Patent Description:
Fiber optic catheters and endoscopes have been developed to access to internal organs. For example in cardiology, OCT (optical coherence tomography) has been developed to see depth resolved images of vessels with a catheter. The catheter, which may include a sheath, a coil and an optical probe, may be navigated to a coronary artery.

Optical coherence tomography (OCT) is a technique for obtaining high resolution cross-sectional images of tissues or materials, and enables real time visualization. The aim of the OCT techniques is to measure the time delay of light by using an interference optical system or interferometry, such as via Fourier Transform or Michelson interferometers. A light from a light source delivers and splits into a reference arm and a sample (or measurement) arm with a splitter (e.g., a beamsplitter). A reference beam is reflected from a reference mirror (partially reflecting or other reflecting element) in the reference arm while a sample beam is reflected or scattered from a sample in the sample arm. Both beams combine (or are recombined) at the splitter and generate interference patterns. The output of the interferometer is detected with one or more detectors, such as, but not limited to, photodiodes or multi-array cameras, in one or more devices, such as, but not limited to, a spectrometer (e.g., a Fourier Transform infrared spectrometer). The interference patterns are generated when the path length of the sample arm matches that of the reference arm to within the coherence length of the light source. By evaluating the output beam, a spectrum of an input radiation may be derived as a function of frequency. The frequency of the interference patterns corresponds to the distance between the sample arm and the reference arm. The higher frequencies are, the more the path length differences are. Single mode fibers are commonly used for OCT optical probes, and double clad fibers are also commonly used for fluorescence and/or spectroscopy.

Spectrally encoded endoscope (SEE) is an endoscope technology which uses a broadband light source, a rotating or oscillating grating and a spectroscopic detector to encode spatial information from a sample. When illuminating light to the sample, the light is spectrally dispersed along one illumination line, such that the dispersed light illuminates a specific position of the illumination line with a specific wavelength. When the reflected light from the sample is detected with a spectrometer, the intensity distribution is analyzed as the reflectance along the line where the wavelength encodes the spatial information. By rotating or oscillating the grating to scan the illumination line, a two-dimensional image of the sample is obtained.

In order to acquire cross-sectional images of tubes and cavities such as vessels, and/or esophagus and nasal cavities, the optical probe is rotated with a fiber optic rotary joint (FORJ). A FORJ is the interface unit that operates to rotate one end of a fiber and/or an optical probe. In general, a free space beam coupler is assembled to separate a stationary fiber and a rotor fiber inside the FORJ. Besides, the optical probe may be simultaneously translated longitudinally during the rotation so that helical scanning pattern images are obtained. This translation is most commonly performed by pulling the tip of the probe back along a guidewire towards a proximal end and, therefore, referred to as a pullback.

A multi-modality system such as an OCT, fluorescence, and/or spectroscopy system with an optical probe is developed to obtain multiple information at the same time. The multimodality FORJ has a beam combiner for at least two beams with multiple wavelengths to couple into the probe. Generally, lenses are assembled to make collimated beams for both stationary and rotor fibers in the beam combiner. Further, the detected light may be collected in the same or in one or more additional fibers, and, if rotating, these additional fibers may structurally interfere with each other.

It is difficult to make collimated beams for the common rotor fibers with different wavelengths, especially when the wavelength differences are large (e.g., in the range of <NUM> to <NUM>, about double, etc.). An achromatic lens could be used to correct chromatic aberration; however, it is still difficult to control beam waist positions with multiple wavelengths to have high coupling efficiencies. Also, lenses with corrected aberrations are undesirably large, so a FORJ would become undesirably large (e.g., focal length and lens material(s) may increase size as well).

Accordingly, it would be desirable to provide at least one FORJ for use in at least one optical device, assembly or system to address one or more of the aforementioned inefficient and wasteful drawbacks, especially in a way that reduces or minimizes cost of manufacture, maintenance and/or use and/or in a way that achieves a compact FORJ with high coupling efficiency. Prior art can be found e.g. in document <CIT> disclosing a multimodal catheter system and method for intravascular analysis, document <CIT> disclosing a tissue imaging and image guidance in luminal anatomic structures and body cavities, and document <CIT> disclosing systems for optical imaging of biological tissues.

Accordingly, it is a broad object of the present disclosure to provide fiber optic rotary joints that may be used with one or more optical apparatuses, systems, methods (for using and/or manufacturing) and storage mediums, such as, but not limited to, fiber optic catheters, endoscopes and/or optical coherence tomography (OCT) apparatuses and systems, and methods and storage mediums, for use with same, to achieve structural compactness and high coupling efficiency. One or more additional objects of the present disclosure are to provide an easy way to fabricate a free space optical beam combiner and to provide an easy way to manufacture one or more FORJs. At least one further object of the present disclosure is to provide a new optical path configuration(s) to control beams with multiple wavelengths independently so that a compact FORJ with high coupling efficiency may be achieved. A FORJ according to the claims is provided.

In accordance with one or more embodiments of the present disclosure, apparatuses and systems, and methods and storage mediums for use with one or more embodiments of a FORJ may operate to characterize biological objects, such as, but not limited to, blood, mucus, tissue, etc..

In accordance with one or more aspects of the present disclosure, at least one embodiment of a FORJ in an apparatus or system may relate to forward and side views or imaging. Additionally or alternatively, one or more embodiments of a FORJ in an apparatus or system may relate to using a photo diode. At least one embodiment may obtain one or more types of images (e.g., SEE, OCT, etc.).

One or more embodiments of the present disclosure may be used in clinical application(s), such as, but not limited to, intervascular imaging, atherosclerotic plaque assessment, cardiac stent evaluation, balloon sinuplasty, sinus stenting, arthroscopy, ophthalmology, ear research, veterinary use and research, etc..

In accordance with at least another aspect of the present disclosure, the FORJs and one or more technique(s) discussed herein may be employed to reduce the cost of at least one of manufacture and maintenance of the FORJ(s) in one or more devices, systems and storage mediums by reducing or minimizing a number of optical components in an interference optical system, such as an interferometer and/or such as using other light sources including LEDs (e.g., when sensitivity is sufficient and/or meets a predetermined condition, threshold or requirement) to cut down cost.

According to other aspects of the present disclosure, one or more additional devices, one or more systems, one or more methods and one or more storage mediums using, or for use with, one or more FORJs are discussed herein. Further features of the present disclosure will in part be understandable and will in part be apparent from the following description and with reference to the attached drawings.

For the purposes of illustrating various aspects of the disclosure, wherein like numerals indicate like elements, there are shown in the drawings simplified forms that may be employed, it being understood, however, that the disclosure is not limited by or to the precise arrangements and instrumentalities shown. To assist those of ordinary skill in the relevant art in making and using the subject matter hereof, reference is made to the appended drawings and figures, wherein:.

One or more devices, optical systems, methods and storage mediums for imaging using a fiber optic rotary joint, and one or more methods of manufacturing at least one fiber optic rotary joint and/or of manufacturing at least one free space optical beam combiner, are disclosed herein.

