Abstract:
An optical fiber tip attachment comprising:
       a body having an opening at a first end of the body, the opening configured to receive an optical fiber; and   a cavity extending from the opening through at least a portion of the body, wherein the cavity is configured to orient a cross-sectional surface of the optical fiber, from which electromagnetic radiation is delivered, at an angle to an axis of the optical fiber tip attachment at the opening.

Description:
RELATED APPLICATIONS 
     This Application is a continuation application of U.S. application Ser. No. 14/411,656, filed Dec. 29, 2014, now U.S. Pat. No. 9,304,260, granted on Apr. 5, 2016, which is a 371 national phase application of PCT/IB2013/055402, filed Jul. 1, 2013, which claims priority to U.S. Provisional Patent Application No. 61/667,025, filed Jul. 2, 2012. 
    
    
     BACKGROUND 
     Lasers are used in a variety of medical procedures, such as treatment of kidney stones and benign prostatic hyperplasia, for example. In some such medical procedures it is advantageous to utilize an optical fiber that delivers the laser or electromagnetic radiation at an angle rather than along the axis of the optical fiber. Such fibers are commonly referred to as side-firing lasers. Typical side-firing lasers use reflection, such as internal reflection, to direct the laser at an angle. 
     SUMMARY 
     According to a first aspect of the invention there is provided an optical fiber tip attachment comprising a body having an opening at a first end of the body, the opening configured to receive an optical fiber; and a cavity extending from the opening through at least a portion of the body, wherein the cavity is configured to orient a cross-sectional surface of the optical fiber, from which electromagnetic radiation is delivered, at an angle to an axis of the optical fiber tip attachment at the opening 
     The optical fiber tip attachment may comprise a second opening, the cavity extending from the first opening to the second opening. 
     The cavity may be configured to orient a cross-sectional surface of the optical fiber at an angle to an axis that is perpendicular to a plane through the opening in the body. 
     The optical fiber tip attachment may further comprise a top located at a second end of the body. 
     The cavity may extend through a portion of the body and a portion of the top. 
     The cavity may extend only through the body. 
     The top may have a hemispherical shape. 
     The top and body may be formed from a single continuous material. 
     The top may be formed as a separate element from the body, the top being attached to the second end of the body. 
     The top may include at least one extension configured to be coupled to an inner surface of the body. 
     The cavity may have an approximately uniform width. 
     The cavity may comprised of a chamber and a channel, wherein the chamber is wider than the channel. 
     Where the optical fiber tip attachment comprises a top, the chamber may extend through the body and the channel may extend through the top. 
     Where the optical fiber tip attachment comprises a second opening, the chamber may be proximate the first opening and the channel may be proximate the second opening. 
     The cavity may be configured to orient the optical fiber such that the cross-sectional surface of the optical fiber is not perpendicular to an axis of the optical fiber when the optical fiber is cut to be approximately flush with an outer surface of the optical fiber tip attachment. 
     The cavity may be curved to orient the optical fiber. 
     An outer surface of the body and top may be curved, the curvature of the outer surface of the body and top corresponding to the curvature of the cavity. 
     The optical fiber tip attachment may be divided along a longitudinal axis into a first segment and a second segment, wherein the first segment may comprises a first half of the body and a first half of the cavity; and wherein the second segment may comprise a second half of the body and a second half of the cavity, the first and second segments being configured to be coupled together to secure the optical fiber in the cavity. 
     Where the optical fiber tip attachment comprises a top, the first segment may comprise a first half of the top and the second segment may comprise a second half of the top 
     According to a second aspect of the invention there is provided an optical fiber assembly comprising an optical fiber having a bulbous portion at a first end of the optical fiber; and an optical fiber tip attachment according to the first aspect of the invention having a first end and a second end, the optical fiber tip attachment surrounding a segment of the optical fiber proximate the bulbous portion, the first end of the optical fiber tip attachment coupled to the bulbous portion, wherein the optical fiber tip attachment is configured to bend the segment of the optical fiber surrounded by the optical fiber tip attachment. 
