The characteristics of four kinds of M-Z modulator configurations have been compared, and the Z-cut coplanar waveguide structure is the best. Using the step phase reversal eletrode structure, we have designed a new type electro-optical waveguide amplitude modulator. Packaged and pigtailed phase-reversal M-Z modulators including 5 sections of electrode have been manfactured. The device with 14.8 GHz modulation bandwidth, half wave voltage of 14 V, extinction ratio of 21.3 dB and fiberdevicefiber insertion loss of 7.6 dB at 1523 nm is obtained.