Material Technology

Maintaining polarization in optical fibers (PoF)

Ref.-No. 5332

Keywords: Laser, Polarisationserhaltung, optische Fasern, laser optical fibers, maintenance of polarisation

The invention relates to an apparatus and method for minimizing the polarization deviation of the light at the output of a polarization-maintaining (PM) optical fiber under disturbances of the enviroment  such as temperature, pressure and position changes. By alternately heating and cooling the fiber, the internal birefringence of the PM fiber is modulated within seconds by means of a heating element in the shell (see figure). In this way, the linear polarization at the fiber input can be adjusted with high precision, so as to ensure that the polarization angle of the light at the fiber output remains highly stable up to a precision of 0.01 ° in spite of changes in the environmental conditions.                          


  • Fast modulation of the birefringence of a PM Fiber
  • High-precision polarization preservation at the fiber output
  • Affordable use on all PM fibers with a fiber sheath

Commercial Application

The invention relates to a device, a method and the use of the device in quantum optics, quantum information processing, precision physics, laser spectroscopy, laser interferometry, laser technology, or in atomic clocks, fiber-based data transmission, fiber-based quantum information transmission in quantum networks and / or fiber-based quantum sensors and / or classical sensors. By introducing a heating element into the fiber jacket, each PM fiber can be inexpensively upgraded in this way. Thus, the polarization at the fiber output can be rapidly modulated in situ, without interruptions and with minimal temperature excursion until the incoming polarization is precisely aligned onto one of the two major axes of the PM fiber.

Status Quo

A German patent application was filed. An international PCT patent application is possible. A laboratory-scale prototype was successfully manufactured and laboratory tests performed. On behalf of the University of Bonn, PROvendis offers licenses to interested companies for the method.

An invention of Uni Bonn.

Dr. Thorsten Schaefer
+49 208 9410527