Turning now to the details of the figures, <FIG> shows an OCT system <NUM> (as referred to herein as "system <NUM>" or "the system <NUM>") which operates to utilize an OCT technique with optical probe applications in accordance with one or more aspects of the present disclosure. The system <NUM> comprises a light source <NUM>, a reference arm <NUM>, a sample arm <NUM>, a splitter <NUM> (also referred to herein as a "beam splitter"), a reference mirror (also referred to herein as a "reference reflection") <NUM>, and one or more detectors <NUM>. The system <NUM> may include a phase shift device or unit <NUM>. In one or more embodiments, the system <NUM> may include a patient interface device or unit ("PIU") <NUM> and a catheter <NUM> (as diagrammatically shown in <FIG>), and the system <NUM> may interact with a sample <NUM> (e.g., via the catheter <NUM> and/or the PIU <NUM>). In one or more embodiments, the system <NUM> includes an interferometer or an interferometer is defined by one or more components of the system <NUM>, such as, but not limited to, at least the light source <NUM>, the reference arm <NUM>, the sample arm <NUM>, the splitter <NUM> and the reference mirror <NUM>.

The light source <NUM> operates to produce a light to the splitter <NUM>, which splits the light from the light source <NUM> into a reference beam passing into the reference arm <NUM> and a sample beam passing into the sample arm <NUM>. The beam splitter <NUM> is positioned or disposed at an angle to the reference mirror <NUM>, the one or more detectors <NUM> and to the sample <NUM>. The reference beam goes through the phase shift unit <NUM> (when included in a system, as shown in the system <NUM>), and the reference beam is reflected from the reference mirror <NUM> in the reference arm <NUM> while the sample beam is reflected or scattered from a sample <NUM> through the PIU (patient interface unit) <NUM> and the catheter <NUM> in the sample arm <NUM>. Both of the reference and sample beams combine (or recombine) at the splitter <NUM> and generate interference patterns. The output of the system <NUM> and/or the interferometer thereof is continuously acquired with the one or more detectors <NUM>, e.g., such as, but not limited to, photodiodes or multi-array cameras. The one or more detectors <NUM> measure the interference or interference patterns between the two radiation or light beams that are combined or recombined. In one or more embodiments, the reference and sample beams have traveled different optical path lengths such that a fringe effect is created and is measurable by the one or more detectors <NUM>. Electrical analog signals obtained from the output of the system <NUM> and/or the interferometer thereof are converted to digital signals to be analyzed with a computer, such as, but not limited to, the computer <NUM>, <NUM>' (shown in <FIG>, respectively, discussed further below). In one or more embodiments, the light source <NUM> may be a radiation source or a broadband light source that radiates in a broad band of wavelengths. In one or more embodiments, a Fourier analyzer including software and electronics may be used to convert the electrical analog signals into an optical spectrum.

The light source <NUM> may include a plurality of light sources or may be a single light source. The light source <NUM> generates broadband laser lights in one or more embodiments. The light source <NUM> may include one or more of a laser, an organic Light-Emitting Diode (OLED), a Light-Emitting Diode (LED), a halogen lamp, an incandescent lamp, supercontinuum light source pumped by a laser, and/or a fluorescent lamp. The light source <NUM> may be any light source that provides light which can then be split up into at least three bands in which each band is further dispersed to provide light which then used to for spectral encoding of spatial information. The light source <NUM> may be fiber coupled or may be free space coupled to the other components of the system or systems discussed herein, such as, but not limited to, the system <NUM>, the system <NUM>', etc..

In accordance with at least one aspect of the present disclosure, a feature of OCT systems is implemented using fiber optics. As aforementioned, one application of an OCT technique of the present disclosure is to use OCT with a catheter <NUM> as schematically shown in <FIG>.

<FIG> shows at least one embodiment of a system <NUM>' which includes OCT and fluorescence sub-systems. In one or more embodiments, the OCT sub-system includes a light source, such as the light source <NUM>, a splitter (such as the splitter <NUM>; another type of deflecting or deflection device discussed below may be used in place of the splitter <NUM>), one or more circulators <NUM>, a reference reflection (such as the reference reflection <NUM>), a combiner (such as the combiner <NUM>), and at least one detector (such as the at least one detector <NUM>). The OCT sub-system may be connected to, and include, a patient interface unit, such as the PIU <NUM>, and the catheter <NUM> to expose a sample, such as the sample <NUM>, to light and receive information in response thereto. In one or more embodiments, the fluorescence sub-system may include a light source for fluorescence (such as the second light source <NUM> shown in <FIG>) and at least one detector (such as the second at least one detector <NUM> shown in <FIG>). The fluorescence sub-system, including, but not limited to, the second light source <NUM> and the second at least one detector <NUM>, may also be connected to (see <FIG>), and/or include, a patient interface unit, such as the PIU <NUM>, and the catheter <NUM> to expose a sample, such as the sample <NUM>, to fluorescent light and receive information in response thereto. For example, in at least one embodiment, an OCT light with a wavelength of around <NUM> from a light source (such as the light source <NUM> of the OCT sub-system) is delivered and split into a reference arm (e.g., the reference arm <NUM>) and a sample arm (e.g., the sample arm <NUM>) with a splitter (e.g., the splitter <NUM>). A reference beam is reflected from a reference mirror (e.g., the reference reflection <NUM>) in the reference arm (e.g., the reference arm <NUM>) while a sample beam is reflected or scattered from a sample through a PIU (patient interface unit) (such as the PIU <NUM>) and a catheter (e.g., the catheter <NUM>) in the sample arm (e.g., the sample arm <NUM>). Both beams combine at a combiner (e.g., the splitter <NUM> in <FIG>, the combiner <NUM> in <FIG>, etc.) and generate interference patterns. The output of the interferometer is detected with detectors (e.g., the at least one detector <NUM> shown in <FIG>, the at least one detector <NUM> of the OCT subsystem shown in <FIG>, etc.) such as photodiodes or multi-array cameras. Then signals are transferred to a computer (e.g., the computer <NUM> as shown in <FIG> and <FIG>, the computer <NUM>' of <FIG>, etc.) to perform signal processing. The interference patterns are generated only when the path length of the sample arm (e.g., the sample arm <NUM>) matches that of the reference arm (e.g., the reference arm <NUM>) to within the coherence length of the light source (e.g., the light source <NUM> of <FIG>, the light source <NUM> of the OCT sub-system of <FIG>, etc.).

An excitation light with a wavelength (e.g., any predetermined wavelength visible to infrared (IR)), for example, <NUM> from a light source (e.g., the light source <NUM> of the fluorescence sub-system of <FIG>) is delivered to the sample (e.g., the sample <NUM>) through the PIU (e.g., the PIU <NUM>) and the catheter (e.g., the catheter <NUM>). The sample (e.g., the sample <NUM>) emits auto-fluorescence light with broadband wavelengths of, for example, <NUM> - <NUM> by the excitation light. The auto-fluorescence light is collected with the catheter (e.g., the catheter <NUM> of <FIG>) and delivered to detectors (e.g., the detector(s) <NUM> of the fluorescence sub-system of <FIG>) via the PIU (e.g., the PIU <NUM>). Other wavelengths, in the visible and NIR are also contemplated.

