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1.
Sensors (Basel) ; 24(9)2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38733031

RESUMEN

This study aimed to propose a portable and intelligent rehabilitation evaluation system for digital stroke-patient rehabilitation assessment. Specifically, the study designed and developed a fusion device capable of emitting red, green, and infrared lights simultaneously for photoplethysmography (PPG) acquisition. Leveraging the different penetration depths and tissue reflection characteristics of these light wavelengths, the device can provide richer and more comprehensive physiological information. Furthermore, a Multi-Channel Convolutional Neural Network-Long Short-Term Memory-Attention (MCNN-LSTM-Attention) evaluation model was developed. This model, constructed based on multiple convolutional channels, facilitates the feature extraction and fusion of collected multi-modality data. Additionally, it incorporated an attention mechanism module capable of dynamically adjusting the importance weights of input information, thereby enhancing the accuracy of rehabilitation assessment. To validate the effectiveness of the proposed system, sixteen volunteers were recruited for clinical data collection and validation, comprising eight stroke patients and eight healthy subjects. Experimental results demonstrated the system's promising performance metrics (accuracy: 0.9125, precision: 0.8980, recall: 0.8970, F1 score: 0.8949, and loss function: 0.1261). This rehabilitation evaluation system holds the potential for stroke diagnosis and identification, laying a solid foundation for wearable-based stroke risk assessment and stroke rehabilitation assistance.


Asunto(s)
Redes Neurales de la Computación , Fotopletismografía , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Humanos , Rehabilitación de Accidente Cerebrovascular/instrumentación , Rehabilitación de Accidente Cerebrovascular/métodos , Fotopletismografía/métodos , Fotopletismografía/instrumentación , Accidente Cerebrovascular/fisiopatología , Masculino , Femenino , Persona de Mediana Edad , Adulto , Pletismografía/métodos , Pletismografía/instrumentación , Diseño de Equipo , Dispositivos Electrónicos Vestibles , Algoritmos
2.
Zhongguo Dang Dai Er Ke Za Zhi ; 26(3): 224-229, 2024 Mar 15.
Artículo en Zh | MEDLINE | ID: mdl-38557372

RESUMEN

With an increasing understanding of growth hormone deficiency, there has been a growing emphasis on the management of transition growth hormone deficiency (TGHD) in clinical practice. The inadequate diagnosis and treatment of TGHD have been a major clinical concern, leading to the development of relevant guidelines and consensus internationally. This article summarizes the evaluation, diagnosis, treatment, and clinical challenges of TGHD based on these guidelines, consensus, and existing clinical studies, aiming to optimize and further improve the clinical diagnosis, treatment, and management of TGHD.


Asunto(s)
Enanismo Hipofisario , Hormona de Crecimiento Humana , Humanos , Hormona de Crecimiento Humana/uso terapéutico , Enanismo Hipofisario/diagnóstico , Enanismo Hipofisario/tratamiento farmacológico , Estatura , Consenso
3.
Opt Lett ; 48(24): 6364-6367, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38099749

RESUMEN

We demonstrate an efficient Nd:YVO4/KGW intracavity Raman laser in continuous-wave (CW) scheme. With a V-shaped fundamental laser cavity and a short Stokes cavity in it, the oscillating beam sizes are designed to alleviate the thermal effect and to enhance the Raman gain for efficient CW operation. The output power of CW Stokes wave at 1177 nm reached 9.33 W under an incident laser diode pump power of 36.65 W, with corresponding optical efficiency being 25.5%. To the best of our knowledge, these are the highest Stokes output power and conversion efficiency of CW intracavity Raman lasers.

4.
Opt Lett ; 48(23): 6144-6147, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-38039212

RESUMEN

In this Letter, a watt-level single-frequency fiber oscillator at 2050 nm was demonstrated for the first time, to the best of our knowlegde, in a linear laser cavity with a piece of an un-pumped Tm3+/Ho3+ co-doped fiber serving as a saturable absorber. With delicate optimization of mode filtering effect of the dynamic gratings formed in the saturable absorber, a maximum single-frequency laser output power of 1.2 W was achieved under a total bidirectional pump power of 5.8 W at 1570 nm, and the corresponding optical efficiency is 20.7%. This is, to the best of our knowledge, the highest power of a single-frequency fiber oscillator at the wavelength above 2 µm.

