WO2025059271A1

WO2025059271A1 - Sensing and imaging system

Info

Publication number: WO2025059271A1
Application number: PCT/US2024/046340
Authority: WO
Inventors: David J. Digiovanni; Tristan KREMP; Erin S. LAMB; Zhou SHI; Paul S. Westbrook
Original assignee: OFS Fitel LLC
Current assignee: OFS Fitel LLC
Priority date: 2023-09-13
Filing date: 2024-09-12
Publication date: 2025-03-20
Anticipated expiration: 2026-03-13

Abstract

Optical fiber systems for permitting both shape sensing and imaging include an optical fiber and a fan-in device (such as a tapered fiber combiner (TFC) or a tapered fiber bundle (TFB)). The optical fiber comprises a sensing core that is inscribed with fiber Bragg gratings (FBGs). The sensing core is surrounded by an imaging waveguide. The imaging waveguide is surrounded by a fiber cladding. The TFC comprises a tapered sensing core that is optically coupled to the sensing core of the optical fiber. The tapered imaging core is optically coupled to the imaging waveguide of the optical fiber. The TFC further comprises a tapered inner cladding that surrounds both the tapered sensing core and the tapered imaging core. The tapered inner cladding is also optically coupled to the imaging waveguide. An outer cladding surrounds the tapered inner cladding and is optically coupled to the fiber cladding.

Description

SENSING AND IMAGING SYSTEM

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. provisional patent application serial number 63/538,189, filed on 2023-September-13, listing as first-named inventor David J. DiGiovanni, and having the title "Shape Sensing and Imaging Fan-in or Fan-out, Fiber, and System," which is incorporated herein by reference in its entirety.

BACKGROUND

FIELD OF THE DISCLOSURE

[0002] The present disclosure relates generally to optics and, more particularly, to optical fibers.

DESCRIPTION OF RELATED ART

[0003] There are many applications for optical fibers. However, different parameters or optical characteristics may be desirable for different applications. Consequently, it is entirely possible that parameters that are suitable for one application are unsuitable for other applications.

SUMMARY

[0004] The present disclosure provides systems and methods that are capable of concurrent sensing and imaging. One embodiment of the system comprises an optical fiber and a fan-in device (such as a tapered fiber combiner (TFC) or a tapered fiber bundle (TFB)). The optical fiber comprises sensing cores that may be inscribed with fiber Bragg gratings (FBGs). The sensing cores are surrounded by an imaging waveguide. The imaging waveguide is surrounded by a fiber cladding. The TFC comprises tapered sensing cores that are optically coupled to the sensing cores of the optical fiber. The TFC also comprises a tapered imaging core that is optically coupled to the imaging waveguide of the optical fiber. The TFC further comprises a tapered inner cladding that surrounds both the tapered sensing cores and the tapered imaging core. The tapered inner cladding is also optically coupled to the imaging waveguide. An outer cladding surrounds the tapered inner cladding and is optically coupled to the fiber cladding.

[0005] Other systems, devices, methods, features, and advantages will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure.

Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0007] FIG. 1 is a diagram showing an experimental setup in one embodiment of an optical-fiber-based combined sensing and imaging system.

[0008] FIG. 2 is a diagram showing an enlarged side view of one embodiment of a fan-in/fan-out portion (also designated as a tapered fiber combiner (TFC) portion or a tapered fiber bundle (TFB) portion) of the system of FIG. 1.

[0009] FIG. 3 is a diagram showing an embodiment of the TFC of FIG. 2.

[0010] FIG. 4 is a diagram showing an embodiment of a combined sensing and imaging optical fiber.

[0011] FIG. 5 is a diagram showing light intensity in an axial view of the optical fiber of FIG. 4 at line B-B for light introduced at an imaging core.

[0012] FIG. 6 is a diagram showing light intensity in an axial view of the optical fiber of FIG. 4 at line C-C for light introduced at the imaging core.

[0013] FIG. 7 is a diagram showing light intensity in an axial view of the optical fiber of FIG. 4 at line C-C for light introduced at a sensing core.

