Summer School on Optics & Photonics Mitigating Transmitter Non-linearity and ... over Fiber... · Mitigating Transmitter Non-linearity and Fiber ... Conclusion and future scope

Mitigating Transmitter Non-linearity and Fiber

Impairments in Radio over Fiber Technology

Dhananjay Patel

PhD student,

ECED, SVNIT, Surat

Supervisor:

Dr Mrs. U. D. Dalal

Associate Professor

ECED, SVNIT, Surat

Summer School on Optics & Photonics

National Institute of Technology, Surat, India

Outline

• RoF introduction

• Dispersion in optical fibers

• RoF OFDM transmission and reception using the

conventional and modified SSB

• Analysis of HD2 due to MZM, chromatic and modal

dispersion in SMF-MMF

• Conclusion and Future scope

• Publications

• References

5.6.2017 Summer school on optics and

photonics, Oulu, Finland

2

Introduction

• The increasing consumer demands to access the internet

requiring larger broadband network capacity should extend up

to the feed fixed terminals at the customer premises

• Single mode fibers (SMF) are typically used in Wide Area

Networks (WAN), Metropolitan Area Networks (MAN) and also

find applications in Radio over Fiber (RoF) architectures

supporting data transmission in Fiber to the Home (FTTH),

Remote Antenna Units (RAUs)

• Multi-mode fibers (MMFs) with low cost, ease of installation and

low maintenance are predominantly (85% to 90%) deployed in

in-building networks providing data access in local area

networks (LANs).5.6.2017 Summer school on optics and


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4



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Radio over Fiber technology

5.6.2017 Summer school on optics and photonics, Oulu, Finland 7

Signal Distortion on Optical Fibers -

Dispersion



8

Types of dispersion

Intra modal or

Chromatic

dispersion

Inter modal

dispersion

Dispersion

Material

Dispersion

Waveguide

Dispersion



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Optical modulator - MZM

5.6.2017 10

System Setup

System Parameter Value

RF frequency 18 GHz

Laser power, Linewidth,

Wavelength

-2dBm, 10MHz,

1552nm

Switching voltage of MZM 4V

Bias voltage of MZM, Phase

shift

2V and 1.33V for

90 and 120

degrees

Fiber length, dispersion &

attenuation

Up to 25Kms,

16.75 ps/nm/km

and 0.2 db/km

PIN responsitivity 0.8 A/W5.6.2017 11

Optical Spectrum of conventional

OSSB and proposed OSSB

90о Hybrid Coupler 120о Hybrid Coupler5.6.2017 12

Effect of DC bias voltage on 2nd order sideband

optical power for modified OSSB

3

dc

VV

Patel Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Assessment of Fiber Chromatic Dispersion

Based on Elimination of Second-Order Harmonics in Optical OFDM Single Sideband Modulation

Using Mach Zehnder Modulator." Fiber and Integrated Optics 35.4 (2016): 181-195.

dcV is the DC bias voltage andV is the MZM switching voltage

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Effect of ER on 2nd order sideband optical power

As ER increases from 5 to 25dB, the 2nd order optical SB power reduces

from -28.4 to -48.5dBm.

Patel, D., Singh, V. K., & Dalal, U. D. ,"Performance analysis of single sideband modulation technique using Mach

Zehnder Modulator based on different phase angles of electrical hybrid coupler, " Optik- International Journal

for Light and Electron Optics, vol.128,93–100, January 2017

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Optical OFDM generation,

transmission, and direct detection



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Mathematical modelingGeneration of the OFDM signal

Consideration of all the Laser and MZM parameters to generate the corresponding SSB OFDM signal

Taking Fourier Transform of the generated signal and expansion using the Bessel function

Transmission of the optical SSB signal through the SMF considering all the non-linear properties. Multiply the frequency transfer function of

dispersive and

nonlinear SMF with the optical SSB signal

Conversion of the received signal back to time domain by Inverse Fourier transform

Conversion of the optical signal back to electrical by multiplying the Responsitivity of the photodiode with the modulus squared of the optical

signal

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Optical spectrum of SSB signal using

90° hybrid coupler with ER = 6 dB

Optical spectrum of SSB signal using 90°

hybrid coupler with ER = 30 dB.


120° hybrid coupler with ER = 6 dB


120° hybrid coupler with ER = 30 dB.

5.6.2017 17

EVM analysis for 4 QAM OFDM transmission

Patel Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Assessment of Fiber Chromatic Dispersion Based on Elimination of Second-

Order Harmonics in Optical OFDM Single Sideband Modulation Using Mach Zehnder Modulator." Fiber and Integrated Optics 35.4

(2016): 181-195.

