Wavelength Meter Module

GouMax’s high-speed wavelength meter (WLM) is designed for applications to test and measurement equipment. The wavelength meter product is de-signed and produced using GouMax’s proprietary micro-optics and interferometer technology. It accu-rately measures single laser line wavelength with high speed. With the use of wavelength tracking mode of this wavelength meter, the mode hopping of semiconductor lasers can be monitored.

Wavelength meter is also called Wavemeter, which uses beam interference to precisely measure wave-length of laser beams. Wavemeter is not a new kind of instrument. Commercially, there are two variants of scanning wavemeters and static devices with no moving parts.

The scanning wavemeter is based on Michelson interferometer, in which one arm can change its length, leading to Fourier transform spectroscopy. In such a kind of wavemeter, light travels in free space. Water absorption in E-band wavelength range will prevent the wavemeter from determining correct wavelength. Further, to drive the motion of one interference arm, the mechanical wear-out will degrade the precision of repeated wavelength measurements.

The static wavemeter with no moving parts is based on static Fizeau interferometer, which consists of two plane reflecting surfaces with a slight deviation from exact parallelity. With the laser illumination, the fringe pattern of the interferometer, whose period depends on the wavelength, is sampled by a photodiode