激光直写制备薄膜铂电阻技术研究

为了研究激光直写技术在制备薄膜铂电阻中的应用,采用激光直写制备了薄膜厚度为2m的铂电阻。探讨了激光直写技术制备薄膜铂电阻的原理,以条形铂电阻为例,研究了激光参量对铂电阻形状的影响,在最优的激光脉冲频率18kHz、激光扫描速率100mm/s的参量下,制备了实际电阻约为0.37的条形薄膜铂电阻,最后检验了薄膜铂电阻的电阻值。结果表明,铂电阻的宽度分别随激光脉冲频率和激光扫描速率的增大而增大;制备的电阻边缘整齐,表面平整,电阻实际值与理论值只有0.8%的相对误差,吻合很好。     

飞秒激光加工光波导的工艺与传输特性研究

利用飞秒激光横向直写方式加工光波导,采用散射光测量法分析了光波导的传输损耗。为了提高光波导的传输性能,分析了不同数值孔径的聚焦物镜、加工速度和加工能量对光波导传输损耗的影响。实验结果表明,聚焦物镜数值孔径为0.25,激光功率为6 m W,加工速度在45~60μm/s时,飞秒激光加工的光波导具有较好的传输性能,其传输损耗低于-0.2 d B/cm。     

医用CO2激光传输用空芯波导的研制

本文作者设计并制备了一种新型的CO2激光传输用空芯波导。除了6μm-9μm处的基团吸收外，这种空芯波导在整个中红外区域的损耗都很小，在10.6μm波长处的损耗约为0.4db/m，传输能量为10W时，可以稳定传输20分钟以上，基本上可以满足CO2激光在医疗中的应用。     

飞秒激光在掺Yb~(3+)磷酸盐玻璃中刻写双线型光波导的研究

利用重复频率为50 k Hz,中心波长为790 nm,脉冲宽度为140 fs的飞秒激光脉冲在掺Yb3+磷酸盐玻璃中刻写双线型光波导。研究了双线间距,激光脉冲能量和刻写速度对波导形成的影响,并测试了不同刻写参数下波导的导光模式。实验结果表明,在双线间距为35μm,激光脉冲能量为1.0μJ,刻写速度为600μm/s的条件下写入的光波导导光性能最优;利用近场模式重建了激光诱导该波导的折射率二维分布,波导区域相对于基质的最大折射率改变为1.5×10-4,并利用散射法测试了波导的传输损耗,传输损耗为1.56 d B/cm。发现了波导具有偏振导光现象,偏振态平行于双线方向的激光可以导通,偏振态垂直于双线方向的激光不能导通。     

CO2激光直写制作聚酰亚胺多模波导技术的研究

为了研究适合制作大面积波导的CO2激光直写制作聚酰亚胺多模波导技术,采用理论模拟和工艺研究的方法,通过建立激光加工模型,得到了激光扫描线的温度分布与加工参量的关系,提出了增加波导侧面陡直性的方法;通过对实验结果的分析,研究了加工参量对波导材料性能、波导结构和表面粗糙度的影响。结果表明,控制激光功率密度、直写速率和光阑位置可以控制波导的宽度、侧面陡直性和表面粗糙度。     

兆赫兹飞秒激光脉冲制备“珍珠串”光波导

对纳焦量级的高重频飞秒激光在玻璃内部制备"珍珠串"光波导进行了研究。在制备过程中向外辐射出白光连续光谱,实验结果表明飞秒激光脉冲能量和运行速度对"珍珠串"光波导的形成有较大影响,在激光脉冲能量10.5 nJ,玻璃运行速度为0.2 mm/s情况下制备的"珍珠串"光波导结构较好,"珍珠串"的横向宽度为19μm,"珍珠串"的间隔周期为20μm。制备的"珍珠串"光波导能对玻璃内传输的He-Ne激光进行有效约束。最后对玻璃内部制备"珍珠串"光波导的机制进行了分析。     