[0014] FIG. 8 is a diagram showing an enlarged side view of another embodiment of the TFC portion of the system of FIG. 1.

[0015] FIG. 9 is a diagram showing an enlarged axial view of the embodiment shown in FIG. 8. [0016] FIG. 10 is a diagram showing an enlarged side view of yet another embodiment of the TFC portion of the system of FIG. 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] For some environments, such as, for example, surgical environments, it is desirable to perform both sensing and imaging functions using the same device. Using a single device for multiple functions is oftentimes simpler than using multiple, separate devices. Currently, there are fiber-optic sensors that use fiber Bragg gratings, Rayleigh scattering, Raman scattering or Brillouin scattering to permit measurement of shape, temperature, pressure, and other environmental variations along the length of the fiber. There are also imaging optical fibers that permit imaging and optical power delivery fibers that permit delivery of high optical power to a target at the distal end of the fiber. However, combining the sensing function with the imaging function in a single optical fiber poses many difficulties. For example, imaging typically requires high brightness and a larger light collection area because image resolution depends on the number of guided modes that are excited in the optical fiber and out-coupled to a detector. Optical power delivery requires similar optical properties, particularly if a particular shape of the beam at the distal fiber exit is desired. Additionally, the presence of an imaging core in an optical fiber makes it difficult (if not impossible) to inscribe the sensing cores with FBGs if the imaging core is opaque to actinic radiation (e.g., ultraviolet (UV) radiation, high-intensity (ultrashort, e.g., femtosecond) pulses, etc.).

[0018] This disclosure teaches optical-fiber-based systems with both sensing and imaging capabilities. Unlike conventional silica-based imaging fibers in which imaging signals are transmitted through one or more cores that are surrounded by a glass cladding, with the only function of the glass cladding being to contain the signals to the cores, the disclosed system uses that glass cladding as an imaging waveguide. In other words, the disclosed system comprises sensing cores (which may be inscribed with FBGs), which are surrounded by an imaging waveguide, which in turn is surrounded by an outer cladding. This permits both sensing applications (via the sensing cores) and imaging or optical power delivery applications (via the imaging waveguide) with a single optical fiber. The imaging waveguide is substantially transparent to actinic radiation, while the sensing cores are photosensitive to actinic radiation. Thus, FBGs can be inscribed in the sensing cores using actinic radiation without that same actinic radiation substantially affecting the imaging waveguide. By providing both sensing and imaging capabilities, the disclosed system also permits near-real-time measurement of changes in a transmission matrix (TM) using the sensing abilities, which further permits near-real-time calibration of the system for imaging or power delivery.

[0019] Having provided a broad technical solution to a technical problem, reference is now made in detail to the description of the embodiments as illustrated in the drawings. While several embodiments are described in connection with these drawings, there is no intent to limit the disclosure to the embodiment or embodiments disclosed herein. On the contrary, the intent is to cover all alternatives, modifications, and equivalents.

[0020] FIG. 1 is a diagram showing an experimental setup in one embodiment of an optical-fiber-based combined sensing and imaging system 100. As shown in FIG. 1, the system 100 comprises an imaging portion that starts at a laser 102, which provides the light beam for imaging. Insofar as this laser 102 is a conventional laser used for imaging (e.g., providing a 532 nanometer (nm) imaging light) that is well known in the art, only a truncated description of the laser 102 is provided herein. The laser 102 is optically coupled to a first beam splitter (BS) 104, which splits the imaging beam into two (2) separate paths, designated herein as a first path 106 and a second path 108. The first path 106 optically couples the BS 104 to a spatial light modulator (SLM) 112 that allows for the calibration of a multimode waveguide for imaging using a series of linearly independent (preferably orthogonal) patterns. The second path 108 optically couples the BS 104 to a reference single-mode fiber (SMF) 110 that is used for a reference beam that is split from the same laser 102 as the imaging beam (in the first path 106). The SLM 112 is optically coupled to a first microscope objective (MO) 114 that conveys the imaging beam to an imaging lead fiber 116 (also designated herein as an imaging input 116), which is optically coupled to a fan-in device 118, shown herein as a tapered fiber combiner (TFC) 118 or a tapered fiber bundle (TFB) 118. Insofar as conventional devices can be used for both the SLM 112 and the MO 114, only a truncated discussion of the SLM 112 and the MO 114 is provided herein.

