Patent Publication Number: US-11656423-B2

Title: Colored ribbon with discrete color layers

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/806,278, filed Mar. 2, 2020, which claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/825,389 filed on Mar. 28, 2019, the content of each of which is relied upon and incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     The disclosure relates generally to optical fibers, and specifically to optical fiber ribbons having an opacifying and/or color layer with exposed indicator fibers. A single optical fiber cable may contain many optical fibers (indeed, hundreds of optical fibers), and during installation of a fiber optic cable network, managing the connections between the optical fibers can be difficult. Thus, various portions of the optical fiber cable, such as individual optical fibers, buffer tubes, or ribbons, may be color coded for the purposes of identification when making such connections. 
     SUMMARY 
     Embodiments of the disclosure relate to an optical fiber ribbon. The optical fiber ribbon includes a plurality of optical fibers arranged in a row having a first width. A first indicator fiber is provided at a first edge of the row, and a second indicator fiber is provided at a second edge of the row. The first indicator fiber has a first fiber jacket of a different color than a second fiber jacket of the second indicator fiber. The optical fiber ribbon also includes a primary matrix into which the plurality of optical fibers are embedded. The primary matrix has an outer surface. The optical fiber ribbon also includes an opacifying layer having a second width and being composed of a first base resin and an opacifier. The optical fiber ribbon also includes a color layer distinct from the opacifying layer. The color layer has a third width and includes a second base resin and a colorant. The colorant is different from the opacifier. The optical fiber ribbon further includes a layer of printing disposed on the outer surface of the primary matrix. In the optical fiber ribbon, the first width is greater than at least one of the second width or the third width such that the first indicator fiber and the second indicator fiber each extend past at least one of the opacifying layer or the color layer. 
     Additional embodiments of the disclosure relate to an optical fiber ribbon. The optical fiber ribbon includes a plurality of optical fibers arranged in a row having a first width. The plurality of optical fibers includes a first indicator fiber provided at a first edge of the row, a second indicator fiber provided at a second edge of the row, and at least a first interior fiber disposed between the first indicator fiber and the second indicator fiber. The first indicator fiber has a first fiber jacket of a different color than a second fiber jacket of the second indicator fiber. The optical fiber ribbon also includes a primary matrix into which the plurality of optical fibers are embedded. The primary matrix has an outer surface. The optical fiber ribbon includes a first color layer having a first base resin and a first colorant. The first color layer defines a first continuous coating over at least the first interior fiber. The optical fiber also includes a layer of printing disposed on the outer surface of the primary matrix. Further, the optical fiber includes a secondary matrix surrounding the primary matrix such that the layer of printing is disposed between the primary matrix and the secondary matrix. 
     Further embodiments of the disclosure relate to a method of preparing an optical fiber ribbon. In the method, a plurality of optical fibers are arranged in a row. The plurality of optical fibers includes a first indicator fiber at a first end of the row, a second indicator ribbon at a second end of the row, and at least one interior fiber disposed between the first indicator fiber and the second indicator fiber. In a first applicator, the at least one interior fiber is coated with an opacifying layer comprising a first base resin and an opacifier. A primary matrix is applied around the plurality of optical fibers in the first applicator during the step of coating. Information regarding characteristics of the optical fiber ribbon is printed onto the primary matrix, and a secondary matrix is applied around the primary matrix in a second applicator such that the printed information is disposed between the primary matrix and the secondary matrix. 
     Still further, embodiments of the disclosure relate to a method of preparing an optical fiber ribbon. In the method, a plurality of optical fibers is arranged in a row. The plurality of optical fibers includes a first indicator fiber at a first end of the row, a second indicator ribbon at a second end of the row, and at least a first interior fiber disposed in the row between the first indicator fiber and the second indicator fiber. In a first applicator, the first interior fiber is coated with a first color layer made up of a first base resin and a first colorant. A primary matrix is applied around the plurality of optical fibers in the first applicator during the step of coating. Information regarding characteristics of the optical fiber ribbon is printed onto the primary matrix. Further, a secondary matrix is applied around the primary matrix in a second applicator such that the printed information is disposed between the primary matrix and the secondary matrix. 
     Additional features and advantages will be set forth in the detailed description that follows, and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings. 
     It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims. 
     The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and the operation of the various embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a plan view of a portion of an optical fiber ribbon, according to an exemplary embodiment; 
         FIG.  2    is a cross-sectional view of the optical fiber ribbon taken along line  2 - 2  of  FIG.  1   , according to an exemplary embodiment; 
         FIG.  3    is an enlarged view of a portion of the cross-section of  FIG.  2   , according to an exemplary embodiment; 