18


5.6.2017 19


5.6.2017 20

OFDM drive power and MZM non-

linearity

Linear

RegionNon - Linear

Region

Threshold point

= 9.98dBm5.6.2017 21

EVM vs received optical power

ECMA threshold= -

14.5dB

Improvement in

receiver sensitivity =

4.77%

5.6.2017 22

Generation of m-QAM OFDM signal

and transmission through SMF-MMF

fiber link



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Mathematical modelingThe output optical signal from the SMF is multiplied with the transfer function

of the MMF

Conversion of the optical signal back to electrical by multiplying the Responsitivity of the photodiode with the modulus squared of the optical

signal

Differentiating the current equation in to two parts based on normalized field distribution in same mode and in neighboring modes

Expanding the current equation up to second order where one part represents the HD2 due to MZM non linearity and other part represents HD2 due to modal

dispersion of the MMF

The Equation can be split into three parts considering the beating components formed due to beating of carrier and the first-order harmonic , carrier and the second-

order harmonic , first-order and the second-order harmonic for both the MZM and modal dispersion

The HD2 is calculated individually for MZM non linearity and modal noise by using Total Harmonic Distortion formula

5.6.2017 24

Influence of the modulation index on

HD2 on conventional SSB

Optical spectrum of the SSB technique with 90° hybrid coupler for different MZM

modulation index.

(a) MI = 0.1 (b) MI = 0.5 (c) MI = 1



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Optical spectrum of the SSB technique with 120° hybrid coupler for different MZM

modulation index.

Influence of the modulation index on

HD2 on modified SSB

(a) MI = 0.1 (b) MI = 0.5 (c) MI = 1

5.6.2017 26

Effect of HD2 due to MZM non-linearity and modal

dispersion over different MMF length

At length 500m, the SSB

with 120° hybrid coupler

provides a suppression of

the HD2 by 12 dB more

than the conventional one.

Patel Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Analysis of second order harmonic

distortion due to transmitter non-linearity and chromatic and modal dispersion of optical OFDM SSB

modulated signals in SMF-MMF fiber links." Optics Communications 383 (2017): 294-303

5.6.2017 27

Conclusion and future scope

• The optimum OFDM drive power is calculated for all the MZM

modulation techniques such that the MZM non-linearity is

minimum.

• The SSB technique using the 120° hybrid coupler improves the

receiver sensitivity as compared to the all other MZM

modulation techniques.

• Problems of chromatic dispersion, modal dispersion is reduced

by employing SSB technique using the 120° hybrid coupler in

SMF and MMF fibers.

• The SSB technique using the 120° hybrid coupler can be

employed in bidirectional systems to reduce the impact of

Rayleigh backscattering and discrete reflections5.6.2017 Summer school on optics and


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Publications

1. Patel, Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Performance evaluation of

optical OFDM in direct detected systems based on MZM bias and drive

voltages." Telecommunication Systems (2017): 1-11. Springer

2. Patel, Dhananjay, and U. D. Dalal. "A novel wavelength reused bidirectional RoF-

WDM-PON architecture to mitigate reflection and Rayleigh backscattered noise in

multi-Gb/s m-QAM OFDM SSB upstream and downstream transmission over a

single fiber." Optics Communications 390 (2017): 26-35. Elsevier

3. Patel, Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Analysis of second order

harmonic distortion due to transmitter non-linearity and chromatic and modal

dispersion of optical OFDM SSB modulated signals in SMF-MMF fiber links." Optics

Communications 383 (2017): 294-303. Elsevier

4. Patel, Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Performance analysis of

single sideband modulation technique using Mach Zehnder Modulator based on

different phase angles of electrical hybrid coupler." Optik-International Journal for

Light and Electron Optics 128 (2017): 93-100. Elsevier5.6.2017 Summer school on optics and


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5. Patel, Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Assessment of fiber

chromatic dispersion based on elimination of second-order harmonics in optical

OFDM single sideband modulation using Mach Zehnder Modulator." Fiber and

Integrated Optics 35.4 (2016): 181-195. Taylor & Francis

6. Patel, Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Chirped and Chirped Free

Optical OFDM MMW Generation with Direct Detection to Overcome Fiber

Chromatic Dispersion and MZM Non Linearity." Journal of Optoelectronics and

Advance Materials (JOAM), (in press).

