Basic Knowledge of ELSFP in CPO Structure and its future
Basic Knowledge of ELSFP in CPO Structure
In the CPO architecture, the computing chip (ASIC) and the optical engine are co packaged, but the optical signal still needs to be connected to the outside through optical fibers. EL-SFP is the 'external optical interface'. It is no longer a traditional standalone optical module, but an extension socket for CPO onboard optical engines.
The core idea of ELSFP is to move the laser with high heat generation from the inside of the switch to the outside, and guide the light into the chip through optical fibers:
In traditional solutions, each optical module comes with its own laser, while high-density switch panels have a large number of lasers and generate a lot of heat. ELSFP integrates lasers into a pluggable module and uses fiber optic splitting to import multiple optical engines. One module can supply light to several silicon optical engines. Not only does it require high-precision coupling equipment, but due to its special position in the CPO architecture, the requirements for coupling processes are even higher than traditional pluggable optical modules.
In traditional schemes, each optical channel typically requires its own laser. The more channels there are, the more lasers there are, causing BOM costs and supply chain complexity to skyrocket simultaneously. But, ELSFP has changed its gameplay. Industry data shows that laser usage can be reduced by about 75%.
Question: How will the market change?
ELSFP has changed from "optional" to "essential", affecting not just one or two companies, but the value distribution of the entire optical communication industry chain.
1. The most direct beneficiaries are upstream optical devices.
The core materials of ELSFP are two: high-power CW lasers and polarization maintaining fiber components. Whoever has the packaging and testing capabilities for large-scale laser chips will be able to reap this incremental wave. At present, domestic manufacturers have launched high-power DFB laser series in the 100mW, 200mW, and 400mW levels.
2. Polarization maintaining fiber is another underestimated link.
The demand for polarization maintaining fibers in CPO and NPO architectures is structural. According to a research report by Fangzheng Securities, the amount of polarization maintaining fiber used in a single CPO/NPO device exceeds 100 meters, and the price of polarization maintaining fiber can exceed 100 yuan per meter. The growth logic of this market is completely different from before, as it has transformed from specialized optical fibers in professional fields to "standard consumables" for computing infrastructure.
3. The battle among CPO supporting manufacturers is also accelerating.
ELSFP is not a universal component. It needs to be deeply adapted to the optical engine of the CPO switch, with matching interfaces, power, and wavelength. This means that whoever completes joint verification with the switch manufacturer first gets the ticket to enter. Cambridge Technology has clearly stated that it has engaged in customized NPO development with multiple clients, including top cloud providers, and is expected to ship in small quantities in the first quarter of next year.
Summary of the trend:
ELSFP solves a physics problem - if a laser is sensitive to heat, then move it away from the heat source. This logic is simple to almost naive, but the implementation of engineering requires the cooperation of the entire industry chain.
The transfer of value upstream is an ongoing process - the incremental logic of high-power lasers, polarization maintaining fibers, and CPO supporting modules.
