- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
High-power, cascaded random Raman fiber laser with near complete conversion over wide wavelength and power tuning
摘要： Cascaded Raman fiber lasers based on random distributed feedback (RDFB) are proven to be wavelength agile, enabling high powers outside rare-earth doped emission windows. In these systems, by simply adjusting the input pump power and wavelength, high-power lasers can be achieved at any wavelength within the transmission window of optical fibers. However, there are two primary limitations associated with these systems, which in turn limits further power scaling and applicability. Firstly, the degree of wavelength conversion or spectral purity (percentage of output power in the desired wavelength band) that can be achieved is limited. This is attributed to intensity noise transfer of input pump source to Raman Stokes orders, which causes incomplete power transfer reducing the spectral purity. Secondly, the output power range over which the high degree of wavelength conversion is maintained is limited. This is due to unwanted Raman conversion to the next Stokes order with increasing power. Here, we demonstrate a high-power, cascaded Raman fiber laser with near complete wavelength conversion over a wide wavelength and power range. We achieve this by culmination of two recent developments in this field. We utilize our recently proposed filtered feedback mechanism to terminate Raman conversion at arbitrary wavelengths, and we use the recently demonstrated technique (by J Dong and associates) of low-intensity noise pump sources (Fiber ASE sources) to achieve high-purity Raman conversion. Pump-limited output powers >34W and wavelength conversions >97% (highest till date) were achieved over a broad – 1.1μm to 1.5μm tuning range. In addition, high spectral purity (>90%) was maintained over a broad output power range (>15%), indicating the robustness of this laser against input power variations.
关键词： wavelength conversion,spectral purity,random distributed feedback,Raman fiber laser,high-power
更新于2025-09-23 15:19:57
-
Compact dual-gas sensor for simultaneous measurement of atmospheric methane, and water vapor using a 3.38?μm antimonide-distributed feedback laser diode
摘要： A simple, compact sensor involving a continuous-wave 3.38 mm distributed feedback laser in combination with a novel compact dense-pattern multipass cell was demonstrated for simultaneous measurement of atmospheric methane and water vapor. The calibration-free direct absorption spectroscopy approach was adopted for data generation and processing. Allan deviation analysis indicates that minimum detection limits (1s) of 11.0 ppb for CH4 and 100 ppm for H2O were achieved with a 1-s integration time at an optimum pressure of 50 Torr. Atmospheric environmental mixing ratios of these two gases were recorded and analyzed. This newly developed mid-infrared dual-gas sensor is very suitable for trace gas sensing in weight-limited unmanned aerial vehicle- or balloon-embedded field observations.
关键词： Multipass cell,Laser sensors,Water vapor,Distributed feedback laser,Laser absorption spectroscopy,Methane
更新于2025-09-19 17:13:59
-
Laser oscillation at an intended wavelength from a distributed feedback structure on anisotropic organic crystals
摘要： An organic laser device is constructed as distributed feedback (DFB) type using an anisotropic single crystal of an organic semiconductor oligomer BP3T. The DFB structure is formed on top of the crystal via an interference exposure technique of a positive type photoresist. In the DFB structure, both the phase matching condition and waveguide condition must be fulfilled. Under these conditions, the effective refractive indices can be precisely predicted for a BP3T crystal, and they vary depending upon the crystal thickness. As a result, the device produces a single-mode laser oscillation at an intended wavelength (typically ～569 nm). The present study enables us to design a down-to-earth laser device based on an anisotropic organic semiconductor crystal toward practical use.
关键词： organic laser,single-mode laser oscillation,anisotropic organic crystal,BP3T,distributed feedback
更新于2025-09-19 17:13:59
-
Sub-400 nm film thickness determination from transmission spectra in organic distributed feedback lasers fabrication
摘要： The design and fabrication of thin-film based organic optoelectronic devices require knowledge of the film optical properties. A low-cost and non-destructive method often used for optical characterization of films is the well-established spectrophotometric envelope method. However, this method is typically limited to thickness above 400 nm, a value often higher than that of the films involved in these devices. This paper studies a procedure to obtain the thickness of sub-400 nm active films from their spectrophotometric trace when the refractive index is previously known. The proposed procedure is based on comparing the experimental transmission spectrum in the transparent spectral window with that obtained by simulation. The capabilities of the proposed method are demonstrated here by its application in the fabrication of organic distributed-feedback lasers where a fine control of film thickness is important to obtain an optimized and reproducible response. Results were verified with other techniques, such as ellipsometry and profilometry. Thus, with the proposed method, film thickness can be easily determined down to 40 nm maintaining an accuracy of about 5 nm even for films with low refractive index (1.5-1.7). Different methods to determine refractive index of these films are also discussed.
