Optical Amplifier Applications Research Articles

Synthesis and characterization of erbium silica glass and glass-ceramics for potential low-emissivity coating applications

Silica glasses co-doped with varying concentrations of Er3+ (0.8, 1.5, 4, and 8 mol %) were fabricated employing the sol-gel technique. The effects of erbium concentration were evaluated through several characterization techniques, including X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV-visible transmission spectroscopy, and photoluminescence analysis. The incorporation of erbium ions significantly altered the structural, optical, and photoluminescence properties of the doped glasses. XRD analysis revealed the presence of SiO2 in both tetragonal and hexagonal forms, along with Er2SiO5 crystalline phases. SEM images showed irregular rod-shaped structures with agglomeration and micro-flake cubic shapes. FTIR spectroscopy provided insights into the structural characteristics of the materials. Notably, the optical band gap energy of the glassy films increased, accompanied by fluctuating Urbach energy and a slight reduction in the refractive index, attributed to structural changes within the glass network. Photoluminescence spectra indicated strong emissions at 523 and 543 nm, corresponding to the transitions 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2, respectively. Additionally, a notable near-infrared emission at 1532 nm was observed, linked to the transition 4I13/2 → 4I15/2. The color coordinates of the produced glasses were found to be near the green or yellow regions, suggesting potential applications in optical amplifiers, lasers, and low-emissivity coatings.

Synthesis and characterization of Er2O3-doped Y2O3 nanoparticle incorporated optical fiber for use as optical amplifier

Erbium oxide (Er2O3)-doped optical fibers (EDF) are well-known for their applications in optical amplification at 1550 nm. In this study, we present the synthesis of Er2O3-doped yttrium oxide (Y2O3) nanoparticles (NPs) using a homogeneous coprecipitation technique and their integration into optical fibers for enhanced optical amplification. A series of NP samples with varying Y/Er molar ratios were synthesized to identify the optimal composition for incorporation into optical fibers. X-ray diffraction (XRD) analysis revealed that the nanoparticles crystallize in a cubic geometry (space group Ia3) with crystallite sizes ranging from 20 to 41 nm. These sizes increased approximately to 90 nm as the calcination temperature was raised from 1000°C to 1400°C. Field emission scanning electron microscopy (FESEM) corroborated the XRD results, while high-resolution transmission electron microscopy (HRTEM) confirmed the crystalline structure and an average particle size of approximately 100 nm. Photoluminescence studies showed that emission and excitation intensities were functions of the Y/Er molar concentration ratio and calcination temperature, with the lifetime extending up to 6.86 ms for a sample with a 0.25:0.01 Y2O3:Er2O3 ratio calcined at 1400°C. To assess the performance of the synthesized NPs, an optical preform was prepared using the Vapor Phase Delivery (VPD) method combined with the Solution Doping (SD) technique. The preform was then drawn into fiber, and its amplification performance was evaluated. The resulting fiber demonstrated efficient amplification with a gain of 14.9 dB with respect to 0 dBm input signal at 1550 nm under 150 mW pump power from 9 m active fiber, indicating its potential as a gain medium for constructing erbium-doped fiber amplifiers (EDFAs).

Supermode lasing and light amplification in multicore bismuth-doped fiber

Multicore fibers are promising structures with specific light propagation properties, which can be managed to benefit several applications in optical communications, fiber lasers and amplifiers, high-resolution imaging, and fiber-based sensors. The current use of multicore fibers in laser technology is mainly focused on in-phase coherent beam combining in far-field regions (out-cavity) using bulk optical elements. However, this approach is challenging in terms of the power scalability of all-fiber lasers (intra-cavity), particularly with using low-gain media, where it is needed to provide mode-coupling (supermode propagation) stability along relatively long lengths. Here, we report a conceptual design and fabrication of a multicore bismuth-doped fiber that is capable of achieving light amplification and stable lasing in the E-telecom band inside the cavity using the supermode selection approach. By analysis of experimental and simulation data, it was found that the employment of the proposed design of a Bi-doped fiber provides a considerable advantage over the single-core fiber in terms of laser performance (output power, slope efficiency) in the cladding-pumped configuration. These results open up new opportunities for further advancement of the optical fiber technology towards efficient bismuth-doped fiber-integrated amplifiers and lasers for the O+E+S+C+L+U-telecom bands, which may find important applications, especially for the development of next-generation multiband optical transmission systems.

