Helium–neon laser heads have vast applications in various advance engineering and research fields. He–Ne laser heads in conjunction with optical interferometers are also used for precise and accurate measurements of various dimensional metrology parameters. To achieve reliable measurement observations, periodic calibration of He–Ne laser heads against the primary standard of length (Iodine stabilized He–Ne laser for realization of SI unit “Metre,” wavelength 633 nm) is essential. In the present manuscript, various factors contributing in measurement errors have been recognized and evaluation of measurement uncertainty for calibration of He–Ne laser head is conducted through law of propagation of uncertainty (LPU) and Monte Carlo simulation (MCS) methods. Octave software and R programming language were used for the numerical calculations for Monte Carlo Simulation. The uncertainty values obtained through both the techniques are compared and found to be close. Using LPU, relative combined uncertainty has been ± 3.80 × 10^–10 and relative expanded uncertainty has been ± 7.61 × 10^–10 and using MCS relative combined uncertainty has been ± 3.84 × 10^–10 and expanded uncertainty has been ± 7.68 × 10^–10 obtained.

氦氖激光头在各种先进的工程和研究领域有着广泛的应用。He-Ne 激光头与光学干涉仪结合使用，还可用于各种尺寸计量参数的精确测量。为了实现可靠的测量观察，必须根据长度的主要标准（碘稳定的 He-Ne 激光器，用于实现 SI 单位“米”，波长 633 nm）对 He-Ne 激光头进行定期校准。在本手稿中，已经认识到导致测量误差的各种因素，并且通过不确定性传播定律 (LPU) 和蒙特卡罗模拟 (MCS) 方法对 He-Ne 激光头校准的测量不确定性进行评估。Octave 软件和 R 编程语言用于蒙特卡罗模拟的数值计算。比较通过这两种技术获得的不确定度值，发现它们很接近。使用 LPU，相对组合不确定度为 ± 3.80 × 10^–10和相对扩展不确定度为± 7.61 × 10 ^–10并且使用MCS 相对组合不确定度为± 3.84 × 10 ^–10并且扩展不确定度为± 7.68 × 10 ^–10。