Patent Description:
In a wide variety of medical procedures, laser light is used to assist the procedure and treat patient anatomy. For example, in laser photocoagulation, a laser probe is used to cauterize blood vessels on the retina. Some laser probes include an optical fiber cable containing one fiber for delivering laser light to the surgical site, and a separate fiber for simultaneously delivering illumination light during an eye surgery procedure, for instance, during a bimanual operation. In such cases, one of the two fibers is connected to a laser source to deliver the laser beam, and the other fiber is connected to an illumination source for illumination light. The two fibers are then combined and tightly packed within a tube of the optical fiber cable to minimize the size of the optical fiber cable and, therefore, the size of the probe tip where the optical fiber cable is placed. Using a probe tip with a smaller gauge size is advantageous because it facilitates minimization of incision size on the eye (for example, mini-invasive eye surgery), and helps patients recover faster post-surgery.

However, an optical fiber cable containing a laser fiber as well as an illumination fiber can only be made so narrow, because there must be room for both the illumination fiber and the laser fiber to be placed side-by-side in the tube. Narrowing of the two fibers themselves results in lower laser coupling efficiency and insufficient illumination to perform the medical procedure. Further, the fabrication of the probe for integrating the two separate fibers (where one fiber is for the laser beam, and the other fiber is for the illumination light), is complicated, and the cost of manufacturing the probe is high. In addition, the thermal robustness of the probe is an issue at high laser powers due to the plastic fiber used for illumination light, and the adhesive used to bind the fibers together at the distal end of the probe.

Therefore, what is needed in the art is an improved single fiber illuminated laser probe having a high-angle illumination output while maintaining high laser coupling efficiency.

Reference is made to the documents <CIT>, <CIT>, <CIT>, <CIT>, and <CIT> which have been cited as exemplary of the state of the art. <CIT> discloses a multi-spot laser probe with a a multi-core optical fiber cable, comprising a core, an outer cladding circumferentially surrounding the core, and a coating circumferentially surrounding the outer cladding.

According to certain embodiments, a laser probe assembly is provided, including a probe body shaped and sized for grasping by a user, and a probe tip housing a fiber having a proximal end face and a distal end face opposite the proximal end face. The fiber further includes a core, an outer cladding circumferentially surrounding the core, and a coating circumferentially surrounding the outer cladding. The core is configured to transmit a laser light beam and an illumination light. The outer cladding is configured to transmit an illumination light. At least a surface area of the proximal end face or the distal end face of the fiber corresponding to the outer cladding is roughened.

According to certain embodiments, a fiber is provided, including a proximal end face at a proximal end of the fiber and a distal end face at a distal end of the fiber. The fiber further includes a core, an outer cladding circumferentially surrounding the core, and a coating circumferentially surrounding the outer cladding. The core is configured to transmit a laser light beam and an illumination light. The outer cladding is configured to transmit the illumination light. At least a surface area of the proximal end face or the distal end face of the fiber corresponding to the outer cladding is roughened.

It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, and may admit to other equally effective embodiments.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the Figures.

In the following description, details are set forth by way of example to facilitate an understanding of the disclosed subject matter. It should be apparent to a person of ordinary skill in the field, however, that the disclosed implementations are exemplary and not exhaustive of all possible implementations. Thus, it should be understood that reference to the described examples is not intended to limit the scope of the disclosure. Any alterations and further modifications to the described devices, instruments, methods, and any further application of the principles of the present disclosure are fully contemplated as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one implementation may be combined with the features, components, and/or steps described with respect to other implementations of the present disclosure.

Embodiments of the present disclosure generally relate to fibers and laser probe assemblies for surgical procedures. A fiber includes a core that transmits a laser light beam, and the core and an outer cladding surrounding the core that transmit illumination light. A laser probe assembly includes a fiber, and the laser probe assembly allows the user to direct a laser light beam and illumination light simultaneously in a single fiber. Furthermore, one or more end faces (e.g., surfaces) of the fiber may be treated to increase the illumination output (e.g., spreading) angle of the fiber. Generally, the end faces may be treated at least one of two ways to attain such an effect. In certain examples, one or more end faces of the fiber are treated with a roughening process to increase illumination light scattering characteristics of the treated end face(s). In certain examples, one or more end faces are angled by a polishing process to increase illumination light scattering characteristics of the treated end face(s). The end face treatment, whether it includes roughening and/or angling, may be limited to a surface area of the one or more end faces corresponding to the outer cladding, thus only affecting the propagation of illumination light from the fiber. Accordingly, the illumination output angle of the fiber may be increased, while laser beam efficiency and laser beam spot size remain unaffected to maintain photocoagulation performance. The combination of the transmission of laser light and illumination light in the same fiber with treated end-surface(s) results in a more compact optical fiber cable having improved illumination, allowing for enhanced visibility during medical procedures that require a smaller gauge probe. Embodiments of the disclosure may be especially useful for, but are not limited to, a fiber that can transmit both laser light and wide-angle illumination light.

As used herein, the term "about" may refer to a +/-<NUM>% variation from the nominal value. It is to be understood that such a variation can be included in any value provided herein.

