Calibration of grating based optical spectrum analyzers

In this paper, three methods are used to calibrate a grating-based Optical Spectrum Analyzer (OSA). The first method is used to calibrate OSA over the full spectral range by using a set of well characterized laser sources. These lasers, whose wavelengths cover OSA range, are well characterized using a highly accurate wavemeter. The Accuracy and stability for some lasers are found sufficient to calibrate OSA without the need to have an online measurement with a wavemeter. The second method uses the advantage of phase matching in non-linear crystals to generate frequency doubled light with exactly half the wavelength to measure OSA wavelength scale accuracy, resolution and linearity. In the third method, a Hydrogen Cyanide (H¹³C¹⁴N) gas cell - (HCN) is used as wavelength reference to calibrate OSA in the wavelength range 1533–1557 nm.