Patent Publication Number: US-2023141958-A1

Title: Section and assembly comprising a plurality of such sections

Description:
TECHNICAL FIELD 
     The present invention relates to a section and an assembly comprising a plurality of sections put together, such as pipelines. 
     STATE OF THE ART 
     Pipes portion are elongated structures, which can be positioned in harsh environment such as under water. 
     The integrity of an assembly of such sections of pipe portions is usually monitored by optical fibers extending along the assembly of these sections, each section comprising an optical fiber and a junction box. In that case, when the pipe portion is arranged to be positioned under water, junction boxes with optical fibers are assembled in situ of the location of pipe portion before being put in the water. This assembly of the optical fibers is functional regarding the goal of the application but raises different problems regarding:
         the easiness of the assembly in harsh environment because all the assemblies are carried out in situ of the location of the pipe portion,   the time spent to assemble the optical fibers in the junction box and in the pipe portion, and   the control of the assembly.       

     An aim of the invention is to overcome at least one of the drawbacks and limits of the prior art, and in particular to present a section:
         easiest to assemble with another section and not time consuming, and/or   more effective in term of the optimization of the operation used for the assembly.       

     SUMMARY OF THE INVENTION 
     A first aspect of the invention concerns a section for an assembly, said assembly being arranged to be assembled by a plurality of sections put together, wherein said section comprises:
         an elongated structure having a left end and a right end,   an optical fiber, preferably surrounding the elongated structure, said optical fiber having a left end and a right end and extending from its left end to its right end in such a way that:
           the left end of the elongated structure and the left end of the optical fiber are located on the same left side of the section, and   the right end of the elongated structure and the right end of the optical fiber are located on the same right side of the section.   
               

     Each end of the optical fiber is enclosed in a junction box, the junction box of the respectively right end or left end of the optical fiber of this section being arranged to be assembled with the junction box of the respectively left end or right end of the optical fiber of another similar section in order to allow an optical connection between the optical fibers of two sections. 
     On the left end of the optical fiber and/or on the right end of the optical fiber, the optical fiber inside the junction box according to the invention may be surrounded by less layer(s) than outside the junction box or by other layer(s) than outside the junction box. 
     On the left end of the optical fiber and/or on the right end of the optical fiber, the at least one layer, surrounding the optical fiber outside the junction box of an assembly according to the invention but not inside the junction box may be connected both to the junction box and to the respectively left end or right end of the section. 
     The junction box, of an assembly according to the invention, of the respectively right end or left end of the optical fiber may be arranged to be connected and locked to a junction box of the respectively left end or right end of the optical fiber of the other similar section of an assembly. 
     The section according to the invention may comprise, for each junction box, a decoupling means arranged to decouple pulling force on the assembly of the elongated structure of this section and on the junction box from the optical fiber. 
     The at least one layer surrounding the optical fiber outside the junction box according to the invention may be connected and integrated with the junction box thanks to the decoupling means. 
     The decoupling means according to the invention may comprise:
         a decoupling structure comprising at least one tube-shaped part, preferably one metallic tube-shaped part, and means for screwing the decoupling structure to the junction box, the decoupling structure that may be positioned between:
           the at least one layer surrounding the optical fiber outside the junction box, and   the optical fiber so that:   the decoupling structure may be surrounded by the at least one layer surrounding the optical fiber outside the junction box and   the optical fiber may be surrounded by the decoupling structure, and   
           connection means surrounding at least one part of the decoupling structure and the at least one layer surrounding the optical fiber outside the junction box, the connection means that may be fixed on the decoupling structure thanks to the means for screwing, the connection means that may be arranged to grip the at least one layer on the decoupling structure.       

     At least one end of the optical fiber according to the invention, preferably each end of the fiber:
         may be equipped with an optical connector, and/or   may be separated in two channels by a coupler, preferably by a wavelength division multiplexing coupler.       

     A removable cover or plug may be positioned on each junction box according to the invention and fixed to its junction box, said removable cover or plug being arranged to close or seal the inside of the junction box, the removable cover or plug being arranged to be removed before assembling two junction boxes together. 
     A second aspect of the invention concerns an assembly comprising a plurality of assembled sections according to the first aspect of the invention. 
     Two assembled junction boxes according to the invention may be:
         covered by a protection cover positioned above the two assembled junction boxes and   fixed to the protection cover.       

     Said protection cover that may be arranged to close or to seal the inside of the two assembled junction boxes from the outside of the two assembled junction boxes. 
     Two assembled junction boxes according to the invention, placed at a connection of a first section and a second section, may be covered by a protection housing covering and insulating from the outside of the protection housing:
         the entire connection of two connected ends of the connected sections and   the two assembled junction boxes,   said protection housing may comprise a top portion and a bottom portion, said top and bottom portions may comprise:
           a left end fixed at a right side of the first section of the assembly, and   a right end fixed at a left side of the second section of the assembly.   
               

     Another aspect of the invention concerns a process of assembling a plurality of sections according to the invention, that can comprise the following steps:
         connecting the left end of elongated structure of a second section to the right end of the elongated structure of a first section,   connecting or assembling the junction box enclosing the left end of the optical fiber of the second section to the junction box enclosing the right end of another optical fiber of the first section so as to form two assembled junction boxes.       

     The process according to the invention may comprise:
         fixing the two assembled junction boxes with securing means.       

     The process according to the invention may comprise:
         removing the removable cover or plug positioned on each junction box before connecting or assembling the two junction boxes together.       

