Interferometric Sensor of Wavelength Detuning Using a Liquid Crystalline Polymer Waveplate

• Main Author: Paweł Wierzba
• Format: Article
• Language: English
• Published: MDPI AG 2016-05-01
• Series: Sensors
• Subjects: polarization interferometry; waveplate; liquid crystalline polymer; tunable laser; two-beam interferometer
• Online Access: http://www.mdpi.com/1424-8220/16/5/633

Operation of a polarization interferometer for measurement of the wavelength changes of a tunable semiconductor laser was investigated. A λ/8 waveplate made from liquid crystalline polymer is placed in one of interferometers’ arms in order to generate two output signals in quadrature. Wavelength was measured with resolution of 2 pm in the wavelength range 628–635 nm. Drift of the interferometer, measured in the period of 500 s, was 8 nm, which corresponded to the change in the wavelength of 1.3 pm. If needed, wavelength-dependent Heydemann correction can be used to expand the range of operation of such interferometer.