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1.
Oncol Lett ; 28(2): 349, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38872862

ABSTRACT

Metadherin (MTDH), initially discovered in primary astrocytes of the human fetus through rapid subtraction hybridization and labeled as astrocyte elevated gene-1, represents a widely recognized oncogene present in multiple types of cancers. However, the role of MTDH in different types of cancer remains unclear. To address this, a comprehensive analysis of MTDH across various types of cancers was conducted by utilizing multiple databases such as The Cancer Genome Atlas. The present analysis discovered that MTDH exhibits differential expression in different types of cancer and is associated with important factors including tumor mutational burden and microsatellite instability. These findings highlighted the significance of MTDH in the tumor microenvironment and its involvement in the development of immune cells in specific cancers. Furthermore, the results of the present study indicated that the expression of MTDH is strongly correlated with clinical prognosis, mutations and immune cell infiltration. MTDH could serve as a potential indicator of patient prognosis and potentially play a role in modulating the immune system. Given its potential as a novel immunological checkpoint, MTDH may be a viable target for tumor immunotherapy.

2.
Oncol Lett ; 27(6): 280, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38699662

ABSTRACT

Breast cancer (BC) is the most common type of cancer found in women. ADP-ribosylation factors (ARFs) are a group of small proteins that bind to GTP and are involved in controlling different cellular functions. The function and evolution of multiple ARFs in BC have remained to be fully elucidated, despite existing studies on this protein family in Homo sapiens and other species. In the present study, a systematic analysis of ARF expression levels in BC tissues compared to normal breast tissues was performed using data from The Cancer Genome Atlas database. The analysis revealed significantly higher expression of ARFs in BC tissues. In addition, the prognostic significance of ARF1 and ARF3-6 expression levels was assessed in patients with BC. Of note, elevated ARF1 expression was associated with reduced rates of distant metastasis-free survival (DMFS), overall survival (OS) and recurrence-free survival (RFS) in affected individuals. Similarly, patients with high expression levels of ARF3 had lower post-progression survival (PPS) rates. In addition, patients with higher ARF4 expression had worse PPS and patients with high ARF5 expression exhibited lower DMFS. Patients with high ARF6 expression had worse DMFS, OS, RFS and predictive power score values. Furthermore, the expression of ARF was found to be strongly linked to the infiltration of various immune cell types, namely dendritic cells, macrophages, neutrophils, CD8+ T cells and B cells. These significant associations offer a solid foundation for the potential utilization of new therapeutic targets and predictive markers for the treatment of BC.