         FIG.  4    schematically depicts a partial cross-sectional view of an optical fiber ribbon, according to another exemplary embodiment; 
         FIG.  5    schematically depicts a partial cross-sectional view of an optical fiber ribbon, according to a further exemplary embodiment; 
         FIG.  6    schematically depicts a partial cross-sectional view of an optical fiber ribbon, according to yet another exemplary embodiment; 
         FIG.  7    schematically depicts a partial cross-sectional view of an optical fiber ribbon, according to still further exemplary embodiment; 
         FIG.  8    schematically depicts a partial cross-sectional view, according to yet another exemplary embodiment; 
         FIG.  9    schematically depicts a partial cross-sectional view, according to an additional exemplary embodiment; 
         FIG.  10    is a schematic representation of a processing line for preparation of the various embodiments of the optical fiber ribbon, according to an exemplary embodiment; 
         FIG.  11    depicts a schematic representation of a coating applicator, according to an exemplary embodiment; and 
         FIG.  12    is a photograph of a cross-sectional view of an optical fiber ribbon, showing the various coating layers, according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring generally to the figures, various embodiments of an optical fiber ribbon having exposed indicator fibers are provided. That is, in an optical fiber ribbon, the optical fibers between the two outside optical fibers (i.e., the “interior fibers”) are partially or totally obscured by an opacifying layer and/or a color layer. Because the indicator fibers at the edge are not obscured or at least not obscured to the level of the interior optical fibers, a technician can discern the polarity (direction that light signals travel through an optical fiber) of the optical fiber based on the observable color-coded order of the optical fibers in the ribbon. The interior optical fibers are obscured using at least one of an opacifying layer or a color layer. The optical fibers are also embedded in a primary matrix and a secondary matrix with a printed layer therebetween. The printed layer provides another means of identification in addition to the indicator fibers. Advantageously, the opacifying layer and the color layer can be applied at the same time as the primary matrix and/or the secondary matrix using the same applicator. 
     As described herein, embodiments of the optical fiber ribbon have an opacifying layer applied over the optical fibers or over a primary matrix into which the optical fibers are embedded. Thereafter, printing is applied to the outside of the primary matrix, and a secondary matrix is applied over the printing to protect it from smudging. In embodiments, the secondary matrix acts as the color layer. In other embodiments, the color layer is applied over the fibers or over the opacifying layer. In still further embodiments, both an opacifying layer and a color layer are applied to one or both sides of the optical fibers, and the primary and secondary matrices are applied around the optical fibers with the printing contained therebetween. In still another embodiment, two or more color layers are applied to the optical fibers with an overlap region between at least two of the color layers. In this way, a first color region is provided over certain optical fibers, a second color region is provided over other optical fibers, and a third color region is provided in the overlap region over still other optical fibers. Each of these exemplary embodiments will be described in greater detail below, and these exemplary embodiments are provided by way of illustration, and not by way of limitation. These and other aspects and advantages will be discussed in relation to the embodiments provided below. 
       FIG.  1    depicts an exemplary embodiment of an optical fiber ribbon  10  according to the disclosure. The optical fiber ribbon  10  includes a plurality of optical fibers  12  arranged in a substantially planar row. The number of optical fibers  12  contained in the row varies by embodiment. In embodiments, the number of optical fibers  12  in a row is from four to thirty-six. Further, in embodiments, the optical fibers  12  may be divided into subunits  15  of from two to twelve optical fibers  12 . In the embodiment shown in  FIG.  1   , the optical fiber ribbon  10  includes a single subunit  15  of twelve optical fibers  12 . In the optical fiber ribbon  10 , the optical fibers  12  are coated with an opacifying layer  14  and a color layer  16 . As will be described more fully below, the optical fiber ribbon  10  has indicator fibers  12   a  (generally, at least the optical fibers  12  located at the edges of the row of optical fibers  12 ) that are used to provide a reference polarity. In order to provide reference polarity, the indicator fibers  12   a  are left at least partially uncovered by at least one of the opacifying layer  14  and the color layer  16 . That is, the optical fibers  12  between the indicator fibers  12   a  (referred to as “interior fibers”  12   b  as shown in  FIG.  3   ), are more obscured than the indicator fibers  12   a , allowing the indicator fibers  12   a  to more readily stand out visibly on the optical fiber ribbon  10 . 
     As can also be seen in  FIG.  1   , the optical fiber ribbon  10  includes a printing layer  18 , which is made up of ink dots  20 . The ink dots  20  may be used to provide identifying characteristics of the optical fiber ribbon  10  in the printing  18  layer. 
     As shown in  FIG.  2   , a primary matrix  22  holds the plurality of optical fibers  12  such that they are substantially parallel, adjacent, and are disposed, at least at a given cross section of the optical fiber ribbon  10 , in substantially the same planar row. In embodiments, the longitudinal axis of each optical fiber  12  is substantially parallel to and coplanar with its adjacent optical fiber  12 . The primary matrix  22  is coated with a secondary matrix  24 . As can be seen in the embodiment of  FIG.  2   , the optical fiber ribbon  10  has a “dog-bone” structure in which the primary matrix  22  is thicker at the end regions. In these regions, the thickness of the secondary matrix  24  may reduce to approximately 0 μm. In the embodiment depicted, the printing layer  18  is contained between the primary matrix  22  and the secondary matrix  24 . As mentioned briefly above, by placing the printing layer  18  between the primary matrix  22  and the secondary matrix  24 , the printing layer  18  is advantageously protected from accidental removal or abrasion, especially during installation, thereby preserving the legibility of the printing layer  18 . 