Recent Advances and Applications of Semiconductor Optical Amplifiers

This paper describes the recent advances in device designs and optical transmission applications of semiconductor optical amplifiers (SOA). The device advances described are quantum-dot-based SOA and photonic-integrated circuits using SOA. The use of nonlinear properties of SOAs in high-speed optical transmission is discussed.

Exploring the optical properties of the 1.53 μm emission in Er3+-doped glass, anti-glass and ceramic in TeO2 - Ta2O5 – Bi2O3 system

A series of 80TeO2 - 10Ta2O5 – 10Bi2O3 glasses, anti-glasses and ceramics doped with different concentrations of Er₂O₃, ranging from 0.25 % to 2 % mol, were synthesized to explore their structural transformation and optical properties. The maximum solubility of Er₂O₃ was identified at 1.25 % mol, beyond which the glass transitioned from an amorphous to a crystalline structure. The anti-glasses and ceramics obtained from the heat treatment of the parent glasses were also studied to gain insights into their optical properties. This study reveals a direct relationship between Er3+ ions concentration and full width at half maximum (FWHM) of photoluminescence spectra. The increase in Er3+ ions concentration correlates with a rise in FWHM, indicative of spectral broadening. Anti-glass exhibits a higher emission intensity, followed by ceramic and then glass, reflecting their distinct structural properties. Anti-glass doped with 1 % mol Er2O3 shows an FWHM over 130 nm under 578 mW pumping. The lifetime of the excited state 4I13/2 increases with the Er2O3 content in the anti-glass and the ceramic, with a notable decrease at 1 % mol Er2O3 ions for both materials, while in glass, the decrease is observed at 0.5 %. Emission cross-sections decrease with increasing Er3+ ions concentration and power, influenced by factors like thermal effects and saturation. The Judd-Ofelt theory highlights structural differences, with glasses having a more disordered structure and with an increase in the Ω₆ parameter across all materials, implying enhanced electric dipole line strength and spontaneous emission probability with higher Er₂O₃ content. Overall, this comprehensive study provides valuable insights into the optical behavior of Er3+ ions in these materials, essential for applications in laser design and optical amplifiers.

Quantum size luminescence effect in local field enhancement of Ag NP added Er3+ glass system

This research investigates the effect of silver (Ag) addition on the photoluminescence enhancement properties of 20Li2O–5Bi2O3-(74-x)TeO2–1Er2O3-xAg glass samples, aiming to optimize luminescence for applications in optical amplifiers and laser technologies. The enhancement of luminescence properties for both upconversion 4S3/2 → 4I15/2 green band and 4F9/2 → 4I15/2 red peak luminescence observed are analyzed by quantum yield ξ and relative intensity enhancement (I/Io) parameters. The enhancement on green luminescence properties are observed with high ξgreen and I/Iogreen at x < 1 mol% which can be explained within the cavity quantum electrodynamics (CQED) framework due to very low dipolar localized surface plasmon mode volume Veff (∼10–20 × 10−22 m3) allowing stronger quantum size luminescence effect. Meanwhile, the quenching of ξgreen (0.61) at x≥ 1 mol% may indicate the weaker quantum size luminescence effect. An anomalous enhancement on red luminescence properties with high ξred (2.07) and I/Iored (1.79) at x = 1.25 mol% cannot be explained by CQED framework but from phonon-assisted energy transfer (PET) mechanism occurred due to structural changes. The near-field and far-field parameters of AgNP are simulated. Results demonstrated stronger near field electric field distribution enhancement at x = 0.5 mol% and x = 0.75 mol%. This suggests that an optimal AgNP radius exists for promoting the quantum size luminescence effect in our glass samples, falling within the range of 50.00–60.00 nm. Further supporting this conclusion, theoretical calculations using light intensity scattering efficiency (Qsca) revealed the highest values between 50.00 and 70.00 nm of AgNP radius in our glass samples.