[0021] The system 100 also comprises a sensing portion that ends at an optical backscattering reflectometer (OBR) 120 that is optically coupled to a splitter 122 that provides multiple sensing inputs 124 to the TFC 118. In the embodiment of FIG. 1, the splitter 122 is a 1x4 splitter that provides four (4) sensing inputs 124 to the TFC 118. Again, to the extent that a conventional OBR 120 and a conventional splitter 122 can be used in the system 100, only a truncated discussion of the OBR 120 and the splitter 122 is provided herein. We note that the term "input" here is meant geometrically with respect to the orientation of the taper rather than with respect to the direction of the sensing light. For some embodiments, sensing data are collected using the sensing inputs 124 (or sensing leads) and sent to the OBR 120 through the splitter 122 so that the signal from all sensing inputs 124 can be collected substantially simultaneously. Likewise, imaging data is collected using the imaging input fiber 116 and sent to an imaging camera (not shown).

[0022] Continuing, a distal end of the TFC 118 is optically coupled to a proximal end of an optical fiber 126. Insofar as both sensing inputs 124 and an imaging input 116 are provided at a proximal end of the TFC 118, the light at the distal end of the TFC 118 includes both backward-propagating sensing data and, also, imaging data. The optical fiber 126 receives the imaging data and provides the backpropagating sensing data. For convenience, the optical fiber 126 is also designated herein as a sensing-imaging fiber 126 (insofar as the optical fiber 126 carries both imaging data and sensing data). For purposes of calibration, a distal end of the optical fiber 126 is optically coupled to a second MO 128, which in turn is optically coupled to a second BS 130. The second BS 130 is also optically coupled to the reference SMF 110, thereby permitting the system 100 to combine the optical signal from the second MO 128 with the reference optical signal from the reference SMF 110. The second BS 130 is optically coupled to a detection device, such as a camera 132.

[0023] Of particular interest is the combination of the imaging input 116, the sensing inputs 124, the TFC 118, and the sensing-imaging fiber 126, which is shown as a fan-in/fan- out portion in box 200 and described in greater detail with reference to FIGS. 2 through 10. The fan-in/fan-out portion 200 is also designated herein as a TFC portion 200 or a TFB portion 200, as a preferred embodiment of the fan-in/fan-out device 118 is shown as a TFC 118.

[0024] FIG. 2 is a diagram showing an enlarged side view 200 of one embodiment of the TFC portion 200 of FIG. 1. As shown in FIG. 2, the TFC portion 200 comprises the imaging input 116, the sensing inputs 124, the TFC 118, and the sensing-imaging fiber 126. The TFC 118 exhibits a taper, which has a larger cross-sectional area at its proximal end (toward the imaging input 116 and the sensing inputs 124) and a smaller cross-sectional area at its distal end (toward the sensing-imaging fiber 126). For some embodiments, the TFC 118 has a taper ratio (or a taper diameter ratio) of approximately 3 (meaning, the diameter reduces by a factor of 3 from the proximal end of the TFC 118 to the distal end of the TFC 118).

[0025] In some embodiments, fan-in device 118 may comprise free-space optical coupling rather than tapered fibers as shown in Fig 2. In this instance, conventional miniature bulk-optical systems containing elements such as lenses, prisms, and filters can be used to multiplex the light from the imaging input fibers 116 and sensing input fibers 124 onto sensing-imaging fiber 126. Such technology developed for spatial multiplexing of signals from space division multiplexing in optical fiber systems is beneficial for coupling to sensing-imaging fiber, with a significant difference that in the present instance, fan-in device 118 must provide bi -direction coupling of light into both singlemode and multimode regions. [0026] In some embodiments, particularly those related to tapered fibers, the sensing inputs 124 are double-clad pedestal fibers that have a mode-field diameter (MFD) that is similar to a standard single-mode fiber at an operating wavelength (A.) of approximately 1550 nanometers (~1550nm). The imaging input 116, in some embodiments, is a multimode (MM) fiber with a 110 micrometer (110pm) core diameter.

