Free space optics (FSO) uses visible light communication or infrared light to transmit data wirelessly over the air. It can help solve the "last mile" bottleneck problem by providing high-speed connections between buildings without the need for trenching. FSO has advantages like high data rates up to 2.5 Gbps, easy installation, and high security. However, it also faces challenges from factors like building sway, atmospheric attenuation, and fog that can reduce the signal strength. Mitigation techniques exist for many of these environmental challenges, and FSO is being developed for applications like last mile connections and use on high-altitude platforms.