Athavale, MihirChurch, Stephen A.Wong, Wei WenLow, Andre K.Y.Tan, Hark HoeHippalgaonkar, KedarParkinson, Patrick2026-07-022026-07-02ORCID:/0000-0002-9468-2449/work/219054348ORCID:/0000-0002-7816-537X/work/219058540https://hdl.handle.net/1885/733812279Bottom-up InP/InAsP microring lasers fabricated by selective-area MOCVD offer compact, integrable light sources but, like many bottom-up grown semiconductor microstructures, remain limited by growth-induced variability. Two sequential multi-objective Bayesian optimisation runs were conducted to efficiently improve lasing performance while minimising costly trial growths. The first optimisation achieved a 1.6× reduction in lasing threshold and tuned emission to 1268 nm in the O-band with 100% yield. The second optimisation targeted a lower threshold, longer wavelength, and reduced variance, with two independent growth sets fabricated under identical parameters to verify reproducibility. This run achieved a further 2× reduction in median lasing threshold, lowered variance by 73%, and shifted the median emission to 1333 nm near the C-band. Both sets showed consistent improvements, yet measurable differences in performance revealed persistent morphology-driven variability. Variational autoencoder analysis confirmed that subtle shape variations correlate with performance, emphasising morphology-aware, generative design for reproducible, high-yield photonic integration.en2026-05-2710.1117/12.3098103