Crystal growth, structure, spectral and thermal properties of ScxY1-xCOB single crystals

Yttrium calcium oxyborate (YCOB) crystals are excellent nonlinear optical crystals. To enhance the thermal properties of YCOB crystal, Sc-doped YCOB crystals, denoted as ScxY1-xCa4O(BO3)3 (x = 0.1 and 0.2) were grown using the Czochralski method along the b-direction. Various measurements, including X-ray powder diffraction, rocking curve analysis, inductively coupled plasma-optical emission spectroscopy (ICP-OES), transmission spectroscopy, density measurements, and thermal property assessments, were conducted to evaluate the characteristics of the ScxY1-xCOB crystals. The results indicated that ScxY1-xCOB crystals have an isostructural arrangement like YCOB, with segregation coefficients of approximately 0.2. The full width at half maximum (FWHM) values of the rocking curves of the ScxY1-xCOB (x = 0.1 and 0.2) crystals are 33.9″ and 29.3″, respectively. Furthermore, the specific heat, thermal diffusion coefficients and thermal conductivity of the ScxY1-xCOB crystals were examined in the temperature range of 298–573 K, which were found to be higher than those of pure YCOB. These high-quality ScxY1-xCOB crystals are expected to serve as suitable nonlinear optical crystals media for optical parametric chirped pulse amplification (OPCPA) applications.

Spectroscopic characteristics and gain cross-section profiles of erbium-doped boro-tellurite glasses for optical amplifier applications

A series of glass compositions (60-x) B2O3–10TeO2–15BaCO3–15MgF2–xEr2O3 with diverse quantities of erbium ions (Er3+) was synthesized using the melt quenching method and the samples were subjected to thorough characterization to explore their optical and structural properties. In order to ascertain the amorphous nature of the glass and acquire a deeper understanding of its chemical bonding, conventional methods of characterization, such as X-ray diffraction and Fourier transform infrared spectroscopy, were utilized. The Judd-Ofelt intensity parameters were computed using the absorption spectra of glasses doped with Er3+, providing vital information about the local environment and coordination of Er3+ ions in the glass matrix. The glasses underwent the collection of near -infrared (NIR) emission spectra. Following this, an analysis was carried out to look into and understand the spectral properties, emission cross-section, and gain coefficient parameters of the glasses. The spectra obtained discernible characteristics, notably a significant near-infrared (NIR) band associated with the transition between the 4I13/2 and 4I15/2 states. This band was seen to have a central wavelength of 1530 nm. This emission band spanned the wavelengths commonly used in optical communication systems (S + C) -bands, making these glasses suitable candidates for applications such as wavelength division multiplexing (WDM). These results suggest that the boro-tellurite glass may have potential use in photonic devices designed for near-infrared applications, including optical communication systems.

Spectroscopic properties of Er3+-doped barium phosphate glasses for optical gain media

Barium metaphosphate glasses (PBaLa) doped with erbium (Er3+) ions have been prepared by melt quenching method and studied their optical, structural characteristics by using FT-IR, absorption, radiative de-excitation spectra, decay curves and up-conversion measurements. Judd-Ofelt (Ωλ, λ = 2,4 and 6) parameters have been determined using the absorption transitions of the Er3+(1.0 mol %)-doped glasses which are in turn taken to predict the radiative characteristics that include branching ratio (βR), radiative emission probability (AR) and lifetime (τR) of some important fluorescent levels of Er3+:glasses. Visible emission spectra measured under 378 nm excitation reveals three emission transitions at 663 (4F9/2 → 4I15/2), 547 (4S3/2→ 4I15/2) and 524 nm (2H11/2 → 4I15/2) corresponding to Er3+ ions. Among these, the green emission at 547 nm is relatively intense. Near-Infrared emissions were measured by exciting at 980 nm which exhibits broad emission at 4I13/2→ 4I15/2 (1.53 µm). The stimulated emission cross-section (σemi), FWHM and gain bandwidth (σemi× FWHM) were predicted to be 13.58 × 10-21 cm−2, 59 nm and 801.2 cm3, respectively, for PBaLaEr1.0 glass. The lifetime of 4I13/2 level has been shortened from 2.53 to 0.8 ms with an increase in Er3+ ions concentration from 0.1 to 2 mol %. NIR to visible up-conversion has also been measured for various concentrations of Er3+-doped PBaLaEr glasses with 980 nm excitation. These findings indicate that the Er3+-doped PBaLaEr glasses can be considered for waveguide laser and optical amplifier applications at 1.53 µm.

