Sunjin Choi and Vladimir Stojanovic and Borivoje Nikolic

EECS Department, University of California, Berkeley

Technical Report No. UCB/

December 1, 2026

This report is delayed

The demands of today's AI workloads are fundamentally reshaping compute infrastructure, making interconnect bandwidth a first-order scaling constraint. While conventional electrical links continue to improve, increasing channel loss and equalization complexity make it difficult to scale both reach and bandwidth density. Microring Resonator-based Dense Wavelength Division Multiplexing (MRR-DWDM) offers a short-reach optical alternative that scales aggregate bandwidth through wavelength multiplexing over a shared optical path. To establish the system-level motivation for this architecture, I analyze how higher bandwidth and larger scale-up domains can enable more efficient batching and parallelism, thereby improving attainable distributed-inference throughput under latency constraints. I complement this workload-level analysis with a qualitative comparison of bandwidth-scaling mechanisms, positioning MRR-DWDM as a promising architecture for high-bandwidth short-reach interconnects. With this system context, the remainder of this dissertation addresses three challenges in advancing MRR-DWDM toward a robust and scalable short-reach optical transceiver architecture. First, I develop a physics-aware statistical link framework that translates resonator dynamics, inter-symbol interference, inter-channel crosstalk, and equalization onto a common power-penalty metric, revealing the link performance landscape across transmit and receive microring quality factors. Second, I formulate DWDM wavelength initialization as a policy-driven arbitration problem and develop wavelength-oblivious algorithms that establish robust cyclic wavelength ordering under device variation. Third, I present two fabricated high-speed receiver prototypes, a monolithically integrated optical DWDM receiver and an ADC-based electrical receiver, as comparative case studies showing how tighter integration shifts the locus of design complexity toward cross-domain physical implementation. Collectively, these studies show that scalable MRR-DWDM links require co-design across link physics, wavelength control, and silicon implementation.

Advisors: Borivoje Nikolic and Vladimir Stojanovic

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BibTeX citation:

@phdthesis{Choi:32303,
    Author= {Choi, Sunjin and Stojanovic, Vladimir and Nikolic, Borivoje},
    Title= {Toward Scalable Short-Reach DWDM Optical Links},
    School= {EECS Department, University of California, Berkeley},
    Year= {2026},
    Month= {Aug},
    Number= {UCB/},
    Abstract= {The demands of today's AI workloads are fundamentally reshaping compute infrastructure, making interconnect bandwidth a first-order scaling constraint. While conventional electrical links continue to improve, increasing channel loss and equalization complexity make it difficult to scale both reach and bandwidth density. Microring Resonator-based Dense Wavelength Division Multiplexing (MRR-DWDM) offers a short-reach optical alternative that scales aggregate bandwidth through wavelength multiplexing over a shared optical path. 
To establish the system-level motivation for this architecture, I analyze how higher bandwidth and larger scale-up domains can enable more efficient batching and parallelism, thereby improving attainable distributed-inference throughput under latency constraints. I complement this workload-level analysis with a qualitative comparison of bandwidth-scaling mechanisms, positioning MRR-DWDM as a promising architecture for high-bandwidth short-reach interconnects. 
With this system context, the remainder of this dissertation addresses three challenges in advancing MRR-DWDM toward a robust and scalable short-reach optical transceiver architecture. First, I develop a physics-aware statistical link framework that translates resonator dynamics, inter-symbol interference, inter-channel crosstalk, and equalization onto a common power-penalty metric, revealing the link performance landscape across transmit and receive microring quality factors. Second, I formulate DWDM wavelength initialization as a policy-driven arbitration problem and develop wavelength-oblivious algorithms that establish robust cyclic wavelength ordering under device variation. Third, I present two fabricated high-speed receiver prototypes, a monolithically integrated optical DWDM receiver and an ADC-based electrical receiver, as comparative case studies showing how tighter integration shifts the locus of design complexity toward cross-domain physical implementation. Collectively, these studies show that scalable MRR-DWDM links require co-design across link physics, wavelength control, and silicon implementation.},
}

EndNote citation:

%0 Thesis
%A Choi, Sunjin 
%A Stojanovic, Vladimir 
%A Nikolic, Borivoje 
%T Toward Scalable Short-Reach DWDM Optical Links
%I EECS Department, University of California, Berkeley
%D 2026
%8 December 1
%@ UCB/
%F Choi:32303