Abstract:
A flexible waveguide with an adjustable index of refraction. The core layer and/or the cladding layer of a flexible waveguide may include a plurality of nanoparticles having a different index of refraction than the core layer and/or cladding layer. The plurality of nanoparticles may have an index of refraction that is greater than or less than an index of refraction of either the core layer or the cladding layer in order that the overall effective index of refraction of either the core layer or the cladding layer can be adjusted.

Description:
BACKGROUND 
     A flexible waveguide is an optical component that can provide for directing or guiding an electromagnetic wave in a generally non-linear direction. Data storage systems often incorporate optical components to assist in the recording of information. Such systems may include, for example, optical recording systems, magneto-optical recording systems or other thermal assisted type recording systems. There is an increased emphasis on improving the areal densities of data storage systems. Thus, all components of data storage systems are being improved and new components are being incorporated into data storage systems to achieve higher areal densities. 
     SUMMARY 
     An aspect of the present invention is to provide a flexible waveguide having a core layer and a plurality of nanoparticles contained in the core layer. The core layer has a core material with a first index of refraction. Each of the nanoparticles has a second index of refraction that is greater than the first index of refraction of the core material. 
     Another aspect of the present invention is to provide an apparatus including a core layer structured and arranged to direct an electromagnetic wave in a generally nonlinear direction and a plurality of nanoparticles contained in the core layer. The core layer has a core material with a first index of refraction. Each of the nanoparticles has a second index of refraction that is different than the first index of refraction of the core material. The first index of refraction may be less than the second index of refraction, or the first index of refraction may be greater than the second index of refraction. 
     A further aspect of the present invention is to provide an apparatus including a cladding layer generally disposed about a core layer and a plurality of nanoparticles contained in the cladding layer. The cladding layer has a cladding material with a first index of refraction. Each of the nanoparticles has a second index of refraction that is different than the first index of refraction of the cladding material. The first index of refraction may be less than the second index of refraction, or the first index of refraction may be greater than the second index of refraction. 
     An additional aspect of the present invention is to provide a data storage system including means for storing data, means for reading and/or writing data in association with the means for storing data, and a flexible waveguide for directing an electromagnetic wave to the means for reading and/or writing data. The flexible waveguide includes a core layer and means for adjusting the effective index of refraction of the core layer. 
     These and various other features and advantages will be apparent from a reading of the following detailed description. 
    
    
     
