Intensity distribution in the machzehnder modulator stacked xy slices finally, the power in each core can also be independently traced during a calculation. In this manuscript, we investigate the possible modifications to conventional machzehnder modulator structures to improve the system performance. A figure of meritbased electrooptic machzehnder modulator link penalty estimate protocol d. Machzehnder interferometer an overview sciencedirect topics. Introduction to ixblue machzehnder modulators bias controllers.
The vertical axis shows the mzm output power and the horizontal axis shows the bias voltage. One way of implementing a mach zehnder modulator is a dual electrode structure or a push pull modulator. More sophisticated version of the machzehnder interferometer diagram. In the figure below, the blue curve represents the power in the arm located in the positive x region calculated over a circular area of the same extension as the waveguide core. Zehnder modulator international journal of innovative science. By using a dualelectrode mach zehnder modulator for optical phase modulation, the assignment of the one of the. Study theoretically and numerically the machzehnder interferometer modulator in its different configurations, as a key component in the four methods we use in this project. Vpi may also be referred to as the driving voltage of mzm 102 that is the voltage difference that induces the 1 and 0 of.
Lastly, assume that the single photon consisting of only a single plane wave mode enters only one port of the beam splitter. The structure of the dualdrive mzm has two arms and electrodes. The output is a result of interference, ranging from. When you use a real beamsplitter, it has a finite thickness. Analysis of machzehnder interferometer with one arm loaded. A machzehnder modulator is used for controlling the amplitude of an optical wave. Machzehnder modulator, intensity modulation, and mzm drift 1. Dacx1416 optimized solution to modulator biasing in ratio. Off quadrature biasing of mach zehnder modulator for improved. Optical simulation of a machzehnder modulator beamlab. External modulators and mathematical modeling ofmach. Department of electrical and computer systems engineering. And a new modulator experiment was constructed and many aspects of the experimental apparatus were optimized.
Mach zehnder interferometer now assume that two 5050 beam splitters are in series, such that the outputs of one beam splitter are the inputs of the other beam splitter. Machzehnder michelson sagnac interferometer fabryperot interferometer interferometers is an optical instrument that splits a wave into two waves using a beam splitter and delays them by unequal distances, redirect them using mirrors, recombine them using another beam splitter and detect the intensity of their superposition. The incoming light is split into two branches, different phase shifts applies to each path, and then recombined. This report summarizes the theoretical background, description and results of an experiment conducted in the optical communications and applied photonics laboratory.
The machzehnder interferometer is frequently used in the fields of aerodynamics, plasma physics and heat transfer to measure pressure, density, and temperature changes in gases. Depending on the relative phase acquired by the beam along the two paths the second beamsplitter will re. In our measurement, the time delay is chosen such that. Mach zehnder type electrooptical intensity modulator c.
The corresponding transfer chart is depicted by black curve in fig. The linearity is comparable to a reference lithium niobate mach zehnder interferometer modulator operating at quadrature and over an order of magnitude greater than silicon ring modulators based. Complex phase biasing of silicon machzehnder interferometer. You can achieve linear amplitude modulation with small modulation voltages by biasing the modulator at the 50% transmission point, either with a quarterwave plate or by applying a dc voltage to the modulator. The semiconductor optical amplifier machzehnder interferometer soamzi wavelength converter is an important class of integrated wavelength converters that work for both rz and nrz data formats while also acting as a 2r signal regenerator due to their nonlinear transfer function. High speed silicon mach zehnder modulator ling liao, dean samararubio, michael morse, ansheng liu, dexter hodge intel corporation, sc12326, 2200 mission college blvd. External modulators and mathematical modeling ofmach zehnder. Consider a machzehnder modulator with two identical, nonideal phase.
Gould department of physics university of connecticut storrs, ct 06269, usa phillip. A mach zehnder modulator is used for controlling the amplitude of an optical wave. This optical modulator can be coupled to a light source and a bias control module, which is configured to. An electrooptic switch is a device used in integrated fibre optics. An optical iq modulator iqm including two parallel mach zehnder modulators mzm1, mzm2 generates single sideband data signals. We derive equations that quantify silicon machzehnder interferometer mzi modulator impact upon optical link budget for. Performance analysis of rof link using machzehnder modulator. When biased at the correct point on the transfer function, this device can be used to combine. Analysis and suppression of intermodulation distortion effects in machzehnder modulator for analog optical transmission systems by.
High speed silicon machzehnder modulator ling liao, dean samararubio, michael morse, ansheng liu, dexter hodge intel corporation, sc12326, 2200 mission college blvd. Further, assume that the path lengths are identical. Silicon photonic machzehnder modulator architectures for. The performance of a dual parallel differential machzehnder modulator broadband linearization architecture is analysed. A mzm consists of two phase modulators that change the speed of the light passing through them by changing the refractive index of the medium, proportional to an applied electrical signal. However, there is always a small difference between the. In our measurement, the time delay is chosen such that fm mach zehnder modulator is used to control the amplitude of an optical wave which is given to it. The transfer function of mz modulator is a sine wave function of the input voltage. Large signal analysis of machzehnder modulator intensity. Analysis and suppression of intermodulation distortion. Study theoretically and numerically the machzehnder interferometer optical filter which we use. Bias controller of machzehnder modulator for electrooptic.
