We demonstrate spectral shaping of entangled photons in the telecom band with a programmable, fiber-based optical filter. The fine-resolution spectral control permits implementation of length-40 Hadamard codes, through which we are able to verify frequency anticorrelation with a 20-fold increase in total counts over that permitted by the equivalent pair of monochromators at the same input flux. By programming the complex spectral transmission function corresponding to a Mach–Zehnder interferometer, we also construct variations on Franson interferometers that are free from mechanical instabilities, demonstrating spectral phase independence in the slow-detector limit, in which all temporal features are unobservable. Our configuration furnishes a single, compact arrangement for manipulating telecom biphotons and characterizing their quality.
© 2013 Optical Society of America
Original Manuscript: July 22, 2013
Revised Manuscript: September 27, 2013
Manuscript Accepted: October 6, 2013
Published: November 7, 2013
Joseph M. Lukens, Amir Dezfooliyan, Carsten Langrock, Martin M. Fejer, Daniel E. Leaird, and Andrew M. Weiner, "Biphoton manipulation with a fiber-based pulse shaper," Opt. Lett. 38, 4652-4655 (2013)