     The process according to the invention may comprise:
         connecting together, inside the two assembled junction boxes, the two ends of the two optical fibers of two connected sections.       

     The process according to the invention may comprise:
         connecting together, by splicing inside the two assembled junction boxes, the two ends of two optical fibers of two connected sections, or   connecting an optical connector to at least one free end of the optical fiber of the first section or of the second section comprised in an unassembled junction box to another junction box.       

     The process according to the invention may comprise:
         controlling the optical connection between two optical fibers connected inside two assembled junction boxes by connecting an optical control means to the free end of the optical fiber of the first section or of the second section comprised in an unassembled junction box to another junction box.       

     The process according to the invention may comprise:
         connecting a coupler to the left end of the optical fiber of the second section or to the right end of the optical fiber of the first section in order to separate the end of this separated optical fiber in first and second channels; connecting an optical control means to the first channel of the separated fiber, and, preferably in the same time; connecting the second channel of the separated fiber to an end of the other optical fiber.       

     The process according to the invention may comprise:
         positioning and fixing, by securing means, a protection cover on the two assembled junction boxes.       

     The process according to the invention may further comprise:
         positioning a protection housing, in order to cover and insulate from the outside of the protection housing:   the entire connection of the two connected ends of the connected sections and   the two assembled junction boxes,   fixing a left end of the protection housing at a right side of the first section of the assembly, and   fixing a right end of the protection housing at a left side of the second section of the assembly.       

    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Other advantages and characteristics of the invention will appear upon examination of the detailed description of embodiments, which are in no way limitative, and of the appended drawings in which:
           FIG.  1    schematically shows an elongated assembly, such as pipe portions put together and equipped with junction boxes according to the invention.     FIG.  2 A and  2 B  schematically show two junction boxes according to the invention.     FIG.  3 A ,  FIG.  3 B ,  FIG.  3 C  and  FIG.  3 D  schematically show a junction box according to the invention arranged to be clamped to an end of a section, such as at the end of a pipe portion. These Figures illustrate a method of an assembly of layers surrounding the optical fiber to a junction box according to the invention,     FIG.  4    shows a junction box according to the invention with a removable cover or plug before being assembled with another junction box according to the invention.     FIG.  5    shows two junction boxes according to the invention with their removable cover or plug before the assembly of two junction boxes according to the invention.     FIG.  6 A  and  FIG.  6 B  are an example of removable covers or plugs of each of the two junction boxes according to the invention.     FIG.  7 A  shows the assembly of two junction boxes according to the invention.     FIG.  7 B  shows two junction boxes assembled according to the invention.     FIG.  8 A  and  FIG.  8 B  illustrate a decoupling structure according to the invention.     FIG.  9    and  FIG.  10    illustrate a connection means according to the invention.     FIG.  11    illustrates a junction box according to the invention equipped with a connecting coupler connected with an optical fiber.       

     
    
    
     In the description, the terms “first”, “second” are used as an illustration and are not limitative. They can be reversed. 
     In the description, the terms “left”, “right” are used as an illustration and are not limitative. They can be reversed. 
     These embodiments being in no way limitative, we can consider variants of the invention including only a selection of characteristics subsequently described or illustrated, isolated from other described or illustrated characteristics (even if this selection is taken from a sentence containing these other characteristics), if this selection of characteristics is sufficient to give a technical advantage or to distinguish the invention over the state of the art. This selection includes at least one characteristic, preferably a functional characteristic without structural details, or with only a part of the structural details if that part is sufficient to give a technical advantage or to distinguish the invention over the state of the art. 
     DETAILED DESCRIPTION OF THE FIGURES AND OF REALIZATION MODES OF THE INVENTION 
     We are now going to describe an assembly  100  according to the invention in reference to  FIG.  1   . 
     In the following description, if the word “the” is used for describing an element existing in several copies (for example “the optical fiber”, “the section”, “the junction box”, etc.) it can generally be understood as “each” (respectively for example “each optical fiber of the assembly”, “each section of the assembly”, “each junction box of the assembly”, etc.), or it can be understood as a description of this element for a section  101  or for an end of a section  101  that can be generalized to all the other sections  101  or all the ends of all sections  101 . 
       FIG.  1    schematically shows an assembly  100 , for example, an elongated assembly  100  being arranged to be assembled by a plurality of sections  101  put together, such as pipe portions  101  put together. 
     The assembly  100  comprising a plurality of assembled sections  101 . 
     The assembly  100  comprises a plurality of sections  101  positioned successively one behind the other according to a longitudinal direction. 
     Each section  101  comprises an elongated structure having a left end  102  and a right end  104 . 
     For example, the left end  102  of the elongated structure of a second section  101   2  is arranged to be connected and locked with the right end  104  of the elongated structure of another similar section  101   1  positioned before the second section  101   2 . 
     Two successively following sections are assembled at the level of their ends. 
     In addition, each section  101  comprises:
         an optical fiber  106 , said optical fiber  106  having a left end  108  and a right end  110  and extending from its left end  108  to its right end  110  in such a way that:
           the left end  102  of the elongated structure and the left end  108  of the optical fiber  106  are located on the same left side of the section  101 , and   the right end  104  of the elongated structure and the right end  110  of the optical fiber  106  are located on the same right side of the section  101 .   
               

     Thus, if a section  101  extends along the longitudinal direction, the optical fiber  106  of this section  101  extends along the same longitudinal direction; typically, this fiber  106  extends:
         linearly in the longitudinal direction, i.e. it remains substantially always on the same side around the section  101 , or   while surrounding the section  101 , for example by extending helically around the section  101  and along the longitudinal direction.       

