Photonic devices for Optical interconnect and computing

In the 21st century, with the continuous development of modern society, more and more data information are required to be processed and transmitted. Due to the physical nature, the photon is more suitable to transmit and process information with unique characteristics, including bosonic nature, wide bandwidth and high-data-rate density, low transmission loss, low power consumption, and simple system design. On the one hand, as a carrier of information, photons show great potential in interconnection even in very short distance; on the other hand, it is expected that photons (or light wave) can employed with non-von-Neumann architecture to complete identification tasks and solve optimization problems with high operation speed and energy efficiency. Optoelectronic devices based on silicon substrate are expected to integrate both photonic and electronic devices on the same chip. Thus, it is possible to achieve information transmission and processing as well as new functionalities with high-speed, large capacity, low power consumption on chip.

We are dedicated to implement optoelectronic devices with micro/nano-structure, including the light emitter, transmission line, passive devices, modulator and photonic integrated circuit on silicon platform. We are focused on the new materials, new structures, new mechanism and new breakthrough in science and technology, and try to explore highly integrated and low-powered optoelectronic devices with novel functionality and application, e.g. optical interconnect, optical processing, classical and quantum optical computing, et.al.

Research Topic

- Universal linear transformation and application on optical computing

- Integrated orbital angular momentum (OAM) devices

- Photonic integrated circuit and devices

              Integrated OAM emitter                              Beam splitter with metasurface                              Photonic “SUANPAN”

 

Representative Result

Universal linear optical operations

(1) Non-cascaded linear transformations: Taking inspirations from the conjugate pair of OAM state, i.e., angle state, the concept of the physically realizable quasi-angle state with high dimensionality is developed. Based on quasi-angle state, a method for high dimensional matrix transformation is proposed (Phys. Rev. A 95 (3): 33827, (2017), also Highlighted as the Editor’s Suggestion) and extended to discrete coherent spacial mode (DCS-mode).We have demonstrated the unitary transformation matrix with dimensionalities ranging from 7 to 24. (J. Opt. 21, 104003, (2019), special issue of “Twisted Waves and Fields”). Moreover, a simple and flexible scheme is demonstrated for the quantum Fourier transformation (QFT) and quantum state tomography (QST) with dimensionality of 15. The dimensionality of 15 is the highest dimensionality reported to the best of our knowledge. (Physical Review Applied, 14(2), 024027, (2020))

(2) Optical computing: Based on the high dimensional matrix transformation, we have proposed and demonstrated a programmable optical neural network (ONN) scheme for various image identification tasks (Optics Express, 29 (17): 26474-26485 (2021)). Furthermore, a fully reconfigurable and programmable photonic Ising machine is also demonstrated. Our proposal is named as the “Phase Encoding and Intensity Detection Ising Annealer” (PEIDIA). With PEIDIA, 30-spin Ising problems have been solved with high ground state probability (≥0.97/0.85 for the 20/30-spin Ising model). (Communications Physics, 7, 168, (2024)). Furthermore, PEIDIA architecture is also employed to implement an X-Y model solver (Physical Review Applied, 22, L021001 (2024)) as well as a16-channel on-chip photonic solver for quadratic unconstrained binary optimization (QUBO) problems (Chip, 4(1), 100117, (2025)).

(3) Integrated photonic reservoir computing based on hierarchical time-multiplexing structure: A micro-ring array (MRA) is employed as a typical time delay implementation of reservoir computing (RC). At the output port of the MRA, a secondary time-multiplexing is achieved by multi-mode interference (MMI) splitter and delay line array. Simulation results indicate that error rate of 0.5% and 2.7% are achieved for signal classification and chaotic time series prediction, respectively, while the sample rate is as high as 1.3Gbps (Optics Express 22(25): 31356-31370, (2014)).

 

Integrated orbital angular momentum (OAM) emitter

(1) Orbital angular momentum (OAM) of beams on chip is proposed for wireless optical interconnects and a full scheme of encoding and decoding of OAM is demonstrated with numerical simulation (Optics Express, 20(24), pp. 26986-26995, (2012)).Experimentally, Integrated “Cobweb” and “Cogwheel” emitters with a wide switching range of OAM Modes have been demonstrated (Scientific Reports 6: 22512, (2016), Scientific Reports 5, 10958, (2015)). Moreover, a heralded single-photon source with switchable OAM modes has been demonstrated on silicon chip. At room temperature, the heralded single photons with 11 OAM modes (l = 2–6, −6 to −1) are successfully generated and switched through thermo-optical effect. (Laser Photonics Rev., 16(12), 2270059, (2022)).  

