  Several emerging quantum technologies, including quantum networks, modular
and fusion-based quantum computing, rely crucially on the ability to perform
photonic Bell state measurements. Therefore, photon losses and the 50\% success
probablity upper bound of Bell state measurements pose a critical limitation to
photonic quantum technologies. Here, we develop protocols that overcome these
two key challenges through logical encoding of photonic qubits. Our approach
uses a tree graph state logical encoding, which can be produced
deterministically with a few quantum emitters, and achieves near-deterministic
logical photonic Bell state measurements while also protecting against errors
including photon losses, with a record loss-tolerance threshold.
