Deep-learning-based high-resolution recognition of fractional-spatial-mode-encoded data for free-space optical communications

Author(s):

Na, Youngbin & Ko, Do-Kyeong

Abstract:

“Structured light with spatial degrees of freedom (DoF) is considered a potential solution to address the unprecedented demand for data traffic, but there is a limit to effectively improving the communication capacity by its integer quantization. We propose a data transmission system using fractional mode encoding and deep-learning decoding. Spatial modes of Bessel-Gaussian beams separated by fractional intervals are employed to represent 8-bit symbols. Data encoded by switching phase holograms is efficiently decoded by a deep-learning classifier that only requires the intensity profile of transmitted modes. Our results show that the trained model can simultaneously recognize two independent DoF without any mode sorter and precisely detect small differences between fractional modes. Moreover, the proposed scheme successfully achieves image transmission despite its densely packed mode space. This research will present a new approach to realizing higher data rates for advanced optical communication systems.”

Link to Publications Page

Publication: Scientific Reports
Issue/Year: Scientific Reports, Volume 11; Number 1; 2021
DOI: 10.1038/s41598-021-82239-8

High-Resolution Tunable Filter With Flexible Bandwidth and Power Attenuation Based on an LCoS Processor

Author(s):

Yunshu Gao, Genxiang Chen, Xiao Chen, Qian Zhang, Qiao Chen, Ce Zhang, Kai Tian, Zhongwei Tan and Chao Yu

Abstract:

“High-resolution optical filters and wavelength selective switches are the essential components in the current and next-generation dynamic optical networks. A high-resolution programmable filter for telecom application is proposed and experimentally demonstrated based on a 4 k phase-only liquid crystal on silicon (LCoS) spatial light modulator. The tuning resolution, bandwidth, and power attenuation for each wavelength channel can be modulated independently by remote software control. For each channel, the center wavelength is tuned in the step of 7.5 ± 1 pm and the 3 dB bandwidth achieves from 10 GHz to 3 THz. Furthermore, by multi-casting hologram design techniques for an LCoS, the power attenuation is adjusted from 0 dB to 30 dB with the step of 0.1 dB. The insertion loss is less than 6 dB across the entire C-band and 1.8 dB of it can be further improved by adopting an LCoS chip with smaller reflection loss. ”

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Publication: IEEE Photonics Journal
Issue/Year: Volume: 10 Issue: 6 (2018)
DOI: 10.1109/JPHOT.2018.2876347

Demonstration of a 3 texttimes 4 tunable bandwidth WSS with tunable attenuation using compact spatial light paths

Author(s):

Xie, Dequan; Liu, Zichen; You, Quan & Yu, Shaohua

Abstract:

“M × N wavelength selective switch (WSS) is a core component to address wavelength conflict in an optical switching node. In this paper, we design and experimentally demonstrate a performance enhanced 3 × 4 tunable bandwidth WSS (TBWSS) with tunable attenuation across the full C-band, and using compact spatial light paths. Wavelength channels from any input optical fiber port can be switched into any output optical fiber port with best insertion loss (IL) of 8.4 dB and worst IL of 12.5 dB. The attenuation tuning range can reach up to 35 dB. Compared to previous demonstrations, more than 2 dB IL improvement is achieved. Based on the proposed compact spatial light paths, the number of input and output ports can be easily extended to 10 and 20, respectively.”

Link to Publications Page

Publication: Optics Express
Issue/Year: Optics Express, Volume 25; Number 10; Pages 11173; 2017
DOI: 10.1364/oe.25.011173