[0027] In the embodiment of FIG. 2, the sensing-imaging fiber 126 comprises an imaging core 216 and multiple sensing cores 224, all of which are surrounded by a lower- index inner cladding 220 (also designated herein as an imaging waveguide 220, as explained below). In other words, the refractive index (or, simply, index) of the inner cladding 220 is lower than the index of the sensing cores 224, thereby confining light that is launched into the sensing cores 224 to the sensing cores 224. The inner cladding 220 is surrounded by an even lower-index outer cladding 210a, 210b (collectively, 210), meaning, the index of the outer cladding 210 is lower than the index of the inner cladding 220. Thus, light in the inner cladding 220 is confined to the inner cladding 220 as a result of this index difference.

[0028] For some embodiments, the index of the imaging core 216 is substantially the same as the index of the inner cladding 220 and, thus, any imaging light that is launched into the sensing-imaging fiber 126 through the imaging core 216 spreads out to the entire inner cladding 220. Insofar as the outer cladding 210 confines the imaging light to the inner cladding 220, the inner cladding 220 acts as an imaging waveguide 220. Thus, a single optical fiber 126 is capable of carrying both sensing signals (through the sensing cores 224) and an imaging (or power-delivery) signal (through the imaging waveguide 220). It should be appreciated that, although the embodiment of FIG. 2 shows an outer cladding 210 surrounding only the optical fiber 126, other embodiments can have the outer cladding 210 surrounding both the optical fiber 126 and the TFC 118, thereby confining imaging light in both the TFC 118 and the optical fiber 126.

[0029] To more clearly illustrate the TFC portion 200, FIG. 3 is a diagram 300 that shows a perspective view of the TFC 118 of FIG. 2 in greater detail, while FIG. 4 is a diagram 400 that shows a perspective view of the sensing-imaging fiber 126 of FIG. 2 in greater detail. FIG. 4 further shows a coreless fiber 428 that is flat-cleaved to the sensingimaging fiber 126 (FIG. 1; not shown in FIG. 4) at its distal end, thereby enabling a cleaner field of view for imaging and reducing back reflections at the distal end of the sensingimaging fiber 126. Additionally, FIG. 4 shows the sensing fiber cores 224 as having inscribed gratings (e.g., fiber Bragg gratings (FBGs)), thereby improving the signal-to-noise ratio (SNR) when using the sensing fiber cores 224 to detect changes in, for example, shape, temperature, pressure, etc. The TFC 118 in FIG. 3 comprises tapered sensing cores 324 that are optically coupled to sensing inputs 124. Furthermore, the TFC 118 comprises a tapered imaging core 316, which is optically coupled to the imaging input 116. The tapered sensing cores 324 and the tapered imaging core 316 are surrounded by a tapered inner cladding 320. The distal end of the TFC 118 is shown with broken line A-A in FIG. 3. The proximal end of the optical fiber 126 is shown with broken line B-B in FIG. 4, while the distal end of the optical fiber 126 is shown with broken line C-C in FIG. 4. Thus, in architecture, A-A (in FIG. 3) is optically coupled to B-B (in FIG. 4) to form the TFC portion 200 that is shown in FIG. 2.

[0030] Consequently, in operation, when imaging light is launched into the imaging input 116, the imaging light propagates through the tapered imaging core 316 in FIG. 3. If the index of the tapered imaging core 316 is substantially similar to the index of the tapered inner cladding 320, then the imaging light that enters the tapered imaging core 316 will spread beyond the imaging core 316. Thus, as shown in the axial cross section 500 of FIG. 5, imaging light 540 at B-B in FIG. 4 will extend to a larger cross-sectional region beyond the imaging core 510 and into part of the inner cladding 530 (or imaging waveguide 530) in FIG. 5. When the imaging light has propagated through the optical fiber 126 (FIGS. 1 and 2) and reached the distal end of the optical fiber (line C-C in FIG. 4), the imaging light 640 (FIG. 6) has spread uniformly through the entire axial cross-section 600 (FIG. 6) of the optical fiber 126. Preferably, light in the sensing cores 520 (FIG. 5), 630 (FIG. 6) is largely unaffected by the imaging light, e.g., by using a different wavelength for the sensing light than for the imaging light. For embodiments that have an imaging core 216 in the optical fiber 126, the imaging core can exhibit a higher intensity 620 (FIG. 6) if there is a slight index mismatch between the imaging core 216 and the imaging waveguide 220.

