Doped Chalcogenide Fiber Research Articles

5 µm CW Ce3+-doped chalcogenide glass fiber laser with 17% slope efficiency.

Efficient room temperature mid-infrared laser action in a Ce3+-doped chalcogenide fiber was demonstrated. The fiber had a doped selenide glass core in an undoped sulfide glass cladding. The pump source was a CW Fe2+:ZnSe laser emitting at 4.14 µm. The optimized fiber length allowed obtaining up to 7 mW of 5.06 µm output with 17% slope efficiency at room temperature.

Five-micron Ce 3+ ion fiber laser

The spectral and temporal characteristics of a Ce 3+ -doped chalcogenide fiber laser pumped by a continuous Fe 2+ :ZnSe laser were investigated in this work.

High luminescence efficiency in Er3+-doped chalcogenide fiber with square inner-cladding

High-purity chalcogenide glasses and optimal fiber structure design are essential to enhance fluorescence lifetime and pump absorption efficiency in a chalcogenide-based fiber laser. Here, Er3+-doped As2S3 glasses, with a low –OH concentration of only 0.023 cm−1 (0.01 ppm), were prepared by the novel purification method, and the 4I11/2 level lifetime of purified glasses was increased successfully from 2.3 ms in unpurified glass to 4.8 ms in the purified glass. Furthermore, a special chalcogenide preform with square inner double cladding (S-DCF) was designed and fabricated via a novel extrusion-stacking method for the first time. Compared with circle inner double cladding fiber and single cladding fiber, the pump absorption efficiency is increased by 2–5 times, which fits well with the simulation result by the three-dimensional ray tracing method. All the results mentioned above demonstrated that the elimination of –OH and the optimized structure of S-DCF can improve the luminescence efficiency apparently and promote the development of mid-infrared fiber laser based on Er3+-doped chalcogenide glass.

Designing a W-type index praseodymium-doped chalcogenide fiber for strongly-efficient MIR Laser beyond 4 μm

This study is to propose an efficient design based on W-type index praseodymium (Pr 3+ )-doped chalcogenide fiber to enhance the emission of mid-infrared (MIR) wavelength beyond 4 μm. The advantage of the proposed design is to enlarge the core diameter to 32 μm under single mode guidance in order to restrict any impacts of nonlinearity and enhance the applied pumping power before the damage threshold. The effective mode field areas are about 979 μm 2 and 812 μm 2 at 4.5μm emitted MIR wavelength and 2.04μm pump wavelength, respectively. In the considered laser layout within this paper, a single pair of Fiber Bragg Gratings FBGs lay is adopted in the overlapping area of the emitting cross-sections parts of Pr 3+ ions in the transitions ( 3 F 2 , 3 H 6 → 3 H 5 and 3 H 5 → 3 H 4 ). This selected laser layout avoids the difficulties in the fabrication of concatenated FBGs in Pr 3+ -doped chalcogenide glass fibers. In addition, the efficiency of the laser can be also enhanced at this laser layout by emitting two photons in MIR wavelengths from one excited ion. The simulation outcomes indicate the possibility to exceed 61% of slope efficiency at 4.5 μm for 1dB/m loss in the fiber.

Photo-Writable Sulfide Glasses Used to Fabricate Core-Clad Fiber Doped with Pr3+ for Mid-IR Luminescence

With the ultimate goal of developing rare-earth doped chalcogenide fiber fabrication for sensing, amplification, and laser applications, a core/clad germanium-gallium sulfide fiber doped with Pr3+ has been fabricated. The compositions of the core and the clad were selected to ensure the positive ∆n by adding CdI2 and CsCl, respectively, in the GeS2-Ga2S3 matrix. The choice of these compositions was also justified from experimental parameters, including characteristic temperatures and viscosity. Moreover, the permanent photo writability of the sulfide glass family by a femtosecond laser is investigated from the perspective of Bragg grating photo-inscription. Structural investigations by Raman spectroscopy are presented and the effect of the Pr3+ rare-earth ion on the structure is underlined. Finally, the emission of the step-index fiber, made by the rod-in-tube technique between 3.1 µm and 5.5 µm (by pumping at 1.55 µm), is demonstrated.

