| 摘要 |
PROBLEM TO BE SOLVED: To provide an external resonator type wavelength-variable laser device for achieving high laser mode stability in a long term, by facilitating countermeasures to external environmental temperature change or the secular change of a wavelength-variable filter or a wavelength-variable mirror even in the case of configuring this wavelength variable laser device by using a wavelength variable filter whose transparent band width is original wide. SOLUTION: In an external resonator type semiconductor wavelength-variable laser (13) using a wavelength-variable mirror (8) or a wavelength-variable filter (11) using the refractive index change of liquid crystal, in response to the change of a refractive index to the drive voltage frequency of liquid crystal, a frequency F1 of an AC power supply voltage for driving for controlling the refractive index of liquid crystal is set to a frequency largely different from a resonance frequency FR maximizing the response. In addition to the AC power supply voltage, a frequency dither AC signal F2 in the neighborhood of the FR is superimposed, and the wavelength variable mirror (8) or the wavelength-variable filter (11) is driven. A PD (17) for monitoring the light output of the laser controls the amplitude of the AC power supply voltage for driving so that the amplitude of the dither AC signal F2 can be minimized. COPYRIGHT: (C)2009,JPO&INPIT
|
