Optical guided-beam splitter: an experimental study

Measurements on the reflectance R of a guided-beam splitter have been performed. The fabrication method, based on the use of a thin wire as a mask, produces a groove with a parabolic thickness profile in a planar waveguide. The experimental results demonstrate that the theoretical expression R = tanh(2)delta describes well the observed phenomena, especially when the TM(0) mode is incident on the groove. Additional applications of this device for polarization analysis and mode selection are also discussed.