Wavelength-tunable laser

Abstract

The present invention relates to a wavelength-tunable laser, which can tune an oscillating laser wavelength and can be manufactured in a small size, comprising: a laser diode chip () for emitting a laser beam; a partial reflection mirror () for optical feedback, which partially reflects the beam emitted from the laser diode chip () so as to enable the reflected beam to be fed back to the laser diode chip (); a collimation lens () provided on an optical path between the laser diode chip () and the partial reflection mirror () for optical feedback so as to collimate the beam emitted from the laser diode chip (); a wavelength-tunable selective filter () for converting the wavelength transmitted according to the temperature; a phase compensator () of which a refractive index is changed according to the temperature and which offsets a change in the refractive index according to the temperature of the semiconductor laser diode chip () or the wavelength-tunable selective filter (); and a 45 degree reflection mirror () for switching the direction of the laser beam from the laser beam traveling in the horizontal direction with respect to a bottom surface of a package, to the laser beam traveling in the vertical direction with respect to the bottom surface of the package, wherein the laser diode chip (), the wavelength-tunable selective filter (), and the phase compensator () are disposed at an upper part of a thermoelectric element () so as to change the wavelength oscillating according to a change in the temperature of the thermoelectric element ().