Erbium-doped Optical Fiber Amplifier Research Articles

High-Sensitivity Differential Helmholtz Photoacoustic System Combined with the Herriott Multipass Cell and Its Application in Seed Respiration.

A highly sensitive photoacoustic detection system using a differential Helmholtz resonator (DHR) combined with a Herriott multipass cell is presented, and its implementation to sub-ppm level carbon dioxide (CO2) detection is demonstrated. Through the utilization of erbium-doped optical fiber amplifier (EDFA), the laser power was amplified to 150 mW. Within the multipass cell, a total of 22 reflections occurred, contributing to an impressive 33.6 times improvement in the system sensitivity. The normalized noise equivalent absorption coefficient (NNEA) was 8.64 × 10-11 cm-1·W·Hz-1/2 [signal-to-noise ratio, (SNR) = 1] and according to the Allan variance analysis, a minimum detection limit of 500 ppb could be achieved for CO2 at 1204 s, which demonstrates the long-term stability of the system. The system was applied to detect the respiration of rice and upland rice seeds. It is demonstrated that the system can monitor and distinguish the respiration intensity and respiration rate of different seeds in real time.

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.

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.

Characterization and Application of Solitons in a High Nonlinearity Optical Link with Dense Wavelength Division Multiplexing (DWDM) and Ultra-Dense Wavelength Division Multiplexing (UDWDM) Technics

The constantly growing needs in terms of speed and bandwidth, especially all services using data has become greedy. Today optical fiber is the medium of choice for many advantages over others channels. although the optical fiber has taken the label of transmission channels, we won’t be able to do without its nonlinear character and dispersions, which are part of the major problems during optical transmission. In this article, we are presenting the use of optical solitons in the fiber optic link, with a particular way; we have considered two kind of links, the underground one and the overhead one, in the first link, we have applied optical soliton in order to just take into account the optical Kerr effect. And for the overhead link, we can transmit for short distance by using the return to zero modulation’s format and the use of optical Erbium Doped Fiber Amplifiers (EDFA). The solitons which are the impulses, capable of propagating in the nonlinear optical fiber and dispersive without any distortion; to justify our hypothesis, we compare a dense wavelength division multiplexing (DWDM) without soliton and the dense wavelength division multiplexing with solitons; we notice that, the link with soliton is better than the first because the pulse keeps its shape from the source up to the destination, its eye diagram is opened which means there is no much noises. After the simulations in Matlab and optisystem software, we went to Congo telecom, to do our test with the optical time-domain reflectometer (OTDR), for both installations. From that study while transmitting over 100km it is better to use optical solitons with the high speed.

Performance study of randomly coupled erbium-doped fiber amplifier using machine learning

This study describes the performance of a randomly coupled erbium-doped optical fiber amplifier (EOFA) using machine learning. A reinforcement learning-based artificial neural network (RL-ANN) is used to study various parameters of EOFA, such as gain, noise figure, and inter-core crosstalk for the 12-core EOFA. In addition to this, the relationship between mode-dependent loss, a penalty of the EOFA, and the average bending loss (BL) for three operating wavelengths, such as 1550, 1580, and 1600 nm, has been studied. To predict the performance of RL-ANN, three different machine learning algorithms, namely, K-nearest neighbor (KNN), ANN, and support vector machine (SVM) are used. The performance of the proposed RL-ANN is evaluated using five statistical error criteria: mean absolute error, root mean square error, scatter index, coefficient of variation, and overall index measurement. The statistical test result shows that the proposed RL-ANN provides the best performance compared to KNN, ANN, and SVM. The performance of the RL-ANN-based erbium-doped fiber amplifier (RA-EOFA) is studied and the results show that the gain and estimated NF based on a wavelength range from 1555 to 1565 nm provides a maximum gain. A comparison study was carried out for the proposed RA-EOFA with other learning methods. The results show that the proposed RA-EOFA provides the best performance in terms of less BL (0.25 dB), mode-dependent loss (0.5 dB), computational time (36.8 s), and a success rate of 98.39%.

Impact of coupling topology upon noise robustness of small optical reservoirs

In this work, we perform the numerical investigation of the performance of the small optical reservoir computing (RC) systems with four neurons using the commercial software for optical fiber communication system. The small optical RC system consists of the components of the optical fiber communication. The nonlinear function which is required in RC is provided by the erbium-doped optical fiber amplifiers (EDFA). We demonstrate that the EDFA should be operated in the saturated or non-linear regime to obtain a better performance of the small optical RC system. The performance of the small optical RC systems for different topological neuron structures is investigated. The results show that the interconnection between the neurons could offer a better performance than the systems without interconnection between the neurons. Moreover, the input signals with different noise levels are launched into the systems. The results show that the small optical RC system can classify the noisy input optical waveforms even when the signal-to-noise ratio is as low as − 2.55 dB.

