The input of the light in optical fibres is one of the principal problems encountered by the state of the art.

When we try to enter a beam of light into a fibre, we can note the following phenomena :

• When a penetrating beam has an incidence lower than the angle " of effectiveness " e, the light passes through the face of the fibre and comes out the fibre with a minimum of losses.

• When a penetrating beam has an incidence higher than the aperture q of the fibre (this angle is a physical characteristic of each fibre), the light does not enter almost any more and is transmitted very little. This configuration gives results which we can regard as null.

• Between these two opposed positions, we are in an intermediate state in which the effectiveness of fibre is not very good. The angle (q-e), corresponding to this average effectiveness, is far from being negligible.

Good effectiveness

Average effectiveness

Quasi-null effectiveness

q: Aperture of fibre

e: Angle of effectiveness

Schematic diagram of the effectiveness according to incidence angles

It is important that the angle of incidence formed by the rays of light and the normal with the face of the optical fibre must be the smallest as possible.

So, we designed a family of components called " concols " which one of the functions is to make more colinear the rays striking the front face of optical fibres.

The total efficiency is clearly improved while entering more light and under better conditions.

Good effectiveness

Normally average effectiveness

Normally quasi-null effectiveness

Concol

q: Aperture of fibre

e: Angle of effectiveness

Schematic diagram of the effectiveness according to incidence angles with a concol

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