The phase shifters are described by a voltagedependent phase. Inp integration of soamzis has been reported 1,2,3 and an. The transfer function of an amplitude modulator between crossed polarizers is a sin2 function. The second uses fabrication geometry and properties of the linearization technique to make a more robust modulator applicable to three of the modulators analyzed. This is equivalent to integrating the location variable out of the voltage function. Broadband linear silicon machzehnder modulators nanooptics. The modulator is represented by its measured smallsignal transfer function, see c, followed by a cosineshaped intensity transfer characteristic as sketched in d. Siliconorganic hybrid soh machzehnder modulators for. When the two arms are recombined, the phase difference between the two waves is. Machzehndertype electrooptical intensity modulator c. The transfer function is just a diagonal matrix of exponentials. Abstractwe analyzed the complex transfer function and modulation spectrum of the machzehnder mz modulator with optical power and. Machzehnder interferometer switch this lesson outlines the design process of an electrooptic 2.
A segmented modulator which shapes the optical spectrum of the modulated signal by resonating sections is presented. The modulator enhances the bandwidth of the slow driving electronics at its input. We utilize various techniques to characterize the residual phase modulation of a waveguidebased machzehnder electrooptical. Integrated machzehnder modulator with two electrodes. Meanwhile, a local oscillator source with a wavelengthadjustable. Precise optical modulation using extinctionratio and. The dualelectrode machzehnder modulator demzm is an external electrooptic modulator that is widely used in radio over fiber rof systems to generate millimeterwaves mmwaves.
A b source of photons 50% reflector 100% reflector figure 2. A method for bias control of a nested mach zehnder mzi optical modulator that generates an optical quadrature amplitude modulated signal qam comprising. A 94 ghz antennacoupled directional coupler modulator was initially demonstrated using an. Chapter 3 experimental study and optimization of oplls. Linearized and high frequency electrooptic modulators thesis. Engineered transfer function inp machzehnder modulator. This application note aims to give intensity modulators users the basics to select and apply the proper rf and bias voltages to their device. Such a modulator is called machzehnder intensity electrooptic modulator or simply machzehnder modulator mzm. Finally, basic bulk electrooptic modulators are described in the fourth section, modulator devices including some design considerations and performance criteria. However, the complexity of the transfer function makes it impossible to utilize the. So far, ive heard that in mach zehnder interferometer, two output should have one constructive interference, and one destructive interference for other. Mach zehnder modulator is used to control the amplitude of an optical wave.
This optical modulator can be coupled to a light source and a bias control module, which is configured to apply an offquadrature bias to the optical modulator. Design, fabrication and analysis of a machzehnder interferometer. Waveguide linbo3 intensity modulators are machzehnder type interferometers. Osa linearized segmentation method for measuring the phase. But, what i had calculated above for the phase shift, doesnt fit with the argument above. Id like to point out again that the provided mfile is no runnable script. To obtain a chirp free signal the two drivers have to be very carefully matched option. A 94 ghz antennacoupled directional coupler modulator was initially demonstrated using an old modulator chip from finbar sheehy.
A control unit 18 generates additional optical single sideband pilot signals ps1, ps2 positioned in a lower and a higher sideband respectively, and also further pilot signals ps3, ps4 in both sidebands. Bbs4 protocol by qpsk modulation using dualelectrode. The whole modulators transfer function hmzm at the. In this figure, we imagine analyzing a candle flame. Analysis of machzehnder interferometer with one arm. Dec 20, 2016 the optical transfer function of a mach zehnder interferometer optical modulator is characterized by a raised cosine or sine transfer function. In our measurement, the time delay is chosen such that fm function of wavelength on a log scale simulated with sparameters for two different bias voltage. A temperature independent driver for machzehnder modulators.
The modulator is represented by its measured smallsignal transfer function, see c, followed by a cosineshaped intensity transfer characteristic as sketched in. The intensity modulators are designed to have equal arms and thus balanced optical paths. The technique based on combining a machzehnder modulator and a double. A linearity segmentation method for measuring the phase shift curve of silicon machzehnder modulators smzms as a function of applied electric field is presented. Off quadrature biasing of mach zehnder modulator for. Maldonado department of electrical engineering the uni y ersity of texas at arlington arlington, texas 1 3. The technique based on combining a mach zehnder modulator and a double.
