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S/S+band에서 넓은 파장가변 영역을 가지고 50-GHz ITU-T격자에 맞는 채널을 생성하는 thulium이 첨가된 광섬유 레이저
안성준,박철근,안승준,박종한,박남규 한국광학회 2004 한국광학회지 Vol.15 No.1
S/S+band에서 ITU-T의 50 ㎓격자에 맞는 채널을 가지는 광대역 파장가변 thulium첨가 광섬유레이저(TTDFL)를 개발하였다. 1.4$\mu\textrm{m}$및 $1.5\mu\textrm{m}$두 대역의 광원으로 펌핑되는 thulium첨가 광섬유(TDF)의 반전에 관한 분석을 통해, 대부분의 S/S+band에서 파장을 가변할 수 있는 레이저를 구현하였다. 이 파장가변 레이저는 65.1nm의 넓은 3-㏈ 대역폭 내에서 6.7㏈m이상의 평탄한 출력 스펙트럼을 보여주었고, 생성된 DWDM채널 수는 178개에 달하였다. 또한 보조 펌프의 출력을 더 높일경우 66.2 nm까지도 대역폭을 넓힐 수 있었고, 공진기 내부 필터의 온도를 조절함으로써 레이저의 주파수를 더욱 안정화 할 수 있음도 보였다. 본 연구에서 개발된 이 레이저는 S/S+band에서 기준 파장을 제공하는 유용한 광원으로 활용될 수 있다. We demonstrate an S/S+band discretely tunable thulium doped fiber laser (TTDFL), anchored on a 50-㎓ ITU-T grid. Investigating the inversion analysis of the thulium doped fiber (TDF) in applying a dual wavelength (1.4 m and 1.5 m) pumping scheme, a laser whose tuning range covers most of the S/S+band has been obtained. Within the wide 3-㏈ bandwidth of 65.1 nm, the output power of the tunable laser exceeds 6.1 ㏈m with very flat spectral profile and the number of DWDM channels generated is as large as 178. If we increase the subsidiary pump power to 22 ㎽, the bandwidth is expanded up to 66.2 nm. By controlling the temperature of the fine grid filter, we have also shown that the frequency locking capability of the laser can be improved. The laser developed in this work is expected to be utilized as a practical optical source providing reference wavelengths in the S/S+band.
정재승,서원익,오철규,김성철,박명찬,박상현,유지형,이찬호,김완석,박태용,민권식,정재일 대한비뇨의학회 2020 Investigative and Clinical Urology Vol.61 No.1
Purpose: Preoperative use of 5α-reductase inhibitors (5ARIs) may cause fibrosis of the prostate tissue and reduce the efficiency of thulium laser surgery for treating benign prostate hyperplasia (BPH). Thus, we investigated the effects of preoperative 5ARI use in this setting. Materials and Methods: This retrospective study examined 184 patients who underwent thulium laser surgery for BPH during 2012–2017. Patients were grouped according to their 5ARI use in order to compare their preoperative and intraoperative characteristics and subsequent outcomes. Surgical efficiency was assessed using vaporesection efficiency. The total operation time, vaporesection time and prostate volume change were measured. Results: The 5ARI+ group included 83 patients (45.1%) and the 5ARI− group included 101 patients (54.9%). There were no significant differences in the two groups' preoperative characteristics, postoperative prostate size, thulium laser energy use, or prostate volume reduction rate. However, relative to the 5ARI− group, the 5ARI+ group had a significant shorter total operative time (65.0 min vs. 70.0 min, p=0.013) and a significantly shorter vaporesection time (48.0 min vs. 54.0 min, p=0.014), which resulted in significantly higher vaporesection efficiency in the 5ARI+ group (0.66 mL/min vs. 0.51 mL/min, p<0.001). Both groups exhibit significant improvements in their quality of life score and International Prostate Symptom Score during the 12-month follow-up. Conclusions: In contrast with our expectations, the preoperative use of 5ARI increased the efficiency of thulium laser surgery for BPH. Thus, it may not be necessary to stop 5ARI treatment before performing thulium laser surgery in this setting.
THULIUM:ZBLAN BLUE 상방전환 광섬유 레이저 모델링
조성진,김용평 慶熙大學校 레이저 工學硏究所 2002 레이저공학 Vol.13 No.-
A theory is presented for thulium-doped ZBLAN fiber amplifiers and lasers that are upconversion pumped by a single source at 1140 nm and emit in the blue spectrum at 480 nm. This computer model describes the performance of such lasers with good accuracy despite the complicated three-step upconversion mechanisms and are able to specify the corresponding spectroscopic parameters. We discuss the relevance of these processes to the 480 nm laser performance. The laser model is compared with published experimental data.