3.
Zhongguo Zhong Yao Za Zhi ; 49(1): 251-267, 2024 Jan.
Article in Chinese | MEDLINE | ID: mdl-38403358

ABSTRACT

This study aims to evaluate the efficacy and safety of Chinese medicine injection in the treatment of acute heart failure. PubMed, Cochrane Library, EMbase, Web of Science, CNKI, VIP, Wanfang, and SinoMed were searched for the randomized controlled trial(RCT) of Chinese medicine injection combined with conventional western medicines in the treatment of acute heart failure with the time interval from the inception to July 10, 2023. Two researchers independently screened the literature, extracted data, and evaluated the risk of bias in the included studies. Stata 15.1 was used to perform network Meta-analysis. A total of 117 RCTs were included, involving 10 529 patients and 7 Chinese medicine injections: Shenfu Injection, Shenmai Injection, Danhong Injection, Puera-rin Injection, Xinmailong Injection, Shengmai Injection, and Yiqi Fumai Injection. Network Meta-analysis yielded the following results.(1) In terms of improving the total response rate, the surface under the cumulative ranking curve(SUCRA) ranking was Shengmai Injection + conventional western medicine > Danhong Injection + conventional western medicine > Shenmai Injection + conventio-nal western medicine > Shenfu Injection + conventional western medicine > Xinmailong Injection + conventional western medicine > Yiqi Fumai Injection + conventional western medicine > Puerarin Injection + conventional western medicine > conventional western medicine.(2)In terms of reducing brain natriuretic peptide(BNP), the SUCRA ranking was Danhong Injection + conventional western medicine > Xinmailong Injection + conventional western medicine > Yiqi Fumai Injection + conventional western medicine > Shenfu Injection + conventional western medicine > Shenmai Injection + conventional western medicine > Puerarin Injection + conventional wes-tern medicine > Shengmai Injection + conventional western medicine > conventional western medicine.(3)In terms of reducing N-terminal pro-brain natriuretic peptide(NT-proBNP), the SUCRA ranking was Shenmai Injection + conventional western medicine > Yiqi Fumai Injection + conventional western medicine > Xinmailong Injection + conventional western medicine > Shengmai Injection + conventional western medicine > Shenfu Injection + conventional western medicine > Puerarin Injection + conventional western medicine > Danhong Injection + conventional western medicine > conventional western medicine.(4) In terms of improving the left ventricular ejection fraction(LVEF), the SUCRA ranking was Shenmai Injection + conventional western medicine > Xinmailong Injection + conventional western medicine > Shenfu Injection + conventional western medicine > Yiqi Fumai Injection + conventional western medicine > Puerarin Injection + conventional western medicine > Danhong Injection + conventional western medicine > Shengmai Injection + conventional western medicine > conventional western medicine.(5) In terms of decreasing the left ventricular end-diastolic diameter(LVEDD), the SUCRA ranking was Shenmai Injection + conventional western medicine > Shenfu Injection + conventional western medicine=Xinmailong Injection + conventional western medicine > Shengmai Injection + conventional western medicine > Yiqi Fumai Injection + conventional western medicine > conventional western medicine > Puerarin Injection + conventional western medicine.(6) In terms of increasing the 6-min walk trail(6MWT), the SUCRA ranking was Xinmailong Injection + conventional western medicine > Shenfu Injection + conventional western medicine > Shenmai Injection + conventional western medicine > Yiqi Fumai Injection + conventional western medicine > conventional western medicine.(7) In terms of reducing the Minnesota heart failure quality of life scale(MLHFQ) scores, the SUCRA ranking was Xinmailong Injection + conventional western medicine > Shenmai Injection + conventional western medicine > Shenfu Injection + conventional western medicine > conventional western medicine.(8)In terms of safety, the group of Chinese medicine injection combined with conventional western medicine had lower incidence of adverse reactions than the control group. The current evidence shows that combining Chinese medicine injection with conventional western medicine treatment can improve the therapeutic effect on acute heart failure, with high safety. Due to the limited number and quality of included studies, the above conclusions need to be verified by more high-quality studies.


Subject(s)
Drugs, Chinese Herbal , Heart Failure , Humans , Drugs, Chinese Herbal/therapeutic use , Heart Failure/drug therapy , Medicine, Chinese Traditional , Natriuretic Peptide, Brain , Network Meta-Analysis , Quality of Life , Stroke Volume , Ventricular Function, Left , Randomized Controlled Trials as Topic
4.
Sci Rep ; 14(1): 1949, 2024 01 23.
Article in English | MEDLINE | ID: mdl-38253625

ABSTRACT

Breast cancer metastasis and invasion are both promoted by the oncoprotein Metadherin (MTDH). However, the the role of Metadherin in breast cancer progression and its role in the immune microenvironment. Are not clear. A bioinformatic analysis was performed to demonstrate the prognostic value of Metadherin in BC. In the present study, we found that Metadherin is overexpressed in BC and is significantly correlated with individual cancer stage, age, subclasses, menopause and nodal metastasis status. Metadherin overexpression was associated with a significant decrease in OS and DSS. Cox multivariate analysis indicated that Metadherin was an independent negative prognostic indicator for OS and DSS. Moreover, Metadherin hypomethylation status was associated with poor prognosis. A negative correlation was also noted between Metadherin overexpression and the number of plasmacytoid dendritic cells, cluster of differentiation 8+ T cells, and natural killer cells. Association patterns varied with different subtypes. Various associations between Metadherin levels and immune cell surface markers were revealed. A total of 40 groups of BC and adjacent normal breast tissue samples were collected. Metadherin mRNA was detected by PCR, and its expression levels in BC tissues were significantly increased compared with those noted in normal tissues. The expression levels of Metadherin were also measured in normal and BC cell lines, respectively, and similar conclusions were obtained. The Metadherin mRNA levels were knocked down in SK-BR3 and MDA-MB-231 cell lines and the cell proliferative and migratory activities were determined using Cell Counting Kit-8 and scratch assays, respectively. The results indicated that the cell proliferative and migratory abilities were reduced following knockdown of Metadherin expression. Therefore, Metadherin may be considered as a novel prognostic biomarker in BC.


