Logic computing, a digital computational process grounded in Boolean logic, involves the processing of discrete signals through logic gates. It plays a pivotal role across numerous disciplines, including computer science, communications and electronics engineering, artificial intelligence, and emerging quantum computing, providing fundamental support for technological innovation and progress in modern information society. Chips serve as the hardware foundation for logic computing, executing fundamental computational tasks through logic circuits. These circuits, composed of tens of billions of transistors, enable chips to perform large-scale computations. The architectural design of a chip dictates its computational speed and efficiency, with distinct architectures tailored to specific computational tasks. Moreover, advancements in chip manufacturing technologies have fostered innovations in computational paradigms. Enhanced chip processes have led to devices with lower power consumption and greater performance, fueling the rapid expansion of big data, the Internet of Things, cloud services, and the rise of artificial intelligence. However, power consumption constraints have caused chip clock frequencies to plateau at a few gigahertz, and quantum uncertainty has rendered electronic transistors unreliable at nanoscale dimensions. Consequently, continued chip development is increasingly challenged in adhering to Moore’s Law. Additionally, the growing demand for computational power across emerging fields has exposed significant bottlenecks in traditional electronic computing, which reveals a substantial gap between current capabilities and actual requirements. Optical computing, with its advantages of high parallelism, low power consumption, low latency, and independence from advanced fabrication processes, offers a promising path to overcome Moore’s Law limitations. It holds the potential for the creation of high-performance, low-power chips. Extensive experience with digital circuits in very large-scale integration (VLSI) has demonstrated the critical role of logic computing due to its superior noise tolerance and high stability. By harnessing the low-power driving capabilities of optoelectronic devices, reconfigurable logic gates can execute a range of logic functions with ultra-low power consumption. The vast bandwidth of optical devices enables programmable logic arrays (PLAs) to dramatically enhance computational power. Additionally, the inherent speed of light propagation significantly reduces computational delays in arithmetic logic units (ALUs). Optical logic computing is emerging as a critical paradigm for the next generation of general-purpose photonic computing. While optical logic computing offers substantial performance benefits over traditional electronic chips, its large-scale implementation and application remain fraught with challenges. In recent years, discussions on its research progress and future development have been limited. Therefore, summarizing the existing research is essential to provide a sound foundation for the future trajectory of this field.

We provide an overview of the progress in optical logic computing and compare key metrics across different technological approaches. First, we define logic computing, discuss the conflict between computational power demands and chip development, and review recent advancements and landmark achievements in the field of optical logic computing. Then, we introduce the two primary paradigms of optical logic computing (Fig. 1): one based on linear and nonlinear optical effects for all-optical logic computing (Fig. 2), and the other based on thermo-optic, electro-optic, and phase-change effects for electro-optic logic computing (Fig. 5). These paradigms hold great promise for constructing high-speed, high-performance, and energy-efficient systems in the post-Moore era, where traditional electronic logic computing faces bottlenecks in computational power and energy consumption. They represent critical paradigms for the next generation of general-purpose photonic computing. The development of these paradigms has evolved from simple logic gates to programmable logic arrays, and further to general-purpose computing systems, such as state machines and cellular automata. Notably, progress has been made in overcoming bit-width limitations, with a shift toward three-dimensional integration. In addition, the emergence of more advanced logic paradigms in recent years, combined with the improvement of automated design methods, has propelled modularization. Hybrid digital-analog neural networks and two-dimensional cellular automata highlight the potential of optical logic computing to address large-scale computational tasks. We also explore the advantages, disadvantages, and potential breakthroughs of various technological routes (Tables 1 and 2), summarizing the significant challenges currently faced by both all-optical and electro-optical logic computing, including issues related to bit-width expansion, performance enhancement, energy consumption reduction, and programmability. Central challenges include excessive link loss, difficulties in cascading devices, and obstacles in restoring logic signals (Figs. 7 and 8).

The performance enhancement of contemporary general-purpose computing systems relying on electronic architectures has hit a bottleneck. Optical logic computing presents an opportunity to achieve breakthroughs in computational power, energy efficiency, and parallelism. The first step towards realizing this vision is to overcome the bandwidth, switching power, and device losses associated with electro-optic logic modulators while developing optical parallel logic and electro-optic multi-level loading to address bit-width limitations. This helps bridge the gap from fully electronic to fully optical general-purpose computing using electro-optic logic. The second step involves optimizing the loss and energy consumption of nonlinear optical devices, developing parallelizable all-optical nonlinear modules, and configuring programmable, general-purpose all-optical logic arrays. As diverse optical logic computing devices and architectures are demonstrated, optical logic computing becomes a fundamental building block for achieving arbitrary functionality in digital computing. This will bring revolutionary performance advancements in applications such as data centers, ultra-parameterized large models, and supercomputers.