Optical Fiber Amplifiers Research Articles

Domestic and international development trends of broadband fiber amplifier

In this era of information explosion, the improvement of communication capacity has become an urgent problem, and the improvement of transmission speed and the reduction of channel spacing are near the limit, so widening the available bandwidth of fiber optic transmission is the most feasible method. The research progress of fiber optic amplifiers is analyzed, and the outlook is presented. Researchers are working to find breakthroughs in C++ band, L++ band, and C+L band, starting with amplifiers materials, structures, and designs. The EDFA targeted C++ and L++ band have been widely studying these years while different types of amplifiers have been invented to simultaneously work on C+L band. Also, as quantum dot is introduced to design innovated fiber amplifier, more new amplifiers need to be invented to achieve better amplification. This paper presents the recent research results of the above-mentioned research directions, and the next goal of researchers is to stabilize all these amplifiers gain flatness and production implement ability.

Ppb-level methane detection sensitivity based on a homemade Raman fiber amplifier and differential photoacoustic technology.

A high-power near-infrared wavelength-modulated differential photoacoustic spectroscopy sensor for parts-per-billion (ppb) level methane detection is reported by using a homemade Raman fiber optical amplifier. A commercial 1653.7nm continuous wave distributed feedback laser is employed as a seed source to excite a high light power of ∼550m W, which greatly improves sensor performance. Wavelength modulation spectroscopy and differential techniques are applied to further improve the signal-to-noise ratio of the photoacoustic signal. A 1σ minimum detection limit of ∼10p p b for methane detection is achieved with an integration time of 10s.

Structural, optical, and magnetic studies on novel Pr- doped barium lithium fluoroborate glass system

The current study involves the spectral analysis of barium lithium fluoroborate glasses doped with Praseodymium Oxide (Pr6O11). The glass composition used in the study is (70-x) B2O3+20BaF2+10Li2O+xPr6O11 (where x = 0.0, 0.5, 1.0, 1.5 and 2.0 mole%) and was prepared using the traditional melt quenching technique. The amorphous nature of the prepared glasses was confirmed by the X-ray diffraction spectrum. The Raman spectroscopy demonstrated that the addition of Pr6O11 to the barium lithium fluoroborate glasses caused structural changes. The thermal analysis confirmed that Pr6O11 doping increases glass transition temperature and enhances glass thermal stability. The optical characteristics of the glasses that were prepared were analyzed through the use of UV, Vis, and NIR absorption. The calculation of the optical bandgap for both direct and indirect allowed transitions was conducted in order to gain insight into the electronic band structure, as well as to determine the Urbach energy values. The investigation includes an analysis of the refractive index and extinction coefficient across the whole range of wavelengths. The magnetic behavior of all samples was observed to be soft ferromagnetic. The glass material's ability to provide windows for optical fiber at a wavelength of 1550 nm suggests its potential as a viable source for waveguide lasers and its appropriateness for use in applications involving optical fiber amplification.

Backward pumped distributed Raman amplifier: enhanced gain

The backward Raman amplifier (RA) can considered as one of the best solutions for optical communication, especially in Wavelength Division Multiplexing technology. They reduce the nonlinear effects, have low noise figure and a wide frequency range. The work in this paper aims to reduce the attenuation of optical signal due to its propagation optical fiber and increase both amplifier gain and output signal power. Two backward Raman models are proposed. Proposal one model consists of two cascaded RAs and the other (proposal two) consists of three cascaded RAs. Three backward pump power levels 200, 400, and 600 mW are used to simulate the models with the three types of fibers: single-mode fiber, Truewave, and Freelight, at an amplifier length of 100 km. Proposal two achieves a maximum gain of 31 dB at 600 mW pump power 600 mW using Truewave optical fiber, with 27.7 dBm maximum output signal power. This proposal is evaluated showing 11.15% gain enhancement and 200 mW saved power when compared to previously published work.

