I've been working as a software engineer after graduating with a Masters last year and right now I'm pretty set on trying for grad school entry next year. The way grad school admission works I have to apply this year. I really need one of the letters of reference to come from my current employer (I am only able to source two academic ones for three that are required).

While my workplace is friendly and very supportive of personal and professional development I am slightly concerned of the potential repercussions of asking for this letter of reference. It would be pretty much like giving a notice several months in advance while the consensus on this website seems to be that the best thing to do is to hide the intention of leaving for as long as possible.

I am thinking of how to handle this in a professional way, while still not screwing myself over. When asking a more senior colleague to write me a reference, is it unprofessional to request them to hide this from management? On the other hand, is it even worth it to keep it from management? My manager is also a developer and we work very closely. I don't have any trouble confiding in them except thinking that maybe they will feel obliged to communicate that higher up and act upon it.