Surface grating VCSEL-integrated amplifier/beam scanner with high power and single mode operation

We propose and demonstrate a novel surface-grating vertical cavity surface emitting laser (VCSEL)-integrated amplifier/beam scanner. When the surface of the VCSEL section is periodically etched, a single slow-light mode which travels laterally into the amplifier section is selected due to the wavelength selectivity of the grating. The coupled slow light can be amplified with pumping the amplifier above the threshold. The far field angle of the amplified slow light can be continuously tuned through changing the pumping current at the VCSEL. We fabricated the integrated device with a 400 μm long VCSEL section and 1 mm long amplifier section, realizing in a single mode coupling power of over 7 mW and high output power of over 500 mW under pulsed operations of the amplifier. The continuous fan beam steering of 1.5° and a diffraction-limited narrow beam divergence of 0.06° are also achieved. We also fabricated device with extending the amplifier section length to 2 mm. A high single mode power of 1 W under pulsed operations is achieved, which is the record high power operation for single-mode VCSELs. With the performance of both high power and good beam quality, our new device shows great potential to be used as light source for LiDAR and other sensing applications.