Theory of selfphase modulation and spectral broadening. Simulation and analysis of self phase modulation fiber non linearity narender kumar sihval m. Distinguishing thermal lens effect from electronic third. The optical kerr effect manifests itself temporally as selfphase modulation, a selfinduced phase and frequencyshift of a pulse of light as it travels through a medium. Spectral broadening induced by selfphase modulation wolfram. We demonstrate the self phase modulation spm of a singlecycle thz pulse in a semiconductor, using bulk ngaas as a model system. Selfphase modulation is an important effect in optical systems that use short, intense pulses of light, such as lasers and optical fiber communications systems6. Highfield nonlinear optical response and phase control in. Coherent control of plasma dynamics nature communications. We study nonlinear phenomena in optical fibers and waveguides for a variety of applications including optical communications. Phase modulation is similar to frequency modulation and is an important technique in digital communication systems. Effects of nonlinear chirp on the selfphase modulation of.
Phase modulation pm is a modulation pattern for conditioning communication signals for transmission. Selfphase modulation is an important effect in optical systems that use short, intense pulses of light, such as lasers and optical fiber communications systems. The resulting wave equation is modified to include corrections to self phase modulation due to higherorder spatial and temporal derivatives. Senior project manager how is senior project manager. Split step fourier method file exchange matlab central. Simulation and analysis of self phase modulation fiber non. Amplification of ultrashort pulses in optical fibers can be degraded by the nonlinear phenomenon of selfphase modulation spm, resulting in. We demonstrate the selfphase modulation spm of a singlecycle thz pulse in a semiconductor, using bulk ngaas as a model. The information signal instead of being sent directly, is sent over a carrier signal. Deepa ventikesh at iit madras in chennai, india for two weeks in december 2019.
Methods for estimation of optical fiber nonlinearity using selfphase modulation effect article pdf available in latvian journal of physics and technical sciences 486. Both effects lead to a phase alteration of the pulses and are frequently called carrierinduced phase modulation cip. Intracavity selfphase modulation is also observed in the regenerative amplifi cation of weak input pulses from c. Conclusion the effect of self phase modulation on optical fiber is reported in this paper. Communications toolbox provides modulators and demodulators for these phase modulation techniques. Phase shift, frequency shift, pulse propagation in the presence of non. This nonlinearity manifests as frequency mixing, selfrefraction and selfphase modulation as light traverses through the material. An increase in dispersion reduces cross phase modulation. The use of selfphase modulation in a singlemode fiber to chirp an optical pulse, which is then compressed with a gratingpair compressor, has been shown to. Tgs can be used to build self animating procedural abstract animation effects. Modeling of nonlinear ultrashort optical pulse propagation. Modulation technique for software defined radio application.
Rp photonics encyclopedia selfphase modulation, spm. Methods for estimation of optical fiber nonlinearity using. Self phase modulation spm and the group velocity dispersion gvd. Selfphase modulation of a singlecycle terahertz pulse by nonlinear. This video discusses basics of phase modulation which includes definition of phase modulation and also phase modulated waveform. Nonlinear characteristics include selfphase modulation spm, crossphase modulation xpm, fourwave mixing fwm, stimulated raman scattering srs,stimulated brillouin scattering sbs1,2,3 ii. Theory the intracavity self phase modulation and the grating pair pulse compression are described. Output parameters contain the output results, complete data table and animation. The self phase modulation and modulation instability of an optical probe electromagnetic field in multiple quantum well systems under electromagnetica. Agrawal received the osas max born award during the award ceremony held on september 16, 2019 at frontiers in optics conference in washington, dc. An ultrashort pulse of light, when travelling in a medium, will induce a varying. This lesson demonstrates the basic effects of selfphase modulation spm on pulse propagation. Theoretical analysis of pulse shaping of selfphase. For the example above, using a tg to modulate the displacement angle over time lead to a more interesting effect for a static effected output image.
It faces nonlinearities such as self phase modulation, cross phase modulation and fourwave mixing, which affects the spectral efficiency. Whether it is spm, xpm or any other nonlinear behavior, all are attributed to nonlinear polarization of a material with respect. Self phase modulation is an important effect in optical systems that use short, intense pulses of light, such as lasers and optical fiber communications systems. In this article, we analytically investigate the spectral broadening by selfphase modulation of strongly chirped optical pulses. We have studied self action effects self focusing and self phase modulation and stimulated raman scattering in an yb. This system utilizes a combination of an allsolidstate modelocked sumfrequency generation sfg laser 1. Selfphase modulation and optical pulse compression.
