Devices for precise measurements of Laser wavelengths.

A wavemeter is a kind of Interferometer which is used for precise Wavelength measurements on laser beams. The Output Power of the interferometer is monitored while the arm length difference is linearly scanned. The period of the output power with respect to the arm length changes then reflects the wavelength. Typically, the wavemeter output is calibrated by simultaneously recording the signal from a reference laser with known wavelength.