# Suppression of Nonlinear Optical Effects in DWDM-PON by Frequency Modulation Non-Coherent Detection

^{*}

## Abstract

**:**

## 1. Introduction

## 2. System Configuration and Simulation Model

#### 2.1. System Configuration

#### 2.2. Simulation Model

#### 2.2.1. Optical Transmitter

#### 2.2.2. Fiber-Optic Channel

#### 2.2.3. Optical Receiver

#### 2.2.4. The Other Devices

## 3. Numerical Simulation Results

^{−4}. Figure 7a,b indicate that the proposed FM-NCD system allows 200 wavelength channels with 10 Gb/s provided by each channel to multiplex together, as opposed to the 100 wavelength channels achievable with the conventional IM-DD system. The maximum system capacity of the FM-NCD system is twice that of the IM-DD system. These results verify the proposed FM-NCD system outperforms the conventional IM-DD system in resisting fiber nonlinearity, which results from the evenly distributed optical power of the FM signals.

## 4. Conclusions

## Supplementary Materials

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

- Tommaso, M.; Fabio, G.; Vittorio, P. Passive optical access networks: State of the art and future evolution. Photonics
**2014**, 1, 323–346. [Google Scholar] - ITUT, G.987.1; 10-Gigabit-Capable Passive Optical Networks (XG-PON): General Requirements. International Telecommunication Union: Geneve, Switzerland, 2016.
- ITUT, G.987.2; 10-Gigabit-Capable Passive Optical Networks (XG-PON): Physical Media Dependent (PMD) Layer Specification. International Telecommunication Union: Geneve, Switzerland, 2016.
- Banerjee, A.; Park, Y.; Clarke, F.; Song, H.; Yang, S.; Kramer, G.; Kim, K.; Mukherjee, B. Wavelength-division-multiplexed passive optical network (WDM-PON) technologies for broadband access: A review. J. Opt. Netw.
**2005**, 4, 737–758. [Google Scholar] [CrossRef] - ITUT, G.989.1; 40-Gigabit-Capable Passive Optical Networks (NG-PON2): General Requirements. International Telecommunication Union: Geneve, Switzerland, 2013.
- Talli, G.; Chow, C.W.; Townsend, P.; Davey, R.; Ridder, T.D.; Qiu, X.Z.; Ossieur, P.; Krimmel, H.; Smith, D.; Lealman, I.; et al. Integrated metro and access network: PIEMAN. In Proceedings of the 12th European Conference on Networks and Optical Communications (NOC), Stockholm, Sweden, 18–21 June 2007; p. 493. [Google Scholar]
- Muciaccia, T.; Gargano, F.; Passaro, V.M.N. A TWDM-PON with Advanced Modulation Techniques and a Multi-Pump Raman Amplifier for Cost-Effective Migration to Future UDWDM-PONs. J. Light. Technol.
**2015**, 14, 2986–2996. [Google Scholar] [CrossRef] - Davey, R.P.; Healey, P.; Hope, I.; Watkinson, P.; Payne, D.B.; Marmur, O. DWDM reach extension of a GPON to 135 km. J. Light. Technol.
**2006**, 24, 29–31. [Google Scholar] [CrossRef] - Lee, S.M.; Mun, S.G.; Kim, M.H.; Lee, C.H. Demonstration of a long-reach DWDM-PON for consolidation of metro and access network. J. Light. Technol.
**2007**, 25, 271–276. [Google Scholar] [CrossRef] - Boyd, R.W. Nonlinear Optics, 3rd ed.; Academic Press: Boston, MA, USA, 2008. [Google Scholar]
- Agrawal, G.P. Fiber Optic Communications Systems, 4th ed.; John Wiley & Sons: New York, NY, USA, 2010. [Google Scholar]
- Bellotti, G.; Bigo, S. Cross-phase modulation suppressor for multispan dispersion-managed WDM transmissions. IEEE Photon. Technol. Lett.
**2000**, 12, 726–728. [Google Scholar] [CrossRef] - Marhic, M.E.; Yang, F.S.; Kazovsky, L.G. Cancellation of stimulated-Raman-scattering crosstalk in wavelength-division-multiplexed optical communication systems by series or parallel techniques. J. Opt. Soc. Am. B
**1998**, 15, 957–963. [Google Scholar] [CrossRef] - Ip, E.; Kahn, J.M. Compensation of dispersion and nonlinear impairments using digital backpropagation. J. Lightw. Technol.
**2008**, 26, 3416–3425. [Google Scholar] [CrossRef] - Kikuchi, K. Fundamentals of coherent optical fiber communications. J. Lightw. Technol.
**2016**, 34, 157–179. [Google Scholar] [CrossRef] - Li, X. Optoelectronic Devices: Design, Modeling, and Simulation; Cambridge University Press: Cambridge, UK, 2009; pp. 1–361. [Google Scholar]
- Xin, L.; Zhao, J.; Li, X. Suppression of mode partition noise in FP Laser by frequency modulation non-coherent detection. IEEE Photon. J.
