the temperature using a pulsed light source by adjusting the number of pulses, the duration of each pulse, the energy distribution characteristics of each pulse, and / or the duty cycle of the pulses.

[0103] Each OPL regulator 311 may comprise one or more illuminators of the same or different type and / or optical properties of illumination, such as light emitting diodes (LEDs), diode lasers, flash lamps, quantum cascade lasers (QCLs), or any other light source.

[0104] According to some embodiments, the optical fiber 221 may be undoped or may be doped with a dopant different from that of the additional fiber section 313, so that light of a certain wavelength intended to heat and expand the length of the additional fiber section 313 does not also expand other nearby / adjacent sections of the optical fiber 221. For example, the optical fiber 221 may be a Yb-doped amplifying fiber doped with a dopant of ytterbium, while the additional fiber section 313 is doped with thulium (Tm) as described above, such that an input light beam of about 1060 nm (nanometers) will not be absorbed as well by the additional fiber section 313.

[0105] According to some embodiments, the control unit 340 may be configured to receive latest intensity-related data from each photodetector 331 of the detection unit 330, indicating the current / latest intensity of the interference signal 13 of each channel, and based thereon, and optionally based on a comparison between the latest received intensity-related data and one or more previous measurements, determine whether an OPL adjustment is required for the corresponding light beam and determine a control action (latest adjuster control properties) for the required OPL adjustment, such as the required irradiation duration, flux and / or intensity, and control the corresponding illuminator 312 of the corresponding OPL adjuster 311 in accordance with the determined latest adjuster control properties.

[0106] To determine the required additional amount of OPL ΔOPL, the control unit 340 may be configured to determine a value of the required additional amount of OPL ΔOPL based on the latest intensity-related data received from the corresponding photodetector 331, and to determine the latest required regulator control property based on the determined additional amount of OPL ΔOPL.

[0107] The regulator control properties may include one or more control commands / actions and / or one or more controllable / adjustable illumination properties of the corresponding illuminator 312, such as the operating mode, duration of illumination, etc.

[0108] According to some embodiments, one or more other optical parameters of the light beam propagating through the CBC system 200 may require adjustment and correlation in the form of parallel feedback loops for phase, spatial distribution of power / intensity, spatial distribution of phase, polarization orientation, etc. for best CBC and FF performance, requiring one or more additional adjuster / controller arrays, such as a phase adjuster array 370 comprising multiple phase adjusters 371, each also positioned and configured to fix the phase of that particular light beam based on the same measured intensity-related parameter of the interference signal 13 detected by the photodetector 331 of the corresponding optical channel.

[0109] Thus, the same reference unit 320, optical mechanism (e.g., beam splitter 325), detection unit 330, and same detector array of the same control unit 340 may be used to detect and adjust multiple properties of the multi-channel light beam of the CBC system 200 in parallel, including OPL and OPD, phase, phase distribution, energy / intensity distribution, polarization, etc., all adjusted in parallel and relative to each other based on the detected intensity of the interference signal interfering with the same reference light beam 12, and optionally based on where each such property, such as OPL, phase, etc., is fixed when an ultimate (maximum or minimum) interference signal intensity is achieved.

[0110] According to another embodiment, each OPL adjuster may include an illuminator configured to externally illuminate a portion of the optical fiber 221 of the CBC system 200 .

[0111] 9 illustrates, in accordance with some embodiments, the main general steps of a method / procedure for OPL modulation in a CBC system using an array of OPL modulators based on irradiation-based heating of each optical fiber of the CBC system. directing a plurality of input light beams of a CBC system through a corresponding plurality of optical fibers and a CBC unit to produce a plurality of output beams in a near-field (NF) region of the CBC system (step 71); interfering a portion of each output light beam with a corresponding portion of a reference beam (step 72); For each optical channel in the CBC system, measuring (step 73) a current intensity-related characteristic (parameter value) of the interference signal of the output beam with the corresponding portion of the reference beam; determining a required / desired current OPL adjustment for each input light beam based on at least its corresponding intensity-related characteristic of the interference signal, and determining one or more required OPL adjuster control actions, including, for example, duration of illumination, intensity / power / amplitude, pulse characteristics, etc. (step 74); adjusting the OPL of each optical fiber based on the determined latest OPL adjustment by controlling a corresponding OPL adjuster of each channel to irradiate one or more fiber segments of the optical fiber of each optical channel to heat the fiber segments and expand the fiber length by an additional length ΔL (step 75); Includes:

[0112] According to other embodiments, the OPL of each light beam may be adjustable using other OPL adjustment techniques that are not necessarily related to temperature control of heating and / or cooling the fiber.

[0113] One such technique allows for the selection of one of several paths for a passing light beam made available by an OPL adjuster.

[0114] Reference is now made to Figure 10, which shows a schematic of a router OPL adjuster 510 for a multi-channel optical system. The router OPL adjuster 510 may be implemented as a photonic chip with multiple light guides (not necessarily optical fibers) arranged as a manifold / cascade.

[0115] For example, router OPL adjuster 510 may comprise a manifold of routing fibers F1-F20 connectable to one another by routing switches S1-S14. Router OPL adjuster 510 may have an input port 511 for receiving an input light beam passing therethrough and an output port 512 for outputting the light beam after being routed through a selected path associated with a selected OPL. Routing switches S1-S14 may be controllably turned on or off to set a selected OPL addition amount ΔOPL according to system requirements.

[0116] For example, if the length of an optical fiber in a CBC system has an initial length "L" at room temperature and the required OPL adjustment is to add an additional length of ΔOPL, a controller of the system / OPL adjustment subsystem may calculate the required ΔOPL value and, based on the value of ΔOPL, determine / select the required routing fiber from routing fibers F1-F20 that provides such fiber length. For example, for a particular ΔOPL of value d, the required additional fiber length may be ΔL, which can be routed by selecting / routing the optical beam to pass through routing fibers F1-F2-F6-F14-F18-F20, which in this case represents the shortest path between input port 511 and output port 512. The routing is controlled by controlling the state of the switches. Following the above example of selected shortest path lengths, routing switch S1 is set to route the incoming light beam from input port 511 to routing fiber F2, routing switch S3 is set to route the light beam from fiber F2 to fiber F6, routing switch S7 is set to route the light beam from fiber F6 to fiber F14, routing switch S11 is set to route the light beam from fiber F14 to fiber F18, and routing switch S13 is set to route the light beam from fiber F20 to output port 312. Each of routing switches S1-S14 is thus configured to allow controllable routing switching between two states, with each switch state routing the light beam via a different light guide / fiber (out of two in this example).

