Principals And Applications Of Optical Phase Modulation

Optical phase modulators are used for many applications in optical communication systems, optical processing and microwave signal processing.Two kinds of the optical phase modulators are discussed in this paper. One is the traditional bulk phase modulator or traditional waveguide phase modulator, which we represent as TPM here. And the other one is a new phase modulation network, which is cascaded by a series of Phase Shifters and directional couplers, represented as PMN.We investigate the characteristics of optical phase modulated signal (OPMS) in this paper. In order to manipulate the OPMS, some useful optical methods are discussed. A new integrated modulator consisting of eight-phase modulator waveguides is proposed and used to realize optical wavelength conversion. We represent this integrated modulator as 8PM here. A large degree of optical frequency shifter is realized using 8PM in this paper.Some meaningful applications based on the principal of phase modulation, such as optical pulse source, microwave filter, multi-wavelength light source are presented at last. The waveform of optical pulse is also simulated at the end of this paper.The paper is organized as follows. In Section One, the bases for selecting of the topic about optical phase modulation are illustrated. In Section Two, the principals of TPM and PMN are discussed in details. In Section Three, the basic characteristics of OPMS in frequency domain and the chirp characteristic of OPMS in time domain are analyzed. In Section Four, a wavelength converter using PMN is described. In Section Five, the performance of the integrated modulator consisting of eight-phase modulator waveguides and the methods to alter the OPMS are discussed in details. In Section Six, Some meaningful applications based on the principal of phase modulation are proposed.