Simulation solution for single and cascaded multi-wavelength Brillouin fiber lasers based on an analytical model

Abstract Here we propose a simulation model based on a previously reported analytical description of the Brillouin gain, that takes into account pump depletion, which allows us to make very accurate calculations for Brillouin fiber lasers (BFLs) working both in a single and cascaded multi-wavelength configurations. Output powers and conversion efficiencies are analyzed and compared with experimental results for various lasers setups using 25 km of a non-zero dispersion-shifted fiber (NZDSF) as the Brillouin gain media. In our experimental investigations, we used a pump laser at 1565 nm, with a bandwidth of 1 kHz, and output powers varying from 0 to its maximum value of 14 mW. We analyzed the laser behavior under various conditions using output couplers with output ratios varying from 10% to 90%, and to generate the cascaded Brillouin laser we have used a 10 m Erbium-doped optical fiber amplifier as a gain block in a separated cavity. Additionally, a spectral reconstruction is made based on power predictions of our model for the cascaded BFL with excellent agreement with experimental data.

Suppression of stimulated Brillouin scattering in pulsed erbium-doped fiber amplifier through intensity-modulated counter pumping

We suppress stimulated Brillouin scattering in an erbium-doped optical fiber amplifier for 50-ns-long transform-limited signal pulses by counter-directional pumping with a pulse burst. The pump pulse burst is codirectional with the parasitic Brillouin Stokes wave, which, therefore, undergoes cross-phase modulation and thus spectral broadening due to the intensity-modulated pump. The broadening inhibits its growth. We experimentally study the effect of pump pulse parameters and improve the SBS threshold by up to 4 dB when amplifying signal pulses at a wavelength of 1565 nm with pumping at 1536 nm.

Simultaneous measurements of distributed temperature and discrete strain based on Hybrid Raman/FBG system

A hybrid optic fiber system is proposed and experimentally demonstrated, which combines the Raman-based distributed temperature sensing (DTS) and high-reflective fiber Bragg grating (FBG) sensors for discrete static strain measurement along the same sensing fiber. A distributed feedback laser (DFB) is adopted to generate stimulated emission (STE) light pulses for demodulation of optical time domain reflectometry (OTDR) technology, and an erbium-doped optical fiber amplifier (EDFA) is utilized to increase the power of laser and produce spontaneous emission (SPE) lights. Thus the STE light is employed as pump light for temperature demodulation through Raman-based DTS, as well the SPE lights can be used for discrete strain demodulation through wavelength division multiplexing of FBGs. Since the central wavelengths of FBGs are far away from the lasing wavelength of the laser, the FBG-induced insertion loss can be negligible, therefore the lights reflected by FBGs have little influence on the performance of DTS system. The strain information can be obtained through deducting the temperature induced wavelength shifts of FBGs, since the temperature information can be achieved by DTS system in advance. The experimental results show the maximum measurement error of temperature and strain are 0.48 °C and 10.47 με, respectively. This hybrid system indicates an effective improved multiplexing scheme based on the Raman-based DTS for simultaneous measurements of distributed temperature and discrete static strain, and a better solution of cross sensitivity problem in FBGs.

Design of a Multi Mode Interferometer using LC:PDMS technology

Multimode interference (MMI) couplers have received more attention in recent years due to their significant role played in telecommunications. Their unique features are compactness, relaxed design constrains, large optical bandwidth. In this paper a theoretical analysis and design of a MMI acting as multi/demultiplexer based on liquid crystals (LC) embedded in polydimethylsiloxane (PDMS) channels named LC:PDMS waveguides is presented. Such a device is capable of operating at two different wavelengths, typically used in erbium-doped fiber optical amplifiers, 980 and 1550 nm with an extinction ratio higher than 11 dB. The LC:PDMS MMI operation is tuned by applying an electric field by using coplanar electrodes whose fabrication process is described.

