Fig. 5: Tuning of the lasing wavelength in the locked-state laser.

Optical spectra showing the wide tunability of the locked-state laser of over 54 nm in wavelength near 3.4 μm. Green, blue, orange, yellow, and purple lines represent lasing wavelength tuning for 0 mW, 24 mW, 37 mW, 66 mW, and 99 mW of electrical power applied to the microheater on top of the ring resonator, respectively. In addition, less than 100 mW of electrical power was applied to the microheater on top of the adjacent bus waveguide for phase matching.