Frequently Asked Questions

It provides amplification and gain across 1650–1780 nm, with peak gain around 1700 nm — the U-band.

The 0.4 NA, 3 µm core concentrates pump light tightly, which is necessary to achieve efficient gain in this less-common, longer-wavelength window; the trade-off is a higher splice loss (~1.2 dB) with standard SMF-28 fiber.

A notable application is trace-gas spectroscopy — FORC-Photonics' own published research uses bismuth-doped fiber amplifiers for heterodyne photothermal spectroscopy of methane near 1651 nm.

The fiber is pumped near 1470 nm and achieves greater than 20% laser efficiency versus pump power.