<FIG> shows an embodiment of the catheter <NUM> including a sheath <NUM>, a coil <NUM>, a protector <NUM> and an optical probe <NUM>. As shown schematically in <FIG>, the catheter <NUM> preferably is connected to the PIU <NUM> to spin the coil <NUM> with pullback (e.g., at least one embodiment of the PIU <NUM> operates to spin the coil <NUM> with pullback). The coil <NUM> delivers torque from a proximal end to a distal end thereof (e.g., via or by a rotational motor in the PIU <NUM>). In one or more embodiments, the coil <NUM> is fixed with/to the optical probe <NUM> so that a distal tip of the optical probe <NUM> also spins to see an omnidirectional view of a biological organ, sample or material being evaluated, such as, but not limited to, hollow organs such as vessels, a heart, etc. For example, fiber optic catheters and endoscopes may reside in the sample arm (such as the sample arm <NUM> as shown in <FIG>) of an OCT interferometer in order to provide access to internal organs, such as intravascular images, gastro-intestinal tract or any other narrow area, that are difficult to access. As the beam of light through the optical probe <NUM> inside of the catheter <NUM> or endoscope is rotated across the surface of interest, cross-sectional images of one or more samples are obtained. In order to acquire three-dimensional data, the optical probe <NUM> is simultaneously translated longitudinally during the rotational spin resulting in a helical scanning pattern. This translation is most commonly performed by pulling the tip of the probe <NUM> back towards the proximal end and therefore referred to as a pullback.

In at least one embodiment, there is a mirror (e.g., mirror <NUM> of <FIG> as discussed below) at the distal end so that the light beam is deflected outward. In at least one embodiment, the optical probe <NUM> comprises a fiber connector at a proximal end, a double clad fiber and a lens at a distal end. The fiber connector may be connected with the PIU <NUM>. The double clad fiber (see e.g., double clad fiber <NUM> of <FIG> as discussed below) is used to deliver both OCT and fluorescence lights. The lens (see e.g., GRIN lens 501b shown in <FIG> as discussed below) is used for focusing and collecting lights to and/or from the sample (e.g., the sample <NUM>).

In one or more embodiments, the patient user interface <NUM> may comprise or include a connection component (or interface module), such as a rotary junction (e.g., the rotary junction <NUM> as shown schematically in <FIG> and <FIG>, another rotary junction discussed herein, etc.), to connect one or more components, such as one or more components of a probe (e.g., a catheter <NUM> (see e.g., <FIG>)), a needle, a capsule, a patient interface unit (e.g., the patient interface unit <NUM>), etc., to one or more other components, such as, an optical component, a light source (e.g., the light source <NUM>), a deflection section (e.g., such as the deflection or deflected section, which is a component that operates to deflect the light from the light source to the interference optical system, and then send light received from the interference optical system towards the at least one detector; a deflection or deflected section that includes at least one of: one or more interferometers, a circulator, a beam splitter, an isolator, a coupler, a fusion fiber coupler, a partially severed mirror with holes therein, and a partially severed mirror with a tap; etc.), the sample arm <NUM>, a motor that operates to power the connection component and/or the patient user interface <NUM>, etc. For example, when the connection member or interface module is a rotary junction, preferably the rotary junction operates in the same or similar fashion as the rotary junction <NUM> discussed herein). In one or more other embodiments, the rotary junction may be at least one of: a contact rotary junction, a lenseless rotary junction, a lens-based rotary junction, or other rotary junction known to those skilled in the art.

In at least one embodiment, the PIU <NUM> may include a FORJ (such as the rotary joint <NUM> discussed herein), a rotational motor and translation motorized stage (see e.g., portion <NUM> of PIU <NUM> as shown in <FIG>), and a catheter connector (see e.g., portion <NUM> of the PIU <NUM> as shown in <FIG>). The FORJ allows uninterrupted transmission of an optical signal while rotating the double clad fiber (e.g., the DCF <NUM>) along the fiber axis. The FORJ has a free space optical beam combiner consisting of a rotor and stator (see e.g., rotor 306a and stator 306b as shown in <FIG> and as discussed further below). <FIG> shows a configuration of a free space beam combiner and FORJ in accordance with at least one embodiment of the present disclosure. In an OCT and fluorescence system (such as the system <NUM>' as shown in <FIG>), the stator (e.g., the stator 306b of <FIG>) comprises at least two (<NUM>) optical fibers for OCT and excitation (see e.g., single mode fiber 507a of <FIG> that operates for OCT light source delivery and light detection; single mode fiber 507b of <FIG> that operates to work with the excitation light source <NUM> (e.g., light source <NUM> of the fluorescence sub-system or portion of system <NUM>' of <FIG>); etc.). Each fiber has a lens at the beam combiner side of each fiber (e.g., the single mode fiber 507a is connected to a GRIN lens 501a as shown in <FIG>; the multi-mode fiber <NUM> is connected to a GRIN lens 501d as shown in <FIG>; the single mode fiber 507b is connected to a GRIN lens 501c as shown in <FIG>; etc.). The rotor (e.g., the rotor 306a of <FIG>) is made of a double clad fiber (e.g., the double clad fiber <NUM>) with a fiber connection at the catheter (e.g., the catheter <NUM>) side and a lens (e.g., a GRIN lens 501b as shown in <FIG>) at the beam combiner side. Then, the fiber connector of the rotor (e.g., the rotor 306a) is connected to the optical probe (e.g., the optical probe <NUM> via the catheter <NUM> as shown in <FIG>), and the stator (e.g., the stator 306b) is connected to the optical sub-systems (as shown schematically in <FIG>). For example, in at least one embodiment as best seen schematically in <FIG>, the single mode fiber 507a is connected to the OCT light source (e.g., the light source <NUM>) and the detection elements (e.g., the at least one detector <NUM>) of the OCT sub-system, the multi-mode fiber <NUM> is connected to the fluorescence detection elements (e.g., the at least one detector <NUM>) of the fluorescence sub-system), and the single mode fiber 507b is connected to the excitation light source (e.g., the light source <NUM>) of the fluorescence sub-system. The rotational motor (e.g., the rotational motor <NUM>) delivers the torque to the rotor (e.g., the rotor 306a). Also, the translation motorized stage is used for a pullback such that the beam is scanned inside the lumen sample in a helical manner. The catheter connector (e.g., the catheter connector <NUM> as shown schematically in <FIG>) is connected to the catheter (e.g., the catheter <NUM>).

As best seen in <FIG>, OCT light is collimated with a GRIN lens 501a from single mode fiber 507a. The collimated OCT light couples into the core of the double clad fiber <NUM> (of rotor 306a) via a dichroic filter 502a and a GRIN lens 501b. Also, the back scattered OCT light from the sample (e.g., the sample <NUM>) goes back to the rotor 306a (via the catheter <NUM>). The light is collimated with the GRIN lens 501b and couples into the single mode fiber 507a (as shown in <FIG>). In one or more embodiments, the magnification is approximately or about <NUM>, or is <NUM>, in order to couple fiber efficiently because OCT light is delivered with reversible paths (for example, from stator 306b to rotor 306a and from rotor 306a to stator 306b). Coupling efficiency is improved or maximized when having the magnification be approximately or about <NUM>, or be <NUM>.

