Modulation format conversion in future optical networks. Pdf enhanced selfphase modulation in tapered fibers. Due to ever increasing channel density in wdm systems the nonlinear optical effects in fibers become a limiting factor for the highspeed data transmission, which necessitates determination of such important characteristic as the coefficient of optical nonlinearity. In this paper, we report on a fiber laser with modulation regimes achieved by. Compared with the currently welldeployed broadband access technologies of adsl asymmetric digital subscriber line and cable modems, optical broadband access with fiber totheusers home will cater for much higher speed access for new services. Selfphase modulation in optical fiber communications.
Fiber optical communication lecture 5, slide 16 crossphase modulation, fourwave mixing when more than one wavelength is present, we can often consider these as separate waves interact via crossphase modulation xpm and fourwave mixing fwm consider the case with two wavelengths a a expi. Rp photonics encyclopedia selfphase modulation, spm, kerr. Nonlinear fiber optics deals with various nonlinear phenomena in optical fibers, including wave propagation, groupvelocity dispersion, selfphase modulation, optical pulse compression, crossphase modulation, stimulated raman scattering and brillouin scattering, and parametric processes. Methods for estimation of optical fiber nonlinearity using self phase modulation effect. Detailed numerical modeling shows that self phase modulation dominates the spectral broadening, self steepening. Assumes lorentzian line shape, selfcoherence function. The project file the project file qam transmitter and receiver. The optical signal has been degraded by 800 km length of transmission and has passed through the regeneration section.
The simulated results show that the interaction of anomalous group velocity dispersion with self phase modulation gives improved. Optical transmission system simulation for analysis of self. The term selfphase modulation is occasionally used outside the context of the kerr effect, when other effects cause intensitydependent phase changes. The jenoptik integrated optical phase modulator is a fiber coupled electro optical light modulator. 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. Conclusion the effect of self phase modulation on optical fiber is reported in this paper. This was because optical detectors are only sensitive to amplitude optical power and not to phase, and manipulating the phase of optical signals at high frequencies is difficult. Self phase modulation refractive index depends on optical intensity as kerr e ect nw.
Selfphase modulation in optical fibers, proceedings of. We demonstrated 10gbs nrz signal regeneration based on self phase modulation spm in a single highly nonlinear fiber hnlf. Advanced optical modulation formats and their comparison. Rp photonics encyclopedia phase modulators, optical. All fiber picosecond optical pulse generator based on self phase modulation effect and spectral filtering using narrowband fbg the european conference on lasers and electrooptics. Based on the self phase modulation in dispersion flattened highly nonlinear photonic crystal fiber and followed spectral filtering, simultaneous 1to8 all optical wavelength multicasting returntozero rz. Self phase modulation spm occuring at moderate power levels in singlemode fibers has important implications on longrange optical fiber 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. Optical transmission system simulation for analysis of. The core diameter and the pitch of the fiber are 2.
Methods for estimation of optical fiber nonlinearity using selfphase modulation effect. We propose and demonstrate a new approach to implement a wavelengthtunable ultrafast fiber laser source suitable for multiphoton microscopy. Based on the selfphase modulation in dispersion flattened highly nonlinear photonic crystal fiber and followed spectral filtering, simultaneous 1to8 alloptical wavelength multicasting returntozero rz. Where n index of refraction of medium wave travels. Graph for quality factor versus dispersionwith self phase modulation spm and without self phase modulation spm. The phase change is converted into an intensity change using interferometric schemes machzehnder, michelson, fabryperot or sagnac forms. Sep 19, 2005 investigation of self phase modulation based optical regeneration in single mode as2se3 chalcogenide glass fiber. The implications of various nonlinear effects on the performance of lightwave systems are emphasized. Srs is useful for frequencyconversion applications 5. Our recent experimental demonstration of the coherent transmission system, with a high symbol rate using up to 110gbaud pdmqpsk signals on a 100 ghz grid, reported in 2014, is still among the top records. Selfphase modulation spm crossphase modulation xpm fourwave mixing fwm origin of nonlinear e. Crossphase modulation can be used as a technique for adding information to a light stream by modifying the phase of a coherent optical beam with another beam through interactions in an appropriate nonlinear medium. Broadband optical access and fiber tothehome ftth will provide the ultimate broadband service capabilities. Johannisson, signal statistics in fiberoptical channels with dual polarization and selfphase modulation, submitted.