[0031] However, unlike the imaging light, when sensing light is launched into the sensing inputs 124, the sensing light propagates through the sensing inputs 124, then through the tapered sensing cores 324 (FIG. 3) in the TFC 118, and then through the sensing fiber cores 224 (FIGS. 2 and 4) in the optical fiber 126. Thus, as shown in the cross-sectional view 700 of FIG. 7, sensing light that is launched in a sensing core 224 of the optical fiber 126 will remain confined in the sensing core 224 (as shown by the intensity in the sensing core 710 being higher than the intensity in the remaining imaging waveguide portion 740 (FIG. 7) of the optical fiber 126 (FIGS. 1 and 2).

[0032] Although FIG. 2 demonstrates an embodiment with an imaging core 216, it should be appreciated that other embodiments include systems 800 (FIG. 8), 900 (FIG. 9) with multiple imaging inputs 816 and multiple sensing inputs 824, which are propagated through a TFC and into a multicore optical fiber 826, which comprises multiple sensing cores 816 and multiple imaging cores 824 all ultimately surrounded by an outer cladding 810a, 810b (collectively, 810), such as the embodiment shown in FIGS. 8 and 9.

[0033] Insofar as the inner cladding 220 is the imaging waveguide 220, other embodiments, such as the system 1000 shown in FIG. 10, optically couple the tapered imaging cores directly to the imaging waveguide 1016 (confined by the cladding 1010a, 1010b (collectively, 1010)) and, thus, dispense altogether with the imaging cores in the optical fiber 1026. For these embodiments 1000, the imaging waveguide 1016 is a stepindex multimode (MM) imaging waveguide 1016, which surrounds multiple sensing singlemode (SM) cores 1024. Also, for actinic radiation to inscribe the sensing SM cores 1024 with FBGs, the sensing SM cores 1024 are photosensitive to the actinic radiation, while the MM imaging waveguide 1016 is substantially transparent to that same actinic radiation. Thus, the sensing SM cores 1024 are inscribable with FBGs without adversely affecting the MM imaging waveguide 1016.

[0034] Additionally, because the inner cladding operates as the MM imaging waveguide 1016, the MM imaging waveguide 1016 has a relatively large outer diameter of approximately 125 micrometers (~125pm). Furthermore, using known methods of manipulating refractive indices, the step-index MM imaging waveguide 1016 can be constructed to have a numerical aperture (NA) of approximately 0.45 at an operating wavelength ( ) of ~532nm, thereby providing a capacity of approximately 55,000 guided modes at of ~532nm. Ultimately, the imaging waveguide 1016 that is formed by the inner cladding glass and the low-index outer cladding (or coating) is similar to hard-clad silica (HCS) fibers (sometimes used in power delivery systems in that both imaging and power delivery fibers benefit from having high brightness and a large light collection area.

