Erbium-doped Superfluorescent Fiber Source Research Articles

Improvement of the Temperature Stability of the Erbium-Doped Superfluorescent Fiber Source by Tuning the Reflectivity of the Fiber End

A novel and simple way of improving the mean wavelength temperature stability of the erbium-doped superfluorescent source is described and demonstrated. We show that by introducing small reflectivity feedback at the unpumped fiber end in the backward-pump superfluorescent source configuration, we can affect an overall temperature dependency of the mean wavelength of the output spectrum. The reflectivity adjustment can be made by an angled fiber cleave, varying the reflectivity between 0 to 4 %, or by a fusion arc, allowing its finer adjustment. With this approach, we were able to arbitrarily adjust the mean wavelength temperature trend from −4.38 to 5.23 ppm/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> C. Furthermore, an optimal reflectivity was attained, providing almost zero trend and reducing the total mean wavelength variation to 130 ppm over the temperature range of −40 to +100 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> C, which is a 5.7-fold and 4.4-fold improvement compared to 0 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> and a standard 8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> fiber cleave angle, respectively. By avoiding any filtering components, a wide bandwidth of 37.8 nm and a power efficiency of 22% was reached. Since the proposed configuration does not include any extra components compared to the basic backward-pump configuration, it can be a viable solution for cost-efficient applications, such as, e.g., medium-grade fiber-optic gyroscopes. A benefit for these gyroscopes is the tunability of the source wavelength temperature dependency which can conveniently compensate the gyro coil temperature sensitivity.

Influence of temperature on detectable minimum rotation rate in i-FOGs using Er-doped SFSs

Abstract In this study, an interferometric fiber optic gyroscope (I-FOG) model exploiting the double-pass backward (DPB) erbium-doped superfluorescent fiber source (SFS) with both thin-film filter (TFF) and fiber bragg grating (FBG) reflectors has been constructed and the effects of temperature variations on mean wavelength and detectable minimum rotation rate (DMRR) have been theoretically analyzed. the simulations corresponding with the relations between these parameters for temperature variations in the range of −60 °C to + 90 °C, have been performed using Matlab 2021b. DMRR variations have been found as 6.01 ppm/K and 3.83 ppm/K for the system with TFF, whilst they are 15.31 ppm/K and 1.58 ppm/K for the system with FBG.

Gamma radiation effects on erbium-doped fiber in superfluorescent fiber source

The radiation effects of two erbium-doped superfluorescent fiber sources (SFSs) are studied in gamma ray environment. Two types of output spectrum profile (twin-peaked spectrum and single-peaked spectrum) of SFSs are constructed by different configuration and parameters. The dependence of radiation-induced power loss and spectra evolution on the dosage is revealed. The results show that the amplitudes of radiation-induced power decrease are quite similar in two SFSs. But the mean wavelength variation of the single-peaked spectrum SFS is approximately 25times smaller than that of the twin-peaked spectrum SFS. Compared to the twin-peaked spectrum SFS, the single-peaked spectrum SFS presents better radiation tolerance, which should have potential advantages in space applications.

High-stable and broadband erbium-doped superfluorescent photonic crystal fiber source

A high-stable and broadband single-pass backward configuration superfluorescent fiber source based on erbium-doped photonic crystal fiber (EDPCF) is proposed. With the proper EDPCF length, pump power, and a gain flattening filter, we demonstrate that it is possible to create a high-stable and broadband erbium-doped superfluorescent photonic crystal fiber source (SPCFS). This was accomplished by replacing the conventional erbium-doped fiber with the EDPCF, the intrinsic thermal coefficient of which is four times less than the measured conventional erbium-doped fibers. The SPCFS showed that the total output power stability was less than 0.0337%, the 3-dB spectral width was broader than 42 nm, the output spectrum flatness was less than 1 dB, and the mean wavelength stability was less than 2.58 ppm over 6 h at temperatures from 24.3°C to 25.5°C, which approached the requirement for inertial-grade fiber optic gyroscopes.

高功率高效率掺铒光纤超荧光光源

高功率高效率掺铒光纤超荧光光源

Experimental optimization of an erbium-doped super-fluorescent fiber source for fiber optic gyroscopes

Double-pass forward and double-pass backward erbium-doped super-fluorescent fiber sources (ED-SFSs) were combined in one configuration. A 980 nm laser diode pumped the same erbium-doped fiber from both directions using a coupler as a power splitter. The double-pass configuration was achieved by coating the fiber end face. Firstly, an optimal fiber length was found to obtain a high stability of output light wavelength with pump power, and then 1530/1550 nm wavelength division multiplexing was used for spectrum planarization, which expanded the bandwidth to more than 22 nm. The final step was a test of temperature stability. The results show that the rate of the central wavelength change kept to below 3.5 ppm/°C in the range of −40 to 60 °C and 1–2 ppm/°C in the range of 20–30 °C. Considering all the three factors of the fiber optic gyro applications, we selected 80 mA as the pump current, in which case the central wavelength temperature instability was calculated as 2.70 ppm/°C, 3 dB bandwidth 22.85 nm, spectral flatness 0.2 dB, output power 5.17 mW and power efficiency up to 9.92%. This experimental result has a significant reference value to the selection of devices and proper design of ED-SFSs for the application of high-precision fiber optic gyroscopes.

