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Key parameters for laser power stability. | SIMTRUM Photonics Store

Key Parameters for Laser Power Stability.

2022-06-01

Lasers generally use RMS (root mean square) stability to evaluate power or energy, and peak-to-peak stability is more demanding.


RMS stability, the ratio of the root mean square of all collected power (or energy) to the average power (or average energy) during the test time, describing the deviation of the output power (or output energy) from the average power (or average energy) degree of dispersion. Usually in the form of a uniform percentage


Peak-to-peak Stability The percentage of the difference between the maximum value and the minimum value of output power or energy and the average value of power or energy, which represents the variation range of output power within a certain period of time, and is also in the form of a percentage. Generally, the peak-to-peak value will be larger than the RMS.


Variance Σ (measurement value - average) 2 / number of samples, describing the degree to which the sample deviates from its average spread. But the dimensions and measurements do not agree (square relationship).


Standard Deviation The arithmetic square root of the variance, the dimension after rooting is consistent with the original data, which is convenient for us to intuitively observe the degree of deviation of random variables.


Mean Square Error (MSE), Root Mean Square Error (RMSE) Similar to the standard deviation calculation process, but it is compared with the true value, not the mean value; the mean squared error (Mean Squared Error), the root mean square error (Root Mean Square Error) in the formula form and the variance, standard deviation and Not much difference, but there is a clear difference in the physical sense. The difference is that there is a real value in the former application scenario, which measures the deviation of each data from the real value. For example, when we evaluate the error accuracy of a weight scale, we will use a standard quality scale for experiments, and the data of multiple experiments will be the difference that can be made with the true value, and the mean squared error is the mean of the squared sum.


Root mean square value (RMES) The arithmetic square root is calculated from the average of the squares of all the values. In the standard deviation formula, the average value is replaced by 0, which is the root mean square value, which can reflect the effective value of the current physical quantity.


Sorbo Power Meter. The statistics function gives the standard deviation: the statistics screen displays the actual value, minimum value, maximum value, and average value of the power, which can be expressed linearly and logarithmically; standard deviation, maximum/minimum ratio (that is, peak-to-peak stability), sample number and time.