Er-Yb Co-doped Fiber Amplifier Research Articles

High-power, sub-100-fs, 1600-1700-nm all-fiber laser for deep multiphoton microscopy.

The 1600-1700-nm ultrafast fiber lasers attract great interests in the deep multiphoton microscopy, due to the reduced levels of the tissue scattering and absorption. Here, we report on the 86.7-MHz, 717-mW, 91.2-fs, all-fiber laser located in the spectral range from 1600 nm to 1700nm. The soliton self-frequency shift (SSFS) was introduced into the Er:Yb co-doped fiber amplifier (EYDFA) to generate the high-power, 1600-1700-nm Raman soliton. Detailed investigations of the nonlinear fiber amplification process were implemented in optimizing the generated Raman soliton pulses. The miniature multiphoton microscopy was further realized with this home-built laser source. The clearly imaging results can be achieved by collecting the generated harmonic signals from the mouse tail skin tissue with a penetration depth of ∼500 µm. The experimental results indicate the great potential in utilizing this 1600-1700-nm fiber laser in the deep multiphoton microscopy.

Achieving gain flattening over 110 nm bandwidth using Er-Yb co-doped fiber/multi-section fiber optical parametric hybrid amplifier

This work demonstrates optical amplification in the entire C- and L-bands. A hybrid amplifier consisting of one stage of Er-Yb co-doped fiber amplifier (EYDFA) and two stages of fiber optical parametric amplifier is proposed. The EYDFA and parametric amplifier parameters have been carefully selected to achieve gain over complementary bandwidth regions, resulting in better gain flatness over 110 nm bandwidth. The proposed amplifier is investigated for 12 × 100 Gb/s wavelength division multiplexed system at channel spacing of 10 nm. Results show a flat gain of >27.42 dB with gain ripple of 3.17 dB, obtained over a wavelength range of 1530 to 1640 nm.

Power scalability of a continuous-wave high-power Er-Yb co-doped fiber amplifier pumped by Yb-doped fiber lasers.

The power scaling of Er-Yb co-doped fiber lasers and amplifiers has been limited by the bottleneck effect of energy-transfer saturation between Yb ions and Er ions. The emerging method of Er-Yb co-doped fiber amplifiers pumped by Yb-doped fiber lasers is considered as an approach to enhance the threshold of the bottleneck effect. In this paper, we quantitatively characterize the threshold of the bottleneck effect via the method of extreme value analysis of the second-order derivative. The method facilitates the optimization of the amplifier configuration. Afterward, we numerically investigate the bottleneck effect of various Er-Yb co-doped fiber amplifiers off-peak cladding-pumped by 10××nm Yb-doped fiber lasers for what we believe, to the best of our knowledge, is the first time. The result shows that the most optimal configuration is long gain fiber over 20 m pumped by a 1020-1025 nm fiber laser, with more than two times the output limit of a conventional laser diode pumping scheme. The essential factors of an amplifier are discussed afterward, including the pump-launching direction, the optimization of large-mode-area fiber, the core-cladding ratio, the concentration of doping ions, the nonlinearity limit, and the distribution of the heat load.

High-speed fiber system capacity with bidirectional Er-Yb CDFs based on differential phase shift keying (DPSK) modulation technique

Abstract This paper simulates the bidirectional Er-Yb codoped fiber amplifiers (CDFs)-based DPSK modulation scheme for high speed fiber system capacity. The combination of Erbium-Ytterbium codoped fibers into a single fiber has been developed for the extension of the absorption bands for doped fibers. The signal gain variations versus pump wavelength variations have been demonstrated for various doped amplifiers with the proposed Er-Yb CDFs at amplifier length of 5 m. Also the signal gain variations versus pump wavelength variations have been illustrated for the proposed Er-Yb CDFs at 5 m amplifier length in different pumping configurations. The total optical power, max. Q factor, total electrical power, output optical signal/noise ratio, and signal gain variations versus fiber length variations have between simulated and clarified in the presence of bidirectional various lengths of Er-Yb CDFs.

18 W single-frequency 1550 nm Er:Yb co-doped fiber amplifier cladding-pumping at 1018 nm

A continuous wave (CW) 1550 nm single-frequency fiber amplifier based on a double-clad Er:Yb co-doped fiber, featuring off-peak cladding-pumping at 1018 nm, is demonstrated for the first time to our knowledge. Compared with the traditional single-mode Er:Yb co-doped fiber amplifiers (EYDFA) pumping at 9xx nm, for which the threshold of Yb-band amplified spontaneous emission (ASE) at 1.0μm region was several watts level, the Yb-band ASE threshold was enhanced to 17.0 watts. Experimentally, a homemade 1018 nm fiber laser was used as the pump source, which can provide an average power of ∼76 W. The 1550 nm signal power of 18.0 W was achieved, when the pump power was 71 W. This result indicates that off-peak pumping at 1018 nm is a promising scheme for achieving high-power single-frequency EYDFA at 1.5μm region.