5.
Opt Lett ; 48(23): 6200-6203, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-38039226

RESUMEN

We demonstrate a widely tunable single-frequency Er-doped ZBLAN fiber laser operating on a 4F9/2→4I9/2 transition band. An uncoated germanium (Ge) plate serves as a narrow-bandwidth etalon and is inserted in the cavity to achieve a single longitudinal mode selection. Wavelength tuning from 3373.8 nm to 3718.5 nm was demonstrated by using a blazed diffraction grating at 3.5 µm. At the emission peak of 3465.6 nm, the laser yields over 100 mW single-frequency output power, with a 3 dB linewidth <6.9 MHz, and a slope efficiency (with respect to the incident 1990 nm pump power) of 20.3%. Such a tunable mid-infrared single-frequency fiber laser may serve as a versatile laser source in spectroscopy and sensing applications.

6.
Opt Lett ; 48(3): 598-601, 2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36723540

RESUMEN

A high-power, high-efficiency single-frequency fiber laser at 1064 nm was demonstrated based on a distributed Bragg reflector (DBR) all-silica-fiber configuration. A single-frequency laser with an output power of 642 mW and slope efficiency of 66.4% with respect to absorbed pump power was achieved from a 1.2-cm-long commercially available Yb3+-doped silica fiber. To the best of our knowledge, this is the highest single-frequency laser power and efficiency obtained from the DBR all-silica fiber laser. The work presented here paves the way for the development of high-power, robust, and cost-effective single-frequency Yb3+-doped all-silica fiber lasers.

7.
Sensors (Basel) ; 23(4)2023 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-36850923

RESUMEN

The rapid proliferation of the emerging yet promising notion of the Internet-of-Vehicles (IoV) has led to the development of a variety of conventional trust assessment schemes to tackle insider attackers. The primary reliance of these frameworks is on the accumulation of individual trust attributes. While aggregating these influential parameters, weights are often associated with each individual attribute to reflect its impact on the final trust score. It is of paramount importance that such weights be precise to lead to an accurate trust assessment. Moreover, the value of the minimum acceptable trust threshold employed for the identification of dishonest vehicles needs to be carefully defined to avoid delayed or erroneous detection. This paper employs an IoT data set from CRAWDAD by suitably transforming it into an IoV format. This data set encompasses information regarding 18,226 interactions among 76 nodes, both honest and dishonest. First, the influencing parameters (i.e., packet delivery ratio, familiarity, timeliness and interaction frequency) were computed, and two feature matrices were formed. The first matrix (FM1) takes into account all the pairwise individual parameters as individual features, whereas the second matrix (FM2) considers the average of all pairwise computations performed for each individual parameter as one feature. Subsequently, unsupervised learning is employed to achieve the ground truth prior to applying supervised machine learning algorithms for classification purposes. It is worth noting that Subspace KNN yielded a perfect precision, recall, and the F1-score equal to 1 for individual parametric scores, whereas Subspace Discriminant returned an ideal precision, recall, and the F1-score equal to 1 for mean parametric scores. It is also evident from extensive simulations that FM2 yielded more accurate classification results compared to FM1. Furthermore, decision boundaries among honest and dishonest vehicles have also been computed for respective feature matrices.

8.
Int J Mol Sci ; 24(4)2023 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-36835417

RESUMEN

Tachycines meditationis (Orthoptera: Rhaphidophoridae: Tachycines) is a widely distributed insect in eastern Asia. This species is common in urban environments, and its unique omnivorous diet may contribute to its success in various habitats. However, molecular studies on the species are scarce. Here, we obtained the first transcriptome sequence of T. meditationis and performed preliminary analyses to test whether the evolution of coding sequences fits the expectations based on the species' ecology. We retrieved 476,495 effective transcripts and annotated 46,593 coding sequences (CDS). We analysed the codon usage and found that directional mutation pressure was the leading cause of codon usage bias in this species. This genome-wide relaxed codon usage pattern in T. meditationis is surprising, given the potentially large population size of this species. Moreover, despite the omnivorous diet, the chemosensory genes of this species do not exhibit codon usage deviating significantly from the genome-level pattern. They also do not seem to experience more gene family expansion than other cave cricket species do. A thorough search for rapidly evolved genes using the dN/dS value showed that genes associated with substance synthesis and metabolic pathways, such as retinol metabolism, aminoacyl-tRNA biosynthesis, and fatty acid metabolism, underwent species-specific positive selection. While some results seem to contradict the species ecology, our transcriptome assembly provides a valuable molecular resource for future studies on camel cricket evolution and molecular genetics for feeding ecology in insects, in general.


