Toward the information-theoretic limit of programmable photonics
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110803_1_5.0269741.pdf
Description
Published version
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6.17 MB
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Adobe PDF
Checksum (MD5)
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Author(s)
Hamerly, Ryan
Basani, Jasvith R
Sludds, Alexander
Vadlamani, Sri K
Englund, Dirk
Date Issued
November 4, 2025
Journal
APL Photonics
Publisher
AIP Publishing
Citation
Ryan Hamerly, Jasvith R. Basani, Alexander Sludds, Sri K. Vadlamani, Dirk Englund; Toward the information-theoretic limit of programmable photonics. APL Photonics 1 November 2025; 10 (11): 110803.
Version
Final published version
Abstract
The scalability of many programmable photonic circuits is limited by the 2π tuning range needed for the constituent phase shifters. To address this problem, we introduce the concept of a phase-efficient circuit architecture, where the average phase shift is ≪2π. We derive a universal information-theoretic limit to the phase-shift efficiency of universal multiport interferometers and, based on a modified Mach–Zehnder Interferometer (MZI) design, propose a “3-MZI” architecture that approaches this limit to within a factor of 2×, approximately a 10× reduction in average phase shift over the prior art, where the average phase shift scales inversely with system size N as O(1/N). For non-unitary circuits, we show that the 3-MZI saturates the theoretical bound for Gaussian-distributed target matrices. Using this architecture, we show optical neural network training with all phase shifters constrained to ≲0.2 radians without loss of accuracy.
MIT Department
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1063/5.0269741