The role of tungsten oxide in Er3+-doped bismuth-germanate glasses for optical amplification in L-band

A series of novel Er3+-doped bismuth-germanate glasses containing different tungsten concentrations with a molar composition of 97.5[(75 − x)GeO2–25Bi2O3–(x)WO3]–2Sb2O3–0.5Er2O3 (x = 5, 10, 15, 20, and 25 mol%) were fabricated. Their thermal properties are measured by differential scanning calorimetry. A structural investigation by Raman spectroscopy suggested that changes occurred in the glass network by WO3 incorporation. By laser excitation at 980 nm, a strong emission from Er3+ ions at 1532 nm is observed, while the WO3 addition caused changes in the emission spectra. The emission cross-section spectra of Er3+ are calculated by both McCumber and Füchtbauer–Ladenburg theories and their comparison showed these theories yielded slightly different results, but in both cases, the calculations showed that a gain signal in L-band can be achieved when 30% of the Er3+ ions are at the excited state. This study proves that the Er3+-doped bismuth-germanate glasses are suitable for optical fiber amplifier applications operating at C- and L-band.

Efficient structural manipulation of PbS in Er-doped silica optical fibers for enhanced amplification systems

In active silica optical fibers, improving the solubility and uniformity of non-concentration-quenching luminescence centers is a key strategy to achieve high gain fiber amplifiers. Herein, we report a novel Er-doped silica optical fiber (EDF) modified by PbS semiconductor incorporation for the first time. Owing to the bridge role of PbS, Er2O3 nanofilms deposited on the substrate via atomic layer deposition (ALD) have porous and loosely layered network structures with an increasing number of ALD-PbS layers. Subsequently, during the high-temperature fiber preparation process, this loose porous structure aids the dissolution and provides an optimal local environment of Er3+ ions in the silica matrix. As a result, the maximum phonon energy of the silica network for PbS/Er co-doped silica optical fiber (PEDF) is reduced, resulting in an increase of the Er3+ ion fluorescence lifetime, approximately 11.455 ms. Furthermore, we achieved 34 dB maximum gain of PEDF sample with the lowest noise figure of 3.9 dB at 1.5 μm. The gain bandwidth over 20 dB of PEDF is approximately 46 nm, which is nearly 44% higher than that of EDF. These results indicate that the PEDF prepared by structural manipulation has great potentials in optical fiber amplifier and laser applications.

Tri-doped Ln3+ ions in barium zinc borate glasses: Luminescence behavior at room and cryogenic temperatures

The research work carried out in the paper reports on the effect of BaO and tri doped Er3+, Tb3+, and Gd3+ ions on luminescence characteristics in zinc borate glasses. The work emphasizes the effect of BaO on tri-doped lanthanide ions in borate glasses. The addition of 5 mol% BaO content in the glasses shows more non-bridging oxygens and decreases with addition of BaO content (10 mol%). Glasses show emissions at 311 nm, 543 nm, and 1540 nm for Gd3+, Tb3+, and Er3+ ions, respectively. The Judd-Ofelt method was applied to bring out the significance of the oscillator strength of Tb3+ ions. Higher value of Ω2 was observed in the present glasses indicating their rare-earth covalency is more around Tb3+ ions. Low-temperature luminescence studies were studied for the T2 glass sample for Tb3+ ions. Cryogenic temperature luminescence studies were studied to bring out the significance of 5D4 to 7FJ (J = 3, 2, 1, 0) which is not normally visible at room temperature. The energy is transferred from the Gd3+ to the Tb3+ ions by the Gd3+ ions acting as sensitizers, which helps to adjust the excitation wavelength. Yellowish-green-emitting glasses were observed by illuminating UV light and verified as such from the CIE diagram. The prepared glasses are potential candidate for visible-emitting around yellowish-green colour emitting capability and NIR emitting optical devices and broadband amplifier applications.

Tunable-wavelength photoluminescence of a flexible transition metal doped oxide phosphor thin film

Near-infrared luminescence phosphors are key material basis to potential applications for light sources and optoelectronic devices. In particular, it is vital to tune the luminescent properties of these phosphors in a flexible and controllable manner. Here, we demonstrate that a flexural strain originated from bending can be used to modulate the photoluminescence of freestanding Ni2+ doped SrTiO3 membranes. The bent membranes show remarkable red-shift emissions, arising from the variations of the symmetry of host materials and the local crystal fields around the Ni2+ ions. In addition, the phosphor films show a reversible and stable wavelength modulation with remarkable anti-fatigue characteristics after 104 bending cycles. These results provide a potential routine to develop flexible strain-tunable devices for applications in optical amplifiers and other optoelectronics.