200-W Continuous-wave Thulium-doped All-fiber Laser at 2050 nm
신재성,차용호,천병재,정도영,박현민 한국광학회 2021 Current Optics and Photonics Vol.5 No.3
A 200-W continuous-wave thulium-doped all-fiber laser at 2050 nm was developed with a master oscillator power amplifier configuration. For the master oscillator, a single-mode thulium-doped fiber laser was built with fiber Bragg gratings. The operating power of the oscillator was 10.1 W at a pump power of 20.9 W, and the slope efficiency was measured to be 53.0%. All emitted wavelengths of the oscillator were located between 2049.2 nm and 2049.9 nm, and no other peaks in different wavelength ranges were observed. The maximum output power of the final amplified beam was 204.6 W at a pump power of 350.4 W. The slope efficiency of the amplifier was measured to be 58.4%.
Ben H. Chew,구교철,Abdulghafour Halawani,Colin J. Lundeen,Bodo E. Knudsen,Wilson R. Molina 대한비뇨의학회 2023 Investigative and Clinical Urology Vol.64 No.3
Purpose: Holmium:YAG laser lithotripsy requires high amperage power and has an upper limit of frequency and a minimal fiber size. The technology utilizing thulium-doped fiber offers low pulse energy settings and high pulse frequencies up to 2,400 Hz. We compared the novel SuperPulsed thulium fiber laser (SOLTIVE™; Olympus) to a commercially available 120 W Ho:YAG laser. Materials and Methods: Bench-top testing was conducted with 125 mm3 standardized BegoStones (Bego USA). Time to ablate the stone into particles <1 mm was recorded for efficiency calculations. Finite energy was delivered, and resulting particle sizes were measured to determine fragmentation (0.5 kJ) and dusting (2 kJ) efficiencies. Remaining mass or number of fragments were measured to compare efficacy. Results: SOLTIVE™ was faster at ablating stones to particles <1 mm (2.23±0.22 mg/s, 0.6 J 30 Hz short pulse) compared to Ho:YAG laser (1.78±0.44 mg/s, 0.8 J 10 Hz short pulse) (p<0.001). Following 0.5 kJ of energy in fragmentation testing, fewer particles >2 mm remained using SOLTIVE™ than Ho:YAG laser (2.10 vs. 7.20 fragments). After delivering 2 kJ, dusting (1.05±0.08 mg/s) was faster using SOLTIVE™ (0.1 J 200 Hz short pulse) than 120 W 0.46±0.09 mg/s (0.3 J 70 Hz Moses) (p=0.005). SOLTIVE™ (0.1 J 200 Hz) produced more dust particles <0.5 mm (40%) compared to 24% produced by the P120 W laser at 0.3 J 70 Hz Moses and 14% at 0.3 J 70 Hz long pulse (p=0.015). Conclusions: The efficacy of SOLTIVE™ is superior to the 120 W Ho:YAG laser by producing smaller dust particles and fewer fragments. Further studies are warranted.
김준우,김연주,이윤형,권준범,조성룡,김재수 대한비뇨의학회 2014 Investigative and Clinical Urology Vol.55 No.1
Purpose: In recent years, laser surgery has been widely used to treat benign prostatic hyperplasia (BPH). A thulium:yttrium-aluminium-garnet (Tm:YAG) laser was recently introduced for BPH surgery. We compared the effectiveness and safety of Tm:YAG laser vaporesection of the prostate (ThuVaRP) with that of bipolar transurethral resection of the prostate (TURP). Materials and Methods: From January 2010 to December 2012, 86 patients underwent surgical treatment for symptomatic BPH by a single surgeon. We retrospectively analyzed and compared the medical records of 43 patients who underwent ThuVaRP and 43 patients who underwent bipolar TURP. All patients were assessed by using the International Prostate Symptom Score, transrectal ultrasonography, the serum prostate- specific antigen (PSA) level, uroflowmetry, and postvoid residual volume before and 1 month after surgery. All complications were compared between the two groups. Results: ThuVaRP was superior to TURP in catheterization time (p<0.001) and length of hospital stay (p<0.001). However, operation time was longer with ThuVaRP than with TURP (p<0.001). In patients with a large prostate (>50 g), operation time was much longer with ThuVaRP. One month after surgery, the decrease in PSA was greater (p=0.045) with ThuVaRP than with TURP, and the increase in maximal urine flow rate was greater (p<0.001) with ThuVaRP than with TURP. The postoperative complication transient urinary incontinence was significantly different between the ThuVaRP group (nine cases, 20.9%) and the TURP group (two cases, 4.7%). Other complications were comparable between groups. Conclusions: The effectiveness and safety of ThuVaRP and TURP were comparable. ThuVaRP is a promising alternative surgical technique to TURP for BPH.
40-W 200-ns 300-kHz Thulium-doped Fiber Laser at 2050 nm
신재성,차용호,천병재,박현민 한국광학회 2021 Current Optics and Photonics Vol.5 No.5
A 40-W 200-ns 300-kHz thulium-doped fiber laser at 2050 nm with a master oscillator power amplifier configuration was developed, for application to lithium-isotope separation. The master oscillator generated a 5.35 W continuous-wave beam, which the pulse generator then broke into 200-ns pulses at 300 kHz. Then, the laser beam was amplified by passing through a two-stage amplifier. The output power finally obtained was 42.0 W at 2050 nm, and was stable for a long time, over 2 hours. In spite of this achievement, mode instability was observed in the output beam. This can be solved in the future by using a method such as tight coiling.