<FIG> shows at least one embodiment of how to couple OCT and excitation channels into a single core of a double clad fiber in a rotary junction. For example, a fiber optic rotary joint may include a single rotator portion having a double clad fiber (e.g., double clad fiber <NUM>) and a lens (e.g., the lens <NUM> shown in <FIG>) that operates to collimate OCT light. As aforementioned, a stator portion of a rotary joint may include: (i) an OCT portion having a single mode fiber (e.g., the single mode fiber 507a) and a lens (e.g., the lens <NUM> shown in <FIG>) that operates to collimate OCT light, the collimated OCT light coupling into the core of the double clad fiber in the rotator portion; (ii) an excitation stator portion including a single mode fiber (e.g., the single mode fiber 507b) and a lens (e.g., the lens <NUM> shown in <FIG>) that operates to have most of the light images in the middle and then the light couples into the core of the double clad fiber <NUM> in the rotator portion; and (iii) an emission stator portion including a multi-mode fiber <NUM> and a lens (e.g., the lens <NUM> as shown in <FIG>). As shown in <FIG>, at least one embodiment of the rotary joint or junction may include dichroic filters 502a and 502b along with a mirror <NUM>. The longpass filter <NUM> as shown in <FIG> may be optionally used as needed in one or more embodiments, and one or more embodiments (e.g., as shown in <FIG>) may not use the longpass filter <NUM>. The longpass filter <NUM> may be positioned at any predetermined position between the dichroic filter 502b and the GRIN 501d so long as the longpass filter <NUM> operates to appropriately filter light, for example, by attenuating or stopping shorter wavelengths and by passing or transmitting longer wavelengths as discussed herein. In one or more embodiments, use and positioning of the longpass filter <NUM> may be application or sample dependent. Preferably, the longpass filter <NUM> may be used to avoid backward noise and excitation light to achieve a better image when analyzing the fluorescent signal. OCT (e.g., <NUM>) light is collimated by the lens for the OCT channel (e.g., the lens <NUM> for the OCT channel) and by the lens for the rotator channel (e.g., the lens <NUM> for the rotator channel). Focal lengths of both lenses <NUM>, <NUM> are almost or about the same (or may be the same) to minimize insertion losses. Using a small lens for one or more of the lenses <NUM> is preferred to miniaturize the rotator channel. Also, using a small lens for one or more of the lenses <NUM>, <NUM>, <NUM> are preferred to miniaturize the stator channel. In one embodiment, the focal length of the rotator lens <NUM> may be smaller to achieve better chromatic aberration, and in one or more embodiments, the focal length of the rotator lens <NUM> may be longer to be less diverging for fluorescence. A secondary image may be used for excitation coupling, and, as discussed further below, one or more fabrication processes may be easier to achieve active alignment of the distance between a lens and a respective fiber. As aforementioned, a second line or cable may be used for fluorescence, and a third line or cable may be used for excitation. In one or more embodiments, a shorter distance may be used for fluorescence to have less vignetting because of diverse fluorescence light from the rotator channel to the stator channel. The numerical aperture (NA) of the fibers <NUM>, 507a, 507b, <NUM>, mode-field diameter of the fibers <NUM>, 507a, 507b, <NUM> and lens relationship are determined to, preferably maximize (or at least increase or improve) coupling efficiencies for OCT, excitation and fluorescence lights. For OCT, the same or similar focal lengths of lenses <NUM>, <NUM> are used. For excitation, one or more embodiments may meet the following conditions: Mex= |frot/fex| ≤ |MFDdcf / MFDex|, |γex| ≤ NAdcf / NAex, where frot is the focal length of the lens <NUM>, where fex is the focal length of the lens <NUM>, MFDdcf is the core mode field diameter of the double clad fiber <NUM>, MFDexis the core mode field diameter of the excitation fiber 507b, Mex is lateral magnification, and γex is angular magnification. The lateral and angular magnifications meet the following relationship: Mex x γex = <NUM> so that |Mex|=|<NUM>/γex| ≥ NAex / NAdcf. For fluorescence, one or more embodiments may meet the following condition(s): Core diameter of multi-mode fiber <NUM> ≥ Clad diameter of double clad fiber <NUM> x Mem, where Mem is the lateral magnification between lenses <NUM> and <NUM>, and meets the following relationship Mem= |fem/frot|, where fem is the focal length of the lens <NUM>.

In one or more embodiments, excitation light of <NUM> wavelength from the single mode fiber 507b is converged with a GRIN lens 501c. The light is focused at the middle, or at a predetermined position (see e.g., focusing position <NUM> shown in <FIG>) of the optical path to the GRIN lens 501b, and then the light is coupled into mostly the core of the double clad fiber <NUM> with the GRIN lens 501b, as shown in <FIG> and <FIG>. Also, in one or more embodiments, the lateral magnification (Mex) is less than or equal to the mode-field diameter (MFD) ratio of the core of the double clad fiber <NUM> (MFDdcf) and the single mode fiber 507b (MFDex) in order to couple efficiently into the core of double clad fiber <NUM>. In other words, |Mex| ≤ MFDdcf / MFDex. Also, in one or more embodiments, the angular magnification is less than (or less than or equal to as discussed below) the NA (numerical aperture) ratio of the single mode fiber 507b (NAex) and the core of the double clad fiber <NUM> (NAdcf) in order to achieve high coupling efficiency. In other words, |γ| ≤ NAdcf / NAex. In one or more further embodiments, the magnification may be less than or equal to the NA (numerical aperture) ratio of the single mode fiber 507b (NAex) and the core of the double clad fiber <NUM> (NAdcf) in order to achieve high coupling efficiency. In other words, |γ| ≤ NAdcf / NAex. For example, when a single mode fiber with MFDexof <NUM> and NAex of <NUM> and a double clad fiber with MFDdcf of <NUM> and NAdcf of <NUM> are used, the lateral magnification with more than or equal to <NUM> and less than or equal to <NUM> are desired to increase coupling efficiency.

Fluorescence light from mostly the cladding of the double clad fiber <NUM> is delivered through GRIN lens 501b, as shown in <FIG>. The light is diverged due to the cladding diameter and coupled into a multi-mode fiber (e.g., the fiber <NUM> as shown in <FIG>) via a GRIN lens 501d (as shown in <FIG> and <FIG>). In at least one embodiment, high coupling efficiency is achieved with a lateral magnification (Mem) that is less than or equal to the ratio of the core diameter of the multi-mode fiber <NUM> (Dmm) and the cladding diameter <NUM> (Ddcf). In other words, Mem ≤ Dmm / Ddcf.