     In embodiments, the optical fibers  12  embedded in the primary matrix  22  are color coded as shown by the color abbreviations in  FIG.  2   . For example, the optical fibers  12  going from left to right are color coded as follows: BL—blue; OR—orange; GR—green; BR—brown; SL—slate; WH—white; RD—red; BK—black; YL—yellow; VI—violet; RS—rose; and AQ—aqua. In embodiments containing more than twelve optical fibers  12 , the pattern of colors may be repeated. The optical fibers  12  are color coded in this way to help organize and identify specific fibers  12  when making connections or splices. Further, as mentioned above, the indicator fibers  12   a  are less obscured by the opacifying layer  14  and/or color layer  16  than the interior fibers  12   b . In this way, a technician can use the color coding of the optical fibers  12  to determine polarity of the optical fiber ribbon  10  based on the indicator fibers  12   b.    
     The color of the optical fibers  12  can make reading the printing layer  18  between the primary matrix  22  and the secondary matrix  24  difficult. In particular, the darker colored fibers  12  tend to limit the contrast between the ink of the printing layer  18  and the background. Thus, the opacifying layer  14  (or, in embodiments, the color layer  16 ) creates a contrasting background for the printing layer  18 . In a particular embodiment, the opacifying layer  14  includes a pigment, ink, dye, or other colorant as an opacifier. In embodiments, the pigment provides the opacifying layer  14  with a color of white, gray, or black. 
     In terms of the CIE L*c*h* color space, using a white opacifier causes the lightness (L*) values for all of the optical fibers  12  to increase, which makes the color whiter, and the saturation (chroma—c*) decreases, which decreases the intensity of the colors. The hue angle h* for the colors remains the same. By increasing lightness and decreasing chroma, the optical fibers  12  become less visible through the opacifying layer  14 . In this way, the printing layer  18  is able to contrast more with the underlying opacifying layer  14 . In some embodiments, the color layer  16  is provided below the printing layer  18 . In such embodiments, the color layer  16  may contain an opacifier to enhance contrast. 
     As can be seen in  FIGS.  1  and  2   , the printing layer  18  is comprised of a plurality of dots  20  of ink. In embodiments, the ink dots  20  are printed using inkjet printing on the opacifying layer  14  or primary matrix  22 . In embodiments, the ink dots  20  are substantially circular and have a diameter of from 200 μm to 350 μm. In embodiments, the dots have a thickness of 2 μm to 10 μm. In embodiments, the color of the ink dots  20  is selected to provide good contrast with the color of the opacifying layer  14 . For example, when the opacifying layer  14  is white, the ink dots  20  may be selected to be black. An example of a black ink suitable for use for the ink dots  20  is MB175 (available from Markem-Imaje, Switzerland). In another example, when the opacifying layer  14  is black or gray, the ink dots  20  may be selected to be yellow. An example of a yellow ink suitable for use for the ink dots  20  is Yellow MC258 (available from Markem-Imaje, Switzerland). Other color combinations between the ink dots  20  and the opacifying layer  14  are possible, and these examples are provided by way of illustration only and not by way of limitation. 
       FIG.  3    provides an enlarged view of a portion of the optical fiber  10 . In  FIG.  3   , the structure of the optical fibers  12  is depicted. The optical fibers  12  are comprised of a core  26  surrounded by a cladding  28 . Optical signals are carried by the core  26 , and the cladding  28  substantially prevents the optical signals from escaping the core  26  during transmission. In embodiments, the cladding  28  is coated with a primary coating  30  that is made of a relatively softer, cushioning material. The primary coating  30  is further coated with a secondary coating  32  that is made of a harder material to provide abrasion resistance. Disposed outside of the secondary coating  32  is a fiber jacket  34  that comprises, e.g., a dye, an ink, or a pigment that provides one of the color-coded identifying colors discussed above for the fiber  12 . 
     As can be seen in  FIG.  3   , the primary matrix  22  is provided above and below the optical fibers  12  as well as in the spaces between optical fibers  12  (although, in practice, the primary matrix  22  may not entirely fill the space between optical fibers  12  and air gaps may be present between adjacent optical fibers  12 ). In embodiments, the optical fibers  12  are embedded in the primary matrix  22 , which forms a continuous and contiguous layer of polymer material around the optical fibers  12 . In various embodiments, substantially all of the outer surface of the fiber jacket  34  contacts the primary matrix  22 . In the embodiment depicted in  FIG.  3   , the opacifying layer  14  is coated over the primary matrix  22  and is embedded in the secondary matrix  24 , which serves as the color layer  16 . 
       FIG.  3    depicts a midline  40  of the cross-section of the optical fiber ribbon  10 . The midline  40  divides the optical fiber ribbon  10  into a first portion  42  and a second portion  44 . With respect to the orientation of the  FIG.  3   , the first portion  42  is shown as the upper portion of the optical fiber ribbon  10 , and the second portion  44  is shown as the lower portion of the optical fiber ribbon  10 . In the embodiment of  FIG.  3   , the opacifying layer  14  is located only in the first portion  42 , but in other embodiments, the opacifying layer  14  may additionally or alternatively be located in the second portion  44 . 