[0035] Providing concurrent sensing and imaging capabilities with a single optical fiber 126 can allow for near-real-time calibration of an optical-fiber-based imaging system. This is because the sensing fibers provide information that can be used to update a transmission matrix (TM) of the optical system that has been determined using known methods, such as phase-shifting interferometry with a reference beam in an environment similar to that shown in FIG. 1. The SLM 112 scans a spot over the input facet 116 of the system and measures the electric field of each resulting speckle pattern with the camera 132 in order to reconstruct the TM of the system. More precisely, the TM between the proximal end and the distal end of the optical fiber 126 is measurable in near-real-time based on known computing processes. For example, phase drift is tracked in near-real-time during the TM measurement and compensated using a fitting algorithm, such as Levenberg-Marquardt minimization routines that are known in the art. Once the TM (which is now measurable in near-real-time) is determined, the TM correspondingly permits near-real-time calibration of optical properties of the system. This can be utilized to reconstruct an image collected from the distal end of fiber 126, or to shape the light beam exiting the distal end of fiber 126 to, for example, focus the beam to a spot on a target, for power delivery applications. It should be appreciated that the phrase "near-real-time" means the substantially concurrent occurrence with only slight delays associated with processing speeds or latency for data transmission. [0036] Thus, if sensing-imaging fibers (such as those shown herein) are used for minimally invasive robotic surgery, then the images that are collected from the imaging waveguides can be calibrated in near-real-time for more accurate navigation or image reconstruction. By integrating sensing functionality and imaging functionality in the same optical fiber, the disclosed systems and processes allow for sensing (e.g., shape, bend, temperature, pressure, etc.), visualization (e.g., imaging), and optical power delivery in a single, compact device, which can be regularly (and almost continuously) calibrated in near- real-time, even possibly during the medical procedure itself.

[0037] Any process descriptions or blocks in flow charts should be understood as representing specific functions or steps in the process, and alternative implementations are included within the scope of the preferred embodiment of the present disclosure in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present disclosure.

[0038] Although exemplary embodiments have been shown and described, it will be clear to those of ordinary skill in the art that a number of changes, modifications, or alterations to the disclosure as described may be made. For example, although a lower-index outer cladding is shown with reference to the disclosed embodiments, other embodiments of sensing-imaging fibers can have graded-index (GRIN) imaging cores and a high-index outer cladding, thereby allowing for imaging with the GRIN imaging cores (rather than imaging with the inner cladding). Also, higher brightness that is desirable for imaging applications can be achieved by increasing core diameter (of the imaging waveguide), numerical aperture, or both. Furthermore, while preferred embodiments teach fan-in or fan-out devices, such as TFCs or TFBs, to couple the imaging light into the imaging waveguide, it should be appreciated that the imaging light may also be coupled into the imaging waveguide by free- space coupling. Moreover, the TFB or TFC can either use separate input ports for power delivery and imaging or, in the alternative, use a single input port that accommodates both power delivery and imaging. Next, although various aspects of this disclosure teach the principles of operation in a calibration system (such as that shown in FIG. 1), it should be appreciated that the system of FIG. 1 can readily be converted to an imaging or power- delivery system by configuring the system with a detector that receives back-propagating imaging signals. In some embodiments, an endcap is added at the distal end of the sensing and imaging fiber, rather than (or in addition to) a flat-cleaved coreless fiber. It should be appreciated that a shorter endcap with an angle cleave can be used to minimize back reflections. All such changes, modifications, and alterations should therefore be seen as within the scope of the disclosure.

Claims

What is claimed is:

1. A system comprising: a multicore optical fiber comprising: an optical fiber proximal end; an optical fiber distal end; sensing single-mode (SM) cores, each sensing SM core being photosensitive to actinic radiation; fiber Bragg gratings inscribed on each sensing SM core; a step-index multimode (MM) imaging waveguide surrounding the sensing SM cores, the step-index MM imaging waveguide being substantially transparent to the actinic radiation, the step-index MM imaging waveguide having: an outer diameter of approximately 125 micrometers (~125pm); a numerical aperture (NA) of approximately 0.45 at an operating wavelength ( ) of approximately 532 nanometers (~532nm); and a capacity of approximately 55,000 guided modes at X of ~532nm; a fiber cladding surrounding the step-index MM imaging waveguide; and a tapered fiber combiner (TFC) optically coupled to the optical fiber proximal end, the TFC comprising: tapered sensing cores, each tapered sensing core being optically coupled to a corresponding sensing SM core; a tapered imaging core optically coupled to the step-index MM imaging waveguide; and a tapered inner cladding surrounding the tapered sensing cores, the tapered inner cladding further surrounding the tapered imaging core, the tapered inner cladding being optically coupled to the step-index MM imaging waveguide; and an outer cladding optically coupled to the fiber cladding.