     The optical fiber tip attachment may be further configured to maintain an air gap between a cylindrical surface of the segment of the optical fiber surrounded by the optical fiber tip attachment and an inner surface of the optical fiber tip attachment. 
     An outer surface and an inner surface of the optical fiber tip attachment may be curved longitudinally. 
     According to a third aspect of the invention there is provided a laser system comprising an optical fiber, a laser energy source configured to provide electromagnetic radiation to a first end of the optical fiber, and an optical fiber tip attachment coupled to a second end of the optical fiber, the optical fiber tip attachment comprising an optical fiber tip attachment according to the first aspect of the invention. 
    
    
     
       DRAWINGS 
       Understanding that the drawings depict only exemplary embodiments and are not therefore to be considered limiting in scope, the exemplary embodiments will be described with additional specificity and detail through the use of the accompanying drawings, in which: 
         FIG. 1  is a high level block diagram of one embodiment of an exemplary laser system. 
         FIG. 2  is a cross-sectional view of one embodiment of an exemplary fiber tip attachment. 
         FIG. 3  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 4  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 5A  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 5B  is a front view of the exemplary fiber tip attachment of  FIG. 5A . 
         FIG. 6  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 7  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 8  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 9  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 10  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 11  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 12  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
         FIG. 13  is a cross-sectional view of another embodiment of an exemplary fiber tip attachment. 
     
    
    
     In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the exemplary embodiments. 
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific illustrative embodiments. However, it is to be understood that other embodiments may be utilized and that logical, mechanical, and electrical changes may be made. The following detailed description is, therefore, not to be taken in a limiting sense. 
       FIG. 1  is a high level block diagram of one embodiment of an exemplary laser system  100 . System  100  includes a laser energy source  102  configured to provide electromagnetic radiation to an optical fiber  104 . The optical fiber  104  has a first end  101  coupled to the optical fiber  104  for receiving the electromagnetic radiation generated by the laser energy source  102  and a second end  103  from which the electromagnetic radiation is delivered to a target. For example, the system  100  can be used in performing medical procedures that involve delivery of electromagnetic radiation to tissue, such as, but not limited to, medical procedures for treating benign prostatic hyperplasia (BPH). 
     The optical fiber  104  is comprised of a fiber core, cladding, and buffer or coating, as known to one of skill in the art. In a section  106  at the second end  103  of the optical fiber  104 , the optical fiber  104  extends beyond an outer jacket or sheath  116  as shown in  FIG. 1 . In addition, a rigid fiber tip  108  (also referred to herein as a fiber tip or fiber tip attachment) is placed over the optical fiber  104  in section  106 . The rigid fiber tip  108  is configured to cause the optical fiber to bend such that the electromagnetic radiation is delivered at an angle  110  from an axis  112  that is perpendicular to a cross-sectional surface of the outer jacket  116  as described in more detail below with respect to  FIG. 2 . 
     In particular,  FIG. 2  depicts one exemplary embodiment of a fiber tip  208  for an optical fiber  204 . As shown in  FIG. 2 , the orientation of the cross-sectional surface  214  of the outer jacket  216  is depicted by axis  213  which is perpendicular to the plane  215  that extends through the cross-sectional surface  214 . Similarly, the orientation of a cross-sectional surface  218  of the optical fiber  204  is depicted by axis  211  which is perpendicular to the plane  217  that extends through the cross-sectional surface  218 . The cross-sectional surface  218  is also referred to herein as an emission surface because the electromagnetic radiation is emitted through surface  218 . 
     The body  220  and top  222  of the fiber tip  208  are comprised of a rigid material such as, but not limited to, metals, metal alloys, or rigid polymers. The body  220  is an elongated portion of the fiber tip  208  and the top  222  is a rounded portion at the end of the fiber tip  208 . The fiber tip  208  includes a cavity  221  that extends from a first opening  250  in the fiber tip  208  to a second opening  252  in the fiber tip  208 . In this embodiment, the cavity  221  extends through both the body  220  and top  222 . It is to be understood that although the orientation of the surface  218  is described in relation to the orientation of the cross-sectional surface  214 , the orientation of the surface  218  can also be described in relation to an orientation of the first opening  250 . That is, the fiber tip  208  is configured to orient the surface  218  at an angle to an axis  254  that is perpendicular to a plane  256  through the first opening. 
