An integrated electrooptic Mach-Zehnder modulator with ridge structure has been designed and fabricated by using X-cut LiNbO 3 substrate. The key techniques of LiNbO 3 wet etching and large thick electrode fabricating are contributed to form the ridge structure for the modulator. Experimental results show that the ridge-type optical modulator has much more obvious advantages in increasing the modulation bandwidth compared with a conventional modulator with planar structure.