Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical Interconnection
As for vertical-cavity surface-emitting lasers (VCSEL)-based optical pulse amplitude modulation (PAM) interconnection system, apart from the universal signal distortions like Gaussian noise and fiber dispersion, direct modulation of VCSEL specially induces level nonlinearity and level-dependent nois...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IEEE
2019-01-01
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| Series: | IEEE Photonics Journal |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/8756113/ |
| _version_ | 1818668301697417216 |
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| author | Lin Sun Jiangbing Du Ke Xu Bo Liu Zuyuan He |
| author_facet | Lin Sun Jiangbing Du Ke Xu Bo Liu Zuyuan He |
| author_sort | Lin Sun |
| collection | DOAJ |
| description | As for vertical-cavity surface-emitting lasers (VCSEL)-based optical pulse amplitude modulation (PAM) interconnection system, apart from the universal signal distortions like Gaussian noise and fiber dispersion, direct modulation of VCSEL specially induces level nonlinearity and level-dependent noise. To mitigate these two specific distortions in VCSEL-based link, a k-means assisted PAM-4 signal receiver including equalization and soft decision (SD) is proposed. Based on learned mean values and standard deviations for individual levels through k-means approach, probability density function of nonlinearly distorted PAM-4 symbols can thus be approximated more precisely than conventional SD, leading to improved decision performance. In addition, depending on k-means result, least means square (LMS) equalization with adapted levels can converge to a lower error value than conventional LMS, thanks to level nonlinearity mitigation. Consequently, by using proposed k-means equalization and SD, improved signaling performance can be obtained by mitigating the level nonlinearity and level-dependent noise. Both simulation and experiment are performed for evaluating the proposed method in a 100-Gb/s VCSEL-MMF PAM-4 optical interconnection system, by comparing with conventional means. |
| first_indexed | 2024-12-17T06:34:09Z |
| format | Article |
| id | doaj.art-d290fac4023c4878a791918536616101 |
| institution | Directory Open Access Journal |
| issn | 1943-0655 |
| language | English |
| last_indexed | 2024-12-17T06:34:09Z |
| publishDate | 2019-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Photonics Journal |
| spelling | doaj.art-d290fac4023c4878a7919185366161012022-12-21T22:00:04ZengIEEEIEEE Photonics Journal1943-06552019-01-0111411110.1109/JPHOT.2019.29269998756113Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical InterconnectionLin Sun0https://orcid.org/0000-0002-5725-180XJiangbing Du1https://orcid.org/0000-0002-6333-824XKe Xu2https://orcid.org/0000-0003-1935-8910Bo Liu3https://orcid.org/0000-0002-9603-9975Zuyuan He4https://orcid.org/0000-0002-7499-834XState Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai, ChinaState Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai, ChinaDepartment of Electronic and Information Engineering, Harbin Institute of Technology, Shenzhen, ChinaSchool of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing, ChinaState Key Laboratory of Advanced Optical Communication Systems and Networks, Shanghai Jiao Tong University, Shanghai, ChinaAs for vertical-cavity surface-emitting lasers (VCSEL)-based optical pulse amplitude modulation (PAM) interconnection system, apart from the universal signal distortions like Gaussian noise and fiber dispersion, direct modulation of VCSEL specially induces level nonlinearity and level-dependent noise. To mitigate these two specific distortions in VCSEL-based link, a k-means assisted PAM-4 signal receiver including equalization and soft decision (SD) is proposed. Based on learned mean values and standard deviations for individual levels through k-means approach, probability density function of nonlinearly distorted PAM-4 symbols can thus be approximated more precisely than conventional SD, leading to improved decision performance. In addition, depending on k-means result, least means square (LMS) equalization with adapted levels can converge to a lower error value than conventional LMS, thanks to level nonlinearity mitigation. Consequently, by using proposed k-means equalization and SD, improved signaling performance can be obtained by mitigating the level nonlinearity and level-dependent noise. Both simulation and experiment are performed for evaluating the proposed method in a 100-Gb/s VCSEL-MMF PAM-4 optical interconnection system, by comparing with conventional means.https://ieeexplore.ieee.org/document/8756113/Optical interconnectsfiber optics systems |
| spellingShingle | Lin Sun Jiangbing Du Ke Xu Bo Liu Zuyuan He Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical Interconnection IEEE Photonics Journal Optical interconnects fiber optics systems |
| title | Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical Interconnection |
| title_full | Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical Interconnection |
| title_fullStr | Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical Interconnection |
| title_full_unstemmed | Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical Interconnection |
| title_short | Enabling Equalization and Soft Decision by k-Means for VCSEL-Based PAM-4 Optical Interconnection |
| title_sort | enabling equalization and soft decision by k means for vcsel based pam 4 optical interconnection |
| topic | Optical interconnects fiber optics systems |
| url | https://ieeexplore.ieee.org/document/8756113/ |
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