Optical Wavelength Calibration for Stabilized He–Ne laser 633 nm Using Substitution Method

There is a constant need to regularly calibrate He–Ne laser sources to ensure their precision in various applications. However, such calibration systems are currently not available in Indonesia. For this reason, developing a decent calibration system capable of maintaining He–Ne laser traceability is essential. This paper studies the realization of substitution methods to calibrate stabilized He–Ne lasers. The wavelength of the stabilized He–Ne laser to be calibrated (DUC) and the reference He–Ne laser (Agilent 5519B) were measured by a wavelength meter, Advantest (Q8326), that has sufficient short-time stability. The calculated ratio between both wavelengths was used as a reference value in determining the wavelength of the DUC laser. A calibration of laser head Polytec OPV-503 at 632.8 nm with instability 1.5 × 10⁻⁵, was performed to validate the method. It was found that the DUC has a wavelength of (632.9907 ± 0.0001) nm. The result shows that the calibration system can be used to establish traceability to the SI unit of the metre, particularly for the He–Ne laser with stability greater than 0.0001 nm that we expect to be sufficient for laser displacement interferometer applications, e.g., as the primary standard in vibration calibration.