Self phase modulation how is self phase modulation. It encodes a message signal as variations in the instantaneous phase of a carrier wave. Numerical investigations of self and crossphase modulation effects. Self phase modulation and cross phase modulation in. Now the older disciplines of detection theory and coding theory have been generalized and applied to the point where it is hard to tell where these end and the theories of signal design and modulation begin. Graph for quality factor versus dispersion with self phase modulation spm and without self phase modulation spm v. However, optical fibers induce nonlinear effects, especially self phase modulation spm. Fiber nonlinearities such as self phase modulation spm and cross phase modulation xpm have drawn significant consideration 2. Compression of optical pulses chirped by selfphase modulation. The self steepening, well described by adiabatic following, results from i an intensitydependent pulse velocity, ii selfphase modulation combined with strong groupvelocity dispersion. Phase modulation is a linear baseband modulation technique in which the message modulates the phase of a constant amplitude signal. The simulation has been done with the software rp fiber power. Pulse chirping pulse spectral broadening the effects spm of are described by 1.
Nonlinear effects in optical fibers originate from the intensity dependence of the refractive index and stimulated inelastic scattering. For the relevant initial conditions we find that kerr self phase modulation is the primary nonlinear phenomenon, followed by self focusing and then sixphoton absorption and self steepening. Analysis of effect of self phase modulation in wavelength. Plasmainduced selfphase and crossphase modulation of. The effects of spminduced chirping and spectral broadening are related 1. The effect of self phase modulation in chirpedpulse amplification is investigated. Senior project manager and quantity surveyor lee lloyd has acted as employers agent, contract administrator and fund surveyor while alistair smith is a graduate building.
Selfphase modulation selfphase modulation spm is a nonlinear optical effect of lightmatter interaction4,5. Spm arises because the refractive index of the fibre has. Fwm is the prominent nonlinearity faced by apdcdm system. It has also been reported for nonlinear sound waves propagating in biological thin films, where the phase modulation results from varying elastic properties of the lipid films.
Single channel systems are subject to self phase modulation spm. Rudiger paschotta, rp photonics consulting gmbh version. Intracavity self phase modulation the self phase modulation of a laser pulse is due to temporal refractive index changes caused by. Beats in the spectrum of each filament demonstrate the coherent nature of the process. Self phase modulation spm and cross phase modulation xpm, or cpm are two of the most important nonlinear effects in optical telecommunications. Angle modulation is the process in which the frequency or the phase of the carrier varies according to the message signal. Theory of selfphase modulation and spectral broadening springerlink. Tgs can also add dynamic movement of effect modulation to dualmode paint presets that use use msg as their dual op. Oct 09, 2016 in laymans terms, modulation is a technique where one changes one or more parameters of a carrier signal to carry the information. Optical transmission system simulation for analysis of self. Definition of an fm signal for a baseband signal, xt. Coded modulation techniques in fiberoptical communications. The other type of modulation in continuouswave modulation is the angle modulation.
Phase modulation, pm is sometimes used for analogue transmission, but it has become the basis for modulation schemes used for carrying data. The incoming analog signal is modulated using phase shift keying psk type modulation. The observations of spatial self phase modulation and the associated multiple di. However, initiating modelocking will also become more difficult, with techniques such as pump power modulation or external seeding quickly becoming necessary. Impact of initial pulse characteristics on the mitigation of selfphase. The numerical simulation which takes into account chromatic dispersion, spm, selfsteepening and stimulated raman scattering has been done with the rp fiber power software. Graph for quality factor versus dispersionwith self phase modulation spm and without self phase modulation spm. Self phase modulation spm and cross phase modulation xpm are two of such nonlinearities in silicon studied in quite detail in literature and used in applications pertaining to optical communications and computing.
Fm signals have the same peak frequency deviation, then when mt is a sinusoidal signal set such that the pm and note. Her prior experience includes over 12 years in photonics research and development, including her nicta role as a principal researcher. Citeseerx licensed under creative commons attribution cc. These effects are seen from the eye diagrams drawn for the different values ofdispersion. Relations are given that allow an optimum power level of the optical signal to be chosen as a function of the modulation.
The induces self phase modulation is phase modulation can be used as a light switch or fuse. The numerical simulation which takes into account chromatic dispersion, spm, self steepening and stimulated raman scattering has been done with the rp fiber power software. Phase modulation is also the basis of a form of modulation known as quadrature amplitude modulation, where both phase and amplitude are varied. The theory presented is generally applicable to self phase modulation and grating pair pulse compression. Nov 17, 2017 this video discusses basics of phase modulation which includes definition of phase modulation and also phase modulated waveform. This is further divided into frequency and phase modulation. Rz and nrz modulation schemes are used to evaluate the performance parameters of apdcdm system. Simple guidelines to predict selfphase modulation patterns arxiv. Selfphase modulation spm is a nonlinear optical effect of lightmatter interaction. This process, along with dispersion, can produce optical solitons. Our group works on different aspects of the fiber nonlinear effects known as self phase modulation, cross phase modulation, fourwave mixing, stimulated raman scattering, and stimulated brillouin scattering. The temporal action of a medium whose index of refraction increases with increasing optical intensity on timevarying optical signals or pulses, whereby the.
