共查询到20条相似文献,搜索用时 15 毫秒
1.
D.K.Y. Low H. Xie Z. Xiong G.C. Lim 《Applied Physics A: Materials Science & Processing》2005,81(8):1633-1638
Using tightly focused femtosecond laser pulses to irradiate lines in aluminosilicate glass, embedded lines with increased
refractive index, which function as optical waveguides were observed. The pulse energy (4.5–11.2 μJ) and writing speed (50–700 μm/s)
were shown to affect the resultant optical properties of the waveguides such as the magnitude of refractive index change,
core diameter and propagation mode. At pulse energies above 5 μJ, two types of structures were observed, namely an inhomogeneous
void-like structure and a cross-sectional crack-like structure. These structures were found to affect significantly the resultant
waveguiding properties of the irradiated lines. Using pulse energy of 5 μJ or below, single mode waveguides were fabricated.
Raman spectroscopy showed that the fs laser pulses generated structural changes to the aluminosilicate glass. The fabrication
of a 1×4 splitter was also demonstrated.
PACS 42.62.-b; 42.82.-m; 81.05.Kf 相似文献
2.
Phase-shifted Bragg grating waveguides (PSBGWs) were formed in bulk fused silica glass by femtosecond laser direct writing to produce narrowband (22±3) pm filters at 1550 nm. Tunable π and other phase shifts generated narrow passbands in controlled positions of the Bragg stopband, while the accurate placement of multiple cascaded phase-shift regions yielded a rectangular-shaped bandpass filter. A waveguide birefringence of (7.5±0.3)×10(-5) is inferred from the polarization-induced spectral shifting of the PSBGW narrowband filters. 相似文献
3.
V. Diez-Blanco J. Siegel J. Solis 《Applied Physics A: Materials Science & Processing》2007,88(2):239-242
Optical waveguides have been produced by femtosecond-laser writing in a high linear and nonlinear refractive index glass (SF57).
Light guiding occurs nearby a central damaged zone due to the collateral densification caused by shockwaves generated in the
focal volume. High pulse energies are required to induce a modified region capable of supporting a guided mode. An alternative
processing method, based on using multiple structures, has been successfully used for the production of waveguides with controllable
core size at low energies.
PACS 42.82.Et; 42.65.Re; 42.70.Ce; 81.20.–n 相似文献
4.
Single-step writing of Bragg grating waveguides in fused silica with an externally modulated femtosecond fiber laser 总被引:1,自引:0,他引:1
For the first time to our knowledge, high-strength (>30 dB) first-order Bragg grating waveguides were fabricated in bulk fused silica glass in a single-scanning step by modulating a high-repetition-rate femtosecond fiber laser with an external acousto-optic modulator. The modulation induced a waveguide segmentation by delivering controlled bursts of laser pulses to define an array of partially overlapped refractive index voxels. With appropriate choice of modulation frequency and sample scanning speed, low loss waveguides could be formed at high writing speeds to yield sharp Bragg spectral resonances tunable over the 1300 to 1550 nm telecom band. Effects of acousto-optic modulation duty cycle on propagation loss and grating strength are characterized. This modulation method offers facile control and integration of multiwavelength Bragg grating devices to enhance overall functionality of optical circuits in three-dimensional geometries. 相似文献
5.
量子比特在同一时刻可处于所有可能状态上的叠加特性使得量子计算机具有天然的并行计算能力,在处理某些特定问题时具有超越经典计算机的明显优势.飞秒激光直写技术因其具有单步骤高效加工真三维光波导回路的能力,在制备通用型集成光量子计算机的基本单元—量子逻辑门中发挥着越来越重要的作用.本文综述了飞秒激光直写由定向耦合器构成的光量子比特逻辑门的进展.主要包括定向耦合器的功能、构成、直写和性能表征,集成波片、哈达玛门和泡利交换门等单量子比特逻辑门、受控非门和受控相位门等两量子比特逻辑门的直写加工,并对飞秒激光加工三量子比特逻辑门进行了展望. 相似文献
6.
