A low drive voltage LiNbO3 electro-optic modulator for 2.5 Gbit/s and beyond B-ISDN application

Abstract

Broadband SONET (Synchronous Optical Network), SDH (Synchronous Digital Hierarchy), and ATM (Asynchronous Transfer Mode) are widely deployed in public and private networks. OC-48/SDH-16 equipment of 2.5 Gbit/s and high speed network components beyond 2.5 Gbit/s are gaining popularity in various B-ISDN systems. Wavelength chirping of laser diode (LD) creates a hurdle in Gbit/s directly modulated optical transmitter design. Practically, transmitter consisting of a narrow linewidth LD source and an external electro-optic modulator (EOM) can provide a minimum chirping effect and is suitable for multigigabit transmission.1,2 Currently, the typical drive voltage of 3 GHz LiNbO3 EOM is about 3~4 V at 1310 nm. Therefore, the required high speed electronic drive circuits are costly and thus limits the mass deployment of the external modulated transmitter modules. In this paper, we report the demonstration of a low drive voltage (Vx = 1.7 V) EOM with optical modulation bandwidth of 5 GHz.