There are disclosed a wavelength monitoring device of tunable laser sources
and a method thereof. A Fabry-Perot etalon is provided to detect the wavelength
drift, and furthermore, a Fabry-Perot laser diode or a light emitting diode is
provided to recognize the channel of the wavelength. The wavelength drift is used
to determine the junction voltage of each corresponding channel in advance. Then,
the actually detected junction voltage of the diode is used to determine the channel
of the wavelength, thereby accurately detecting the actual channel wavelength.