<FIG> illustrates a plan view of a system <NUM> for generating an illumination beam as well as a laser light beam for delivery to a surgical target, in accordance with certain embodiments of the present disclosure. As shown, system <NUM> includes a surgical laser system <NUM> and a probe <NUM>. The system <NUM> produces an illumination beam <NUM> and a laser light beam <NUM> to be delivered, for example, to the retina <NUM> of a patient's eye <NUM>.

The surgical laser system <NUM> includes a number of laser light sources (e.g., one or more laser light sources) for generating laser light beams that can be used during an ophthalmic procedure. Accordingly, the surgical laser system <NUM> may be an ophthalmic surgical laser system configured to generate a laser light beam <NUM> (e.g., a surgical treatment beam). A user, such as a surgeon or other medical practitioner, can control the surgical laser system <NUM> (e.g., via a foot switch, voice commands, surgical console, etc.) to fire the laser light beam <NUM> to treat patient anatomy, e.g., perform photocoagulation. In some instances, the surgical laser system <NUM> includes a port, and the illumination beam <NUM> and the laser light beam <NUM> can be emitted through the port in the surgical laser system <NUM>.

System <NUM> can deliver the laser light beam <NUM> and the illumination light <NUM> from the port to a probe <NUM> via a fiber contained in an optical fiber cable <NUM>, a proximal end of which couples to the port of the surgical laser system <NUM> through port adapter <NUM>. As shown, probe <NUM> includes a probe body <NUM>, a probe tip <NUM>, and a distal end <NUM> of the probe tip. In operation, a laser light source of surgical laser system <NUM> generates the laser light beam <NUM>, while an illumination light source generates the illumination light <NUM>. The surgical laser system <NUM> multiplexes the laser light beam <NUM> and the illumination light <NUM> into a multiplexed beam <NUM>. The multiplexed beam <NUM> is directed to a lens of the surgical laser system <NUM> to focus the multiplexed beam onto an interface plane of a proximal end of the fiber within the optical fiber cable <NUM>, such that the multiplexed beam is transmitted along an entire length of the fiber. The interface plane of the proximal end of the fiber is exposed by a ferrule inserted into a port adapter <NUM> through which optical fiber cable <NUM> connects to the surgical laser system <NUM>.

The multiplexed beam <NUM> is transmitted by the fiber to the probe <NUM> disposed at a distal end of the optical fiber cable <NUM>. The multiplexed <NUM> beam exits the probe tip <NUM> and is projected onto the retina <NUM>. Thus, the surgical laser system <NUM> is configured to deliver the multiplexed beam <NUM> to the retina <NUM> through the fiber of the optical fiber cable <NUM>. The multiplexed beam <NUM> includes both the laser light beam <NUM> for the surgical procedure and illumination light <NUM> to aid the user in the procedure, although the beam associated with the laser light beam <NUM> is narrower.

Note that, herein, a distal end of a component refers to the end that is closer to a patient's body, or where the laser light beam <NUM> is emitted out of the laser probe <NUM>. On the other hand, the proximal end of the component refers to the end that is facing away from the patient's body or in proximity to, for example, the surgical laser source <NUM>.

<FIG> illustrates a plan view of a surgical laser system <NUM>, in accordance with certain embodiments of the present disclosure. As shown, the surgical laser system <NUM> includes a first lens <NUM> (e.g., collimating lens), a beam splitter <NUM>, an optical fiber cable <NUM>, a second lens <NUM> (e.g., focusing lens), an illumination light source <NUM>, and a laser light source <NUM>. The beam splitter <NUM> is downstream from the first lens <NUM>, the second lens <NUM> is downstream from the beam splitter <NUM>, and the optical fiber cable <NUM> is downstream from the second lens <NUM>.

The illumination light source <NUM> emits an illumination light <NUM>. The illumination light <NUM> can be any spectrum of light, including, but not limited to, visible light or white light. The illumination light source <NUM> can be a light-emitting diode (LED), a broadband laser, or an incoherent light source such as a xenon or halogen light source. The illumination light <NUM> is collimated by the first lens <NUM> such that the illumination light <NUM> is transformed into a beam of light with parallel rays, as shown. The first lens <NUM> can be any lens, including a plano-convex or biconvex lens. The beam splitter <NUM> allows the illumination light <NUM> to pass through the beam splitter <NUM> with a small fraction of the light reflected off the beam splitter. The illumination light <NUM> is then focused by the second lens <NUM>, as shown. The second lens <NUM> can be any lens used to focus light, including a plano-convex or biconvex lens. The illumination light <NUM> and laser beam <NUM> are focused and incident on the optical fiber cable <NUM> as a multiplexed beam <NUM>, which is described in greater detail below.

The second lens <NUM> focuses the multiplexed beam <NUM> into an interface plane of a proximal end of a fiber that is contained within the optical fiber cable <NUM>. As shown, optical fiber cable <NUM> is coupled to the surgical laser system <NUM> through port adapter <NUM>, which receives a ferrule <NUM> that exposes an interface plane of the proximal end of the fiber, which is contained within optical fiber cable <NUM>. More specifically, the interface plane of the proximal end of the fiber is exposed through an opening <NUM> of ferrule <NUM>. The second lens <NUM> focuses multiplexed beam <NUM> onto an interface plane of the proximal end of the fiber such that the multiplexed beam is propagated through the fiber to the distal end of a surgical probe (e.g., probe <NUM> of <FIG>) that is coupled to cable <NUM>.