In at least one embodiment, the OCT light is collimated with GRIN lens 501a and GRIN lens 501b, respectively, in order to achieve less sensitivity when aligning the distances between GRIN lens 501a and GRIN lens 501b. The excitation light, which, in at least one embodiment, is a shorter wavelength than the wavelength of the OCT light, converges and is focused by GRIN lens 501c to an intermediate focus (see e.g., the focusing position <NUM> of <FIG>), and then coupled substantially (e.g., <NUM>%, about <NUM>%, <NUM>%, <NUM>%, about <NUM>% to about <NUM>%, etc.) into the core of the double clad fiber <NUM>. In this configuration, the excitation light couples efficiently into the core of double clad fiber <NUM>, and also the alignment of GRIN lens 501c and single mode fiber 507b becomes easier because GRIN lens 501c and single mode fiber 507b are assembled separately with the assembly of GRIN lens 501b. One or more embodiments of fabrication processes are discussed below.

In some embodiments, the excitation light is a shorter wavelength than the wavelength of the OCT light. For example, the excitation light is at least <NUM>%, <NUM>%, or <NUM>% shorter than the wavelength of the OCT light. Thus, with visible and NIR excitation, the wavelength of the excitation light is, in an exemplary embodiment, at least <NUM> shorter than the wavelength of the OCT light. In one or more alternative embodiments, the excitation light may have a greater wavelength than the wavelength of the OCT light.

In one or more embodiments, as best seen in <FIG>, dichroic filter 502a is used for separating OCT light from the rest of excitation and fluorescence light. Dichroic filter 502b is used for a separation of the excitation and fluorescence light. The mirror <NUM> is used to reflect the excitation light. The long-pass filter <NUM> may be used to filter out back-reflection and/or stray light of excitation light.

Also, the optical path lengths of OCT (Loct), fluorescence (Lfl) and excitation (Lex) light are designed, in at least one embodiment, with the following condition: Loct < Lfl < Lex. In one or more embodiments, it is preferred to have the OCT optical path length be as short as possible to improve and/or maximize coupling efficiency. It may be difficult to achieve a collimated beam that has a beam waist far (in one or more embodiments, a far beam waist depends on the lens size and quality; for example, in one or more embodiments, > <NUM> beam waist may be far whereas, in other embodiments, > <NUM> beam waist may not be far) from the collimator lens (see e.g., lens <NUM> or lens <NUM> of <FIG>). In at least one embodiment (best seen in <FIG>), excitation light is focused at the middle, or at a predetermined location (e.g., focusing position <NUM>), of the optical path so a longer optical path length may be designed. Fluorescence light is diverged (or diverges) and has a large diameter beam, so, in one or more embodiments, it is preferred to shorten the optical path length of fluorescence light.

In at least one embodiment, wavelengths of excitation light with <NUM>-<NUM> and fluorescence light with <NUM>-<NUM> are chosen based on targeted markers. Collagen and/or elastin with an excitation wavelength of <NUM>-<NUM> and auto-fluorescence of <NUM>-<NUM> are utilized. Lipid and/or fat may be detected with the excitation wavelength of <NUM>-<NUM> and fluorescence wavelength of <NUM>-<NUM>. ICG (Indocyanine green) marker is used with excitation light with <NUM>-<NUM> wavelength and fluorescence light with <NUM>-<NUM>. Any other auto-fluorescence marker(s) and fluorescence dye(s) may be utilized with one or more embodiments of the present disclosure.

In one or more alternative embodiments, a free space beam combiner, which is located inside an FORJ, may be provided as shown in <FIG>. The embodiment of <FIG> is the same as the embodiment shown in <FIG>, with the following exceptions: the stator 306b' of the rotary junction <NUM>' in <FIG> includes two optical fibers (and not three) because the multi-mode fiber <NUM> and the GRIN lens 501d are removed, and the stator 306b' of the rotary junction <NUM>' includes a double clad fiber <NUM> being used with GRIN lens 501a (instead of the single mode fiber 507a as shown in <FIG>). OCT light goes through the core of the double clad fiber <NUM> in the stator <NUM>', and is then collimated with the GRIN lens 501a. The collimated light is coupled into the core of the double clad fiber <NUM> in the rotor 306a'. Excitation light, with wavelength shorter than that of OCT light, is converged and focused with the GRIN lens 501c at the middle (or at a predetermined position) of the optical path to GRIN lens 501b. Then, the light is coupled into mostly the core of the double clad fiber <NUM> in the rotor 306a' of the rotary junction <NUM>'. Fluorescence light from the sample (e.g., the sample <NUM>) is delivered through mostly the clad of the double clad fiber <NUM> in rotor 306a'. Then, the light is coupled into the clad of the double clad fiber <NUM> in the stator 306b'. To separate OCT light and fluorescence light, a double clad fiber coupler may be used either inside the PIU <NUM> or in the imaging subsystem. Dichroic filter <NUM> of <FIG> is used to separate excitation light and the rest of fluorescence and OCT lights. The double clad fiber <NUM> of the stator 306b' is connected to a core/clad beam splitter to separate OCT and fluorescence light. As such, a simple and compact FORJ may be achieved with this configuration because of a lack of the free-space optical fluorescence channel. Also, it is easier to fabricate the beam combiner because OCT and fluorescence lights are coupled using a common double clad fiber (e.g., the fiber <NUM>). The FORJ <NUM>' may be used in place of the FORJ <NUM> as discussed above as shown schematically in <FIG>. In one or more embodiments, a mirror, a ferrule, a sleeve and/or epoxy as discussed in the present disclosure may be optional, and the fibers, lenses and a dichroic filter may be used without one or more of the mirror, the ferrule, the sleeve and/or the epoxy.

Descriptions of like-numbered elements present in the system <NUM>' and/or the rotary junction <NUM>' and already described above, such as for the system <NUM> and/or the rotary junction <NUM>, shall not be repeated.

In at least one embodiment, the console <NUM>, <NUM>' operates to control motions of the motor and translation motorized stage (hereinafter referred to as "motor" or "motor and stage") <NUM>, acquires intensity data from the at least one detector(s) <NUM>, and displays the scanned image (e.g., on a monitor or screen such as a display, screen or monitor <NUM> as shown in the console <NUM> of <FIG> and/or the console <NUM>' of <FIG> as further discussed below). In one or more embodiments, the console <NUM>, <NUM>' operates to change a speed of the motor <NUM> and/or to stop the motor <NUM>. The motor <NUM> may be a stepping or a DC servo motor to control the speed and increase position accuracy.

