How do I acquire research experience for a PhD in Computer Science after I've started working in industry?
Actually, you probably already have more &quot;research experience&quot; than many (most?) students entering a doctoral CS program in the US. I doubt that you need anything else. I'm also wondering if you have misconceptions about the purpose of doctoral education. This is where you get a &quot;first&quot; significant research experience and show the world that you can do that.
It isn't a place where you go to prove that you don't need to be there.
If you have an MS from a good place (yes, you do) then you have the necessary background and more to enter PhD studies in the US. Just make a few applications to some places that support the specific sorts of research you are interested in. Get accepted. Find an advisor. Discuss mutual research interests.
But, absent an advisor with &quot;mutual research interests&quot;, the way to proceed as an independent would be to try to find some collaborative relationship with someone who (like an advisor) will work with you and already has some experience. You might be able to find some such person(s) through work contacts or visits to university departments, but it seems to me to be just spinning your wheels when it is admission to a program being what you really need.
Most US applicants to doctoral programs hold only a BS/BA and not many of them have significant research experience. And almost always that will have been guided by some professor.
Ignore your age. It isn't relevant. But make sure that you are able to spend three years (or so) with vastly reduced income.
But if you want it - Do It.