[0117] Please state the routing switch timing / duration for the maximum number of routing switches relative to the required OPL fixed timing / duration per channel.

[0118] According to yet another embodiment, the OPL of the light beam may be controllably adjusted using one or more reflectors, and the length of the OPL may be controlled by controlling the angular orientation of the trajectory of the light beam, for example, by controlling the positioning of the one or more reflectors and / or by controlling the angle of incidence of the light beam into a lumen in which the reflector is movably or fixedly mounted.

[0119] 11 shows an exemplary OPL adjuster 410 comprising multiple reflectors, such as a first reflector 411 and a second reflector 412, positioned opposite each other and at an angle relative to a light source 401 from which a light beam radiates and enters the OPL adjuster 410. One or more of the reflectors 411 / 412 may be controllably movable / rotatable / positionable by one or more actuators, such as a first actuator 411A configured to control and adjust the positioning of the first reflector 411 and a second actuator 412A configured to control and adjust the positioning of the second reflector 412, e.g., comprising a micro electromechanical system (MEMS) with micromotors and movable elements. The total length of the light beam inside the OPL adjuster 410 (its lumen) is determined by the directionality of each portion of the light beam as it propagates through the OPL adjuster 410, which is set by the positioning (tilt orientation and location) of each of its reflectors 411, 412 relative to the directionality of the light beam as it enters the OPL adjuster and relative to the positioning of the input face of, e.g., optical fiber 420, of the multi-channel optical system.

[0120] According to some embodiments, the direction of the incident light beam may be controllable by controlling a light source (LS) actuator 402 configured to control at least the directionality of the light when emitted from the LS.

[0121] A single controller 450 may control all actuators 402, 411A, and / or 412A based on one or more measured characteristics of the light beams of the multi-channel optical system, such as, for example, the intensity of the interference signal. As noted above, for the other described types of OPL adjustment, OPL adjustment for all channels of the multi-channel system, as well as detection and processing / analysis, may occur in parallel and separately for each channel.

[0122] Reference is now made to Figure 12, which shows a schematic illustration of the main steps of a procedure / method for OPL fixation in a CBC system using an array of path-directing (optomechanical) OPL adjusters, according to some embodiments. The method comprises: directing a plurality of input light beams of the CBC system through a corresponding plurality of optical fibers and a CBC unit to produce a plurality of output beams in a near-field (NF) region of the CBC system (step 81); interfering a portion of each output light beam with a corresponding portion of a reference beam, thereby generating an (array of) a plurality of corresponding interference signals (step 82); For each optical channel in the CBC system, measuring a current intensity-related characteristic (parameter value) of the corresponding interfering signal corresponding to channel "i" (step 83); Determining the latest required / desired OPL adjustment and / or associated required routing and routing control actions (current regulator control properties) (step 84); adjusting the OPL of each light beam based on the determined required latest OPL adjustment and / or associated required routing and routing control actions (step 85), for example by controlling the switching state of each of one or more routing switches of the routing OPL adjuster, or by controlling the positioning of at least one reflector or the propagation direction of light passing through or generated by the routing OPL adjuster; may be provided.

[0123] Examples Example 1 is a detection and control subsystem for a multi-channel optical system comprising at least one fiber array of optical fibers, thereby guiding a plurality of light beams through its waveguide units defining an array of optical channels, comprising: (i) an optical path length (OPL) adjustment subsystem comprising an array of OPL adjusters each constructed and arranged to controllably adjust an optical beam OPL of each optical channel of the multi-channel optical system; (ii) for each optical beam of each optical channel of the multi-channel system, at least receiving one or more current detected characteristics associated with the light beam; analyzing the received one or more characteristics to determine one or more updated adjuster control properties required to achieve the desired associated OPL adjustment of the light beam; Controlling the OPL adjusters of the optical channels to adjust the OPL of the light beam according to the determined one or more latest adjuster control properties, wherein the detection, analysis, and OPL adjustment are performed in parallel for all optical channels of the multi-channel optical system. at least one control unit configured to a detection and control subsystem comprising at least:

[0124] In Example 2, the subject matter of Example 1 may include the matter that the multi-channel optical system is a coherent beam combining (CBC) system, and the OPL adjustment is performed to reduce the optical path difference (OPD) between the light beams of the CBC system.

[0125] In Example 3, the subject of Example 2 is a CBC system that has at least (i) an illumination unit comprising one or more light sources configured to generate an array of input light beams of similar optical properties; (ii) a CBC unit comprising one or more CBC elements configured to combine an array of input light beams to form a corresponding array of output light beams propagating parallel to one another and defining optical axes parallel to their directions of propagation; (iii) a waveguiding unit comprising at least one array of optical fibers configured to guide the array of input light beams to the CBC unit; This may include the matter of having the above.

[0126] In Example 4, the subject of Example 3 is further characterized in that the detection and control subsystem: a reference unit configured to generate or sample and direct a reference light beam; an optical arrangement comprising one or more optical elements configured to direct the array of output light beams such that a first portion of each light beam is directed along the optical axis and a second portion of each light beam is directed in a propagation direction other than the propagation direction of the optical axis to interfere with a corresponding portion of the reference light beam and generate a corresponding interference signal, thereby forming an array of interference signals; a detection unit configured to separately detect at least the intensity of each interference signal and output corresponding latest intensity-related data, and a control unit configured to receive and analyze the latest intensity-related data of each interference signal of each optical channel in parallel to determine one or more required latest adjuster control properties and control each OPL adjuster in parallel according to the determined latest adjuster control properties to achieve associated OPL adjustment of the corresponding optical beam; The present invention may further include the following.

[0127] In Example 5, the subject of Example 4 is: - the overall strength of the corresponding interfering signal, - the main peak of the beam profile of the corresponding interference signal, - the total intensity of the main lobe of the beam profile of the corresponding interference signal, It may include the item indicating one or more of the following.

[0128] In Example 6, the subject matter of any one or more of Examples 4 and 5 may include the control unit analyzing the most recent intensity-related data received for each interference signal by comparing its value with a predetermined reference value or one or more values ​​of one or more previous consecutive measured interference signals of the same corresponding optical channel.

