Heat dissipation in high-power semiconductor lasers with heat pipe cooling system

Shili Shu,Guanyu Hou,Lijie Wang,Sicong Tian,Leonid L. Vassiliev,Cunzhu Tong 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6

This study focuses on the application of heat pipes in thermal management for high-power semiconductor lasers. The heat pipe cooling systems are used for heat dissipation in high-power semiconductor lasers. These systems are used instead of water cooling machines to realize a compact and lightweight laser module. The n-shaped heat pipe cooling system, which consists of eight 6 mm copper heat pipes with sintered powder wicks, can easily handle a heat load of up to 73 W from a single-laser unit. The fabricated U-shaped heat pipe cooling system, which consists of ten 12 mm copper heat pipes with sintered powder wicks, can easily handle a heat load of up to 300 W from five laser units. The optical power of the multi-laser module cooled by the U-shaped heat pipe cooling system reaches 210 W. These results indicate that high-power semiconductor lasers can be cooled using heat pipe cooling systems instead of water cooling machines.

반도체 패키징용 에폭시 기반 접합 소재 및 공정 기술 동향

엄용성,최광성,최광문,장기석,주지호,이찬미,문석환,문종태,Eom, Y.S.,Choi, K.S.,Choi, G.M.,Jang, K.S.,Joo, J.H.,Lee, C.M.,Moon, S.H.,Moon, J.T. 한국전자통신연구원 2020 전자통신동향분석 Vol.35 No.4

Since the 1960s, semiconductor packaging technology has developed into electrical joining techniques using lead frames or C4 bumps using tin-lead solder compositions based on traditional reflow processes. To meet the demands of a highly integrated semiconductor device, high reliability, high productivity, and an eco-friendly simplified process, packaging technology was required to use new materials and processes such as lead-free solder, epoxy-based non cleaning interconnection material, and laser based high-speed processes. For next generation semiconductor packaging, the study status of two epoxy-based interconnection materials such as fluxing and hybrid underfills along with a laser-assisted bonding process were introduced for fine pitch semiconductor applications. The fluxing underfill is a solvent-free and non-washing epoxy-based material, which combines the underfill role and fluxing function of the Surface Mounting Technology (SMT) process. The hybrid underfill is a mixture of the above fluxing underfill and lead-free solder powder. For low-heat-resistant substrate applications such as polyethylene terephthalate (PET) and high productivity, laser-assisted bonding technology is introduced with two epoxy-based underfill materials. Fluxing and hybrid underfills as next-generation semiconductor packaging materials along with laser-assisted bonding as a new process are expected to play an active role in next-generation large displays and Augmented Reality (AR) and Virtual Reality (VR) markets.

Enhancement of the Phase-modulation Range by Using Cascaded Injection-locked Semiconductor Lasers

Hwan Lee,Jun-Hyung Cho,Hyuk-Kee Sung 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.6

The phase modulation of an injection-locked semiconductor laser can be controlled by tuning the injection-locking parameters. However, the phase-modulation range is limited to 180, which significantly hinders its widespread application. In this study, we investigated the phase-modulation characteristics of a single stage of an injection-locked laser configuration by considering a slave laser’s bias control as a tuning parameter. Herein, we propose cascaded injection-locked laser configurations to enhance the phase-modulation range and theoretically demonstrate that the achievable phasemodulation range can be increased. The output of the slave laser is used as the input of the next slave laser to produce an accumulated phase modulation. The results show that a phase modulation of 360 can be achieved using the cascaded configurations; moreover, the number of cascaded configurations required to achieve this range is determined for specific laser parameters.

광펌핑된 루비듐 원자의 원형 편광 분광

박종대,권병국 培材大學校 1997 培材論叢 Vol.2 No.-

반도체 레이저의 주파수를 절대적으로 안정화시키기 위하여 루비듐 원자의 흡수선을 이용하였다. 이를 위해 두 개의 서로 수직인 편광자 안에 류비듐 셀을 설치하고, 광펌핑으로 루비듐 원자에 원형 복굴절을 유도하였다. 반도체 레이저에서 나온 레이저 빔이 이 셀을 통과하여 되먹임 되도록하여 광학적으로 반도체 레이저의 주파수를 안정화 시켰다. Absorption spectrum of Rubidium atoms was utilized to stabilize the oscillation frequency of a semiconductor laser. A Rubidium cell was installed between crossed polarizers and circular birefringence was induced by optical pumping. The frequency of a semiconductor laser was stabilized by optical feedback of transmitted laser beam through the optically pumped cell.

Outcome of 980 nm diode laser vaporization for benign prostatic hyperplasia: A prospective study

M. Hammad Mithani,Salman El Khalid,Shariq Anis Khan,Imran Sharif,Adnan Siddiq Awan,Shoaib Mithani,Irfan Majeed 대한비뇨의학회 2018 Investigative and Clinical Urology Vol.59 No.6

Purpose: To evaluate the initial experience and outcome of photo-selective vaporization of the prostate (PVP) for benign prostatic hyperplasia (BPH) in Pakistan with the use of a 980 nm diode laser. Materials and Methods: A prospective study was performed from November 2016 to December 2017. A total of 100 patients diagnosed with bladder outlet obstruction secondary to BPH who planned for PVP were enrolled in the study. PVP was carried out with a diode laser at 980 nm (Biolitec Diode 180W laser) in a continuous wave with a 600 nm (twister) fiber. Baseline characteristics and perioperative data were compared. Postoperative outcomes were evaluated by International Prostate Symptom Score (IPSS), post void residual (PVR) and maximum urinary flow rate (Qmax) at 3 and 6 months after surgery. Results: The mean age was 65.82±10.42, mean prostate size was 67.35±16.42, operative time was 55.85±18.01 and total energy was 198.68±49.12 kJ. At 3 months and 6 months, significant improvements were noted (p<0.001) in IPSS 7.04±1.69 (−18.92), Qmax 19.22±4.75 mL/s (+13.09) and and PVR 18.89±5.39 mL (−112.80). Most frequent problems were burning micturition (35%) and terminal dysuria (29%). No significant difference in postoperative hemoglobin was seen in patients who were on anti-platelet drugs. Conclusions: PVP with a diode laser is a safe and effective procedure for the treatment of BPH and is also safe in patients who are on anti-platelet agents.