**2022**, 14, 7201310. [Google Scholar] [CrossRef] - Zuo, C.; Li, X. Polarization-Discriminated RSOA–EAM for Colorless Transmitter in WDM–PON. Appl. Sci.
**2020**, 10, 9049. [Google Scholar] [CrossRef] - Agrawal, G.P. Nonlinear Fiber Optics, 3rd ed.; Academic Press: New York, NY, USA, 2001. [Google Scholar]
- Lee, H.; Agrawal, G.P. Suppression of stimulated Brillouin scattering in optical fibers using fiber Bragg grating. Opt. Express
**2003**, 11, 3467–3472. [Google Scholar] [CrossRef] [PubMed] - Willems, F.W.; Muys, W. Suppression of interferometric noise in externally modulated lightwave AM-CATV systems by phase modulation. Electron. Lett.
**1993**, 29, 2062–2063. [Google Scholar] [CrossRef] - Boggio, J.M.C.; Marconi, J.D.; Fragnito, H.L. Experimental and numerical investigation of the SBS-threshold increase in an optical fiber by applying strain distributions. J. Lightwave Technol.
**2005**, 23, 3808–3814. [Google Scholar] [CrossRef] [Green Version] - Sinkin, O.V.; Holzlohner, R.; Zweck, J.; Menyuk, C.R. Optimization of the split-step Fourier method in modeling optical fiber communication systems. J. Light. Technol.
**2003**, 1, 61–68. [Google Scholar] [CrossRef] [Green Version] - Hardin, R.H.; Tappert, F.D. Applications of the split step fourier method to the numerical solution of nonlinear and variable coefficient wave equations. SIAM Rev. Chronicle.
**1973**, 15, 423. [Google Scholar] - Carema, A.; Curri, V.; Gaudino, R.; Poggiolini, P.; Benedetto, S. A time-domain optical transmission system simulation package accounting for nonlinear and polarization-related effects in fiber. IEEE J. Select. Areas Commun.
**1997**, 15, 751–764. [Google Scholar] [CrossRef] - Domash, L.; Wu, M.; Nemchuk, N.; Ma, E. Tunable and switchable multiple-cavity thin film filters. J. Lightw. Technol.
**2004**, 22, 126–135. [Google Scholar] [CrossRef] - Saunders, A.; Patel, B.L.; Harvey, H.J.; Robinson, A. Impact of cross-phase modulation for WDM systems over positive and negative dispersion NZ-DSF and methods for its suppression. IEEE Electron. Lett.
**1996**, 32, 2206–2207. [Google Scholar] [CrossRef] - Rapp, L. Experimental investigation of signal distortion induced by cross-phase modulation combined with dispersion. IEEE Photon. Technol. Lett.
**1997**, 9, 1592–1594. [Google Scholar] [CrossRef] - Shtaif, M.; Eiselt, M.; Garrett, L.D. Cross-phase modulation distortion measurements in multispan WDM systems. IEEE Photon. Technol. Lett.
**1997**, 12, 1592–1594. [Google Scholar] [CrossRef] - Ho, K.P. Statistical properties of stimulated Raman crosstalk in WDM systems. J. Lightw. Technol.
**2000**, 18, 915–921. [Google Scholar] - Jiang, Z.; Fan, C. A comprehensive study on XPM- and SRS-induced noise in cascaded IM-DD optical fiber transmission systems. J. Lightw. Technol.
**2003**, 21, 953–960. [Google Scholar] [CrossRef] - Jones, D.J.; Zhang, L.M.; Carroll, J.E.; Marcenac, D.D. Dynamics of monolithic passively mode-locked semiconductor lasers. IEEE J. Quantum Electron.
**1995**, 31, 1051–1058. [Google Scholar] [CrossRef] - Zhao, J.; Shi, K.; Yu, Y.; Barry, L.P. Theoretical analysis of tunable three-section slotted Fabry-Perot lasers based on time-domain travelingwave model. IEEE J. Sel. Topics Quantum Electron.
**2013**, 19, 1–8. [Google Scholar] [CrossRef] - Park, J.; Li, X.; Huang, W.P. Performance simulation and design optimization of gain-clamped semiconductor optical amplifiers based on distributed Bragg reflectors. IEEE J. Quantum Electron.
**2003**, 39, 1415–1423. [Google Scholar] [CrossRef] - Connelly, M.J. Wideband semiconductor optical amplifier steady-state numerical model. IEEE J. Quantum Electron.
**2001**, 37, 439–447. [Google Scholar] [CrossRef] [Green Version] - Park, J.; Li, X.; Huang, W.P. Comparative study of mixed frequency-time-domain models of semiconductor laser optical amplifiers. IEE Proc.-Optoelectron.
**2005**, 152, 151–159. [Google Scholar] [CrossRef]