[0129] In Example 7, the subject of any one or more of Examples 4-6, wherein the detection and control subsystem: a phase locking unit comprising at least one array of phase adjusters each configured to shift the phase of an input light beam of a corresponding optical channel; a polarization fixation unit comprising at least one array of polarizers, each configured to adjust the polarization of an input light beam of a corresponding optical channel; a beam steering unit configured to perform controllable beam steering by controlling the relative phase between the input light beam or the output light beam; wherein the phase and / or polarization fixing and / or beam steering is performed based on the detected intensity of each interference signal.

[0130] In Example 8, the subject matter of any one or more of Examples 1-7 may include, where each corresponding OPL adjuster of each optical channel comprises at least one optical path determination unit configured to direct an incident optical beam to pass through one optical path from a plurality of selectable optical paths of the at least one optical path determination unit in the OPL adjuster, and the one or more latest adjuster control properties are related to a latest selection of a particular optical path.

[0131] In Example 9, the subject matter of Example 8 may include each optical routing unit of the OPL adjuster comprising a fiber manifold comprising a manifold of routing optical fibers, at least some of the routing optical fibers being connected to one or more other routing optical fibers of the fiber manifold by one or more controllable routing switches, and controlling the state of each of the one or more controllable routing switches to set and select a particular optical path that is a particular OPL addition amount ΔOPL to the OPL of the light beam propagating through the corresponding optical fiber of each channel.

[0132] In Example 10, the subject matter of Example 9 may include the fiber manifolds being configured in a cascade configuration such that at least one of the controllable routing switches is operatively associated with at least two other controllable routing switches.

[0133] In Example 11, the subject matter of Example 8 may include the matter that each path determination unit of each OPL adjuster comprises at least two reflectors configured to control the OPL addition amount Δ by adjusting the positioning of at least one of the reflectors therein and / or by adjusting the direction of the light beam as it enters the path determination unit.

[0134] In Example 12, the subject matter of Example 11 may include the matter that at least one of the reflectors is operated by a controllable actuator comprising at least one motor and at least one movable element to controllably adjust the positioning of the reflector.

[0135] In Example 13, the subject of any one or more of Examples 8-12, wherein at least one control unit: For each optical channel determining an appropriate OPL addition ΔOPL for each optical channel relative to the OPL of the light beam propagating through the corresponding optical fiber; selecting an appropriate optical routing state for each OPL adjuster corresponding to the determined OPL addition amount ΔOPL; Controlling at least one optical path determining unit of an OPL adjuster of the optical channel according to the selected optical path. The present invention may include the matter of being configured as follows.

[0136] In Example 14, the subject matter of any one or more of Examples 1-7 may include an aspect where each OPL adjuster is configured to control a temperature of at least one fiber portion of a corresponding optical fiber of a fiber array of the multi-channel optical system to adjust a length of the optical fiber of the corresponding fiber array of the multi-channel optical system.

[0137] In Example 15, the subject matter of Example 14 may include each OPL adjuster configured to either actively heat a respective heat conduction element of the OPL adjuster and allow only natural passive cooling of the heated optical fiber portion via natural heat dissipation, or to actively heat and actively cool a respective heat conduction element of the OPL adjuster.

[0138] In Example 16, the subject matter of any one or more of Examples 14 and 15 may include wherein each OPL adjuster comprises at least one heat conducting element coupled to a corresponding fiber portion of an optical fiber of the multi-channel optical system, the heat conducting element being at least controllably heated to extend the length of the corresponding optical fiber and thus extend the OPL of the corresponding light beam passing through the optical fiber.

[0139] In Example 17, the subject of Example 16 is characterized in that each heat conducting element is: a wire or strap wrapped around the outer surface of each fiber section; or A raised heat-conducting element with optical fiber wrapped around it This may include the matter of having the above.

[0140] In Example 18, the subject matter of any one or more of Examples 14 and 15 may include the fact that each heat conducting element is raised and coupled to a corresponding optical fiber using one or more attachment or coupling means or by wrapping the corresponding optical fiber around the raised heat conducting element.

[0141] In Example 19, the subject matter of Example 14 can include wherein each controllable temperature regulator comprises a thermoelectric cooler for actively heating and cooling at least one fiber portion.

[0142] In Example 20, the subject matter of any one or more of Examples 14-19 may include the OPL adjustment subsystem further comprising a sensor array including a plurality of temperature sensors, each installed and configured to measure a temperature near a temperature control zone of a corresponding optical fiber of a corresponding optical channel, and the OPL adjusters are installed correspondingly, and each OPL adjustment is made based on the measured current temperature of the corresponding temperature control zone of the corresponding optical fiber.

[0143] In Example 21, the subject matter of Example 14 may include the matter of the OPL adjuster comprising at least one illuminator configured to illuminate a corresponding fiber portion of a corresponding optical fiber of each optical channel associated with the OPL adjuster by illuminating the fiber portion.

[0144] In Example 22, the subject matter of Example 21 may include the matter that at least one illuminator is positioned outside its corresponding fiber section, and each illuminator is configured to emit light at one or more wavelengths or wavelength bands corresponding to the spectral absorption characteristics of at least a portion of the fiber section to be illuminated.

[0145] In Example 23, the subject matter of any one or more of Examples 21 and 22 may include that at least one illuminator is configured and arranged such that light emitted therefrom propagates at an angle relative to the propagation direction of a light beam propagating through a corresponding fiber section, forming a non-zero angle between the propagation direction of the light beam and the propagation direction of light emitted from the at least one illuminator.

[0146] In Example 24, the subject matter of Example 14 may include the matter where each OPL adjuster comprises an illuminator having one or more light sources and an additional fiber section connected to the optical fiber of each optical channel of the multi-channel optical system, and the illuminator is installed and configured to irradiate at least a portion of the additional fiber section to heat it and extend the entire length of the additional fiber section to adjust the OPL of the light beam propagating through each optical fiber and the additional fiber section.

[0147] In Example 25, the subject matter of Example 24 may include the matter where the additional fiber section is a doped optical fiber having at least one dopant with known optical absorption characteristics, and the illuminator of the OPL adjuster is configured to emit light corresponding to the optical absorption characteristics of the additional fiber section.