     In embodiments, the average thickness T 1  of the secondary matrix  24  is from 10 μm to 35 μm. The average thickness T 2  of the opacifying layer  14  is from 20% to 100% of T 1 , or from 2 μm to 35 μm. As mentioned above, the average thickness T 3  of the ink dots  20  is from 2 μm to 10 μm. As described, opacifying layer  14  is able to obscure a portion of the color of the fiber jacket  34  so as to provide a contrasting background for the ink dots  20  of the printing layer  18 . Further, the color layer  16 , which is incorporated in the secondary matrix  24 , provides identification of the optical fiber ribbon  10 . In the embodiment depicted, the primary matrix  22  is uncolored and unopacified. 
     As discussed above, the indicator fibers  12   a  are left at least partially uncovered by the opacifying layer  14 . In embodiments, each optical fiber  12  has a diameter D, and the optical fibers  12  are arranged in a planar row and in an edge-to-edge fashion such that the number N of optical fibers  12  defines a width of approximately D*N (with some small gaps potentially existing between adjacent optical fibers  12 ). In each of the embodiments described here, at least one of the opacifying layer  14  or the color layer  16  has a width that is less than the width of the planar row of optical fibers  12 . In this way, the indicator fibers  12   a  will extend (at least partially) past one or both of the opacifying layer  14  and the color layer  16 . In this way, the interior fibers  12   b  will be obscured by both the opacifying layer  14  and the color layer  16 , whereas the indicator fibers  12   a  will have at least a region that is only obscured by at most one of the opacifying layer  14  or the color layer  16 . 
     With respect to the embodiment shown in  FIG.  3   , the color layer  16  is incorporated into the secondary matrix  24 , and thus, the color layer  16  has a width wider than the width of the planar row of optical fibers  12 . As can be seen, though, the opacifying layer  14  has a width that is less than width of the planar row of optical fibers  12 . In embodiments, the width of the opacifying layer  14  is selected to be at least about D(N−2). In such embodiments, the opacifying layer  14  may be substantially centered over the interior fibers  12   b  such that equal amounts (about an entire diameter D) of the indicator fibers  12   a  at the edge of the row are exposed. In other embodiments, the width of the opacifying layer  14  is selected to be no more than D(N−0.5). In such embodiments, the opacifying layer  14  may be centered over the interior fibers  12   b  such that about 0.25 D of each indicator fiber  12   a  at the edge of the row is exposed. In the other embodiments described below, either one or both of the opacifying layer  14  or the color layer  16  may, in embodiments, have a width of from D(N−2) to D(N−0.5). 
       FIG.  4    depicts another embodiment of an optical fiber ribbon  10  that is substantially similar to the embodiment shown in  FIG.  3    with the exception that, in the embodiment of  FIG.  4   , the opacifying layer  14  is coated onto the optical fibers  12  instead of the primary matrix  22 . As shown in  FIG.  4   , the opacifying layer  14  is coated onto the interior fibers  12   b  and is located in the first portion  42  above the midline  40 . However, in other embodiments, the opacifying layer  14  may be located additionally or alternatively in the second portion  44  below the midline  40 . In embodiments, the opacifying layer  14  has an average thickness T 4  proximal to the midline  40  (i.e., in the region between adjacent optical fibers  12 ) of 5 μm to 50 μm and an average thickness T 5  over the remainder of the optical fibers  12  of from 5 μm to 50 μm. 
     In the embodiment of  FIG.  4   , the primary matrix  22  is provided around the optical fibers  12  and the opacifying layer  14 . That is, the optical fibers  12  and opacifying layer  14  are embedded in the primary matrix  22 , which forms a continuous and contiguous layer of polymer material around the optical fibers  12  and the opacifying layer  14 . As with the previous embodiment, the printing layer  18  is applied in ink dots  20  over the primary matrix  22 , and the secondary matrix  24 , which incorporates the color layer  16 , is applied around the printing  18  and primary matrix  22 . In the embodiment depicted, the primary matrix  22  is uncolored and unopacified. 
       FIG.  5    depicts another embodiment of an optical fiber ribbon  10  having just a color layer  16 . In this embodiment, the color layer  16  is coated onto the interior fibers  12   b , leaving the indicator fibers  12   b  at the edge of the row exposed. In the embodiment shown in  FIG.  5   , the color layer  16  is located in the first portion  42  above the midline  40 . However, in other embodiments, the color layer  16  may be located additionally or alternatively in the second portion  44  below the midline  40 . The color layer  16  has an average thickness T 4  proximal to the midline  40  in the space between the optical fibers  12  of from 5 μm to 50 μm and an average thickness T 5  over the remainder of each optical fiber  12  of from 5 μm to 50 μm. In embodiments, an opacifier may be incorporated into the color layer  16 . That is, the color layer  16  can contain both a colorant and an opacifier, which is applied over the interior fibers  12   b.    
     In the embodiment of  FIG.  5   , the primary matrix  22  is provided around the optical fibers  12  and the color layer  16 . That is, the optical fibers  12  and color layer  16  are embedded in the primary matrix  22 , which forms a continuous and contiguous layer of polymer material around the optical fibers  12  and the color layer  16 . As with the previous embodiments, the printing layer  18  is applied in ink dots  20  over the primary matrix  22 , and the secondary matrix  24  is applied around the printing  18  and primary matrix  22 . In the embodiment depicted, the primary matrix  22  and the secondary matrix  24  are both uncolored and unopacified. 
