TY - JOUR
T1 - Gerchberg-Saxton Based FIR Filter for Electronic Dispersion Compensation in IM/DD Transmission Part II: Experimental Demonstration and Analysis
AU - Wu, Xiong
AU - Karar, Abdullah S.
AU - Zhong, Kangping
AU - Gurkan, Zeynep Nilhan
AU - Lau, Alan Pak Tao
AU - Lu, Chao
N1 - This work was supported in part by the National Key R&D Program of China (No. 2018YFB1801701), in part by the National Natural Science Foundation of China (NSFC) (62101602, 62035018, U1701661), in part by the Project of the Shenzhen Municipal Science and Technology Innovation Commission (SGDX20201103095203030), in part by the Project of the Hong Kong Polytechnic University (G-SB1P), in part by the Hong Kong Government General Research Fund under project number PolyU 15220120 and PolyU 15217620, and in part by PolyU postdoc matching fund scheme of the Hong Kong Polytechnic University (1-W150).
Publisher Copyright:
IEEE
PY - 2022/11
Y1 - 2022/11
N2 - In this article, the first experimental demonstration of a non-iterative electronic dispersion compensation (EDC) solution implemented at the transmitter using a finite impulse response (FIR) filter optimized with the Gerchberg-Saxton (GS) algorithm, is presented, for intensity-modulation and direct-detection (IM/DD) systems. The theoretical framework for the GS FIR filter and preliminary simulations have been presented in Part I of this work. Here, the performance of the GS FIR filter is compared to that of the iterative GS algorithm in the transmissions of 56-Gb/s on-off keying (OOK) over 80 km of single mode fiber (SMF) with a post feed-forward equalizer (FFE) for combating residual inter-symbol interference (ISI). Furthermore, the influence of the pulse shape (raised cosine or rectangular) and modulation format (return-to-zero (RZ) or non-return-to-zero (NRZ)) on the measured bit error ratio (BER) is experimentally investigated, while changing the number of FIR taps, the number of post-FFE taps, and the number of post-FFE samples-per-symbol. It is shown that within the range of the target digital extinction ratios (DERs) for which the original iterative GS algorithm offers benefit, both analytical and numerical methods for calculating the optimum FIR taps, outlined in Part I of this work, produce similar BER performance as predicted. To that end, the former method is extended, here, through a non-recursive frequency response formula, which offers insight into the action of the GS filter with different pulse shaping and enables the derivation of the explicit GS impulse response. It is also shown that rectangular RZ pulse shaping exploits the full benefit of GS filtering through a uniform spectrum, enabling a BER below the 7% hard-decision forward error correction (HD-FEC) limit, with a 641-tap T/2-spaced pre-EDC FIR filter and a 3-tap adaptive T-spaced post-FFE.
AB - In this article, the first experimental demonstration of a non-iterative electronic dispersion compensation (EDC) solution implemented at the transmitter using a finite impulse response (FIR) filter optimized with the Gerchberg-Saxton (GS) algorithm, is presented, for intensity-modulation and direct-detection (IM/DD) systems. The theoretical framework for the GS FIR filter and preliminary simulations have been presented in Part I of this work. Here, the performance of the GS FIR filter is compared to that of the iterative GS algorithm in the transmissions of 56-Gb/s on-off keying (OOK) over 80 km of single mode fiber (SMF) with a post feed-forward equalizer (FFE) for combating residual inter-symbol interference (ISI). Furthermore, the influence of the pulse shape (raised cosine or rectangular) and modulation format (return-to-zero (RZ) or non-return-to-zero (NRZ)) on the measured bit error ratio (BER) is experimentally investigated, while changing the number of FIR taps, the number of post-FFE taps, and the number of post-FFE samples-per-symbol. It is shown that within the range of the target digital extinction ratios (DERs) for which the original iterative GS algorithm offers benefit, both analytical and numerical methods for calculating the optimum FIR taps, outlined in Part I of this work, produce similar BER performance as predicted. To that end, the former method is extended, here, through a non-recursive frequency response formula, which offers insight into the action of the GS filter with different pulse shaping and enables the derivation of the explicit GS impulse response. It is also shown that rectangular RZ pulse shaping exploits the full benefit of GS filtering through a uniform spectrum, enabling a BER below the 7% hard-decision forward error correction (HD-FEC) limit, with a 641-tap T/2-spaced pre-EDC FIR filter and a 3-tap adaptive T-spaced post-FFE.
KW - digital signal processing
KW - digital to analog converter
KW - electronic dispersion compensation
KW - finite impulse response filter
KW - Gerchberg-Saxton algorithm
KW - intensity modulation and direct detection
KW - Mach-Zehnder modulator
UR - http://www.scopus.com/inward/record.url?scp=85144045189&partnerID=8YFLogxK
U2 - 10.1109/JLT.2022.3223987
DO - 10.1109/JLT.2022.3223987
M3 - Journal article
AN - SCOPUS:85144045189
SN - 0733-8724
SP - 1
EP - 8
JO - Journal of Lightwave Technology
JF - Journal of Lightwave Technology
M1 - 9961872
ER -