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| 4. |
- Kylemark, Per, 1976, et al.
(författare)
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Noise statistics of fiber optical parametric amplifiers
- 2006
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Ingår i: OFC/NFOEC 2006. 2006 Optical Fiber Communication Conference and National Fiber Optic Engineers Conference. ; , s. OWT5-
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Konferensbidrag (refereegranskat)abstract
- We show both theoretically and experimentally that the probability density function of a signal amplified by parametric amplifiers with pump excess noise is non-Gaussian and asymmetric. This impacts the relationship between the noise figure and the bit-error rate
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| 5. |
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| 6. |
- Bogris, Adonis, et al.
(författare)
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Noise Characteristics of Dual-Pump Fiber-Optic Parametric Amplifiers
- 2005
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Ingår i: Journal of Lightwave Technology. ; 23:9, s. 2788 – 2795-
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Tidskriftsartikel (refereegranskat)abstract
- The noise figure (NF) properties of an undepleted and lossless dual-pump fiber-optic parametric amplifier (FOPA) are theoretically and numerically investigated. The theoretical study takes into account the noise characteristics of the two pump waves that are considered to have parallel polarization states for gain maximization. It is shown that noisy pump waves degrade the amplifier's NF, especially when the amplifier is operating at high gain values and when the input signal is high. The theoretical observations are validated by Monte Carlo numerical simulations, and the agreement between them is excellent. Finally, a comparative study concerning the noise characteristics of dual-pump and single-pump FOPAs is performed.
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| 7. |
- Kylemark, Per, 1976, et al.
(författare)
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DM solitons in long-haul DWDM systems at 40 Gb/s with nonlinear interactions and PMD
- 2003
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Ingår i: IEEE Photonics Technology Letters. ; 15:10, s. 1372-4
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Tidskriftsartikel (refereegranskat)abstract
- The authors investigate for the first time how polarization mode dispersion and nonlinear interactions affect dense wavelength division multiplexing dispersion management-soliton long-haul transmission using Monte Carlo simulations. They also discuss how the system is affected by an increasing number of wavelength channels
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| 8. |
- Kylemark, Per, 1976, et al.
(författare)
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Gain and wavelength dependence of the noise-figure in fiber optical parametric amplification
- 2006
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Ingår i: IEEE Photonics Technology Letters. ; 18:11, s. 1255-7
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Tidskriftsartikel (refereegranskat)abstract
- We measure, for the first time, the wavelength resolved electrical noise figure (NF) of a fiber-optical parametric amplifier and find excellent agreement with theoretical predictions. We furthermore measure the NF in the exponential gain regime at high gain and quantify the gain dependence of the NF as well as its spectral dependence
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| 9. |
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| 10. |
- Kylemark, Per, 1976, et al.
(författare)
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Impact of Phase Modulation and Filter Characteristics on Dual-Pumped Fiber-Optical Parametric Amplification
- 2006
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 18:2, s. 439 - 441
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Tidskriftsartikel (refereegranskat)abstract
- We have derived theory predicting the impact phase modulation has on dual-pumped parametric amplifiers which includes also the effect of pump power fluctuations. The theory shows that gain perturbations due to perturbations in the pump frequencies can be significantly reduced by operating the two pumps out of phase. Furthermore, filtering the phase-modulated pumps can introduce detrimental gain variations and we propose the use of flat-top filter characteristics in order to reduce the filter bandwidths around the pump without causing too much gain-variations on the amplified signal. We also investigate the effect of detuned optical filters.
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| 11. |
- Kylemark, Per, 1976, et al.
(författare)
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Impact of Pump Phase-Modulation on the Bit-Error Rate in Fiber-Optical Parametric-Amplifier-Based Systems
- 2007
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 19:2, s. 79-81
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Tidskriftsartikel (refereegranskat)abstract
- Pump phase-modulation is often needed to suppress stimulated Brillouin scattering in fiber-optical parametric amplifiers. We show that while this causes a gain variation with a corresponding Q-value penalty, the actual bit-error-rate degradation is not always significant. The findings are supported by experimental studies.
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| 12. |
- Kylemark, Per, 1976
(författare)
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Noise and Saturation Properties of Fiber Optical
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fiber Optical Parametric Amplifiers (FOPAs) are based on a highly efficient Four-wave Mixing process in highly nonlinearfibers and have gained a lot of interest since it was shown that ahigh gain can be obtained. They are multi-functional devices thatare not only limited to amplifying signals, but their wide range ofapplicability also include wavelength conversion, pulse-generation,optical sampling and also regeneration at very high bit-rates. Theforemost property that makes this amplifier unique is its very fastresponse time, which make the signal gain respond to any change inpump power almost instantaneously.The FOPA was long thought of as an ideal amplifier in terms of noiseperformance. We show, however, that the noise around the pump itselfis transferred to the signal. The fast response time makes thissource of noise particularly large compared with other amplifiersexhibiting similar properties. This leads to stringent requirementson the laser. In this thesis we have developed a theory for thenoise figure of FOPAs, both in single-pumped and dual-pumpedimplementations and show very good agreement with experimentalmeasurements.Furthermore, in order to launch the pump powers necessary for highgain, the pump sources need to be phase-modulated in order to reducethe effects of stimulated Brillouin scattering. This may introduceintensity fluctuations on to the signal and may therefore affect theamplifiers performance. We quantify this effects and also derivetheory of how it affects the bit-error rate (BER) in digital data.It is shown that its effect on the BER is much lower then previouslyexpected.Also, optical signal regeneration is based on a nonlinearrelationship between the input and output optical power. FOPAsexhibit such a relationship when operated in the saturated gainregime. We simplify previous gain saturation theories and presentexperimental measurements proving our theory. A simplifiedexpression is useful in the development of regenerators and in thedesign of multi-wavelength amplification, where cross gainsaturation may affect the amplifier performance.