The role of tungsten oxide in Er3+-doped bismuth-germanate glasses for optical amplification in L-band

A series of novel Er3+-doped bismuth-germanate glasses containing different tungsten concentrations with a molar composition of 97.5[(75 − x)GeO2–25Bi2O3–(x)WO3]–2Sb2O3–0.5Er2O3 (x = 5, 10, 15, 20, and 25 mol%) were fabricated. Their thermal properties are measured by differential scanning calorimetry. A structural investigation by Raman spectroscopy suggested that changes occurred in the glass network by WO3 incorporation. By laser excitation at 980 nm, a strong emission from Er3+ ions at 1532 nm is observed, while the WO3 addition caused changes in the emission spectra. The emission cross-section spectra of Er3+ are calculated by both McCumber and Füchtbauer–Ladenburg theories and their comparison showed these theories yielded slightly different results, but in both cases, the calculations showed that a gain signal in L-band can be achieved when 30% of the Er3+ ions are at the excited state. This study proves that the Er3+-doped bismuth-germanate glasses are suitable for optical fiber amplifier applications operating at C- and L-band.

Efficient structural manipulation of PbS in Er-doped silica optical fibers for enhanced amplification systems

In active silica optical fibers, improving the solubility and uniformity of non-concentration-quenching luminescence centers is a key strategy to achieve high gain fiber amplifiers. Herein, we report a novel Er-doped silica optical fiber (EDF) modified by PbS semiconductor incorporation for the first time. Owing to the bridge role of PbS, Er2O3 nanofilms deposited on the substrate via atomic layer deposition (ALD) have porous and loosely layered network structures with an increasing number of ALD-PbS layers. Subsequently, during the high-temperature fiber preparation process, this loose porous structure aids the dissolution and provides an optimal local environment of Er3+ ions in the silica matrix. As a result, the maximum phonon energy of the silica network for PbS/Er co-doped silica optical fiber (PEDF) is reduced, resulting in an increase of the Er3+ ion fluorescence lifetime, approximately 11.455 ms. Furthermore, we achieved 34 dB maximum gain of PEDF sample with the lowest noise figure of 3.9 dB at 1.5 μm. The gain bandwidth over 20 dB of PEDF is approximately 46 nm, which is nearly 44% higher than that of EDF. These results indicate that the PEDF prepared by structural manipulation has great potentials in optical fiber amplifier and laser applications.

Dual Polarization DQPSK ROF System with Duo Binary Precoding and Hybrid Amplification for Effective Hybrid SMF FSO Transmission Medium

This article demonstrates the utilization of a hybrid amplification technique on the transmission part of the proposed hybrid medium transmission system which includes both using Single Mode Fiber (SMF) with 60 km and Free Space Optic (FSO) with a range between 5 km and 25 km. It has included four weather situations with an investigation of the FSO medium-based system performance. The system uses 64 channels based on Dual Polarization-Differential Quadratic Phase Shift Keying (DP-DQPSK) Dense Wavelength Division Multiplexing (DWDM) for the Radio over Fiber (RoF) system using the Duo Binary coding scheme to improve the system efficiency in general and the cross-talk in particular. The investigations will include using the hybrid amplifiers of Erbium Doped Fiber Amplifier (EDFA) and Optical Amplifier (OA) for transmission. The analysis results show that using the hybrid amplification could improve the transmission to reach 25 km for light air case, meanwhile, for light haze, it could reach up to 20 km. Moderate haze could improve transmission efficiency for a distance of 7 km. Finally, for moderate rain situations, the transmission could be further improved to cover a distance of up to 5 km.

Modeling and numerical simulation of the gain spectrum of Thulium-doped broadband fiber amplifiers

Nowadays, due to the complex signal medium conversion process of semiconductor laser amplifiers, the optical fiber amplifier, which is a new type of all-optical amplifier, is increasingly used in optical fiber communication lines for signal amplification because it can directly perform all-optical amplification of signals and are especially suitable for relay amplification of long-distance optical communications. Our research project is the gain spectrum of the Thulium-doped broadband fiber amplifier. The signal wavelength range is from to . The goal is to obtain the gain spectrum with fiber length variation, doping concentration, and pump power. This paper follows a logical order that presents the introduction, the formulas used in the experiment, and the result and analysis. According to the output wavelength range, energy level structure, and electronic transition process, we designed the pump wavelength and established the rate and power propagation equations. Eventually, gain spectrum with a variation of fiber length, doping concentration, and pump power is available using MATLAB for programming and calculating. With our research achievement, a more efficient optical fiber amplifier is possible to be made in the future.

