Simultaneous amplitude modulation and wavelength conversion in an asymmetric-duty-cycle periodically poled lithium niobate

We report the theory and experiment for an amplitude modulator and wavelength converter based on an electrodecoated asymmetric-duty-cycle periodically poled lithium niobate (PPLN). In a 56%/44% domain-duty-cycle PPLN crystal, we modulated the amplitude of the 532-nm second-harmonic output and measured a normalized half-wave voltage of 1:1 V d ðlmÞ=leff (cm), where d is the separation of the electrodes and leff is the effective electrode length defined by the PPLN length multiplying the deviation of the domain-duty-cycle from the 50% value. A modulation depth of 85% was obtained in the linear modulation regime. We also derived a unified theory to describe the half-wave voltage for two types of PPLN-based amplitude modulators. 2003 Elsevier Science B.V. All rights reserved. PACS: 42.65.Ky; 42.55.)f