Without taking into account any polarization effects, a possible approach to describe the transfer function of the device is to use the transfer matrix theory 10. Design and characterization of transmitter circuit architectures using. Bias controller of machzehnder modulator for electrooptic. In order to model the fmmr modulator, we use the jacobianger function expansion method. Introduction to modulation transfer function when optical designers attempt to compare the performance of optical systems, a commonly used measure is the modulation transfer function mtf. Hence a highly accurate model for microwave and optical propagation in an electrooptic modulator is needed that includes the loss in the modulating electrodes and in the inhomogeneous semicon. External modulators and mathematical modeling of mach zehnder. The derivation of the second term is simplified by noting that the mzi maximum output 1. Transfer function of mzi modulator in asymmetric configuration pag. The allfiber mzi structure for optical dpsk demodulation. When optical designers attempt to compare the performance of optical systems, a commonly used measure is the modulation transfer function mtf. Therefore, the nonlinearity at the output of a siliconbased mzi modulator is originated basically from the operating bias point of the modulator nonlinear transfer function combined with the intrinsic nonlinear response of. Mach zehnder interferometer mzi modulator, resonatorassisted mach zehnder. If a voltage is applied across one of the arms, a phase shift is induced for the wave passing through that arm.
It is well known that a cosine transfer function can present high or low. Similarly, the output of a machzehnder interferometer is given by. Interferometer criteria for waveguide or fiber optic based interferometer. Design, fabrication and analysis of a machzehnder interferometer user.
The design of an mzi modulator is governed by two key properties. Without applied electric field, constructive interference was achieved at the. A simple and fast frequency domain analysis method for. Waveguide linbo3 intensity modulators are mach zehnder type interferometers. Interference of two waves when two monochromatic waves of complex amplitudes u1r and.
A machzehnder modulator is used for controlling the amplitude of an optical wave. Two phase modulators can be placed in parallel using an interferometric structure. The group index ng is used to determine the freespectral rangefsr, which can be visualized as the shift in effective index vs. The output is a result of interference, ranging from.
Mzi modulator with the two voltages on the same arm pag. The incoming light is split into two branches, different phase shifts applies to each path, and then recombined. Since the pulse is related to ng, information always travels slower than the phase velocity vp which is related to neff. Design of gan based optical modulator with machzehnder. The fraction of phase shift required term is calculated as a function of mzi er assuming it is biased at its quadrature point.
Therefore, the nonlinearity at the output of a siliconbased mzi modulator is originated basically from. However, the complexity of the transfer function makes it impossible to utilize the. The modulation transfer function describes how the the amplitude of each frequency component changes, and the phase transfer function describes how the phases are shifted time delayed. Heterodyne technique for measuring the amplitude and phase. The machzehnder modulator mzm has been widely used for broadband photonic analog. Hvam abstract in this letter, we propose a technique based on heterodyne detection for accurately and simultaneously measuring the amplitude and phase transfer functions of. Machzehnder modulator, intensity modulation, and mzm drift 1. Introduction to machzehnder modulator bias controllers laser. These power losses obtained by comparing mzi output power before and after au electrodes depositions. In this theory, 22 matrices are used to represent transformation of fields. Mtf is used for components as simple as a spherical singlet lens to those as complex as a multielement telecentric imaging lens assembly. Amplitude and phase transfer functions of an optical modulator francis p. The input waveguide is split up into two waveguide interferometer arms. The relation between in and out ports of the passive device is written as 5.
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