Current Optics and Photonics
Vol. 9 No. 3 (Jun. 2025)
한국광학회지
Vol. 36 No. 3(Jun. 2025)
K-Light
vol. 8 no. 2(Apr. 2025)
한국광학회 공식 SNS 계정 바로가기
트위터
인스타그램
![[Editor's Pick] Current Optics and Photonics Vol. 9 no. 3 (2025 Jun)_2nd](https://www.osk.or.kr/upload/posts_thumb/2025/06/1750812446_36548300_559638138-thumb.jpg)
[Editor's Pick] Current Optics and Photonics Vol. 9 no. 3 (2025 Jun)_2nd
10 W 15 ns 300 kHz Red-emission of 650 nm Based on Third-harmonic Generation
from Thulium-doped Fiber Laser at 1950 nm
Jinju Kim*, Yong-Ho Cha, Woo-Sang Yu, and Kwang-Hoon Ko
Current Optics and Photonics Vol. 9 No. 3 (2025 June), pp. 202-208
DOI: https://doi.org/10.3807/COPP.2025.9.3.202
Fig. 1 The experimental setup of the 650 nm red laser system includes the following components: Laser diode (LD), isolator (ISO), bandpass filter (BPF), fiber amplifier (FA), electro-optic modulator (EOM), acousto-optic modulator (AOM), circulator, secondharmonic generator (SHG), and third-harmonic generator (THG).
Keywords: Fiber laser, Frequency tripling, PPLN, Thulium laser
OCIS codes: (140.3280) Laser amplifiers; (140.3460) Lasers; (140.3510) Laser, fiber
Abstract
A 10 W, 15 ns, 300 kHz pulsed laser emitting at 650 nm was developed through second- and thirdharmonic generation based on a 20 W pulsed thulium-doped all-fiber laser operating at 1950 nm. The 1950 nm all-fiber laser, which was constructed using a master oscillator power amplifier configuration, comprised one continuous-wave amplifier, two pulsed pre-amplifiers, and a final main amplifier. The amplified output power at the fundamental wavelength was 20 W and it was frequency-tripled to 650 nm using two MgO-doped periodically poled lithium niobate crystals. The maximum emission power achieved at 650 nm was 10 W and the conversion efficiency from 1950 nm to 650 nm was around 50%. To the best of our knowledge, this represents the first development of a nanosecond-pulsed 650 nm emitting source that attains an output power of 10 W through the frequency-tripling of a thulium-doped fiber laser.
![[Editor's Pick] Current Optics and Photonics Vol. 9 no. 3 (2025 Jun)_1st](https://www.osk.or.kr/upload/posts_thumb/2025/06/1750812353_58937600_1361604013-thumb.jpg)
[Editor's Pick] Current Optics and Photonics Vol. 9 no. 3 (2025 Jun)_1st
MEMS Actuators for Tunable Waveguide Devices in Photonic Integrated Circuits: A Brief Review
Dongju Choi, Young Jae Park, Man Jae Her, and Sangyoon Han*
Current Optics and Photonics Vol. 9 No. 3 (2025 June), pp. 185-195
DOI: https://doi.org/10.3807/COPP.2025.9.3.185
Fig. 1 Schematic illustration of microelectromechanical systems (MEMS)-based optical phase shifters using mecha nically movable waveguides: (a) 3D schematic depicting two parallel waveguides (main and perturbing waveguides), where the perturbing waveguide can move either horizontally (inplane actuation) or vertically (out-of-plane actuation). Top of (b) and left-side of (c) are optical mode profiles with distant waveguides for in-plane and vertical configurations. Bottom of (b) and right-side of (c) are optical mode profiles showing significant mode expansion when waveguides are brought closer in both in-plane and vertical directions.
Keywords: Actuator, Microelectromechanical systems, Photonic integrated circuits, Waveguide
OCIS codes: (230.0230) Optical devices; (230.4685) Optical microelectromechanical devices; (230.7370) Waveguides; (250.5300) Photonic integrated circuits;
Abstract
Microelectromechanical systems (MEMS)-based tuning methods offer promising solutions for dynamically controlling optical properties in photonic integrated circuits (PICs) to address the limitations associated with traditional approaches that rely on direct modulation of the material’s refractive index. Conventional methods such as thermo-optic, plasma dispersion, and electro-optic modulation, face significant challenges including high energy consumption, limited refractive index change, and issues with heat dissipation and optical losses. By contrast, MEMS-based actuators directly reposition optical components, enabling reduced device footprints, negligible static power consumption, rapid response times, and improved reliability. This paper systematically explores the operating principles and design characteristics of five representative MEMS actuator technologies widely used in tunable waveguide devices: In-plane comb-drive actuators, cantilever actuators, gap-reducing actuators, vertical digital actuators, and vertical comb-drive actuators. Each actuator type is analyzed for its distinct advantages and challenges, with considerations such as device compactness, switching speed, voltage requirements, and robustness against reliability issues such as pull-in phenomena and stiction. The insights presented emphasize the substantial potential of MEMS-based tuning methods to advance the scalability, energy efficiency, and performance of next-generation PICs. Continued research into improving actuator performance, including increased operation speed, lower operating voltages, and further miniaturization, will be critical to achieving widespread integration and adoption.
 |
 |
 |
 |
 |
 |
|
 |
 |
 |
 |
 |
 |
|
 |
 |
 |
 |
 |
 |
 |