The optical fiber cable <NUM> may include a fiber (e.g., fiber <NUM>, a portion <NUM> of which is shown in <FIG>) having a core, an outer cladding, and a coating in some embodiments. In such embodiments, the second lens <NUM> is configured to focus the illumination light <NUM> onto both the core and the outer cladding, in which case both the outer cladding and the core transmit the illumination light <NUM>.

In yet some other embodiments, optical fiber cable <NUM> may include a fiber (e.g., fiber <NUM>, whose portion <NUM> is shown in <FIG>) having a core, an inner cladding, an outer cladding, and a coating. In such embodiments, the illumination light <NUM> is focused on the core, the inner cladding, and the outer cladding in which case the core, the inner cladding, and outer cladding all transmit the illumination light <NUM>.

A laser light source <NUM> emits a laser light beam <NUM>. The laser light beam <NUM> can have any desired wavelength, such as from about <NUM> (nanometers) to about <NUM>. The laser light source <NUM> can emit a variety of wavelengths desired by the user. The laser light beam <NUM> is reflected by the beam splitter <NUM> onto focusing lens <NUM>. The laser light beam <NUM> is then focused by the second lens <NUM> onto an interface plane of the proximal end of optical fiber cable <NUM>, as part of the multiplexed beam <NUM>. The laser light beam <NUM> is transmitted by the core of the optical fiber cable <NUM>. The surgical laser system <NUM> provides both the illumination light <NUM> and the laser light beam <NUM> to the optical fiber cable <NUM> as the multiplexed beam <NUM>. Thus, a single fiber in the optical fiber cable <NUM>, including a core and an outer cladding, is capable of transmitting both the laser light beam <NUM> (through the core) and illumination light <NUM> (through the outer cladding and the core) in the same fiber.

<FIG> illustrates a plan view of the probe <NUM>, in accordance with certain embodiments of the present disclosure. As described above, the probe <NUM> includes a hand piece or probe body <NUM> shaped and sized for grasping by a user. Extending from the probe body <NUM> is the probe tip <NUM> with a distal end <NUM>. The optical fiber cable <NUM> typically comprises a fiber (e.g., fiber <NUM> of <FIG>, fiber <NUM> of <FIG>, etc.) surrounded by a polyvinyl chloride (PVC) tube for protecting the fiber during handling. The fiber extends through the probe body <NUM> and into the probe tip <NUM>. The multiplexed beam <NUM> (shown in <FIG>) emanates from the distal end of the fiber and, thereby, the distal end <NUM> of the probe tip <NUM> onto the retina. In some embodiments, the probe tip <NUM> comprises a first straight portion <NUM> and a second curved portion <NUM>. The first straight portion <NUM> includes a sleeve of the probe tip, and the second curved portion <NUM> includes a tube surrounding the fiber. The embodiment of <FIG> is merely shown as an example. In other examples, a probe tip may include the first straight portion <NUM> and second curved portion <NUM>, but without a sleeve. A variety of other configurations are also possible and are not outside the scope of this disclosure, as one of ordinary skill in the art can appreciate.

<FIG> illustrate a fiber <NUM>, in accordance with certain embodiments of the present disclosure. As shown, the fiber <NUM> includes a core <NUM>, an outer cladding <NUM>, a coating <NUM> (e.g., a low refractive index cladding), and a buffer <NUM>. The buffer <NUM> can include plastic, such as ethylene tetrafluoroethylene (ETFE). The buffer <NUM> is stripped at proximal end <NUM> of the fiber <NUM> so that the proximal end <NUM> of the fiber <NUM> can be inserted to the ferrule. The buffer is also stripped at distal end <NUM> of the fiber <NUM> so that the distal end <NUM> of the fiber <NUM> can be inserted into probe tip <NUM>, according to some embodiments.

<FIG> illustrates a cross-sectional front view of an end face <NUM> of fiber <NUM>, in accordance with certain embodiments of the present disclosure. The end face <NUM> may be a proximal or distal end face of the fiber <NUM>, e.g., located at either proximal end <NUM> or distal end <NUM>. The end face <NUM> includes a core <NUM> disposed in an outer cladding <NUM>, and the outer cladding <NUM> includes a material that can include fused silica. Note, however, that the end face <NUM> does not include the buffer <NUM>, as the buffer <NUM> has been stripped from around the ends <NUM>, <NUM>. Laser light beam <NUM> (shown in <FIG>) provided by a laser light source of the surgical laser system <NUM> is directed into the core <NUM> of the fiber <NUM>. Thus, the core <NUM> conducts the laser light beam <NUM> along the length of the fiber <NUM>. Both core <NUM> and outer cladding <NUM> may include fused silica. However, the core <NUM> is doped with a dopant that increases the index of refraction of the core <NUM>. Therefore, the refractive index of the core <NUM> is greater than the refractive index of the outer cladding <NUM>, such that the laser light beam <NUM> traveling along the core <NUM> is contained within the core <NUM> and prevented from escaping from the core <NUM> into the outer cladding <NUM>. In one example, the dopant can include germanium (Ge). The core <NUM> and the outer cladding <NUM> may both transmit illumination light <NUM> (shown in <FIG>) from the surgical laser system <NUM>. Thus, a single fiber including the core <NUM> and the outer cladding <NUM> is capable of simultaneously transmitting both the laser light beam <NUM> (through the core <NUM>) and illumination light <NUM> (through the outer cladding <NUM> and the core <NUM>). In addition, using fused silica for transmitting the illumination light <NUM>, such as in fiber <NUM> of <FIG> or fiber <NUM> of <FIG>, results in a more thermally stable fiber as compared to a conventional illumination fiber that is made of traditional plastic, and there is no need to use adhesive to bond two fibers, which makes the fiber more thermally robust.

