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.
© 2004 Optical Society of America
(070.6020) Fourier optics and signal processing : Continuous optical signal processing
(130.2790) Integrated optics : Guided waves
(130.3120) Integrated optics : Integrated optics devices
(190.4390) Nonlinear optics : Nonlinear optics, integrated optics
Jie Huang, J. R. Kurz, Carsten Langrock, A. M. Schober, and M. M. Fejer, "Quasi-group-velocity matching using integrated-optic structures," Opt. Lett. 29, 2482-2484 (2004)