Asunto(s)
Gryllidae , Animales , Camelus , Transcriptoma , Insectos , Genoma
9.
Int J Mol Sci ; 24(3)2023 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-36768416

RESUMEN

Most butterflies feed on nectar, while some saprophagous butterflies forage on various non-nectar foods. To date, little is known about the genomic and molecular shifts associated with the evolution of the saprophagous feeding strategy. Here, we assembled the high-quality chromosome-level genome of Hestina assimilis to explore its saprophagous molecular and genetic mechanisms. This chromosome-level genome of H. assimilis is 412.82 Mb, with a scaffold N50 of 15.70 Mb. In total, 98.11% of contigs were anchored to 30 chromosomes. Compared with H. assimilis and other Nymphalidae butterflies, the genes of metabolism and detoxification experienced expansions. We annotated 80 cytochrome P450 (CYP) genes in the H. assimilis genome, among which genes belonging to the CYP4 subfamily were significantly expanded (p < 0.01). These P450 genes were unevenly distributed and mainly concentrated on chromosomes 6-9. We identified 33 olfactory receptor (OR), 20 odorant-binding protein (OBP), and six gustatory receptor (GR) genes in the H. assimilis genome, which were fewer than in the nectarivorous Danaus plexippus. A decreased number of OBP, OR, and GR genes implied that H. assimilis should resort less to olfaction and gustation than their nectarivorous counterparts, which need highly specialized olfactory and gustatory functions. Moreover, we found one site under positive selection occurred in residue 996 (phenylalanine) of GR genes exclusive to H. assimilis, which is conservative in most lineages. Our study provides support for the adaptive evolution of feeding habits in butterflies.


Asunto(s)
Mariposas Diurnas , Animales , Mariposas Diurnas/genética , Genoma , Cromosomas/genética , Filogenia
10.
HIV Med ; 23 Suppl 1: 95-105, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35293098

RESUMEN

OBJECTIVES: The emergence of pretreatment drug resistance (PDR) caused by increased usage of antiretroviral therapy (ART) represents a significant challenge to HIV management. In this study, we evaluated the prevalence of PDR in people living with HIV (PLWH) in Chongqing, China. METHODS: We retrospectively collected the data of 1110 ART-naïve PLWH in Chongqing from January 1, 2018 to June 30, 2021. HIV-1 genotypes and drug resistance were analyzed using the HIV-1 pol sequence. Risk factors associated with PDR were evaluated via the logistic regression model. RESULTS: Nine genotypes were detected among 1110 participants, with CRF07_BC (55.68%) being the dominant genotype, followed by CRF01_AE (21.44%), CRF08_BC (14.14%), and other genotypes (8.74%). Of all the participants, 24.14% exhibited drug resistance mutations (DRMs). The predominant DRMs for non-nucleoside reverse transcriptase inhibitors (NNRTIs) and nucleoside reverse transcriptase inhibitors (NRTIs) were V179D/E/A/DIN (13.60%) and M184V/I (1.44%), respectively, whereas only two major DRMs (M46L and I54L) were identified for protease inhibitors (PIs). The total prevalence of PDR was 10.54%, with 2.43%, 7.66%, and 1.71% participants exhibiting PDR to NRTIs, NNRTIs, and PIs, respectively. Furthermore, female PLWH, delays in ART initiation, and the CRF08_BC genotype were associated with a higher risk of PDR. CONCLUSIONS: Our study provides the first large cohort data on the prevalence of PDR in Chongqing, China. HIV-1 genotypes are diverse and complex, with a moderate level of PDR, which does not reach the threshold for the initiation of a public health response. Nevertheless, continuous surveillance of PDR is both useful and advisable.


