Optical Phased Array Research Articles

Analysis of the Influence of Fabrication Errors on the Far-Field Performance of Si and Si3N4 Antennas

Antennas are important components in optical phased arrays. However, their far-field performance deteriorates when random phase noise is introduced because of fabricating errors. For the first time, we use a finite-difference time-domain solution to quantitatively analyze the far-field characteristics of Si and Si3N4 antennas considering process errors. Under rough surface conditions based on a fishbone structure, we find that the quality of the main lobe of the Si antenna deteriorates badly, with −0.87 dB and −0.51 dB decreases in the sidelobe level and 5.78% and 3.74% deteriorations in the main peak power in the φ (phase-controlled) and θ (wavelength-controlled) directions, respectively. However, the Si3N4 antenna is only slightly impacted, with mere 0.39% and 0.71% deteriorations in the main peak power in the φ and θ directions, respectively, which is statistically about 1/15 of the Si antenna in the φ direction and 1/5 in the θ direction. The decreases in the sidelobe level are also slight, at about −0.08 dB and −0.01 dB, respectively. Furthermore, the advantages of the Si3N4 antenna become more remarkable with the introduction of random errors into the waveguide width and thickness. This work is of great significance for the design and optimization of OPA chips.

Optical phased array output beam calibration method based on Adam algorithm

<sec>Optical phased array (OPA) technology, as a pivotal component of laser detection and ranging (LiDAR) systems, plays a crucial role in augmenting the application efficiency in fields such as autonomous driving, precision measurement, and remote sensing detection. With the escalating demands for high-resolution imaging, the array size of OPAs is continuously expanding, imposing higher requirements on the calibration precision and efficiency of the output beam. Existing calibration algorithms, such as the simultaneous perturbation stochastic gradient descent (SPGD) and the Gerchberg-Saxton (GS) algorithm, often face challenges of prolonging calibration times and insufficient precision when dealing with large-scale OPA systems.</sec><sec>In order to address this problem, our study introduces the Adam optimization algorithm, renowned for its adaptive learning rate feature, into the calibration process of OPA output beams. Through simulation modeling and experimental validation, this work comprehensively examines the differences in performance between the Adam algorithm and conventional SPGD and GS algorithms in beam calibration, especially under various OPA array configurations. For a 16×16 OPA array, the application of the Adam algorithm significantly enhances the peak side lobe ratio (PSLR) to over 15.98 dB, while notably reducing the number of iterations to less than 600, thereby shortening the calibration cycle and improving calibration precision effectively.</sec><sec>Furthermore, this work provides an in-depth analysis of parameter selection, convergence speed, and stability of the Adam algorithm in OPA calibration, offering detailed guidance for achieving more efficient and high-quality beam calibration. Through comparative analysis, this work not only demonstrates the substantial advantages of the Adam algorithm in enhancing OPA calibration efficiency, reducing calibration duration, and optimizing output beam quality but also emphasizes its critical role in advancing OPA technology.</sec><sec>The main contribution of this work lies in providing an innovative algorithmic approach for achieving efficient calibration of OPA output beams, which has important theoretical and practical significance for advancing the LiDAR technology, particularly in the field of high-precision beam control. Moreover, by applying optimized algorithms, this study not only improves the performance of OPA technology within existing domains but also paves new ways for its application in emerging fields such as optical communication, optical networking, and high-resolution imaging.</sec>

Monolithically Integrated Optical Phased Array for Optical Wireless Communication

Monolithically Integrated Optical Phased Array for Optical Wireless Communication

Managing Grating Parameters for Longitudinal Steering with 1D Optical Phased Arrays

Managing Grating Parameters for Longitudinal Steering with 1D Optical Phased Arrays

Paper] Design for Stray Light Suppression of an Optical Phased Array with Electro-optic Polymer

Paper] Design for Stray Light Suppression of an Optical Phased Array with Electro-optic Polymer

Research on The Control Technology of Optical Phased Array High-Speed Scanning

Research on The Control Technology of Optical Phased Array High-Speed Scanning

Silicon-Based Waveguide Integrated Optical Phased Array Chips for LiDAR: Design Challenges and Breakthroughs (Invited)

Silicon-Based Waveguide Integrated Optical Phased Array Chips for LiDAR: Design Challenges and Breakthroughs (Invited)