Near-infrared sensitive differential Helmholtz-based hydrogen sulfide photoacoustic sensors.

A near-infrared (NIR) sub-ppm level photoacoustic sensor for hydrogen sulfide (H2S) using a differential Helmholtz resonator (DHR) as the photoacoustic cell (PAC) was presented. The core detection system was composed of a NIR diode laser with a center wavelength of 1578.13 nm, an Erbium-doped optical fiber amplifier (EDFA) with an output power of ∼120 mW, and a DHR. Finite element simulation software was used to analyze the influence of the DHR parameters on the resonant frequency and acoustic pressure distribution of the system. Through simulation and comparison, the volume of the DHR was 1/16 that of the conventional H-type PAC for a similar resonant frequency. The performance of the photoacoustic sensor was evaluated after optimizing the DHR structure and modulation frequency. The experimental results showed that the sensor had an excellent linear response to the gas concentration and the minimum detection limit (MDL) for H2S detection in differential mode can reach 460.8 ppb.

Fabrication and characterization of tapered photonic crystal fiber for broadband 2 µm: four-wave mixing-based fibered OPCPA

We present the simulation, fabrication, and characterization of large area microstructured fiber tapers which enables broadband phasematching conditions of the four wave-mixing process. These silica-based tapers are intended to serve as a nonlinear gain medium for intense and high average power Fiber Optical Parametric Chirped Pulse Amplifier emitting at 2 upmu hbox {m} and strongly pumped at Yb wavelength. Different geometries (tapered/untapered, aspect ratio, etc.) are fabricated, analyzed and their broadening properties—key for supporting ultrashort pulses amplification—are compared and discussed. The characterization of nonlinear gain bandwidth of the tapers relies on a tunable source of stochastic pulses based on tunable amplified spontaneous emission in Yb-doped amplifiers. The strong overshoots of this source allows degenerate four-wave mixing process to occur thus generating broadband incoherent visible signal and mid-infrared idler waves at much lower average power than usually needed with coherent pumping. The idler centered around 1.85 mum is broadened due to zero-dispersion wavelength shift along the taper.

Cubic-Shaped and Rod-Shaped YPO4 Nanocrystal-Doped Optical Fibers: Implications for Next Generation of Fiber Lasers

Engineering silica optical fibers by nanoparticle doping is a promising technology that allows the introduction of new functionalities and extends their applicable fields. However, the knowledge gap about the impact of the extreme fabrication temperatures on the nanoparticle features prevents field progress. Herein, we demonstrate that the particularities of fiber fabrication, such as fast-heating rates and quenching heat treatments, can be leveraged to explore unlikely phenomena at the nanoscale under standard laboratory conditions. Tetragonal cubic-shaped and monoclinic rod-shaped YPO4 nanocrystals are in situ nucleated in a silica-based fiber core glass, slightly modified with Ge and P, which shows for the first time, the possibility of doping optical fibers with this type of nanostructures, in terms of shape, composition, and structure of the nanocrystals. Structural and anisotropic differences allow engineering differently their shape and composition in the fiber core by tailoring the drawing temperature, as revealed by a thorough study consisting of scanning electron microscopy (SEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), electron energy loss spectroscopy (EELS), and high-resolution transmission electron microscopy (HRTEM). This work demonstrates, for the first time, the possibility of doping optical fibers fabricated by modified chemical vapor deposition (MCVD) with anisotropic nanostructures, as well as the stability of the monoclinic YPO4 phase. These findings open up new avenues to study shape-dependent properties of rare-earth orthophosphate (REPO4) nanostructures in optical fibers which will allow incorporating unprecedented functionalities and will have an impact in several fields of application, such as fiber lasers and optical fiber amplifiers, among others.