       FIG.  6    depicts an embodiment having both the opacifying layer  14  and the color layer  16 , which are also both distinct from the primary matrix  22  and the secondary matrix  24 . As shown in  FIG.  6   , the opacifying layer  14  is applied over the interior fibers  12   b , and the color layer  16  is applied over the primary matrix  22  and is embedded in the secondary matrix  24 . In the embodiment depicted, the opacifying layer  14  and the color layer  16  both terminate at the last interior fiber  12   b , leaving the indicator fiber  12   a  at each edge of the row unobscured. However, in other embodiments, the color layer  16  or opacifying layer  14  could extend further than the other layer. In embodiments, the opacifying layer  14  and the color layer  16  are located in the first portion  42  above the midline  40 . However, in other embodiments, the opacifying layer  14  and the color layer  16  may be located additionally or alternatively in the second portion  44  below the midline  40 . In embodiments, the opacifying layer  14  has an average thickness T 6  proximal to the midline  40  in the gap between adjacent optical fibers  12  of from 5 μm to 50 μm and an average thickness T 7  over the remainder of the optical fiber  12  of from 5 μm to 50 μm. In embodiments, the color layer  16  has an average thickness T 8  of from 2 μm to 15 μm. 
     In the embodiment of  FIG.  6   , the primary matrix  22  is provided around the optical fibers  12  and the opacifying layer  14 . That is, the optical fibers  12  and opacifying layer  14  are embedded in the primary matrix  22 , which forms a continuous and contiguous layer of polymer material around the optical fibers  12  and the opacifying layer  14 . As with the previous embodiments, the printing  18  is applied in ink dots  20  over the primary matrix  22 , and the secondary matrix  24 , in which the color layer  16  is embedded, is applied around the printing  18  and primary matrix  22 . 
       FIG.  7    depicts another embodiment in which the opacifying layer  14  and the color layer  16  are both contained in the primary matrix  22 . As shown in  FIG.  7   , the opacifying layer  14  is applied over the interior fibers  12   b , and the color layer  16  is applied over the opacifying layer  14 . In embodiments, the opacifying layer  14  and the color layer  16  are located in the first portion  42  above the midline  40 . However, in other embodiments, such as shown in  FIG.  8   , the opacifying layer  14  and the color layer  16  may be located additionally or alternatively in the second portion  44  below the midline  40 . In embodiments, the opacifying layer  14  has an average thickness proximal to the midline  40  in the gap between adjacent optical fibers similar to the average thickness disclosed with respect to the embodiments shown in  FIGS.  4 - 6   . In embodiments, the opacifying layer  14  has an average thickness T 9  over the remainder of the optical fibers  12  of from 2 μm to 10 μm, and the color layer  16  has an average thickness T 10  over the same region of the optical fibers  12  of from 2 μm to 10 μm. 
     In the embodiments of  FIGS.  7  and  8   , the primary matrix  22  is provided around the optical fibers  12 , the opacifying layer  14 , and the color layer  16 . That is, the optical fibers  12 , the opacifying layer  14 , and the color layer  16  are embedded in the primary matrix  22 , which forms a continuous and contiguous layer of polymer material around the optical fibers  12 , the opacifying layer  14 , and the color layer  16 . As with the previous embodiments, the printing  18  is applied in ink dots  20  over the primary matrix  22 , and the secondary matrix  24  is applied around the printing  18  and primary matrix  22 . 
       FIG.  9    depicts an embodiment of an optical fiber ribbon  10  in which two color layers  16   a ,  16   b  are provided within the primary matrix  22 . In particular, a first color layer  16   a  is provided over a first number of the interior fibers  12   b , and a second color layer  16   b  is provided over a second number of the interior fibers  12   b . Further, the color layers  16   a ,  16   b  overlap over at least one of the interior fibers  12   b . In this way, the first color layer  16   a  provides a first region  46  of a first color, a second region  48  of a second color, and an overlap region  50  of a third color. For example, in an embodiment, the first color layer  16   a  is blue, and the second color layer  16   b  is red-orange. In such an embodiment, the overlap region  50  will be purplish in color when viewed from the exterior of the optical fiber ribbon  10 . 
     In embodiments, the color layers  16   a ,  16   b  are located in the first portion  42  above the midline  40 . However, in other embodiments, the color layers  16   a ,  16   b  may be located additionally or alternatively in the second portion  44  below the midline  40 . In embodiments, the color layer  16   a  has an average thickness T 9  over the portion of the optical fibers  12  outside of the region between adjacent optical fibers  12  of 2 μm to 10 μm, and the color layer  16   b  has an average thickness T 11  over the portion of the optical fibers  12  outside of the region between adjacent optical fibers  12  of from 2 μm to 10 μm. 
     In the embodiment  FIG.  9   , the primary matrix  22  is provided around the optical fibers  12  and the color layers  16   a ,  16   b . That is, the optical fibers  12  and the color layers  16   a ,  16   b  are embedded in the primary matrix  22 , which forms a continuous and contiguous layer of polymer material around the optical fibers  12  the color layers  16   a ,  16   b . As with the previous embodiments, the printing layer  18  is applied in ink dots  20  over the primary matrix  22 , and the secondary matrix  24  is applied around the printing layer  18  and primary matrix  22 . 