     Each end  108 ,  110  of the optical fiber  106  is enclosed in a junction box  112 . The junction box  112  of the respectively right end  110  or left end  108  of the optical fiber  106  of this section is arranged to be assembled with the junction box  112  of the respectively left end  108  or right end  110  of the optical fiber  106  of another similar section  101 . This allows an optical connection between the optical fibers  106  of the two sections  101  positioned successively behind each other. 
     The assembly of two sections  101   1  and  101   2  is faster and less time consuming. 
     For example, in  FIG.  1   , the junction box  112   L  associated with the second section  101   2  is connected with the junction box  112   R  associated of the first section  101   1 , said first section  101   1  being positioned before the second section  101   2  according to the longitudinal direction. 
     In  FIG.  1    the optical fiber  106  of each section  101  extends across the section  101  along the entire length (i.e. along the longitudinal direction) of the structure  101 . In  FIG.  1   , the optical fiber  106  of each section  101  is inside an inner part (not specifically shown in the drawing) of the section  101 . 
     The optical fibers  106  can be different or identical. 
     In the case illustrated in  FIG.  1   , all optical fibers  106  are identical. 
     In a variant, not shown, the optical fiber  106  surrounds an inner shell of the elongated structure of the section  101 . 
     The junction box  112  of the respectively right end  110  or the left end  108  of the optical fiber  106  is arranged to be connected and locked to a junction box  112  of the respectively left end  108  or right end  110  of the optical fiber  106  of the other similar section of the assembly  100 . Other similar section means a section connected to the left end  102  of the considered section  101  or to the right end  104  the considered section  101 . 
     In  FIG.  1   , the junction box  112  of each section  101  is assembled and locked with a junction box  112  of another similar section  101 . By that way, there is an optical connection between the optical fibers  106  of the two assembled sections  101 . 
     Optical connection means that the optical fibers  106  of the two assembled sections  101  are arranged for a circulation of light between the different assembled sections  101  of  FIG.  1   , i.e. a circulation of light between the different connected optical fibers  106 . Circulation can be seen as a transmission and/or a propagation of light between the different assembled sections  101  of  FIG.  1   . 
     The optical connection between the optical fibers  106  of the two assembled sections  101  is carried out inside the junction box  112 , preferably by splicing the two ends of each optical fiber  106  of the two junction boxes  112  arranged to be assembled together. 
     The optical fiber  106  of each section  101  is assembled with two junction boxes  112   L ,  112   R  at its ends  110 ,  108 . 
     For example, for the second section  101   2 ,
         the left end  108  of the optical fiber  106  (of the section  101   2 ) is assembled with a first junction box  112   L  positioned in the left end  102  of the section  101   2 , and   the right end  110  of the optical fiber  106  (of the section  101   2 ) is assembled with a second junction box  112   R  positioned at the right end  104  of the section  101   2 .
 
At the level of the junction of the two different sections  101   1 ,  101   2 , the two assembled junction boxes  112   L ,  112   R , placed at a connection of the second section  101   2  with the first section  101   1 , are covered by a protection housing  114 .
       

     The protection housing  114  is like a sheath  114 , which protects the elements positioned at a junction of two sections  101 . 
     The protection housing  114  at the level of a junction between section  101   1  and  101   2  comprises a top portion and a bottom portion, said top and bottom portions comprising:
         a left end  116  fixed at a right side of the first section  101   1  of the assembly  100 , and   a right end  118  fixed at a left side of the second section  101   2  of the assembly  100 .       

     The protection housing is for example two half cylinders arranged to be attached to two sides of two sections  101 . 
     The protection housing  114  covers and protects from the outside of the protection housing  114  (especially from water, from dust) the different elements positioned inside the protection housing  114 , such as:
         the entire connection of the two connected ends  102 ,  104  of the connected sections  101   1  and  101   2 , and   the two assembled junction boxes  112   L ,  112   R  of the two sections  101   1 ,  101   2  (or  101   2 - 101   3 ),   a portion of the sections  101   1 - 101   2  (or  101   2 - 101   3 ) and a portion of the optical fiber  106  surrounded by layers  300  (disclosed in  FIG.  3 A  to  FIG.  3 D ) covered by the protection housing  114 .   It means that the protection housing  114  offers mechanical protection from impact as well as protection from water, dust etc.       