Periodic and solitary waves generating in optical fiber amplifiers and fiber lasers with distributed parameters

We study self-similar dynamics of picosecond light pulses generating in optical fiber amplifiers and fiber lasers with distributed parameters. A rich variety of periodic and solitary wave solutions are derived for the governing generalized nonlinear Schrödinger equation with varying coefficients in the presence of gain effect. The constraint on distributed optical fiber parameters for the existence of these wave solutions is presented. The dynamical behaviour of those self-similar waves is discussed in a periodic distributed amplification system. The stability of periodic and solitary wave solutions is also studied numerically by adding white noise. It is proved by using the numerical split-step Fourier method that the profile of these nonlinear self-similar waves remains unchanged during evolution.

Hybrid Raman/EDFA optical fiber amplifiers configuration in amplified ultra wide band wavelength division multiplexed systems

Abstract This paper presented the hybrid Raman and erbium doped fiber amplifiers in amplified wavelength division multiplexed systems. Important role of singly and hybrid light amplifiers are clarified in the presented work. EDFA/RAMAN based average power model based Raman amplifiers are used for strength the signal power levels. CW laser with return to zero code are employed in amplified multiplexed systems. The optimum EDFA optical amplifiers length is used to strength the signal through the optical fiber channel. The max. signal quality and min. error rates are obtained with the presented model. By the assistance of multi pumped lasers for the flat gain in the hybrid EDFA/Raman light amplifiers.

Spectral Analysis and Gain Modeling and Numerical Simulation of Bismuth-doped Fiber Amplifier

Fiber optic amplifier is an important component of fiber optic communication and the use of the properties of rare earth ions to dope the fiber core is an important way to obtain greater amplification and reduce loss. Because of the unique light-emitting properties of Bismuth ions, the Bismuth doped fiber amplifier (PDFA) has a wide range of applications in the field of fiber amplifier. This paper focuses on the spectral analysis of Bismuth-doped ( ) fiber amplifiers under different parameters by referring to the absorption spectrum of . And the energy level structure of was selected for a wide range of amplification windows → pumping scheme corresponding to the pumping wavelength of 950 nm, and the rate propagation equation and power transmission equation were established based on the previous work. The numerical simulations were also carried out by MATLAB programming. The effects of doping concentration, fiber length, and pump power on gain, noise index, and output power were analyzed and summarized by MATLAB plotting. In the future, researchers can use neural network algorithms to obtain the combination of Bismuth-doped fiber amplifier parameters that will achieve maximum gain, thus enabling advances in information transmission rates and distances in real-world communications.

The design modeling and numerical simulation of a Bismuth-doped glass fiber amplifier

At present, the main communication window of fiber amplifier is in C-band ( ), and the amplification technology in O-band ( ) needs to be improved. The optical fiber amplification technology of band is studied in this paper. Based on three different Bismuth-doped glass materials, the design modeling and numerical simulation are carried out, and the corresponding amplification bands are , and . The rate equation and transmission equation of the three-level transition model in steady state were established. The gain, the power of pump, the power of signal and ASE signal power of the three bands were simulated by MATLAB, and the material with the best performance was further analyzed. The results show that signal light has the best amplification effect, and the maximum gain is when the fiber length is . It is also found that the optical fiber length required to achieve the optical signal optical gain with the pump power is positive correlation, and with the doping concentration is negative correlation, which are complementary to each other. This conclusion has important significance for the design of bismuth-doped optical fiber amplifier.