Asunto(s)
Fármacos Anti-VIH , Infecciones por VIH , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/uso terapéutico , China/epidemiología , Farmacorresistencia Viral/genética , Femenino , Genotipo , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , Humanos , Mutación , Prevalencia , Estudios Retrospectivos , Inhibidores de la Transcriptasa Inversa/farmacología
11.
Opt Express ; 30(9): 15575-15582, 2022 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-35473274

RESUMEN

We report a single-frequency pulsed Yb-doped fiber master-oscillator-power-amplifier at 1064 nm producing output with pulse energy of 0.6 mJ for a pulse width of 95 ns at a pulse repetition frequency of 5 kHz. Integral to this laser design was the application of a hybrid active-fiber, which integrated a length of heavily Yb-doped phosphosilicate fiber (with a core diameter of 50 µm) with a silica gain fiber (with core diameter of 35 µm). This was used in the power amplifier stage to both suppress stimulated Brillouin scattering and to enhance the gain saturation for improved efficiency and spectral signal to noise ratio. The seed pulses were pre-shaped so that sawtooth-like pulses were obtained after amplification, this having the effect of preventing linewidth broadening induced by self-phase modulation. A spectral linewidth of ∼15 MHz was measured at the maximum peak power of 6.3 kW.

12.
Opt Lett ; 47(15): 3684-3687, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35913289

RESUMEN

In this paper, a novel, to the best of our knowledge, efficient pump scheme for an erbium-doped fluoride fiber laser with emission at 2.8 µm in the mid-infrared region is proposed and demonstrated. A singular pump source at 1.7 µm is used to excite Er3+ ions from ground state 4I15/2 to lower laser level 4I13/2, and then further boost the ions to 4I9/2, where a non-radiation transition occurs for the Er3+ ions to reach upper laser level 4I11/2. This scheme can efficiently recycle ions on the lower laser level 4I13/2 by excited-state absorption, therefore realizing population inversion and enhancing laser efficiency. In our demonstration, a 660-mW laser output at 2.8 µm is achieved from a 1.7-µm core-pumped erbium-doped fluoride fiber laser, where the slope efficiency versus launched pump power is 23.7%. The proposed innovative pump scheme shows great potential to realize high-power, high-efficiency erbium-doped fiber lasers at 2.8 µm.

13.
Opt Lett ; 47(15): 3964-3967, 2022 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-35913359

RESUMEN

We demonstrate an efficient single-frequency Tm-doped fiber laser at 2050 nm. A ring cavity scheme is employed to boost the net gain at the wavelength. A piece of Tm/Ho-codoped fiber with an absorption coefficient at 2050 nm higher than that of a Tm-doped fiber is used to establish the dynamic Bragg grating for enhancing the frequency selection capability. A single-frequency output of 215 mW is obtained under 2 W of 1570-nm pump power, with the slope efficiency being 22%. To the best of our knowledge, this is the highest single-frequency all-fiber laser oscillator output power above 2 µm.

14.
Environ Res ; 212(Pt B): 113292, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35427596

RESUMEN

Silver nanoparticles (AgNPs) are considered as emerging contaminants because of their high toxicity and increasing environmental impact. Removal of discharged AgNPs from water is crucial for mitigating the health and environmental risks. However, developing facile, economical, and environment-friendly approaches remains challenging. Herein, an Fe3O4-Mg(OH)2 nanocomposite, as a novel magnetic scavenger for AgNPs, was prepared by loading Fe3O4 nanoparticles on Mg(OH)2 nanoplates in a one-pot synthesis. Batch removal experiments revealed that the maximum removal capacities for the two model AgNPs (citrate- or polyvinylpyrrolidone-coated AgNPs) were 476 and 442 mg/g, respectively, corresponding to partition coefficients 8.03 and 4.89 mg/g/µM. Removal feasibilities over a wide pH range of 5-11 and in real water matrices and scavenger reusability with five cycles were also confirmed. Both Fe3O4 and Mg(OH)2 components contributed to the removal; however, their nanocomposites exhibited an enhanced performance because of the high specific surface area and pore volume. Chemical adsorption and electrostatic attraction between the coatings on the AgNPs and the two components in the nanocomposite was considered to be responsible for the removal. Overall, the facile synthesis, convenient magnetic separation, and high removal performance highlight the great potential of the Fe3O4-Mg(OH)2 nanocomposite for practical applications.