     In addition, in this example, the cavity  221  includes a channel  226  formed through the top  222  and a chamber  224  formed through the body  220 . The chamber  224  is placed over the exposed portion of the optical fiber  204  and a portion of the outer jacket  216 . The body  220  is angled such that it contacts the outer jacket  216  to hold the fiber tip  208  in place. 
     As shown in  FIG. 2 , the width of the channel  226  is narrower than the width of the chamber  224 . In particular, the width of the channel  226  is approximately equal to, but larger than, the diameter of the optical fiber  204  such that the optical fiber  204  is maintained inside the channel  226  through friction. Thus, a force can be applied to the optical fiber  204  to push the end of the optical fiber  204  beyond an outer surface  228  of the top  222 . The optical fiber  204  can then be cut or cleaved such that the cross-sectional surface  218  is approximately flush with the outer surface  228 . By enabling the cutting of the optical fiber  204 , the fiber tip  208  enables damaged or degraded fiber at the end of the optical fiber to be removed and the remaining portion of the optical fiber  204  to continue to be used. 
     In addition, in the example of  FIG. 2 , the channel  226  is located approximately in the center of the top  222 . However, since the body  220  is bent, the orientation of the cross-sectional surface  218  of the optical fiber  204  is displaced at an angle  210  from the orientation of the cross-sectional surface  214  of the outer jacket  216 . The angle  210  is determined and configured based on the intended application or use of the optical fiber  204 . For example, the rigid fiber tip  208  can be configured, in some embodiments, to displace the optical fiber  204  at an angle selected from the range of 75° to 90°. 
     Although the top  222  has a hemispherical shape in the example of  FIG. 2 , it is to be understood that other shapes can be used in other embodiments. For example, in  FIG. 3 , the top  322  has an elongated irregular shape approximately in the form of a semi-elliptical shape. Also, the channel  326  in  FIG. 3  is located off-center. That is, the channel  326  is not located in approximately the center of the top  322 . Furthermore, as shown in  FIG. 3 , due to the shape of the top  322  and the location of the channel  326 , the surface  318  of the optical fiber  304  is not perpendicular to the fiber axis  319  when cut to be approximately flush with the outer surface  328  of the top  322 . The axis  319  is a longitudinal axis of the fiber  304  at the second opening The angled surface  318 , thus, influences the direction of electromagnetic radiation that is delivered from the tip of the optical fiber  304 . Therefore, the shape of the top  322  and location of the channel  326  can be configured to determine the angle at which the electromagnetic radiation is delivered. 
       FIG. 4  depicts a cross-sectional view of another embodiment of an exemplary rigid fiber tip  408 . Similar to fiber tip  208 , fiber tip  408  includes a cavity  421  including a chamber  424 , defined by body  420  and top  422 , and a channel  426  in the top  422 . In addition, fiber tip  408  depicts an alternative technique for attaching the fiber tip  408  to the optical fiber  404  and outer jacket  416 . In particular, the fiber tip  408  is inserted into and attaches to a rigid sheath  409  having dimensions that enable the sheath  409  to fit over and attach to the outer jacket  416  rather than using the configuration of the body  420  to hold the fiber tip  408  in place. 
     Furthermore, it is to be understood that in other embodiments, the fiber tip is configured differently. For example, the exemplary fiber tip  508  shown in  FIGS. 5A and 5B  does not curve as in the exemplary fiber tips discussed above. 
