I wouldnt use depth jumps as my first option, especially if youre referring to a single leg jump, I would use bounds, stiff leg single leg bounds (prime times)- progressed into stiff leg single leg bounds continuously on the same leg, increasing the speed of the run up as youre capable and develop.
I dont agree that issue with your jumps is the quads, its the hamstring and glute, not being able to "lock up" hard enough to transfer that speed and momentum. It will FEEL like the quad, IF your hamstrings arent strong enough to stiffen up and transfer that horizontal momentum into vertical force. Im not pulling that out of thin air, Ive seen over and over with triple jumpers at lower levels, and high jumpers as well, though it becomes more glaringly obvious in the triple. You have to think of that plant leg as a "lever" rather than a "spring" that can be compressed downwards in a one leg jump.
Of course the quads have to be strong and contribute a ton as well as the calves, but MOST of the time, what youre describing is a weakness of the hamstrings, specifically at high velocities. And just because someone has relatively strong or weak hamstrings in the weight room sense does not make them immune to this at all, they are put in an extended position, and forced to contract very HARD, without much shortening. That is why the primetimes and continuous stiff leg single leg bounding works so well to remedy that issue.
If you were referring to a 2leg jump I would do things completely different, but im assuming youre talking about that issue in a slj.