The present invention relates to an external resonator type laser equipped with a wavelength measuring device which can be independent of the drive current to accurately measure the wavelength of the laser light based on the transmission wavelength band of the wavelength selective filter is inserted in the resonator of the laser diode chip.
Laser apparatus of the type external resonator according to the present invention comprises a laser diode chip (100) that emits laser light; The laser diode chip optical feedback partial reflection mirror 500 for feedback to the light emitted at 100 to the part reflected by the laser diode chip 100 and the back; And the laser diode chip 100 and the optical feedback partial reflection mirror 500, the light is provided on the path, the laser diode chip collimator crystallized collimating the light emitted from the 100, lens 200 between for package bottom surface a wavelength selective filter 400 to 45 and a partial reflection mirror 300 for switching the direction of the laser beam traveling perpendicular to the laser light traveling horizontally in the package bottom surface, passing through the selected light of a specific wavelength and for , and the collimating lens 200 is 45 degrees, partially reflective mirror 300, a light intensity monitoring photo diode (600) for being disposed on the light path 45 passes through the partial reflection mirror 300, the process proceeds to in a wavelength-selective filter at 400 45 a partial reflection mirror 300, a photodiode 700 for wavelength monitoring is disposed on the light path 45 passes through the partial reflection mirror 300 to proceed to; characterized by comprising a, and wavelength monitoring Photo current flowing in the photodiode 700 is flowing through the laser diode chip 100, the light output intensity and the wavelength selective filter 400, the reflectivity is that the size is changed, the light intensity monitoring photo diode (600) for, depending on at which oscillation in the photocurrent is light since the photoelectric current is determined by the output intensity values ​​divided by the photocurrent flowing through the photo current flowing through a wavelength monitor for the photodiode 700 as an optical intensity monitor photodiode 600 output from the laser diode chip 100 is a wavelength a value that depends only on the reflectivity of the selective filter 400 is to have. Therefore, based on the transmission band wavelength of the value obtained by dividing the photo current flowing through the photo current flowing through the wavelength monitoring photodiode 700 for a photo diode 600, an optical intensity monitor is a wavelength selective filter 400, the information on the laser light wavelength gives, can determine the wavelength of the laser light by measuring this, and may be determined at a predetermined with great precision the wavelength of the laser light wavelength.