A coating <NUM> is formed over the outer cladding <NUM>. Note that the coating <NUM> may also be referred to as a cladding <NUM>. In some instances, the coating <NUM> is a hard polymer coating. In other instances, the coating <NUM> is formed from other materials, such as acrylate. The refractive index of the coating <NUM> is less than the refractive index of the outer cladding <NUM>, such that the illumination light <NUM> traveling along the outer cladding <NUM> is contained within the outer cladding <NUM> and prevented from escaping from the outer cladding <NUM> into the coating <NUM>. In certain embodiments, the numerical aperture (NA) between the outer cladding <NUM> and the coating <NUM> is greater than about <NUM> to provide the wide illumination required in some surgical cases.

<FIG> illustrates a cross-sectional front view of an end face <NUM> of another fiber <NUM> with an inner cladding <NUM>, in accordance with certain embodiments of the present disclosure. The end face <NUM> may be located at either the proximal end or distal end of the fiber <NUM>, where the fiber's buffer has been stripped. In <FIG>, the inner cladding <NUM> surrounds a core <NUM> and the outer cladding <NUM> surrounds the inner cladding <NUM>. The inner cladding <NUM> can include fused silica doped with dopants, the dopants including fluorine, chlorine, boron, or any combination of the above, according to some embodiments. The dopants change the optical properties of the inner cladding <NUM>, for example, the refractive index. In certain embodiments, the NA between the core <NUM> and the inner cladding <NUM> is from about <NUM> to about <NUM>, such as about <NUM>. The inner cladding <NUM> keeps the laser light beam <NUM> from entering the outer cladding <NUM> by causing partial or total internal reflection of the laser light beam <NUM>, thus keeping the laser light beam <NUM> in the core <NUM>. As described above, in the example of <FIG>, the illumination light <NUM> is focused by the surgical laser system onto core <NUM>, inner cladding <NUM>, and the outer cladding <NUM> while the laser light beam <NUM> is focused on core <NUM>.

Referring to <FIG>, in certain embodiments, the diameter of the cores <NUM>, <NUM> is from about <NUM> to about <NUM>, the outer diameter of the outer cladding <NUM> is from about <NUM> to about <NUM>, and the outer diameter of the coating <NUM> is from about <NUM> to about <NUM>. The location of the centers 302c, 502c of the cores <NUM>, <NUM> is approximately the same location as the center 304c of the outer cladding <NUM>, according to one embodiment.

<FIG> illustrates a partial cross-sectional view of a probe tip <NUM>, in accordance with certain embodiments of the present disclosure. A distal end <NUM> of a fiber, e.g., fiber <NUM>, is partially surrounded by the tube <NUM>, and the tube is surrounded by the sleeve <NUM> of the probe tip <NUM>. The tube <NUM> can include any suitable material, for example, Nitinol, nickel titanium, stainless steel, MP35N (e.g., a nickel-cobalt base alloy), or other alloys. The sleeve <NUM> can include, for example, stainless steel. In the example of <FIG>, the distal end <NUM> of the fiber and the distal end of the tube <NUM> surrounding the fiber extend beyond the distal end of the sleeve <NUM> of the probe tip <NUM>. Thus, the first straight portion <NUM> of the probe tip <NUM> includes the sleeve <NUM>, whereas the second curved portion <NUM> of the probe tip does not include the sleeve, although the distal end <NUM> is still surrounded by the tube <NUM> in the second curved portion. In other embodiments, the sleeve <NUM> extends to cover the entire distal end <NUM> throughout the probe tip <NUM>. In other embodiments, the probe tip <NUM> includes the tube <NUM> and the sleeve <NUM> is not included. Although the distal end <NUM> illustrated in <FIG> includes the inner cladding <NUM>, the optical fiber cable could instead resemble the embodiment in <FIG> (which does not include the inner cladding), without any loss of generality. As described above, the embodiment of <FIG> is merely shown as an example. One of ordinary skill in the art can appreciate other embodiments with different configurations (e.g., a completely straight probe tip, or a probe tip with a distal end that is flush with the distal ends of the fiber <NUM> and tube <NUM>) which are also not outside the scope of this disclosure.

