Praseodymium-doped Fiber Amplifier Research Articles

Characterization of Visible Range Gain in Praseodymium Doped Fiber Amplifier

In the optical (380-700 nm) region, a simulation study was conducted to assess the low-signal gain, power conversion efficiency (PCE), and optical output power of a praseodymium-doped fiber optic amplifier (PDFA). The PDFA performance was assessed using the optimized Pr3+ fiber length, Pr3+ ion concentration, and pump power. Additionally, the effects of input signal voltage and amplifier gain on amplified spontaneous emission (ASE) were investigated. A lower peak signal of roughly 1 dB at 635 nm was obtained with a shorter 5 m Pr3 + doped fiber and a higher pump power of 300 mW. The impact of wavelength and pump power variations on the amplifier's optical output power's spontaneous enhanced emission (EEM) is examined. Finally, the ionic interaction (general-purpose conversion effect) in the low-power amplifier signal is analyzed by taking into account various values of the upconversion factor. Keywords: Praseodymium doped fibre amplifier, Small-signal gain, Pump power, Ultrashort laser.

Modeling and numerical simulation of the gain of a 1310nm praseodymium-doped fiber amplifier

Optical fiber communication is of great importance in information transmission. Increasing the transmission capacity of optical fiber systems is a solution to meet the increasing demand for information, in which rare earth ion-doped fiber amplifiers play an important role. In this paper, the quasi-quadruple-energy structure of is equated and simplified to a conventional triple-energy structure to improve amplification's efficiency and significance. By exploring the influence of many factors on the praseodymium-doped fiber amplifier, the amplification band with gain window between 1250-1350nm is verified, and the amplification of the central wavelength of 1310nm is realized. It provides a theoretical reference for the subsequent application of praseodymium-doped fiber amplifiers in communication engineering, laser amplification and other fields. Since the amplification band of praseodymium-doped fiber amplifier matches the zero dispersion point of 6.652 optical fiber, it will have a huge application market in the 1310nm optical communication system.

Design and Analysis of an O+E-Band Hybrid Optical Amplifier for CWDM Systems.

Broadband amplification in the O+E-band is very desirable nowadays as a way of coping with increasing bandwidth demands. The main issue with doped fiber amplifiers working in this band such as the bismuth-doped fiber amplifier is that they are costly and not widely available. Therefore, a wideband and flat-gain hybrid optical amplifier (HOA) covering the O+E-band based on a parallel combination of a praseodymium-doped fiber amplifier (PDFA) and a semiconductor optical amplifier (SOA) is proposed and demonstrated through numerical simulations. The praseodymium-doped fiber (PDF) core is pumped using a laser diode with a power of 500 mW that is centered at a wavelength of 1030 nm. The SOA is driven by an injection current of 60 mA. The performance of the HOA is analyzed by the optimization of various parameters such as the PDF length, Pr3+ concentration, pump wavelength, and injection current. A flat average gain of 24 dB with a flatness of 1 dB and an output power of 9.6 dBm is observed over a wavelength range of 1270-1450 nm. The noise figure (NF) varies from a minimum of 4 dB to a maximum of 5.9 dB for a signal power of 0 dBm. A gain reduction of around 4 dB is observed for an O-band signal at a wavelength of 1290 nm by considering the up-conversion effect. The transmission performance of the designed HOA as a pre-amplifier is evaluated based on the bit-error rate (BER) analysis for a coarse wavelength-division multiplexing (CWDM) system of eight on-off keying (OOK)-modulated channels, each having a data rate of 10 Gbps. An error-free transmission over 60 km of standard single-mode fiber (SMF) is achieved for different data rates of 5 Gbps, 7.5 Gbps, and 10 Gbps.

Performance evaluation of O-band praseodymium-doped fiber amplifier with dual-pass regime

ABSTRACT In this work, compact praseodymium-doped fiber amplifiers (PDFAs) with single- and dual-pass configurations are designed and investigated in the O-band region based on theoretical simulation. The impact of doped fiber characteristics, input signal power and input pumping power on the gain and the noise figure of the proposed amplifiers are comprehensively considered and compared. At an input pumping power of 350 mW and optimum praseodymium-doped fiber (PDF) length, the obtained results show that dual-pass model recorded higher gain than the single-pass scheme. This occurs because of the dual propagation of the forwarded and amplified spontaneous emission (ASE) signal through the gain medium. Moreover, both proposed configurations exposed better amplification performance at an input signal power of −10 dB compared to the higher input signal power of 0 dB. The dual-pass regime shows higher amplification gain than the single-pass one of about 4 dB and a maximum power conversion efficiency (PCE) of 14%. Indeed, the PDF core radius and doping concentration are considered as vital factors. Decrement of doped-core radius leads to a notable gain increment and NF decay, whereas low doping concentrations show very small signal gain compared to the optimized value.