Subject(s)
Breast Neoplasms , Female , Humans , Computational Biology , Membrane Proteins/genetics , Neoplasms, Second Primary , Prognosis , RNA, Messenger , RNA-Binding Proteins/genetics , Tumor Microenvironment , Breast Neoplasms/genetics , Breast Neoplasms/immunology , Breast Neoplasms/pathology
5.
Oncol Lett ; 26(1): 312, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37332328

ABSTRACT

The present study aimed to determine the efficacy and safety of pyrotinib in combination with albumin-bound paclitaxel in patients with HER2-positive advanced breast cancer (ABC). A total of 48 patients diagnosed with HER2-positive ABC were included in the present study, and these patients were prescribed a combination of pyrotinib and albumin-bound paclitaxel in routine clinical practice. During a 21-day cycle, the standard dosage of pyrotinib was 400 mg single dose/day, which was administered orally, and 130 mg/m2/day albumin-bound paclitaxel on days 1, 8 and 15, which was administered by intravenous drip. The primary efficacy endpoint was progression-free survival (PFS) and the secondary efficacy endpoint was overall response rate (ORR), which was defined as the percentage of patients with complete remission or partial remission. Safety indicators were also observed in the present study. The results of the present study demonstrated that the median PFS (mPFS) was 8.1 months for all patients, ranging from 3.3-10.6 months. Patients receiving pyrotinib as second-line therapy exhibited a longer mPFS of 8.5 months compared with those receiving it as third- or higher-line therapy (mPFS, 5.9 months). In 17 patients with brain metastases, mPFS was 7.3 months, ranging from 4.8-10.1 months. The results of the present study also demonstrated that the ORR for the 48 patients was 33.3%. Notably, diarrhea was the most common grade 3-4 adverse event, occurring in 22.9% of patients, followed by neutropenia (6.3%), leukopenia (4.2%) and anemia (4.2%). Collectively, the results of the present study indicated that pyrotinib-based treatment is effective for patients with HER2+ ABC, including those who have previously been treated with trastuzumab. Thus, the combination of pyrotinib with albumin-bound paclitaxel is recommended due to high levels of efficacy, convenience and tolerability.

6.
Injury ; 53(12): 3920-3929, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36357245

ABSTRACT

Mesenchymal stem cells (MSCs) play a key role in wound healing, and the advantages of pretreated MSCs in wound healing have previously been reported. In the present study, we investigated the impact of LPS pretreated human adipose-derived MSCs on skin wound healing in diabetic rats. We found that some improvements occurred through improving angiogenesis. Then, we scrutinized the impact of lipopolysaccharide (LPS) treatment on human adipose-derived MSCs in a high-glucose (HG) medium, as an in vitro diabetic model. In vivo findings revealed significant improvements in epithelialization and angiogenesis of diabetic wounds which received LPS pre-MSCs. Particularly, LPS pre-MSCs-treated diabetic wounds reached considerably higher percentages of wound closure. Also, the granulation tissue of these wounds had higher pronounced epithelialization and more vascularization compared with PBS-treated and MSCs-treated diabetic ones by CD31, VEGF, CD90, collagen 1, and collagen 3 immunostaining. Western-blots analyses indicated that LPS pre-MSCs led to the upregulation of vascular endothelial growth factor (VEGF) and DNMT1. In addition, significantly higher cell viability (proliferation/colonie), and elevated VEGF and DNMT1 protein expression were observed when MSCs were treated with LPS (10 ng/ml, 6 h) in HG culture media. Based on these findings, it is suggested that LPS pre-MSCs could promote wound repair and skin regeneration, in some major processes, via the improvement of cellular behaviors of MSCs in the diabetic microenvironment. The beneficial advantages of LPS treated with mesenchymal stem cells on wound healing may lead to establishing a novel approach as an alternative therapeutic procedure to cure chronic wounds in diabetic conditions.