     The protection housing  114  is made of heat-resistance material, typically same material as the section  101 , for instance stainless steel, or aluminum or even polymer. 
     We are now going to describe two junction boxes  112   L ,  112   R  according to the invention arranged to be assembled together. 
     The two junction boxes  112  are specifically an example of two junction boxes  112   L  and  112   R  arranged to be assembled at the level of a connection of two sections  101   1  and  101   2  illustrated in  FIG.  1   . 
     For example, on the one hand, the junction box  112  illustrated in  FIG.  2 A  is the junction box  112   L  of the left end  102  of the elongated structure of the second section  101   2 . 
     On the other hand, the junction box  112  illustrated in  FIG.  2 B  is the junction box  112   R  of right end  104  of the elongated structure of the first section  101   1 . 
     However, this example is just an illustration, because as said previously, the optical fiber  106  and/or a section  101  is assembled with two junction boxes  112   R  and  112   L  at its ends. These two junction boxes  112   R  and  112   L  can be reversed. By that situation, the junction box  112   L  illustrated in  FIG.  2 A  can be the junction box  112   R  of right end  104  of the elongated structure of a section  101  and the junction box  112   R  illustrated in  FIG.  2 B  can be the junction box  112  of left end  102  of the elongated structure of a section  101 . 
     The junction boxes  112   R ,  112   L  comprise a stand  206  arranged to receive the optical fiber  106  and a removable cover  402  or plug  402  shown in  FIG.  4    and a protection cover  702  shown in  FIG.  7 A  and  FIG.  7 B . The cover  402  or plug  402  is arranged to be secured to the stand  206  of each the junction boxes  112   R ,  112   L . The protection cover  702  is arranged to be secured to the stand  206  of two assembled junction boxes  112   L ,  112   R . 
     The stand  206  has an elongated shape, for example a rectangular shape. The stand  206  is relatively thin. 
     For example, the stand  206  of the junction box  112   L  has a length L 1  typically 1.5 times longer than its width w 1 . Preferably, the length L 1  of the stand  206  the junction box  112   L  is about of 105 mm and the width w 1  is about of 70 mm. 
     For example, the stand  206  of the junction box  112   R  has a length L 2  at least 1.5 times longer than its width w 2 . 
     In  FIG.  2 A  and  FIG.  2 B , the stands  206  of the junction box  112   R  and  112   L  are of same width. In addition, the length L 1  of the junction box  112   L  can be different from the length L 2  of the junction box  112   R . 
     As illustrated in  FIG.  2   , the length L 1  of the junction box  112   L  is equal to the length L 2  of the junction box  112   R . 
     The stand  206  comprises an outer part  210  and an inner part  212 . The outer part  210  is arranged to receive the removable cover  402  or plug  402  shown in  FIG.  4    and the protection cover  702  shown in  FIG.  7 A  and  FIG.  7 B , all arranged to be secured to the stand  206  of the junction box  112 . 
     The outer part  210  is thicker than the inner part  212  of the stand  206 . For example, the outer part  210  of the stand  206  is at least two time thicker than the inner part  212  of the stand  206 . Preferably, the outer part  210  has a thickness e 1  about 20 mm and the inner part  212  has a thickness e 2  about 10 mm. 
     On the one hand, the inner part  212  of the junction box  112   L  illustrated in  FIG.  2 A  comprises a first protrusion  214 . On the other hand, the inner part  212  of the junction box  112   R  illustrated in  FIG.  2 B  comprises a first cavity  216 . 
     The first protrusion  214  of a junction box  112   L  of the second section  101   2  is arranged to be assembled and/or locked in the first cavity  216  of another junction box  112   R  of another section  101 , for example, with the junction box  112   R  of the first section  101   1 . To lock the first protrusion  214  of a junction box  112   L  with the first cavity  216  of another junction box  112   R , the first protrusion  214  has to be assembled in the first cavity  216  and locked with means for securing (not shown) the first protrusion  214  with the first cavity  216 . The securing means can be, for example, a screw or a pin. 
     For doing that, the two junction boxes  112   L ,  112   R , arranged to be assembled together, comprise at least:
         one first hole  218  positioned in a side of the first protrusion  214  such that the first hole  218  extends in the first protrusion  214  along a longitudinal direction of the width w 1  of the stand  206 , and/or   one first hole  218  extending along the entire longitudinal direction of the width w 1  of the stand  206 . In that case, the at least one first hole  218  extends across the outer part  210  and the inner part  212  of the longitudinal direction of the width w 1  of the stand  206 .       

     The junction box  112   L  comprising the first protrusion  214  comprises a first hole  218  extending along the entire width of the first protrusion  214 . 
     The junction box  112   R  comprising the first cavity  216  comprises first two holes  218  positioned on both sides of the first cavity widthwise w 2  of the junction box  112   R . 
     If a screw is used to assemble the two assembled junction boxes  112   L ,  112   R , then one of the two holes  118  of the junction box  112   R  having the cavity  216  is threaded. In addition, the hole  218  of the junction box  112   L  having the protrusion  214  is threated. 
     The junction box  112  comprises at least one second hole  220  arranged to pass the optical fiber  106  inside the junction box  112 . 
     The junction box  112  comprises a comb  222  arranged to trap the two ends of the optical fibers  106  after being spliced together. 
     A shrink-sleeves (not shown) is used to protect the two ends of the optical fibers  106  spliced together. 
     Another way could be to use a recoating at the two ends of the optical fibers  106  spliced together. 
     In all case, the comb  222  is adapted to accept the two ends of the optical fibers  106  spliced together with their shrink-sleeves or recoating. 
     As shown in  FIG.  2 A  and  FIG.  2 B , the two junction boxes  112   L  and  112   R  comprise each a comb  222 . The two combs provide flexibility for coiling and/or splicing the optical fibers  116 . 
     The stand  206  is made of the same material as the junction box  112 , for instance stainless steel, or aluminum or even polymer. 
     The stand  206  comprises a part  224  forming a guide wall used for the optical fiber  106  winding inside the stand  206 , specifically inside the inner part  212  of the stand  206 . 
     The thickness of the part  224  is thinner than the thickness el of the outer part  210  of the stand  206 . 
     The upper side of the part  224  is below the upper side of the junction box  112  on which a removable cover or plug  402  and/or a protection housing  702  will be arranged. 
     Inside the two junction boxes  112   L ,  112   R , the cladding of the optical fiber  106  surrounds the optical fiber  106 . 
     But, for each junction box  112 , a part of the optical fiber  106 , its left end  108  and/or right end  110  is naked in order to be spliced with another optical fiber  106  of another junction box  112  arranged to be assembled with this junction box  112 . 
     Specifically, the cladding of at least one end of the optical fiber  106  has been removed to a specified length in order to splice two ends of two optical fibers  106 . 
     We are now going to describe a junction box  112  according to the invention arranged to be clamped to an end of a section  101 , such as at the end of a pipe portion, in reference to  FIG.  3 A ,  FIG.  3 B ,  FIG.  3 C  and  FIG.  3 D . 
       FIG.  3 A  schematically shows a junction box  112  according to the invention arranged to be clamped to an end of a section  101 , such as at the end of a pipe portion. 
     The junction box  112  illustrated in  FIG.  3 A  comprises all the elements of the junction box  112  shown in  FIG.  2 A  and  FIG.  2 B . 
     In  FIG.  3 A  to  FIG.  3 D , the junction box  112  comprises a part of the optical fiber  106  of a section  101 . In that case, only the left end  108  of the optical fiber  106  and/or the right end  110  of the optical fiber  106  of a section  101  is illustrated. 
     The optical fiber  106  outside the junction box  112  is surrounded by layers  300 . Those layers  300  comprise:
         at least one layer  31  surrounding the optical fiber  106  outside the junction box  112  but not inside this junction box  112 , and/or   at least one layer  32  surrounding the optical fiber  106  outside the junction box  112  and inside this junction box  112 .       