[0148] In Example 26, the subject matter of Example 25 can include the matter where the illuminator of the OPL adjuster is coupled to an additional fiber section to illuminate a cladding portion of the additional fiber section.

[0149] In Example 27, the subject matter of any one or more of Examples 25 and 26 may include the matter that the additional fiber section is doped with a thulium (Tm) dopant.

[0150] In Example 28, the subject matter of any one or more of Examples 25-27 may include each optical fiber of the multi-channel optical system having different light absorption characteristics than each additional fiber section.

[0151] In Example 29, the subject matter of any one or more of Examples 21-28 may include at least one illuminator configured such that one or more lighting characteristics thereof are controllable.

[0152] In Example 30, the subject of Example 29 is configured to: the wavelength and / or wavelength bandwidth of the illumination; the intensity, power, amplitude, spatial distribution and / or flux of the illumination; Radiation opening, directionality of radiation propagation, The duration of irradiation, One or more irradiation pulse characteristics It may include one or more of the following.

[0153] Example 31 is a method for adjusting an optical path length (OPL) of a multi-channel optical system using a fiber array of a plurality of optical fibers for respectively guiding a plurality of light beams passing therethrough to define a corresponding array of optical channels, the method comprising: providing an OPL adjustment subsystem comprising at least one array of OPL adjusters each configured to at least adjust an OPL of each light beam of the multi-channel optical system; providing a control unit configured to process the received data and control at least each OPL regulator; For each optical channel, detecting, using a detection unit, one or more current optical characteristics associated with the light beam of each optical channel output from the multi-channel optical system; analyzing the received one or more characteristics of the optical beam of each optical channel to determine, with a control unit, one or more current adjuster control properties each associated with a required current OPL adjustment for the optical beam propagating through each optical channel; and adjusting, with the control unit, the OPL of each light beam by controlling each OPL adjuster according to the determined one or more latest adjuster control properties, wherein the detection, analysis, and OPL adjustment are performed in parallel for all optical channels of the multi-channel optical system. It is a method.

[0154] In Example 32, the subject matter of Example 31 may include the matter that the multi-channel optical system is a coherent beam combining (CBC) system and the OPL adjustment is performed to reduce the optical path difference (OPD) between the light beams of the CBC system.

[0155] In Example 33, the subject of Example 32 is (i) generating an array of input light beams of similar optical properties using an illumination unit of a multi-channel optical system; (ii) using a CBC unit of the multi-channel optical system, combining the array of input light beams to form a corresponding array of output light beams that propagate parallel to one another and define optical axes parallel to their own propagation directions; (iii) guiding the array of input light beams to the CBC unit using a waveguiding unit comprising at least one fiber array comprising a plurality of optical fibers; It may further include the matter of including.

[0156] In Example 34, the subject of any one or more of Examples 31-33 comprises a method generating or sampling and directing a reference light beam; directing an array of output light beams, with a first portion of each light beam directed along the optical axis and a second portion of each light beam directed in a propagation direction other than the propagation direction of the optical axis to interfere with a corresponding portion of the reference light beam and generate a corresponding interference signal, thereby forming an array of interference signals; The control unit is configured to separately detect at least the intensity of each interference signal and output corresponding latest intensity-related data, and the control unit receives and analyzes the latest intensity-related data of each interference signal of each optical channel in parallel to determine one or more latest required adjuster control properties to achieve the associated OPL adjustment of the corresponding optical beam, and controls each OPL adjuster in parallel according to the determined latest adjuster control properties. It may further include the matter of including.

[0157] In Example 35, the subject of Example 34 receives the corresponding most recent intensity-related data for each interference signal, - the overall strength of the corresponding interfering signal, - the main peak of the beam profile of the corresponding interference signal, - the total intensity of the main lobe of the beam profile of the corresponding interference signal, It may include the item indicating one or more of the following.

[0158] In Example 36, the subject matter of any one or more of Examples 34 and 35 may include the matter that the most recently received intensity-related data of each interference signal is analyzed by comparing its value with a predetermined reference value or one or more values ​​of one or more previous consecutive measured intensity-related values ​​of interference signals of the same corresponding optical channel.

[0159] In Example 37, the subject of any one or more of Examples 34-36 is the method comprising: adjusting the phase of each input optical beam of each optical channel using a phase locking unit comprising an array of phase adjusters; adjusting the polarization of each input light beam of each optical channel using a polarization fixing unit comprising at least one array of polarizers; Controlling the relative phase between the input light beam or the output light beam to control the beam steering of the output light beam; wherein the phase and / or polarization fixing and / or beam steering is performed based on the detected intensity of each interference signal.

[0160] In Example 38, the subject matter of any one or more of Examples 31-37 may include the matter that the OPL adjustment of each optical channel is performed by directing the incoming optical beam to pass through one optical path from a plurality of selectable optical paths made available by the OPL adjuster, and the one or more latest adjuster control properties relate to the latest selection of the particular optical path.

[0161] In Example 39, the subject matter of Example 38 may include routing an incoming light beam using an OPL adjuster comprising a fiber manifold comprising a manifold of routing optical fibers, at least some of the routing optical fibers being connected to one or more other routing optical fibers of the fiber manifold by one or more controllable routing switches, and controlling the state of each of the one or more controllable routing switches to set and select a particular optical path that is a particular OPL addition ΔOPL to the OPL of the light beam propagating through the corresponding optical fiber of each channel.

[0162] In Example 40, the subject matter of Example 38 may include the matter that routing of the light beam is performed by an OPL adjuster comprising at least one routing unit, each routing unit comprising at least two reflectors configured to control the OPL addition amount Δ by adjusting the positioning of at least one of the reflectors and / or by adjusting the direction of the light beam as it enters the routing unit.

[0163] In Example 41, the subject of any one or more of Examples 38-40 is the method comprising: For each optical channel, determining an appropriate OPL addition ΔOPL to the OPL of the light beam propagating through the corresponding optical fiber for each optical channel; selecting an appropriate optical routing state for each OPL adjuster corresponding to the determined OPL addition amount ΔOPL; controlling at least one optical path determining unit corresponding to each OPL adjuster according to the selected optical path; It may further include the matter of including.

[0164] In Example 42, the subject matter of any one or more of Examples 31-37 may include the matter where the OPL adjustment is performed by controlling a temperature of at least one fiber portion of a corresponding optical fiber of a fiber array of the multi-channel optical system to adjust a length of the optical fiber of the corresponding fiber array of the multi-channel optical system, and each OPL adjuster is configured to heat at least one or more fiber portions of the corresponding optical fiber of the multi-channel optical system.

