Satellite laser communication is a communication technology that uses laser light as an information carrier and free space as a transmission channel to establish high-speed data links between satellites, or between satellites and the ground. Compared to traditional microwave communication, laser communication boasts significant advantages—such as large bandwidth, high transmission rates, strong anti-interference capabilities, and high security—making it a core technology for building future spatial information networks. Currently, global low-Earth-orbit (LEO) constellations have entered a phase of large-scale construction, and inter-satellite laser communication has become a clear developmental trend.
Relying on decades of technological accumulation, traditional aerospace “National Team” players possess a strategic first-mover advantage in the field of space laser communication. They mainly comprise the following three major forces.
1. China Aerospace Science and Technology Corporation (CASC)
(1) The 504th Research Institute of the Fifth Academy (CAST Institute 504)
Since its establishment in 1965, CAST Institute 504 has served as a core force in China’s development of spacecraft payloads. In satellite laser communication—a strategically contested field—China started relatively late. At the time, only a few units nationwide were engaged in related research, and Institute 504 was the sole engineering development unit among them.
In 2008, Institute 504 started from scratch to tackle foundational engineering research for inter-satellite laser link demonstration and verification. In 2015, its research reached a critical node when it undertook the task of developing CASC’s first onboard laser terminal product. This marked Institute 504’s transition from ground-based pre-research to in-orbit deployment.
After three years of hard work, in March 2018, China’s first high-speed, high-order coherent laser communication terminal—developed by Institute 504—successfully completed its first-phase in-orbit test mission. The laser communication rate reached the highest level in China at the time, achieving a breakthrough from scratch for onboard laser terminal products.
Today, Institute 504 has not only established China’s first inter-satellite laser link, but also realized the world’s first satellite laser networking, with various technical indicators reaching advanced international levels. In 2025, Institute 504 completed the in-orbit verification of three regularly operating laser links within two months, setting a new record for the longest communication distance of laser links in China.
Overall, Institute 504’s core competitive edge is reflected in three aspects:
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Complete Payload System: It possesses the most complete communication payload development system within the state system, covering everything from antennas and radar to electronics.
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Extensive Verification Experience: Rich in-orbit verification experience accumulated across projects from Beidou Phase II to Micius and Shijian-20, yielding massive amounts of in-orbit data.
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System Integration: Backed by the Fifth Academy’s system integration capabilities, it can realize full-chain development from terminals to complete systems.
(2) The 704th Research Institute of the Ninth Academy (CASC Institute 704)
Since its founding in 1957, Institute 704 has consistently been a core force in China’s aerospace tracking, telemetry, and command (TT&C) communication field. In the early 21st century, with the global rise of space laser communication technology, Institute 704 gradually initiated pre-research layouts for space laser communication. It conducted extensive research into cutting-edge areas such as space laser communication network topology algorithms, integrated laser ranging and communication technology, and integrated deep-space microwave and laser communication technology.
In 2020, Institute 704 hit a key node in its commercial transformation. In April of that year, Xingyun Company issued a public tender for the “Xingyun Project” inter-satellite laser communication payload development project—marking the first public batch tender for onboard laser communication payloads in the domestic industry. In July, Institute 704 won the bid. Xingyun Company signed a procurement agreement for 12 sets of inter-satellite laser communication payloads with Institute 704 and Harbin Institute of Technology (Weihai).
Currently, Institute 704 has established a systematic intellectual property system in optical communications. In terms of patents, it holds core patents such as:
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“An Isolation Testing Device and Method for Transceiving Optical Modules in Laser Communication Systems”
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“A Coaxial Self-Calibration System for Transceiving in Space Laser Communication”
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“An Electro-Optic Nutation Coupling System and Method for Space Laser Communication”
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“An Optical Phased Array Laser Communication System Based on Multi-Aperture Coherent Synthesis”
In the H04B10/112 (Laser Communication System) patent classification, Institute 704 is one of the entities with the largest number of granted invention patents.
2. Chinese Academy of Sciences (CAS) System
(1) Shanghai Institute of Optics and Fine Mechanics (SIOM)
Founded in May 1964, SIOM is China’s earliest and largest professional research institute dedicated to laser science and technology. On August 16, 2016, a high-speed coherent satellite-to-ground laser communication experimental payload led by SIOM (in collaboration with the Innovation Academy for Microsatellites, Shanghai Institute of Technical Physics, and Institute of Optics and Electronics) was successfully launched aboard the Quantum Satellite (Micius). Adopting a coherent laser communication scheme, the payload achieved a maximum communication rate of 5.12 Gbps, featuring multi-rate switching and multi-service transmission capabilities for data, images, and video.
Building on the success of Micius, SIOM continued to deepen its work in space laser communication. In 2018, SIOM achieved an in-orbit test integrating 40,000-kilometer inter-satellite high-speed communication and measurement. This breakthrough pushed the laser communication distance from the 1,000-kilometer range to the 40,000-kilometer range, verifying the feasibility of establishing laser links between geostationary orbit (GEO) and medium/low Earth orbit (MEO/LEO) satellites. This provided key technical support for application scenarios like high-orbit data relay and deep-space communication.