PAM4 based symmetrical 112-Gbps long-reach TWDM-PON

We experimentally demonstrate cost effective symmetrical 112-Gbps long-reach passive optical network (LR-PON) over 70-km standard signal mode fiber (SSMF), based on pulse amplitude modulation (PAM)-4. Four 10G-class directly modulated lasers (DMLs) at C-band are used for achieving 4×28-Gbps downstream transmission, while two 18G-class DMLs at O-band are used to realize 2×56-Gbps upstream transmission, without any optical amplification in optical distributed network (ODN). Both dispersion compensation fiber (DCF) for downstream signal and praseodymium-doped fiber amplifier (PDFA) for upstream signal are equipped at optical line terminal (OLT). Meanwhile, sparse Volterra filter (SVF) equalizer is proposed to mitigate the transmission impairments with substantial reduction of computation complexity. Finally, we can successfully provide a loss budget of 33 dB per downstream wavelength channel, indicating of 64 optical network units (ONUs) with more than 1.25 Gbps per ONU.

Experimental performance of semiconductor optical amplifiers and praseodymium-doped fiber amplifiers in 1310-nm dense wavelength division multiplexing system

One of the key optical transmission components is optical amplifiers. Studies on the amplification properties of the 1310-nm optical amplifiers are presented. The evaluated optical amplifiers are semiconductor optical amplifier (SOA) and praseodymium-doped fiber amplifier (PDFA). The study is aimed at the dynamic operation in single- and multiwavelength domains with high rate signals. The maximum obtained gain was 25.0 dB for SOA and 20.9 dB for PDFA. For the SOAs, the minimum achieved value of the receiver sensitivity was −11.5 dBm for a single channel and −11.5 dBm for a dense wavelength division multiplexing case while for PDFA those values were −11.0 dBm and −10.9, respectively. The main advantage of the PDFA in comparison to the measured SOAs is its higher saturation power. The SOAs proved to be viable candidates for high-speed amplification in the 1310-nm wavelength domain.

2 × 64 Gb/s PAM-4 transmission over 70 km SSMF using O-band 18G-class directly modulated lasers (DMLs).

We experimentally demonstrate 2 × 64 Gb/s PAM-4 transmission over a 70 km standard single-mode fiber (SSMF) using two O-band 18G-class directly modulated lasers (DMLs). Only one praseodymium-doped fiber amplifier (PDFA) at the receiver side is used to compensate the transmission loss. Meanwhile, transmission impairments are compensated by a sparse Volterra filter (SVF) equalizer, which can achieve similar system performance but with half the computational complexity (CC), in comparison with a traditional VF equalizer. Finally, we optimize the insignificant factor (IF) of SVF to identify the trade-off between the transmission performance and the CC. Thus, the redundancy of individual SVF kernels can be reasonably removed.

ALC Burst-Mode Optical Fiber Amplifiers for 10 Gb/s-Class Long-Reach PONs

This paper proposes a burst-mode optical fiber amplifier (OFA) that consists of a combination of an automatic gain controlled praseodymium-doped fiber amplifier (AGC-PDFA), a fast automatic level controlled circuit (ALC), and a PDFA with just forward pumping. The second PDFA is used as a booster to achieve high gain, over 20 dB. The combination of AGC and ALC techniques suppresses optical surge generation against strong burst signal inputs and also prevents overloading of the burst-mode receivers; it provides OFA-based passive optical network (PON) repeaters with wide input dynamic range and solves the near–far problem in upstream transmission in long-reach PONs. We experimentally compare the operating range of the proposed burst-mode PDFA with that of a conventional burst-mode PDFA. Experiments show that the proposed PDFA achieves a much wider operating area than a conventional PDFA; a wide dynamic range in an access span of 17.5 dB, which is equivalent to the input dynamic range of the burst-mode receiver used in 10 gigabit Ethernet PON (10G-EPON), is obtained with an allowable loss margin of 14 dB in a trunk span. A maximum link budget of 55 dB is achievable.

