  We experimentally demonstrate a high-fidelity entanglement swapping and a
generation of the Greenberger-Horne-Zeilinger~(GHZ) state using
polarization-entangled photon pairs at telecommunication wavelength produced by
spontaneous parametric down conversion with continuous-wave pump light. While
spatially separated sources asynchronously emit photon pairs, the time-resolved
photon detection guarantees the temporal indistinguishability of photons
without active timing synchronizations of pump lasers and/or adjustment of
optical paths. In the experiment, photons are sufficiently narrowed by
fiber-based Bragg gratings with the central wavelengths of 1541~nm and 1580~nm,
and detected by superconducting nanowire single-photon detectors with low
timing jitters. Observed fidelities are 0.84 \pm 0.04 and 0.70 \pm 0.05 for the
entanglement swapping and generation of the GHZ state, respectively.