(2) Plasmonic vortex: As a fundamental tool for light-matter interactions, plasmonic vortex (PV) is extremely attractive due to its unique near field properties. We have proposed a novel method of utilizing the propagation induced radial phase gradient of incident Laguerre-Gaussian (LG) beam to sculpture PVs from integer to fractional OAM dynamically. Furthermore, a series of plasmonic devices are proposed to generate multi-patterned and two-dimensional optical lattice with helicity or not. (Scientific Reports 6: 36269, (2016), Optics Letters 41 (7), 1478-1481, (2016)). Furthermore, based on phase modulated metallic nano-slits array, an angular momentum (AM) beam splitter has been demonstrated to distinguish both spin and orbital components carried by light beam. (ACS Photonics, 2020, 7(1): 212-220)

 

Photonic integrated circuit and devices

 (1) All silicon photonic integrated circuits based on silicon light source and slot waveguide operating at 1064 nm: Silicon slot waveguides operating at a wavelength of high silicon absorption are fabricated on SOI wafers. The measured transmission loss coefficient is as low as 6 ~ 8 dB/cm at 1064 nm which the bending loss of slot waveguides is measured as 4.1 ~ 4.6 dB/180^o with a bending radius of 15 μm. We believe that this work could pave the way to achieve all silicon photonic integrated circuits (PICs), which are very promising for future on-chip chemical/biological analysis. (IEEE Photonics Technology Letters 28(1): 19-22, (2016), Optics Communications 359: 129–134, (2016)，Optics Communications , 306, pp131–134, (2013), Optics Communications, 306: 131–134, (2013)). For the silicon light source, plasmonic enhancement of amorphous-silicon-nitride (-SiNx) light emission with single-layer gold (Au) waveguides was experimentally demonstrated through time-resolved photoluminescence measurement. The maximum Purcell factor value of ~3 is achieved with identified plasmonic resonance of the Au waveguide at ~530 nm. (This work was selected as “10 Breakthroughs of China Optics in 2013”)

(2) High performance integrated silicon devices: A silicon modulator with microring array assisted Mach-Zehnder interferometer (MZI) is experimentally demonstrated on silicon-on-insulator (SOI) wafer through CMOS-compatible process. The footprint of the whole modulator is about 600 μm². With forward-biased current-driven p-n junction, the voltage length product is measured as low as VπL < 6.63 × 10-3 V·cm while the 3-dB modulation bandwidth is ~ 2GHz. (Optics Express, 22 (9):10550-10558, (2014)). Tunable and reconfigurable microwave photonic filters have been proposed and experimentally demonstrated on silicon-on-insulator substrate. For bandpass filter, the operating frequency and -3-dB bandwidth can be tuned from 18 to 40 GHz and from 5 to 15 GHz, respectively (IEEE Photonics Technology Letters, 24(17):1502-1505, (2012)). To our knowledge, it is the first on-chip demonstration of tunable and reconfigurable microwave photonic filters.

(3) Novel metasurface devices: We have demonstrated a free-space optical multi-port beam splitter (MPBS) with arbitrarily predetermined port number, power ratio and spatial distribution of output beams. The experimental results reveal that high beam-splitting efficiency and fidelity within 100 nm bandwidth are achieved. (Advanced Optical Materials,11(20), 202300664, (2023))；We has proposed a novel miniaturized MOT beam delivery system based on meta-devices. The core of this system is a new type of polarization-decoupling multi-port beam-splitting (PD-MPBS) metasurface, which integrates multiple beam splitting and independent polarization control by combining propagation phase and geometric phase. (Advanced Science, e06289, (2025))；To increase the operating channels of polarization-multiplexed metasurfaces, we have proposed a structure of N cascaded dual-channel metasurfaces to achieve 2^N electrically switchable channels without intrinsic loss or cross-talk for certain functionalities, including beam steering, vortex beam generation, lens, etc.. As proof of principles, a 3-layer setup is implemented to achieve 8 channels. (Nature Communications, 15:8370, (2024))