[0165] In Example 43, the subject matter of Example 42 may include each OPL adjuster configured to either actively heat a respective heat conduction element of the OPL adjuster and allow only natural passive cooling of the heated optical fiber portion via natural heat dissipation, or to actively heat and actively cool a respective heat conduction element of the OPL adjuster.

[0166] In Example 44, the subject matter of any one or more of Examples 42 and 43 may include the matter where each OPL adjuster comprises an illuminator having one or more light sources and an additional fiber section connected to the optical fiber of each optical channel of the multi-channel optical system, and the OPL adjustment is performed by irradiating at least a portion of the additional fiber section to heat it and extending the entire length of the additional fiber section to adjust the OPL of the light beam propagating through each optical fiber and the additional fiber section.

[0167] In Example 45, the subject of Example 44 is configured such that one or more lighting characteristics of the illuminator of the OPL adjuster are controllable, the one or more lighting characteristics being: the wavelength and / or wavelength bandwidth of the illumination; the intensity, power, amplitude, spatial distribution and / or flux of the illumination; Radiation opening, directionality of radiation propagation, The duration of irradiation, One or more pulse characteristics It may include one or more of the following.

[0168] In Example 46, the subject matter of any one or more of Examples 44 and 45 may include the additional fiber section being a doped optical fiber having at least one dopant with known optical absorption characteristics, and the illuminator of the OPL adjuster being configured to emit light corresponding to the optical absorption characteristics of the additional fiber section.

[0169] In Example 47, the subject matter of any one or more of Examples 44-46 may include an illuminator of the OPL adjuster being connected to an additional fiber section to illuminate a cladding portion of the additional fiber section.

[0170] In Example 48, the subject matter of Example 43 may include the matter where the temperature control is performed by irradiating a fiber portion of each optical fiber of the multi-channel optical system, and the OPL adjuster comprises at least one illuminator configured to heat a corresponding fiber portion of a corresponding optical fiber of each optical channel associated with the OPL adjuster by irradiating the fiber portion.

[0171] In Example 49, the subject matter of Example 48 may include that at least one illuminator is configured and arranged such that light emitted therefrom propagates at an angle relative to the propagation direction of the light beam propagating through the corresponding fiber section, forming a non-zero angle between the propagation direction of the light beam and the propagation direction of the emitted heating light.

[0172] In Example 50, the subject matter of any one or more of Examples 48 and 49 may include at least one illuminator configured such that one or more lighting characteristics thereof are controllable.

[0173] In Example 51, the subject of Example 50 is configured such that one or more lighting characteristics are: the wavelength and / or wavelength bandwidth of the illumination; the intensity, power, amplitude, spatial distribution and / or flux of the illumination; Radiation opening, directionality of radiation propagation, The duration of irradiation, One or more irradiation pulse characteristics It may include one or more of the following.

[0174] In Example 52, the subject matter of any one or more of Examples 42-51 further includes the method further comprising measuring a temperature near a temperature control zone of each optical fiber using a sensor array comprising a plurality of temperature sensors, each temperature sensor positioned and configured to sense a temperature of a fiber portion of the optical fiber of a particular optical channel in a temperature control zone corresponding to the OPL adjuster; This may include the matter that the required temperature adjustment for each OPL adjustment is made based on the measured current temperature of the corresponding temperature controlled section of the corresponding optical fiber.

[0175] An additional or alternative aspect of the disclosed embodiments relates to an OPL adjuster for adjusting the OPL of a light beam passing through an optical fiber, wherein the OPL adjustment is based on temperature control of one or more fiber sections of the optical fiber or additional fiber sections connected thereto.

[0176] An additional or alternative aspect of the disclosed embodiments relates to an OPL adjuster for adjusting the OPL of a light beam passing through an optical fiber, where the OPL adjustment is based on routing the light beam through one or more selectable optical paths.

[0177] While the above description discloses a limited number of exemplary embodiments of the present invention, these embodiments should not be construed as any limitation on the scope of the invention, but rather as illustrative of some of the ways in which the invention may be practiced.

[0178] The methods and / or procedures described herein may be implemented using any one or more software and / or hardware modules, devices, systems, methods, algorithms, processors, etc., which may be controllable and / or programmable.

[0179] Systems, modules, units, devices, etc. or portions thereof can be programmed to perform particular functions in response to computer-readable, executable instructions, rules, conditions, etc. from programmable hardware and / or software-based execution modules capable of implementing one or more of the methods or procedures disclosed herein, and thus can be considered to effectively disclose a separate "special-purpose computer" for each disclosed method / procedure embodiment.

[0180] The computer-readable and executable instructions may also be loaded into a computer, other programmable data processing apparatus, or other device that causes a series of operational steps to be performed on a computer, other programmable apparatus, or other device to generate a computer-implemented process, such that the instructions operating on the computer, other programmable apparatus, or other device perform the functions / operations specified in the flow charts and / or block diagrams or blocks.

[0181] In the above disclosure, unless otherwise stated, the words "substantially," "about," approximately, etc., defining a condition or relationship characterizing one or more features of an embodiment of the present invention should be understood to mean that the condition or characteristic is defined within an acceptable tolerance by operation of the embodiment of the present application for which the embodiment is intended.

[0182] It is important to note that the methods / procedures and / or systems / devices / subsystems / apparatus, etc. disclosed in the above specification are not strictly limited to the flowcharts and / or diagrams set forth in the drawings. For example, the methods may include additional or fewer procedures or steps compared to those depicted in the figures. Additionally, the method embodiments are not necessarily limited to the chronological order as shown and described herein.

[0183] The terms "processing," "computing," "calculating," "desiring," "determining," "ascertaining," "analyzing," "verifying," "estimating," "deriving," "selecting," "inferring," "identifying," "detecting," and the like may refer to operations and / or procedures of a computer, computing platform, computing system, or other electronic computing device that manipulate data represented as physical quantities (e.g., electronic or optical signals) in the computer's registers and / or memory and / or transform that data into other data similarly represented as physical quantities in the computer's registers and / or memory or other information storage medium capable of containing instructions for performing an operation and / or process.

[0184] Words used in the singular include plural coverage unless expressly stated otherwise or the context otherwise requires.