Subject(s)
Diabetes Mellitus, Experimental , Mesenchymal Stem Cells , Rats , Humans , Animals , Lipopolysaccharides/pharmacology , Vascular Endothelial Growth Factor A/metabolism , Diabetes Mellitus, Experimental/therapy , Diabetes Mellitus, Experimental/metabolism , Wound Healing , Collagen/metabolism
7.
Biomed Res Int ; 2022: 2747799, 2022.
Article in English | MEDLINE | ID: mdl-35711526

ABSTRACT

Long noncoding RNAs (lncRNAs) are closely associated with a variety of tumors, including stomach adenocarcinoma (STAD). However, the role of 5-methylcytosine- (m5C-) related lncRNAs in STAD is still uncertain. This study investigated the value of m5C-related lncRNAs in prognostic evaluation and immunotherapy of STAD. STAD transcriptome sequencing data were downloaded from The Cancer Genome Atlas (TCGA) database, and m5C-related lncRNAs were screened by Pearson correlation analysis. A prognostic m5C-related lncRNA signature (m5CRLSig) associated with STAD was established using univariate and multivariate Cox regression analysis. We constructed a prognostic risk model for STAD with six m5C-related lncRNAs. The receiver operating characteristic (ROC) curve was used to examine the predictive efficacy. Univariate and multifactorial Cox regression analysis and principal component analysis (PCA) validated m5CRLSig as an independent factor of STAD prognosis. The clinicopathological characteristics of the model showed higher risk scores for stages II-IV, grade 3, N1-3, and death status. The calibration curve of a nomogram revealed that the nomogram had an excellent predictive function for survival risk. Furthermore, the expression of six m5C-related lncRNAs in STAD and paracancerous tissues was detected by quantitative real-time PCR (qRT-PCR), which verified the feasibility of the m5CRLSig as a prognostic marker for STAD. m5C-related lncRNAs were linked to multiple immune-associated pathways, according to gene set enrichment analysis (GSEA). CIBERSORT analysis indicated that m5CRLSig was involved in immune cell infiltration. Risk score was associated with immune checkpoint gene expression, immune function scores, and chemotherapeutic drug sensitivity. Therefore, m5CRLSig can efficiently assess the prognosis of STAD patients and can be used as a biological marker for immunotherapy.


Subject(s)
Adenocarcinoma , RNA, Long Noncoding , Stomach Neoplasms , Adenocarcinoma/genetics , Adenocarcinoma/metabolism , Adenocarcinoma/therapy , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Gene Expression Regulation, Neoplastic , Humans , Immunotherapy , Prognosis , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Stomach Neoplasms/diagnosis , Stomach Neoplasms/genetics , Stomach Neoplasms/therapy
8.
Biomed Res Int ; 2022: 8607671, 2022.
Article in English | MEDLINE | ID: mdl-35528160

ABSTRACT

Objective: We attempted to evaluate the effects of probiotic-assisted eradication of cytotoxin-associated gene A (cagA)+/vacuolating cytotoxin A (vacA) s1m1 Helicobacter pylori (H. pylori) on the intestinal flora, inflammatory factors, and clinical outcomes. Methods: A total of 180 patients with cagA+/vacA s1m1 H. pylori were randomly divided into two groups. Group A was treated with bismuth quadruple therapy (BQT). Group B was treated with S. boulardii in addition to BQT. The distribution of intestinal flora, serum interleukin-8 (IL-8), IL-17, tumor necrosis factor-α (TNF-α) levels, recovery time of clinical symptoms, total effective rate of clinical symptoms, H. pylori eradication rate, and adverse reactions were observed. Results: 2 weeks after treatment, the contents of Bifidobacterium, Bacteroides, and Lactobacillus in the intestinal tract of Group A decreased, while the amounts of Enterococcus and Enterobacter increased. In Group B, the contents of Bifidobacterium, Bacteroides, and Lactobacillus increased, while the amounts of Enterococcus and Enterobacter did not change significantly. Moreover, the trend of this flora change was still present at 4 weeks after treatment. Compared with Group A, Group B had lower IL-8, IL-17, and TNF-α levels, shorter recovery time of clinical symptoms, higher overall efficiency of clinical symptoms, and lower occurrence of adverse reactions. The eradication rate did not differ significantly between the two groups. Conclusion: BQT can lead to intestinal flora disorders in cagA+/vacA s1m1 H. pylori patients. S. boulardii can improve the distribution of intestinal flora, downregulate immune-inflammatory mediators, and modify clinical symptoms in patients.


