Short Reach Communication Technologies for Client-Side Optics Beyond 400 Gbps

Pang, Xiaodan; Udaļcovs, Aleksejs; Schatz, Richard; Bobrovs, Vjačeslavs; Jacobsen, Gunnar; Popov, Sergei; Ozoliņš, Oskars

doi:10.1109/lpt.2021.3078255

Cited by 11 publications

(1 citation statement)

References 22 publications

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“…Therefore, it is more likely to firstly extend the intensity-modulation and directdetection (IM/DD) technologies to DR (500 m) or DR+ (2 km) coverage at 200 Gb/s/lane with parallel single mode fiber (PSM) configurations. Further extending the IM/DD technologies to support FR (2 km CWDM4) and even LR applications (6 km/10 km LAN-WDM4) becomes exceptionally challenging considering the required power budget to compensate for the CD-induced power penalties and > REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < 2 therefore remains to be explored [3].…”

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confidence: 99%

200 Gb/s Optical-Amplifier-Free IM/DD Transmissions Using a Directly Modulated O-Band DFB+R Laser Targeting LR Applications

Pang

Salgals

Louchet³

et al. 2023

J. Lightwave Technol.

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We experimentally demonstrate an O-band singlelane 200 Gb/s intensity modulation direct detection (IM/DD) transmission system using a low-chirp, broadband, and highpower directly modulated laser (DML). The employed laser is an isolator-free packaged module with over 65-GHz modulation bandwidth enabled by a distributed feedback plus passive waveguide reflection (DFB+R) design. We transmit high baud rate signals over 20-km standard single-mode fiber (SSMF) without using any optical amplifiers and demodulate them with reasonably low-complexity digital equalizers. We generate and detect up to 170 Gbaud non-return-to-zero on-off-keying (NRZ-OOK), 112 Gbaud 4-level pulse amplitude modulation (PAM4), and 100 Gbaud PAM6 in the optical back-to-back configuration. After transmission over the 20-km optical-amplifier-free SSMF link, up to 150 Gbaud NRZ-OOK, 106 Gbaud PAM4, and 80 Gbaud PAM6 signals are successfully received and demodulated, achieving bit error rate (BER) performance below the 6.25%-overhead harddecision (HD) forward-error-correction code (FEC) limit. The demonstrated results show the possibility of meeting the strict requirements towards the development of 200Gb/s/lane IM/DD technologies, targeting 800Gb/s and 1.6Tb/s LR applications.

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confidence: 99%

200 Gb/s Optical-Amplifier-Free IM/DD Transmissions Using a Directly Modulated O-Band DFB+R Laser Targeting LR Applications

Pang

Salgals

Louchet³

et al. 2023

J. Lightwave Technol.

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Adaptive decision threshold algorithm based on a sliding window to reduce BER of free-space optical communication systems

Ying,

Zheng,

Wei

et al. 2024

Appl. Opt.

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Free-space optical communication (FSOC) systems face susceptibility to several factors, such as transmission distance, atmospheric turbulence, and alignment errors. These elements contribute to fluctuations in the signal strength reaching the receiver. The resultant signal fluctuations can result in misjudgments and an elevated bit error rate (BER). This paper proposes an adaptive decision threshold algorithm based on a sliding window (ADTSW). By estimating received signal parameters and delimiting the amplitude interval, the algorithm ensures that the decision threshold tracks signal fluctuations, thereby reducing signal misjudgment. The effectiveness of the algorithm is validated through simulations and experimentation. When the signal peak-to-peak value fluctuates, simulation results demonstrate that the proposed algorithm achieves a 1-order-of-magnitude reduction in BER compared to the traditional fixed decision threshold (FDT) method. Under the influence of weak atmospheric turbulence with different scintillation variance, both simulation and experimentation indicate a 1-order-of-magnitude reduction in BER compared to the FDT method. The ADTSW algorithm proves its capability in minimizing misjudgments, thereby effectively reducing BER and improving communication quality.

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Direct detection transmission of a PAM signal with power fading mitigation based on Alamouti coding and dual-drive MZM

et al. 2022

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Power-fading impairment induced by fiber dispersion and photodiode detection imposes a fundamental limitation on the intensity-modulation direct-detection (IM-DD) transmission systems. In this work, we propose a cost-effective pulse-amplitude modulation (PAM) signal transmission scheme with power-fading mitigation enabled by Alamouti coding and dual-drive Mach-Zehnder modulator (DDMZM). By interleaving the symbol blocks in the time domain for upper- and lower-arm of the DDMZM, flat end-to-end frequency response can be obtained without spectral nulls after combining the photocurrents at odd and even time slots. For single channel demonstration, we experimentally transmit up to 160Gb/s PAM-4, 140Gb/s PAM-6, and 108Gb/s PAM-8 signals over 80 km standard single-mode fiber (SSMF) with bit-error rates (BERs) below the 20% soft-decision forward error correction (SD-FEC) threshold of 2.0×10−2. For wavelength division multiplexing (WDM) transmission, 8λ×150Gb/s PAM-4 signals spacing at 100 GHz can also achieve 80 km reach. Moreover, we compare the optical signal-to-noise ratio (OSNR) sensitivity with single sideband (SSB) scheme and evaluate the tolerance of bias deviation in numerical simulation. The proposed Alamouti coding-based scheme provides a hardware-efficient and dispersion-tolerant candidate for high-speed inter-data center interconnect (DCI) applications.

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Short Reach Communication Technologies for Client-Side Optics Beyond 400 Gbps

Cited by 11 publications

References 22 publications

200 Gb/s Optical-Amplifier-Free IM/DD Transmissions Using a Directly Modulated O-Band DFB+R Laser Targeting LR Applications

200 Gb/s Optical-Amplifier-Free IM/DD Transmissions Using a Directly Modulated O-Band DFB+R Laser Targeting LR Applications

Adaptive decision threshold algorithm based on a sliding window to reduce BER of free-space optical communication systems

Direct detection transmission of a PAM signal with power fading mitigation based on Alamouti coding and dual-drive MZM

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