[0185] In the description and claims of this application, the verbs "comprise," "include," and "have," as well as their conjugations, are used to indicate that the subject of the verb does not necessarily completely recite the components, elements, features, functions, or portions of the subject of the verb.

[0186] Unless otherwise stated, the term "and / or" between the last two elements of a list of alternatives indicates that selecting one or more of the listed alternatives is appropriate and possible, i.e., all possible combinations of one or more of the specified alternatives are possible. Furthermore, the term "and / or" can be used interchangeably with the terms "at least one of," "any one of," or "one or more of," following a list of various alternatives.

[0187] Some features of the invention are described in the context of separate embodiments or examples for clarity, but may also be provided in combination in a single embodiment. Conversely, various features of the invention are described in the context of a single embodiment, example, and / or option for brevity, but may also be provided separately or in any suitable subcombination, or as suitable in any other described embodiment, example, or option of the invention. Some features described in the context of various embodiments, examples, and / or optional implementations should not be considered essential features of those embodiments, unless the various embodiments, examples, and / or optional implementations would not operate without those elements.

[0188] The number of elements shown in the figures should not be construed as limiting in any way, but is for illustrative purposes only.

Claims

1. A detection and control subsystem for a multi-channel optical system, comprising at least one fiber array of optical fibers, which guides multiple optical beams by its own guide unit that thereby defines an array of optical channels, (i) An OPL adjustment subsystem comprising an array of OPL adjusters, each configured and installed to controllably adjust the optical path length (OPL) of the optical beam of each optical channel of the multi-channel optical system, (ii) For each optical beam of each optical channel of the multi-channel system, at least Receiving one or more of the latest characteristics detected related to the light beam, By analyzing one or more of the received characteristics, one or more of the necessary state-of-the-art tuner control properties are determined to achieve the desired associated OPL tuning of the light beam. The OPL tuner of the optical channel is controlled to adjust the OPL of the light beam according to the determined one or more of the latest tuner control properties, and the detection, analysis, and OPL adjustment are performed in parallel for all optical channels of the multi-channel optical system. A control unit configured as follows: A detection and control subsystem comprising at least the following:

2. The detection and control subsystem according to claim 1, wherein the multi-channel optical system is a coherent beam coupling (CBC) system, and the OPL adjustment is performed to reduce the optical path difference (OPD) between the light beams of the CBC system.

3. The CBC system is at least, (i) an illumination unit comprising one or more light sources configured to generate an array of input light beams having similar optical properties, (ii) A CBC unit comprising one or more CBC elements, configured to combine the arrays of input light beams to form a corresponding array of output light beams that propagate parallel to each other and define an optical axis parallel to its own propagation direction, (iii) A waveguide unit comprising at least one array of optical fibers configured to guide the array of input optical beams to the CBC unit. The detection and control subsystem according to claim 2, comprising:

4. A reference unit configured to generate, sample, and guide a reference light beam, An optical mechanism comprising one or more optical elements, configured to guide an array of output light beams such that a first portion of each light beam is guided along the optical axis and a second portion of each light beam is guided in a propagation direction different from the propagation direction of the optical axis, interfering with a corresponding portion of the reference light beam, generating a corresponding interference signal, thereby forming an array of interference signals; It is configured to separately detect at least the intensity of each interference signal and output the corresponding latest intensity-related data. The control unit is configured to receive and analyze the latest intensity-related data output from each interference signal of each optical channel in parallel to achieve the relevant OPL tuning of the light beam, determine the necessary one or more latest tuner control properties, and control each OPL tuner in parallel according to the determined latest tuner control properties, and the detection unit is configured to do so. A detection and control subsystem according to any one of claims 1 to 3, further comprising:

5. The latest intensity-related data corresponding to each interference signal is: - The total intensity of the corresponding interference signal, - The main peak of the beam profile of the corresponding interference signal, - The overall intensity of the main lobe of the beam profile of the corresponding interference signal, The detection and control subsystem according to claim 4, wherein one or more of the above are represented.

6. The control unit receives at least one of the latest intensity-related data for each interference signal and values ​​its value Default baseline value, or One or more previously measured values ​​of one or more consecutive interference signals from the same optical channel The detection and control subsystem according to claim 4, which is analyzed by comparison with the following.

7. A phase-fixing unit comprising at least one array of phase adjusters, each configured to shift the phase of the input light beam of a corresponding optical channel, A polarization fixing unit comprising at least one array of polarizers, each configured to adjust the polarization of the input light beam of a corresponding optical channel, and / or A beam steering unit configured to perform controllable beam steering by controlling the relative phase between the input light beam or the output light beam. It further comprises at least one of the following: The detection and control subsystem according to claim 4, wherein the fixing of the phase and / or polarization and / or the beam steering are performed based on the detected intensity of each interference signal.

8. The detection and control subsystem according to any one of claims 1 to 3, wherein each OPL tuner corresponding to each optical channel comprises at least one optical path determination unit configured to guide an incident light beam through one optical path from a plurality of selectable optical paths of at least one optical path determination unit in the OPL tuner, and one or more of the latest tuner control properties relate to the latest selection of a particular optical path.

9. The detection and control subsystem according to claim 8, wherein each optical path determination unit of the OPL regulating device comprises a fiber manifold having a manifold of path determination optical fibers, and at least some of the path determination optical fibers are connected to one or more other path determination optical fibers of the fiber manifold by one or more controllable path determination switches, and the detection and control subsystem sets and selects a specific optical path which is a specific amount of additional OPL ΔOPL to the OPL of the optical beam propagating through the optical fiber corresponding to each channel.

10. The detection and control subsystem according to claim 9, wherein the fiber manifold is configured in a cascaded manner such that at least one of the controllable routing switches is operationally associated with at least two other controllable routing switches.

11. The detection and control subsystem according to claim 8, wherein each path determination unit of each OPL regulating unit comprises at least two reflectors configured to control the additional OPL amount ΔOPL by adjusting the position of at least one of its reflectors and / or adjusting the direction of the light beam incident on the path determination unit.

12. The detection and control subsystem according to claim 11, wherein at least one of the reflectors is operated by a controllable actuator comprising at least one motor and at least one movable element to controllably adjust the position of the reflector.