     Similar to leaving the indicator fibers  12   a  at least partially exposed, the color layers  16   a ,  16   b  and overlap region  50  can help to identify various regions of the optical fiber ribbon  10 . In particular, in optical fiber ribbons  10  having twenty-four or more optical fibers  12 , the color layers  16   a ,  16   b  and overlap region  50  can be alternated to set off particular groups of optical fibers  12 . Further, in embodiments, more than two color layers  16   a ,  16   b  can be provided (e.g., three, four, five, or more different color layers  16   a ,  16   b ) to provide multiple different color regions and overlap regions. 
       FIG.  10    depicts a schematic representation of a processing line  100  for producing an optical fiber ribbon  10  according to the embodiments of the present disclosure. As can be seen in  FIG.  10   , individual optical fibers  12  that are arranged in a planar row enter a first applicator  110 . In the first applicator  110 , the primary matrix  22  is applied around the optical fibers  12  to produce ribbon subunits  15 . In the first applicator  110 , any opacifying layers  14  and/or color layers  16  that are in contact with the optical fibers  12  or are embedded in the primary matrix  22  (such as the embodiments shown in  FIGS.  4 - 9   ) are applied in the first applicator  110 . The  14  ribbon subunits  15  exit the first applicator  110  with the primary matrix  22  and any opacifying layer  14  and/or color layer  16  applicable to the particular embodiment. Thereafter, the ribbon subunits  15  are cured at first curing station  120 , depicted as a UV-curing lamp. After curing, the printing  18  is applied to the primary matrix  22  via one or more printheads  130 . In embodiments, the printheads  130  are inkjet printers that apply the ink dots  20  shown in  FIGS.  1 - 9   . After the printing  18  is applied, the subunits  15  enter a second applicator  140  for application of the secondary matrix  24  to form the optical fiber ribbon  10 . As described above, the secondary matrix  24  itself may be the color layer  16  (e.g.,  FIGS.  3  and  4   ). Additionally, any opacifying layers  14  and/or color layers  16  that are in contact with the primary matrix  22  or embedded in the secondary matrix  24  (such as the embodiments shown in  FIGS.  3  and  6   ) are applied in the second applicator  140 . Upon exiting the second applicator  140 , the optical fiber ribbon  10  is cured again at second curing station  150 , again depicted as a UV-curing lamp. 
       FIG.  11    depicts an embodiment of the first applicator  110 . While the first applicator  110  is shown, the second applicator  140  is substantially similar in design, and the following discussion applies as well to the second applicator  140 . As can be seen in  FIG.  11   , the optical fibers  12  enter the first applicator  110  for application of the primary matrix  22 . The first applicator  110  is depicted with a substantially cubic housing  160  having a first entry port  170  for the material of the primary matrix  22 . The primary matrix  22  material is in a liquid form and is circulating within the housing  160  of the first applicator  110 . The optical fibers  12  enter the housing  160  and are submerged in the primary matrix  22  material. As the optical fibers  12  pass through the first applicator  110 , the primary matrix  22  material coats onto the outer surfaces of the optical fibers  12 . 
     As mentioned above, opacifying layer  14  and/or color layer  16  are applied in the first applicator  110  along with the primary matrix  22 . As shown in  FIG.  11   , a second entry port  180  is provided for the material of the opacifying layer  14  and/or the color layer  16 . In the embodiment depicted, the second entry port  180  is arranged perpendicularly to the first entry port  170 , and on the interior of the housing  160 , slots  190  are formed such that the widths of the slots  190  are transverse to the longitudinal axis of the optical fiber  12 . Further, the width of the slots  190  are designed to substantially match the width of the opacifying layer and/or color layer  16  to be applied to the subunit  15  (or optical fiber ribbon  10  in the case of the second applicator  140 ). Advantageously, the material for the opacifying layer  14  and/or color layer  16  simply be deposited from the slots  190  onto the optical fibers  12  as the circulation of the primary matrix  22  material within the housing  160  brings the material of the opacifying layer  14  and/or color layer  16  into contact with the surface of the optical fibers  12 . 
       FIG.  12    depicts a cross-section of an optical fiber ribbon  10  of the type shown in  FIG.  4    produced in a processing line  100  as shown in  FIG.  10   , including using an applicator  110  as shown in  FIG.  11   . As can be seen in  FIG.  12   , the leftmost optical fiber is the indicator fiber  12   a , and the three other optical fibers depicted are interior fibers  12   b . The interior fibers  12   b  are all coated with an opacifying layer  14  that is contained within the primary matrix  22 . The secondary matrix  24  is the color layer  16 .  FIG.  12    shows a sharp break in the opacifying layer  14  over the leftmost interior fiber  12   b , leaving the indicator ribbon  12   a  uncovered by the opacifying layer  14 . Because the indicator ribbon  12   a  is only partially obscured by the color layer  16  of the secondary matrix  24 , the indicator ribbon  12   a  can be more easily discerned for determination of the polarity of the optical fiber ribbon  10 . 
