The core manufacturing process of optical splitters mainly includes five major steps: wafer processing, optical path etching and deposition, chip cutting and testing, fiber array assembly, and final packaging and aging testing.
Wafer Processing
This is the starting point of all processes. Typically, a thin film with specific optical properties (such as silicon dioxide) is grown on a clean glass substrate (such as quartz glass) using processes like chemical vapor deposition, forming the rudimentary structure of a "planar optical waveguide." This substrate serves as the "canvas" for subsequent optical circuit fabrication.
Optical Path Etching and Deposition
This is the core step in defining the splitting function of the optical splitter.
First, the designed optical splitting circuit pattern (e.g., 1x2, 1x4, etc.) is precisely transferred onto the photoresist layer of the wafer using photolithography processes such as coating, exposure, and development.
Then, the thin film material in the unprotected areas is etched away using dry or wet etching techniques, creating micron-sized optical waveguide channels on the wafer.
Finally, to protect these precise optical waveguide circuits, a cladding layer is deposited.
Chip Cutting and Testing
The entire wafer with the completed optical circuits is laser-cut into individual optical splitter chips. Before entering the next stage, each chip undergoes rigorous preliminary optical testing to verify whether key parameters such as splitting ratio and insertion loss meet the standards, thus screening out qualified products.
Fiber Array Assembly and Coupling
This process is responsible for "introducing" and "extracting" optical signals from the chip. One input fiber and several output fibers need to be precisely aligned and attached to both ends of the waveguide channels on the chip; this step is called fiber array assembly. This is followed by extremely precise optical coupling alignment to ensure the highest light transmission efficiency between the fibers and the waveguides on the chip. This is a crucial step in determining the quality of the finished product and is usually performed automatically by high-precision equipment.
Packaging and Aging Tests
The assembled chips are placed in metal or plastic packaging to protect them, and may be sealed with adhesive to ensure their long-term environmental reliability. Before shipment, the finished products must undergo comprehensive final testing, including high-temperature aging and full parameter testing. Only products that pass all parameters are packaged and shipped.