7. Patel, Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Assessment of the DC Bias

to Mitigate the Clipping Noise in DCO-OFDM, ACO-OFDM; and Non-linear

Distortion of DFB Laser Transmitted through Dispersive Single Mode Fibers in

IM/DD Systems." Wireless Personal Communications,

(2017).doi:10.1007/s11277-017-4170-y. Springer

8. Patel, Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "On the effect of the

extinction ratio and the modulation index on optical up conversion using DSBSC

modulation and transmitting over different fiber links." Optik-International Journal

for Light and Electron Optics 127.24 (2016): 11845-11853. Elsevier5.6.2017 Summer school on optics and


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9. Dhananjay Patel & U. D. Dalal. "System Design and Analysis of a Novel

Wavelength Reused High Speed Bidirectional ROF-WDM-PON Architecture using a

M-QAM OFDM SSB Modulation Technique to Mitigate Chromatic Dispersion,

Reflection and Rayleigh Backscattering over a Single Mode Fiber." OSA and SPIE

sponsored International conference on “Development in optics and

communication- DOCRIGA 2017”, at Riga Latvia (2017).

10. Patel Dhananjay, Vinay Kumar Singh, and U. D. Dalal. "Performance Analysis of

Optical Double Sideband and Optical Single Sideband Generation using Mach

Zehnder Modulator Chirp and Extinction Ratio over Different Fiber Link." In 2nd

IEEE International Conferences For Convergence of Technology (I2ct), Pune,

India.

11. Patel Dhananjay, Vinay Kumar Singh, and U. D. Dalal. " Performance Evaluation of

a Single Mode-Multi Mode Cost Efficient Fiber Link used for 4/16/64 QAM Gigabit

OFDM MMW Transmission using Different MZM Modulation Schemes." In 2nd

IEEE International Conferences For Convergence of Technology (I2ct), Pune,

India.5.6.2017 Summer school on optics and


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References

[1] Chowdhury, A.; Hung-Chang Chien; Yu-Ting Hsueh; Gee-Kung Chang, "Advanced System Technologies and

Field Demonstration for In-Building Optical-Wireless Network With Integrated Broadband Services,"

in Lightwave Technology, Journal of , vol.27, no.12, pp.1920-1927, June15, 2009

[2] Gee-Kung Chang; Chowdhury, A.; Zhensheng Jia; Hung-Chang Chien; Ming-Fang Huang; Jianjun Yu; Ellinas,

G., "Key Technologies of WDM-PON for Future Converged Optical Broadband Access Networks [Invited],"

in Optical Communications and Networking, IEEE/OSA Journal of , vol.1, no.4, pp.C35-C50, September 2009

[3] Beas, J.; Castanon, G.; Aldaya, I.; Aragon-Zavala, A.; Campuzano, G., "Millimeter-Wave Frequency Radio over

Fiber Systems: A Survey," in Communications Surveys & Tutorials, IEEE , vol.15, no.4, pp.1593-1619, Fourth

Quarter 2013

[4] Ming-Fang Huang; Jianjun Yu; Zhensheng Jia; Gee Kung Chang, "Simultaneous Generation of Centralized

Lightwaves and Double/Single Sideband Optical Millimeter-Wave Requiring Only Low-Frequency Local

Oscillator Signals for Radio-Over-Fiber Systems," in Lightwave Technology, Journal of , vol.26, no.15,

pp.2653-2662, Aug.1, 2008

[5] Barros, D.J.F.; Kahn, J.M., "Comparison of Orthogonal Frequency-Division Multiplexing and On-Off Keying in

Amplified Direct-Detection Single-Mode Fiber Systems," in Lightwave Technology, Journal of , vol.28, no.12,

pp.1811-1820, June15, 2010

[6] Schmidt, B.; Lowery, A.J.; Armstrong, J., "Experimental Demonstrations of Electronic Dispersion Compensation

for Long-Haul Transmission Using Direct-Detection Optical OFDM," in Lightwave Technology, Journal of ,

vol.26, no.1, pp.196-203, Jan.1, 2008

[7] Min Xue; Shilong Pan; Yongjiu Zhao, "Optical Single-Sideband Modulation Based on a Dual-Drive MZM and a

120° Hybrid Coupler," in Journal of Lightwave Technology, vol.32, no.19, pp.3317-3323, Oct.1, 1 2014

[8] M. Xue, Y. J. Zhao, X. W. Gu, and S. L. Pan, “Performance analysis of optical vector analyzer based on optical

single-sideband modulation,” J. Opt. Soc. Amer. B, vol. 30, pp. 928–933, 2013.5.6.2017 Summer school on optics and


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Summer School on Optics & Photonics Mitigating Transmitter Non-linearity and ... over Fiber... · Mitigating Transmitter Non-linearity and Fiber ... Conclusion and future scope