I you want this to alternate pitch over a whole octave, but can't have the glide over all notes in between, then this is actually not vibrato but tremolo. The obvious way to achieve it is to set up two oscillators (possibly two entire synths) and modulate both in amplitude, with exactly opposite phase. You might for instance achieve this by having two instances of your synth in two tracks, one tuned an octave up, panned hard-left/hard-right, both routed to the same group channel with an auto-pan (auto-balance, actually) effect to achieve the antiphasal modulation, and then both channel mixed by removing the stereo width. In better synths, you patch together an equivalent simply with two oscillators.
That's still not very efficient! For a rather more sophisticated solution, you can, instead of "explicitly" generating the octaves, use the fact that in a normal synth the octaves are already present anyway, as harmonics. So all you really need to do is modulate the ratio of their amplitudes. This could in principle be done with a modulated EQ, but that would be even less efficient than the two-synths solution. A single comb filter will also do the trick. Doing this externally is still cumbersome because you need to track the pitch; but it turns out most digital synths actually have a comb filter built right into their oscillators! It's called a "sync" parameter. Modulating that should be the ideal solution.