An important phenomenon where optical phase manifests itself is total internal reflection. In our work, the single channel bandwidth is suppressed by using the supernyquist. Modulation in optical fiber lasers using polarization. With jenoptik integrated optical phase modulators, you can influence the phase of light in particularly high modulation frequencies up to the gigahertz range. With the goal of reducing the impact of nonlinearities, the purpose of this research was to identify a set of cpm signals best suited for high speed. Compensation of self phase modulation by anomalous. Selfphase modulation spm occuring at moderate power levels in singlemode fibers has important implications on longrange optical fiber transmission. Phase modulation weichih wang southern taiwan university of technology. The fiber graded index generates a periodicity in the beam diameter. A tutorial introduction to optical modulation techniques. Limitating and beneficial aspects of this fiber nonlinearity on future highbitrate optical communication systems will be discussed, including soliton propagation, powerdependent transmission bandwidth variations and modulational instability.
If the input optical power increases after certain threshold level, it contributes to. Depending on the parameter of a light beam which is manipulated, modulators may be categorized into amplitude modulators, phase modulators, polarization modulators etc. Unless the optical fiber is in an ultrastable condition, that is, neither temperature fluctuations nor vibrations occur in the environment, phase will constantly fluctuate due to temperature and stress induced changes in refractive index and length of the optical fiber. Basic structure of an optical fiber an optical fiber is a flexible, transparent fiber made by glass silica or plastic to a diameter slightly thicker than that of a human hair. Cross phase modulation can be used as a technique for adding information to a light stream by modifying the phase of a coherent optical beam with another beam through interactions in an appropriate nonlinear medium. Continuous phase modulation cpm is a format in which data is encoded in the phase, while the amplitude is constant throughout all transmission even during transitions between symbols. During the regeneration, the significant improvement of ber 1015 to ber 1018 is recorded.
Selfphase modulation spm leads only to a phase shift in the time domain. Fiber nonlinearity includes stimulated brillouin scattering sbs, stimulated raman scattering srs, four wave mixing fwm, self phase modulation spm and cross phase modulation xpm. Self phase modulation experienced by a triangular pulse in. Optical fiber modulation techniques are therefore required to either encode information or extract information from the fiber guided beam. 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.
The propagation of an intensitymodulated signal in an optical fiber is numerically analyzed, taking selfphase modulation, groupvelocity dispersion, and 2ndorder groupvelocity dispersion into. 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. Osa compression of optical pulses chirped by selfphase. Twophoton absorption and selfphase modulation in silicon. Those light waves may be sent through a transparent medium as a laser beam, or contained within a fiber optic cable. Selfphase modulation enabled, wavelengthtunable ultrafast fiber laser sources. In this paper the effect of positive and negative group velocity dispersion is shown on self phase modulation. The use of self phase modulation in a singlemode fiber to chirp an optical pulse, which is then compressed with a gratingpair compressor, has been shown to be a practical technique for the production of optical pulses at least as short as 30 fsec. Self phase modulation experienced by a triangular pulse in a. Selfphase modulation in optical fibers, proceedings of spie. Advanced optical modulation formats and their comparison in. Jul 11, 2016 selfphase modulation enabled, wavelengthtunable ultrafast fiber laser sources. Coded modulation techniques in fiberoptical communications.
Spm forms the basis for the fiber and grating pulse compressor,3. Pdf improvement of data rate in optical system using. We employ fiber optic nonlinearities to broaden a narrowband optical spectrum generated by an yb fiber laser system and then use optical bandpass filters to select the leftmost or rightmost spectral lobes from the broadened spectrum. We propose and demonstrate a new approach to implement a wavelengthtunable ultrafast fiber. Modulated optical fiber laser sources have proven useful in applications ranging from fiber communications systems to optical fiber sensors. The physical mechanism behind spm is gain saturation, which leads to intensitydependent changes in the refractive index in response to variations in the carrier density. An optical modulator is a device which is used to modulate a beam of light. Program listings of the initialization file 98 references 100 4. This technique is applied to fiber optic communications. Oct 10, 2010 a wavelength converter based on the self phase modulation spm effect in highly nonlinear microstructure fibers mfs is proposed.
There are, for example, sensors dependent on relative phase shift upon reflection from an interface. We demonstrated 10gbs nrz signal regeneration based on selfphase modulation spm in a single highly nonlinear fiber hnlf. Rp photonics encyclopedia selfphase modulation, spm. Optical modulation a tutorial introduction to optical modulation techniques by gary breed editorial director t his article introduces the subject of optical modulation, the process of applying information to a light wave. This lesson demonstrates the basic effects of selfphase modulation spm on pulse propagation.
Intensity dependence leads to nonlinear phase shift f nlt2pln 2itl. 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 be a practical technique for the production of optical pulses at least as short as 30 fsec. Optical fiber is a dielectric waveguide and ideally has a cylindrical shape. On the other hand selfphase modulation can be the base for the realization of novel nonlinear optical fiber devices.