We demonstrate that within a restricted optical pulse duration-pulse energy parameter space tightly focused femtosecond laser radiation can be used to fabricate porous capillaries in bulk fused silica glass by simply moving the laser focus through the material. We show that the rate of penetration of liquids into the porous capillaries can be controlled by the laser polarization, which determines their morphology. The fluid propagation is measured using the form birefringence of nanocrack/nanovoid structures produced inside the capillaries. We also demonstrate the nanofiltration capabilities of the capillaries by separating the relatively small molecules of Rhodamine 6G dye from their solvent. 相似文献
7.
We investigate a flexibly tunable multiwavelength semiconductor-optical-amplifier-based fiber ring laser with continuous wavelength spacing controllability incorporating a superimposed chirped fiber Bragg grating (CFBG). The wavelength spacing of a superimposed CFBG can be continuously controlled by symmetrically modifying the chirp bandwidth of the grating with the specially designed apparatus. We achieve a wide and continuous tuning range of the wavelength spacing from 0.35 to 0.78 nm. The continuous tunability of the wavelength spacing is measured to be ~ +/-0.033 nm/mm. By controlling the reflection bandwidth of the tunable CFBG, we can independently adjust the number of lasing channels from 2 to 23 at the wavelength spacing of 0.51 nm. 相似文献
8.
D. Liu Y. Li R. An Y. Dou H. Yang Q. Gong 《Applied Physics A: Materials Science & Processing》2006,84(3):257-260
We studied the influence of focusing depth on the index change threshold and damage threshold of silica glass irradiated by a focused 120 fs laser beam. Both thresholds increased with the focusing depth. The aspect ratio of the waveguide cross section can be selected by changing the focusing depth. A 5 mm long waveguide was written at the depth of 2100 μm, which was single mode at 632.8 nm and exhibited propagation loss of 0.56 dB/cm. The refractive index change was calculated to be ∼2.47×10-3. The influence of the focusing depth should be considered in multi-layer devices as shown in the fabrication of a 3×3 waveguide array. PACS 42.62.-b; 42.82.Et; 81.05.Kf 相似文献
9.
A single-longitudinal-mode ErYb:glass laser with a linewidth of 90 kHz is demonstrated by locking the laser wavelength to 1552.6 nm with a bulk glass Bragg grating. Using a piezoelectric actuator, the wavelength could be tuned over a range of 0.25 nm (31 GHz) in steps of 17 pm (2.1 GHz), with an output power of a few milliwatts. 相似文献
10.
为了制备具有可控复杂形状和特定化学性质的聚合物微结构,提出了一种飞秒激光直写生物凝胶模板原位合成纳米粒子的方法。首先,采用飞秒激光直写技术加工带有COOH基团的复杂三维结构的生物凝胶模板,用氢氧化钠处理使COOH基团离子化为COO-基团;然后,用金属盐溶液处理,使金属离子与COO-基团螯合,形成纳米粒子结晶核。通过多次循环盐溶液处理步骤,控制模板中纳米粒子的粒径与含量。实验结果表明:所制备的生物凝胶模板具有亚100 nm分辨率和10 μm量级尺寸,纳米粒子含量高达9%。该法简单高效,具有很好的应用前景。 相似文献
11.
In the present work, we have analyzed the use of elliptical beam shaping along with low numerical aperture focusing optics in order to produce circular cross-section waveguides in different materials at large processing depths by direct femtosecond laser writing (100 fs, 800 nm, 1 kHz). A variable slit located before the focusing optics allows to generate a nearly elliptical beam shape and also to reduce the effective numerical aperture of the beam along the shat axis of the ellipse. The focusing optics allows to focus the beam deep inside the sample, which is translated at a constant speed transversely to the writing beam direction. The influence of several experimental parameters (energy per pulse, slit width, processing depth) on the properties of the produced waveguides has been analyzed. The influence of the intrinsic properties of the material (refractive index, composition) has been analyzed by comparing results obtained in fused silica and Er:Yb co-doped phosphate glass. The results obtained show that this approach leads to the successful production of deep subsurface (up to 7 mm) waveguides with circular cross-sections. Preliminary results using chirped pulses in the phosphate glass suggest that temporal pulse shaping can be used as an additional parameter to optimize the guided mode symmetry. 相似文献
12.