双后向结构的线宽拓展L波段超荧光光源

A linewidth broadening and high efficiency erbium-doped superfluorescent fiber source(SFS) by using the cascaded dual-backward pumped configuration is proposed.The effects of fiber length arrangement and pump power ratio on the output characteristics of the L-band SFS are investigated by simulation.The simulational results show that the linewidth broadening L-band SFS can be achieved by the proposed design.The spectral linewidth is over 15 nm broader compared with the conventional L-band SFS,up to 60 nm.Further more,the design gives the highest pump efficiency at pump power ratio of 0.5.An L-band SFS of 62 mW output power,30.1% pump efficiency and 56.6 nm linewidth is experimentally achieved with 206 mW pump power of a 980 nm LD.

Ultra-high-efficiency L-band erbium-doped superfluorescent fiber source with broadening linewidth

We investigate a high-pumping-efficiency and linewidth-broadening, L-band, erbium-doped, superfluorescent fiber source (SFS) using a cascaded dual-backward-pumped configuration. With optimized structural parameters, the design provides an L-band SFS with a mean wavelength of 1578.2 nm, an output power of 132.8 mW, and a spectral linewidth of 52.6 nm without using any external spectral filters under 265-mW pump power. The high pumping efficiency of 50.1% is achieved experimentally. The design relaxes the danger in resonant lasing while enhancing the pumping efficiency and broadening the linewidth.

Stable L-band superfluorescent fiber source using one pump

We first demonstrate that by inserting an appropriate section of unpumped erbium-doped fiber (EDF) in an erbium-doped superfluorescent fiber source (SFS) of double-pass backward configuration, a stable L-band SFS can be achieved. The fiber-length arrangement of unpumped fiber are shown to have significant effects on the output properties of the L-band SFS. The spectral linewidth is broadened, and the variation of mean wavelength versus pump power is eliminated to achieve a wideband and mean wavelength stable L-band SFS by optimizing the fiber-length ratio of the pumped fiber length to the total fiber length. For a 19-m-long total EDF with fiber-length ratio of 0.84, a mean wavelength stable L-band SFS with a spectral linewidth of 49.6 nm, an output power of 46.3 mW, and a mean wavelength of 1583.20 nm was experimentally achieved.

双前向同步抽运的稳定L波段超荧光光纤光源特性

We investigate the characteristics of the dual-forward synchronously pumped L-band erbium-doped superfluorescent fiber source (SFS). The effects of pump ratio and fiber length arrangements on the output characteristics of the L-band SFS in terms of mean wavelength, spectral linewidth, and output power are analyzed. It is shown that the optimized pump ratio and fiber length arrangements provide broadening spectral linewidth and enhanced pumping efficiency, while the synchronous pump ensures stable mean wavelength operation. A new single-forward pumping scheme with a section of unpumped fiber is proposed to achieve a mean wavelength stable L-band SFS with a broadening linewidth of 50.4 nm and a pumping efficiency of 33.5%.

Resonantly pumped high power flat L-band erbium-doped superfluorescent fiber source

An all-single-mode-fiber L-band superfluorescent fiber source (SFS) with 1 W output power, 34.3 nm bandwidth (FWHM) and 54% optical conversion efficiency is constructed by seeding a high power erbium-doped fiber amplifier (EDFA) with a low power L-band ASE seed source to avoid parasitic lasing. The source is resonantly pumped by a high power C-band SFS peaked at 1545 nm.

Stable and wideband L-band erbium superfluorescent fiber source using improved bi-directional pumping configuration

We have proposed and demonstrated a wideband and wavelength stable L-band erbium-doped superfluorescent fiber source (SFS) using an improved double-pass bi-directional (DP-BD) pumping configuration with a segment of un-pumped fiber. The effects of the fiber length and pump power arrangements on the output characteristics of the L-band SFS are examined. Simulations and experiments show that the output characteristics of the L-band SFS are significantly improved by using an un-pumped fiber in the DP-BD pumping configuration. This designed configuration allows a wavelength stable L-band SFS operation with a broadening bandwidth of 52.6nm, an enhanced pumping efficiency of 47.5%, and a mean wavelength of 1580.42nm.

Wavelength stability optimization of L-band superfluorescent fiber source

A new bidirectional pumped configuration for an L-band erbium-doped superfluorescent fiber source is demonstrated. Data are presented showing that with this configuration, the mean wavelength variation with the pump power can be reduced to zero by optimizing the fiber length and the pumping ratio of forward to total pump power.