     Over part of the layer  300 , the layer  31  surrounds the layer  32 . 
     The optical fiber  106  inside the junction box  112  is surrounded by less layer(s) than outside the junction box  112  or by other layer(s) than outside the junction box  112 . 
     The at least one layer  32  comprises, from inside (more precisely from the optical fiber  106 ) towards outside of the cable  300  (more precisely towards outside the layer  32 ):
         a primary coating, typically a plastic coating surrounding the optical fiber  106 . The primary coating fits into the junction box  112  and is winded with the optical fiber  106  around the part  224 , and   a metallic loose tube (stainless steel) in which we have a few fibers and some gel. It means that the optical fiber  106  and the metallic tube make a Fiber in Metal Tube (FIMT). The loose tube fits into the junction box  112  at the level of the second hole  220  but it is not winded inside the junction box  112 .       

     Then, the at least one layer  31  comprises, from inside (more precisely from the layer  32 ) towards outside the cable  300  (towards outside the layer  31 ):
         a stand armor  308  or stainless-steel wires  308  (metal wires stranded around the tube) around the metal tube of the layer  32 , and   then an optical cable outer sheath, typically made of acrylate or of polymer (Polyethylene (PE), Polypropylene (PP), Polyvinyl chloride (PVC) etc.) layer as outer sheath.       

     The at least one layer  31  surrounding the optical fiber  106  outside the junction box  112  but not inside the junction box  112 , is connected both to the junction box  112  and to the respectively the left end  102  or right end  104  of the section  101 . 
     The at least one layer  31  is secured to the junction box  112  via a decoupling means. Specifically, the layer  31  is fixed to the junction box  112  via a decoupling means and a connection means  306  disclosed below. 
     The decoupling means according to the invention comprises the elements illustrated in  FIG.  8 A ,  FIG.  8 B .,  FIG.  9    and  FIG.  10   . Specifically,  FIG.  8 B  is a cross-sectional view of a part of the decoupling means illustrated in  FIG.  8 A . 
     The section  101  comprises, for each junction box  112 , the decoupling means arranged to decouple pulling force on the assembly of the elongated structure of this section  101  and on the junction box  112  from the optical fiber  106 . 
     The decoupling means comprises a decoupling structure  301  comprising at least one tube-shaped part  303 , preferably one metallic tube-shaped part  303 , and means for screwing  302  the decoupling structure  301  to the junction box  112 . 
     The decoupling structure  301  comprises an end  310  arranged to be assembled with a connection means  306 . The end  310  of the decoupling structure  301  is, for example, conical. 
     The decoupling structure  301  is positioned between:
         the at least one layer  31  surrounding the optical fiber  106  outside the junction box  112 , and   the optical fiber  106 , typically, the decoupling structure  301  is positioned between the two layers  31  and  32 .       

     so that:
         the decoupling structure  301  is surrounded by the at least one layer  31  surrounding the optical fiber  106  outside the junction box  112 , and   the optical fiber  106  is surrounded by the decoupling structure  301 .       

