Laser and fabrication method therefor

A laser, comprising a package cavity, wherein the package cavity is internally provided with:

• a gain chip, comprising:
• a top layer, comprising a first electrode region and a second electrode region, wherein a first electrical isolation trench is formed between the first electrode region and the second electrode region;
• a bottom layer, comprising a third electrode region, wherein the third electrode region is electrically connected respectively to the first electrode region and the second electrode region to output carriers;
• and
• a light-emitting layer, located between the top layer and the bottom layer, and comprising a light-emitting region, wherein the light-emitting region comprises in sequence connected:
• a first active region, located within a downward projection area of the first electrode region to receive the carriers, and configured to emit a broadband light beam according to injected carriers;
• a passive grating region, located within a downward projection area of the first electrical isolation trench, comprising a grating structure and a waveguide region, and configured to provide a first resonant end face for the laser;
• and
• a second active region, located within a downward projection area of the second electrode region to receive the carriers;
• a wavelength selection assembly, disposed outside the gain chip, located on one side close to the first active region, and configured to select light with a specific wavelength from the light beam emitted by the first active region;
• and
• a reflector, disposed on one side, away from the gain chip, of the wavelength selection assembly, and configured to provide a second resonant end face for the laser, such that a resonant cavity is formed between the passive grating region and the reflector;
• and
• the light beam emitted from the first active region is filtered by the wavelength selection assembly to select the light with the specific wavelength, the light with the specific wavelength oscillates in the resonant cavity to form laser, the laser is transmitted to the second active region through the passive grating region, and the second active region optically amplifies the laser according to the injected carriers.