  The magneto-optical activity of high quality transparent thin films of
insulating EuTiO3 (ETO) deposited on a thin SrTiO3 (STO) substrate with both
being non-magnetic materials are demonstrated to be a versatile tool for light
modulation. The operating temperature is close to room temperature and admits
multiple device engineering. By using small magnetic fields birefringence of
the samples can be switched off and on. Similarly, rotation of the sample in
the field can modify its birefringence {\Delta}n. In addition, {\Delta}n can be
increased by a factor of 4 in very modest fields with simultaneously enhancing
the operating temperature by almost 100K.