151-km single-end phase-sensitive optical time-domain reflectometer assisted by optical repeater

A phase-sensitive optical time-domain reflectometry (ϕOTDR) system that can detect intrusion over 150 km is presented. The ϕOTDR system uses nonbalanced optical repeaters to extend the sensing distance. The repeater consists of two erbium-doped optical fiber amplifiers (EDFAs) and one Raman amplifier (RA). One EDFA power amplifier amplifies the forward-transmitting pulse, and one EDFA preamplifier is used for the backscattering signal, respectively. The RA helps keeping the power along the fiber stable. The optical repeater is installed at the connection of two adjacent fibers to compensate the power decline due to fiber loss. It is easy to install the repeater midway among the fiber links in the system for longer-distance sensing since there is no need of modifying the original sensing system. The theoretical analysis of the repeater is given to describe its effect on the distributed sensing. In experiments, several ϕOTDR traces show a good agreement with theoretical results. Using the optical repeater, 35-Hz vibration at 151 km is successfully measured with signal-to-noise ratio of 8 dB without extra signal processing.

Simulation of a long-haul fiber optic link with a two-mode optical fiber

Modern telecommunication networks approach the capacity crunch, which is associated with the so-called nonlinear Shannon limit. So, the passage to fiber optic links with few-mode optical fibers is considered as an alternative solution of the described problem concerned with high nonlinearity of conventional commercial single-mode optical fibers. Presently, various designs of few-mode optical fibers have been known, with the recently published works presenting experimental results demonstrating their potentialities for long-haul fiber optic links. A lot of models of long-haul fiber optic links with few-mode optical fibers have been developed based on which features of a few-mode optical fiber transport network were numerically simulated. This work presents the results of simulation of a 6000-km long-haul fiber optic link with a two-mode optical fiber and 100-km-per-span Erbium doped fiber optic amplifiers system under 100 Gbps DP-DQPSK data transmission. We studied the use of particular linearly polarized modes and optical vortices for signal transmission. The computation results were compared with the simulation of the same fiber optic link with a single-mode optical fiber under the identical conditions.

Simplex-method based transmission performance optimization for 100G PDM-QPSK systems with non-identical spans

A simplex-method based optimizing (SMO) strategy is proposed to improve the transmission performance for dispersion uncompensated (DU) coherent optical systems with non-identical spans. Through analytical expression of quality of transmission (QoT), this strategy improves the Q factors effectively, while minimizing the number of erbium-doped optical fiber amplifier (EDFA) that needs to be optimized. Numerical simulations are performed for 100Gb/s polarization-division multiplexed quadrature phase shift keying (PDM-QPSK) channels over 10-span standard single mode fiber (SSMF) with randomly distributed span-lengths. Compared to the EDFA configurations with complete span loss compensation, the Q factor of the SMO strategy is improved by approximately 1dB at the optimal transmitter launch power. Moreover, instead of adjusting the gains of all the EDFAs to their optimal value, the number of EDFA that needs to be adjusted for SMO is reduced from 8 to 2, showing much less tuning costs and almost negligible performance degradation.

Evolution of EDFA from single-core to multi-core and related recent progress in optical communication

A compact 1.48 μm InGaAsP laser-diode (LD)-pumped erbium-doped optical fiber amplifier (EDFA) was invented in 1989 and it revolutionized optical communication in combination with a wavelength division multiplexing (WDM) technique. Recently, in addition to the existing single-core EDFA, a multi-core EDFA, which employs space division multiplexing (SDM), was developed to increase transmission capacity even further. The first half of this paper describes the evolution of the EDFA from a single-core to a multi-core device and the second half focuses on related topics in optical communication.

Novel optical packet switching scheme using OFDM label with one core router and two edge routers

In this paper, we propose and experimentally demonstrate a novel optical packet switching scheme with one core router and two edge routers, in which an orthogonal frequency division multiplexing (OFDM) signal is generated as a label. In this experiment there are two transmission spans, each span consists of 50-km SMF-28 and an erbium-doped optical fiber amplifier (EDFA) without dispersion management. A 10Gb/s on-off keying (OOK) optical payload and a 2.5Gb/s OFDM optical label are generated, encapsulated, and transmitted in the first span. And then old label is replaced by new label, the generated new optical packet after transmission over the second span is detached and detected. The transmission performance of the optical label and payload is experimentally investigated at the ingress router, core router and egress router.

Slowdown of group velocity of light pulse in erbium-doped optical fiber amplifier under no absorption loss at a room temperature

Because of the absorption of erbium-doped optical fiber, the group velocity of the optical pulse propagation is slowed down and the intensity of signal is reduced, which brings more difficulties to the actual measurement of slow light and its application in communications, such as the distortion and the low measurement.Therefore only after the group velocity slowdown of light pulse in erbium-doped optical fiber under no absorption loss is realized, can the slow light technology really have the practical application. We investigate the erbium-doped optical fiber amplifier deeply and develop a technology, in which the different pump powers and fiber lengths are used to reduce the signal loss through theoretical calculation and realize the group velocity slowdown of light pulse. The results show that no absorption loss is realized at a pump power of 3.5 mW, and we realize the slow light with a fiber length of 0.1 m when the pump power is zero.