Theoretical Analysis of an Optoelectronic Oscillator Based on a Directly Modulated Semiconductor Laser

Jun-Hyung Cho,Seo Weon Heo,Hyuk-Kee Sung 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.9

We numerically simulated the performance of an optoelectronic oscillator (OEO) based on a directly modulated (DM) semiconductor laser. The standard coupled rate equations were used to describe the DM-OEO modulation process. A rate-equation-based analysis is a means of analyzing OEO performance that is a variation of the method used to assess standard OEOs that employ external modulators. We modeled an OEO with an open-loop response and calculated the oscillation threshold gain and amplitude of the DM-OEO as functions of the DC bias current. By using this method, we were able to optimize OEO operation conditions for a given laser DC bias level in both gain- and amplitude-limited operating environments.

2차원의 규칙적인 비주기 레이저

노희소 한국물리학회 2013 새물리 Vol.63 No.9

We demonstrated lasing in localized optical modes of deterministic aperiodic lasers. The laser is realized by pattering an aperiodic structure on a GaAs membrane. The optical properties of the lasing modes are similar to those from random structures. However, the lasing modes from aperiodic structures are reproducible due to the reproducibility of the structures. Also, by gradually changing the structural aperiodicity, we study the effect of aperiodicity. We find an optimal degree of aperiodicity where lasing is the strongest. 우리는 규칙적인 비주기 구조로부터 국소화된 모드를 가진 레이저를제작하였다. 이러한 레이저는 GaAs 박막에 패턴을 제작함으로써구현되었다. 제작된 레이저의 광학적 특성은 랜덤구조로 부터 발현되는랜덤레이저와 비슷한 특성을 보이지만 랜덤레이저와는 달리 비주기구조는 재현 가능하므로 이로부터 나오는 레이저 또한 재현가능한 특징을보인다. 또한 비주기 구조 레이저 패턴의 비주기 정도를 변화시켜가면서레이징 현상의 변화를 연구하였다. 이로부터 레이저는 완전한 주기구조와완전한 비주기 구조 중간의 한 특정한 값에서 가장 높은 퀄리티 값을가지는 것을 실험과 전산모를 통하여 확인하였다.

Analyses of Spectral Behaviors of Semiconductor Lasers under Weak Optical Injection Locked to External Light Injected

Kim, Jung-Tae The Korea Institute of Information and Commucation 2009 Journal of information and communication convergen Vol.7 No.4

We have investigated the spectral characteristics of semiconductor lasers locked to the external light injected from a modulated laser. study on FM sideband injection locking has shown that when SLs are locked to the target sidebands of the directly modulated ML, the presence of the unselected sidebands influences the resulting microwave signals. The unselected signals can produce the unwanted beat signals around the desired beat signal, which degrade the overall system performance. This analysis way to generate Giga HZ signal generation.

Laser-induced diamagnetic anisotropy of coaxial nanowires

E.C. Niculescu,A. Radu 한국물리학회 2010 Current Applied Physics Vol.10 No.5

The diamagnetic susceptibility of the hydrogenic impurity in coaxial quantum well wires under high frequency laser field has been investigated taking into account the laser dressing effect on both the impurity Coulomb potential and confinement potential. The analysis revealed that a laser beam which is linearly polarized along the wire radial direction destroys the cylindrical symmetry of the donor Hamiltonian, leading to a strong dependence of the electron probability density on the laser field amplitude and orientation of the applied magnetic field. Thus, the direction of the magnetic field can be used as a tunable parameter in the variation of the diamagnetic susceptibility in low-dimensional structures under intense laser radiation. This phenomenon gives an additional degree of freedom in device applications.

Non-contact tactile stimulation based on plasma using high-power laser diode

( Ki-hyeon Park ),( Jinsu An ),( Kyu-beom Kim ),( Soon-cheol Chung ),( Hyung-sik Kim ) 한국감성과학회 2023 한국감성과학회 국제학술대회(ICES) Vol.2023 No.-

In this study, we discovered the conditions of laser-induced plasma generation using 1-Watt pulsed semiconductor laser. To generate a laser-induced plasma, we focused the pulsed laser using the F-theta lens of 100 mm and 250 mm focal length. By adjusting the Repetition Rate, Diode Current and Pulse Width of the pulsed laser, we observed different appearances of the laser-induced plasma; Spatial Plasma, Contact Plasma and discovered the corresponding plasma generation range. Spatial Plasma is a visible midair plasma without any obstruction. Contact Plasma is a plasma only visible when an object contacts the focused spot. In both F-Theta lens conditions, Repetition Rate 5 Hz Spatial Plasma and Contact Plasma had the largest plasma generation range and the range narrows as the Repetition Rate increases. At 250 mm focal length condition, we only observed Contact Plasma. We discovered a much higher energy requires to generate laser plasma using F-Theta lens with longer focal length.