(INVITED) Bi-doped optical fibers and fiber amplifiers

Bismuth (Bi)-doped aluminosilicate, phosphosilicate, germanosilicate and high (⩾50 mol%) germanosilicate fibers have shown luminescence around 1.15 μm, 1.3 μm, 1.45 μm and 1.7 μm, respectively. Bi-doped fibers have paved the way for developing optical amplifiers and fiber lasers in the wavelength region of 1150–1500 nm and 1600–1700 nm, where it can serve a wide range of applications in astronomy, imaging, medicine and advanced optical communications. However, spectroscopic study is required to understand the nature of near-infrared (NIR)-emitting Bi active centers (BACs) to improve the efficiency of Bi-doped fiber amplifiers and lasers. In this paper, we review the luminescence properties of Bi-doped glasses as well as Bi-doped fibers with aluminosilicate, phosphosilicate, and germanosilicate glass hosts. Absorption and emission cross-sections of Bi-doped phosphosilicate fibers are reported. In addition, we review the current state of the art of Bi-doped fiber amplifiers development in the second telecom window (O-band) and in the E-band and S-band for the next-generation high-capacity optical communications.

Optical fiber signal strength based on Raman optical amplifiers schemes in dense wavelength multiplexed communication systems

Abstract This study has clarified the optical fiber signal strength based on Raman fiber optic amplifiers schemes in dense wavelength multiplexed communication systems. The signal power with, without Amplification in various pumping configurations scheme is studied with propagation distance variations. The bidirectional pumping power configuration based various pump power is analyzed with propagation distance variations. Amplified forward signal power for various fiber types is investigated with propagation distance variations. These fibers are used such as single mode (SM)-28 fiber, non-zero dispersion shifted fiber (NZDSF), truewave reach fiber for the efficient employment in fiber systems. Amplified bidirectional signal power for various both pump power and fiber types are clarified with propagation distance variations. The pumping power configurations scheme variations are demonstrated with propagation distance variations. Forward/backward pumping power configuration direction variations are investigated and clarified with propagation distance variations for various pumping power values.

400Gb/s real-time coherent PON based on a silicon photonic integrated transceiver.

We experimentally demonstrate the real-time 100/200/400 Gb/s/λ coherent passive optical networks (PONs) based on silicon photonic integrated transceiver. We investigate different configuration schemes of coherent PONs including: (1) using a Erbium doped optical fiber amplifier (EDFA) as a booster at the transmitter side; (2) using a semiconductor optical amplifier (SOA) as a booster at the transmitter side; (3) using EDFA at the transmitter side and a pre-amplified SOA at receiver side; (4) using an SOA at the transmitter side and an SOA at the receiver side. The performance of these schemes for different data rates of downstream transmission is evaluated, and the appropriate choices under different circumstances are analyzed. The real-time experimental results indicate that the EDFA can be replaced by SOA as a booster at the transmitter side in 100/200 Gb/s/λ coherent PON based on the dual-polarization QPSK (DP-QPSK) scheme with a small performance penalty. In dual-polarization a 16 quadrature amplitude modulation (DP-16QAM) 400 G/s/λ PON system, EDFA booster is preferred because an SOA introduces more nonlinearity for the 16QAM scheme. The power budget of 32.5 dB is achieved for 400 Gb/s/λ coherent PON after the 20 km standard single mode fiber (SSMF) transmission under the soft-decision feedforward error correction (SD-FEC) threshold.

Different mode operations based all optical fiber amplifiers with optical differential polarization quadrature phase shift keying transmitter

Abstract This paper simulated the different mode operations based all optical fiber amplifiers with optical differential polarization quadrature phase shift keying transmitter. Gain mode operation, power mode operation and saturation mode operation based all optical fiber amplifiers are employed to measure the signal power, noise power level at both spectral time domain and frequency domain. The peak signal power and signal power amplitude are accurately measured for different mode operations based all fiber optical amplifiers. The performance is enhanced with saturation mode operation based all optical fiber amplifiers.

Solid-State Fiber Laser of the Yellow Spectral Range on the Rhodamine 6G Dye with an Optical Fiber Amplifier for the Formation of Sodium “Laser Guide Stars”

Solid-State Fiber Laser of the Yellow Spectral Range on the Rhodamine 6G Dye with an Optical Fiber Amplifier for the Formation of Sodium “Laser Guide Stars”