13. The at least one control unit is For each optical channel Determine an appropriate amount of additional OPL ΔOPL for the OPL of the light beam propagating through the corresponding optical fiber of the optical channel. Select the appropriate optical path determination state for each OPL tuner corresponding to the determined OPL addition amount ΔOPL. Control at least one optical path determination unit of the OPL tuner of the optical channel according to the selected optical path. The detection and control subsystem according to claim 8, configured as described above.

14. The detection and control subsystem according to any one of claims 1 to 3, wherein each OPL regulator is configured to control the temperature of at least one fiber portion of a corresponding optical fiber in the fiber array of the multi-channel optical system to adjust the length of the optical fiber in the corresponding optical array of the multi-channel optical system.

15. Each OPL controller is: The heat conduction elements of the OPL regulator are actively heated, allowing only natural, passive cooling of the heated optical fiber portion through natural heat dissipation, or The heat conduction elements of the OPL controller are to be actively heated and actively cooled. The detection and control subsystem according to claim 14, configured to perform one of the following:

16. The detection and control subsystem according to claim 14, wherein each OPL tuner comprises at least one thermal conductive element coupled to a corresponding fiber portion of the optical fiber of the multi-channel optical system, the thermal conductive element being at least controllably heated to extend the length of the corresponding optical fiber and, consequently, the OPL of the corresponding light beam passing through the optical fiber.

17. Each heat conduction element is A wire or strap wrapped around the outer surface of each fiber section, A raised heat conductive element around which the aforementioned optical fiber is wound The detection and control subsystem according to claim 16, comprising:

18. Each heat-conducting element is raised, By using one or more mounting or coupling means, By winding the corresponding optical fiber around the raised heat conductive element, The detection and control subsystem according to claim 14, which is coupled to the corresponding optical fiber.

19. The detection and control subsystem according to claim 14, wherein each controllable temperature controller comprises a thermoelectric cooler for actively heating and cooling the at least one fiber section.

20. The detection and control subsystem according to claim 14, wherein the OPL adjustment subsystem further comprises a sensor array having a plurality of temperature sensors, each installed and configured to measure the temperature near the temperature control area of ​​the corresponding optical fiber of the corresponding optical channel, and each OPL adjustment is performed based on the measured current temperature of the corresponding temperature control area of ​​the corresponding optical fiber.

21. The detection and control subsystem according to claim 14, wherein the OPL regulator comprises at least one illuminator configured to irradiate the corresponding fiber portion of the corresponding optical fiber of each optical channel associated with itself by irradiating the fiber portion.

22. The at least one illuminator is installed outside its corresponding fiber section, The detection and control subsystem according to claim 21, wherein each illuminator is configured to emit light of one or more wavelengths or wavelength bands corresponding to the spectral absorption characteristics of at least a portion of the irradiated fiber.

23. The detection and control subsystem according to claim 21, wherein the at least one illuminator is configured and installed such that the light emitted therefrom propagates at an angle to the propagation direction of the light beam propagating through the corresponding fiber portion, and a non-zero angle is formed between the propagation direction of the light beam and the propagation direction of the light emitted from the at least one illuminator.

24. The detection and control subsystem according to claim 14, wherein each OPL regulator comprises an illuminator having one or more light sources and an additional fiber section connected to the optical fiber of each optical channel of the multi-channel optical system, the illuminator is installed and configured to extend the total length of the additional fiber section to regulate the OPL of the light beam propagating through each optical fiber and the additional fiber section by irradiating at least a portion of it to heat the additional fiber section.

25. The detection and control subsystem according to claim 24, wherein the additional fiber portion is a doped optical fiber having at least one dopant having known light absorption properties, and the illuminator of the OPL tuner is configured to emit light corresponding to the light absorption properties of the additional fiber portion.

26. The detection and control subsystem according to claim 25, wherein the illuminator of the OPL regulator is connected to the additional fiber section and irradiates the cladding section of the additional fiber section.

27. The detection and control subsystem according to claim 25, wherein the additional fiber portion is doped with thulium (Tm) dopant.

28. The detection and control subsystem according to claim 25, wherein each optical fiber of the multi-channel optical system has different light absorption characteristics from each additional fiber section.

29. The detection and control subsystem according to claim 21, wherein the at least one illuminator is configured such that one or more of its illumination characteristics are controllable.

30. The aforementioned one or more lighting characteristics are The wavelength and / or wavelength bandwidth of the illumination, Illumination intensity, power, amplitude, spatial distribution and / or flux, Radiation opening, Direction of radiation propagation, Duration of irradiation, and / or One or more irradiation pulse characteristics The detection and control subsystem according to claim 29, comprising one or more of the above.

31. A method for adjusting the optical path length (OPL) of a multi-channel optical system and defining the corresponding array of optical channels using multiple optical fiber arrays for guiding multiple light beams passing through them, The OPL adjustment subsystem is provided, comprising at least one array of OPL tuners, each configured to adjust the OPL of at least one light beam of the multi-channel optical system. A control unit is provided that is configured to process the received data and control at least each OPL regulator, For each optical channel, The detection unit detects one or more of the latest optical characteristics related to the light beam of each optical channel output from the multi-channel optical system. Analyzing the received characteristics of the light beam in each optical channel, and determining, using the control unit, one or more state-of-the-art tuner control properties, each related to the necessary state-of-the-art OPL adjustment for the light beam propagating through each optical channel, This includes, at least, adjusting the OPL of each light beam using the control unit by controlling each OPL tuner according to the determined one or more state-of-the-art tuner control properties, The detection, analysis, and OPL adjustment are performed in parallel for all optical channels of the multi-channel optical system. method.

32. The method according to claim 31, wherein the multi-channel optical system is coherent beam coupling (CBC), and the OPL adjustment is performed to reduce the optical path difference (OPD) between the light beams of the CBC system.

