Approach of Frequency Doubling Digital Modulation Signal Generation Based on Optical Modulation Switch

In this paper, an approach of generating frequency doubling modulation signal including FSK, ASK and PSK is proposed and demonstrated. In the scheme, two intensity Mach-Zehnder modulators (IMs) in parallel are employed to generate the optical carrier suppressed (OCS) signals, a PM and two optical couplers form an optical modulator switch (OMS), which can realize the digital modulation of optical signals and transmit them on the specified path by adjusting the coding signal on the switch. The theoretical and simulation results show that the FSK, ASK and PSK signals with frequency doubling are successfully generated, and the modulation format can be switched simply by adjusting the system parameters.