Photon-bunching measurement after two 25-km-long optical fibers

Journal Article · Fri Apr 01 00:00:00 EST 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.71.042335· OSTI ID:20653292

Halder, M; Tanzilli, S; Riedmatten, H de; Beveratos, A; Zbinden, H; Gisin, N ^[1]

---

1. Group of Applied Physics, University of Geneva, 1211 Geneva 4 (Switzerland)

To show the feasibility of a long-distance partial Bell-state measurement, a Hong-Ou-Mandel experiment with coherent photons is reported. Pairs of degenerate photons at telecommunication wavelength are created by parametric down-conversion in a periodically poled lithium niobate waveguide. The photon pairs are separated in a beam splitter and transmitted via two fibers of 25 km. The wave packets are relatively delayed and recombined on a second beam splitter, forming a large Mach-Zehnder interferometer. Coincidence counts between the photons at the two output modes are registered. The main challenge consists in the trade-off between low count rates due to narrow filtering and length fluctuations of the 25-km-long arms during the measurement. For balanced paths a Hong-Ou-Mandel dip with a net visibility of 47.3% is observed, which is close to the maximal theoretical value of 50% developed here. This proves the practicability of a long-distance Bell-state measurement with two independent sources, as, e.g., required in an entanglement swapping configuration in the scale of tens of kilometers.

• OSTI ID: 20653292
• Journal Information: Physical Review. A, Vol. 71, Issue 4; Other Information: DOI: 10.1103/PhysRevA.71.042335; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
BEAM SPLITTING
BELL THEOREM
CONVERSION
CORRELATIONS
COUNTING RATES
DATA TRANSMISSION
DISTANCE
ENERGY LEVELS
FLUCTUATIONS
LITHIUM COMPOUNDS
MACH-ZEHNDER INTERFEROMETER
NIOBATES
OPTICAL FIBERS
PERIODICITY
PHOTONS
QUANTUM MECHANICS
VISIBLE RADIATION
WAVE PACKETS
WAVEGUIDES
WAVELENGTHS