Subject(s)
Gastrointestinal Microbiome , Helicobacter Infections , Helicobacter pylori , Probiotics , Antigens, Bacterial/genetics , Bacterial Proteins/genetics , Bismuth/therapeutic use , Cytotoxins , Helicobacter Infections/microbiology , Helicobacter pylori/genetics , Humans , Interleukin-17/therapeutic use , Interleukin-8 , Probiotics/therapeutic use , Tumor Necrosis Factor-alpha
9.
Biomed Res Int ; 2021: 4171019, 2021.
Article in English | MEDLINE | ID: mdl-34888378

ABSTRACT

Studies have shown that COX-2 expression is upregulated in gastric cancer (GC) as well as in precancerous lesions and in Helicobacter pylori-induced inflammation, suggesting that cyclooxygenase-2 (COX-2) may play an important role in gastric carcinogenesis. We attempted to investigate the role of clarithromycin with tinidazole on Helicobacter pylori-related gastritis from the aspects of clinical effect and COX-2 expression. From January 2016 to January 2019, 130 patients with Helicobacter pylori-related chronic gastritis were collected and grouped into the observation group (OG) and the control group (CG). Altogether, 80 patients in the OG were treated with clarithromycin with tinidazole, while 50 patients in the CG were treated with amoxicillin with metronidazole. Clinical symptom improvement time, content of COX-2 and B cell lymphoma-2 (BCL-2), content of inflammatory factors interleukin-1 (IL-1), IL-4, and C-reactive protein (CRP), expression level of nutritional indicators serum albumin (ALB), realbumin (PA), and transferrin (TF), clearance of Helicobacter pylori, total effective rate, and incidence of adverse reactions were detected. Compared with the CG, the OG had shorter clinical symptom improvement time, lower COX-2 and Bcl-2, lower expression of inflammatory factors IL-1, IL-4, and CRP, higher expression of nutritional indicators ALB, TF, and PA, higher clearance rate of Helicobacter pylori, higher total effective rate, and lower incidence of adverse reactions. Clarithromycin combined with tinidazole can effectively improve the clinical effect of Helicobacter pylori-related gastritis and reduce the expression level of COX-2.


Subject(s)
Clarithromycin/therapeutic use , Cyclooxygenase 2/metabolism , Gastritis/drug therapy , Helicobacter Infections/drug therapy , Helicobacter pylori/drug effects , Tinidazole/therapeutic use , Adult , Amoxicillin/therapeutic use , Anti-Bacterial Agents/therapeutic use , Drug Therapy, Combination/methods , Female , Gastritis/metabolism , Gastritis/microbiology , Helicobacter Infections/metabolism , Humans , Male , Metronidazole/therapeutic use , Stomach/metabolism , Stomach/microbiology , Stomach Neoplasms/metabolism , Stomach Neoplasms/microbiology
10.
Opt Lett ; 45(11): 3021, 2020 Jun 01.
Article in English | MEDLINE | ID: mdl-32479448

ABSTRACT

This publisher's note contains corrections to Opt. Lett.45, 2910 (2020).OPLEDP0146-959210.1364/OL.392786.

11.
Opt Lett ; 45(10): 2910-2913, 2020 May 15.
Article in English | MEDLINE | ID: mdl-32412499

ABSTRACT

There has been very little progress in the power scaling of Er/Yb fiber lasers in over a decade, reflecting the difficulties involved. Here we report, to the best of our knowledge, a new record of 302 W single-mode power from an Er/Yb fiber master oscillator power amplifier (MOPA) with a record optical efficiency of 56%, near the quantum limit. This is made possible by new fiber development from Nufern and off-resonant pumping of the Er/Yb fiber. We also show that further power scaling is no longer limited by ytterbium parasitic lasing but by fiber fuse in the Er/Yb fiber.