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| 13. |
- Kylemark, Per, 1976, et al.
(författare)
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Noise in dual-pumped fiber-optical parametric amplifiers: Theory and experiments
- 2007
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 25:9, s. 2837-2846
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Tidskriftsartikel (refereegranskat)abstract
- The noise figure (NF) of a dual-pumped parametric amplifier with copolarized pumps is quantified for the first time to our knowledge. It is shown that the NF is increased by the noise on the pump sources, in agreement with theory, and that it gives a uniform NF degradation due to a uniform gain spectrum. The magnitude of the NF degradation increases with increasing input-signal power. Various aspects of the NF are studied, such as the effects of three idlers generated by the four-sideband interaction, and Raman-induced losses and excess noise caused by the population of thermal phonons. It is shown that the use of unequal pump powers only affects the low-power NIT to a minimal degree. Also, the gain dependence of the NF is studied, as are the wavelength and signal power dependences of the NE It is shown that at high gain, the NF saturates even when pump noise is an issue. Also, unequal pump powers with fixed gain have a minor impact on the noise performance of the amplifier. Theory and experiments agree well with each other.
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| 14. |
- Kylemark, Per, 1976, et al.
(författare)
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Noise in Orthogonally Pumped Fiber-Optical Parametric Amplifiers
- 2007
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 19:2, s. 88-90
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Tidskriftsartikel (refereegranskat)abstract
- The noise figure (NF) of a fiber-optical parametric amplifier, driven by pumps with orthogonal polarizations, is quantified experimentally. It is shown that this amplifier has a signal- polarization -dependent gain, with a corresponding polarization-dependent NF. The polarization dependence of the NF is particularly large when higher input-signal powers are amplified, in which case pump-induced noise dominates. At lower input-signal powers, the NF is less dependent on the input polarization, but increases closer to the lower-frequency pump.
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| 15. |
- Kylemark, Per, 1976, et al.
(författare)
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Noise statistics in fiber optical parametric amplifiers
- 2007
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Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 25:2, s. 612-620
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we show both theoretically and experimentally that the probability density function of the intensity of an amplified signal by parametric amplifiers subject to a pump with excess noise is highly asymmetric. This is due to the nonlinear relationship between the optical pump power and the parametric gain. Because of this, the relationship between the noise figure (NF) and the bit error rate (BER) is modified, compared with that predicted by the chi(2) theory, which is an effect that is notable at large NFs and low BERs. The difference in predicted BER can be of several orders of magnitudes between the correct theory and the chi(2) approximation in single-stage parametric amplifiers. We also show that in the limit of many cascaded parametric amplifiers, the statistics of the noise of an amplified optical signal approaches chi(2). Furthermore, the BER of a parametric amplifier is generally lower compared with erbium-doped fiber amplifiers for the same NF values if we assume quantum-limited amplification.
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| 16. |
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| 17. |
- Kylemark, Per, 1976, et al.
(författare)
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Penalties due to the combined effects of amplitude noise and timing-jitter with application to a 40 Gbit/s DM-soliton system
- 2005
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Ingår i: Optical Fiber Technology. ; 11:1, s. 20-33
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Tidskriftsartikel (refereegranskat)abstract
- We derive equations for penalties introduced by the combined effects of timing-jitter and amplitude noise in a transmission link. We then apply the results on a DM-soliton system operating at 40 Gbit/s, where Gordon-Haus-jitter is important at large distances. We predict, using the theory, the maximum transmission distance for various systems. Finally, we compare the theory with numerical simulations and find a good agreement between them.
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| 18. |
- Kylemark, Per, 1976, et al.
(författare)
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Properties of pump-induced noise in fiber optic parametric amplifiers
- 2006
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Ingår i: Optics InfoBase Conference Papers. - Washington, D.C. : OSA. - 2162-2701.
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Konferensbidrag (refereegranskat)abstract
- We investigate the pump-induced noise in fiberoptic parametric amplifiers theoretically and experimentally, and find unique features with respect to wavelength dependence and noise statistics.
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| 19. |
- Kylemark, Per, 1976, et al.
(författare)
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Semi-analytic saturation theory of fiber optical parametric amplifiers
- 2006
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Ingår i: Journal of Lightwave Technology. ; 24:9, s. 3471-9
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Tidskriftsartikel (refereegranskat)abstract
- A semi-analytical theory for the gain saturation of parametric amplifiers is presented. The theory is both simple and intuitive, it is compared with experiments on a parametric amplifier, and a very good agreement is found. Furthermore, using theoretical results, a method to obtain saturation characteristics for parametric amplifiers that have features not easily reproduced by theory is presented. The obtained method finds saturation characteristics in a few steps, providing that the gain studied is above 15 dB, where the approximations upon which our simple expression is based are strictly valid. An exact solution of the gain saturation when the pump power is totally converted is also presented and compared with the simplified expression using previously obtained theoretical results
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