Noise figure and gain temperature dependent of praseodymium-doped fiber amplifier by using rate equations

A theoretical study of the temperature dependent noise effects of praseodymium-doped fiber amplifiers (PEDFAs) has been examined. The Pr 3+-doped ZBLAN fiber amplifier pumped at 1017 nm and Pr 3+-doped GeGa-sulfied fiber amplifier pumped at 1028 nm are chosen. The temperature-dependent rate and propagation equation related to four-level system consideration which is based on the population difference among amplification levels has been used. The population difference depends on pump and signal powers, Boltzman factor K B , cross-sections, noise figure (NF) and Pr 3+ concentration. The numerical results obtained over the temperature range from −20 °C to + 60 °C are used to present an analytical expression for the signal gain and noise figure effects in PDFAs length and noise figure with input pump power. The amplified spontaneous emission (ASE) has been taken into account.

Modelling consideration of praseodymium-doped fiber amplifiers for 1.3 μm wavelength applications

To obtain the temperature-sensitive rate equations, a new energy level diagram of Praseodymium ion (Pr3+) in a glass host is modelled. By solving the modified rate equations, an analytical expression is presented to investigate the temperature dependence of the signal gain of a praseodymium-doped fiber amplifier (PDFA). It is seen that a change in the signal gain slightly depends on the variation of the distribution of Pr3+-ions in transitions 3F4↔3F3 with the temperature. Numerical calculations are carried out for the temperature range which is changing from −20 to +60°C. Pr3+-doped ZBLAN fiber amplifier pumped at 1017nm and Pr3+-doped sulfide fiber amplifier pumped at 1028nm are selected as an application for the 1.3μm signal wavelengths. It is also seen that the prediction of the model is in good agrement with their experimental results.

Hybrid wavelength-division-multiplexing transport systems based on praseodymium-doped fiber amplifiers

A hybrid wavelength-division-multiplexing transport system based on 1.3-µm optical transmitters and praseodymium-doped fiber amplifiers is proposed and demonstrated. It uses one wavelength for AM vestigial-sideband CATV, one wavelength for 256-QAM digital passband, and one wavelength for OC-48 digital baseband signals. Good performance with respect to composite second order and composite triple beat has been obtained at an acceptable carrier-to-noise ratio for CATV; and a low bit error rate has been achieved for 256-QAM and OC-48 digital signals over a 70-km single-mode fiber transport.

High-power and highly reliable 1020-nm ridge waveguide laser diodes with small aspect ratio as a pumping source for praseodymium-doped fiber amplifiers

The structure of an asymmetrically expanded optical field normal to the active layer was applied to 1020-nm ridge waveguide laser diodes in order to increase their maximum kink-free output power and reduce the aspect ratio of the output beams. As a result, a kink-free output power of more than 400 mW and an aspect ratio of less than 2.5 were achieved by this structure. Good reliability was also obtained at an output power of 300 mW at 50/spl deg/C.

Forward Pumping PDFA Modelling and Application on the CATV Systems

In this paper, we first deduce a model of Praseodymium-doped fiber amplifiers using the transitions between different energy states and the rate equations. Base on this model, the characteristics of Praseodymium-doped fiber amplifiers are investigated numerically. An experimental Praseodymium-doped fiber amplifier operating around 1300 nm is implemented to verify the model. The measurements of this amplifier, which has small signal gain of 16 dB, bandwidth of 27 nm, and amplified spontaneous emission noise less than -33 dBm, agree with the model quite well. Because many cable television systems are operating around this wavelength, we apply a Praseodymium-doped fiber amplifier to a cable television system with both analog and digital signals. The experimental results show that the changes of the carrier-to-noise ratio, composite-second-order distortion, composite-triple-beat distortion and bit error rate of the system with and without the amplifier are insignificant.

