Wide gain bandwidth C-band optical fiber amplifier
AssigneeOfsfitel, LLC
InventorBenyuan Zhu
Life of this patent
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Abstract
A fiber amplifier that is particularly configured to provide gain across a large extent of the C-band spectral range (i.e., a gain bandwidth of at least 42 nm, preferably within the range of 46-48 nm) utilizes a specially-designed discrete Raman amplifier in combination with a high inversion level EDFA to extend the gain bandwidth of a conventional EDFA C-band optical amplifier, while maintaining the gain ripple below an acceptable value. The EDFA provides operation at a highly-inverted level and the specialized discrete Raman amplifier (sDRA) element has particular parameters (dispersion, length, effective area) selected to maintain operation within a “small gain” regime while also extending the long wavelength edge of the gain bandwidth and reducing the gain ripple attributed to the EDFA component.
Claims24
A fiber-based C-band optical amplifier comprising:
- an erbium-doped fiber amplifier (EDFA) module operating at a highly inverted level, the EDFA module including a section of erbium-doped optical fiber and a first laser pump source for supplying pump light with a power level sufficient to achieve a high inversion level, wherein one or more optical input signals propagating at wavelengths within the C-band spectral range through the EDFA module are amplified by the presence of pump light;
- and
- a discrete Raman amplifier (DRA) module including a section of optical gain fiber for receiving as an input one or more optical signals propagating at wavelengths within the C-band range and a second laser pump source for supplying pump light to the section of optical gain fiber, the section of optical gain fiber having a length selected to maintain operation in a small gain regime of less than 7 dB, wherein a combination of the EDFA module and the DRA module provides a gain bandwidth of at least 42 nm within the C-band wavelength range of 1525-1573 nm.
A method of amplifying optical signals propagating at wavelengths within a wavelength range of 1525-1573 nm, the method comprising:
- applying multiple optical input signals operating in the wavelength range of 1525-1573 nm as an input to a discrete Raman amplifier (DRA), the DRA configured to exhibit a tilted gain profile with increasing gain for longer wavelengths, no greater than 6.6 dB for a long wavelength edge of 1573 nm and an average gain no greater than 4 dB for the complete C-band wavelength range;
- providing amplified optical output signals as a small gain regime output from the DRA, the amplification following the tilted gain profile;
- and
- applying the amplified optical output signals from the DRA as an input to an erbium-doped fiber amplifier (EDFA) operating at an inversion level of at least 0.69, the combination of the DRA and EDFA creating a gain bandwidth of at least 42 nm within the C-band range.
Dependencies are inferred from the claim text.