Patent Publication Number: US-2012027417-A1

Title: Optical power divider

Description:
BACKGROUND 
     Fiber optic transmission of data offers many advantages over more traditional forms of data transmission between electronic devices. For instance, optical signals are generally immune to errors caused by electromagnetic interference, and systems utilizing the optical signals are typically less prone to sparking and short circuiting. The use of fiber optic transmission also eliminates ground loop problems by providing electrical isolation between optically linked equipment. 
     Fiber optic transmission systems is often employed in distributed processing systems, such as, in a local area network, in a data bus system, between various servers, and the like. These systems typically require the use of processors or terminals to communicate data with each other as well as with other peripheral devices. In this regard, conventional fiber optic transmission systems often use a ring or a star type architecture to enable the data communication among a plurality of electronic devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments are illustrated by way of example and not limited in the following figure(s), in which like numerals indicate like elements, in which: 
         FIG. 1  depicts a perspective view of a data communication system including an optical power divider, according to an embodiment of the invention; 
         FIG. 2  shows a schematic diagram of a data communication system, according to an embodiment of the invention; and 
         FIG. 3  shows a schematic diagram of a data communication system, according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     For simplicity and illustrative purposes, the principles of the embodiments are described by referring mainly to examples thereof. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent however, to one of ordinary skill in the art, that the embodiments may be practiced without limitation to these specific details. In other instances, well known methods and structures are not described in detail so as not to unnecessarily obscure the description of the embodiments. 
     Disclosed herein are embodiments directed to an optical power divider and a fiber optic communication system that employs the optical power divider. The optical power divider disclosed herein comprises cylindrical input lenses that receive input light beams and expand the light beams along respective single axes through the optical power divider. Here the term ‘cylindrical’ lens refers to any curved surface that varies along one direction only; for example the cross-section could be circular or hyperbolic. In this regard, the received input light is spread along one axis according to the divergence angle of the source of the light beams, without substantially spreading along other axes, which substantially maximizes the intensities of the light beams. The optical power divider disclosed herein also includes output lenses that vary along two axes, for instance, the output lenses may have spherical or aspheric surfaces and may be positioned along the respective axes of light beam expansion, in which the output lenses are configured to focus the expanded light beams into multiple beams of output light. 
     A relatively large number of output lenses may be provided on the optical power divider to thus enable the input light beams to be split into a relatively large number of output beams. For instance, a sufficient number of output lenses may be provided to extend across most of the width of an optical power divider such that greater than 90% of the input light is outputted through the output lenses. In this regard, most of the received light may be passed through the optical power divider, which results in substantially maximized output light beam strengths. 
     The optical power divider disclosed herein may be fabricated from a single plastic component into which the cylindrical input lenses and the spherical or aspheric output lenses are formed. Thus, for instance, the optical power dividers disclosed herein may be formed through a relatively simple and inexpensive molding process. 
     The optical power divider disclosed herein may be employed in a fiber optic data communication system through which data is communicated among a plurality of electronic devices. In one example, the optical power divider may be operated as a star coupler between a plurality of the electronic devices. 
     In the following description, the term “light” refers to electromagnetic radiation with wavelengths in the visible and non-visible portions of the electromagnetic spectrum, including infrared and ultra-violet portions of the electromagnetic spectrum. 
     With reference first to  FIG. 1 , there is shown a perspective view of a data communication system  100  including an optical power divider  102 , according to an embodiment of the present invention. It should be understood that the data communication system  100  depicted in  FIG. 1  may include additional components and that some of the features described herein may be removed and/or modified without departing from a scope of the data communication system  100 . 
     As depicted in  FIG. 1 , the data communication system  100  includes an optical power divider  102 , a plurality of light beam sources  140 , and a plurality of light beam collectors  150 . The optical power divider  102  is depicted as being positioned between the light beam sources  140  and the light beam collectors  150 . In addition, the optical power divider  102  is depicted as receiving input light beams  142  from the light beam sources  140  and outputting a larger number of output light beams  146  to the light beam collectors  150 . In  FIG. 1 , a single output light beam  146  has been depicted and identified for purposes of clarity. 
