title: Quasi-group-velocity matching using integrated-optic structures.
abstract: We propose a device to compensate for group-velocity mismatch (GVM) effects that limit the efficiency-bandwidth product in nonlinear frequency-mixing devices. Integrated wavelength-dependent delay lines are introduced periodically in a waveguide containing a series of quasi-phase-matching (QPM) gratings. Appropriate choice of the time delays can compensate for GVM. We have demonstrated a two-stage device in a periodically poled lithium niobate waveguide. Two approximately 150-fs-long pulses generated 6 ps apart by second-harmonic generation in two QPM gratings were resynchronized by a fixed delay line, and their relative phase was fine controlled by temperature tuning. This technique, which can be iterated to more than two segments, permits optical frequency mixers with a higher efficiency-bandwidth product than would be possible in a single grating short enough to avoid GVM effects.
authors.affiliation: E L Ginzton Laboratory, Stanford University, Stanford, California 94305, USA. jiehuang@stanford.edu
authors.forename: Jie
authors.initials: J
authors.lastname: Huang
authors.forename: J R
authors.initials: JR
authors.lastname: Kurz
authors.forename: Carsten
authors.initials: C
authors.lastname: Langrock
authors.forename: A M
authors.initials: AM
authors.lastname: Schober
authors.forename: M M
authors.initials: MM
authors.lastname: Fejer