Patent ID: 9048610
Filing Date: 2015-06-02
Classification: H01S

Abstract:
1. An external cavity tunable laser with 25 GHz frequency interval, comprising a laser cavity end mirror arranged on a laser gain medium, and the laser gain medium, an intracavity collimating lens, an active optical phase modulator for modulating the optical phase of the lasing frequency, a tunable acousto-optic filter and an intracavity total reflection mirror all arranged inside a laser cavity sequentially, the light beam emitted from the laser gain medium is collimated by the intracavity collimating lens, passes through the active optical phase modulator and enters into the tunable acousto-optic filter at Bragg angle, and is diffracted into a zero order diffracted light beam and a first order diffracted light beam by the tunable acousto-optic filter, the first order diffracted light beam is reflected by the intracavity total reflection mirror back into the tunable acousto-optic filter at Bragg angle, and is diffracted again into a zero order diffracted light beam and a first order diffracted light beam, the laser wherein: an active polarization rotator arranged on the opposite side of the tunable acousto-optic filter from the intracavity total reflection mirror for receiving the first order diffracted light beam of the second diffraction by the tunable acousto-optic filter and controlling the polarization direction of linearly polarized incident light; a polarization beam splitter arranged behind the active polarization rotator for total transmission of the parallel polarized incident light and reflecting the vertically polarized incident light into a direction having an angle of 90 degrees with respect to the incident light; a first etalon and a first total reflection mirror, which are arranged in a direction vertical to the optic axis of the first order diffracted light beam of the second diffraction by the tunable acousto-optic filter and used for receiving the vertically polarized light output by the polarization beam splitter and outputting the vertically polarized light to the first total reflection mirror, the first total reflection mirror and the laser cavity end mirror forming a first laser resonant sub-cavity; a second etalon and a second total reflection mirror, which are arranged in the same direction as the optic axis of the first order diffracted light beam of the second diffraction by the tunable acousto-optic filter and used for receiving the parallel polarized light output by the polarization beam splitter and outputting the parallel polarized light to the second total reflection mirror, the second total reflection mirror and the laser cavity end mirror forming a second laser resonant sub-cavity; a radio frequency signal source used for providing radio frequency energy for the tunable acousto-optic filter and adjusting the oscillation frequency of the first and second laser resonant sub-cavity by changing RE frequency; and a laser pumping source, a drive source for the active optical phase modulator, a drive source for the active polarization rotator and a laser drive control circuit.