Silica-based Erbium-doped Fiber Amplifiers Research Articles

Net gain in C+L band from LED pumped broadband emission in Er3+-doped oxyhalide tellurite glass

Expanding gain bandwidth into the L-band for erbium-doped fiber amplifiers (EDFAs) is a crucial strategy to overcome limitations in prevalent C-band focused commercial silica-based EDFAs, significantly boosting optical network transmission capacity. Herein, we synthesized Er3+-doped broadband near-infrared emission tellurite glasses utilizing the melt quenching process, systematically exploring the impact of ZnCl2 on the glass structure and optical properties. The 82TeO2–3Nb2O5–15ZnCl2–3Er2O3 (TNZ15) glass emerged as a standout candidate for broadband amplifiers around wavelength at 1.55 μm. With escalating ZnCl2 concentration, a discernible red shift in the emission peak wave lines was observed, accompanied by an expansion of the full width at half maximum (FWHM) from 98 nm to 106 nm. Noteworthy characteristics of all samples included exceptional thermal stability and elevated near-infrared (NIR) transmittance. Application of the Judd-Ofelt (J-O) theory facilitated the calculation of J-O parameter intensity, providing deeper insights into the optical behavior of the materials. Finally, the evaluation of TNZ15 planar optical waveguides, employing the vertical top pumping mode of two 980 nm LEDs, encompassed both the C-band (1530–1565 nm) and the L-band (1565–1625 nm). The results underscore the potential of TNZ15 glass as a promising gain material for broadband optical amplifiers and lasers, offering valuable insights into the development of next-generation optical amplification technologies.

Performance comparison of enhanced Erbium–Zirconia–Yttria–Aluminum co-doped conventional erbium-doped fiber amplifiers

A new Erbium–Zirconia–Yttria–Aluminum co-doped fiber amplifier (Zr-EDFA) with improved gain and noise figure characteristics is successfully demonstrated using a newly developed Erbium–Zirconia–Yttria–Aluminum Co-Doped fiber (Zr-EDF) as the gain medium. The fiber consists of Er2O3-doped ZrO2 rich nano-crystalline particles and thus it has a high erbium doping concentration with absorption pump power around 80.0dB/m at 980nm. Compared to the conventional silica based Erbium-doped fiber amplifier (Si-EDFA), the gain of the proposed Zr-EDFA is more efficient especially at longer wavelength region. At input signal of −10dBm, a flat gain of 19.5dB is obtained for the single-pass Zr-EDFA with gain variation of less than 1dB within a wavelength region from 1530 to 1570nm. In double-pass configuration, the measured gain varies from 17.5dB to 21.3dB within the wavelength region from 1525 to 1565nm, where the noise figure is maintained at below 10dB. The double-pass Zr-EDFA gain is also maintained above 12dB within a wavelength region from 1520 to 1600nm. These results indicate that the Zr-EDFA can achieve even better flat-gain value and bandwidth as well as lower noise figure than the conventional Si-EDFA

Experimental Investigation of Neutron Irradiation Effect on Silica-Based Erbium-Doped Fiber Amplifier

This paper studied the influence of neutron irradiation on the characteristics of 980nm pumped erbium-doped fiber amplifier(EDFA). After 7 days neutron irradiation, with the total fluence of 1.5×1013n/cm2, radiation induced loss changed little compared with pre-irradiation, maximum difference of single signal and WDM signal between pre-irradiation and post- irradiation are 0.5dB and 0.6dB, respectively. EDFA affected by neutron irradiation got less loss when the input signal power is higher.

Highly efficient short length Bismuth-based erbium-doped fiber amplifier

An efficient 21 cm Bismuth-based erbium doped fiber amplifier (Bi-EDFA) operating in both C- and L-band wavelength regions is proposed and demonstrated. The proposed Bi-EDFA uses the gain medium with an erbium ion concentration of 6300 ppm in conjunction with a double-pass configuration. Compared to conventional silica-based erbium-doped fiber amplifiers (Si-EDFAs) with the same amount of Erbium ions, the Bi-EDFA provides a higher attainable gain as well as a greater amplification bandwidth ranging from 1525 to 1620 nm. The proposed Bi-EDFA achieved a flat-gain of around 23 dB with gain variation of ±3.5 dB within the wavelength region from 1530 to 1565 nm at the maximum pump power of 150 mW. The corresponding noise figures are obtained at an average of 6 dB.

Study on the dynamics of a gain spectral hole in silica-based erbium-doped fiber at 77 K

A study on the dynamics of gain spectral hole burning (GSHB) in a silica-based erbium-doped fiber amplifier at 77 K was performed. When a saturation signal was input into an Er3+-doped fiber, a multigain spectral hole structure that consisted of nine gain spectral holes, was observed in the wavelength region from 1510 to 1640 nm at 77 K. As for the Er3+ ion concentration dependence of these gain spectral holes, the depth of the gain spectral hole at around 1530 nm was found to become shallower in the silica-based erbium-doped fiber that had higher Er3+ ion content. This Er3+ ion concentration dependence of the gain spectral hole depth suggests that the contribution of the energy-transfer interaction between Er3+ ions excited to the Stark levels within the ^4 I_13/2 manifold plays an important role in the gain spectral hole formation at 77 K. As far as we know, this is the first report of the Er3+ ion concentration effect on the GSHB in the Er3+-doped fiber. The dynamics of GSHB is discussed in relation to the effect of energy transfer between Er3+ ions. In addition, the relation between gain spectral hole structure and the Stark energy structure of Er3+ ion is also discussed.

