We demonstrate a silicon $1\times 64$ optical phased array by using carrier-depletion-based phase shifters. The 5-mm-long phase shifter exhibits an electro-optic bandwidth of 700 MHz, a modulation efficiency of 2.3 V.cm, and an ultra-low power consumption of < 0.45 nW/ $\boldsymbol {\pi }$ . A steering range of ±18° is realized in the phased-array axis by tuning the phase of each antenna. Besides, the beam steering in the other (wavelength-controlled) axis by tuning the wavelength achieves a dispersion efficiency of 0.17° /nm. Although the carrier-depletion effect induces a nonuniform optical amplitude distribution among the antenna array, the OPA chip is still able to form high-quality far-field beam patterns with side lobe suppression ratios of $\boldsymbol {\sim }10$ dB. Our measurement and simulation results indicate that the carrier-depletion-based OPA is a promising candidate for future high-speed and power-efficient solid-state Lidars.

We demonstrate an optical switch array based on the topology of Butterfly by using dual-microring resonators which can be used in the ultra-compact network. The proposed switch is composed of 12 basic switch elements tuned by thermo-optic (TO) effect, which can build links freely without any blocking. Due to the advantages of microring resonators, the footprint switch array is smaller than 0.2 mm ² . The optical structure can complete 4- and 8-ports signal routing. It shows a large bandwidth over 50GHz, thereby performing well under condition of high-speed data transmission.

We demonstrate a $1\times 256$ optical phased array based on the tri-layer Si ₃ N ₄ -on-Si platform. By optimizing the thickness and vertical position of the Si ₃ N ₄ overlay, the grating antenna exhibits a ultra-low emission rate of 13.9 dB/cm at 1550 nm and a large bandwidth of 120 nm. Based on the optimized Si ₃ N ₄ assisted grating antenna, the OPA realizes an ultra-sharp beam divergence of $0.154^{\circ }\times 0.0435$ , a two-dimensional beam steering range of $45.6^{\circ }\times 16.1$ , and a side lobe suppression ratio better than 10.8 dB.

Photonic neural networks (PNNs), as emerging analog computing paradigms, have the potential to break both the power consumption wall and processing speed boundary of digital computing architectures. However, most reported PNNs were mainly focused on real-valued regions, where phases of optical fields were only utilized as indirect information to affect optical amplitudes. Moreover, the quantization of phase information at each node of multi-layer PNNs is disregarded. In this work, we propose and demonstrate a Clements-enhanced complex-valued mesh (CCM) with balanced detection units (BDUs), which can capture both the amplitude and phase information at one layer and pass them on to the next layer. Besides, by introducing $N/2$ additional phase shifters to the Clements architecture, the proposed CCM possesses a complete characterization ability for arbitrary N-order complex unitary matrices. In this way, both the input vectors and the weighted matrices can be mapped into complex-valued regions and further implemented on the proposed CCM, in which the corresponding computing density is increased by four times with the comparison of real-valued meshes. To validate the proposed CCM with BDUs, we also fabricated a silicon-based on-chip 4×4 mesh with a footprint of 7.86 mm $^{2}$ and experimentally verified its performances on a two-class classification task of King-Rook vs. King (KRK) in chess and a ten-class classification of handwritten digits from MNIST database, yielding tested accuracies of 94.06 $\%$ and 91.75 $\%$ , respectively. The proposed passive on-chip CCM together with BDUs might provide another solution for next-generation artificial intelligence hardware with enhanced performances.

With the exponential growth in demand for transmission based on optical communication technology, providing secure transmission is crucial for the orderly development of individuals and groups in contemporary society. In the context of free-space optical (FSO) communication, we propose and experimentally demonstrate a novel physical layer security transmission scheme based on phase encryption controlled by chaotic sequences. Utilizing the chaotic Chen's equation to generate pseudo-random sequences as keys, we control the modulation of PAM4 signals on phase modulator to achieve phase encryption and decryption of user data. We successfully achieved 10 Gbps NRZ signal transmission over a free-space distance of approximately 3 meters, with a tested bit error rate (BER) lower than the hard-decision forward error correction (HD-FEC) limit. Additionally, we analyzed the influences of various encryption depths, FSO conditions, and delay matching on the system's transmission performance. To the best of our knowledge, this is the first application of chaotic phase encryption in FSO communication scenarios, which will inspire future developments in secure optical communication.