Figure 2
From: Synchronous multi-color laser network with daily sub-femtosecond timing drift
(a) Experimental setup of the synchronous mode-locked laser network. All BOCs are symbolized with “lock symbols” shown under their abbreviations. A sealed lock refers to an in-loop detector; whereas an open lock corresponds to an out-of-loop detector. (b) Detailed schematics of the individual elements. Abbreviations: SH-BOC: second-harmonic balanced optical cross-correlator; SF-BOC: sum-frequency BOC; PLL: phase-locked loop; RF-S: RF synthesizer; FC: fiber collimator; PRM: partially reflecting mirror; PBS: polarization beam splitter; λ/2: half-wave plate; DBS: dichroic beam splitter; FL: focus lens; PPKTP: periodically poled potassium titanyl phosphate crystal; DC: dichroic coating; BPD: balanced photodetector; PD: photodetector; AMP: voltage amplifier; BPF: 1.3-GHz electronic bandpass filter; DBC: dichroic beam combiner; NBS: neutral 50:50 beam splitter; FS: fused-silica plate; BBO: barium borate crystal; IF: interference filter; MD: motorized delay; PM-FS: polarization-maintaining fiber stretcher; PM-DCF: PM dispersion-compensated fiber; Bi-EDFA: PM bi-directional erbium doped fiber amplifier.