<FIG> illustrates a cross-sectional front view of an end face <NUM> of a fiber, in accordance with certain embodiments of the present disclosure. The end face <NUM> may be a distal and/or proximal end face of the fiber <NUM>, which is partially exposed to an end face roughening treatment to increase an illumination light output angle of the fiber. The end face <NUM>, similar to the end face <NUM> depicted in <FIG>, includes core <NUM> circumferentially surrounded by outer cladding <NUM>, and the outer cladding <NUM> circumferentially surrounded by coating <NUM>. As shown, a surface area of the end face <NUM> corresponding to a cross-section of the outer cladding <NUM> and/or the coating <NUM> is at least partially roughened or coarsened (represented by hatch marks <NUM>), while a surface area of the end face <NUM> corresponding to a cross-section of at least the core <NUM> is substantially smooth. The roughened surface area may be formed during a manufacturing process in which the end face <NUM> is selectively exposed to a particle abrasion treatment, described in more detail below. The particle abrasion treatment creates a surface area with increased light scattering characteristics. The smooth (e.g., flat) surface area, however, is left untreated during the aforementioned manufacturing process to ensure a substantially uniform surface plane, thus maintaining the light transmission properties thereof. In certain embodiments, the smooth or untreated surface area has a diameter that is about the same or slightly larger than a diameter of the core <NUM>.

As described above, laser light, such as laser light beam <NUM>, is propagated within the core <NUM>, while illumination light, such as illumination light beam <NUM>, is propagated within both the core <NUM> and outer cladding <NUM>. Accordingly, by roughening the surface area of the end face <NUM> corresponding to the cross-section of the outer cladding <NUM> and/or the coating <NUM>, the angular spread of the illumination light at the end face <NUM> is increased or widened, thus increasing the overall illumination light output angle of the fiber. In certain embodiments, the illumination light output angle of a fiber having at least one treated end face <NUM> is increased between about <NUM> NA and about <NUM> NA, such as between about <NUM> and about <NUM> NA, as compared to a fiber having both end faces left untreated. Furthermore, by leaving the surface area of the end face <NUM> corresponding to the cross-section of the core <NUM> substantially smooth, laser beam efficiency and spot size of the laser light beam <NUM>, which is propagated only through the core <NUM>, remains unaffected, thus maintaining photocoagulation efficiency while improving the illumination light spreading angle.

<FIG> illustrates a front view of an end face <NUM> of another fiber partially exposed to an end face roughening treatment to improve the illumination light output angle of the fiber, in accordance with certain embodiments of the present disclosure. The end face <NUM> may be a distal or proximal end face of the fiber <NUM>, and includes inner cladding <NUM> circumferentially surrounding core <NUM>, an outer cladding <NUM> circumferentially surrounding the inner cladding <NUM>, and a coating <NUM> circumferentially surrounding the outer cladding <NUM>. As shown, a surface area of the end face <NUM> corresponding to a cross-section of the outer cladding <NUM> and/or the coating <NUM> is exposed to a roughness treatment (represented by hatch marks <NUM>) to increase the illumination light angular spread thereof. The surface area of the end face <NUM> corresponding to a cross-section of at least the core <NUM> and the inner cladding <NUM>, however, is left substantially smooth or untreated to maintain the laser beam efficiency and spot size of the laser light beam <NUM> propagated within the core <NUM>. In certain embodiments, the diameter of the smooth or untreated surface area is substantially the same or larger than a diameter of the inner cladding <NUM>.

In certain embodiments, the roughened surface areas of the end faces <NUM>, <NUM> comprise features having a depth or amplitude between about <NUM> and about <NUM>. In certain embodiments, the roughened surface areas account for at least about <NUM>% of the total surface areas of the end faces <NUM>, <NUM>, such as at least about <NUM>% of the total surface areas, such as at least about <NUM>% of the total surface areas thereof.

For further clarification, <FIG> illustrate schematic cross-sectional views of illumination light and laser light propagating through proximal end faces 911A and distal end faces 911B of several fibers, similar to fibers <NUM> and <NUM> described above. <FIG> illustrates a fiber <NUM> wherein neither the proximal end face 911A nor the distal end face 911B are roughened. As depicted, laser light beam rays 113a enter the core <NUM> at the proximal end face 911A, reflect within the core <NUM> having a minimum angle of incidence L, and exit the core <NUM> at the distal end face 911B with an output angle α relative to a central axis of the fiber. Simultaneously, illumination light rays 150a enter the outer cladding <NUM> at the proximal end face 911A, reflect within the outer cladding <NUM> having a minimum angle of incidence I<NUM>, and exit the outer cladding <NUM> at the distal end face 911B with an output angle φ<NUM> relative to a central axis of the fiber.

<FIG> illustrates a fiber <NUM> wherein a surface area of the proximal end face 911A corresponding to a cross-section of the outer cladding <NUM> is roughened (represented by sawtooth edge <NUM>), causing diffuse scattering (e.g., increased angular spread) of the illumination light rays 150a that pass therethrough and enter the fiber. The diffusely scattered illumination rays 150a have a minimum angle of incidence I<NUM> within the outer cladding <NUM> that is smaller than the angle I<NUM>, and thus exit the outer cladding <NUM> with an output angle φ<NUM> greater than output angle φ<NUM>. The laser light rays 113a entering and propagating through the core <NUM>, however, maintain the minimum angle of incidence L and thus, also maintain the output angle α, resulting in preserved laser beam quality.

