Low‐Stress Silicon Nitride Platform for Mid‐Infrared Broadband and Monolithically Integrated Microphotonics

A monolithic Mid-IR microphotonics platform is demonstrated by engineered Si-rich and low-stress silicon nitride (SiNx) thin films. A measured optical transmission loss of < 0.2 dB cm-1 is achieved over a broad mid-IR spectrum. Using the SiNx film an efficient mid-IR directional coupler is developed that shows a high extinction ratio of 7 dB upon wavelength scanning (λ = 2.45–2.65 μm).