**Figure 1.**Schematic representation of (

**a**) a long-reach DWDM-PON, whose transmitters and receivers are shown in (

**b**,

**c**) for the proposed FM-NCD scheme and in (

**b′**,

**c′**) for the conventional IM-DD scheme for comparison.

**Figure 2.**Characteristics of the FM transmitter: (

**b**) the output optical power and (

**c**) frequency chirp of the directly modulated DFB laser with (

**a**) the signal current applied, (

**d**) the optical power, and (

**e**) the spectrum of the optical signal after passing through the SOA.

**Figure 3.**System performance comparison between the TEF and LEF: (

**a**) the spectrum of the FM signal after 90 km optical fiber transmission, and frequency responses of the TEF and LEF; (

**b**,

**b′**) the eye diagrams of the optical signal after slope filtering by the TEF and LEF, respectively, with the extracted effective SNR (Q) and bit error rate (BER) shown at the top of each figure.

**Figure 4.**System performance of the TEFs with different bandwidths. The eye diagrams of the optical signal after slope filtering by the corresponding TEF are shown in the insets.

**Figure 5.**XPM-induced interference (normalized RMS) dependence on (

**a**) optical power with a frequency separation of 40 GHz, and (

**b**) frequency separation with the launched optical power of an interfering signal of 10 mW. The probe signal power launched into the fiber is maintained at 1 mW.

**Figure 6.**SRS-induced interference (normalized RMS) dependence on (

**a**) optical power with a frequency separation of 1 THz, and (

**b**) frequency separation with the launched optical power of an interfering signal of 10 mW. The probe signal power launched into the fiber is maintained at 1 mW.

