"to become awake, cease to sleep," Old English wæcnan, wæcnian "to rise, awake; spring from, come into being," from Proto-Germanic *waknanan, from a suffixed form of PIE root *weg- "to be strong, be lively." OED regards the ending as the -n- "suffix of inchoative verbs of state," but Barnhart rejects this and says it is simply -en (1).
The figurative sense was in Old English. Transitive sense of "to rouse (someone or something) from sleep" is recorded from c. 1200. For distinctions of usage, see wake (v.). Related: Wakened; wakening.