Ultra‐broadband and thermally stable NIR emission in Bi‐doped glasses and fibers enabled by a metal reduction strategy

AbstractBismuth (Bi)‐doped glasses with broadband near‐infrared (NIR) emission have been drawing increasing interest due to their potential applications in tunable fiber lasers and broadband optical amplifiers. Yet, the implementation of highly efficient and ultra‐broadband Bi NIR emission covering the whole telecommunication window remains a daunting challenge. Here, via a metal reduction strategy to simultaneously create a chemically reductive environment during glass melting and enhance the local network rigidity, a super broadband (FWHM ≈ 600 nm) NIR emission covering the entire telecommunications window with greatly enhanced intensity was achieved in Bi‐doped germanate glasses. More importantly, due to the excellent thermal stability, the super broadband Bi NIR emission can be well retained after the glass was drawn into an optical fiber. Furthermore, the transmission loss of 0.066 dB/cm at 1310 nm and an obvious broadband amplified spontaneous emission spectrum spanning a range of 1000–1600 nm were observed in this fiber. This work can strengthen our comprehension of the complicated Bi NIR luminescence behaviors and offer a feasible and universal way to fabricate tunable fiber lasers and broadband optical amplifiers based on Bi‐doped multicomponent glasses.

Formation of Au@Ag Bimetallic Nanoparticles via Ion Implantation and Its Effects on Boosting the Near-Infrared Emission of Er3+ Ions in Germanate Glass for Applications in Optical Amplifiers

In this work, germanate glasses of composition 59GeO2-41PbO in mol% doped with Er3+ ions were synthesized using the melt-quenching route. Au and Ag nanoparticles and Au@Ag bimetallic nanoparticles were formed on the surface of the germanate glasses by ion implantation followed by thermal treatments. X-ray diffraction patterns confirmed the amorphous structure of the implanted glasses. Molecular dynamics was used to simulate the GeO2–PbO glass structure. Surface plasmon resonance bands centered at 486, 537, and 574 nm, obtained through ultraviolet–visible absorption spectra, supported the formation of Ag, Au, and Au@Ag nanoparticles, respectively. Transmission electron microscopy (TEM) revealed the presence of spherical Au and Ag nanoparticles as well as the presence of nonspherical Au@Ag bimetallic nanoalloys. Refractive index n and extinction coefficient k were measured by ellipsometry. Judd–Ofelt theory was applied to evaluate the phenomenological intensity parameters Ωλ(λ = 2,4,6) , radiative parameters, and stimulated emission cross-sections for glasses doped with Er3+ and implanted with Au @Ag bimetallic nanoalloys. Efficient boosting of the near-infrared emission for the 4I13/2 → 4I15/2 transition was observed in the glass doped with Er3+ ions due to the presence of Au@Ag bimetallic nanoalloys. The possible cause of this improvement in luminescent intensity was attributed to the strong local field effect due to the efficient synergy between Au@Ag bimetallic nanoalloys and the Er3+ ions. The results obtained in this work indicate that the vitreous system GeO2–PbO glass doped with Er3+ ions and with the incorporation of Au@Ag bimetallic nanoalloys via ionic implantation exhibit excellent spectroscopic properties compared to other vitreous host glasses doped with the Er3+, indicating its potential applications in optical amplifiers.

Broadband infrared emission of Pr3+-doped BiLa2O4.5 phosphor for optical amplifier applications

Today, the development of broadband optical amplifiers for optical communication applications continues to motivate research into rare earth ion (RE)-activated near-infrared (NIR) emissive materials. Pr3+-doped BiLa2O4.5 phosphors were prepared via the facile solid-state reaction. The phase formation, structural characteristics, and broadband NIR emission of Pr3+ ions are presented. Unlike commonly reported materials activated by Pr3+ ions, 1320 nm luminescence, that usually applied as an amplifier technology in O-band optical communication, has not been detected in BiLa2-2xPr2xO4.5 (x = 0.005–0.05). However, BiLa2-2xPr2xO4.5 shows a broad 1D2→1G4 emission (1400 nm–1550 nm) extending over the E−, S-, and C- bands in optical communication, and its full-width at half-maximum (FWHM) can reach 143 nm at room temperature. Pr3+-doped BiLa2O4.5 is expected to serve as a potential candidate for amplifier materials in E− and S-band communication system technologies. The quenching of the 1320 nm luminescence in BiLa2-2xPr2xO4.5 was discussed via the energy gap based on the high-energy phonons of the host. The maximum doping concentration to achieve maximum near-infrared luminescence (1400 nm–1550 nm band) in BiLa2-2xPr2xO4.5 is x = 0.03. The concentration quenching and luminescence mechanism are discussed via cross-relaxation.

