How to detect the TE mode and TM mode?

[yeyunxiaopan]

If there are TE mode and TM mode in an optical waveguide, how to detect them?

Thank you!

 

[Meir Achuz]

The polarization will be different.

 

[sir-pinski]

To detect the TE mode and TM mode in an optical waveguide, one can use a variety of techniques such as near-field scanning, interferometry, and mode conversion measurements. Near-field scanning involves using a near-field probe to scan the electric and magnetic fields at different points along the waveguide. The TE mode is characterized by a dominant electric field component in the transverse direction, while the TM mode has a dominant magnetic field component in the transverse direction. By analyzing the electric and magnetic fields, one can determine the mode of the waveguide.

Interferometry is another method that can be used to detect the TE and TM modes. In this technique, a beam of light is sent through the waveguide and the resulting interference pattern is analyzed. The interference pattern will be different for the TE and TM modes due to their different field distributions. By comparing the interference patterns, one can determine the mode of the waveguide.

Mode conversion measurements involve launching a known mode into the waveguide and measuring the output mode. By comparing the input and output modes, one can determine the mode conversion efficiency and thus determine the mode of the waveguide. This method is particularly useful for detecting higher order modes in addition to the TE and TM modes.

Overall, there are several techniques available to detect the TE and TM modes in an optical waveguide. Each method has its own advantages and limitations, so it is important to choose the most suitable technique based on the specific requirements and characteristics of the waveguide.