Bob’s set up consists of:
Polarisation beam splitter (PBS) — sends orthogonally polarized light pulses in different arms of the interferometer
Delay line (DL) — optical fiber coil used for splitting optical pulse in time domain
Phase modulator (PM) — encodes classical bits into photon’s phase
Beam splitter (BS) — splits light in two arms with particular power ratio
Single photon detectors (SPD1, SPD2) — “Click” when a single photon is incident on it.
Circulator (round arrow) — directs light to optical paths with respect to the arrow direction.
Optical Attenuator (OA) — attenuates optical pulses
Laser — emits optical pulses

Alice’s set up consists of:
Faraday Mirror (FM) — flips polarization of incident light to orthogonal
Phase modulator (PM) — encodes classical bits into photon’s phase
Storage line (SL) — optical fiber coil to store photons
Variable optical attenuator (VOA) — attenuates optical pulses to single photon state
Beam splitter (BS) — splits light in two arms with particular power ratio
Synchro Detector (SD) — classical photodiode detector used for synchronization

Standard single mode optical fiber carrying light pulses. Can up to 50 km long.