Polarized erbium-doped superfluorescent fiber source utilizing double-pass backward configuration

An erbium-doped superfluorescent fiber source utilizing a double-pass backward configuration is analyzed when a polarizer is inserted into an erbium-doped fiber to obtain polarized output light. Such a polarized configuration is simulated and experimentally confirmed to have the following characteristics: high polarization power conversion efficiency, pump-power-independent mean-wavelength operation, and low sensitivity to polarizer insertion loss.

Optimum Configuration and Design of L-Band Erbium-Doped Superfluorescent Fiber Source

This paper investigates the design and optimum configuration of 1480 nm pumped high-power L-band (1570–1610 nm) erbium-doped superfluorescent fiber sources (SFSs). These broadband incoherent sources may find important applications in such areas as sliced wavelength-division multiplexed (WDM) local-access networks, characteristic measurement for dense WDM components, laser spectroscopy, and fiber-optic sensor systems. We theoretically investigated and compared the characteristics of SFSs in terms of the mean wavelength, output power, and for various configurations of single-pass forward (SPF), single-pass backward (SPB), double-pass forward (DPF), and double-pass backward (DPB) structures. Among these configurations, the DPF scheme offered the highest output power with a good flat spectrum for an L-band fiber source. Both SPF and SPB configurations failed to implement the L-band SFSs. Though the DPB configuration could offer L-band SFS output power, the flat spectrum profile was difficult to establish. The results of this study may provide the configuration selection and design criteria of L-band erbium-doped SFSs.

Comparison of two flattening techniques on a double-pass erbium-doped superfluorescent fiber source for fiber-optic gyroscope

We experimentally compare the efficiency of two flattening techniques on the performances of a broad-band light source for fiber-optic gyroscope (FOG). The combination of a double-pass erbium-doped superfluorescent fiber source with a wavelength-selective reflector enables us to achieve the specifications needed for high-precision, navigational grade FOG: output power >18 mW, bandwidth of 30 nm, coherence length of 81 /spl mu/m.

Optical implementation of bipolar codes

The physical implementation of a bipolar encoding scheme suitable for WDM fiber-optic networks is reported with both experimental and theoretical results. The power spectrum of an erbium-doped superfluorescent fiber source is encoded, the bipolar correlations of the codes are verified, and rejection of multiple-access interference is demonstrated in a fiber-based testbed. Simulations of the correlation process identify key optical parameters and physical characteristics important to the design of future systems. A modification to the experimental testbed, made according to the theoretical analysis, results in improved correlation performance.

Comparison of the characteristics of double-pass erbium-doped superfluorescent fiber sources obtained from different flattening techniques

We investigate and compare the characteristics of erbium-doped superfluorescent fiber sources (SFS's) obtained from the use of different flattening techniques in double-pass forward (DPF) and double-pass backward (DPB) configurations. The intrinsic flattening technique consists of optimizing the length of the erbium-doped fiber. The extrinsic flattening methods include the addition of a samarium-doped fiber (SDF) and a fiber-Bragg-grating (FBG) notched filter at the output end separately to shape the SFS spectrum. Although intrinsically flattened DPF and DPB SFS's have a large output power of >34 mW, they are accompanied by an approximately 3-dB ripple. The FBG-flattened DPF and DPB SFS's can achieve a wide linewidth of 35 nm with a small ripple of approximately 1.7 dB and better pump-power-dependent mean-wavelength stability; SDF-flattened DPF and DPB SFS's are inferior because of the SDF's lossy spectrum.

Measurements of BER performance for bipolar encoding of an SFS

This paper reports on the measurements of bit error rate (BER) performance for a broad-band optical communications scheme that encodes the power spectrum of an erbium-doped superfluorescent fiber source (SFS) with bipolar equivalent codes. The proposed scheme, like spectrum-sliced wavelength division multiplexing (WDM), suffers from the excess noise associated with the detection of a thermal-like source. BER calculations based on measured testbed characteristics and a simple model are compared with BER measurements for one and two active users. In addition, the performance of a single user in the presence of broad-band spectral interference is investigated, giving a preliminary estimate of multiuser capacity. This paper discusses various solutions for increasing network capacity and performance, relevant to the proposed scheme as well as to wavelength division multiplexing (WDM).

Optical spectral amplitude CDMA communication

We report the first demonstration of bipolar coding techniques in the optical spectral domain for incoherent optical code division multiple access (CDMA) communication. Based on the modulation and detection principles that we have developed, the power spectrum of an erbium-doped superfluorescent fiber source was encoded using bipolar codes and decoded using an optical bipolar correlator. A CDMA testbed consisting of two encoders and one decoder was implemented with bulk optics and free-space transmission. Our measurements verify the correlations between the bipolar codewords and demonstrate the rejection of multiple access interference.