Optical current monitor

A method of detecting a current traveling through a conductive material, the method comprising the steps of:

• emitting light from a light source at an output level;
• passing the light through a Faraday material positioned near the conductive material so that the light is rotated in the Faraday material due to a magnetic field induced by the current, thereby producing rotated light;
• polarizing the rotated light to produce polarized, rotated light;
• generating a signal based on the polarized, rotated light using a photodetector;
• determining a characteristic of the current traveling through the conductive material based on the signal;
• and
• modifying the output level of the light source based on the signal so that the signal remains at a reference level when current is not traveling through the conductive material.

An optical current monitor for detecting a current in a conductive material, the optical current monitor comprising:

• a light source for emitting unpolarized light at an output level;
• a first fiber optic cable having a first end and a second end, the first end being coupled to the light source so that the first fiber optic cable receives the unpolarized light;
• a first collimator coupled to the second end of the first fiber optic cable and configured to collimate the unpolarized light, thereby producing collimated light;
• a first polarizer coupled to the first collimator and configured to polarize the collimated light, thereby producing polarized light;
• a Faraday material positioned near the conductive material and configured to receive polarized light from the first polarizer, thereby producing rotated light;
• a second polarizer configured to receive and polarize the rotated light, thereby producing polarized, rotated light;
• a second collimator coupled to the second polarizer and configured to collimate the polarized, rotated light, thereby producing collimated, rotated light;
• a second fiber optic cable having a first end and a second end, the first end being coupled to the second collimator so that the second fiber optic cable receives the collimated, rotated light;
• a photodetector coupled to the second end of the second fiber optic cable and configured to—
• receive the collimated, rotated light, and
• output a signal as a function of the collimated, rotated light;
• and
• a feedback system connected to the photodetector and the light source, the feedback system including—
• a filter circuit configured to receive the signal from the photodetector and filter out undesired signal components, and
• an amplifier connected to the filter circuit and the light source, the amplifier being configured to modify the output level of the light source based on the signal so that the signal remains at a reference level when current is not traveling through the conductive material.

A method of detecting a current traveling through a conductive material, the method comprising the steps of:

• emitting light from a light source at an output level;
• passing the light through a Faraday material positioned near the conductive material so that the light is rotated in the Faraday material due to a magnetic field induced by the current, thereby producing rotated light;
• polarizing the rotated light to produce polarized, rotated light;
• generating a signal based on the polarized, rotated light using a photodetector;
• and
• modifying the output level of the light source based on the signal so that the signal remains at a reference level when current is not traveling through the conductive material.