Aaron J. Pearlmana, Jun Chena,b, Jingyun Fana,b, and Alan Migdalla,b


aOptical Technology Division, National Institute of Standards and Technology

100 Bureau Drive, Mail Stop 8441, Gaithersburg, MD 20899-8441

bJoint Quantum Institute, University of Maryland, College Park, MD 20742



We demonstrate photon-pair production in a phase-matched co-polarized type-I (pump, signal, and idler all having the same polarization) periodically-poled KTiOPO4 (PPKTP) waveguide. The pairs were detected at a rate of 120 Hz per mW of pump power in a 1-nm band with a coincidence to accidental ratio of 8.  With proper waveguide temperature tuning and increased collection efficiency, we expect a dramatic increase in the photon-pair detection rate.  In our setup, a 532-nm pump was focused in the waveguide to produce nondegenerate photon pairs at 810 nm (signal) and 1550 nm (idler). With appropriate filtering to eliminate unwanted photons, the correlated pairs were detected using a pair of single-photon detectors: a silicon-based avalanche photodiode and an InGaAs-based avalanche photodiode for the signal and idler photons, respectively. The coincident counts were registered using a correlator in a start-stop configuration.

Such a waveguide structure could potentially be used as a brighter source of correlated photon pairs than bulk PPKTP crystals [1].  In addition, unlike bulk crystals and fiber sources of photon pairs, a PPKTP waveguide can be easily integrated on-chip, which could prove useful in quantum information applications such as quantum cryptography and linear optical quantum computing.



[1] M. Fiorentino, S. M. Spillane1, R. G. Beausoleil, T. D. Roberts, P. Battle, M. W. Munro, “Spontaneous parametric down-conversion in periodically poled KTP waveguides and bulk crystals.” Optics Express 15 7479 (2007).






Author information:

Name: Aaron J. Pearlman Division: 844.03, Lab: Physics, Building / Room: 221 / A219, Mailstop: 8441,

Phone: 301-975-2342, Fax: 301-869-5700 , Email:, Sigma Xi Member: No,

Mentor: Alan Migdall (221/A213, x2331,, Poster category: Physics