12.
World J Gastrointest Oncol ; 10(10): 360-366, 2018 Oct 15.
Article in English | MEDLINE | ID: mdl-30364712

ABSTRACT

AIM: To investigate the predictive factors of lymph node metastasis (LNM) in poorly differentiated early gastric cancer (EGC); to guide the individual application of a combination of endoscopic submucosal dissection (ESD) and laparoscopic lymph node dissection (LLND) in a suitable subgroup of patients with poorly differentiated EGC. METHODS: We retrospectively analyzed 138 patients with poorly differentiated EGC who underwent gastrectomy with lymphadenectomy between January 1990 and December 2015. The association between the clinicopathological factors and the presence of LNM was retrospectively analyzed by univariate and multivariate logistic regression analyses. Odds ratios (OR) with 95% confidence interval (95%CI) were calculated. We further examined the relationship between the positive number of the significant predictive factors and the LNM rate. RESULTS: The tumor diameter (OR = 13.438, 95%CI: 1.773-25.673, P = 0.029), lymphatic vessel involvement (LVI) (OR = 38.521, 95%CI: 1.975-68.212, P = 0.015) and depth of invasion (OR = 14.981, 95%CI: 1.617-52.844, P = 0.024) were found to be independent risk factors for LNM by multivariate analysis. For the 138 patients diagnosed with poorly differentiated EGC, 21 (15.2%) had LNM. For patients with one, two and three of the risk factors, the LNM rates were 7.7%, 47.6% and 64.3%, respectively. LNM was not found in 77 patients that did not have one or more of the three risk factors. CONCLUSION: ESD might be sufficient treatment for intramucosal poorly differentiated EGC if the tumor is less than or equal to 2 cm in size and when LVI is absent upon postoperative histological examination. ESD with LLND may lead to the elimination of unnecessary gastrectomy in poorly differentiated EGC.

13.
Opt Express ; 26(3): 3138-3144, 2018 Feb 05.
Article in English | MEDLINE | ID: mdl-29401845

ABSTRACT

Lowering the quantum defect by tandem pumping with fiber lasers at 1018nm was critical for achieving the record 10kW single-mode ytterbium fiber laser. Here we report the demonstration of an efficient directly-diode-pumped single-mode ytterbium fiber laser with 240W at 1018nm. The key for the combination of high efficiency, high power and single-mode at 1018nm is an ytterbium-doped 50µm/400µm all-solid photonic bandgap fiber, which has a practical all-solid design and a pump cladding much larger than those used in previous demonstrations of single-mode 1018nm ytterbium fiber lasers, enabling higher pump powers. Efficient high-power single-mode 1018nm fiber laser is critical for further power scaling of fiber lasers and the all-solid photonic bandgap fiber can potentially be a significant enabling technology.

14.
Opt Express ; 24(10): 10295-301, 2016 May 16.
Article in English | MEDLINE | ID: mdl-27409854

ABSTRACT

Lower NA in large-mode-area fibers enables better single-mode operation and larger core diameters. Fiber NA has traditionally been limited to 0.06, mostly due to the control tolerance in the fabrication process. It has been recognized recently that transverse mode instability is a major limit to average power scaling in fiber lasers. One effective method to mitigate this limit is to operate nearer to the single-mode regime. Lower fiber NA is critical in this since it allows relatively larger core diameters which is the key to mitigate the limits imposed by nonlinear effects. We have developed a fabrication process of ytterbium-doped silica glass which is capable of highly accurate refractive index control and sufficient uniformity for LMA fibers. This process is also capable of large-volume production. It is based on a significant amount of post-processing once the fiber preforms are made. We have demonstrated 30/400 and 40/400 LMA fibers with a NA of ~0.028 operating very close to the single-mode regime. The second-order mode cuts off at ~1.2µm and ~1.55µm respectively. We have also studied issues related to bend losses due to the low NA and further optimization of LMA fibers.

15.
Opt Lett ; 40(10): 2297-300, 2015 May 15.
Article in English | MEDLINE | ID: mdl-26393723

ABSTRACT

An ytterbium-doped large-mode area photonic bandgap fiber is used to demonstrate 400 W of single-frequency output at 1064 nm with excellent beam quality and minimal stimulated Brillouin scattering. The fiber possesses all-solid microstructures embedded in the cladding and a core composed of phosphosilicate with a diameter of ∼50 µm. As the signal power is pushed beyond 450 W, there is degradation in the beam quality due to the modal instability. We briefly discuss techniques to alleviate this problem in future designs. To the best of our knowledge, the 400-W single-frequency near diffraction-limited output far exceeds the current state-of-the-art from such type of fiber amplifier.