Osa engineered transfer function inp machzehnder modulator. As the electrooptic transfer characteristic of a mach zehnder modulator is cos2shaped, the modulator will be biased in the linear range between the maximum and minimum and the modulation signal will be superimposed onto the bias voltage. Siliconorganic hybrid soh machzehnder modulators for 100. Two phase modulators can be placed in parallel using an interferometric structure. The discussion presented in this chapter applies to any electrooptic material, any direction of the applied voltage, and any direction of the wave vector. Us20090003840a1 controlling a bias voltage for a mach. A schematic representation of a machzehnder modulator made from waveguides with mismatched lengths where a portion of the waveguide is also a pn junction with an electrical voltage input left, and the optical transmission of the device as a function of wavelength on a log scale simulated with sparameters for two different bias voltage. Four level pulse amplitude modulation pam4 has become the modulation format of choice to replace onoff keying ook for the 400 gbs short reach optical communications systems. The optical transfer function of a mach zehnder interferometer optical modulator is characterized by a raised cosine or sine transfer function. Machzehnder interferometer the transfer function for a lossless, imbalanced i.
Forward bias operation of silicon photonic mach zehnder. Applying a small sinusoidal signal to the travelingwave electrode of the smzm, the upper and lower arms of the smzm produce differential phase modulation effect. Versailles 433 185 121 siret 433 185 121 007 code ape 2651b n tva intra. As a device under test suitable to test the validity of the new rfscan method for the optical characterization of the spectral transfer function of devices both in amplitude and in phase, we will study the mach zehnder optical filter. Large signal analysis of machzehnder modulator intensity response in a linear dispersive fiber j m b oliveira1. An electrooptic modulator eom is an optical device in which a signalcontrolled element exhibiting an electrooptic effect is used to modulate a beam of light. Monolithically integrated machzehnder interferometer. The device is based on machzehnder interferometer made by titanium diffusion in lithium niobate substrate.
By varying the drive signals applied to the electrodes, i. Park har hotzvim, jerusalem, 91031, israel ulrich d. Here the thicknesses of the beamsplitters and the re. Instead of multiplying exponentials, their arguments are summed. Forward bias operation of silicon photonic mach zehnder modulators for rf applications rui lin chao,1,2 jin wei shi,1,3 aditya jain,1, takako hirokawa,1,4 akhilesh s.
Bbs4 protocol by qpsk modulation using dualelectrode mach. Osa linearized segmentation method for measuring the. Introduction to ixblue machzehnder modulators bias. Analysis of modulator linearity consider a machzehnder modulator with two identical, nonideal phase shifting sections placed into its arms, driven in a pushpull configuration see fig. The input waveguide is split up into two waveguide interferometer arms. How to simulate dual drive mach zehnder modulator in matlab. The modulation may be imposed on the phase, frequency, amplitude, or polarization of the beam. This is a particular issue in siliconphotonics systems due to high power density, where high temperature variation is inevitable. Machzehnder interferometer now assume that two 5050 beam splitters are in series, such that the outputs of one beam splitter are the inputs of the other beam splitter. We utilize various techniques to characterize the residual phase modulation of a waveguidebased mach zehnder electrooptical.
A machzehnder modulator is used to control the amplitude of an optical wave which is given to it. If a voltage is applied across one of the arms, a phase shift is induced for the wave passing through that arm. If we apply data and inverted data, the optical output will be chirp free, if we change the amplitudes of the driving signals the chirp can be adjusted. Svarny t advances in robotics, mechatronics and circuits. Phase angle in order to minimize the unwanted harmonics and inter modulation components at the output of the mach zehnder modulator. Introduction to machzehnder modulator bias controllers laser. On the performance of a linearized dual parallel mach. We present 3 different silicon photonic machzehnder modulator. This work covers indium phosphide inp segmented machzehnder modulators.
Waveguide linbo3 intensity modulators are mach zehnder type interferometers. Design, fabrication and analysis of a machzehnder interferometer user. Iq or intensity mach zehnder supported modulation formats all, no dependency max. Performance analysis of rof link using machzehnder. Pdf linearity characterization of a dualparallel silicon. Diagram of a simple machzehnder interferometer, ignoring the thickness of the beamsplitters. The linearity is comparable to a reference lithium niobate machzehnder interferometer modulator operating at quadrature and over an order of magnitude greater than silicon ring modulators based. An optical iq modulator iqm including two parallel machzehnder modulators mzm1, mzm2 generates single sideband data signals. Errorfree transmission of 23 gbs ook is achieved with driving electronics of 7. Beam splitter inputoutput relations university of rochester. The immediate conclusion is that although the transfer function of the modulator is nonlinear cosine square, the harmonics content at the quadrature bias point. The optical wave enters from the input side and then splits equally into two arms.
When such a splitter is placed at the second position in a particular way, the green light beam going to screen 1 will be suffering zero phase shift because it suffers a reflection coming from the denser medium and going back into the denser medium. As a device under test suitable to test the validity of the new rfscan method for the optical characterization of the spectral transfer function of devices both in amplitude and in phase, we will study the. The operation of a mach zehnder interferometer is often used as an example in quantum mechanics because it shows a clear pathchoice problem. Phase angle in order to minimize the unwanted harmonics and inter modulation components at the output of the machzehnder modulator.
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