     Each of the opacifying layer  14 , the color layer  16 , the primary matrix  22 , and the secondary matrix  24  may have a base resin selected from the compositions described below. The opacifying layer  14  and the color layer  16  will contain a pigment, ink, or dye to provide the opacifying or coloring effect, whereas the primary matrix  22  and the secondary matrix  24  (unless used as the opacifying layer  14  or the color layer  16 ) will not contain a pigment, ink, or dye and will be relatively clear or transparent. In embodiments, the base resin is a polymer material that is curable. In a particular embodiment, the base resin is a UV-curable resin comprising an oligomer component, a reactive diluent monomer component, and a photoinitiator. In embodiments, the oligomer is one or more acrylated, methacrylated, or vinyl functional oligomer, and in embodiments, the oligomer has an aliphatic urethane or epoxy backbone. In embodiments, the oligomer comprises 30 wt % to about 80 wt % of the UV-curable resin. In embodiments, the reactive diluent monomer component is one or more reactive diluent monomers having 1 to 5 functional groups of, e.g., acrylate, methacrylate, vinyl ether, or vinyl. In embodiments, the reactive diluent monomer comprises 5 wt % to 65 wt % of the UV-curable resin. In embodiments, the photoinitiator comprises from 0.1 wt % to 10 wt % of the UV-curable resin. In embodiments, the UV-curable resin may also include a variety of other additives in an amount of 0 wt % to 10 wt %, such as antioxidants, catalysts, lubricants, low molecular weight non-crosslinking resins, adhesion promoters, and stabilizers. In embodiments, the base resin comprises from 85 wt % to 99 wt % of the primary matrix  22 , and the pigment comprises the remaining 1 wt % to 15 wt % of the primary matrix  22 . 
     In embodiments of the UV-curable resin, the oligomers may be based on an aliphatic polyether polyol, which is reacted with an aliphatic polyisocyanate and then acrylated. In embodiments, the photoinitiator may include at least one photoinitiating compound selected from the group consisting of bis-acyl phosphine oxide; hydroxycyclohexylphenyl ketone; hydroxymethylphenylpropanone; dimethoxyphenylacetophenone; 2-methyl-1,4-(methyl thio)phenyl-2-morpholino-propanone-1; 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one; 4-(2-hydroxyethyoxy)phenyl-(2-hydroxy-2-propyl)ketone; 1-(4-dodecyl phenyl)-2-hydroxy-2-methylpropan-1-one; diethoxyacetophenone; 2,2-di-sec-butoxy-acetophenone; diethoxyphenyl acetophenone; bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide; and mixtures thereof. 
     Further, in embodiments, examples of suitable reactive diluent monomers include (but are not limited to) isobornyl acrylate; C 6 -C 12  hydrocarbon diol diacrylates; C 6 -C 12  hydrocarbon diol dimethacrylates; tripropylene glycol diacrylate; tripropylene glycol dimethacrylate; neopentyl glycol, diacrylate; neopentyl glycol dimethacrylate; neopentyl glycol propoxylate diacrylate; neopentyl glycol propoxylate dimethacrylate; neopentyl glycol ethoxylate diacrylate; neopentyl glycol ethoxylate dimethacrylate; bisphenol A ethoxylate diacrylate; bisphenol A ethoxylate dimethacrylate; bisphenol A propoxylate diacrylate; bisphenol A propoxylate dimethacrylate; phenoxyethyl acrylate; phenoxyethyl methacrylate; phenoxyethyl ethoxylate acrylate; phenoxyethyl ethoxylate methacrylate; phenoxyethyl propoxylate acrylate; phenoxyethyl propoxylate methacrylate; polyethylene glycol nonylphenylether acrylate; polyethylene glycol nonylphenylether methacrylate; polypropylene glycol nonylphenylether acrylate; polypropylene glycol nonylphenylether methacrylate; isooctyl methacrylate; octyl acrylate; octyl methacrylate; decyl acrylate; decyl methacrylate; isodecyl acrylate; isodecyl methacrylate; lauryl acrylate; lauryl methacrylate; tridecyl acrylate; tridecyl methacrylate; palmitic acrylate; palmitic methacrylate; stearyl acrylate; stearyl methacrylate; cetyl acrylate; cetyl methacrylate; tetrahydrofurfuryl acrylate; tetrahydrofurfuryl methacrylate; isobornyl acrylate; isobornyl methacrylate; dicyclopentenyl acrylate; dicyclopentenyl methacrylate; dicyclopentenyl ethoxylate acrylate; dicyclopentenyl ethoxylate methacrylate; dicyclopentenyl propoxylate acrylate; dicyclopentenyl propoxylate methacrylate; N-vinyl amides and mixtures thereof. Most preferred compounds include isobornyl acrylate, isocyanurate acrylate and particularly tris-hydroxyethyl isocyanurate triacrylate. 
     A variety of suitable opacifiers can be dispersed in the UV-base resin to form the opacifying layer  14 . For a white opacifying layer  14 , exemplary opacifier includes such pigments as TiO 2 , BaSO 4 , ZnO or ZnS. For a black opacifying layer  14 , an exemplary opacifier pigment is carbon black. For a gray opacifying layer  14 , the opacifier may be a combination of white and black pigments. 
     As discussed above, the color layer  16  is tinted with a colorant (e.g., one or more of dye(s), pigment(s), ink(s), etc.) so as to provide an identification element to the optical fiber ribbon  10 . However, the color layer  16  is also configured to be semi-transparent such that the printing  18  can be seen beneath the color layer  16 . As considered herein, the level of transparency of the color layer  16  is selected so as to achieve a desired contrast ratio according to ASTM D2805 of the color layer  16 . As used herein, “contrast ratio” is defined as “the ratio of the reflectance of a film on a black substrate to that of an identical film on a white substrate.” In performing a contrast ratio test according to ASTM D2805, the material tested is spread in an even layer over a test card having both a section of white background and a section of black background. Using reflectometry, the reflectance over the white section and the black section is measured. The ratio of these reflectances is the contrast ratio. 
     The contrast ratio can be adjusted by varying the amount of colorant used in the composition of the color layer  16  and by varying the thickness of the color layer  16 . For example, for a given composition, the contrast ratio of the color layer  16  will increase as the thickness of the color layer  16  increases. Additionally, for a given thickness, the contrast ratio of the color layer  16  will increase as the amount of colorant pigment in the composition of the color layer  16  increases. Table 1 provides the colors of the color layer  16  as defined according the CIE L*c*h* color space, and Table 2 provides the contrast ratio ranges to achieve the desired level of transparency to be able to clearly discern the printing  18  beneath the color layer  16  while still being able to identify the color of the ribbon  10 . 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Color Layer Color (&gt;100 μm on White Background) 
               