     The decoupling means further comprises the connection means  306 , for example a nut  306 , surrounding at least one part of the decoupling structure  301  and the at least one layer  31  surrounding the optical fiber  106  outside the junction box  112 . 
     The connection means  306  according to the invention is illustrated in  FIG.  9    and in  FIG.  10   . Specifically,  FIG.  10    is a cross-sectional view of the connection means  306  illustrated in  FIG.  9   . 
     An inner part of the connection means  306  is arranged to surround a part of an outer side of the decoupling means. 
     The connection means  306  is fixed on the decoupling structure  301  thanks to the means for screwing  302 . The connection means  306  is arranged to grip the at least one layer  31  on the decoupling structure  301 . 
     The at least one layer  31  surrounding the optical fiber  106  outside the junction box  112  is connected and integrated with the junction box  112  thanks to the decoupling means. 
     In  FIG.  3 D , the end  310  of the decoupling structure  301  is surrounded by the stand armor  308  of the at least one layer  31 . The connection means  306  grips the plastic material  308  or the stand armor  308  around the end  310  of the decoupling structure  301 . 
     The metallic tube of the at least one layer  32  passes both inside the connection means  306  and the decoupling structure  301 , and, is inserted into the junction box  112  by the second hole  220 . 
     The metallic tube of the at least one layer  32  always surrounds the optical fiber  106 . 
       FIG.  3 D  shows that the optical fiber  106  passes inside the layers  300 , the connection means  306 , the decoupling structure  301  and is inserted into the junction box  112  by the second hole  220 . 
     The means for screwing  302  of the decoupling structure  301  are of same diameter of the second hole  220  of the junction box  112 . 
     The metallic tube of the at least one layer  32  passes inside the second hole  220  but it does not extend inside the junction box  112 , for example in the inner part  212  of the stand  206 . 
     We are now going to describe a use of a removable cover  402  or plug  402 , in reference to with  FIG.  4   ,  FIG.  5   ,  FIG.  6 A  and  FIG.  6 B , arranged to be fixed to the junction box  112  in order to close the junction box  112 . 
       FIG.  4    shows a junction box  112  according to the invention with a removable cover  402  or plug  402  before being assembled with another junction box  112  according to the invention. 
     The removable cover  402  or plug  402  is arranged to be fixed to the outer part  210  of the stand  206  before the assembly of the two junction boxes  112 . 
     The removable cover  402  or plug  402  protects the junction box  112  from the outside of the junction box  112 . For example, the removable cover or plug  402  protects the inside of the junction box  112  from the dust or from damages caused by the external environment surrounding the junction box  112 . 
     The removable cover  402  or plug  402  is made of rugged material such as stainless steel, or aluminum or even polymer. 
     The removable cover  402  is made of the same material than the junction box  112 , or with Polypropylene (PP) or Polyvinyl chloride (PVC). 
     As shown in  FIG.  5   , a removable cover  402  or plug  402  is positioned on and/or fixed to each junction box  112 . 
     The removable cover  402  or plug  402  is arranged to close or seal the inside of the junction box  112 . 
     For example, the removable cover  402  is used so as to isolate the inside of the junction box  112  containing the optical fiber  106  from the outside of the junction box  112 . 
     In addition, the removable cover  402  or plug  402  is arranged to be removed before assembling two junction boxes  112   L ,  112   R  together. 
     As shown in  FIG.  6 A and  6 B , the removable cover  402  comprises a first flat part  602  arranged to be placed above the stand  206 . 
     The removable cover  402  further comprises a second part  604  positioned perpendicularly to the first part  602 . 
     The geometry of the removable cover  402  depends on and/or is adapted to the junction box  112 . 
     On the one hand, if the junction box  112  comprises a first cavity  216 , as shown in  FIG.  5   , the second part  604  of the removable cover  402  comprises a second protrusion  606  arranged to be assembled in the first cavity  216  when the removable cover  402  is placed above the stand  206  of the junction box  112 . 
     The second protrusion  606  is of same dimension and same geometry of the first cavity  216 . 
     On the other hand, if the junction box  112  comprises a first protrusion  214 , as shown in  FIG.  5   , the second part  604  of the removable cover  402  comprises a second cavity  608  arranged to be positioned above the first protrusion  214  when the removable cover  402  is placed above the stand  206  of the junction box  112 . 
     In that case, the removable cover  402 , comprising the second cavity  608 , does not cover the first protrusion  214  of the junction box  112 . The first protrusion  214  of the junction box  112  exceeds of the ensemble formed by the junction box  112  and the removable cover  402 . 
     The removable cover is relatively thin. For example, the removable cover  402  has a thickness about 2 mm. 
     The removable cover  402  comprises at least one third hole  404  arranged to fix the removable cover  402  above the stand  206  of the junction box  112  by fixing means (not illustrated). 
     In a variant, not shown, the removable cover  402  can be directly fastened to the junction box  112  by interlocking or by other mechanical process or mechanical fastening, which do not require the use of holes (i.e. the third hole  404 ). 
     We are now going to describe the assembly of two junction boxes  112  according to the invention in reference to  FIG.  7 A  and  FIG.  7 B . 
     In addition,  FIG.  7 A  and  FIG.  7 B  disclose a use of a protection cover  702  arranged to be fixed to two assembled junction boxes  112   L ,  112   R  in order to close the two assembled junction boxes  112   L ,  112   R . 
     In  FIG.  7 A , the removable cover  402  of each junction boxes  112  arranged to be assembled is removed from these two junction boxes  112  in order to allow its assembly. 
     The junction boxes  112   L ,  112   R  are prepared in advance before assembling the two junction boxes  112   L ,  112   R . It means that, for example, the ends of each optical fiber  106  arranged to be assembled with another optical fiber  106  of another junction box  112  are already naked. The Fiber cladding has been removed over a length sufficient to allow for cleaving (naked). 
     The decoupling means is installed so as to fix the at least one layer  31  to each junction box  112  arranged to be assembled with another junction box  112 . 
     The two removable covers  402  of the two junction boxes  112   L ,  112   R  are simply removed to assemble two junction boxes  112   L ,  112   R  together. 
     In  FIG.  7 A , the two junction boxes  112   L ,  112   R  are assembled. 
     The two assembled junction boxes  112   L ,  112   R  form a single final box. 
     The optical fibers  106  of each junction box  112  are spliced together, protected by a part made of polymer and positioned in a comb  222  of one of the two assembled junction boxes  112   L ,  112   R . 
     In  FIG.  7 B , the two assembled junction boxes  112  are covered by the protection cover  702  positioned above the two assembled junction boxes  112   L ,  112   R . 
     The protection cover  702  and the two assembled junction boxes  112   L ,  112   R  are of same size. 
     It means that the length L 3  of the protection cover  702  is equal to the addition of the lengths L 1  and L 2  of the junction boxes  112   R  and  112 . 
     The width w 3  of the protection cover  702  is of same width of the junction boxes  112   L  and  112   R . 
     In addition, the protection cover  702  is fixed to the two assembled junction boxes  112   L ,  112   R  with securing means (not show). 
     The third holes  404  used to fix the removable cover  402  are the same as those used to fix the protection cover  702  above the two assembled junction boxes  112   L ,  112   R . 
     The protection cover  702  is arranged to close or seal the inside of the two assembled junction boxes  112   L ,  112   R  from the outside of the two assembled junction boxes  112   L ,  112   R . 
     The protection cover  702  covers and protects from the outside of the protection cover  702  (especially against dust or from water or from damages caused by the external environment surrounding the two assembled junction boxes  112   L ,  112   R ) the different elements positioned inside the two assembled junction boxes  112   L ,  112   R .
         It means that the protection cover  702  offers mechanical protection from impact or etc.       