Performance evaluation of hybrid optical amplifiers for a 100 × 10 Gbps DWDM system with ultrasmall channel spacing

In this paper, various hybrid optical amplifier configurations have been proposed and investigated for a 100 × 10 Gbps dense wavelength division multiplexed system at 0.2 nm channel spacing. The performance is evaluated and compared in terms of gain, noise figure (NF) and Q-factor in the C-band over the wavelength range of 1540–1560 nm. The proposed combinations of optical amplifiers are Er-Yb co-doped waveguide/Raman amplifier, Er-Yb co-doped fiber amplifier (EYDFA)/Raman, Raman/EYDFA and EYDFA/fiber optical parametric amplifier (FOPA). It is observed that high gain with better gain flatness and low NF are obtained for both EYDFA–FOPA and EYDFA–Raman hybrid amplifiers. Overall lowest gain ripple is obtained for the EYDFA–Raman configuration. At the transmission distance of 50 km, a good Q-factor (>9.5 dB) is obtained at each wavelength for all the amplifiers, with EYDFA–Raman having slightly higher values.

Gain flattened C-band hybrid optical amplifier achieving high and flat gain over 32-nm bandwidth for dense wavelength division multiplexed system

Increase in data rate demand requires continuous improvement in existing optical amplification schemes. This work demonstrates optical amplification, simulating a hybrid combination of Er-Yb codoped fiber amplifier (EYDFA) and dual pump fiber optical parametric amplifier (FOPA). The proposed EYDFA–FOPA hybrid amplifier is investigated over a wavelength range of 1533–1565 nm for 160 × 10 Gbs − 1 dense wavelength division multiplexed (DWDM) system at 0.2-nm channel spacing. The parameters are optimized to achieve a flat gain of >28.4 dB, with a gain ripple of 2.09 dB at −20 dBm optimum input power per channel. Also, analysis at different input power shows that for higher input powers up to −5 dBm, an increase in gain ripple up to 5.07 dB is observed. Further, a comparison with EYDFA–single pump FOPA configuration shows that much better gain flatness is obtained for the proposed hybrid amplifier. The obtained high and flat gain, along with the low noise figure, justifies the feasibility of the proposed amplifier for applications in broadband long-haul DWDM systems.

Numerical achievement of high and flat gain using Er-Yb co-doped fiber/Raman hybrid optical amplifier

A novel hybrid optical amplifier is proposed for 100 × 10 Gb/s dense wavelength division multiplexed (DWDM) system. The amplifier consists of a combination of Er-Yb co-doped fiber amplifier (EYDFA) with backward-propagating multi-pump Raman amplifier. A flat gain of >26 dB is achieved, over a wavelength range of 1545–1565 nm. The scheme works at 1 mW optimum input power per channel. Gain ripple of 1.37 dB and noise figure (NF) of <4.5 dB is observed. Anyhow, for higher input powers up to 10 mW, an increase in gain ripple up to 7.59 dB and NF up to 12.04 dB is observed. The effects of varying various parameters, like EYDFA pump wavelength, EYDFA length, Er/Yb concentrations and Raman length are also investigated. The obtained high and flat gain, along with the low NF, lesser bit error rate and high Q-factor, justifies the usefulness of proposed amplifier for applications in long-haul DWDM systems.

Novel flat-gain L-band Raman/Er-Yb co-doped fiber hybrid optical amplifier for high capacity DWDM system

A novel flat-gain L-band hybrid optical amplifier is demonstrated using a combination of Raman and Er-Yb co-doped fiber amplifier (EYDFA) for a high capacity 80 × 100 Gb/s dense wavelength division multiplexed (DWDM) system at 0.2 nm channel spacing. The parameters of the proposed Raman–EYDFA hybrid amplifier are optimized using numerical techniques based on genetic algorithms to achieve a flat gain of >22 dB, with a gain ripple of 0.89 dB. This is obtained over a wavelength range of 1571–1587 nm at 1 mW optimum input power per channel, without using any costly gain clamping technique. The obtained noise figure (NF) is less than 6 dB for the given wavelength range. The overall decrease in gain and increase in NF is observed with the increase in input power. The obtained high and flat gain, along with the low NF and good Q-factor and bit error rate, confirms the feasibility of proposed amplifier for applications in broad band long-haul DWDM systems.

