CC BY 4.0Berisha, ArbnorArbnorBerishaBoerma, HendrikHendrikBoermaKaiser, RonaldRonaldKaiserRunge, PatrickPatrickRungeSchell, MartinMartinSchell2025-11-122025-11-122024https://publica.fraunhofer.de/handle/publica/499186https://doi.org/10.24406/publica-628410.1109/JQE.2024.341208810.24406/publica-62842-s2.0-85196119337Complex coupled distributed feedback (DFB) lasers and sampled grating distributed Bragg reflector (SGDBR) lasers under optical injection locking are investigated to determine lowest noise operation. A noise reduction (frequency and intensity combined) of up to 15 dB was measured utilizing detuned optical injection locking at the relaxation oscillation frequency. Furthermore, 4 dB improvement in frequency noise at 10 kHz offset for higher coupling coefficient DFBs under injection locking was measured. The DFB lasers show more sensitivity to injection locking and have a lower need of injection power while exhibiting better signal to noise ratio compared to an SGDBR.entrueDiffraction gratingsfrequency noiseinjection lockinglaser noisenoise measurementnoise reductionsemiconductor lasersjournal article