Comparison of Coherent and IMDD Transceivers for Intra Datacenter Optical Interconnects

Cheng, Jinrong; Xie, Chongjin; Chen, Yizhao; Chen, Xi; Tang, Ming; Fu, Songnian

doi:10.1364/ofc.2019.w1f.2

Cited by 67 publications

(35 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, optical field impairments such as chromatic dispersion and polarization mode dispersion can be digitally compensated by accessing the field information [3][4][5] . However, coherent transceivers are relatively costly due to the hardware complexity and tight specifications for lasers 6 . To address hardware complexity, photonic integration has become a promising solution 7 , but the issue of precise frequency control between the local oscillator and transmitter laser is inevitable.…”

Section: Introductionmentioning

confidence: 99%

Carrier-assisted differential detection

Shieh

Sun

2020

Light Sci Appl

View full text Add to dashboard Cite

To overcome power fading induced by chromatic dispersion in optical fiber communications, optical field recovery is a promising solution for direct detection short-reach applications, such as fast-evolving data center interconnects (DCIs). To date, various direct detection schemes capable of optical field recovery have been proposed, including Kramers −Kronig (KK) and signal−signal beat interference (SSBI) iterative cancellation (IC) receivers. However, they are all restricted to the single sideband (SSB) modulation format, thus conspicuously losing half of the electrical spectral efficiency (SE) compared with double sideband (DSB) modulation. Additionally, SSB suffers from the noise folding issue, requiring a precise optical filter that complicates the receiver design. As such, it is highly desirable to investigate the field recovery of DSB signals via direct detection. In this paper, for the first time, we propose a novel receiver scheme called carrier-assisted differential detection (CADD) to realize optical field recovery of complex-valued DSB signals via direct detection. First, CADD doubles the electrical SE compared with the KK and SSBI IC receivers by adopting DSB modulation without sacrificing receiver sensitivities. Furthermore, by using direct detection without needing a precise receiver optical filter, CADD can employ cost-effective uncooled lasers as opposed to expensive temperature-controlled lasers in coherent systems. Our proposed receiver architecture opens a new class of direct detection schemes that are suitable for photonic integration analogous to homodyne receivers in coherent detection.

show abstract

Section: Introductionmentioning

confidence: 99%

Carrier-assisted differential detection

Shieh

Sun

2020

Light Sci Appl

View full text Add to dashboard Cite

show abstract

“…Digital Object Identifier: XXXXXXX communication systems [1]. Notably, intra-datacenter traffic with a typical link distance shorter than 2 km accounts for more than 80% of global traffic [2][3]. Such links require ultrahigh-speed interconnections (>100 Gb/s/) and significant experimental progress has already been achieved in this direction [4][5].…”

Section: Introductionmentioning

confidence: 99%

“…In [7][8][9], advanced modulation formats including 4-ary pulse amplitude modulation (PAM4) and discrete multi-tone (DMT), and their associated DSP algorithms have been demonstrated. PAM4 signaling, which offers a good compromise between scalability in data rate, complexity and cost of implementation, has been favored as the modulation format for intra-datacenter applications, and 4×100G PAM4 transceivers are expected to be commercialized in the near future [2]. A representative recent example of the remarkable progress that has been achieved in short-reach optical systems using PAM4 was reported in [7], where PAM4 signals were multiplexed on orthogonal polarizations and an additional inter-polarization phase modulation was combined with them to enhance the aggregate capacity.…”

Section: Introductionmentioning

confidence: 99%

Multi-Band Direct-Detection Transmission Over an Ultrawide Bandwidth Hollow-Core NANF

Hong

Sakr

Taengnoi

et al. 2020

J. Lightwave Technol.

View full text Add to dashboard Cite

In this paper, we report high-speed multi-band direct-detection (DD) transmission over a hollow-core nested antiresonant nodeless fiber (NANF). Thanks to the ultrawide bandwidth of the NANF, we demonstrate dual-band transmission across the O-and C-bands over a ~1-km length of a hollow-core fiber for the first time. Eight wavelength-division multiplexed (WDM) channels were transmitted using 100-Gb/s/ Nyquist 4-ary pulse-amplitude modulation (PAM4) signals, which to the best of our knowledge, is the highest aggregate capacity ever transmitted in a DD hollow-core fiber-based transmission system. Optical pre-amplification was adopted for signal reception in both bands, achieved using an in-house built bismuth-doped optical fibre amplifier (BDFA) and a commercial erbium-doped fiber amplifier (EDFA) in the O-and C-band, respectively. We further demonstrate beyond 100-Gb/s/λ adaptively-loaded discrete multitone (DMT) transmission over the S+C+L-bands using the same NANF, without the use of optical amplification. Our experiments show that apart from fiber loss, the use of the NANF did not introduce any additional transmission penalties. The demonstrated results validate the ultrawide bandwidth and excellent modal purity of the fabricated NANF, which allow beyond 100-Gb/s/ penalty-free transmission over multiple bands, highlighting the potential of this fiber technology for high-speed short-to intermediate-reach applications.

show abstract

“…Nonetheless, transmission in the O-band has high attenuation, which reduces the length of the transmission link [2]. Alternatively, solutions in the C-band, which address the intersymbol interference induced by dispersion, can also be considered [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…Coherent and direct detection (DD) systems are both possible technologies for C-band short-reach communication [3,6]. A coherent receiver has access to the amplitude and phase of the signal.…”

Section: Introductionmentioning

confidence: 99%

Tunable Optoelectronic Chromatic Dispersion Compensation Based on Machine Learning for Short-Reach Transmission

et al. 2019

View full text Add to dashboard Cite

In this paper, a machine learning-based tunable optical-digital signal processor is demonstrated for a short-reach optical communication system. The effect of fiber chromatic dispersion after square-law detection is mitigated using a hybrid structure, which shares the complexity between the optical and the digital domain. The optical part mitigates the chromatic dispersion by slicing the signal into small sub-bands and delaying them accordingly, before regrouping the signal again. The optimal delay is calculated in each scenario to minimize the bit error rate. The digital part is a nonlinear equalizer based on a neural network. The results are analyzed in terms of signal-to-noise penalty at the KP4 forward error correction threshold. The penalty is calculated with respect to a back-to-back transmission without equalization. Considering 32 GBd transmission and 0 dB penalty, the proposed hybrid solution shows chromatic dispersion mitigation up to 200 ps/nm (12 km of equivalent standard single-mode fiber length) for stage 1 of the hybrid module and roughly double for the second stage. A simplified version of the optical module is demonstrated with an approximated 1.5 dB penalty compared to the complete two-stage hybrid module. Chromatic dispersion tolerance for a fixed optical structure and a simpler configuration of the nonlinear equalizer is also investigated.

show abstract

Comparison of Coherent and IMDD Transceivers for Intra Datacenter Optical Interconnects

Cited by 67 publications

References 0 publications

Carrier-assisted differential detection

Carrier-assisted differential detection

Multi-Band Direct-Detection Transmission Over an Ultrawide Bandwidth Hollow-Core NANF

Tunable Optoelectronic Chromatic Dispersion Compensation Based on Machine Learning for Short-Reach Transmission

Contact Info

Product

Resources

About