EYDFA and EDFA are both optical fiber amplifier, but they are quite different in structure, performance, and application scenarios. Below let’s expose them one by one.
Differences in structure and working principle
| Characteristic | EYDFA | EDFA |
| Doped element | Er ³ ⁺+Yb ³ ⁺ co doped fiber | Single erbium ion (Er ³ ⁺) doping |
| pumping method | Double clad structure, supporting multi-mode pump lasers | Single mode fiber core pump, relying on high cost single-mode pump source |
| Energy transfer | Ytterbium ions absorb pump light energy and efficiently transfer it to erbium ions | Erbium ions directly absorb pump energy |
Performance parameter comparison
1. Output power and efficiency
EYDFA: Supports watt level output (27~35dBm), can replace 4~8 EDFAs with a single unit, and improves pump conversion efficiency by more than 10%;
EDFA: Typical output<27dBm (single-mode), significant degradation of noise index during cascaded amplification.
2. Gain and noise characteristics
EYDFA: The gain bandwidth covers 1530~1565nm (C-band), with better gain flatness and a noise figure comparable to EDFA (about 5.5dB);
EDFA: The gain bandwidth is similar, but the cumulative noise increases and CNR deteriorates when cascaded over long distances.
3. Nonlinear effect suppression
EYDFA requires optimized heat dissipation design due to high power output, but the double clad structure can reduce the risk of nonlinear scattering.
Application scenario differentiation
| scene | Advantages of EYDFA | Applicability of EDFA |
| Fiber to the Home (FTTH) in Cable TV | Single input multiple output (such as 8 × 23dBm), saving backbone fiber resources | Cascading is required, occupying more fiber ports |
| Ultra long distance transmission | Extension of relay free transmission distance by 50% to 100% | Multiple levels of relay are required, resulting in increased cost and complexity |
| Dense Wavelength Division Multiplexing (DWDM) | High power supports more channels, reducing unit channel costs | Output power bottleneck limits channel capacity |
Cost and operational impact
- Construction cost: EYDFA has a higher unit price, but at the system level, it can reduce the number of amplifiers and fiber occupation, resulting in a comprehensive cost reduction of over 30%;
- Operational complexity: EYDFA reduces node failure rate, making fault localization in EDFA cascade systems more difficult.
Technical selection suggestions
- High density user areas (such as FTTH): EYDFA is preferred to achieve single point high-power coverage;
- Short distance low-power scenario: EDFA is more flexible due to its modular packaging.
- Balance power demand, fiber optic resources, and long-term operation and maintenance costs.
