The Optical Modulator Measured (OMM) element shifts the phase of an optical signal based on an electrical signal input. The relationship between the electrical input and the phase shift can be defined using either polynomial coefficients or a table of values. If a table of values is used, the phase. In this section, we will discuss how to implement the layout and the circuit model of the high-speed electro-optic phase modulator (EOPM). = and the chirp is ideally zero.