Method of fusion splicing single-mode optical fibers using an arc discharge

Claim 3

A method of fusion splicing single-mode optical fibers according to claim 1, in which said conditions include the determination of the arc discharge time according to the distance.

Claim 4

A method of fusion splicing single-mode optical fibers according to claim 1, in which said conditions include the determination of the arc discharge current according to the distance.

Claim 5

A method of fusion splicing single-mode optical fibers according to claim 1, in which said conditions include the determination of the electric energy for an arc discharge according to distance.

Claim 6

A method of fusion splicing single-mode optical fibers according to claim 2, in which, when claddings (16) of the optical fibers (10₁), (10₂) are made of pure silica and the arc discharge current is fixed at substantially 17 mA, said arc discharge time is to determined that, when the distance is smaller than 1 µm, said arc discharge time is determined at substantially 1 sec., when the distance is larger than 4 µm, said arc discharge time is determined at substantially 0.5 sec., and, when the distance is between 1 µm and 4 µm, said arc discharge time is determined at a value linearly varied between 1 sec. and 0.5 sec., according to the distance.

Claim 7

A method of fusion splicing single-mode optical fibers according to claim 3, in which when claddings (16) of the optical fibers (10₁), (10₂) are made of pure silica and the arc discharge time is fixed at 1 sec., said arc discharge current is so determined that, when the distance is smaller than 1 µm, said arc discharge current is determined at substantially 17 mA, when the distance is larger than 4 µm, said arc discharge current is determined at substantially 15 mA, and, when the distance is between 1 µm and 4 µm, said arc discharge current is determined at a value linearly varied between 17 mA and 15 mA, according to the distance.

Claim 8

A method of fusion splicing single-mode optical fibers according to claim 1, in which said measuring step of the distance D comprises the steps of: displaying, on a screen of a TV camera (30), a first image (10₁x) of one (10₁) of the optical fibers (10₁) and (10₂) taken in the X-Z plane, a second image (10₁y) of said one optical fiber (10₁) taken in the Y-Z plane, a third image (10₂x) of the other (10₂) of the optical fibers (10₁) and (10₂) taken in the X-Z plane, and a fourth image (10₂y) of said other optical fibers (10₂) taken in the Y-Z plane; measuring a position C1, on a first scanning line (32) orthogonal to the axis of said one optical fiber (10₁), of the axis of the core (12₁) on said first image (10₁x), and a position C3, on said first scanning line (32), of the axis of core (12₁) on said second image (10₁y); measuring a position F1, on said first scanning line (32), of the axis of said one optical fiber (10₁) on said first image (10₁x), and a position F3, on said first scanning line (32), of the axis of said first optical fibre (10₁) on said second image (10₁y); measuring a position C2, on a second scanning line (34) orthogonal to the axis of said the other optical fiber (10₂), of the axis of the core (12₂) on said third image (10₂x), and a position C4, on said second scanning line (34), of the axis of core (12₂) on said fourth image (10₂y); measuring a position F2, on said second scanning line (34), of the axis of said other optical fiber (10₂) on said third image (10₂x), and a position F4, on said second scanning line (34), of the axis of said other optical fiber (10₂) on said fourth image (10₁y); adjusting the optical fibers (10₁) and (10₂) so that said position C1 of the axis of the core (12₁) on said first image (10₁x) and said position C2 of the axis of the core (12₂) on said third image (10₂x) are aligned with each other and also said position C3 of axis of the core (12₁) on said second image (10₁y) and said position C4 of the axis of the core (12₂) on said fourth image (10₂y) are aligned with each other, whereby the cores (12₁) and (12₂) of optical fibers (10₁) and (10₂) are centered; carrying out equations d1=F1-F2, d2=F3-F4 to pro­vide a distance d1 between positions F1 and F2 and a distance d2 between positions F3 and F4; and carrying out equation D= to provide distance D.