Role of rare earth on the spectral properties of chalcogenide glassy alloys: A review

In this paper, recent results regarding rare earth element doped with chalcogenide glasses for optical gain media such as amplifiers and lasers are reviewed. Rare earth Chalcogenide glasses are formed when chalcogen elements (S, Se, Te etc.) are mixed with new additive elements (Ge, Ga, Sb, As etc.) and also with rare earth elements (Er, Dy, Pd, Pr etc.) from periodic table and prepared by melt quench technique (MQT). Rare earth element doped with chalcogenide glasses has been emerged as a suitable candidate for applications in the numeral passive and active. Among various materials, chalcogenide glasses show significant improvement in their emission properties in the optical communication range and spectroscopic properties. Finally, rare earth doped chalcogenide and optical fibers show potential for high power mid-infrared gain medium and their spectroscopic properties as well.

Core-clad terbium doped chalcogenide glass fiber with laser action at 5.38 μm

The core-clad Tb3+-doped Ga-Ge-As-Se/Ge-As-S chalcogenide glass fiber is fabricated and tested in laser experiment. To prepare the high-purity terbium doped Ga-Ge-As-Se core glass, the special multi-stage purification technique is developed. The 1050 ppmw Tb3+-doped core Ga3.2Ge24.9As15.3Se56.6 glass is characterized by an extra-low content of limiting hydrogen impurity, high stability against crystallization and strong broadband photoluminescence in the middle infrared range. The doped chalcogenide fiber has a total diameter of 400 μm, a core diameter of 18 μm, and minimum optical losses of 3 ± 0.3 dB/m at a wavelength of 7.1 μm. Using a Tm3+ 1.98 μm fiber laser as a pump source, the threshold of 5.38 μm lasing with spike structure was reached in chalcogenide fiber for the first time.

Milliwatt-Level Spontaneous Emission Across the 3.5–8 µm Spectral Region from Pr3+ Doped Selenide Chalcogenide Fiber Pumped with a Laser Diode

A spontaneous emission fiber source operating in the mid-infrared (MIR) wavelength range from 3.5 to 8 µm is demonstrated for the first time at output power levels of at least 1 mW. The source is a Pr3+-doped selenide chalcogenide, multimode, glass fiber pumped with commercially available laser diodes operating at 1.470 µm, 1.511 µm and 1.690 µm. This MIR spontaneous emission fiber source offers a viable alternative to broadband mid-infrared supercontinuum fiber sources, which are comparatively complex and costly. The MIR emission wavelength range is significant for molecular sensing applications across biology and chemistry, and in medicine, agriculture, defense, and environmental monitoring.

Dy3+ doped GaGeSbSe fiber long-wave infrared emission

We report on the mid-wave infrared (MWIR) and long-wave infrared (LWIR) emissions of a 1000 ppm Dy3+ doped Ga5Ge20Sb10Se65 chalcogenide fiber. Following a short-wave infrared (SWIR) optical pumping at 0.92, 1.12 and 1.32 μm using commercial laser diodes, LWIR luminescence around 7.3 μm (6H7/2 → 6H9/2 transition) was recorded for the first time to the best of our knowledge along with MWIR emissions around 4.3 μm and 5.4 μm with a Dy3+ doped Ga5Ge20Sb10Se65 fiber. Frequency dependent spectroscopic investigation clearly shows that this LWIR luminescence originates from the 6H7/2 manifold. Spectroscopic properties of this Dy3+ doped material and the comparison with its equivalent sulfide Dy3+:Ga5Ge20Sb10S65 glass are presented.

Optical fibers based on special pure Ge20Se80 and Ge26As17Se25Te32 glasses for FEWS

For middle infrared fiber-optic evanescent wave spectroscopy, the single-index Ge20Se80 and Ge26As17Se25Te32 glass fibers are fabricated by a crucible method. The background optical loss in the Ge20Se80 fiber is 1.5 dB/m in the 5–7.8 μm spectral range (minimum is 0.9 dB/m at 7.1 μm), and that in the Ge26As17Se25Te32 fiber is 1 dB/m in the range of 5.5–8.5 μm (minimum is 0.65 dB/m at 6.6 μm). On the basis of these chalcogenide glass fibers, the middle infrared sensors with the different geometry of sensitive zone (straight, U-shaped form, one loop, two loops) are manufactured. By the example of diesel fuel, it is shown that when passing from the straight section of the sensitive zone to the double loop, the integrated intensity of the absorption bands increases by an order of magnitude. The method of regression analysis was applied to plot a calibration dependence for the additive concentration in diesel fuel in the range of 0.1–1 vol% using a U-shaped fiber sensor. The possibility of using the luminescent Pr(3+)-doped chalcogenide fiber as the source of mid-IR radiation for recording the absorption spectra of substances absorbing in the spectral range 4–5 μm is demonstrated.