Numerical investigation of the thermal effect on Yb-cavity-copumped Er/Yb codoped fiber amplifiers.

Thermal effects are critical constraints for developing high-power Er/Yb-codoped fiber amplifiers (EYDFAs), especially those with an auxiliary Yb-band cavity. In this paper, we developed a numerical model to investigate the temperature-dependent effects on EYDFAs with an Yb-band cavity with consideration of thermal-induced cross-section changes. Our results show that the quantum-defect-induced heat affects the performance of the EYDFA, and its effect varies with the resonant wavelength of the Yb-band cavity. There is a finite applicable resonant wavelength range limited by thermal damage. So, it is important to take into account the thermal effect during the design of such EYDFAs in order to optimize their performance and determine the heat dissipation systems.

Single-frequency fiber amplifier at 1.5 µm with 100 W in the linearly-polarized TEM00 mode for next-generation gravitational wave detectors.

Next-generation gravitational wave detectors require single-frequency and high power lasers at a wavelength of 1.5 µm addressing a set of demanding requirements such as linearly-polarized TEM00 radiation with low noise to run for long periods. In this context, fiber amplifiers in MOPA configuration are promising candidates to fulfill these requirements. We present a single-frequency monolithic Er:Yb co-doped fiber amplifier (EYDFA) at 1.5 µm with a linearly-polarized TEM00 output power of 100 W. The EYDFA is pumped off-resonant at 940 nm to enhance the Yb-to-Er energy transfer efficiency and enable higher ASE threshold. We also performed numerical simulations to investigate the off-resonant pumping scheme and confirm the corresponding experimental results.

Highly efficient Er–Yb codoped double-clad fiber amplifier with an Yb-band resonant cavity

A high-power Er–Yb codoped fiber amplifier (EYDFA) with an Yb-band resonant cavity is investigated. By introducing a linear resonant cavity formed by a pair of high-reflection double-clad fiber Bragg gratings, the Yb-ASE problem of high-power pumped EYDFAs can be resolved and the efficiency of the amplifier can be notably improved. At a pump power of ~17 W, an output power of 7.25 W was experimentally achieved. The pump conversion efficiency and slope efficiency relative to the applied pump power are ~42.6% and ~45.6%, respectively. Moreover, due to the gain-clamping effect of the Yb cavity, the gain flatness of the amplifier is also evidently improved.

Ultra-flat supercontinuum generated from high-power, picosecond telecommunication fiber laser source.

An ultra-flat, high-power supercontinuum generated from a picosecond telecommunication fiber laser was presented. The pulse from a carbon nanotube mode-locked oscillator was amplified using an Er-Yb codoped fiber amplifier. The output of the system achieved an average power of 2.7W, with the center wavelength at 1564nm and a FWHM of 6nm in the spectral domain. By passing this amplified high-power pulse through a 4.6m highly nonlinear photonic crystal fiber, an ultra-flat supercontinuum spanning 1600-2180nm is generated. And the average power of the supercontinuum achieves 1W.

Study characteristics of 27 dBm Er/Yb co-doped/Raman hybrid amplifier (HA) compared to Er/Yb Co-doped fiber amplifier only

We present the gain and noise figure characteristics of Er-Yb co-doped/Raman hybrid amplifier (HA) compared to Er-Yb co-doped fiber Amplifier (EYDFA) only to improving the characteristics performance of optical amplifier. The work is done, at pump power of 27dBm≈500mW for both amplifiers (in the case of HA, 300mW for Er-Yb co-doped and 200mW for Raman amplifier (RA)). The gain and noise figure measured at (0.7 and 1m) lengths of Er-Yb co-doped, 25km Raman amplifier length and input signal power of (−40 to 10dBm) in the signal wavelength range (1525–1610nm). A large gain 40.33dB is obtained for the hybrid amplifier compared to Er-Yb co-doped amplifier only by increasing 7.33dB at 1530nm and −30dBm and a flat gain is observed in the all range of signal wavelength. Furthermore at lower input signal power −40dBm, the new hybrid amplifier, offer gain increasing to ∼13dB rather than its value at −30dBm signal power and 15dB in compared with Er-Yb co-doped amplifier only.

Optimal design of Er/Yb co-doped fiber amplifiers with an Yb-band fiber Bragg grating

In this paper, Er/Yb co-doped fiber amplifiers (EYDFAs) with an Yb-band fiber Bragg grating (FBG) at the pump end to improve the performance of the amplifier is systematically studied. The influence of the reflectivity and center wavelength of the FBG along with the gain-fiber length on the performance of an EYDFA are numerically analyzed. The results show that the wavelength of the FBG has critical influence on the efficiency of the EYDFA, whereas the requirement to its reflectivity is relaxed. It is an effective and promising way to improve the efficiency of a high-power pumped EYDFA by introducing a suitable Yb-band FBG at the pump end. Based on the analysis of the underlying principles, suggestions for the practical design and possible further improvement strategies are also proposed.

