When can we expect that underwater exploration, undertaken by robots relying on lasers to communicate to the surface and each other, will become an accepted practice?
Communication from the depths of the seas currently requires a cable connection or acoustic transmission. Cables limit mobility and acoustics are risky because losing communication results in the loss of the vehicle. Acoustic technologies furthermore struggle with distortion and cannot transmit large file sizes, such as images, even over small distances.  The development of lasers which can package and transmit more data underwater will increase applications. [2,3,4]
The global underwater robotics market size is expected to reach $US6.74Bn by 2025.  Applications are foreseen in oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, assisted navigation, and tactical surveillance. 
Researchers have successfully used narrow-beam optics to help overcome the significant absorption and scattering effects of water.  Demonstrations have shown how two underwater vehicles can quickly search for and locate each other.  Lasers have little known environmental impact, and perhaps counterintuitively, require less battery power. [8,9] However, lasers still need to be tested in an ocean environment between a surface vessel and an underwater target. 
 Akyildiz, I. F., Pompili, D., Melodia, T. (2005), Underwater acoustic sensor networks: research challenges Ad Hoc Networks 3:3 pp. 257-279 https://www.sciencedirect.com/science/article/pii/S1570870505000168