Athermal Mach-Zehnder Interferometer

Schematic of the athermal MZ (left) and example of athermal MZ response (right)

The athermal Mach-Zehnder interferometer (MZI) is a device that provides a filter response which does not change with temperature.

The working principle is based on the optical interference of signals coming from 2 separate arms which are unbalanced (different optical lengths) to match a specified free spectral range. The dimensions of the arms are chosen such that a temperature change provides a null shift in the resonant wavelength. In the configuration proposed, an initial splitter is used to feed the MZ arms and a coupler at the output serves to interfere the signals from the two arms and to allow measurement of the resulting signals. For deployment in applications requiring an athermal filter response such as for wavelength stabilization of laser systems.



  • Broadband
  • Wavelengths: around 3.4 and 4.0 µm


  • Measurements of the fabricated devices