     The protection cover  702  is made of the same material than the two assembled junction boxes  112 . 
     The protection cover  702  is relatively thin. For example, the protection cover  702  has a thickness about 2 mm. 
     We are now going to describe a junction box  112  according to the invention equipped with a connecting coupler connected with the optical fiber  106 , in reference to with  FIG.  11   . 
     In  FIG.  11   , a wavelength division multiplexing coupler  1102  separates at least one end of the optical fiber  106  in two channels  1106 ,  1104  by a coupler  1102 , preferably. 
     In a variant (not shown), at least one end of the optical fiber  106  is equipped with an optical connector. In that case, the two optical fibers  106  of two junction boxes  112   L ,  112   R  arranged to be assembled together are not spliced but joined together by the use of the connector (not shown). 
     The channel  1106  or  1104  of a junction box  112  positioned at an end of a section  101  is used to measure the splice of two assembled junction boxes  112   L ,  112   R , terminated (i.e. assembled) but yet without protection cover  702 , positioned at the other end of the same section  101 . 
     We are now going to describe a process of an assembly of a plurality of sections  101  according to the invention in reference to  FIG.  1     FIG.  3 A ,  FIG.  3 B ,  FIG.  3 C , and  FIG.  3 D ,  FIG.  4   ,  FIG.  5   ,  FIG.  7 A  and  FIG.  7 D . 
     Before being in the field, the process according to the invention comprises an assembling phase. The assembling phase comprises, for any section  101 :
         receiving the section  101  with its cable  300  surrounding the optical fiber  106 ,   inserting the optical fiber  106  and the at least one layer  32  surrounding the optical fiber  106  inside the junction box  112  at each end of the section  101 , and   fastening the at least one layer  31  surrounding the optical fiber  106  outside the junction box  112  with the decoupling structure  301  and the connection means  306 .       

     For example, in the case of the section  101   2 , it means that the assembling phase comprises assembling a junction box  112   L  or  112   R  at the level of each end  102  and  104  of the section  101   2 . Thus, the cable  300  connects the section  101   2  with each junction box  112  positioned at the level of the end  102  or  104  of the section  101   2 . 
     In addition, the junction box  112  can be prepared during the assembling phase. It means that the different elements inside the junction box  112  can be ready to be assembled with elements coming from another junction box  112  (of another section, for example from section  101   1  or section  101   3 ) arranged to be assembled with the junction box  112  of the section  101   2 . For example, each end of the optical fiber  106  inside the junction box  112  can be already naked. 
     The removal cover  402  is used to protect the different elements inside the junction box  112  from the outside. 
     In the field, the process according to the invention comprises the following steps:
         connecting the left end  102  of elongated structure of the second section  101   2  to the right end  104  of the elongated structure of the first section  101   1 .       

     In addition, the process comprises removing the removable cover  402  or plug  402  positioned on each junction box  112   R ,  112   L  before connecting or assembling the two junction boxes  112   R ,  112   L  together. 
     Then, the process according to the invention comprises:
         connecting or assembling the junction box  112   L  enclosing the left end  108  of the optical fiber  106  of the second section  101   2  to the junction box  112   R  enclosing the right end  110  of another optical fiber  106  of the first section  101   1  so as to form two assembled junction boxes  112   L ,  112   R .       

     The process according to the invention further comprises fixing the two assembled junction boxes  112   L ,  112   R  with securing means (not shown). 
     The process according to the invention comprises further connecting together, inside the two assembled junction boxes  112   R ,  112   L , the two ends of two optical fibers  106  of two connected sections  101   1 ,  101   2 . This step is carried out by splicing. 
     For example, in the field (i.e. when the two junction boxes  112   R ,  112   L  are assembled together), the cladding of the optical fibers  106  does not need to be removed because it is already been done in the upstream phase, for example during a conception or assembling phase of the junction box  112 . This conception or assembling phase allows saving time so that the assembling of two junction boxes  112   R ,  112   L  is not time consuming. 
     In a variant of the process according to the invention, the end of the optical fiber  106  inside the junction box  112  is naked in the field instead of during the assembling phase. 
     In a variant of the process according to the invention, the process according to the invention comprises connecting an optical connector (not shown) to at least one free end of the optical fiber  106  of the second section  101   2  or of the first section  101   1  comprised in an unassembled junction box  112  to another junction box  112 . This variant of process according to the invention is only used when the two ends of optical fibers  106  are not spliced. 
     When the two junction boxes  112   L ,  112   R  are fixed together, the process according to the invention comprises:
         controlling the optical connection between the two optical fibers  106  connected inside the two assembled junction boxes  112   R ,  112   L by connecting an optical control means to the free end of the optical fiber  106  of the second section  101   2  or of the first section  101   1  comprised in an unassembled junction box  112  to another junction box  112 .       

