How can optical signals achieve efficient transmission and precise control within tiny chips in optical communication devices, overcoming distance and loss limitations?
Publish Time: 2025-11-28
In an era of explosive data growth, optical communication has become a core technology supporting global information infrastructure. As the "brain" and "nerves" of optical communication systems, optical communication devices are rapidly developing towards high integration, miniaturization, and high speed. However, within chips at the micrometer or even nanometer scale, optical signals are easily lost due to scattering, absorption, mode mismatch, and other factors, making long-distance stable transmission and high-precision control difficult.1. Low-Loss Waveguides: Building On-Chip "Optical Highways"The transmission of optical communication devices within chips relies on optical waveguides, whose performance directly determines the magnitude of signal loss. Current mainstream silicon-based photonics platforms utilize high refractive index contrast to highly localize the light field within the sub-micrometer scale, forming a transmission channel with low mode field diffusion. By optimizing the waveguide cross-sectional shape, sidewall roughness, and bending radius, researchers have reduced transmission loss to below 0.1–1 dB per centimeter.2. High-Performance Active Devices: Achieving Precise "Command" of Optical SignalsLow-loss transmission alone is insufficient for optical communication devices; optical signals must be precisely modulated, amplified, or detected. Thin-film lithium niobate modulators, with their ultra-high bandwidth, low drive voltage, and linear response characteristics, have become ideal choices for high-speed optical control. Regarding light sources, due to the extremely low luminous efficiency of silicon itself, the industry employs heterogeneous integration technology to bond III-V group laser chips such as indium phosphide to silicon optical platforms, achieving efficient and stable on-chip laser output. Photodetectors, through monolithic integration of germanium and silicon, achieve high-speed, high-sensitivity photo-to-electric conversion, completing signal closed-loop.3. Advanced Coupling and Packaging Technologies: Bridging the Last Millimeter Between Chip and FiberIf the low-loss internal components of the chip cannot efficiently interface with external optical fibers, the overall system performance will still be limited. Therefore, edge couplers and surface grating couplers are widely used. Among them, reverse-designed grating couplers can achieve broadband, high alignment tolerance coupling efficiency, with insertion loss controlled within 1 dB. Furthermore, co-packaging optics and optoelectronics co-packaging technologies deeply integrate optical engines and computing chips at the packaging level, significantly shortening electrical interconnect distances, reducing power consumption and latency, and fundamentally alleviating the "bandwidth wall" and "power wall" problems.4. New Materials and Intelligent Design: Opening New Paths to Future BreakthroughsFaced with the approaching physical limits, the scientific community is exploring new paths. Two-dimensional materials such as graphene possess ultrafast carrier response speeds and can be used in ultra-compact modulators; topological photonic crystals can achieve backscatter-immune light transmission, significantly improving anti-interference capabilities. Simultaneously, AI-based reverse design methods can automatically optimize complex photonic structures, achieving optimal multi-objective performance within limited space, breaking through the limitations of traditional manual design.Optical communication devices achieve efficient and precise optical signal manipulation within tiny chips, representing a collaborative innovation integrating materials science, micro/nano fabrication, electromagnetic theory, and systems engineering. From low-loss waveguides to high-performance active devices, from advanced coupling technologies to intelligent algorithm empowerment, each breakthrough continuously expands the "flying boundaries" of light on chips. It is the continuous evolution of these technologies that has enabled optical communication to carry the infinite possibilities of the terabit era within a small space.