Demonstration of inherently low differential phase noise across C-band in InP integrated, amplifying optical phased arrays

Demonstration of inherently low differential phase noise across C-band in InP integrated, amplifying optical phased arrays

Broadband, High Resolution, Sensitive Spectrometer Using an Integrated Optical Phased Array in Silicon Nitride and Fourier Imaging

Broadband, High Resolution, Sensitive Spectrometer Using an Integrated Optical Phased Array in Silicon Nitride and Fourier Imaging

Practical in-situ beamforming method for optical phased array LiDAR monitoring a single far-field point

Practical in-situ beamforming method for optical phased array LiDAR monitoring a single far-field point

Simplified Beam Steering and Fast Error Compensation of Optical Phased Arrays by Using a Novel Weighted-Grouping Algorithm

Simplified Beam Steering and Fast Error Compensation of Optical Phased Arrays by Using a Novel Weighted-Grouping Algorithm

Outlook on Development of Laser Communication from Perspective of Optical Phased Array Technology (Invited)

Outlook on Development of Laser Communication from Perspective of Optical Phased Array Technology (Invited)

Independent dual beams generated by array element division in integrated optical phased arrays

Independent dual beams generated by array element division in integrated optical phased arrays

Photonic integrated optical phased arrays and their applications [Invited

Photonic integrated optical phased arrays and their applications [Invited

Compact and Efficient Transverse Spliced Waveguide Grating Antenna for Integrated Optical Phased Array

Compact and Efficient Transverse Spliced Waveguide Grating Antenna for Integrated Optical Phased Array

Research Progress in Large Field of View Silicon-Based Optical Phased Array LiDAR Chip (Invited)

Research Progress in Large Field of View Silicon-Based Optical Phased Array LiDAR Chip (Invited)

Symmetrical Modular Optical Phased Array with Combined Spatial and Amplitude Modulation for Scalable Indoor Wireless Networks

Symmetrical Modular Optical Phased Array with Combined Spatial and Amplitude Modulation for Scalable Indoor Wireless Networks

Research Progress on Liquid Crystal Optical Phased Array Technology for Laser Communication (Invited)

Research Progress on Liquid Crystal Optical Phased Array Technology for Laser Communication (Invited)

Analysis of the Principle and State-of-art Applications of Si-Based Chip on Lidar

In recent years, as the feature size of transistors continues to decrease, Moore's Law is also approaching its limits. On this basis, In the post-Moore era, optical interconnect technologies with inherent attributes such as low latency, low power consumption, and low crosstalk have gained widespread attention in the industry. Silicon photonics technology has emerged, leveraging the accumulated knowledge from the silicon-based microelectronics industry over half a century. Optical phased arrays, unlike traditional mechanical-based lidar systems, offer advantages such as small size, low cost, and high accuracy. When combined with mature CMOS processes, they hold significant research value and market prospects. With this in mind, this study will discuss the principle as well as the state-of-art applications for Si-based chip on Lidar. According to the analysis, the current limitations are also demonstrated and suggestions are proposed based on the evaluations. Overall, these results shed light on guiding further exploration of chip developments on Lidar.

Design of optical phased array with low-sidelobe beam steering in thin film lithium niobate

Optical beam-steering devices are crucial components of complex optical control systems, which are widely used in diverse information-processing applications. Optical phased arrays (OPAs) as the promising beam-steering devices, have proven to alleviate current performance limitations in beam steering devices for ultra-small solid-state light detection and rangings (LiDARs) and free-space communication systems. The high electro-optic (EO) coefficient (γ33 = 30.9 pm/V) of lithium niobate (LiNbO3, LN) can be a useful platform for phase tuning of the OPAs, which is conducive to enable phase shifting for non-mechanical beam steering with high-speed and low power consumption. The design, configurations and LN-OPA corresponding performances are discussed in this paper. The OPA consisting of different waveguides array is optimized with a side lobe suppression lower than - 10 dB at the wavelength of 1.55 μm. Meanwhile, the OPA with grating emitters or adding silica cavity further improves the deflection quality of the beam. Then optical beam steering with an angle of 50° in one dimension controlled by the LN-OPA has been demonstrated. The proposed OPA on the LN platform in this work might hold significances for advanced LiDAR schemes based on EO tuning.