Experimental and numerical investigation of mid-infrared laser in Pr3+-doped chalcogenide fiber**Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61605095), the Natural Science Foundation of Zhejiang Province, China (Grant No. LY19F050004), the Natural Science Foundation of Ningbo City (Grant No. 2015A610038), the Open Fund of the Guangdong Engineering Technology Research and Development

We report on a chalcogenide glass fiber doped with Pr3+ that can be used for commercialized 1.5- and 2- laser excitations by emitting broadband – fluorescence, which is extruded into a preform and then drawn into a step-index fiber. The spectroscopic properties of the fiber and glass are reported, and the mid-infrared fiber lasers are also numerically investigated. Cascade lasing is employed to increase the inversion population of the upper laser level. The particle swarm approach is applied to optimize the fiber laser parameters. The output power can reach 1.28 W at 4.89- wavelength, with a pump power of 5 W, excitation wavelength at , Pr3+ ion concentration at 4.22 ×1025 ions/m3, fiber length at 0.94 m, and fiber background loss at 3 dB/m.

7 to 8 µm emission from Sm3+ doped selenide fibers.

We report on the observation of the long wave-infrared (LWIR) emission centered at 7.3 µm of Sm3+ doped chalcogenide fibers. The chemical composition of the selenide glass host matrix (Ga5Ge20Sb10Se65) enables the drawing of 500 ppm and 1000 ppm Sm3+ doped fibers. By means of conventional glass elaboration methods, these Sm3+ doped fibered materials exhibit a significant emission band from 6.5 to 8.5 µm with a maximum emission around 7.3 µm whether they are excited at 1.45 µm or at 2.05 µm. Absorption spectra, Judd-Ofelt analysis, NIR, MWIR and LWIR luminescence spectra are presented and discussed.

Modeling of resonantly pumped mid-infrared Pr3+-doped chalcogenide fiber amplifier with different pumping schemes.

We propose a model for resonantly pumped Pr3+-doped chalcogenide fiber amplifiers, which includes excited state absorption and the full spectral amplified spontaneous emission spanning from 2 μm to 6 μm. Based on this model, the observed near- and mid-infrared photoluminescence generated from Pr3+-doped chalcogenide fiber is explained. Then the output properties of a 4.1 μm resonantly pumped Pr3+-doped chalcogenide fiber amplifier are simulated in both co- and counter-pumping schemes. Results show that the 4.1 μm counter-pumped fiber amplifier can achieve a power conversion efficiency (PCE) of over 62.8% for signal wavelengths ranging from 4.5 μm to 5.3 μm. This is, to our best knowledge, the highest simulated PCE for a Pr3+-doped chalcogenide fiber amplifier.

Theoretical Modeling of 4.3 μm Mid-Infrared Lasing in Dy3+-Doped Chalcogenide Fiber Lasers

We theoretically investigate a Dy3+-doped chalcogenide fiber lasers operating at 4.3 μ m based on the rate equations and propagation equations. The two main pump bands for 1319 and 1707 nm corresponding to the 6 H 15/2→6 H 9/2 and 6 H 15/2→6 H 13/2 transitions are discussed in detail. The predicted maximum slope efficiencies are determined to be ∼7.8% and ∼15.1% for the two pumping wavelength, respectively. Besides, the variety of laser performance has been systematically analyzed when the pump configurations, fiber length, fiber loss are varied. This numerical analysis might be useful to explore the 4.3 μ m lasing operation for the mid-infrared chalcogenide fiber lasers in future.

IR emitting Dy3+ doped chalcogenide fibers for in situ CO2 monitoring in high pressure microsystems

This paper reports the carbon dioxide detection in silicon-Pyrex high pressure microfluidic devices mimicking geological conditions encountered in deep saline aquifers using an in situ infrared optical sensor. The middle infrared source inserted inside the microchannel is based on infrared emission from Dy3+ sulfide glass fibers. The broad emission of the Dy3+ doping in infrared fibers is used to directly probe the CO2 thanks to the perfect overlap between the rare earth emission centered at 4.4μm and the CO2 absorption band located at 4.3μm. CO2 and water were clearly distinguished when using segmented flow on chip at pressures ranging from 4.5 to 6MPa. These results demonstrate the feasibility of the infrared optical detection of other gases displaying absorption bands in the middle infrared domain for further developments of gas sensors, which can find applications in geological media monitoring and microfluidics.