In one or more embodiments, the console or computer <NUM>, <NUM>' operates to control motions of the rotary junction <NUM>, the rotary junction <NUM>', the motor <NUM>, the catheter <NUM> and/or one or more other above-described components of the system <NUM> and/or the system <NUM>'. In at least one embodiment, the console or computer <NUM>, <NUM>' operates to acquire intensity data from the at least one detector <NUM> of the OCT sub-system and the fluorescence sub-system, and displays the image(s) (e.g., on a monitor or screen such as a display, screen or monitor <NUM> as shown in the console <NUM> of <FIG> and/or the console <NUM>' of <FIG> as further discussed below). The output of the one or more components of the system <NUM> and/or the system <NUM>' is acquired with the at least one detector <NUM> of the OCT sub-system and with the at least one detector <NUM> of the fluorescence sub-system, e.g., such as, but not limited to, photodiodes, Photomultiplier tube(s) (PMTs), line scan camera(s), or multi-array camera(s). Electrical analog signals obtained from the output of the system <NUM> and/or the system <NUM>' or one or more components thereof are converted to digital signals to be analyzed with a computer, such as, but not limited to, the computer <NUM>, <NUM>' (e.g., as shown in <FIG> and <FIG>). In one or more embodiments, the light source <NUM> may be a radiation source or a broadband light source that radiates in a broad band of wavelengths. In one or more embodiments, a Fourier analyzer including software and electronics may be used to convert the electrical analog signals into an optical spectrum. In some embodiments, the at least one detector <NUM> comprises three detectors configured to detect three different bands of light.

In accordance with at least one aspect of the present disclosure and as aforementioned, one or more methods for manufacturing or making a fiber optic rotary joint (and/or one or more components thereof) are provided herein. <FIG> illustrates a flow chart of at least one embodiment of a method for making one or more components of at least one embodiment of a FORJ. Preferably, the method(s) may include one or more of the following: (i) insert a stripped single mode fiber (see e.g., stripped fiber 900b in portion of <FIG> corresponding to step S801 of <FIG>; see e.g., single mode fiber 507a as aforementioned) into a ferrule (see e.g., ferrule <NUM> in <FIG>) and glue with an epoxy (see e.g., epoxy <NUM> in <FIG>) to hold the fiber and ferrule together (see step S801 of <FIG>); (ii) polish the ferrule at about or by a predetermined degree(s) (e.g., at or about <NUM> degrees) (see step S802 in <FIG>; see also, e.g., ferrule <NUM> in portion of <FIG> corresponding to step S802); (iii) polish a GRIN (e.g., the GRIN 501a or 501b) at about or by the predetermined degree(s) (e.g., at or about <NUM> degrees) on a side (see step S803 of <FIG>; see also, e.g., GRIN 501a, 501b in portion of <FIG> corresponding to step S803); (iv) fix the polished GRIN (e.g., the GRIN 501a or 501b) inside a sleeve (e.g., sleeve <NUM> of <FIG> portion corresponding to step S804) with epoxy (e.g., epoxy <NUM> shown in <FIG> portion corresponding to step S804) (see step S804 of <FIG>); and (v) put gradient index matching (or substantially matching) epoxy (see e.g., the epoxy <NUM> located in between the polished ferrule <NUM> and the GRIN (e.g., the GRIN 501a or 501b) inside the sleeve <NUM> of the portion of <FIG> that corresponds to step S805) and polished ferrule (see e.g., the polished ferrule <NUM>) at another side (e.g., on the left side of the sleeve <NUM>) of the polished GRIN (e.g., the GRIN 501a or 501b) and cure the epoxy (e.g., the epoxy <NUM> at the left side of the sleeve <NUM>) at a predetermined or certain distance of the GRIN (e.g., the GRIN 501a or 501b) and the ferrule (e.g., the ferrule <NUM>) (e.g., in one or more embodiments, the predetermined or certain distance may be about <NUM>, about <NUM> - about <NUM>, or any other desired distance depending on the application) to achieve a collimated beam (see step S805 of <FIG>). The fiber 900a may include a jacket <NUM>(<NUM>) as shown in <FIG>. In one or more embodiments, the GRIN surface and/or the ferrule surface may be designed at any desirable angle depending on the application for use. In one or more embodiments, the angle of the GRIN 501b and/or GRIN 501a, and/or the ferrule surface, is in the <NUM>-<NUM> degree range.

In one or more embodiments, the surfaces of the single mode fiber (see e.g., the stripped fiber 900b) and the GRIN lens (e.g., the GRIN 501a or 501b) are tilted by the predetermined number of degrees to reduce back-reflection. Gradient index matching (or substantially matching) materials may be placed between the surfaces to reduce the back-reflection. The collimated beam is achieved with the GRIN lens 501a from the single mode fiber (e.g., the single mode fiber 507a as discussed above) to align the distance of the GRIN lens 501a and the fiber 507a.

The method <NUM> of fabricating a FORJ may further include creating a second GRIN lens (e.g., the GRIN 501b), or creating a second GRIN collimator, by repeating the steps S801-S805 for the second GRIN lens, with the exception being that a different fiber material is used. For example, for GRIN 501b, the aforementioned double clad fiber <NUM> is used instead of a single mode fiber. The surfaces of the double clad fiber <NUM> and the GRIN 501b may also be tilted by the predetermined number of degrees (e.g., by or about <NUM> degrees), and the gradient index matching (or substantially matching) material(s) may be placed between the angled or tilted surfaces of the double clad fiber <NUM> and the GRIN 501b. In at least one embodiment, a collimated beam is achieved with the GRIN lens 501b from the core of the double clad fiber <NUM>. In one or more embodiments, the GRIN lens 501a and the GRIN lens 501b have approximately the same or the same focal length to achieve magnification of approximately or about <NUM>, or <NUM>, to increase throughput.

The method <NUM> of fabricating a FORJ may further include creating a third GRIN lens (e.g., the GRIN 501c), or creating a third GRIN collimator fiber. In one or more embodiments, the GRIN collimator (e.g., the GRIN 501c) is fabricated with an active alignment method. A portion of the GRIN 501c may be formed or created using the aforementioned steps regarding a single mode fiber and portions thereof 900a, 900b, <NUM> and the fixing of same inside a sleeve <NUM> using epoxy <NUM> (see such components and the same or similar configuration as shown in <FIG>). As such, the details of such manufacturing steps are not repeated. The distance between the GRIN 501c and the single mode fiber 507b is aligned to observe a focus position with a camera <NUM>, as best seen in <FIG>. In at least one embodiment, the camera <NUM> is placed at the designed certain, or predetermined, distance from GRIN lens 501c, and then a spot size of lights is observed. While changing the distance between GRIN lens 501c and the fiber (see e.g., the stripped portion of the fiber 900b as shown in <FIG>), the distance is fixed when the minimum spot size is observed (see middle portion (b) of <FIG>). In contrast, the distance is adjusted when the spot size is large due to converged beams crossing paths (as shown in top portion (a) of <FIG>) or converging beams not yet being converged (and, therefore, are spaced apart or separated) (as shown in the bottom portion (c) of <FIG>). With the active alignment method, the GRIN 501c collimator is separately fabricated with the GRIN 501b collimator so that these components are easier to fabricate. Also, this fabrication process may achieve a reduction in alignment time.

In one or more embodiments, the method <NUM> of fabricating a FORJ may further include creating a fourth GRIN lens (e.g., the GRIN 501d), or creating a fourth GRIN collimator fiber. A portion of the GRIN 501d may be formed or created using the aforementioned steps regarding fiber fabrication (using a multi-mode fiber, such as the fiber <NUM>, instead of a single mode fiber) and the fixing of a stripped portion of the multi-mode fiber <NUM> inside a sleeve <NUM> using epoxy <NUM> (see such components and the same or similar configuration as shown in <FIG>). As such, the details of such manufacturing steps are not repeated. Moreover, the GRIN 501d collimator is aligned such that the GRIN 501d and the multi-mode fiber <NUM> may be glued together (e.g., the fiber <NUM> and the GRIN 501d are touching when glued together). In one or more embodiments, the GRIN 501d and the multi-mode fiber <NUM> may touch when glued together. In one or more further embodiments, the GRIN 501d and the multi-mode fiber <NUM> may have air in between when glued together.