     The optical power divider  102  is depicted as having a generally rectangular or square shaped, three-dimensional body  110 . It should, however, be clearly understood that the body  110  may have any other suitable three dimensional shape. In any regard, the optical power divider  102  is depicted as including a first side  120  that faces toward the light sources  140  and a second side  130  that faces toward the light beam collectors  150 . The first side  120  has also been depicted as including a plurality of cylindrical input lenses  122  that extend across a width of the first side  120 , along a y-axis. The cylindrical input lenses  122  have also been depicted as being spaced apart from each other along the z-axis to receive input light beams  142  from respective light beam sources  140 . The second side  130  includes a plurality of spherical or aspheric output lenses  132  that are positioned across the width of the second side  130 , along the y-axis. 
     As further shown in  FIG. 1 , the cylindrical input lenses  122  are configured to expand the input light beams  142  along a first axis, in this case, the y-axis. The expanded light beams  144  are depicted as the dashed lines extending through the body  110  between the cylindrical input lenses  122  and the spherical/aspheric output lenses  132 . More particularly, each of the cylindrical input lenses  122  collimates a respective input light beam  142  with respect to the z-axis, but allows the input light beam  142  to expand across a relatively wide area along a single axis (y-axis) to be directed to a respective group of the spherical or aspheric output lenses  132 . The group of the output lenses  132  for a particular cylindrical input lens  122  comprises those output lenses  132  that are arranged along the single axis along which the cylindrical input lens  122  allows the light beams  144  to expand. Thus, in the example depicted in  FIG. 1 , the uppermost group of spherical/aspheric output lenses  132  that extend along the y-axis receive light that has been allowed to expand by the uppermost cylindrical input lens  122 , and so forth. 
     The expansion of the input light beams  142  may be restricted to a single axis to substantially maximize the intensities of the light beams emitted and expanded through the body  110  of the optical power divider  102 . In one possible configuration, each of the cylindrical lenses  122  may have a hyperbolic cross section designed such that light originating from a particular point at the light beam source ( 140 ) will be perfectly collimated with respect to the z-axis. In addition, the second side  130  of the body  110  may include groups of spherical or aspheric output lenses  132  that extend substantially across the width of the body  110  to substantially maximize the number of output light beams  146  originating from each of the cylindrical input lenses  122 . Thus, although the output lenses  132  in each group have been depicted as being relatively spaced apart from each other, it should be clearly understood that the output lenses  132  may be positioned to be substantially adjacent to each other and to substantially fill the space along the y-axis of the second side  130 , for instance, as shown in  FIG. 3 . 
     In addition, the boundaries of the output lenses  132  need not be circular as depicted in the  FIG. 1 , but rather, may be rectangular or square, such that the output lenses  132  cover substantially all of the illuminated surface area of the second side  130 . Moreover, the output lenses  132  may be substantially evenly spaced along the y axis, or the output lenses  132  may be unevenly spaced to substantially equalize the total power sent to each light beam collector  150 , taking into account the distribution of ray angles produced by a particular light beam source  140 . Furthermore, the curved surfaces of the output lenses  132  may be aspheric and may thus be designed such that light originating from a single point at the source  140  is imaged as perfectly as possible to a set of points at the light beam collectors  150 . The aspheric surface may be defined by a mathematical function f(y,z) that has different curvatures with respect to y and z in order to achieve a substantially optimized focus onto the light beam collectors  150 . By using aspheric surfaces, acceptable imaging performance may be achieved in a relatively compact device. In addition, the aspheric surfaces may be formed in a relatively easy manner onto the second side  130  without requiring relatively expensive manufacturing costs, for instance, when the optical power divider  102  is molded from plastic. 
     In one example, the cylindrical input lenses  122  and the spherical or aspheric output lenses  132  are configured to cause substantially all of the input light beams  142 , except for light emerging from the light beam sources  140  at too steep of an angle to reach the output lenses  132 , to reach the light beam collectors  150 . 
     The body  110  of the optical power divider  102  is formed of a transparent material to substantially minimize intensity loss of the light beams through the body  110 . By way of example, the body  110  comprises a plastic material, a glass material, a combination of plastic and glass materials, and the like. In one embodiment, the body  110  is molded to include the cylindrical input lenses  122  and the spherical/aspheric output lenses  132 . In another embodiment, the cylindrical input lenses  122  and the spherical/aspheric output lenses  132  are formed on the body  110  by, for instance, diamond turning, etching, carving, milling, photolithography, melting and reflow, etc. 
     The light beam sources  140  may comprise any suitable devices through which light beams may be supplied to the optical power divider  102 . By way of example, the light beam sources  140  comprise multimode fibers, single-mode fibers, vertical-cavity surface-emitting lasers, hollow waveguides, optical waveguides, etc. In addition, the light beam collectors  150  may comprise any suitable devices through which light beams may be collected and transmitted. By way of example, the light beam collectors  150  comprise multimode fibers, optical waveguides, etc. 
