Patent ID: 8908725

Claim:
An external cavity tunable laser, comprising an extracavity collimating lens arranged outside the laser cavity, and a laser output mirror, a laser gain medium, an intracavity collimating lens, an active optical phase modulator and a tunable optical filter all arranged sequentially inside the laser cavity, the laser further comprises: an active polarization rotator arranged behind the tunable optical filter for rotating the polarization direction of incident linearly polarized light by 90 degrees, a polarization beam splifter arranged behind the active polarization rotator with total transmission for incident parallel polarized light and reflecting incident vertically polarized 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 sequentially in the direction vertical to the optic axis of the laser output mirror 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 output mirror forming a first laser resonant sub-cavity, a second etalon and a second total reflection mirror, which are arranged sequentially in the optic axis direction of a laser cavity output lens 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 output mirror forming a second laser resonant sub-cavity, and a laser gain medium pumping device, an active phase modulator drive device, a tunable optical filter drive device, an active polarization rotator drive device and a laser drive control circuit.