Method for using on line optic fiber loss monitor

An apparatus for measuring continuously the light attenuation characteristics of a length of an optical fiber as it is drawn comprising:

• an optical fiber preform positioning means to heat said preform to a temperature sufficient to reduce its viscosity to permit it to be drawn;
• drawing means;
• means for holding the starting end of said optical fiber after it is drawn in a fixed position;
• means for converting the light transmitted longitudinally through said optical fiber to derive an electrical signal which varies as a function of the length of said fiber and the attenuation characteristics of said fiber;
• and
• means utilizing said electrical signal, whereby said derived signal may be utilized to obtain an objective measure of the loss per unit length of said fiber for purposes of quality control or identification of the fiber as it is being drawn in terms of its light transmission characteristics.

Apparatus for measuring continuously the light attenuation characteristics of a length of an optical fiber as it is drawn comprising:

• means for providing a modulating signal;
• a light source;
• means for driving said light source to produce a modulated light signal;
• an optical fiber preform end positioning means adjacent the output of said light source;
• means for heating said preform to a temperature sufficient to reduce its viscosity to permit it to be drawn;
• drawing means;
• means for collecting said drawn fiber;
• means for holding the starting end of said optical fiber after it is drawn in a fixed position;
• means adjacent said starting end for converting the light transmitted longitudinally through said optical fiber preform and drawn optical fiber into an electrical signal which varies as a function of the length of said fiber and the attenuation characteristics of said fiber;
• and
• means utilizing said electrical signal, whereby said derived signal may be utilized to obtain an objective measure of the loss per unit length of said fiber for purposes of quality control or identification of the fiber as it is being drawn in terms of its light transmission characteristics.