Bismuth doped fibers
BPDF (O-band)

BPDF-SM-5/125-1320 / BPDF-SM-8/125-1320

Bismuth doped fibers BPDF-SM-5/125-1320 / BPDF-SM-8/125-1320

Two bismuth-phosphorus fiber variants engineered for wideband gain across the O-band — 1280–1450 nm.

The BPDF-SM series is a bismuth-phosphorus co-doped fiber for amplifiers, lasers and superfluorescent sources across 1280–1450 nm — the O-band and its extension. Two variants are available: BPDF-SM-5/125-1320, optimized for low bending loss, and BPDF-SM-8/125-1320, built around two distinct bismuth active center (BAC) types for genuinely wideband amplification.

Customization — Two core/cladding geometries available (5/125 and 8/125). Other parameters are available on the request.

Datasheet FAQ

Key Advantages

Opens an underserved spectral window — one of few commercial high-gain fibers available for 1125–1200 nm.
MCVD-based, >99% silica glass — splices directly to standard fibers (< 0.35 dB with SMF-28, ~0.2 dB with Hi1060).
Practical gain and efficiency — >15% differential laser efficiency, 25 dB gain achievable in roughly 150 m of fiber.
Pump-flexible — efficiently pumped at 1050–1090 nm, compatible with Yb-fiber lasers or single-mode laser diodes, simplifying system design and cost.
Broad, tunable emission — amplification/SFS range of 1125–1200 nm, supporting sources with up to ~50 nm bandwidth.
Low-bend-loss variant available — for compact laser and amplifier packaging.

Why it matters: rare-earth-doped fibers (Yb, Er, Tm) leave a real gap around 1125–1200 nm — a window that matters for deep-tissue OCT, fluorescence imaging, and gyroscope/sensor light sources. Bismuth-aluminum active centers (BAC-Al) fill that gap directly in silica glass, without needing an entirely different fiber platform or exotic host glass.

Applications

SFS sources for 1130–1200 nm (up to ~50 nm bandwidth) for high-resolution OCT

CW and Q-switched lasers at 1178 nm for pumping Raman amplifiers

Fiber-optic gyroscope and sensor light sources

Biomedical lasers for photothermal coagulation, photodynamic therapy and in-vivo fluorescence

Fiber sensors in the 1.15–1.2 µm range

Metrology

FORC PUBLICATIONS OF BISMUTH DOPED FIBERS

O+E Band BDFA with Flattop 116 nm Gain Bandwidth Pumped with 250 mW at 1256 nm

Conference: OFC 2021. Autor: Aleksandr Khegai1, Yan Ososkov, Sergei Firstov,Konstantin Riumkin, Sergey Alyshev, Alexander Kharakhordin, Alexey Lobanov, Alexey Guryanov, and Mikhail Melkumov

Heterodyne photothermal spectroscopy of methane near 1651 nm inside hollow-core fiber using a bismuth-doped fiber amplifier

Journal: Vol.60, No.15, 20 May, 2021 Optical Society of America, Autor: Grzegorz Gomolka, Monika Krajewska, Aleksandr M. Khegai, Sergey V. Alyshev, Aleksey S. Lobanov, Sergei V. Firstov, Dariusz Pysz, Grzegorz Stepniewski, Ryszard Buczynski, Mariusz Klimczak, and Michal Nikodem

Operation of a Single-Frequency Bismuth-Doped Fiber Power Amplifier near 1.65 µm

Publication: Dec 9, 2020 in Photonics, Author: Grzegorz Gomółka, Monika Krajewska, Małgorzata Kaleta, Aleksandr M. Khegai, Sergey V. Alyshev, Aleksey S. Lobanov, Sergei V. Firstov and Michał Nikodem

O-band bismuth-doped fiber amplifier with 67 nm bandwidth

Conference: OFC 2020, Author:Aleksandr Khegai, Yan Ososkov, Sergei Firstov,Konstantin Riumkin, etc

Characterization of a single-frequency bismuth-doped fiber power amplifier with a continuous wave and modulated seed source at 1687nm

Publication: Vol. 59, No. 6 | 20 February 2020 | Applied Optics, Author: Grzegorz Gomolka, Aleksandr M. Khegai, Sergei V. Alyshev, Aleksey S. Lobanov, etc.

Lasing properties of thermally treated GeO2–SiO2 glass fibers doped with bismuth

Publication: Applied Physics B (2020) 126:87. Author: A. V. KharakhordIn, S. V. Alyshev, E. G. Firstova, A. S. Lobanov, etc.

25Gbs–1 data transmission using a bismuth-doped fibre amplifier with a gain peak shifted to 1300nm

Publication:Quantum Electronics 48(11) 989-992(2018). Author: M. A. Melkumov, V. Mikhailov, A. M. Khegai, K. E. Rjumkin, etc.

Wideband bismuth- and erbium-codoped optical fiber amplifier for C + L + U-telecommunication band

Publication: Laser Phys. Lett. 14(2017) 110001 (5pp). Author: S. V. Firstov, K. E. Riumkin, A. M. Khegai, S. V. Alyshev, M. A Melkumov, etc.

Bismuth/erbium-doped germanosilicate fibre amplifier with a bandwidth above 200nm

Publication:Quantum Electronics 46(11) 973-975 (2016). Author: E. M. Dianov, K. E. Riumkin, V. F. Khopin, S. V. Alyshev, etc.

Bi doped optical fibers and fiber lasers

Publication: IEEE JSTQE 2014. Autor: I.A. Bufetov, M.A. Melkumov, S.V. Firstov, K.E. Riumkin, A.V. Shubin, V.F. Khopin, A.N. Guryanov, and E.M. Dianov, Member, IEEE

Efficient Bi-doped fiber lasers and amplifiers for the spectral region 1300-1500 nm

Conference:2010 SPIE. Author: I. A. Bufetov, M. A. Melkumov, V. F. Khopin, S. V. Firstov, etc.

Need a bismuth-doped fiber matched to your gain band and package?

Contact our engineering team!

Bismuth doped fibers	BPDF-SM-5/125-1320	BPDF-SM-8/125-1320
Wavelength range, nm	1280 ÷ 1450	1280 ÷ 1450
Core diameter, µm	4.8 ± 0.4	7.8 ± 1.2
Clad diameter, µm	125 ± 5	125 ± 5
Coating diameter, µm	250 ± 20	250 ± 20
Polymer type	silicon rubber	silicon rubber or acrylate
Core NA	0.18 ± 0.02	0.13 ± 0.02
Cutoff wavelength, µm	1.15 ± 0.05	1.07 ± 0.05
Core absorption (1240 nm), dB/m	> 0.4	> 0.4
Amplification range (-3dB), nm	1300 ÷ 1415	1295 ÷ 1340
Typ. peak gain, dB/m	> 0.18 (Pp < 350mW @ 1320 nm)	> 0.2 (Pp < 350mW @ 1240 nm)
Small signal loss (@1550 nm), dB/km	n/a	< 35
Typical laser eff-cy, %	> 15% (vs pump power at 1200 nm)	> 20% (vs pump power at 1240 nm)

Other parameters are available on the request

Bismuth doped fiber (Articles BPDF-SM-5/125-1320 / BPDF-SM-8/125-1320)