Effect of selfphase modulation on the pulse bandwidth. Effect of selfphase modulation and crossphase modulation. Theoretical analysis of pulse shaping of selfphase modulated. The results demonstrate that self focusing in combination with thermal lensing may significantly limit the chirped pulse energy in. Here, we reported the performance of silicon on insulator soi phase modulator. Selfphase modulation spm is one of those very fascinating effects. For a single tone message, at one frequency, it is not possible to tell. To see the spm induced spectral broadening let us introduce the quantity. Self phase modulation selfphase modulation is due to the intensity dependent refractive index p and a are respective the beam power and crosssectional area. The spm arises from the heating of free electrons in the electric field of the thz pulse, leading to an ultrafast reduction of the plasma frequency, and hence to a strong modification of the thzrange dielectric function of the material. The phase modulator devices have been integrated in the silicononinsulator soi waveguide by using the pin diode structure. Agrawal research group nonlinear photonics and optical.
Figure 4 shows the spectra for an unchirped gaussian input pulse for several values of the maximum phase shift. I have some bore hole data but i have no such software which help me to draw that graph easily. Because of the smaller interaction time between pulses. In particular, this is the case in semiconductor lasers and semiconductor optical amplifiers, where a high signal intensity can reduce the carrier densities, which in turn lead to a modification of the refractive index and thus the phase change. Phase shoft keying, psk is widely used for data communication. Phase modulation basics, definition and waveform hd. This demonstrates that spm can increase or decrease the bandwidth, depending on the pulse. Amplification of ultrashort optical pulses in soa produces considerable spectral broadening and distortion due to the nonlinear phenomenon of selfphase modulation. But phase modulation seems to be in a different categorypm radio is by no means a common term. Self phase modulation in an optical system is said to. For instance, the 4nm bandpass filters in the animation shown are separated by 10 nm, which is a moderate offset.
These effects are seen from the eye diagrams drawn for the different values of dispersion. Digital modulation techniques, java applets and animations. Self phase modulation refers to the phenomenon in which a laser beam propagating in a medium interacts with the medium and imposes a phase modulation on itself. This nonlinear phenomenon, known as selfphase modulation, causes spectral broadening. The alteration of the phase leads to a change of the pulse spectrum. Analytical treatment of the self phase modulation of an ultrashort light pulse is extended beyond the slowly varying envelope approximation. Self phase modulation and cross phase modulation in nonlinear. Rp photonics encyclopedia selfphase modulation, spm, kerr. A numerical model is used to predict the effects of phase modulation on pulse recompression, and experimental results are presented that agree well with the calculations. Selfphase modulation article about selfphase modulation.
Nonlinear effects have been considered as being generally destructive for long haul fiber optic transmission system 1. Waveform of modulating signal message signal and carrier wave is. For example, raman forward scattering, envelope self modulation, relativistic self focusing and relativistic self phase modulation 29 and many. The term self phase modulation is occasionally used outside the context of the kerr effect, when other effects cause intensitydependent phase changes. The deterioration in the quality index is found to be due to nonlinear phenomena self phase modulation and cross phase modulation and noise of the optical amplifier. Effect of selfphase modulation on the pulse bandwidth dr. Selfphase modulation how is selfphase modulation abbreviated. Despite our emphasis on the events of the last ten years, we have included all the traditional topics of digital phase modulation. When an optical pulse travel through the fiber, an increase or. Dispersion effects can be minimized by utilizing periodic dispersion compensation dcf along. Pdf modulation technique for software defined radio application. Self phase modulation spm and cross phase modulation xpm are two of such nonlinearities in silicon studied in quite detail in literature and used in applications pertaining to optical communications and. I study how pulse to pulse phase coherence in a pulse train can survive superbroadening by extreme self phase modulation spm. Phase modulation is one of the two principal forms of angle modulation, together with frequency modulation.
The physical mechanism behind spm is gain saturation, which leads to intensitydependent changes of refractive index in response to variations in carrier density. Effect of quintic nonlinearity on selfphase modulation. Modulation scheme for fiber optical channel with nonlinear phase noise, in proceedings of ieee global communications conference, dec. Selfphase modulation is the nonlinear phase modulation of a beam, caused by its own. She has also worked for vpisystems, an optical systems simulation software company, as a senior optical engineer. Propagation of an ultrashort pulse in a fiber, where selfphase modulation is the dominant effect on the pulse within the first 30 mm of propagation distance. The electrical device performance is predicted by using the 2d semiconductor package silvaco cad software under dc operation. Digital phase modulation applications of communications. The research paper published by ijser journal is about optical transmission system simulation for analysis of self phase modulation. Solitons, its evolution and applications in high speed. We show that even moderate self phase modulation can significantly distort. Pm and digital modulation s p where 2 is the pkpk phase change in one symbol duration, t for digital signals the modulation index. Simulation and analysis of self phase modulation fiber non linearity narender kumar sihval.1171 625 708 75 480 137 133 1344 251 417 1169 73 1261 75 950 1269 1339 792 473 1200 1109 72 695 200 744 912 224 1314 1077 219 17 175 1528 310 1301 847 900 874 1024 684 697 1276 1391 660 192 503