Low-Noise Hybrid Photonic Integrated Violet and Blue Lasers for Quantum Applications

Compact, single-frequency and low-noise integrated photonic laser diodes emitting in the violet (~412 nm) and blue (461 nm) regime are demonstrated. Hybrid-integration of the III-Nitride edge-type laser diodes to a butt-coupled on-chip high-Q resonator was used to achieved ultra-low phase-noise laser operation with ~36 dB side-mode suppression ratio. Both a CMOS-compatible PIC chip with SiN core as well as a new class of PIC platform with crystalline III-Nitride heterostructures was developed and evaluated. Successful demonstration of laser self-injection locking with ultra-narrow emission linewidth was demonstrated for both material platforms. Emission linewidth of only ~ 1 MHz was determined with an external-cavity reference laser implying state-of-the-art phase noise performance and offering a vastly improved form factor. The performance metrics of this novel type of laser suggest the potential implementation of this new technology in next generation, portable quantum systems.