Without disputing anything said in AwkwardWhale's correct answer, and focusing on on photon behavior specifically (but the same basic theory applies to any quantum system):

In modern optics, we have tools that are extremely precise and can probe all of the things you mention in great detail. Specifically: a) we have the theory of Fock states (where photon number is precisely known; and b) sources of entangled photon pair (N=2).

Were any of the items you mention a significant factor, it would show up immediately in Bell tests. This is because "noise", "environmental decoherence", and other things would terminate the entanglement. In that case, the entanglement would end and the Bell (CHSH) inequality would not be violated. That doesn't happen.

Instead, entanglement has been demonstrated with very high precision through filters, beam splitters, mirrors, fiber, wave plates and so forth with negligible effect. This has been accomplished over very large distances, from 10 km up to over 100 km. The only thing that has been shown to make much difference is when entangled photons travel through the atmosphere.

So you can see from these situations, such optical gear makes virtually no impact at all. Here is a basic example:

Violation of Bell inequalities by photons more than 10 km apart (1998)

Without disputing anything said in AwkwardWhale's correct answer, and focusing on photon behavior specifically (but the same basic theory applies to any quantum system):

In modern optics, we have tools that are extremely precise and can probe all the things you mention in great detail. Specifically: a) we have the theory of Fock states (where photon number is precisely known; and b) sources of entangled photon pair (N=2).

Were any of the items you mention a significant factor, it would show up immediately in Bell tests. This is because "noise", "environmental decoherence", and other things would terminate the entanglement. In that case, the entanglement would end and the Bell (CHSH) inequality would not be violated. That doesn't happen.

Instead, entanglement has been demonstrated with very high precision through filters, beam splitters, mirrors, fiber, wave plates and so forth with negligible effect. This has been accomplished over very large distances, from 10 km up to over 100 km. The only thing that has been shown to make much difference is when entangled photons travel through the atmosphere.

So you can see from these situations, such optical gear makes virtually no impact at all. Here is a basic example:

Violation of Bell inequalities by photons more than 10 km apart (1998)

Without disputing anything said in AwkwardWhale's correct answer, and focusing on on photon behavior specifically (but the same basic theory applies to any quantum system):

In modern optics, we have tools that are extremely precise and can probe all of the things you mention in great detail. Specifically: a) we have the theory of Fock states (where photon number is precisely known; and b) sources of entangled photon pair (N=2).

Were any of the items you mention a significant factor, it would show up immediately in Bell tests. This is because "noise", "environmental decoherence", and other things would terminate the entanglement. In that case, the entanglement would end and the Bell (CHSH) inequality would not be violated. That doesn't happen.

Instead, entanglement has been demonstrated with very high precision through filters, beam splitters, mirrors, fiber, wave plates and so forth with negligible effect. This has been accomplished over very large distances, from 10 km up to over 100 km. The only thing that has been shown to make much difference is when entangled photons travel through the atmosphere.

So you can see from these situations, such optical gear makes virtually no impact at all. Here is a basic example:

Violation of Bell inequalities by photons more than 10 km apart (1998)

Without disputing anything said in AwkwardWhale's correct answer, and focusing on on photon behavior specifically (but the same basic theory applies to any quantum system):

In modern optics, we have tools that are extremely precise and can probe all of the things you mention in great detail. Specifically: a) we have the theory of Fock states (where photon number is precisely known; and b) sources of entangled photon pair (N=2).

Were any of the items you mention a significant factor, it would show up immediately in Bell tests. This is because "noise", "environmental decoherence", and other things would terminate the entanglement. In that case, the entanglement would end and the Bell (CHSH) inequality would not be violated. That doesn't happen.

Instead, entanglement has been demonstrated with very high precision through filters, beam splitters, mirrors, fiber, wave plates and so forth with negligible effect. This has been accomplished over very large distances, from 10 km up to over 100 km. The only thing that has been shown to make much difference is when entangled photons travel through the atmosphere.

So you can see from these situations, such optical gear makes virtually no impact at all. Here is a basic example:

Violation of Bell inequalities by photons more than 10 km apart (1998)