| 摘要 |
The present invention relates to an external-cavity type laser provided with a wavemeter for accurately measuring the wavelength of a laser beam on the basis of the transmission wavelength band of a wavelength-selective filter inserted into a resonator irrespective of the driving current of a laser diode chip. An external-cavity type laser device according to the present invention comprises: a laser diode chip (100) for emitting laser beams; an optical feedback partial reflection mirror (500) partially reflecting the beams emitted from the laser diode chip (100) to feed the same back to the laser diode chip (100); a collimation lens (200) provided on an optical path between the laser diode chip (100) and the optical feedback partial reflection mirror (500) to collimate the beams emitted from the laser diode chip (100); a 45-degree partial reflection mirror (300) for converting the direction of laser beams moving in parallel with a package bottom surface to laser beams moving perpendicularly with respect to a package bottom surface; a wavelength-selective filter (400) for transmitting the beams of a selected certain wavelength; a light intensity monitoring photo diode (600) arranged on the optical path, moving from the collimation lens (200) to the 45-degree partial reflection mirror (300) to pass through the 45 degrees partial reflection mirror (300); a wavelength monitoring photo diode (700) arranged on the optical path moving from the wavelength-selective filter (400) to the 45-degree partial reflection mirror (300) to through the 45 degrees partial reflection mirror (300). The photoelectric current flowing through the wavelength monitoring photo diode (700) changes in magnitude according to the intensity of the optical power oscillating in the laser diode chip (100) and the reflectivity at the wavelength-selective filter (400), and the photoelectric current flowing through the light intensity monitoring photo diode (600) is determined by the intensity of the optical power outputted from the laser diode chip (100). Therefore, the value obtained by dividing the photoelectric current flowing through the wavelength monitoring photo diode (700) by the photoelectric current flowing through the light intensity monitoring photo diode (600) only depends on the reflectivity at the wavelength-selective filter (400). Therefore, the value obtained by dividing the photoelectric current flowing through the wavelength monitoring photo diode (700) by the photoelectric current flowing through the light intensity monitoring photo diode (600) provides information on the wavelength of the laser beams on the basis of the transmission band wavelength of the wavelength-selective filter (400), and the wavelength of the laser beams can be recognized by measuring the same and can be determined as a very accurately preset wavelength. |