Fiber evanescent wave spectroscopy based on IR fluorescent chalcogenide fibers

Chalcogenide glasses, owing to their transparency in the infrared window and the appropriate solubility of rare earth, allows the generation of middle infrared (mid-IR) radiation from a near infrared or visible pumping source. These emitted mid-IR broad bands can probe the vibrational modes of several molecules, e.g. CH, CO or CCl. Relying on this principle, a mid-IR optical sensor using the mid-IR fluorescence of Pr3+: Ga-Ge-Sb-S fibers has been developed. The detection principle is based on Fiber Evanescent Wave Spectroscopy (FEWS). The spectroscopic characterization of praseodymium ions (Pr3+) was performed in the near and mid-IR and is discussed on the basis of comparison with Judd–Ofelt calculations. The broad emission spectrum of the Pr3+: Ga-Ge-Sb-S fiber from 4 to 5μm could enable the monitoring of multiple pollutants. In this study, chloroform detection is carried out via a novel technique derived from FEWS. In this way, an infrared sensor was developed, composed of a pumping source in near-IR, a mid-IR detector and a tapered Pr3+: chalcogenide fiber to enhance the detection sensitivity. These results demonstrate for the first time the feasibility of detecting molecules by FEWS using the mid-IR fluorescence emitted by rare earth ions doping chalcogenide fibers. This method is an effective alternative to the classical FEWS system, as RE doped chalcogenide fibers have the advantage of being a compact mid-IR source.

Highly efficient cascaded amplification using Pr(3+)-doped mid-infrared chalcogenide fiber amplifiers.

We computationally investigate cascaded amplification in a three-level mid-infrared (IR) Pr(3+)-doped chalcogenide fiber amplifier. The overlap of the cross-sections in the transitions (3)H(6)→(3)H(5) and (3)H(5)→(3)H(4) enable both transitions to simultaneously amplify a single wavelength in the range between 4.25 μm and 4.55 μm. High gain and low noise are achieved simultaneously if the signal is at 4.5 μm. We show that 45% of pump power that is injected at 2 μm can be shifted to 4.5 μm. The efficiency of using a mid-IR fiber amplifier is higher than what can be achieved by using mid-IR supercontinuum generation, which has been estimated at 25%. This mid-IR fiber amplifier can be used in conjunction with quantum cascade lasers to obtain a tunable, high-power mid-IR source.

Wavelength conversion in Er(3+) doped chalcogenide fibers for optical gas sensors.

We report for the first time the conversion of incoherent infrared light around 4.4µm into a near-infrared signal at 810nm in erbium-doped GaGeSbS fibers and bulk glass samples. This energy conversion is made possible by pumping erbium doped chalcogenide samples at 982 nm and simultaneously exciting them with a 4.4µm infrared signal. This result paves the way for the development of an "all-optical" gas sensor able to detect various gas traces using a remote detection based on commercial silica fibers.

IR Fiber Optics-An Introduction

During the past many years of the development of IR fibers there has been a great deal of fundamental research designed to produce a fiber with optical and mechanical properties close to that of silica. We can see that today we are still far from that Holy Grail but some viable IR fibers have emerged which as a class can be used to address some of the needs for a fiber which can transmit greater than 2 μm. Yet we are still limited with the current IR fiber technology by high loss and low strength. Nevertheless, more applications are being found for IR fibers as users become aware of their limitations and, more importantly, how to design around their properties. There are two near-term applications of IR fibers; laser power delivery and sensors. An important future application for these fibers, however, may be more in active fiber systems like the Er and Pr doped fluoride fibers and emerging doped chalcogenide fibers. As power delivery fibers, the best choice seems to be hollow waveguides for CO2 lasers and either SC sapphire, germanate glass, or HGWs for Er: YAG laser delivery. Chemical, temperature, and imaging bundles make use mostly of solid -core fibers. Evanescent wave spectroscopy (EWS) using chalcogenide and fluoride fibers are quite successful. A distinct advantage of an IR fiber EWS sensor is that the signature of the analyte is often very strong in the infrared or fingerprint region of the spectrum. Temperature sensing generally involves the transmission of blackbody radiation. IR fibers can be very advantageous at low temperatures especially near room temperature where the peak in the blackbody radiation is near 10 □m. Finally, there is an emerging interest in IR imaging using coherent bundles of IR fibers. Several thousand chalcogenide fibers have been bundled by Amorphous Materials (Garland, TX) to make an image bundle for the 3 to 10 □m region.