**Figure 7.**(

**a**) BERs and (

**b**) eye diagrams of the proposed FM-NCD system and the IM-DD system with different system capacities.

Parameter | Symbol | Value | Unit |
---|---|---|---|

Bragg grating period | $\Lambda $ | 242.2 | nm |

Active region width | $w$ | 2 | μm |

Total quantum well thickness | $d$ | 0.05 | μm |

Active region length | $L$ | 200 | μm |

Optical confinement factor | $\Gamma $ | 0.06 | |

Grating coupling coefficient | $\kappa $ | 75 | cm^{−1} |

Carrier lifetime | ${\tau}_{c}$ | 0.1 | ns |

Group index | ${n}_{g}$ | 3.6 | |

Material gain coefficient | $a$ | 2000 | cm^{−1} |

Transparent carrier density | ${N}_{0}$ | 6 × 10^{17} | cm^{−3} |

Peak gain wavelength | ${\lambda}_{0}$ | 1550 | nm |

Nonlinear gain suppression coefficient | $\epsilon $ | 3 × 10^{−17} | cm^{3} |

Optical modal loss | $\alpha $ | 15 | cm^{−1} |

Reflectivity of front facet | ${R}_{f}$ | 0.3 | |

Reflectivity of back facet | ${R}_{b}$ | 0.95 | |

Effective index without injection | ${n}_{eff}^{0}$ | 3.2 | |

Spontaneous coupling factor | $\gamma $ | 1 × 10^{−4} | |

Linewidth enhancement factor | ${\alpha}_{LEF}$ | 8 | |

IIR filter coefficient | $\eta $ | 0.002 |

Parameter | Symbol | Value | Unit |
---|---|---|---|

Active region width | $w$ | 2 | μm |

Total quantum well thickness | $d$ | 0.05 | μm |

Active region length | L | 150 | μm |

Optical confinement factor | $\Gamma $ | 0.06 | |

Carrier lifetime | ${\tau}_{c}$ | 0.5 * | ns |

Group index | ${n}_{g}$ | 3.6 | |

Material gain coefficient | $a$ | 2000 | cm^{−1} |

Transparent carrier density | ${N}_{0}$ | 6 × 10^{17} | cm^{−3} |

Gain profile width | $\Delta {\lambda}_{G}$ | 80 | nm |

Peak gain wavelength | ${\lambda}_{0}$ | 1550 | nm |

Nonlinear gain suppression coefficient | $\epsilon $ | 3 × 10^{−17} | cm^{3} |

Optical modal loss | $\alpha $ | 15 | cm^{−1} |

Reflectivity of front facet | ${R}_{f}$ | 0.001 | |

Reflectivity of back facet | ${R}_{b}$ | 0.001 | |

Effective index without injection | ${n}_{eff}^{0}$ | 3.2 | |

Spontaneous coupling factor | $\gamma $ | 0.01 | |

Linewidth enhancement factor | ${\alpha}_{LEF}$ | 3 | |

Injected current | $I$ | 100 | mA |

Parameter | Symbol | Value | Unit |
---|---|---|---|

Dispersion parameter | D | 4, 17 * | ps/km/nm |

Dispersion slope | S | 0.075, 0.056 * | ps/km/nm^{2} |

Fiber loss | $\alpha $ | 0.2 | dB/km |

Nonlinear index coefficient | ${\overline{n}}_{2}$ | 2.6 × 10^{−20} | m^{2}/W |

Mode field diameter | d | 9.5 | μm |

Length | L | 90, 10 * | km |

Slope of the Raman gain profile | ${g}^{\prime}$ | 4.9 × 10^{−18} | m/W/GHz |

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**MDPI and ACS Style**

Xin, L.; Xu, X.; Du, L.; Sun, C.; Gao, F.; Zhao, J.
Suppression of Nonlinear Optical Effects in DWDM-PON by Frequency Modulation Non-Coherent Detection. *Photonics* **2023**, *10*, 323.
https://doi.org/10.3390/photonics10030323

**AMA Style**

Xin L, Xu X, Du L, Sun C, Gao F, Zhao J.
Suppression of Nonlinear Optical Effects in DWDM-PON by Frequency Modulation Non-Coherent Detection. *Photonics*. 2023; 10(3):323.
https://doi.org/10.3390/photonics10030323

**Chicago/Turabian Style**

Xin, Lei, Xiao Xu, Liuge Du, Chonglei Sun, Feng Gao, and Jia Zhao.
2023. "Suppression of Nonlinear Optical Effects in DWDM-PON by Frequency Modulation Non-Coherent Detection" *Photonics* 10, no. 3: 323.
https://doi.org/10.3390/photonics10030323