<FIG> illustrates a fiber <NUM> wherein a surface area of the distal end face 911B corresponding to a cross-section of the outer cladding <NUM> is roughened (represented by sawtooth edge <NUM>). Accordingly, the illumination light rays 150a reflecting within the outer cladding <NUM> have the same minimum angle of incidence I<NUM> as in <FIG>, but the illumination light rays 150a exit the outer cladding <NUM> at the distal end face 911B with an output angle φ<NUM> greater than output angle φ<NUM> as a result of diffuse scattering caused by the roughened surface. Similar to <FIG>, the laser light rays 113a propagating through the core <NUM> maintain the minimum angle of incidence L and the output angle α, since neither surface area at the distal or proximal end face 911A, 911B corresponding to the core <NUM> is roughened. Accordingly, similar to <FIG>, the angular spread of the illumination light rays 150a at the distal end face 911B of the fiber <NUM> is increased while laser beam spot size and efficiency are preserved.

It should be noted, however, that although only one end face of the fibers in each of <FIG> and <FIG> is roughened, in certain embodiments, both end faces of a fiber may be roughened to achieve a desired illumination light output angle of the fiber. Furthermore, each end face of a fiber may be roughened to a different level or degree of roughness. The difference or delta in level of roughness between end faces may facilitate higher angular spread of illumination light as compared to having a single roughened end face or having two end faces with similar roughness levels. In certain examples, the distal end face is roughened to a greater degree than the proximal end face for higher output angular spread in air and saline mediums as compared to only roughening the distal end face, while also maintaining illumination light throughput similar to roughening of only the proximal end face.

<FIG> illustrates a flow diagram of a method <NUM> for treating an end face of a fiber to increase an illumination light output angle thereof, in accordance with certain embodiments of the present disclosure. <FIG> schematically illustrate front views of an end face <NUM> of a fiber at different stages of the method <NUM> represented in <FIG>. Therefore, <FIG> and <FIG>-11C are herein described together for clarity.

The method <NUM> may be utilized to form the end faces <NUM>, <NUM> described above. In certain embodiments, only one of the distal or proximal end faces of the fiber is treated according to the methods described herein. In certain other embodiments, both of the distal and proximal end faces of the fiber are treated. Generally, the method <NUM> begins at operation <NUM> and <FIG>, wherein a mask <NUM> is applied to a surface area of the end face <NUM> corresponding to a cross-section of at least a core (core <NUM> is shown in <FIG>), and in certain embodiments, an inner cladding (e.g., inner cladding <NUM>) of the fiber. For example, the mask <NUM> may have a diameter that is substantially the same or larger than a diameter of the core <NUM> or the inner cladding <NUM>. In certain embodiments, the mask <NUM> comprises an adhesive, such as a UV-adhesive or epoxy, that is cured upon application to the end face <NUM> by exposing the mask <NUM> to UV light. Prior to application of the mask <NUM>, the end face <NUM> may be flat polished to facilitate better adhesion of the mask <NUM> and/or form a more specular surface for optimal propagation of the laser light beam <NUM> to or from the core <NUM>.

At operation <NUM> and <FIG>, the masked end face <NUM> is exposed to a particle abrasion process, such as a sand-blasting process utilizing aluminum oxide (AlO<NUM>) particles having diameters of between about <NUM> and about <NUM>, such as about <NUM>. As a result, an exposed surface area of the end face <NUM>, e.g., the surface area of the end face <NUM> corresponding to the cross-section of the outer cladding (e.g., outer cladding <NUM>) and coating (e.g., coating <NUM>) of the fiber is at least partially roughened or coarsened by the particle abrasion process (represented as hatch marks <NUM> in <FIG>), while the surface area protected by the mask <NUM>, e.g., the surface area corresponding to the cross-section of the core of the fiber, is unaffected. The amount of illumination light scattering caused by the end face <NUM> is correlated to the level or degree of roughness thereof. Thus, increasing the time of exposure to the particle abrasion process or increasing the velocity of the particles abrading the end face <NUM> may increase the amount of illumination light scattering caused by end face <NUM>. As previously described, in embodiments where both distal and proximal end faces of the fiber are treated, the degree of roughness may be varied for each of the proximal and distal end. For example, the proximal end may be roughened relatively lightly while the distal end is roughened relatively heavily, or vice-versa. The difference in level of roughness between end faces may facilitate higher angular spread of illumination light as compared to having a single roughened end face or having two end faces with similar roughness levels.

After the particle abrasion process, the mask <NUM> is removed and the end face <NUM> is cleaned at operation <NUM> and <FIG>. For example, the end face <NUM> is exposed to an ultrasonic cleaning process utilizing an alcohol solution to remove the mask <NUM> and clean the end face <NUM>. The resulting end face <NUM> includes a substantially planar surface area corresponding to the cross-section of at least the core of the fiber, and a roughened surface area (represented as hatch marks <NUM> in <FIG>) corresponding to the cross-section of at least the outer cladding.

As noted earlier, the end faces of a fiber may be treated at least one of two ways to increase the illumination output angle of an optical fiber cable. In addition to being exposed to a roughening process as described with reference to <FIG>, one or more end faces of the fiber may be angled or beveled by a polishing process to increase the illumination light scattering characteristics of the optical fiber.

