[OPTICAL REVIEW Vol. 3, No. 5 (1996) 341-344]

The Reduction of Harmonic and Intermodulation Distortions with a Cascaded Mach-Zehnder Molulator

Ching-Ting LEE, How-Chiang LEE and Lih-Gen SHEU

Institute of Optical Science, National Central University, Chung-Li, Taiwan, Republic of China

(Received March 25, 1996; Accepted July 2, 1996)

A cascaded two-stage Mach-Zehnder modulator is used to suppress the harmonic and intermodulation distortions simultaneously. The modulation electric fields are applied on the first and second stages in the y and z directions of z-cut lithium niobate crystal, respectively. Because of the inherent versatility of the adjustable modulation parameters, superior linear modulation response can be achieved. When ?50 dB nonlinear suppression is required, the modulation depth of 7.5% can be obtained.

Key words : cascaded Mach-Zehnder modulator, modulation depth, harmonic distortion, intermodulation distortion, transmission factor