16.
Opt Express ; 23(14): 17693-700, 2015 Jul 13.
Article in English | MEDLINE | ID: mdl-26191831

ABSTRACT

Highly-efficient high-power fiber lasers operating at wavelength below 1020 nm are critical for tandem-pumping in >10 kW fiber lasers to provide high pump brightness and low thermal loading. Using an ytterbium-doped-phosphosilicate double-clad leakage-channel fiber with ~50 µm core and ~420 µm cladding, we have achieved ~70% optical-to-optical efficiency at 1018 nm. The much larger cladding than those in previous reports demonstrates the much lower required pump brightness, a key for efficient kW operation. The demonstrated 1018 nm fiber laser has ASE suppression of ~41 dB. This is higher than previous reports and further demonstrates the advantages of the fiber used. Limiting factors to efficiency are also systematically studied.

17.
Opt Express ; 23(7): 9147-56, 2015 Apr 06.
Article in English | MEDLINE | ID: mdl-25968749

ABSTRACT

Mode area scaling of optical fiber is highly desirable for high power fiber laser applications. It is well known that incorporation of additional smaller cores in the cladding can be used to resonantly out-couple higher-order modes from a main core to suppress higher-order-mode propagation in the main core. Using a novel design with multiple coupled smaller cores in the cladding, we have successfully demonstrated a single-mode photonic bandgap fiber with record effective mode area of ~2650µm(2). Detailed numeric studies have been conducted for multiple cladding designs. For the optimal designs, the simulated minimum higher-order-mode losses are well over two orders of magnitudes higher than that of fundamental mode when expressed in dBs. To our knowledge, this is the best higher-order-mode suppression ever found in fibers with this large effective mode areas. We have also experimentally validated one of the designs. M(2)<1.08 across the transmission band was demonstrated.

18.
Opt Express ; 23(4): 4307-12, 2015 Feb 23.
Article in English | MEDLINE | ID: mdl-25836467

ABSTRACT

We demonstrate an Yb-doped polarizing all-solid photonic bandgap fiber for single-polarization and single-mode operation with an effective mode area of ~1150µm(2), a record for all-solid photonic bandgap fibers. The differential polarization mode loss is measured to be >5dB/m over the entire transmission band with a 160nm bandwidth and >15dB/m on the short wavelength edge of the band. A 2.6m long fiber was tested in a laser configuration producing a linearly polarized laser output with a PER value of 21dB without any polarizer, the highest for any fiber lasers based on polarizing fibers.

19.
Opt Express ; 22(12): 14657-65, 2014 Jun 16.
Article in English | MEDLINE | ID: mdl-24977561

ABSTRACT

Quantitative mode characterization of fibers with cores much beyond 50µm is difficult with existing techniques due to the combined effects of smaller intermodal group delays and dispersions. We demonstrate, for the first time, a new method using a matched white-light interferometry (MWI) to cancel fiber dispersion and achieve finer temporal resolution, demonstrating ~20fs temporal resolution in intermodal delays, i.e. 6µm path-length resolution. A 1m-long straight resonantly-enhanced leakage-channel fiber with 100µm core was characterized, showing ~55fs/m relative group delay and a ~29dB mode discrimination between the fundamental and second-order modes.

20.
Opt Express ; 22(11): 13962-8, 2014 Jun 02.
Article in English | MEDLINE | ID: mdl-24921587

ABSTRACT

Single-mode operation in a large-mode-area fiber laser is highly desired for power scaling. We have, for the first time, demonstrated a 50µm-core-diameter Yb-doped all-solid photonic bandgap fiber laser with a mode area over 4 times that of the previous demonstration. 75W output power has been generated with a diffraction-limited beam and an efficiency of 70% relative to the launched pump power. We have also experimentally confirmed that a robust single-mode regime exists near the high frequency edge of the bandgap. These fibers only guide light within the bandgap over a narrow spectral range, which is essential for lasing far from the gain peak and suppression of stimulated Raman scattering. This work demonstrates the strong potential for mode area scaling of in single-mode all-solid photonic bandgap fibers.

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