The design, optimisation and fabrication of Mach Zehnder type 1.324m and 1.524m wavelength intensity modulators, in Z-cut LiNbO3, is described. Fabrication conditions for waveguides and travelling wave electrode structures, in relation to device passive and active performance, are highlighted. Typical polarisation maintaining fibre pigtailed devices at 1.324m and 1.524m had 6dB fibre-to-fibre loss, with an intrinsic modulation bandwidth of 4GHz. The voltage required for on to off operation of the devices was 5-10V, depending on wavelength and waveguide/electrode geometry, with first null extinction ratios between 20 and 45dB. Variations in these performance figures in relation to waveguide fabrication conditions, asymmetry and cross-coupling effects are discussed. Environmental performance of the fibre pigtailed packaged modulators is demonstrated via temperature cycling, shock and vibration testing.