[Animats]

Short range low cost time of flight devices are usually modulated-beam things. You modulate the outgoing light with an RF carrier around 20MHz or so, and then detect that carrier on the receive side. Measure the phase difference between the two to get distance. There's a neat trick borrowed from FM radio to do this - down-convert both input and output signals with the same local oscillator. The resulting down-converted signals have the same phase difference but at a lower frequency, where you can count it easily.

[Groxx]

Are those actually referred to as "time of flight" devices though? Phase-difference measurements are cheap and extremely effective, but I usually see them labeled as such.