            
           
           
               
               
               
               
            
               
                 Secondary 
                 Lightness 
                 Chroma (C*) 
                 Hue Angle 
               
               
                 Color 
                 (L*) 
                 (Full saturation) 
                 (h*) 
               
               
                   
               
               
                 Blue 
                 55-80 
                 60 
                 220-270 
               
               
                 Orange 
                 57-82 
                 60 
                 50-80 
               
               
                 Green 
                 70-95 
                 60 
                 120-190 
               
               
                 Brown 
                 54-79 
                 60 
                 30-80 
               
               
                 Slate 
                 61-86 
                 60 
                  0-360 
               
               
                 White 
                 78-98 
                 60 
                  0-360 
               
               
                 Red 
                 46-71 
                 60 
                 330-50  
               
               
                 Black 
                  0-10 
                 60 
                  0-360 
               
               
                 Yellow 
                 73-98 
                 60 
                  70-120 
               
               
                 Violet 
                 60-85 
                 60 
                 260-330 
               
               
                 Rose 
                 59-84 
                 60 
                  0-25 
               
               
                 Aqua 
                 67-92 
                 60 
                 180-230 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Contrast Ratio of Color Layer as tested according to ASTM 2805 
               
            
           
           
               
               
               
            
               
                   
                 Film thickness 
                 Contrast Ratio 
               
               
                 Material 
                 (microns) 
                 (C w ) 
               
               
                   
               
               
                 White Opacifying layer 
                 20-300 
                 0.2-0.7 
               
               
                 Black Ink 
                 20-300 
                  0.8-0.98 
               
               
                 Yellow Ink 
                 20-300 
                 0.5-0.7 
               
               
                 Color Layer 
                   
                   
               
               
                 Blue 
                 20-300 
                 0.5-0.7 
               
               
                 Orange 
                 20-300 
                 0.3-0.6 
               
               
                 Green 
                 20-300 
                 0.3-0.7 
               
               
                 Brown 
                 20-300 
                 0.3-0.6 
               
               
                 Slate 
                 20-300 
                 0.3-0.5 
               
               
                 White 
                 20-300 
                 0.2-0.7 
               
               
                 Red 
                 20-300 
                 0.5-0.8 
               
               
                 Black 
                 20-300 
                 0.5-0.8 
               
               
                 Yellow 
                 20-300 
                 0.5-0.8 
               
               
                 Violet 
                 20-300 
                 0.5-0.8 
               
               
                 Rose 
                 20-300 
                 0.6-0.9 
               
               
                 Aqua 
                 20-300 
                 0.5-0.8 
               
               
                   
               
            
           
         
       
     
     Taking as an example a blue color layer  16  of 30 μm thickness, the composition of the color layer  16  is selected to achieve a contrast ratio of no more than 0.7 as provided in Table 2 so as to maintain legibility of the underlying printing layer  18 . However, in order to clearly discern the blue color of the ribbon  10 , the composition of the color layer  16  is selected to achieve a contrast ratio of at least 0.5 as provided in Table 2. It is noted that the example of a blue color layer  16  was given, but performance of a contrast ratio measurement according to ASTM 2805 is the same for every color. That is, ASTM 2805 does not define different testing procedures on the basis of color analyzed. 
     In embodiments, the composition of the color layer  16  includes a colorant and a base resin. In embodiments, the colorant is one or more pigments dispersed in a base resin, such as the embodiments of the base resin described above with respect to the opacifying layer  14 . The colorant may be preferably a different composition form the opacifier. A variety of pigments are suitable for use in the pigment-based color dispersion. An exemplary black pigment includes carbon black. Exemplary white pigments include TiO 2 , BaSO 4 , ZnO or ZnS. Exemplary yellow pigments include diarylide yellow and diazo-based pigments. Exemplary blue pigments include phthalocyanine blue, basic dye pigments, and phthalocyanines. Exemplary red pigments include anthraquinone (red), napthole red, monoazo-based pigments, quinacridone pigments, anthraquinone, and perylenes. Exemplary green pigments include phthalocyanine green and nitroso-based pigments. Exemplary orange pigments include monoazo- and diazo-based pigments, quinacridone pigments, anthraquinones and perylenes. Exemplary violet pigments include quinacrinode violet, basic dye pigments and carbazole dioxazine based pigments. The colors of aqua, brown, gray, and rose can be formulated by combining the pigments of the other colors listed above. 
     In accordance with aspects of the present disclosure, fiber types for use in the ribbon may include G.652, G.657.B3, G.657.A2/B2, G.657.A1. These fiber types can have a 1310 nm MFD from 8.2 to 9.6 microns. Individual fiber diameters may range from 250 microns (or 258 microns if colored), 200 microns (or 208 microns if colored), or below. The higher cost, special bend fibers with MFDs at 8.8 μm or other lower MFDs may be used in cases where there is a particularly identified requirement, for example if the stripped fiber is stored outside the cable in a very tight splice tray. In addition, the special bend fibers may enable even smaller diameter cables with higher densities if the fibers are less than 200 microns in diameter, such as 185 microns or less. Moreover, the individual fibers in a ribbon may be set to have a core spacing set to match a predetermined core spacing. For example, individual fibers may not necessarily be abutting in planar alignment but may have gaps in between neighboring fibers, in particular if core spacing for smaller diameter fibers (e.g., 200 micron fiber ribbons) is desired to align with the higher core spacing of a larger diameter fiber ribbon (e.g., 250 micron fiber ribbons). 
     Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more than one component or element and is not intended to be construed as meaning only one. 
     It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.