In 2020, SG Communication Technology (Shanghai) Co., Ltd. was established, inheriting over two decades of SIOM’s technological accumulation and engineering experience. Its core product, a satellite laser communication terminal, uses a coherent detection scheme to establish inter-satellite laser links between coplanar and non-coplanar satellites. Beyond satellite terminals, SG Communication has developed series products including M21/M22 laser communication terminals, Acquisition, Tracking, and Pointing (ATP) telescopes, and SatNet laser terminal components, addressing multi-link communication needs from space to ground. Among them, telescope products using beaconless tracking technology can achieve sub-microradian optical axis pointing accuracy. Currently, SG Communication has become a core component supplier for the SatNet GW constellation and the Shanghai SpaceSail G60 constellation (providing laser communication terminals and related components for the latter).
(2) Xi’an Institute of Optics and Precision Mechanics (XIOPM)
Founded in 1962, XIOPM is the largest professional research institution for optics and precision mechanics in Northwest China. In 2004, XIOPM launched pre-research on space laser communication technology. Between 2016 and 2020, it tackled problems such as multi-format compatible communication and long-distance deep-space optical transmission.
XIOPM’s most core technological breakthroughs in spaceborne laser communication lie in two main directions: weak signal reception and high-speed coherent communication.
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Weak Signal Reception: This is the foundation of long-distance inter-satellite laser communication—distances between satellites often span thousands or tens of thousands of kilometers, causing extreme laser signal power attenuation. Achieving effective reception under extremely weak signal conditions directly determines the feasibility of the communication link.
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High-Speed Coherent Communication: After years of dedicated research, XIOPM has formed a complete technical system. Compared with non-coherent communication, coherent communication offers higher receiving sensitivity, stronger resistance to background light interference, and richer information extraction capabilities, making it an essential path to ultra-high-speed inter-satellite laser communication.
On July 16, 2026, XIOPM and its commercial aerospace industrialization platform, Xi’an CAS Star Bridge Technology Co., Ltd., announced that Shaanxi’s first specialized spaceborne laser communication intelligent production line—jointly built by the two—officially went into operation. Phase I of the line can produce 600 sets of laser communication terminals annually, with plans to achieve a capacity of over 1,000 sets per year by 2027, covering communication rates from 5 Gbps to 100 Gbps.
(3) Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP)
Founded in 1952, CIOMP is the cradle of China’s optical industry. In September 1961, CIOMP successfully developed China’s first ruby laser, ushering in the era of Chinese laser technology. Since then, CIOMP has continually advanced in fields such as laser physics, laser technology, and photoelectric detection, laying an irreplaceable disciplinary foundation for its entry into space laser communication.
Entering the 21st century, as global space laser communication technology emerged, CIOMP drew on its innate strengths in optics and lasers to make an early strategic entry into space laser communication. In 2021, large-scale laser communication calibration equipment developed by CIOMP for the Beidou Global System successfully completed high-speed satellite-to-ground downlink laser communication tests.
As an industrial platform incubated by CIOMP, Chang Guang Satellite Technology Co., Ltd. used the Jilin-1 Platform 02A01 and 02A02 satellites in early 2024 to conduct China’s first inter-satellite laser 100 Gbps ultra-high-speed, high-resolution remote sensing image transmission test. During the stable link period, the bit error rate (BER) was zero, and high-resolution remote sensing images transmitted between satellites were successfully downlinked to the ground. In December 2024, Chang Guang Satellite used its self-developed vehicle-mounted laser communication ground station and the onboard laser terminal on the Jilin-1 Platform 02A02 satellite to perform China’s first satellite-to-ground laser 100 Gbps ultra-high-speed, high-resolution remote sensing image transmission test, successfully acquiring Jilin-1 satellite remote sensing images.
3. China Aerospace Science and Industry Corporation (CASIC) System
In the field of satellite laser communication, the primary force within the CASIC system is the Beijing Institute of Remote Sensing Equipment (CASIC 2nd Academy Institute 25). Driven by the inter-satellite high-speed communication requirements of the “Hongyun Project,” Institute 25 began tackling key technologies in 2018.
On June 7, 2023, at 12:10 PM, two sets of LEO inter-satellite laser communication terminals developed by Institute 25 were carried aboard two separate satellites and launched successfully via CAS Space’s Lijian-1 Y2 rocket. Subsequently, inter-satellite and satellite-to-ground information transmission tests were conducted. Institute 25 successively completed satellite-to-ground calibration, satellite-to-ground link tests, and inter-satellite link tests for the two laser communication payloads. These tests verified technologies such as composite bidirectional acquisition and scanning for satellite platforms and laser payloads, optoelectronic closed-loop tracking, dynamic calibration of optical transceiving axes, and high-speed, stable inter-satellite/satellite-to-ground communication.
Compared to other entities, Institute 25 carries a unique “gene” from precision guidance technology. The high-precision target acquisition, tracking, and pointing technologies accumulated by Institute 25 in precision guidance align highly with the core technical requirements of inter-satellite laser communication. This technical migration path—”from missiles to satellites”—is quite unique within China’s aerospace system.