Improved Fluorescence and Gain Characteristics of Er-Doped Optical Fiber with PbS Nanomaterials Co-Doping.

Er-doped optical fiber (EDF) with ultra-broad gain bandwidth is urgently needed given the rapid advancement of optical communication. However, the weak crystal field of the host silica glass severely restricts the bandwidth of traditional EDF at 1.5 μm. In this study, we theoretically explored the introduction of PbS nanomaterials in the silica network assisted with the non-bridging oxygen. This can significantly increase the crystal field strength of Er3+ ions in the local structure, leading to their energy level splitting and expanding the fluorescence bandwidth. Additionally, the PbS/Er co-doped optical fiber (PEDF) with improved fluorescence and gain characteristics was fabricated using modified chemical vapor deposition combined with the atomic layer deposition technique. The presence of PbS nanomaterials in the fiber core region, which had an average size of 4 nm, causes the 4I13/2 energy level of Er3+ ions to divide, increasing the fluorescence bandwidth from 32 to 39 nm. Notably, the gain bandwidth of PEDF greater than 20 dB increased by approximately 12 nm compared to that of EDF. The obtained PEDF would play an important role in the optical fiber amplifier and laser applications.

Co-Doping Effect of Bismuth Ions on the Gain Characteristics of Er-Doped Silica Optical Fiber

By examining the spectral and amplification characteristics of Er-doped silica fiber (EDSF) and Bi/Er co-doped silica fiber (BEDSF), an active doped silica fiber with broadband- and flat-gain is investigated. Results show that the bandwidth of BEDSF with a gain greater than 20 dB is approximately 50 nm. Moreover, in the entire C-band, the gain of BEDSF exceeds 26 dB with a fluctuation range of approximately 2 dB. The excellent performance may mainly come from the role of bismuth ions. Further analysis demonstrates that the emission and gain cross-sections are enhanced, the bandwidth is broadened, and the flatness is also optimized by co-doping Bi ions. The fluorescence lifetime of Er3+ is lengthened by 1.82 ms, illustrating that there may exist energy transfer from Bi-related active centers to Er3+. The results indicate that the proposed BEDSF has significant potential application in optical fiber amplifiers, lasers, sensors, and so on.

Multiple CPA−laser points and anisotropic reflection resonances in PT−symmetric Rudin-Shapiro photonic multilayers

We theoretically explore the CPA−LPs (coherent-perfect-absorber−laser points) directional dependence of reflected light waves at the in quasi-periodicity photonic multilayers. Two dielectric slabs with different refractive indices arrange alternately to form the Rudin-Shapiro (RS) photonic multilayers and the whole system satisfies parity-time (PT) symmetry simultaneously. The PT−symmetric RS structures support optical fractal resonant states and can also localize the electric field of transmission modes greatly. The optical fractal resonances may incorporate and CPA−LPs are induced by modulating the light frequency and the gain/loss factor of materials. The complex phase of reflection coefficient and the electric filed distribution are anisotropic for the left and right incident light waves. The anisotropy is especially remarkable near the CPA−LPs. The CPA−LPs could be regulated by the incident angle and the LPs quantity increases with the increase of the generation number of RS sequence as well. This study has potential applications of optical amplifiers and lasers.

Broadband Optical Amplification of PbS Quantum‐Dot‐Doped Glass Fibers

The rapid development of global telecommunication, cloud computing, big data, consumer electronics create increasing demands to expand the capacity and rate of data transmission for next generation broadband optical communication. It raises a great challenge for current rare‐earth ions doped fiber amplifiers due to the narrow emission bandwidth of rare‐earth ions. In this context, broadband near‐infrared (NIR) emitter based optical amplifiers are in urgent demand. Here, broadband optical amplification in S + C + L bands is achieved for the first time in PbS quantum dot (QD)‐doped low‐melting‐point glass fiber. With the pump of a 976 nm laser, the on‐off gain of PbS QD‐doped fiber (PQDF) ranges from 1.4 to 8.7 dB in 1500–1630 nm, while that of PbS QD‐doped glass ranges from 6.9 to 8.4 dB in 1530–1630 nm. Both QD‐doped glass and optical fiber show tunable luminescence covering the entire optical communication windows (O + E + S + C + L + U). The much higher quantum yield of PbS QDs in glass than that of colloidal QDs, the ultra‐broad and controllable emission bands and bandwidth make PbS QDs doped glass and fiber promising for applications in next generation broadband optical fiber amplifiers and tunable fiber lasers.