<FIG> illustrate a perspective view and a partial cross-sectional view, respectively, of a beveled end <NUM> of a fiber having a substantially frustoconical end face <NUM>, in accordance with certain embodiments of the present disclosure. The end <NUM> may be a distal or proximal end of the fiber <NUM>, which is exposed to an angled polishing process to increase an illumination light output angle of the fiber. The end <NUM>, similar to the portion <NUM> depicted in <FIG>, includes core <NUM> circumferentially surrounded by outer cladding <NUM>, and the outer cladding <NUM> is circumferentially surrounded by coating <NUM>. A surface area <NUM> of the end face <NUM> corresponding to a cross-section of at least the core <NUM> is planar and substantially orthogonal relative to a central axis <NUM> of the end <NUM>. In certain embodiments, the planar surface area <NUM> of the end <NUM> corresponds to an entire cross-section of the core <NUM>, as well as a portion of a cross-section of the outer cladding <NUM>. For example, the planar surface area <NUM> of the end <NUM> may have a diameter substantially the same or greater than a diameter of the core <NUM>, such as a diameter between about <NUM>% and about <NUM>% greater than a diameter of the core <NUM>.

A surface area <NUM> of the end face <NUM> corresponding to a cross-section of the outer cladding <NUM>, on the other hand, is angled relative to the planar surface area <NUM>. The angled surface area <NUM> is disposed at an angle Θ relative to the planar surface area <NUM>. In certain embodiments, the angle Θ is between about <NUM>° and about <NUM>° relative to the planar surface area <NUM>. In certain other embodiments, the angle Θ is between about <NUM>° and about <NUM>° relative to the planar surface area <NUM>. Other angles are also contemplated (e.g., the angle Θ may be between about <NUM>° and about <NUM>° relative to the surface area <NUM>). Together, the planar surface area <NUM> and the angled surface area <NUM> form the frustoconical shape of the end face <NUM>.

The beveled structure of the end <NUM> functions similarly to the roughened surface areas described above with reference to <FIG> and increases the illumination light output angle of the fiber. As described above, laser light, such as laser light beam <NUM>, is transmitted into or out of the core <NUM> through planar surface area <NUM> of the end face <NUM>, thus remaining unaffected by the beveled structure of the end <NUM>. Illumination light, such as illumination light beam <NUM>, however, is transmitted into or out of both the core <NUM> and outer cladding <NUM>. Illumination light passing through the outer cladding <NUM> is thus refracted by the angled surface area <NUM>, which increases the angular spread of the illumination light at end face <NUM> as compared to a planar end face surface. The increased angular spread of the illumination light at end face <NUM> results in an overall increased illumination light output angle of the fiber. Accordingly, the illumination light output angle of the fiber can be modulated by increasing or decreasing the angle of surface area <NUM> relative to surface area <NUM>, all the while preserving laser beam quality. In certain embodiments, the illumination light output angle of a fiber having at least one beveled end <NUM> is increased between about <NUM> NA and about <NUM> NA, such as between about <NUM> and about <NUM> NA, as compared to a fiber having two planar (e.g., completely flat) end faces.

<FIG> illustrates a partial cross-sectional view of another beveled end <NUM> of a fiber having an angled end face <NUM> to increase an illumination output angle of the fiber, in accordance with certain embodiments of the present disclosure. The end face <NUM> may be a distal or proximal end face of the fiber <NUM> depicted in <FIG>, and includes inner cladding <NUM> circumferentially surrounding core <NUM>, outer cladding <NUM> circumferentially surrounding the inner cladding <NUM>, and coating <NUM> circumferentially surrounding the outer cladding <NUM>. A surface area <NUM> of the end face <NUM> corresponding to a cross-section of at least the core <NUM> and the inner cladding <NUM> is planar and substantially orthogonal relative to a central axis <NUM> of the end <NUM>. In certain embodiments, the planar surface area <NUM> of the end <NUM> corresponds to an entire cross-section of the core <NUM> and the inner cladding <NUM>, as well as a portion of a cross-section of the outer cladding <NUM>. For example, the planar surface area <NUM> may have a diameter substantially the same or greater than a diameter of the inner cladding <NUM>, such as a diameter between about <NUM>% and about <NUM>% greater than a diameter of the inner cladding <NUM>.

A surface area <NUM> of the end face <NUM> corresponding to a cross-section of the outer cladding <NUM> and/or the coating <NUM> is disposed at angle Θ relative to the surface area <NUM>. In certain embodiments, the angle Θ is between about <NUM>° and about <NUM>° relative to the surface area <NUM>. In certain other embodiments, the angle Θ is between about <NUM>° and about <NUM>° relative to the surface area <NUM>. Other angles are also contemplated (e.g., the angle Θ may be between about <NUM>° and about <NUM>° relative to the surface area <NUM>). The angle of the surface area <NUM> functions to modulate the angular spread of illumination light <NUM> passing therethrough.

Although depicted as specular surfaces in <FIG>, in certain embodiments, the angled surface areas <NUM> and <NUM> are roughened (e.g., using the techniques described above) to further increase the angular spread of illumination light <NUM> passing therethrough. In certain embodiments, the angled surface areas <NUM> and <NUM> are non-linear in truncation (e.g., a cross-section of the beveled end faces <NUM> and <NUM> includes non-linear edges for surfaces areas <NUM> and <NUM>). For example, in certain embodiments, the angled surface areas <NUM>, <NUM> are wavy or undulating in morphology for greater angular spread of illumination light <NUM> passing therethrough.

<FIG> illustrates a flow diagram of a method <NUM> for polishing an end of a fiber to form a beveled end face and increase an illumination light output angle thereof, in accordance with certain embodiments of the present disclosure. <FIG> schematically illustrate cross-sectional views of an end <NUM> of a fiber at different stages of the method <NUM> represented in <FIG>. Therefore, <FIG> and <FIG>-15C are herein described together for clarity.