33. (i) Using the irradiation unit of the multi-channel optical system, generate an array of input light beams having similar optical properties, (ii) Using the CBC unit of the multi-channel optical system, the arrays of input light beams are coupled to form corresponding arrays of output light beams that propagate parallel to each other and define optical axes parallel to their own propagation direction, (iii) Using a waveguide unit comprising at least one fiber array having multiple optical fibers, the array of the input optical beam is guided to the CBC unit. The method according to claim 32, further comprising:

34. Generating or sampling and guiding a reference light beam, The array of output light beams is guided such that a first portion of each light beam is guided along the optical axis, and a second portion of each light beam is guided in a propagation direction different from the propagation direction of the optical axis, interfering with the corresponding portion of the reference light beam, generating a corresponding interference signal, thereby forming an array of interference signals. It is configured to separately detect at least the intensity of each interference signal and output the corresponding latest intensity-related data. The control unit, in order to achieve the relevant OPL tuning of the light beam, receives and analyzes the latest intensity-related data of each interference signal of each optical channel in parallel, determines the necessary one or more latest tuner control properties, and controls each OPL tuner in parallel according to the determined latest tuner control properties. The method according to any one of claims 31 to 33, further comprising:

35. The latest intensity-related data corresponding to each interference signal is: - The total intensity of the corresponding interference signal, - The main peak of the beam profile of the corresponding interference signal, - The overall intensity of the main lobe of the beam profile of the corresponding interference signal, The method according to claim 34, wherein one or more of the above are shown.

36. The latest intensity-related data received for each interference signal is used to determine its value. Default baseline value, or One or more of the previously measured, sequentially measured intensity-related values ​​of the interference signal of the same corresponding optical channel. The method according to claim 34, which is analyzed by comparison with the method described above.

37. Using a phase-fixing unit equipped with an array of phase adjusters, the phase of each input light beam of each optical channel is adjusted, Using a polarization-fixing unit comprising at least one array of polarizers, the polarization of each input light beam in each optical channel is adjusted, Controlling the beam steering of the output light beam by controlling the relative phase between the input light beam and the output light beam. The method according to claim 34, further comprising at least one of the, wherein the fixing of the phase and / or polarization and / or the beam steering are performed based on the detected intensity of each interference signal.

38. The method according to any one of claims 31 to 33, wherein the OPL tuning of each optical channel is performed by guiding an incident light beam to pass through one of a plurality of selectable optical paths made available by the OPL tuner, and the one or more latest tuner control properties relate to the latest selection of a particular optical path.

39. The method according to claim 38, wherein the path determination of the optical beam is performed using an OPL tuner comprising a fiber manifold comprising a path determination optical fiber manifold, at least some of the path determination optical fibers are connected to one or more other path determination optical fibers of the fiber manifold by one or more controllable path determination switches, and a specific optical path which is a specific OPL addition amount ΔOPL to the OPL of the optical beam propagating through the optical fiber corresponding to each channel is set and selected.

40. The method according to claim 38, wherein the path determination of the light beam is performed by an OPL regulator comprising at least one path determination unit, and each path determination unit comprises at least two reflectors configured to control the additional OPL amount ΔOPL by adjusting the position of at least one of itself and / or adjusting the direction of the light beam as it is incident on the path determination unit.

41. For each optical channel, Determining an appropriate amount of additional OPL ΔOPL for the OPL of the optical beam propagating through the corresponding optical fiber of each optical channel, Select the appropriate optical path determination state for each OPL tuner corresponding to the determined OPL addition amount ΔOPL, Controlling at least one corresponding optical path determination unit of each OPL tuner according to the selected optical path. The method according to claim 38, further comprising:

42. The method according to any one of claims 31 to 33, wherein the OPL adjustment is performed by controlling the temperature of at least one fiber portion of the corresponding optical fiber in the fiber array of the multichannel optical system to adjust the length of the optical fiber in the corresponding fiber array of the multichannel optical system, and each OPL adjuster is configured to heat at least one or more fiber portions of the corresponding optical fiber in the multichannel optical system.

43. Each OPL controller is: The heat conduction elements of the OPL regulator are actively heated, allowing only natural, passive cooling of the heated optical fiber portion through natural heat dissipation, or The heat conduction elements of the OPL controller are to be actively heated and actively cooled. The method according to claim 42, configured to perform one of the following.

44. The method according to claim 42, wherein each OPL tuner comprises an illuminator having one or more light sources and an additional fiber section connected to the optical fiber of each optical channel of the multi-channel optical system, the OPL tuning is performed by irradiating at least a portion of the additional fiber section to heat it, thereby extending the total length of the additional fiber section to tun the OPL of the light beam propagating through each optical fiber and the additional fiber section.

45. One or more illumination characteristics of the illuminator of the OPL controller are controllable, and the one or more illumination characteristics are Wavelength and / or wavelength bandwidth of illumination, Illumination intensity, power, amplitude, spatial distribution and / or flux, Radiation opening, Direction of radiation propagation, During the irradiation period, One or more pulse characteristics and The method according to claim 44, comprising one or more of the above.

46. The method according to claim 44, wherein the additional fiber portion is a doped optical fiber having at least one dopant having known light absorption properties, and the illuminator of the OPL tuner is configured to emit light corresponding to the light absorption properties of the additional fiber portion.

47. The method according to claim 44, wherein the illuminator of the OPL regulator is connected to the additional fiber section and irradiates the cladding section of the additional fiber section.

48. The method according to claim 43, wherein the temperature control is performed by irradiating the fiber portion of each optical fiber in the multi-channel optical system, and the OPL regulator comprises at least one illuminator configured to heat the corresponding fiber portion of the corresponding optical fiber of each optical channel associated with itself by irradiating the fiber portion.

49. The method according to claim 48, wherein the at least one illuminator is configured and installed such that the light emitted therefrom propagates at an angle to the propagation direction of the light beam propagating through the corresponding fiber portion, and a non-zero angle is formed between the propagation direction of the light beam and the propagation direction of the light emitted from the at least one illuminator.

50. The method according to claim 48, wherein the at least one illuminator is configured such that one or more of its lighting characteristics are controllable.

51. The aforementioned one or more lighting characteristics are: The wavelength and / or wavelength bandwidth of the illumination, Illumination intensity, power, amplitude, spatial distribution and / or flux, Radiation opening, The direction of radiation propagation, and / or During the irradiation period, One or more irradiation pulse characteristics The method according to claim 50, comprising one or more of the above.

52. The method further includes measuring the temperature near the temperature control area of ​​each optical fiber using a sensor array comprising multiple temperature sensors, wherein each temperature sensor is installed and configured to sense the temperature of the fiber portion of a specific optical channel optical fiber in the temperature control area where the OPL controller is installed. The method according to claim 42, wherein the necessary temperature adjustment for each OPL adjustment is performed based on the measured current temperature of the corresponding temperature-controlled area of ​​the corresponding optical fiber.

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