In the rapidly developing field of space laser communications, the choice of wavelength is crucial for efficient and reliable data transmission, and the 1550nm wavelength has become the "golden band" due to its unique advantages, especially in combination with acousto-optic modulation technology. One of the main reasons for the popularity of 1550nm space AOM is its excellent atmospheric transmission characteristics. The Earth's atmosphere contains a variety of molecules and particles that can absorb, scatter and attenuate laser beams. Fortunately, the 1550nm wavelength is within the atmospheric window, and water vapor, oxygen and other atmospheric components have relatively low absorption of lasers. This allows laser signals of this wavelength to be transmitted over longer distances in the atmosphere with minimal energy loss. For air-to-ground or ground-to-air laser communication links, this means more stable and reliable signal reception, thereby reducing the impact of environmental factors on communication quality. The 1550nm wavelength is used in combination with an acousto-optic modulator (AOM) that can precisely control the characteristics of the laser beam, enabling precise modulation and demodulation of the signal, ensuring high-speed data transmission even in a turbulent atmosphere.

Another significant advantage of the 1550nm wavelength is its compatibility with fiber-optic communication systems. Optical fiber has become the backbone of terrestrial communication networks, and 1550nm is the optimal operating wavelength for standard single-mode optical fiber. Among the commonly used wavelengths of optical fiber, 1550nm has the lowest attenuation, which can achieve long-distance transmission while minimizing signal attenuation. In space laser communications, the use of lasers with a wavelength of 1550nm can simplify the interface and integration process when establishing a connection with the ground optical fiber network. AOMs operating at 1550nm can be seamlessly integrated into these systems, enabling efficient modulation of laser signals in space and ground communications. This compatibility not only reduces the complexity of communication infrastructure, but also improves the overall efficiency and scalability of air-to-ground communication networks. The maturity of 1550nm wavelength optical devices also makes it a golden band for space laser communications. For many years, people have been committed to the research and development of 1550nm wavelength optical components, including lasers, detectors, and modulators. As a result, high-performance, reliable, and cost-effective devices have become available. Acousto-optic modulators operating at a wavelength of 1550nm achieve high-speed modulation rates and excellent modulation depth, and can precisely control laser beam intensity, phase, and frequency. These advanced AOMs can support complex modulation formats, such as quadrature amplitude modulation (QAM) and phase shift keying (PSK), which are essential for improving the data transmission rate and spectral efficiency of space laser communication systems. The emergence of mature devices at 1550nm wavelength ensures the stability and reliability of space laser communication systems, and is also conducive to their mass production and widespread deployment.

In addition, from a safety perspective, the 1550nm wavelength is eye-safe at a certain power level. This feature is essential for ground operations and applications where there is a risk of personnel laser exposure. The use of 1550nm lasers in space laser communications makes it easier to meet safety requirements, reduce complex safety measures, and improve the practicality of communication systems. AOMs can further optimize laser output power and beam characteristics to ensure compliance with safety standards while maintaining high-performance communications.

In summary, the 1550nm wavelength has become the golden band for space laser communications due to its superior atmospheric transmission performance, compatibility with optical fiber systems, device maturity, and safety characteristics. Combined with advanced acousto-optic modulation technology, the 1550nm wavelength provides a powerful solution for high-speed, reliable and efficient space laser communications, laying the foundation for the development of future space communication networks.