Chip-scale power scalable ultraviolet optical source

A method of fabricating a chip scale ultra violet laser source comprising:

• forming an InGaN/GaN MQW blue laser epi structure on a m-plane GaN substrate;
• defining a distributed Bragg reflector master laser in the epi;
• forming a plurality of chip scale ultra violet laser elements on the substrate, wherein forming each chip scale ultra violet laser element comprises:
• forming a back cavity distributed Bragg reflector (DBR);
• forming a tapered gain medium coupled to the back cavity DBR;
• forming an outcoupler grating coupled to the tapered gain medium;
• forming a nonlinear crystal coupled to the outcoupler at a front facet of the nonlinear crystal, wherein the front facet has a first coating that has anti-reflectivity (AR) to a fundamental wavelength of the laser element and high reflectivity (HR) to ultra violet wavelengths, and wherein an exit facet of the nonlinear crystal has a second coating that has HR to a fundamental wavelength of the laser element and AR to the ultra violet wavelengths;
• forming a photodetector coupled to the outcoupler grating;
• and
• forming a phase modulator coupled to the photodetector and coupled to the back cavity DBR.

A heterogeneously integrated chip-scale intra-cavity frequency doubled laser comprising:

• a substrate;
• a plurality of laser elements on the substrate, each laser element comprising a tapered semiconductor optical amplifier;
• a master laser diode on the substrate coupled to each laser element;
• wherein each laser element has a fundamental wavelength;
• wherein each laser element emits a beamlet;
• wherein each beamlet has a wavelength double the fundamental wavelength;
• and
• wherein each laser element is phase locked to the master laser diode.

A method of fabricating a chip scale ultra violet laser source comprising:

• forming an InGaN/GaN MQW blue laser epi structure on a m-plane GaN substrate;
• defining a distributed Bragg reflector master laser in the epi;
• and
• forming a plurality of chip scale ultra violet laser elements on the substrate.