关键词： Optical characterization,Thin film thickness,Transmission spectra,Distributed feedback lasers
更新于2025-09-19 17:13:59
-
[IEEE 2019 21st International Conference on Transparent Optical Networks (ICTON) - Angers, France (2019.7.9-2019.7.13)] 2019 21st International Conference on Transparent Optical Networks (ICTON) - Applications of Single Frequency Blue Lasers
摘要： Gallium nitride (GaN) sources are becoming a regular part of today’s world and are now key devices for lighting infrastructures, communications systems and quantum applications, amongst others. In particular, many applications have seen the shift from LEDs to laser diodes to make use of higher powers, higher bandwidths and increased transmission distances. Laser communication systems are well established, however there are applications where the ability to select a single emitted wavelength is highly desirable, such as quantum atomic clocks or in filtered communication systems. Distributed feedback (DFB) lasers have been realised emitting at a single wavelength where the grating structure is etched into the sidewall of the ridge. The main motivation in developing these lasers is for the cooling of ions in atomic clocks; however their feasibility for optical communications is also explored. Narrow linewidth lasers are desirable and this paper will explore how this is achieved. Data rates in excess of 1 Gbit/s have also been achieved in a directly modulated, unfiltered system. These devices lend themselves towards wavelength division multiplexing and filtered optical communications systems and this will be analysed further in the work presented here.
关键词： gallium nitride,optical atomic clocks,optical communications,distributed feedback lasers
更新于2025-09-19 17:13:59
-
[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Study on DFB semiconductor laser based on sampled moiré grating integrated with grating reflector
摘要： We proposed a new kind of distributed feedback (DFB) semiconductor laser based on the sampled moiré grating (SMG) integrated with a grating reflector (GR). Coupling coefficient along laser cavity can be easily controlled and π phase shift (π-PS) can be introduced by SMG. The GR, which is a uniform sampled grating, only provides reflection for facet light. The both facets are coated with anti-reflection coatings (AR/AR) to avoid the influence of facet-phase. Therefore, more output power, single longitudinal mode (SLM) operation and high wavelength precision can be simultaneously achieved. An 8-channel DFB laser array based on the proposed structure has also been simulated.
关键词： distributed feedback lasers,sampled moiré grating,grating reflector,laser array
更新于2025-09-16 10:30:52
-
[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Two-color random fiber laser with flexible power proportion based on phosphosilicate fiber
摘要： A two-color random fiber laser based on phosphosilicate fiber with flexible power proportion and 117 nm wavelength interval was demonstrated. The power proportion of the silica-related Stokes light ranged from 99.0 % to 0 %.
关键词： flexible power proportion,random distributed feedback Raman fiber laser,phosphosilicate fiber,two-color
更新于2025-09-16 10:30:52
-
High-coupling distributed feedback lasers for the 1.55 μm spectral region
摘要： A technique for the development of high-coupling distributed-feedback (DFB) lasers for the 1.55 mm spectral region is described. The lasers demonstrate stable single-frequency generation in a broad temperature range with a maximum side-mode suppression ratio of more than 30 dB.
关键词： single-frequency lasing,distributed feedback,semiconductor laser,side-mode suppression ratio
更新于2025-09-16 10:30:52
-
[IEEE 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - St. Petersburg, Russia (2019.10.17-2019.10.18)] 2019 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Distortion Analysis of Interferometric Signal with Auxiliary Emission Modulation in Semiconductor Laser
摘要： The results of analysis of distortion of interferometric signal of a semiconductor laser with the current modulation are presented. The mathematical model of the interferometric signal was refined based on experimental data. Measurements were performed for harmonic and triangular auxiliary modulation, and the effect of laser thermal stabilization on the modulation of the interferometric signal was studied.
关键词： phase modulation,external cavity laser,thermal stabilization,distributed feedback laser,distortion of interferometric signal
更新于2025-09-16 10:30:52
-
2D Bragg Resonators Based on Planar Dielectric Waveguides (from Theory to Model-Based Testing)
摘要： Using analytical approaches and CST Microwave Studio 3D simulation, the electrodynamic characteristics of 2D Bragg resonators based on planar dielectric waveguides with doubly periodic corrugation are theoretically analyzed. Such resonators are of great interest to obtain directed narrow-band radiation in heterolasers with large active regions. Model electrodynamic experiments on the “cold” testing of such structures in the millimeter range are performed. Good agreement between the experimental and simulation results is shown, including the existence of the highest-Q mode within the Bragg reflection band in the absence of defects in the periodicity.
关键词： planar dielectric waveguides,two-dimensional distributed feedback,heterolasers
更新于2025-09-16 10:30:52