     Additionally, as shown in the cross-section side view in  FIG. 5A , the cavity  520  of fiber tip  508  does not include a hollow chamber and a channel Rather, the cavity  521  has a substantial uniform width as it extends through the fiber tip  508 . A fiber optic cable  504  is placed in the cavity  521 . In particular, as shown in  FIG. 5B , the fiber tip  508  is comprised of two corresponding sections  501 - 1  and  501 - 2 . Each section contains a cavity  521  which matches the cavity  521  in the other section. After placing a fiber optic cable  504  into the cavity  521  of one of the sections  501 , the two sections  501 - 1  and  501 - 2  are coupled together, such as with screws  530 . Once coupled together, the sections  501 - 1  and  501 - 2  form the complete cavity  521 . The size of the cavity  521  is approximately equal to, but larger than, the diameter of the optical fiber  504  such that the optical fiber  504  is maintained in place in the cavity  521  via the force of friction. Also, since the cavity  521  maintains the optical fiber  504  in position, the fiber tip  508  does not need to be directly attached to the outer jacket  516 , as shown in  FIG. 5 . 
     In addition, although the fiber tip  508  is not curved, the cavity  521  is curved such that the emission surface  518  of the fiber  504  is oriented at an angle to the axis  554  which is perpendicular to a plane  556  through the opening  550  of the fiber tip  508 . Similar to the exemplary fiber tip shown in  FIG. 3 , the location and orientation of the cavity  521  in the fiber tip  508  causes the optical fiber to be cut an angle  532  that is not perpendicular to the axis  519  of the optical fiber  504  at the second opening  552  when the fiber  504  is cut to be approximately flush with an outer surface  528  of the fiber tip  508 . 
     Other configurations of the fiber tip are also implemented in other embodiments. For example,  FIGS. 6-8  depict exemplary configurations of the body, top, and cavity of a fiber tip. In particular, in  FIG. 6 , the body  620  and top  622  are not formed integrally as one continuous material. Rather the top  622  is a separate element that is coupled to the body  620 . In addition, the top  622  is shaped as a hollow hemisphere with the channel  624  formed through the top  622  at an angle to the longitudinal axis  634  of the fiber tip  608 . 
     In  FIG. 7 , the top  722  and the body  720  are also separate elements as in the example of  FIG. 6 . However, the top  722  is a hemispherical shape with extensions  735 . The extensions  735  support the attachment of the top  722  to the body  720 . In the example of  FIG. 8 , the top  822  is also hemispherical in shape. However, in the example of  FIG. 8 , the channel  824  of the cavity  821  is formed in the body  820  rather than the top  822 . 
       FIGS. 9-11  depict other exemplary configurations of the fiber tip. In particular, in the examples shown in  FIGS. 9-11 , the body and top are formed integrally as one continuous material. As shown in  FIGS. 9-11 , the respective fiber tips  908 ,  1008 , and  1108  vary in shape from one another. For example, the top  1022  of fiber tip  1008  is more spherical than the top  922  or  1122 , whereas, the shape of fiber tip  1108  mirrors more closely the path of the channel  1126 . In addition, the fiber tip does not have to be made of straight segments which are bent at an angle. Indeed, the outer surface and inner surface of the exemplary fiber tips in  FIGS. 9-11  are gradually curved longitudinally. That is, the fiber tips curve along the length of the fiber tip. Hence, it is to be understood that the shape of the fiber tip, as well as the placement of the channel can change depending on the specific implementation. 
     For example, the shape of the fiber tip can be configured for optical fibers having irregular shapes, such as the optical fiber  1204  in  FIG. 12 . The optical fiber  1204  includes a bulbous portion  1238  at the end of the optical fiber  1204 . The fiber tip  1208  attaches to the base of the bulbous portion  1238  via an adhesive, for example. In addition, the fiber tip  1208  is rigid and provides a gap  1242  between the optical fiber  1204  and an inner surface  1240  of the fiber tip  1208 . The gap  1242  helps prevent leakage of the electromagnetic radiation from the optical fiber  1204  into the surrounding environment, such as tissue. The rigid fiber tip  1208  is also bent to cause the optical fiber  1204  to bend as described above. Fiber tip  1308  is similar to fiber tip  1208 . However, rather than being bent at an angle like fiber tip  1208 , the fiber tip  1308  is curved longitudinally. 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiments shown. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.