Asunto(s)
Nanopartículas del Metal , Nanocompuestos , Adsorción , Plata , Agua
15.
BMC Pediatr ; 22(1): 486, 2022 08 13.
Artículo en Inglés | MEDLINE | ID: mdl-35964110

RESUMEN

BACKGROUND: Coffin-Siris syndrome (CSS) is a rare autosomal dominant disorder characterized by intellectual disability, developmental delay, and characteristic facial features. Few patients with cutaneous phenotype in this rare syndrome have been reported. CASE PRESENTATION: Herein, we describe a 12-year-old Chinese girl diagnosed with CSS, who was referred to our hospital because of intellectual disability and short stature. Prominent characteristics of the cutaneous system were observed: (1) A congenital giant nevus from the left frontal and temporal regions to the entire left scalp; and (2) multiple melanocytic nevi on the face and trunk. Whole exome sequencing revealed a novel heterozygous variant in the ARID1B gene. Recombinant human growth hormone (rhGH) was given for short stature, and resulted in significantly improved height. No enlargement or malignant transformation of nevi occurred within 4 years of follow-up. CONCLUSION: The symptoms in cutaneous system is noteworthy,which may be a neglected phenotype in CSS.The therapeutic response of growth hormone is effective in this patient and no tumor related signs were found.


Asunto(s)
Enanismo , Deformidades Congénitas de la Mano , Micrognatismo , Nevo Pigmentado , Anomalías Múltiples , Niño , Proteínas de Unión al ADN/genética , Enanismo/genética , Cara/anomalías , Femenino , Deformidades Congénitas de la Mano/diagnóstico , Deformidades Congénitas de la Mano/genética , Humanos , Discapacidad Intelectual , Micrognatismo/genética , Cuello/anomalías , Nevo Pigmentado/genética , Factores de Transcripción/genética
16.
Int J Mol Sci ; 23(20)2022 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-36292953

RESUMEN

Gene arrangement (relative location of genes) is another evolutionary marker of the mitogenome that can provide extensive information on the evolutionary mechanism. To explore the evolution of gene arrangements in the mitogenome of diversified Ensifera, we sequenced the mitogenome of the unique dune cricket species found in China and used it for phylogenetic analysis, in combination with 84 known Ensiferan mitogenomes. The mitogenome of Schizodactylus jimo is a 16,428-bp circular molecule that contains 37 genes. We identified eight types of gene arrangement in the 85 ensiferan mitogenomes. The gene location changes (i.e., gene translocation and duplication) were in three gene blocks: I-Q-M-ND2, rrnl-rns-V, and ND3-A-R-N-S-E-F. From the phylogenetic tree, we found that Schizodactylus jimo and most other species share a typical and ancient gene arrangement type (Type I), while Grylloidea has two types (Types II and III), and the other five types are rare and scattered in the phylogenetic tree. We deduced that the tandem replication-random loss model is the evolutionary mechanism of gene arrangements in Ensifera. Selection pressure analysis revealed that purifying selection dominated the evolution of the ensiferan mitochondrial genome. This study suggests that most gene rearrangements in the ensiferan mitogenome are rare accidental events.