       DRAWINGS 
         FIG. 1  is a pictorial representation of a system, in accordance with an aspect of the invention. 
         FIG. 2  is a plan view of an actuator arm, in accordance with an aspect of the invention. 
         FIG. 3  is partial side schematic view of  FIG. 2 , in accordance with an aspect of the invention. 
         FIG. 4  is a schematic cross-sectional view taken along line  4 - 4  of  FIG. 3 . 
         FIG. 5  is a schematic cross-sectional view taken along line  5 - 5  of  FIG. 4 . 
         FIG. 6  is a schematic cross-sectional view taken along line  6 - 6  of  FIG. 4 . 
         FIG. 7  is a graphical illustration of effective index of refraction. 
         FIG. 8  is a graphical illustration of effective index of refraction. 
         FIG. 9  is a partial schematic representation of a slider with a flexible waveguide and an additional waveguide, in accordance with an aspect of the invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a pictorial representation of a system  10  that can include aspects of this invention. The system  10  includes a housing  12  (with the upper portion removed and the lower portion visible in this view) sized and configured to contain the various components of the system  10 . The system  10  includes a spindle motor  14  for rotating at least one disc  16  within the housing  12 . At least one actuator arm  18  is contained within the housing  12 , with each arm  18  having a first end  20  with a slider  22 , and a second end  24  pivotally mounted on a shaft by a bearing  26 . An actuator motor  28  is located at the arm&#39;s second end  24  for pivoting the arm  18  to position the slider  22  over a desired sector  27  of the disc  16 . The actuator motor  28  is regulated by a controller, which is not shown in this view and is well known in the art. 
       FIG. 2  is a plan view of an actuator arm  118  having a laser module  132  mounted thereon, in accordance with an aspect of the invention. The laser module  132  directs an electromagnetic wave  133  to a flexible waveguide  140 . An optical component such as, for example, a lens  134 , may be positioned between the laser module  132  and the waveguide  140  to focus the wave  133 . The flexible waveguide  140  is used to conduct the electromagnetic wave  133  from the laser module  132  to a slider  122 . From the flexible waveguide  140 , the electromagnetic wave  133  can be coupled into a waveguide on the slider  122  and directed onto an adjacent data storage medium (see  FIG. 9 ). 
       FIG. 3  is partial side schematic view of  FIG. 2  with the actuator arm  118  not shown for simplification of illustration.  FIG. 3  illustrates that at least a portion of the flexible waveguide  140  is non-linear for conducting the electromagnetic wave  133  therethrough in a generally non-linear direction. Specifically, a portion  142  of the flexible waveguide  140  between a first end  144  and a second end  146  of the flexible waveguide  140  can have a curvature for conducting the electromagnetic wave  133  therethrough in a generally non-linear direction. It will be appreciated that the flexible waveguide  140  can have various portions thereof capable of non-linear conduction of the wave  133 . 
       FIG. 4  is a schematic cross-sectional view taken along line  4 - 4  of  FIG. 3 . As shown, the flexible waveguide  140  has a core layer  148  and a cladding layer  150  disposed at least partially about the core layer  148 . 
       FIG. 5  is a schematic cross-sectional view taken along line  5 - 5  of  FIG. 4 . Specifically, the core layer  148  includes a core material  152  and a plurality of nanoparticles  154  dispersed throughout the core material  152 . The core material  152  has an index of refraction that may be in the range of about 1.2 to about 1.8. The core material  152  may be formed of, for example, polymethylmethacrylate, polystyrene, polycarbonate, or silicone polymers such as polysiloxanes or siloxanes. Each nanoparticle  154  may have an index of refraction that is in the range of about 1.5 to about 3.5. The nanoparticles  154  may be formed of at least one of diamond like carbon, Ta 2 O 5 , TiO 2 , SiN, HfO 2 , ZrO 2 , AlN or Al 2 O 3 . In accordance with an aspect of the invention, the index of refraction of the nanoparticles  154  is greater than the index of refraction of the core material  152 . By dispersing the nanoparticles  154  in the core material  152 , the overall effective index of refraction of the core layer  148  can be increased. For example, the overall effective index of refraction of the core layer  148  may be in the range of about 1.2 to about 3.5. However, it will be appreciated that in accordance with an aspect of the invention nanoparticles having an index of refraction that is less than an index of refraction of a core layer material may be dispersed in the core layer material to decrease the overall effective index of refraction of the core layer. 
     The core layer  148  may, for example, have a thickness T 1  in the range of about 100 nm to about 1 mm. In one aspect, the nanoparticles  154  may each have a diameter that is less than about 80 nm. In another aspect, the nanoparticles  154  may each have a diameter that is less than about one-tenth of the wavelength of the electromagnetic wave  133  that will propagate through the flexible waveguide  140 . 
       FIG. 6  is a schematic cross-sectional view taken along line  6 - 6  of  FIG. 4 . Specifically,  FIG. 6  shows the cladding layer  150  that is formed of a cladding material  156  and a plurality of nanoparticles  158  that are dispersed in the cladding material  156 . The cladding material  156  may be, for example, polymethylmethacrylate, polystyrene, polycarbonate, or silicone polymers such as polysiloxanes or siloxanes. The cladding material  156  may have an index of refraction in the range of about 1.2 to about 1.8. The plurality of nanoparticles  158  may be each formed of, for example, diamond like carbon, Ta 2 O 5 , TiO 2 , SiN, HfO 2 , ZrO 2 , AlN or Al 2 O 3 . Each nanoparticle  158  may have an index of refraction in the range of about 1.5 to about 3.5. 
     In one aspect of the invention, the index of refraction of each nanoparticle  158  is greater than the index of refraction of the cladding material  156 . This provides for dispersing the nanoparticles  158  in the cladding material  156  so as to increase the overall effective index of refraction of the cladding layer  150 . For example, the effective index of refraction of the cladding layer  150  may be in the range of about 1.2 to about 3.5. However, it will be appreciated that in accordance with an aspect of the invention nanoparticles having an index of refraction that is less than an index of refraction of a cladding layer material may be dispersed in the cladding layer material to decrease the overall effective index of refraction of the cladding layer. 
       FIG. 7  graphically illustrates the effective index of refraction for a cladding layer, such as cladding layer  150 , versus the index of refraction of nanoparticles, such as nanoparticles  158 , that are dispersed in a cladding material, such as cladding material  156 , having an index of refraction of about 1.60 for a corresponding fill factor that represents the percentage of particles contained within the cladding material. For example, for a cladding material having the index of refraction of about 1.60 with a 25% fill factor of nanoparticles having an index of refraction of 2.2, the effective index of refraction would be about 1.70 to about 1.75 (see the point labeled with reference number  162  in  FIG. 7 ). 
       FIG. 8  shows a graphical illustration similar to  FIG. 7 , but for a core layer such as, for example, core layer  148 , having a core material such as, for example, core material  152 , with an index of refraction of about 1.62. 
       FIG. 9  is a partial schematic representation of the slider  122  with the flexible waveguide  140 , and particularly the second end  146  thereof, positioned adjacent to a surface of the slider  122 . The slider  122  further includes an additional waveguide, generally represented by reference number  170 , adjacent another surface of the slider  122 . The waveguide  170  may be used, for example, in association with a data storage device for generating an optical spot  172  on the surface of a data storage media  116 . Such arrangements are useful, for example, in a thermal assisted or heat assisted data storage system. The waveguide  170  includes a core layer  174  and a cladding layer  176  disposed thereabout. A turning mirror  178  may be provided for reflecting the electromagnetic wave  132  that is being transmitted through the core layer  148  of the flexible waveguide  140  such that the electromagnetic wave  132  is coupled into the core layer  174  of the planar waveguide  170 . In accordance with an aspect of the invention, the ability to increase or decrease the index of refraction for a waveguide, such as, for example, the flexible waveguide  140 , results in the ability to better match the mode index with another waveguide, such as, for example, planar waveguide  170 , so as to have increased coupling efficiency therebetween. 
     The implementation described above and other implementations are within the scope of the following claims.