The fabrication of Er3+/Ce3+ co-doped tellurite- bismuth glasses and the improvement of spectroscopic properties

A series of 80TeO2-10Bi2O3-10TiO2-0.5Er2O3-xCe2O3 (x=0, 0.25, 0.5, 0.75, 1.0 mol%) and (80-y) TeO2-10Bi2O3-10TiO2-yWO3-0.5Er2O3-0.75Ce2O3 (y=3, 6, 9, 12 mol%) tellurite-bismuth glasses are prepared by the conventional high-temperature melting and annealing method. The absorption spectra of 400-1700 nm, upconversion spectra and 1.53 m band fluorescence spectra under the excitation of 975 nm, the 4I11/2 and 4I13/2 level fluorescence lifetimes of Er3+ under the excitation of 808 nm, and the Raman spectra of doping-free glass samples are measured. Meanwhile, the spectroscopic parameters of Er3+ are calculated and analyzed with the help of Judd-Ofelt theory and McCumber theory. The results indicate that the upconversion fluorescence can be suppressed efficiently and the 1.53 m band fluorescence can be enhanced evidently, owing to the energy transfer from Er3 +: 4I11/2Ce3+:2F5/2 levels when the Ce3+ ions are introduced into the Er3+-doped tellurite-bismuth glasses. Moreover, the 1.53 m band fluorescence intensity can be improved and the fluorescence spectral width can be broadened further when an appropriate amount of WO3 component is introduced. The above research results are of theoretical significance for obtaining the tellurite-bismuth glasses with excellent spectroscopic properties, which are used for the 1.53 m broadband Erbium-doped optical fiber amplifier.

Accurate computations of the nonlinear phase noise and BER in DPSK modulation-balanced direct detection high-speed optical fiber communication systems

This article analyzes the nonlinear phase noise caused by an amplified spontaneous-emission of erbium-doped optical fiber amplifier and self-phase modulation (SPM) in a differential phase-shift keying modulation- balanced direct detection optical fiber communication system. Using numerical methods, the characteristic function of the differential nonlinear phase noise \({\cos (\Delta \varphi)}\) in the received electrical current of signals and the accurate computation formula of the BER are achieved when SPM is dominant comparing to cross phase modulation and four wave mixing. The result is verified by a simulation of a 40-Gbit/s transmission system.

Broadband amplitude-modulated laser source with high output power for FM/cw lidar transmitter

We are building a long-range FM/cw nonscanning imaging lidar breadboard. This lidar system achieves ranging based on a frequency modulation/continuous wave (FM/cw) technique, implemented by an amplitude modulated mid-IR diode laser transmitter with a linear frequency modulation (LFM) of the subcarrier. Firstly, various schemes of light beam modulation are analyzed. Secondly, we put forward a laser modulation scheme whose core was formed by a 1.55 μm electro-absorption modulated laser diode (EML) and an erbium-doped optical fiber amplifier (EDFA), then a corresponding experimental system architecture and components for light beam modulation and detection are established. Finally, a corresponding experiment of laser beam modulation is completed for the first time. In our experiment, the EML amplitude is modulated by a 200 MHz to 800 MHz LFM signal, whose amplitude value is 2.05 V. The average output power of the modulated laser obtained in the experiment is 10 W, peak power is 16.4 W, and the average modulation depth is 78%. The results of tests predict that this laser modulation scheme is likely to improve the imaging range of the FM/cw lidar.

Near-Ballistic Unitraveling-Carrier Photodiode-Based V-band Optoelectronic Mixers With Low Upconversion Loss and High Operation Current Performance Under Optical IF Signal Injection

We demonstrate near-ballistic unitraveling-carrier photodiode (NBUTC-PD)-based V-band (50-75 GHz) optoelectronic (OE) mixers which can upconvert the V-band optical local-oscillator (LO) and intermediate-frequency (IF) signals. The optical LO and IF signals share a single erbium-doped optical fiber amplifier (EDFA) which means that the mixing performance of the device can be optimized by properly adjusting the ratio between the injected optical LO and IF power to the EDFA. The utilization of the strong nonlinearity of the ballistic transport of the electrons in the NBUTC-PD under a reverse bias regime means that our device achieves a low upconversion loss ( -6 dB) under a very high operating current (23 mA) in V-band (60 GHz). We are able to improve the operating current at the V-band over that previously reported for UTC-PD-based OE mixers. This is made possible by an increase in the optimum operating voltage from the near forward bias (0 V) to the reverse bias regime (-1.7 V).