Hybrid AM-VSB/256-QAM WDM system over 70 km of single-mode fiber with praseodymium-doped fiber amplifier

A directly modulated 1.3-mm 77-channel AM-VSB video and 63-channel simulated 256-QAM digital signals lightwave long-haul transmission system using a praseodymium-doped fiber amplifier (PDFA) and split-band and wavelength-division multiplexing (WDM) techniques is demonstrated. A high system performance of carrier-to-noise ratio (CNR) .50 dB, composite second order (CSO) .65.5 dB, and composite triple beat (CTB) .64 dB for AM-VSB is obtained, accompanied with carrier-to-noise and nonlinear distortion ratio (C/(N1NLD)).38 dB for 256-QAM. © 2002

Development of germanium gallium sulphide glass fibres for the [formula omitted] praseodymium-doped fibre amplifier

We report on our current progress in the development of germanium gallium sulphide glass fibres for the praseodymium-doped fibre amplifier (PDFA). Praseodymium-doped glasses with compositions (GeS x ) 98(GaS 3) 2 ( x: 2.25, 2.5, 3) are melted from germanium and gallium metals and sulphur in sealed silica ampoules at 1000°C and then quenched in air. The critical step in the fibre manufacturing process is the fabrication of the fibre preform out of glass rods. The `rod in tube' method was selected for preform fabrication. A new hot deformation process for manufacturing cladding tubes using the visco-elastic properties of the glass is described. A measure for the thermal stability of the glasses is the difference between the glass transition temperature, T g, and the crystallisation onset temperature, T x. The thermal stability was evaluated using dilatometry and combined differential thermal analysis/thermogravimetry (DTA/TG) analysis for determining T g and T x. For the selected germanium gallium sulphide glasses the difference between the crystallisation temperature and glass transition temperature is more than 200°C. Both the fibre drawing temperature and the hot deformation temperature (to produce cladding glass tubes) are less than the crystallisation onset temperature. The germanium gallium sulphide host glasses are transparent in the 0.5–10 μm wavelength region. The wavelength of the maximum of the stimulated emission band with full width at half maximum (FWHM) amplitude of 80 nm is 1.34 μm , the emission lifetime is 390 μs .

A 980-nm band laser diode pump source with a detuned wavelength of 1000 nm for praseodymium-doped fiber amplifiers

By using practical high-power 980-nm band laser diodes, efficient direct pumping for a praseodymium-doped fiber amplifier (PDFA) is achieved. The lasing wavelength is detuned from 980 to 1000 nm by selective optical feedback from a fiber grating.

Development of an efficient praseodymium-doped fiber amplifier

This paper describes the development of an efficient praseodymium-doped fluoride fiber amplifier (PDFA) using newly developed PbF/sub 2/-InF/sub 3/-based fluoride single-mode fiber. First, the spectroscopic properties of Pr/sup 3+/ in PbF/sub 2/-InF/sub 3/-based and ZrF/sub 4/-based fluoride glass are compared and then the fabrication of high-NA PbF/sub 2/-InF/sub 3/-based fluoride single-mode fiber is presented. The gain coefficients obtained with the developed fiber are 0.36 dB/mW with a forward pumping scheme and 0.4 dB/mW with a bidirectional pumping scheme. We use this newly developed fiber to construct two types of an efficient PDFA module. We realized a 19-in rack size PDFA module with a master oscillator/power amplifier laser diode (MOPA-LD) and a plug-in type PDFA module with a wavelength-stabilized 1.017-/spl mu/m LD and describe their amplification characteristics.

High output-power praseodymium-doped fiber amplifier single-pumped at 1030 nm: analysis and results

We present theoretical and experimental characterization of a high-gain and high-output power Pr/sup 3+/-doped fluoride-fiber amplifier. A comprehensive theoretical analysis of the amplifier has been carried out for the case of large signals. Thorough experimental characterization of the amplifier is reported, and +20-dBm output power has been obtained.

Analysis of gain characteristics of bi-directionally pumped praseodymium-doped fiber amplifiers

Signal gain and noise figure in a bi-directional pumping configuration are investigated in the unsaturated and saturated region. Balanced and asymmetric bi-directional pumping configurations are effective in the unsaturated and saturated region, respectively. Especially, an asymmetric bi-directional pumping configuration with larger backward pump power than forward pump power increases the pump to signal conversion efficiency in the saturated region. An asymmetric pumping configuration is effective in constructing booster amplifiers.

Praseodymium doped fibre amplifiers (PDFAs) pumped by monolithic master oscillator power amplifier (M-MOPA) laser diodes

Praseodymium-doped ZBLAN fibre amplifiers pumped by high power M-MOPA laser diodes demonstrate output powers up to 17.1 dBm and small signal gain levels up to 26 dB at 1.31 µm wavelength. Optical receiver preamplification using an M-MOPA pumped PDFA results in a 4 dB sensitivity improvement for a 2.5 Gbit/s transmission experiment.