Three-dimensional direct femtosecond laser writing of second-order nonlinearities in glass 总被引:1,自引:0,他引:1
Choi J Bellec M Royon A Bourhis K Papon G Cardinal T Canioni L Richardson M 《Optics letters》2012,37(6):1029-1031
We demonstrate that direct femtosecond laser writing in silver-containing zinc and gallium phosphate glass enables generation of three-dimensional (3D) optical second-order nonlinear microstructures having an χ(2) value about 2.5 times that of quartz. The proposed physical model involves photo-reduction, photo-dissociation, and migration of silver species within the glass matrix. 3D laser-written second-order nonlinear structures could become a new class of nonlinear optical components. 相似文献
13.
We theoretically investigated the two methods for densifying the channel spacing of sampled fiber Bragg gratings (SFBGs), the multiple-phase-shift (MPS) method and the linear chirp method, and found that the two methods have similar principle and ability, although the chirp method has an advantage that the tuning of channel spacing is easier. Then we realized channel spacing-tunable SFBGs by use of deformation of ring and S-bend structures by 2- and 3-folds. Finally, we applied the chirp method to realize a wavelength spacing-tunable multiwavelength fiber laser. 相似文献
14.
Spatio-temporal coupling characteristics of ultrafast laser pulses are quantitatively tailored. An asymmetric microstructure is induced in the focal volume when the laser scans perpendicularly to the direction of the spatial chirp in fused silica. The tilted direction reverses when adding a Dove prism into the light path. The sign of the pulse front tilt can be turned from positive to negative by changing the group delay dispersion by steps. We reveal that the tilted direction of a microstructure depends on spatial chirp, and the interplay between spatiotemporal chirp leads to the change of tilted angles. 相似文献
15.
Solgel grating waveguides and their application to the fabrication of external-cavity distributed Bragg reflector (DBR) lasers are demonstrated. A new composition of aluminosilicate material is developed for the fabrication of single-mode waveguides and Bragg reflectors. An average loss of <0.2 dB/cm is measured in the single-mode waveguides at 1550 nm. The reflectors show filtering greater than 97% near 1530 nm, with a bandwidth of ~0.6 nm . The Bragg reflectors are used as feedback resonators for DBR lasers. Single-mode lasing with a sidemode suppression of better than 25 dB is demonstrated. 相似文献
16.
The two-dimensional angular filter based on volume Bragg gratings in photothermorefractive glass for a nanosecond(ns) laser pulse is demonstrated. The experimental results show that the near-field beam quality of the laser pulse was effectively improved. The near-field modulation and contrast ratio were improved by 1.75 and4.48 times, respectively. The power spectral density curves showed that the spatial frequencies more than0.9 mm~(-1)in the x direction and 1.2 mm~(-1)in the y direction were effectively suppressed. 相似文献
17.
Two separate laser diodes emitting near 980 nm were coupled by a thick volume Bragg grating recorded in a photothermorefractive glass. The coupled diodes emitted at the same wavelength with a spectral width narrowed to below the resolution of the spectrum analyzer (<30 pm). Coherent emission at a pumping level greater than five times above the threshold was observed for several months with near-unity visibility of the interference pattern. 相似文献
18.
19.
We investigate the on-line writing identical fiber Bragg grating (FBG) arrays using the phase mask technique. Given the limitation of laser power, the energy density uniformity and the horizontal width of the writing spot cannot be further optimized. The results show that the FBG arrays obtained in the optimal process (drawing speed of 12 ± 0.15 m/min and average tension of 38.2 g) have a central wavelength bandwidth of less than 0.1 nm and an average reflectivity of 0.26%. Thus, the phase mask method is a promising alternative for on-line writing identical FBG arrays.On-line writing identical and weak fiber Bragg grating arrays. 相似文献
20.
Miaomiao Xu Ruiyun He Shuqian Sun Javier R. Vázquez de Aldana Feng Chen 《固体物理学:研究快报》2013,7(11):1014-1017
By using femtosecond laser micromachining, optical wave guides in both depressed cladding and dual‐line configurations have been produced in LiTaO3 crystal. The guiding properties and the thermal stability have been investigated for both geometries, which exhibit different performance. Depressed cladding waveguides support guidance along both extraordinary and ordinary index polarizations, while dual‐line waveguides support only extraordinary index polarization. Thermal annealing has been proved to be an effective method to reduce the propagation losses. For the cladding waveguide, the lowest propagation loss was as low as 0.38 dB/cm after the annealing treatment at 400 °C. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献