Broad-band erbium-doped fiber amplifier with double-pass configuration

We demonstrate a broad-band silica-based erbium-doped fiber amplifier (EDFA) with double-pass configuration. The signal gain and noise figure are obtained more than 24 dB and less than 6 dB, respectively, for 1526-1562 nm and 1569-1605 nm. The same signal gain can be achieved with 53% less pump power and 45% shorter erbium-doped fiber length, compared to a conventional parallel type EDFA. Furthermore, the noise figure and power conversion efficiency are improved for the wavelength range.

Spectrally-efficient L-C band EDFA having a seamless interband channel region using sampled FBGs

We report a method and experimental demonstration for an L-C band silica-based erbium-doped fiber amplifier (EDFA) utilizing the entire wavelength range of both the L and C bands with no dead in between. Sampled fiber Bragg gratings (FBGs) are used to split the L and C bands, thereby providing amplification at many discrete wavelengths as well as a sharp transition between the two bands. Optical amplification with negligible power penalty is demonstrated within the interband zone using a 1.6-nm spacing between the highest C hand and lowest L band channels.

Comparative study on temperature-dependent multichannel gain and noise figure distortion for 1.48- and 0.98-μm pumped EDFAs

Temperature dependence of multichannel gain flatness and noise figure (NF) was compared for different pump wavelengths of 1.48 and 0.98 /spl mu/m on silica-based erbium-doped fiber amplifiers (EDFAs) through measurement-based numerical simulation. Owing to its temperature sensitive pump emission cross section, the 1.48-/spl mu/m pumping showed greater temperature sensitivity (maximum 0.75-dB gain flatness distortion with 0.57-dB average gain level shift, 0.3-dB NF variation for 25/spl deg/C change) than the 0.98 /spl mu/m pumping (maximum 0.5-dB gain flatness distortion with 0.015-dB average gain level shift, 0.05-dB NF variation for 25/spl deg/C change). However, it was also found that distortion ripple spectra mainly coming from the changes of signal cross sections and asymmetric gain temperature dependence necessitate compensation techniques in the EDFA link, irrespective of pump wavelength.

Long-wavelength erbium-doped fiber amplifier gain enhanced by ASE end-reflectors

We use for what we believe is the first time narrow-band end-reflectors to reduce losses through short-wavelength amplified stimulated emission (ASE) in silica-based erbium-doped fiber amplifiers operating at wavelengths above 1570 mm. The end-reflectors feed a small fraction of the ASE, up to a few tenths of a milliwatt, back into the amplifying fiber. The reflected ASE compresses the short-wavelength gain and thus reduces the ASE-losses, from, e,g., 50 mW for a launched pump power of 110 mW at 980 nm without end-reflector to 10 mW with an optimized end-reflector. We investigate possible improvements of gain (around 5 dB) and output power (up to 17 mW), and the influence of the amount and wavelength of the feedback.

Simulation of 64 x 2.5 Gb/s WDM transmission over 1056 km of standard single-mode fiber using gain-flattened silica-based EDFAs

Using computer simulation, we have shown the viability of 64 2.5-Gb/s wavelength-division multiplexing (WDM) channel transmission over 1056 km of standard single-mode fiber (SMF) using gain-flattened silica-based erbium-doped fiber amplifiers (EDFAs), long-period fiber grating filters, and dispersion compensation.

Broad-band erbium-doped fiber amplifier flattened beyond 40 nm using long-period grating filter

Broad-bandwidth amplification is essential for the construction of high-capacity multichannel communication systems. We describe a silica-based erbium doped fiber amplifier (EDFA) with a flat gain bandwidth exceeding 40 nm. The dual-stage EDFA includes a precisely designed inter-stage long-period fiber grating filter with more than 14-dB peak attenuation. By careful choice of the filter spectrum and fiber lengths, this EDFA is flat to within 1 dB over 40 nm while producing a noise figure below 4.0 dB and nearly +15-dBm output power.

1420-km transmission of sixteen 2.5-Gb/s channels using silica-fiber-based EDFA repeaters

Sixteen WDM channels each operating at 2.5 Gb/s mere transmitted through 1420 km of fiber without regeneration using silica-based erbium-doped fiber amplifiers. The amplifier spacings ranged between 96 km and 123 km. >

Gain Characteristics of Erbium-Doped Fiber Amplifiers with High Erbium Concentration

The gain characteristics of erbium-doped fiber amplifiers (EDFAs) with erbium concentrations as high as 8900 ppm have been investigated in detail with 0.98 µm and 1.48 µm pumping schemes. Although the emission cross section at 1.532 µm is 24% less than that with low erbium concentration as a result of concentration quenching, a gain as high as 24 dB was obtained with a 50 cm long fiber at a 0.98 µm pump power of 60 mW. An output power of +8 dBm was also obtained for a pump power of 60 mW at pump wavelengths of both 0.98 µm and 1.48 µm. It is concluded that the 0.98 µm pumping scheme is better than that of 1.48 µm for high concentration silica-based EDFAs.