We propose and fabricate a monolithically integrated quad Mach-Zehnder in-phase quadrature (QMZ-IQ) modulator, where four sub-Mach-Zehnder (sub-MZ) modulators are arranged in an IQ super-structure and integrated in a single LiNbO3 substrate. By feeding different electronics and operating at different bias conditions, it has been deployed to synthesize several different advanced optical modulation formats, like 20- and 80-Gb/s minimum phase-shift keying (MSK), 40-Gb/s quadrature phase-shift keying (QPSK), and 40-Gb/s quadrature amplitude modulation (QAM).