Vertical cavity surface emitting laser (VCSEL) based short reach optical solutions are widely deployed in the applications with the aggregated data rate from 10 Gb/s to 400 Gb/s and transmission distance less than 100m. Even with the great advantages of power consumption and cost, 100 Gb/s per lane multimode interconnect is still at stake due to the great challenges imposed by VCSEL design and multimode transmission. Besides the bandwidth challenge, co-design of VCSEL and electrical driver in both circuit and packaging level become significantly important with electrical and photonic chips getting close in a co-package form factor. In this paper, we will establish the theory on the VCSEL modeling and propose a comprehensive electro-optical co-design framework for power-efficient high-speed VCSEL transmitter targeting at 50 Gbaud. Bandwidth enhancement based on photon-photon resonance is also investigated with VCSELs injection locked by an optical frequency comb.
A digital signal processing (DSP) scheme based on Volterra equalizer (VE) combined with adaptive noise-whitening post-filter and maximum likelihood sequence detection (MLSD) is proposed to mitigate nonlinear impairments in vertical-cavity surface-emitting lasers (VCSEL) multimode fiber (MMF) system. Successfully transmission of 108 Gb/s, 100 Gb/s and 60 Gb/s 4-ary pulse amplitude modulation (PAM4) signal over 5 m, 160 m and 460 m OM3-MMF is demonstrated below the 7% overhead hard-decision forward error correction (HD-FEC) bit error rate (BER) threshold by using a 20-GHz class VCSEL at 850 nm. Linear pre-equalization is applied to mitigate severe bandwidth limitation of the system. Our experimental results show that the scheme can well mitigate modulation nonlinearity induced by VCSEL and fiber nonlinearity induced by MMF. The BER decreases about two order of magnitude compared to linear equalizer after 100 m OM3-MMF transmission for 100 Gb/s PAM4 signal.
Vertical cavity surface emitting laser (VCSEL) and multimode fiber (MMF) based short reach optical solutions are widely deployed as the optical engines in the intra-datacenter communications since its significant advantages of low cost, easy design and test, high yield and low power consumption. With the increasing demand for highspeed interconnects, more than 100-Gb/s per lane and more than 100m transmission distance are highly required in order to meet future 4×100 Gb/s and 800G/1T module deployment in the high performance computing systems including datacenters and supercomputers. In this paper, we propose the comprehensive optical and electrical equalization approaches for the bandwidth limited devices, with the typical VCSEL 3-dB bandwidth around 20 GHz, to deal with the challenges including the inherent modal and chromatic dispersion, modulation nonlinearity and various noises in order that multimode interconnect could reach 100 Gb/s/lane over the distance more than 100m. To mitigate the various noises due to the multimode nature of the interconnect solutions, we propose the spatial phase manipulation scheme to dynamically control the coupling coefficients between the VCSEL and MMF links. We further investigate the physical limitations of the VCSEL during multilevel modulation, and propose the level dependent equalization approaches for the PAM4 modulation. Finally, more advanced nonlinear equalization, Volterra equalization, is investigated and a simplified version named by threshold based pruned retraining Volterra equalization (TRVE) is experimentally demonstrated for the VCSEL enabled 100 Gb/s PAM-4 over 100m MMF. Up to 94.2% and 88.0% complexity reduction has been achieved for B2B and 100m.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.