As satellite networks continue to expand in scale and service demands grow rapidly, satellite networks face significant challenges due to limited spatial resources and insufficient transmission efficiency. Traditional switching mechanisms struggle to meet the demands of high-capacity, low-latency, and high-reliability inter-satellite communications. This challenge is especially pronounced as satellite constellations scale from hundreds to tens of thousands of satellites. Emerging applications such as ultra-high-definition video streaming, on-board artificial intelligence (AI) real-time inference, and edge computing on low Earth orbit satellites impose new and stringent performance requirements on on-board switching systems. These emerging applications demand on-board switching systems to support throughput at the Tbit/s level, end-to-end latency in the millisecond range, and energy efficiency on the order of μJ/bit, in order to meet the stringent power constraints of satellite platforms. However, traditional electrical switching systems are limited by interface bandwidth and power density, causing their switching capacity to stagnate at several hundred gigabits per second, making it difficult to support Tbit/s level traffic loads. Optical switching technology, with its ultra-wide bandwidth and low transmission loss, has increasingly become a focus of research and industry. However, on-board optical switching lacks flexible multi-granularity transmission capabilities, resulting in reduced switching efficiency when handling diverse types of traffics. In this context, we propose a high-capacity on-board optical/electric hybrid switching technology aimed at overcoming the physical limitations of traditional switching systems. This novel switching architecture integrates the flexible control of electrical switching with the high bandwidth advantages of optical switching, achieving both high throughput and low latency.

We propose a resource-constrained, high-capacity multi-directional optical/electric hybrid switching architecture that integrates multi-granularity electrical switching based on spatial frames with reconfigurable optical switching technology. The design aims to address the differentiated requirements of single-direction fine-grained multi-granularity traffic and multi-direction coarse-grained traffic switching within satellite payloads under limited spatial resource conditions. Specifically, the architecture consists of three main components: the master control module, the all-optical switching module, and the spatial frame switching module. The spatial frame switching module handles the switching of small-granularity and medium-granularity traffic within the satellite network by performing fine-grained switching inside the module. For large-granularity traffic switching across different directions within the satellite, data is modulated onto optical carriers and switched between directions via the all-optical switching module. The all-optical switching module adjusts its internal microlens array according to control information, directing input optical signals to the target spatial frame switching modules. This enables large-granularity data switch across multiple spatial directions between spatial frame switching modules. Additionally, this paper proposes a traffic rate adaptive matching technique based on the generic mapping procedure (GMP) and a low-insertion-loss, high-isolation, non-blocking all-optical switching technology. The former addresses the rate mismatch problem when multiplexing multiple signals into optical channel payload unit (OPU) frames and enables adaptive rate matching for signals from different clock domains. The latter overcomes the excessive insertion loss commonly encountered in traditional optical switching.

Experimental results demonstrate that the developed high-capacity on-board optical/electric hybrid switching platform successfully achieves full-granularity optical channel data unit (ODU) 0/ODU 2 switching and all-optical switching under a power consumption of no more than 90.72 W. By applying the service rate adaptive matching technique based on GMP, our payload successfully achieves adaptive rate matching from ODU 2 services to OPU 4. This resolves the clock domain mismatch issue commonly encountered in the asynchronous mapping of signals to higher-order OPU k frames in traditional electrical switching. Meanwhile, by employing the low-insertion-loss, high-isolation, non-blocking all-optical switching technology, the proposed system achieves all-optical switching with an insertion loss of no more than 2 dB (Table 1), significantly outperforming the loss levels of traditional all-optical switching modules. In addition, this paper presents an adaptability analysis of the potential effects of space environmental factors—such as radiation and temperature fluctuations—on the payload. By employing radiation-hardened field-programmable gate arrays (FPGAs), space-grade temperature-tolerant firmware, high-process materials, and real-time monitoring and adjustment through control software, the system’s reliability and stability under harsh space environmental conditions have been significantly enhanced.

To address the core challenges of high capacity, low latency, and energy efficiency in satellite networks, we introduce an innovative resource-constrained on-board optical/electric hybrid switching architecture, along with two key technologies: a service rate adaptive matching technique based on the GMP and a low-insertion-loss, high-isolation, non-blocking all-optical switching technology. Through the deep integration of spatial frame-based electrical switching and reconfigurable optical switching, this study achieves coordinated control of full-granularity ODU 0/ODU 2 electrical switching and all-optical switching under conditions of low power consumption and minimal resource usage. This work provides a highly reliable switching solution for mega satellite constellations. Its innovative hybrid control architecture and spatial frame scheduling mechanism significantly improve resource utilization in satellite networks. Moreover, it offers Tbit/s-level switching infrastructure for 6G space-air-ground integrated networks and lays a solid technical foundation for the development of optical/electric collaborative technologies in space-air-ground integrated communication systems.