     For example, the control of the splicing of two optical fibers  106  in two assembled junction boxes  112   L ,  112   R  positioned at the junction between the right end  104  of the first section  101   1  and the left end  102  of the second section  101   2  is carried out:
         either at the free end of the optical fiber  106  of the junction box  112   L  of the first section  101   1      or at the free end of the optical fiber  106  of the junction box  112   R  of the second section  101   2 .       

     It means that the process according to the invention comprises controlling the connection of the left end  108  of the optical fiber  106  of a second section  101   2  with the right end  110  of the optical fiber  106  of another section  101   3  positioned in the side of the right end of the second section  101   2 . 
     Another example of controlling the optical connection between two optical fibers  106  spliced together in two assembled junction boxes  112   L ,  112   R  may be the following. 
     If the optical fibers  106  inside two assembled junction boxes  112   L ,  112   R  are not spliced yet, the process according to the invention comprises:
         connecting a coupler  1102  to the left end  108  of the optical fiber  106  of the second section  101   2  or to the right end  110  of the optical fiber  106  of the first section  101   1  in order to separate the ends  108 ,  110  of this separated optical fiber  106  in first and second channels  1104 ,  1106  of the section  101 ; connecting an optical control means (not shown) to the first channel  1104  of the separated fiber  106 , and, in a same time, connecting the second channel  1106  of the separated fiber  106  to an end of the other optical fiber  106 .       

     The channels  1104  and  1106  are optical fibers. 
     In this example above, the coupler should be made during the assembling phase of the junction box  112  (i.e. before the assembling of two junction boxes  112   L ,  112   R  in the field). Thus, the method starts with an upstream preparation of a Wavelength Division Multiplexing (WDM) coupler  1102  (both channels). The coupler  1102  is prepared (i.e. ready for use), integrated and protected inside the junction box  112  covered with the removable cover  402 . In the field (i.e. where the two junction  112   L ,  112   R  boxes are assembled), the channel  1106  of one of junction box  112  is spliced with an optical fiber  106  or another channel  1106  of another junction box  112 . Then, the channel  1104  of one of the two assembled junction boxes  112   L ,  112   R  (comprising the coupler  1102 ) is used to measure the splice of two channels  1106 / 1106  or  1106 / 106  belonging to two others assembled junction boxes  112   L ,  112   R . Said two other assembled junction boxes  112   L ,  112   R  can be positioned downstream or upstream of the channel  1104  connected to the optical control means. 
     As in the first example of controlling, this second example allows controlling the connection of two optical fibers  106  of two assembled junction boxes  112   L ,  112   R  positioned at the level of a section  101  before or after the section  101  wherein the coupler  1102  is used to separate an optical fiber  106  in two channels  1104 ,  1106 . 
     In this second example, the control of the connection of two optical fibers  106  is carried out at the level of the channel  1104  before closing the protection cover  702  above the two assembled junction boxes  112   L ,  112   R . 
     Theses controls allow verifying the optical connection between two optical fibers  106  assembled together by splicing or by the use of a connector. 
     It means that, some steps of the process, for example the preparation of the WDM coupler, are made upstream (i.e. not in the field where the two junction boxes  112   L ,  112   R  are assembled). The upstream preparation of the WDM coupler allows saving time because in the field, just the assembly of two junction boxes, the splice of two optical fibers  106 , the closing of two assembled junction boxes  112   L ,  112   R  with the protection cover  702 , the step of controlling the splice and the closing with the protection housing  114  have to be made. 
     In addition, these previous steps can be carried out at the same time, simultaneously, allowing obtaining a control that is not time consuming. 
     By that way, we can control the optical connection of two optical fibers assembled together at the level of two assembled junction boxes  112   L ,  112   R  either upstream or downstream of the junction box  112  to which the optical control means is connected. 
     It means that someone can check the splice of the next section  101  while someone else is working on assembling the two junction boxes  112   L ,  112   R  from which the measurement is made. Thus, the process is optimized in order to save time. 
     The optical control means is for example an Optical Time Domain Reflectometer (ODTR). 
     The process according to the invention further comprises positioning and fixing, by securing means, a protection cover  702  on the two assembled junction boxes  112 ,  112 . 
     When the protection cover  702  is put and secured to the two assembled junction boxes  112   L ,  112   R , the process according to the invention further comprises positioning a protection housing  114 . The protection housing  114  allows covering and insulating from the outside of the protection housing  114 :
         the entire connection of the two connected ends  102 ,  104  of the connected sections  101   1  and   the two assembled junction boxes  112   L ,  112   R  at the junction of the section  1011  and  1012 .       

     The process according to the invention comprises fixing a left end  116  of the protection housing  114  at a right side of the first section  101   1  of the assembly  100 , and fixing a right end  118  of the protection housing  114  at a left side of the second section  101   2  of the assembly  100 . 
     Of course, the invention is not limited to the examples, which have just been described, and numerous amendments can be made to these examples without exceeding the scope of the invention. 
     Of course, the different characteristics, forms, variants and embodiments of the invention can be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. In particular, all variants and embodiments described above can be combined with each other.