BGDF (E-band)
BGDF‑SM series fibers include four variants. In the first three types (BGDF‑SM‑7/125‑1430, BGDF‑SM‑7/125‑1430‑HC, and BGDF‑SM‑7/125‑1430‑XC), the active absorption at 1400 nm increases sequentially by approximately 80–100%: 0.75 / 1.35 / 2.75 dB/m. The gain increases accordingly. All fibers are specifically designed for use in fiber amplifiers, lasers, and superluminescent fiber sources operating in the 1370–1490 nm wavelength range.
The BGDF‑SM‑7/125‑1430 fiber has the highest ratio of active absorption to unsaturable losses, enabling the lowest noise figure in amplifiers. It is recommended when achieving the minimum noise figure is the main priority in amplifier design or when maximum laser efficiency (>65%) is required.
BGDF‑SM‑7/125‑1430‑HC and BGDF‑SM‑7/125‑1430‑XC fibers allow the length of a laser or amplifier to be reduced by approximately 2 and 4 times, respectively, compared to the BGDF‑SM‑7/125‑1430 fiber. They are well suited for applications where minimizing device length is a priority.
The BGDF‑SM‑7/125‑1430PM fiber has a PANDA‑type structure and therefore supports polarization. The presence of a noticeable polarization‑dependent gain effect can be useful for achieving lasing in a single polarization.
...
Bismuth doped fibers | BGDF-SM-7/125-1430 | BGDF-SM-7/125-1430-HC | BGDF-SM-7/125-1430-XC | BGDF-SM-7/125-1430PM |
| Wavelength range, nm | 1370 ÷ 1490 | 1370 ÷ 1490 | 1370 ÷ 1490 | 1370 ÷ 1490 |
| Core diameter, µm | 6.5 ± 0.6 | 6.5 ± 0.6 | 6.5 ± 0.6 | 6.5 ± 0.6 |
| Clad diameter, µm | 125 ± 5 | 125 ± 5 | 125 ± 5 | 125 ± 5 |
| Coating diameter, µm | 230 ± 20 | 230 ± 20 | 230 ± 20 | 230 ± 20 |
| Coating material type | silicon rubber or acrylate | silicon rubber or acrylate | silicon rubber or acrylate | acrylate |
| Core NA | 0.14 ± 0.02 | 0.14 ± 0.02 | 0.14 ± 0.02 | 0.14 ± 0.02 |
| Cutoff wavelength, µm | 1.15 ± 0.1 | 1.15 ± 0.1 | 1.15 ± 0.1 | 1.15 ± 0.1 |
| Amplification range (-3dB), nm | 1410 ÷ 1450 | 1410 ÷ 1450 | 1410 ÷ 1450 | 1410 ÷ 1450 |
| Core absorption (1350 nm), dB/m | 0.3 ± 0.06 | 0.53 ± 0.1 | 1.1 ± 0.2 | 1.1 ± 0.25 |
| Typ. peak gain (@1430 nm), dB/m | > 0.3 (Pp ~ 200mW at 1310nm) | > 0.53 (Pp ~ 200mW at 1310nm) | > 1.1 (Pp ~ 200mW at 1310nm) | > 1.1 (Pp ~ 200mW at 1310nm) |
| Typ. gain (@1410 ÷ 1450 nm), dB/m | > 0.2 (Pp ~ 200mW at 1310nm) | > 0.33 (Pp ~ 200mW at 1310nm) | > 0.65 (Pp ~ 200mW at 1310nm) | > 0.65 (Pp ~ 200mW at 1310nm) |
| Approximate fiber length required to achieve amplification of a weak signal of 25 dB @ 1430 nm, m | 100 | 60 | 30 | 30 |
| Typical laser eff-cy (@1440nm), % | > 50% (vs pump power at 1310nm) | > 50% (vs pump power at 1310nm) | > 50% (vs pump power at 1310nm) | > 50% (vs pump power at 1310nm) |
| Splice loss with SMF28 (1310 nm), dB | ~ 0.2 | ~ 0.2 | ~ 0.2 | ~ 0.2 |