The method <NUM> may be utilized to form the ends <NUM> and <NUM> having end faces <NUM>, <NUM> described above. In certain embodiments, only one of the distal or proximal end faces of the fiber is polished according to the methods described herein. In certain other embodiments, both of the distal and proximal end faces of the fiber are polished. Generally, the method <NUM> begins at operation <NUM> and <FIG>, wherein a jacket <NUM>, such as buffer <NUM>, is stripped from the fiber (end <NUM> of the fiber is shown in <FIG>). In certain examples, the jacket <NUM> is formed of plastic, such as ETFE.

At operation <NUM> and <FIG>, the end <NUM> is polished along a circumferential edge of end face <NUM> to form an angled surface area <NUM>. The polishing process at operation <NUM> is performed at one or more desired angles to form the angled surface area <NUM> having at least an angle Θ relative to a planar top surface area <NUM>. Together, the planar surface area <NUM> and the angled surface area <NUM> may form the beveled shape of the end face <NUM>. In certain embodiments, the polishing process is performed at multiple desired angles to form an angled surface area <NUM> having a nonlinear taper, as described above. Increasing the nonlinearity of the angled surface area <NUM> may increase the amount of illumination light scattering caused thereby, and thus, the degree of angular spread at end face <NUM> may be modulated by modifying the linearity (e.g., number of angles relative to the surface area <NUM>) of the surface area <NUM>.

In some examples, the angled surface area <NUM> is polished to have an angle Θ between about <NUM>° and about <NUM>° relative to the planar surface area <NUM>. In some examples, the angled surface area <NUM> is polished to have an angle Θ between about <NUM>° and about <NUM>° relative to the planar surface area <NUM>. Other angles are also contemplated (e.g., the angle Θ may be between about <NUM>° and about <NUM>° relative to the planar surface area <NUM>). In embodiments where both distal and proximal ends of the fiber are beveled, the number and degree of angles may be varied for each of the proximal and distal ends. The differences in beveling between ends may facilitate even higher angular spread of illumination light emitted by the fiber.

Upon formation of the angled surface area <NUM>, the planar surface area <NUM> of the end <NUM> is polished and cleaned using a flat polishing process at operation <NUM> and <FIG>. The flat polishing process ensures specularity of the planar surface area <NUM>, and further ensures the planar surface area <NUM> encompasses at least an entire cross-section of the core <NUM>, thus preserving quality of the laser light beam <NUM> emitted therefrom. Generally, the polishing processes at operation <NUM> may be performed utilizing the same polishing system as used for operation <NUM>, such as a mechanical fiber polisher having a polishing platen or plate. The resulting end face <NUM> includes a substantially planar surface area <NUM> corresponding to the cross-section of at least the core <NUM> of the fiber, and an angled surface area <NUM> corresponding to the cross-section of at least the outer cladding <NUM>.

As described above, an optical fiber cable is capable of transmitting both a laser light beam through a core, and illumination light through the core and an outer cladding. The optical fiber cable does not have two separate fibers for illumination light and the laser light beam, but rather one fiber that includes a core to transmit the laser light beam, and the core and an outer cladding to transmit the illumination light. The optical fiber cable can be used in a system for medical procedures, and the system provides both laser light beam for the cauterizing or burning, and illumination light to aid the user in performance of the procedure.

The use of a combined core and outer cladding to transmit both the laser light beam and illumination light results in a more compact fiber, and removes the need for adhering two fibers together. The narrower fiber is useful for medical procedures that require thinner probe tips. In addition, the optical fiber cable is more thermally stable than a traditional optical fiber cable, due to the lack of thermally unstable adhesive. The use of a single fiber in the optical fiber cable removes the need for two connectors (one for each fiber), and thus only one connector is necessary, which reduces the manufacturing and labor costs, as there is no need to handle assembly of two fibers.

Furthermore, treating surface areas corresponding to the outer cladding on one or both end faces of the fiber enables a compact fiber having a large illumination output angle while maintaining laser beam performance of the fiber. One or both end faces of the fiber are treated by a roughening or polishing process to form a roughened or angled surface around the core. The roughened or angled surfaces increase the angular spread of illumination light transmitted therethrough without affecting transmission of the laser light beam to or from the core, thus causing the increased illumination output angle of the fiber without impairing laser efficiency. Accordingly, the single compact fiber may be utilized for medical procedures requiring larger illumination spreading angles.

Claim 1:
A fiber (<NUM>, <NUM>, <NUM>), comprising:
a proximal end face (<NUM>, <NUM>, <NUM>, <NUM>) at a proximal end of the fiber (<NUM>, <NUM>);
a distal end face (<NUM>, <NUM>, <NUM><NUM>) at a distal end of the fiber (<NUM>, <NUM>);
a core (<NUM>, <NUM>) configured to transmit a laser light beam and an illumination light;
an outer cladding (<NUM>) circumferentially surrounding the core and configured to transmit the illumination light, wherein at least a surface area of the proximal end face or the distal end face corresponding to the outer cladding is roughened; and
a coating (<NUM>) circumferentially surrounding the outer cladding.