# US 5,707,564 A · Method for the manufacture of wires stretched according to a predetermined profile > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,564 A - Document ID: US5707564A - Status: Granted - Kind: A - Application number: 08/563,672 - Filed: 1995-11-28 - Granted: 1998-01-13 - Earliest claimed: 1994-11-28 - Assignees: France Telecom - Inventors: Loic Rivoallan - Web page: https://patentgrep.com/patent/US5707564A ## CPC - C03B 37/15: with heat application, e.g. for making optical fibres (fusion-splicing of light guides G02B6/255; treatment of light guides to shape optical elements {G02B6/2835, G02B6/2856}) - C03B 2203/24: Single mode [SM or monomode] - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES ## Abstract A method for the controlled stretching of one or more optical fibers according to a desired profile and a device for its implementation. The method includes several steps. In these steps, a speed V.sub.e =dx.sub.e /dt of flow of the fiber entering the heating chamber is laid down, a relationship f of variation of the diameter D.sub.s of the fiber during exit from the heating chamber is chosen such that D.sub.s =f(x.sub.s) wherein x.sub.s represents the positions, variable in time, of a point on the fiber during exit from the heating chamber, successive stretching operations are performed on the fiber to modify, each time, the diameter D.sub.s of the fiber during exit from the heating chamber, so as to follow the profile defined by the relationship f of variation. The method has application to the making of optic fiber devices. ## Claims ### Claim 1 A method for the controlled stretching of one or more optic fibers as the fibers flow through a heating chamber, comprising the following steps: dictating a speed V.sub.e =dx.sub.e /dt of flow of the fiber entering the heating chamber, choosing a relationship f of variation of the diameter D.sub.s of the fiber such that D.sub.s =f(x.sub.s) in which x.sub.s represents the positions, variable in time, of a point on the fiber during exit from the heating chamber, carrying out successive stretching operations on the fiber to modify, during each said stretching operation, the diameter D.sub.s of the fiber during exit from the heating chamber so as to follow the profile defined by the relationship f of variation. ### Claim 2 A method for the controlled stretching of one or more optic fibers comprising the following steps: dictating a speed V.sub.e =dx.sub.e /dt of flow of the fiber entering the heating chamber, choosing a relationship f of variation of the diameter D.sub.s of the fiber such that D.sub.s =f(x.sub.s) in which x.sub.s represents the positions, variable in time, of a point on the fiber during exit from the heating chamber, carrying out successive stretching operations on the fiber to modify, during each said stretching operation, the diameter D.sub.s of the fiber during exit from the heating chamber so as to follow the profile defined by the relationship f of variation, wherein, to perform the successive stretching operations on the fiber so as to modify, during each said stretching operation, the diameter D.sub.s of the fiber and follow the profile defined by the relationship f of variation, a first value of the diameter D.sub.s of the fiber during exit from the heating chamber is determined, on the basis of the relationship f, as a function of the position x.sub.s of the point on the fiber during exit from the heating chamber, a shift dx.sub.s in position x.sub.s of the point on the fiber is determined to obtain a stretching of the fiber during exit from the heating chamber corresponding to the first value, on the basis of the value of the speed dx.sub.s of flow of the fiber at entry into the heating chamber and of the previously computed value of the diameter D.sub.s, a new position x.sub.s of the point on the fiber during exit from the heating chamber is determined by increasing the value of the previously computed shift dx.sub.s, the operations up to the obtaining of the desired profile are reiterated. ### Claim 3 (depends on 2) A method for the controlled stretching of one or more optical fibers according to claim 2, wherein the relationship enabling the computation of the value of the shift dx.sub.s is the following: dx.sub.s =(D.sub.e.sup.2 /D.sub.s.sup.2).multidot.dx.sub.e. ### Claim 4 (depends on 2) A method for the controlled stretching of one or more optical fibers according to claim 2, wherein the relationship enabling the computation of the value of the shift dx.sub.s is the following: dx.sub.s =(D.sub.e.sup.2 /D.sub.s.sup.2).dx.sub.e +L.(D.sub.e +2D.sub.s).DELTA.D.sub.s /.sup.3. ### Claim 5 (depends on 1) A method for the controlled stretching of one or more optic fibers according to claim 1, wherein a relationship f of variation is chosen so as to apply it to a first length of fiber, and another relationship g of variation is chosen so as to apply it to a second length of fiber. ### Claim 6 (depends on 5) A method for the controlled stretching of one of more optic fibers according to claim 5, wherein the relationship f or the relationships f and g of variation are equations of curves that are derivable in art interval of computation of the diameter of the fiber. ### Claim 7 (depends on 5) A method for the controlled stretching of one or more optic fibers according to claim 5, wherein the relationship f of variation is a linear equation and the relationship g of variation is a parabolic equation. ### Claim 8 (depends on 1) A method for the controlled stretching of one or more optic fibers according to claim 1, wherein the starting point, on the axis, of shifts of the point on the fiber is determined on the basis of the hottest point of the heating chamber. ### Claim 9 A device for the controlled stretching of one or more optic fibers, said device comprising: a heating assembly, means for shifting the fiber, a first computer controlling the means for shifting, and a second computer, wherein said first computer servo-controls the position of the means for shifting on the basis of data elements given by the second computer, the second computer including a means for dictating a speed V.sub.e =dx.sub.e /dt of flow of the fiber entering the heating assembly, means for choosing a relationship f of variation of the diameter D.sub.s of the fiber such that D.sub.s =f(x.sub.s) in which x.sub.s represents the positions, variable in time, of a point on the fiber during exit from the heating assembly and means for carrying out successive stretching operations on the fiber to modify, during each said stretching operation, the diameter D.sub.s of the fiber during exit from the heating assembly so as to follow the profile defined by the relationship f of variation. ### Claim 10 (depends on 9) A device according to claim 9, wherein the heating assembly is a heating chamber in which is disposed a torch and a laser source. ### Claim 11 (depends on 10) A device according to claim 10, wherein the laser source is a CO.sub.2 laser. ### Claim 12 (depends on 9) A device according to claim 9, wherein said second computer also includes means for determining a first value of the diameter D.sub.s of the fiber during exit from the heating assembly, said first value being determined on the basis of the relationship f as a function of the position x.sub.s of the point on the fiber during exit from the heating assembly, means for determining a shift dx.sub.s in position of the point on the fiber to obtain a stretching of the fiber during exit from the heating assembly corresponding to the first value, on the basis of the value of the speed dx.sub.e of flow of the fiber at entry into the heating assembly and of the previously computed value of the diameter D.sub.s, means for determining a new position x.sub.s of the point on the fiber during exit from the heating assembly by increasing the value of the previously computed shift dx.sub.s, and means for reiterating the operations up to the obtaining of the desired profile.