Moreover, the method <NUM> may further include steps to align the GRIN 501a, 501b, 501c, 501d collimators. Preferably, in at least one embodiment, the GRIN 501b collimator is aligned to match (or substantially match) an optical axis and/or mechanical axis of the FORJ <NUM> or <NUM>' to reduce or minimize rotational variation(s) of insertion loss(es). Then, the rest of the GRIN 501a, 501c, 501d collimators may be mounted to increase or maximize coupling efficiency with tilt and position alignments as discussed herein and as shown in <FIG> and 9a-<NUM>. Any dichroic filter(s) (e.g., dichroic filter <NUM>, filter 502a, filter 502b, etc.) and/or any mirror(s) (e.g., the mirror <NUM>) may be aligned with the GRIN 501a, 501b, 501c, and/or 501d collimators to achieve increased or maximum coupling efficiency with tilt and position alignments as aforementioned.

A computer, such as the console or computer <NUM>, <NUM>', may perform any of the aforementioned steps (e.g., steps S801-S805 for GRIN 501a; repetition of steps S801-S805 for GRIN 501b; the aforementioned steps for GRIN 501c; the aforementioned steps for GRIN 501d and/or alignment of the constructed collimators for GRINs 501a, 501b, 501c and/or 501d; etc.), for any system or FORJ being manufactured, including, but not limited to, system <NUM>, system <NUM>', FORJ <NUM>, FORJ <NUM>', etc..

In one or more embodiments, a SEE probe and/or system may use a FORJ (e.g., the FORJ <NUM>, the FORJ <NUM>', etc.) with a connection member or interface module. For example, the connection member or interface module may include a rotary junction for either a SEE probe. In such a SEE system, the rotary junction may be at least one of: a contact rotary junction, a lenseless rotary junction, a lens-based rotary junction, a rotary junction as described herein, etc. The rotary junction may be a one channel rotary junction or a two channel rotary junction. By way of at least one example, in a SEE device one or more light sources may be used, and the light may be split into at least two (<NUM>) wavelength ranges for use with one or more embodiments of a FORJ of the present disclosure.

Unless otherwise discussed herein, like numerals indicate like elements. For example, while variations or differences exist between FORJs and/or the systems, such as, but not limited to, the FORJ <NUM>, the FORJ <NUM>', the system <NUM>, the system <NUM>', etc., one or more features thereof may be the same or similar to each other, such as, but not limited to, the light source <NUM> or other component(s) thereof (e.g., the console <NUM>, the console <NUM>', etc.). Those skilled in the art will appreciate that the light source <NUM>, the at least one detector <NUM> and/or one or more other elements of the system <NUM>, may operate in the same or similar fashion to those like-numbered elements of one or more other systems, such as, but not limited to, the system <NUM>,'as discussed herein. Those skilled in the art will appreciate that alternative embodiments of the system <NUM>, the system <NUM>', FORJ <NUM>, FORJ <NUM>' and/or one or more like-numbered elements of one of such systems or FORJs, while having other variations as discussed herein, may operate in the same or similar fashion to the like-numbered elements of any of the other systems (or component(s) thereof) or FORJs (or component(s) thereof) discussed herein. Indeed, while certain differences exist between the system <NUM> and the system <NUM>', and between FORJ <NUM> and FORJ <NUM>', as discussed herein, there are similarities. Likewise, while the console or computer <NUM> may be used in one or more systems (e.g., the system <NUM>, the system <NUM>', a system for manufacturing an FORJ (e.g., the FORJ <NUM>, the FORJ <NUM>', etc.), etc.) and/or to control an FORJ (e.g., the FORJ <NUM>, the FORJ <NUM>', etc.), one or more other consoles or computers, such as the console or computer <NUM>', may be used additionally or alternatively.

There are many ways to compute rotation, intensity, or any other measurement discussed herein, and/or to control and/or manufacture an FORJ, digital as well as analog. In at least one embodiment, a computer, such as the console or computer <NUM>, <NUM>', may be dedicated to control and monitor a FORJ and devices, systems, methods and/or storage mediums for use therewith described herein.

Various components of a computer system <NUM> (see e.g., the console or computer <NUM> as shown in <FIG>) are provided in <FIG>. A computer system <NUM> may include a central processing unit ("CPU") <NUM>, a ROM <NUM>, a RAM <NUM>, a communication interface <NUM>, a hard disk (and/or other storage device) <NUM>, a screen (or monitor interface) <NUM>, a keyboard (or input interface; may also include a mouse or other input device in addition to the keyboard) <NUM> and a BUS or other connection lines (e.g., connection line <NUM>) between one or more of the aforementioned components (e.g., as shown in <FIG>). In addition, the computer system <NUM> may comprise one or more of the aforementioned components. For example, a computer system <NUM> may include a CPU <NUM>, a RAM <NUM>, an input/output (I/O) interface (such as the communication interface <NUM>) and a bus (which may include one or more lines <NUM> as a communication system between components of the computer system <NUM>; in one or more embodiments, the computer system <NUM> and at least the CPU <NUM> thereof may communicate with the one or more aforementioned components of a FORJ or a device or system using same, such as, but not limited to, the system <NUM> and/or the system <NUM>', discussed herein above, via one or more lines <NUM>), and one or more other computer systems <NUM> may include one or more combinations of the other aforementioned components. The CPU <NUM> is configured to read and perform computer-executable instructions stored in a storage medium. The computer-executable instructions may include those for the performance of the methods and/or calculations described herein. The computer system <NUM> may include one or more additional processors in addition to CPU <NUM>, and such processors, including the CPU <NUM>, may be used for controlling and/or manufacturing a FORJ, and/or a device, system or storage medium for use with same. The system <NUM> may further include one or more processors connected via a network connection (e.g., via network <NUM>). The CPU <NUM> and any additional processor being used by the system <NUM> may be located in the same telecom network or in different telecom networks (e.g., performing FORJ manufacturing and/or use technique(s) may be controlled remotely).

The I/O or communication interface <NUM> provides communication interfaces to input and output devices, which may include the light source <NUM>, a FORJ (e.g., the FORJ <NUM>, the FORJ <NUM>', etc.), a microphone, a communication cable and a network (either wired or wireless), a keyboard <NUM>, a mouse (see e.g., the mouse <NUM> as shown in <FIG>), a touch screen or screen <NUM>, a light pen and so on. The Monitor interface or screen <NUM> provides communication interfaces thereto.