2. The system of claim 1, farther comprising: a coreless fiber flat-cleaved to the optical fiber distal end.

3. A system comprising: a multicore optical fiber comprising: an optical fiber proximal end; an optical fiber distal end; sensing single-mode (SM) cores; a multimode (MM) imaging waveguide surrounding the sensing SM cores; and a fiber cladding surrounding the MM imaging waveguide; and a fan-in combiner optically coupled to the optical fiber proximal end, the fan-in comprising: sensing fan-in cores, each sensing fan-in core being optically coupled to a corresponding sensing SM core; an imaging core optically coupled to the MM imaging waveguide; and an inner cladding surrounding the sensing fan-in cores, the inner cladding further surrounding the imaging core, the inner cladding being optically coupled to the MM imaging waveguide; and an outer cladding optically coupled to the fiber cladding.

4. The system of claim 3, further comprising: a coreless fiber optically coupled to the optical fiber distal end.

5. The system of claim 3, wherein the fan-in combiner comprises a fan-in distal end and a fan-in proximal end, the system further comprising: an imaging input optically coupled to the imaging core at the fan-in proximal end; and sensing inputs, each sensing input being optically coupled to a corresponding sensing fan-in core at the TFC proximal end.

6. The system of claim 5, further comprising: a splitter comprising: a splitter input; and splitter outputs, each splitter output being optically coupled to a corresponding sensing input; and an optical back-scattering reflectometer (OBR) optically coupled to the splitter input, the OBR for collecting shape-sensing data from the sensing SM cores via the sensing fan-in cores, the sensing inputs, and the splitter.

7. The system of claim 6, further comprising: an input facet of the MM imaging waveguide; and a spatial light modulator (SLM) optically coupled to the imaging input, the SLM for optically scanning the input facet of the MM imaging waveguide.

8. The system of claim 3, further comprising: a transmission matrix (TM) measurable in near-real-time between the optical fiber proximal end and the optical fiber distal end.

9. A system comprising: an optical fiber comprising: an optical fiber proximal end; an optical fiber distal end; a sensing fiber core; fiber Bragg gratings inscribed on the sensing core; an imaging waveguide surrounding the sensing core; and a fiber cladding surrounding the imaging waveguide; and a tapered fiber combiner (TFC) optically coupled to the optical fiber proximal end, the TFC comprising: a tapered sensing core optically coupled to the sensing fiber core; a tapered imaging core optically coupled to the imaging waveguide; and a tapered inner cladding surrounding the tapered sensing core, the tapered inner cladding further surrounding the tapered imaging core, the tapered inner cladding being optically coupled to the imaging waveguide; and an outer cladding optically coupled to the fiber cladding.

10. The system of claim 9, further comprising a coreless fiber optically coupled to optical fiber distal end.

11. The system of claim 9, wherein the sensing fiber core is a sensing single-mode (SM) core.

12. The system of claim 9, wherein the imaging waveguide is a multimode (MM) imaging waveguide.

13. The system of claim 9, wherein the fan-in combiner is a tapered fiber combiner (TFC), the TFC comprising a TFC distal end and a TFC proximal end, the system further comprising: an imaging input optically coupled to the tapered imaging core at the TFC proximal end; and a sensing input optically coupled to the tapered sensing core at the TFC proximal end.

14. The system of claim 13, further comprising an optical back-scattering reflectometer (OBR) optically coupled to the sensing input.

15. The system of claim 13, further comprising a spatial light modulator (SLM) optically coupled to the imaging input.

16. The system of claim 9, wherein the imaging waveguide is a step-index multimode (MM) imaging waveguide.

17. The system of claim 9, wherein the imaging waveguide comprises: a numerical aperture (NA) of approximately 0.45 at an operating wavelength (X) of approximately 532 nanometers (~532nm); and a capacity of approximately 55,000 guided modes at X of ~532nm.

18. The system of claim 9, further comprising: a transmission matrix (TM) measurable between the optical fiber proximal end and the optical fiber distal end.

19. The system of claim 18, wherein the TM is measurable in near-real-time.

20. The system of claim 19, wherein the TM permits near-real-time calibration of optical properties of the system.