Gain and noise figure enhancement of Er+3/Yb+3 co-doped fiber/Raman hybrid amplifier

An Er/Yb co-doped fiber/Raman hybrid amplifier (HA) is proposed and studied theoretically and analytically to improve the gain and noise figure of optical amplifiers. The calculations are performed under a uniform dopant and steady-state conditions. The initial energy transfer efficiency for Er/Yb co-doped fiber amplifier (EYDFA) is introduced, while the amplified spontaneous emission (ASE) is neglected. The glass fiber used for both Er/Yb and Raman amplifiers is phosphate. Different pump powers are used for both EYDFA and RA with 1μW input signal power, 1m length of Er/Yb amplifier and 25km length of Raman amplifier (RA). The proposed model is validated for Er/Yb co-doped amplifier and Raman amplifier separately by comparing the calculating results with the experimental data. A high gain and low noise figure at 200mW Raman pump power and 500mW Er/Yb pump power are obtained for the proposed HA as compared with the experimental results of EYDFA, Raman amplifier and the EDFA/Raman hybrid amplifier.

Highly efficient Er/Yb-codoped fiber amplifier with an Yb-band fiber Bragg grating.

In this Letter, a high-power Er/Yb-codoped fiber amplifier (EYDFA) with a high-reflection Yb-band fiber Bragg grating (FBG) at the pump end is experimentally investigated. The FBG was inscribed on a piece of double-clad fiber with a center wavelength of 1032 nm. Due to the selective reflection of the backward Yb-band amplified spontaneous emission (Yb ASE) by the FBG, a co-pump-propagating Yb-band auxiliary signal was generated. Because of the stimulated amplification and reabsorption of the auxiliary signal, the Yb ASE was dramatically suppressed and the pump conversion efficiency (PCE) of the EYDFA was notably improved. An output power of 6.48 W was achieved at a pump power of 16.5 W, which is equivalent to a PCE of ∼39%. The slope efficiency relative to applied pump power was ∼40%. The maximum output power was improved ∼20% because of the introduction of the FBG.

Wavelength tunable single longitudinal mode fiber laser pinned to 25 GHz spacing

ABSTRACTA wavelength tunable single longitudinal mode (SLM) fiber laser is demonstrated with a high power Er‐Yb codoped fiber amplifier (EDFA) used as gain medium. A fiber Fabry‐Perot filter and a bandpass filter ensure single wavelength lasing. To realize SLM operation, a section of unpumped EDF in a Sagnac loop is adopted as a saturable absorber, which results in a self‐induced FBG (frequency band gap) with an ultranarrow bandwidth. The proposed laser is very stable and in SLM operation. The signal to noise ratio is measured about 65 dB. The output laser has a tuning range over 30 nm from 1535 to1565 nm. The tuning step of the proposed laser is 0.20 nm pinned to the ITU grid. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2404–2406, 2014

高功率脉冲抽运Er-Yb共掺光纤放大器的理论研究

高功率脉冲抽运Er-Yb共掺光纤放大器的理论研究

Several hundred kHz repetition rate nanosecond pulses amplification in Er–Yb co-doped fiber amplifier

We have experimentally investigated several hundred kHz repetition rate 1,550-nm nanosecond pulses amplification in Er–Yb co-doped fiber amplifier (EYDFA). The experimental setup has three stage fiber amplifiers. At the output of the second stage EYDFA, Yb3+ ions induced amplified spontaneous emission (Yb-ASE) is not observed owing to the low pump power. In the third stage EYDFA, a simultaneously seeded 1,064-nm continuous-wave laser is used to control Yb-ASE. Without any additional 1,064-nm signal, significantly backward Yb-ASE which caused loss-induced heat accumulation at the input port of the pump combiner can be observed. The monitored temperature at the input port of the pump combiner rapidly grows from 30 to 80 °C when the pump power is turned from 20 to 32 W. When a 196-mW forward 1,064-nm laser is added, the monitored backward Yb-ASE power is significantly declined, and the monitored temperature is kept below 35 °C. But, the additional signal caused a large power fraction at 1,064 nm in the output laser. In our experiment at the maximum pump power of 48.5 W, the total output power is 20 W with ~6.4-W 1,550-nm pulsed laser and ~13-W 1,064-nm continuous-wave laser.