Asunto(s)
Genoma Mitocondrial , Ortópteros , Animales , Orden Génico , Genoma Mitocondrial/genética , Ortópteros/genética , Filogenia , Reordenamiento Génico , Aves
17.
Zhongguo Dang Dai Er Ke Za Zhi ; 24(4): 405-410, 2022 Apr 15.
Artículo en Zh | MEDLINE | ID: mdl-35527416

RESUMEN

OBJECTIVES: To study the clinical features and fibroblast growth factor receptor 3 (FGFR3) gene mutations of children with achondroplasia (ACH) through an analysis of 17 cases. METHODS: A retrospective analysis was performed on the clinical data and FGFR3 gene detection results of 17 children with ACH who were diagnosed from January 2009 to October 2021. RESULTS: Of the 17 children with ACH, common clinical manifestations included disproportionate short stature (100%, 17/17), macrocephaly (100%, 17/17), trident hand (82%, 14/17), and genu varum (88%, 15/17). The common imaging findings were rhizomelic shortening of the long bones (100%, 17/17) and narrowing of the lumbar intervertebral space (88%, 15/17). Major complications included skeletal dysplasia (100%, 17/17), middle ear dysfunction (82%, 14/17), motor/language developmental delay (88%, 15/17), chronic pain (59%, 10/17), sleep apnea (53%, 9/17), obesity (41%, 7/17), foramen magnum stenosis (35%, 6/17), and hydrocephalus (24%, 4/17). All 17 children (100%) had FGFR3 mutations, among whom 13 had c.1138G>A hotspot mutations of the FGFR3 gene, 2 had c.1138G>C mutations of the FGFR3 gene, and 2 had unreported mutations, with c.1252C>T mutations of the FGFR3 gene in one child and c.445+2_445+5delTAGG mutations of the FGFR3 gene in the other child. CONCLUSIONS: This study identifies the unreported mutation sites of the FGFR3 gene, which extends the gene mutation spectrum of ACH. ACH is a progressive disease requiring lifelong management through multidisciplinary collaboration.


Asunto(s)
Acondroplasia , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos , Acondroplasia/diagnóstico , Acondroplasia/genética , Niño , Humanos , Mutación , Osteocondrodisplasias/genética , Receptor Tipo 3 de Factor de Crecimiento de Fibroblastos/genética , Estudios Retrospectivos
18.
Opt Express ; 29(17): 27048-27056, 2021 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-34615127

RESUMEN

Here we demonstrated an efficient high-power single-frequency thulium-doped fiber ring laser operating at 1720 nm. Three cascaded sub-rings were inserted into the main cavity to significantly enlarge the effective free spectral range. By incorporating a fiber Bragg grating, the single longitudinal mode operation was achieved. The maximum single-frequency output power reached up to 1.11 W under 3.75-W launched pump power, while the slope efficiency with respect to the absorbed pump power was 46.4%. The laser linewidth at maximum single-frequency power was measured of 1.9 kHz. Potential power scaling of the single-frequency output power with different quantity and lengths of the sub-rings was also theoretically investigated.

19.
Opt Express ; 29(21): 34269-34277, 2021 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-34809221

RESUMEN

Here we demonstrate an efficient, long-distributed-cavity laser which uses a cat-eye retroreflector configuration to facilitate cavity alignment. The cavity parameters were optimized to meet the small stability region of the cavity, given the long working distance. We also found that intracavity spherical aberration seriously impacts laser efficiency, and an aspheric lens is used to correct the aberration when long working distance and receivers with compact dimensions are desired. The end-pumped Nd:YVO4 laser delivered 5.91 W continuous-wave output power at a long working distance of 5 m, under 16.6 W incident diode pump. Significantly, the fluctuation in output power over the whole working distance range of 1-5 m was less than 10%, this being achieved without any other cavity parameters being adjusted.

20.
Opt Express ; 29(16): 25280-25289, 2021 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-34614861

RESUMEN

In this paper, we demonstrate an efficient 1.7-µm Tm-doped fiber laser whose cavity was embedded in a 1560 nm erbium/ytterbium-codoped fiber laser cavity, which enabled bidirectional pumping and made full use of the circulating pump in the parent laser cavity. A rate equation model was developed to optimize the fiber length and output coupling for a desired output power. In the experiment, a maximum output power at 1720 nm of 1.13 W was obtained under 10 W of 976 nm diode pump power, which correlated well with our modeling. The slope efficiency from the multimode 976 nm diode pump to 1720 nm output was 13.5%, while the slope efficiency in terms of launched 1560 nm pump power reached 62.5%. By using a short Tm-doped fiber to minimize signal reabsorption, a high signal-to-noise ratio over 65 dB was achieved. The prospect for further power scaling was also discussed based on our developed model.

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