     Although not shown, the positions of the light beam sources  140  and the light beam collectors  150  may be substantially maintained with respect to the optical power divider  102  in any suitable manner that does not interfere with the transmission of the input light beams  142  or the output light beams  146 . Thus, for instance, the positions of the light beam sources  140  and the light beam collectors  150  may substantially be maintained through use of mechanical components, such as, brackets, or other components. As another example, the light beam sources  140  and the light beam collectors  150  may be attached to the optical power divider  102  through use of adhesives. 
     With reference now to  FIG. 2 , there is shown a schematic diagram of a data communication system  200  and a cross-sectional side view of the optical power divider  102 , according to an example of the invention. It should be understood that the data communication system  200  depicted in  FIG. 2  may include additional components and that some of the features described herein may be removed and/or modified without departing from a scope of the data communication system  200 . 
     The data communication system  200  depicted in  FIG. 2  includes all of the same features as the data communication system  100  depicted in  FIG. 1 .  FIG. 2  differs from  FIG. 1 , however, in that a cross-sectional top view of the optical power divider  102  is depicted in  FIG. 2 . In addition, an electronic device A has been depicted as being connected to the light beam source  140  and a plurality of electronic devices B-D  204 - 208  have been depicted as being connected to respective ones of the light beam collectors  150 . Although not shown, additional electronic devices may be positioned beneath the electronic device  202  along the z-axis to provide input light beams  142  into the optical power divider  102 . 
     As shown in  FIG. 2 , the data communication system  200  enables data to be communicated from the electronic device A  202  to the other electronic devices B-D  204 - 208 . More particularly, the optical power divider  102  enables data to be simultaneously broadcasted to each of the electronic devices B-D  204 - 208 . The optical power divider  102  may thus operate as a star coupler. The electronic devices B-D  204 - 208  may also be configured to communicate data to other ones of the electronic devices  202 - 208  through other similar optical power dividers  110 . In any regard, the electronic devices A-D  202 - 208  may comprise any of a plurality of different types of electronic devices configured to communicate and receive data through optical signals. For instance, the electronic device  202 - 208  may comprise servers, CPUs, circuit boards, etc. 
     As shown in  FIG. 2 , an input light beam  142  is generated by the electronic device  202  and is inputted into the cylindrical input lens  122  through the light beam source  140 . The cylindrical input lens  122  expands the input light beam  142 , such that the expanded light beam  144  is expanded to illuminate a plurality of spherical or aspheric output lenses  132 . In addition, the spherical output lenses  132  that receive the expanded light beam  144  focus the received light into respective output beams of light  146 , which are directed to respective light beam collectors  150 . The output light beams are transmitted through the light beam collectors  150  to respective electronic devices B-D  204 - 208 . In this regard, data from the electronic device A  202  may be communicated to each of the other electronic devices A-D  204 - 208  through transmission of optical signals through the optical power divider  102 . 
     Turning now to  FIG. 3 , there is shown a schematic diagram of a data communication system  300  and a cross-sectional side view of the optical power divider  102 , according to another example of the invention. It should be understood that the data communication system  300  depicted in  FIG. 3  may include additional components and that some of the features described herein may be removed and/or modified without departing from a scope of the data communication system  300 . 
     The data communication system  300  depicted in  FIG. 3  includes all of the same features as the data communication system  200  depicted in  FIG. 2 , except for the configuration of the spherical/aspheric output lens  132  of the optical power divider  102  and the addition of another electronic device  210 . As shown in  FIG. 3 , the second side  130  is depicted as including a plurality of spherical/aspheric output lenses  302 . The spherical/aspheric output lenses  302  differ from the spherical/aspheric output lenses  132  depicted in  FIGS. 1 and 2  in that the spherical/aspheric output lenses  302  are configured to cause a greater amount of light in the body  110  to be outputted to the electronic devices  204 - 210 . In this regard, the spherical/aspheric output lenses  132  are arranged along the second side  130  with respect to each other to substantially reduce or eliminate gaps between the spherical/aspheric lenses  132 . As such, the spherical/aspheric output lenses  132  are substantially adjacent to each other when viewed along a side view of the optical power divider  102 . 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. The foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive of or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations are possible in view of the above teachings. The embodiments are shown and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents: