Nonlinear Distortion Analysis of Directly Modulated ... - 연세대학교

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Normalize Frequency Response (dB)100-10-20(1)(1) Free-running(2) -5.5 GHz(3) -13.3 GHz(4) -20.2 GHz(5) -26 GHz(5)(4)(3)0 5 10 15 20Frequency (GHz)(2)(a)Normalize Frequency Response (dB)100-10-20(1)(5)(1) Free-running(2) -30.7 GHz(3) -34.2 GHz(4) -36.4 GHz(5) -37.0 GHz(4)(3)(2)0 5 10 15 20Frequency (GHz)(b)Figure 3.9 Normalized frequency response of the injection locked SL. (a) Upper boundary ofstable locking region cases (b) Lower boundary cases. Injection ratio is fixed at –8 dB.36
phenomena occur well. As the injection power increases, the relaxationoscillation frequency increases greatly, and the damping appears very well.However, in the fig. 3-4, first two injection cases do not follow this trend. Thereason is that these cases are so close to the upper boundary of stable lockingrange that the damping effects are weakened.Next, for verifying these phenomena, IMD2 suppression simulationaccording to the injection wavelength is also executed. The injection powerratio is also –8 dB and the detuning frequency is selected within the stablelocking range. Modulation frequency is 2.8 and 2.9 GHz and the modulationindex is 0.1. Fig. 3-10 (a) shows the IMD2 suppression and fig. 3-10 (b) showsthe modulation signal power changes according to the injection wavelength.IMD2 suppression is calculated by subtracting the IMD2 at injection lockingfrom the IMD2 at free-running. The modulation signal power degradationvalues are decided by subtracting the signal power at injection locking fromthe signal power at free-running. As explained before, the IMD2 suppressionnear upper stable locking region is due to the relaxation oscillation frequencyincrease and the IMD2 suppression near lower stable locking region is due tothe high damping. The modulation signal power changes are also equal to theexpectation. The closer the detuning frequency is near lower stable regionboundary, the more the modulation signal power is reduced. Therefore, whenthe modulation signal power is compensated to the free-running signal power,IMD2 suppression trend is changed. Fig. 3-11 is the compensated result. Asthe detuning frequency is near the lower stable region boundary, the IMD2suppression is reduced. The reason is frequency response changes according tothe injection wavelength, and the simulation results are well reflected these37
Page 1 and 2: Nonlinear Distortion Analysis of Di
Page 3 and 4: ________________ ________________ _
Page 5 and 6: IndexFigure Index ⋅⋅⋅⋅⋅
Page 7 and 8: Figure 3.11 Simulation results of I
Page 9 and 10: AbstractNonlinear Distortion Analys
Page 11 and 12: I. IntroductionIn the past, telecom
Page 13 and 14: solution for increasing the detunin
Page 15 and 16: [8, 9, 10]. This phenomenon occurs
Page 17 and 18: 0Optical Power (dBm)-10-20-30-40-50
Page 19 and 20: is the laser nonlinear transfer fun
Page 21 and 22: (3) Laser nonlinear transfer functi
Page 23: D11= τng2− 2( N00[(1 − 2εP)(
Page 26 and 27: f kn . The order of the IMP corresp
Page 28 and 29: 100-10Amplitude (dB)-20-30-40-50-60
Page 30 and 31: -20Amplitude (dB)-30-40-50-60-70thr
Page 32 and 33: locking to suppress nonlinear disto
Page 34 and 35: By using this system matrix, the sy
Page 36 and 37: Harmonic Power (dBm)0-10-20-7 dBc2
Page 38 and 39: these suppression values are depend
Page 40 and 41: oscillation [21]. This will result
Page 42 and 43: 20Detuning Frequency (GHz)0-20-40-6
Page 44 and 45: nonlinear phenomena simulation shou
Page 48 and 49: effects.Finally, for verifying the
Page 50 and 51: IMD2 Suppression (dB)15141312111098
Page 52 and 53: -20-30-40-0-60-70-802.70 2.75 .80 2
Page 54 and 55: IV. Nonlinear Distortion Suppressio
Page 56 and 57: -10Optical Power (dBm)-20-30-40-50-
Page 58 and 59: Normalized Main Mode Power (dB)0-10
Page 60 and 61: frequency.Then, reduction of IMD3 i
Page 62 and 63: -10-20Detected RF power (dBm)-30-40
Page 64 and 65: -20RF Power (dBm)-30-40-50-60-70-80
Page 66 and 67: V. SummaryIn analog fiber-optic lin
Page 68 and 69: VI. References[1] W, I, Way, “Bro
Page 70 and 71: quantum-well lasers,” J. Quantum
Page 72: .__________________________________

Nonlinear Distortion Analysis of Directly Modulated ... - 연세대학교

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