Polarimetric sensor for the optical detection of a magnetic field and polarimetric sensor for the optical detection of an electric current

A polarimetric sensor for the optical detection of an electric current, comprising:

• a) an electric conductor carrying an electric current causing a magnetic field;
• b) a flux concentrator having an air gap and effecting an essentially uniform field orientation of the magnetic field in said air gap;
• c) a permanently assembled sensor unit disposed in said air gap and including at least one polarizer, a Faraday element detecting the magnetic field and an analyzer;
• d) an input optical waveguide;
• e) an output optical waveguide with a core diameter of at least 100 μm;
• f) said sensor unit, said input optical waveguide and said output optical waveguide configured to cause a first light signal emerging from said input optical waveguide to enter said sensor unit in uncollimated and unfocussed form, then to pass through said sensor unit and then to enter said output optical waveguide in uncollimated and unfocussed form as a second light signal;
• g) said Faraday element defining an optical path of said first light signal through said Faraday element having a length of at most 50 times said core diameter of said output optical waveguide;
• and
• h) a prism block being transparent in a wavelength range being used, said prism block disposed in said air gap and said sensor unit embedded in said prism block, said prism block having two bores formed therein perpendicularly to said field orientation for receiving said input optical waveguide and said output optical waveguide, and said prism block having two prism surfaces each inclined at 45° to said field orientation and each effecting a 90° deflection of said first light signal and said second light signal.