Self phase modulation experienced by a triangular pulse in a nonlinear optical fiber experiments done at the laboratoire interdisciplinaire carnot. The propagation of an intensitymodulated signal in an optical fiber is numerically analyzed, taking self phase modulation, groupvelocity dispersion, and 2ndorder groupvelocity dispersion into. Selfphase modulation and optical pulse compression. The spatial profile and the spectral distribution of a pulse propagating in a parabolic gradedindex optical fiber are derived. Amplification of ultrashort optical pulses in semiconductor laser amplifiers is shown to result in considerable spectral broadening and distortion as a result of the nonlinear phenomenon of self phase modulation spm. In this paper, we focus on how advanced optical modulation formats enable highcapacity optically routed transport networks. All optical multicasting of performing data routing from single node to multiple destinations in the optical domain is promising for next generation ultrahighpeed photonic networks. Selfphase modulation enabled, wavelengthtunable ultrafast. Osa selfphase modulation enabled, wavelengthtunable. Nonlinear transmission is investigated in a hydrogenated amorphous silicon optical fiber extending into the midinfrared region.
Modulation format conversion in future optical networks javier cano adalid master thesis supervisors. Sep 26, 2007 modulated optical fiber laser sources have proven useful in applications ranging from fiber communications systems to optical fiber sensors. Enhanced self phase modulation in tapered fibers p. These effects are seen from the eye diagrams drawn for the different values ofdispersion. We investigate the feasibility of alloptical regeneration based on selfphase modulation in single mode as2se3 chalcogenide fiber. A wavelength converter based on the self phase modulation spm effect in highly nonlinear microstructure fibers mfs is proposed. As with many other coherent light sources, fiber lasers can easily be modulated by means of electrooptical devices. Numerical results are presented for the achievable compression and compressed. If the input optical power increases after certain threshold level, it contributes to intensity of special broadening. Simulation and analysis of self phase modulation fiber non. In that case, the phase modulation often needs to be strong in order to obtain a large number of optical sidebands. Fourwave mixing and selfphase modulation for switching, pulseforming and wavelength conversion applications.
Limitating and beneficial aspects of this fiber nonlinearity on future highbitrate optical communication systems will be discussed, including soliton propagation, powerdependent transmission. Alloptical multicasting of performing data routing from single node to multiple destinations in the optical domain is promising for next generation ultrahighpeed photonic networks. Nonlinear fiber optics deals with various nonlinear phenomena in optical fibers, including wave propagation, groupvelocity dispersion, self phase modulation, optical pulse compression, cross phase modulation, stimulated raman scattering and brillouin scattering, and parametric processes. Methods for estimation of optical fiber nonlinearity. Osa selffocusing and selfphase modulation in a parabolic. Ohtsu, senior member, ieee abstract the width of an optical frequency comb ofc was increased to 30 thz by using selfphase modulation spm in an optical. As with many other coherent light sources, fiber lasers can easily be modulated by means of electro optical devices.
Analysis of spm, xpm, and fwm in fiber optic communication. In order to make smf28 more competitive for 40gbs optical transmission, optical phase modulation may be used, such as dpsk. Selfphase modulation and spectral broadening of optical. Investigation of selfphase modulation based optical regeneration in single mode as2se3 chalcogenide glass fiber. Modulation scheme for fiber optical channel with nonlinear phase noise, in proceedings of ieee global communications conference, dec. Wavelength conversion technique based on self phase. Nonlinear photonic crystal fibers highly nonlinear pcf for 800 nm pump lasers applications supercontinuum generation for frequency metrology, spectroscopy, or optical coherence tomography using ti.
Interference when two or more optical waves are present simultaneously in the same region of space, the total wave function is the sum of the individual wave functions. If the input optical power increases after certain threshold level, it contributes to intensity of special broadening exponentially. Being aware of the sophisticated modulation and detection schemes and algorithms employed in rf engineering, we first want to put the word badvancedused in conjunction with optical modulation formats in proper context. The remaining sections are dedicated to other modulation formats, including squarewave phase modulation swm, optical duobinary, and alternate mark inversion ami. The beam may be carried over free space, or propagated through an optical waveguide optical fibre. We investigate the feasibility of all optical regeneration based on self phase modulation in single mode as2se3 chalcogenide fiber. Just as in radio, optical systems started out with amplitude modulation, which is known as onoffkeying or ook. Pulse chirping pulse spectral broadening the effects spm of are described by 1. Measurands then induce a change in the optical phase, frequency or polarization state of the beam. It consists of a core made up of a dielectric material which is surrounded by a cladding made up of a dielectric material of. Nonlinear effects in the optical fiber occurring due to nonlinear refractive index are selfphase modulation spm, crossphase modulation xpm, fourwave mixing fwm. This technique is applied to fiber optic communications xpm is among the most commonly used techniques for quantum nondemolition measurements. Investigation of selfphase modulation based optical.