Cross strip interferometer configuration

A vertically guided, laterally unguided beam of light traverses a wide, deeply etched strip. The right inset shows a cross section of the strip and introduces the relevant geometrical quantities and the refractive index values.

the computational domain

Parameters t = 0.673 µm, b = 0.444 µm, h = 0.339 µm, L = 10.882 µm, ns = 1.465, nb = 2.01, nt = 2.3, and nc = 1.0 specify a device that acts as a polarizer for light with vacuum wavelengths around 1.3 µm.

Light propagation through the polarizer device

Intensity levels are plotted on a strip cross section along the light path. If the electrical field oscillates in the direction perpendicular to the figure plane, the inserted optical power passes the device (TE polarization, top). Orthogonally polarized light waves are scattered into the surrounding (TM polarization, bottom). Please click on the figures to view an animation of the optical waves.

Light propagation, intensity plots TE wave propagation TM wave propagation

For the device specification given above, our simulations predict a relative power throughput of 97% for TE polarization and of 0.09% for TM polarization. This amounts to a polarization extinction ratio of more than 30 dB and to an insertion loss of about 0.1 dB. Being easily adaptable to a variety of material systems and to TE suppression, the cross strip can implement polarizer functionality into an integrated optics chip on a total length of less than 20 µm, without the requirement of exotic materials or complicated processing steps. The short length and the low loss level qualify these strips for cascading.