Any methods and/or data of the present disclosure, such as the methods for using and/or manufacturing a FORJ, and/or a device, system or storage medium for use with same, as discussed herein, may be stored on a computer-readable storage medium. A computer-readable and/or writable storage medium used commonly, such as, but not limited to, one or more of a hard disk (e.g., the hard disk <NUM>, a magnetic disk, etc.), a flash memory, a CD, an optical disc (e.g., a compact disc ("CD") a digital versatile disc ("DVD"), a Blu-ray™ disc, etc.), a magneto-optical disk, a random-access memory ("RAM") (such as the RAM <NUM>), a DRAM, a read only memory ("ROM"), a storage of distributed computing systems, a memory card, or the like (e.g., other semiconductor memory, such as, but not limited to, a non-volatile memory card, a solid state drive (SSD) (see SSD <NUM> in <FIG>), SRAM, etc.), an optional combination thereof, a server/database, etc. may be used to cause a processor, such as, the processor or CPU <NUM> of the aforementioned computer system <NUM> to perform the steps of the methods disclosed herein. The computer-readable storage medium may be a non-transitory computer-readable medium, and/or the computer-readable medium may comprise all computer-readable media, with the sole exception being a transitory, propagating signal. The computer-readable storage medium may include media that store information for predetermined or limited or short period(s) of time and/or only in the presence of power, such as, but not limited to Random Access Memory (RAM), register memory, processor cache(s), etc. Embodiment(s) of the present disclosure may also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a "non-transitory computer-readable storage medium") to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s).

In accordance with at least one aspect of the present disclosure, the methods, systems, and computer-readable storage mediums related to the processors, such as, but not limited to, the processor of the aforementioned computer <NUM>, the processor of computer <NUM>', etc., as described above may be achieved utilizing suitable hardware, such as that illustrated in the figures. Functionality of one or more aspects of the present disclosure may be achieved utilizing suitable hardware, such as that illustrated in <FIG>. Such hardware may be implemented utilizing any of the known technologies, such as standard digital circuitry, any of the known processors that are operable to execute software and/or firmware programs, one or more programmable digital devices or systems, such as programmable read only memories (PROMs), programmable array logic devices (PALs), etc. The CPU <NUM> (as shown in <FIG>) may also include and/or be made of one or more microprocessors, nanoprocessors, one or more graphics processing units ("GPUs"; also called a visual processing unit ("VPU")), one or more Field Programmable Gate Arrays ("FPGAs"), or other types of processing components (e.g., application specific integrated circuit(s) (ASIC)). Still further, the various aspects of the present disclosure may be implemented by way of software and/or firmware program(s) that may be stored on suitable storage medium (e.g., computer-readable storage medium, hard drive, etc.) or media (such as floppy disk(s), memory chip(s), etc.) for transportability and/or distribution. The computer may include a network of separate computers or separate processors to read out and execute the computer executable instructions.

As aforementioned, hardware structure of an alternative embodiment of a computer or console <NUM>' is shown in <FIG>. The computer <NUM>' includes a central processing unit (CPU) <NUM>, a graphical processing unit (GPU) <NUM>, a random access memory (RAM) <NUM>, a network interface device <NUM>, an operation interface <NUM> such as a universal serial bus (USB) and a memory such as a hard disk drive or a solid state drive (SSD) <NUM>. Preferably, the computer or console <NUM>' includes a display <NUM>. The computer <NUM>' may connect with a rotary junction (e.g., the FORJ <NUM>, the FORJ <NUM>', etc.), the motor <NUM> and/or one or more other components of a system (e.g., the system <NUM>, the system <NUM>', etc.) via the operation interface <NUM> or the network interface <NUM>. A computer, such as the computer <NUM>', may include the FORJ <NUM> or <NUM>' and/or the motor <NUM> in one or more embodiments. The operation interface <NUM> is connected with an operation unit such as a mouse device <NUM>, a keyboard <NUM> or a touch panel device. The computer <NUM>' may include two or more of each component. Alternatively, the CPU <NUM> or the GPU <NUM> may be replaced by the fieldprogrammable gate array (FPGA), the application-specific integrated circuit (ASIC) or other processing unit depending on the design of a computer, such as the computer <NUM>, the computer <NUM>', etc..

A computer program is stored in the SSD <NUM>, and the CPU <NUM> loads the program onto the RAM <NUM>, and executes the instructions in the program to perform one or more processes described herein, as well as the basic input, output, calculation, memory writing and memory reading processes.

The computer, such as the computer <NUM>, <NUM>', communicates with the PUI <NUM>, the rotary junction (e.g., the rotary junction <NUM>, the rotary junction <NUM>', etc.), the motor <NUM>, the catheter <NUM> and/or one or more other components of a system, such as the system <NUM>, <NUM>', etc., to perform imaging, and reconstructs an image from the acquired intensity data. The monitor or display <NUM> displays the reconstructed image, and may display other information about the imaging condition or about an object to be imaged. The monitor <NUM> also provides a graphical user interface for a user to operate a system (e.g., the system <NUM>, the system <NUM>', etc.), for example when performing OCT or other imaging technique. An operation signal is input from the operation unit (e.g., such as, but not limited to, a mouse device <NUM>, a keyboard <NUM>, a touch panel device, etc.) into the operation interface <NUM> in the computer <NUM>', and corresponding to the operation signal the computer <NUM>' instructs the system (e.g., the system <NUM>, the system <NUM>', etc.) to set or change the imaging condition, and to start or end the imaging. The laser source <NUM> of an OCT sub-system and/or the laser source <NUM> of a fluorescence sub-system as aforementioned may have interfaces to communicate with the computers <NUM>, <NUM>' to send and receive the status information and the control signals.

The present disclosure and/or one or more components of devices, systems and storage mediums, and/or methods, thereof also may be used in conjunction with any suitable optical assembly including, but not limited to, SEE probe technology, such as in <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>and Patent Application Publication Nos. <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

Similarly, the present disclosure and/or one or more components of devices, systems and storage mediums, and/or methods, thereof also may be used in conjunction with optical coherence tomography probes. Such probes include, but are not limited to, the OCT imaging systems disclosed in <CIT>; <CIT>; and <CIT> and arrangements and methods of facilitating photoluminescence imaging, such as those disclosed in <CIT>, as well as the disclosures directed to multimodality imaging disclosed in <CIT> and <CIT>, <CIT>and <CIT>.

Claim 1:
A fiber optic rotary joint (<NUM>, <NUM>') comprising:
a free space optical beam combiner (<NUM>, 502a, 502b, <NUM>);
a rotor (306a, 306a') that operates to rotate and that includes a common optical fiber (<NUM>) connected to or part of the beam combiner;
a stator (306b, 306b') that operates to be stationary in the fiber optic rotary joint and that includes at least two optical fibers (507a, 507b), a first of the at least two optical fibers operating to guide at least a first light and being connected to or part of the beam combiner and a second of the at least two optical fibers operating to guide a second light and being connected to or part of the beam combiner, the first light being an imaging modality light or light used to perform Optical Coherence Tomography OCT and the second light being an excitation light,
wherein the beam combiner operates to combine the first and second lights from the at least two optical fibers such that the combined light couples, or substantially couples, into a core of the common optical fiber.