激光直写法制备条形光波导中的功率密度阈值

采用溶胶-凝胶法(sol-gel)在Si基SiO2衬底上制备了SiO2-TiO2芯层薄膜,构成了以SiO2为下包层,空气为上包层的平面光波导。利用光纤激光器对平面波导的芯层进行直写,结合后续的化学腐蚀工艺得到了SiO2-TiO2条形光波导,并着重研究了激光直写波导过程中存在的功率密度阈值以及阈值随薄膜预热处理温度的变化关系。研究结果表明,激光直写SiO2-TiO2波导存在起始收缩阈值和烧蚀损伤阈值;随着薄膜热处理温度的提高,两个阈值同时增大,其中损伤阈值的增大趋势要大于收缩阈值;因而薄膜可承受的直写光斑直径变小,所得波导宽度显著减小。最后对直写制得条形光波导的导光性能作了测试分析,验证了波导的三维导光性。     

飞秒激光在钛蓝宝石晶体中刻写双线型波导的研究

钛蓝宝石晶体作为一种重要的激光介质,具有宽带的吸收光谱及宽带可调谐的发射光谱等特性,使其在集成光学中有广泛的应用前景。这里利用重复频率为1 k Hz,中心波长为800 nm,脉冲宽度为120 fs的飞秒脉冲激光在钛蓝宝石晶体中横向刻写双线型波导,系统地研究了激光写入晶体深度、刻写速度以及波导双线间距对波导导光情况的影响,在写入激光脉冲能量为2μJ,写入深度为175μm,刻写速度为90μm/s,波导双线间距为26μm的条件下,得到一组导光模式较优的双线波导并发现其具有偏振导光现象。利用波导的近场模式强度分布重构了其折射率分布图,得到最大的折射率增加量为1.9×10-4。用散射法测试了光波导的传输损耗为1.82 d B/cm。     

硬脂酸质子交换X切LiNbO3光波导的制备技术研究

利用无毒、无腐蚀性的硬脂酸作为交换质子源,研究了在X切LiNbO3晶片上制作单模条形光波导的工艺技术。通过对平板光波导的交换及退火特性的研究,确定了获得单模条形光波导的工艺参数,制作并测试了条宽不等的X切Y传LiNbO3单模条形光波导。结果表明该工艺条件下制作的条宽为6μm的单模波导实现了小于1dB/cm的传输损耗,为采用硬脂酸作为交换质子源研制X切Y传LiNbO3集成光波导器件奠定了基础。     

硬脂酸质子交换X切LiNbO3光波导的制备技术研究

利用无毒、无腐蚀性的硬脂酸作为交换质子源, 研究了在X切LiNbO3晶片上制作单模条形光波导的工艺技术。通过对平板光波导的交换及退火特性的研究, 确定了获得单模条形光波导的工艺参数, 制作并测试了条宽不等的X切Y传LiNbO3单模条形光波导。结果表明该工艺条件下制作的条宽为6μm的单模波导实现了小于1dB/cm的传输损耗, 为采用硬脂酸作为交换质子源研制X切Y传LiNbO3集成光波导器件奠定了基础。     

飞秒激光直写透明光学材料光波导的研究进展

综述了飞秒激光直写光波导的加工过程和表征方法、可直写形成光波导的不同透明光学材料以及直写光波导应用的进展。总结了飞秒激光直写引起的折射率变化与材料有关,同时还依赖于加工的脉冲能量、脉冲宽度、偏振以及扫描速度等。指出飞秒激光微加工在光子器件领域的有很好的应用前景。     

Low-loss channel waveguide on high-energy-beam sensitive glass

We report on the fabrication of optical channel waveguide on a high-energy-beam sensitive glass using a maskless nonphotolithographic processing technique. Laser direct writing and one-step chemical etching result in high quality channel waveguide with a propagation loss of about -0.27 dB/cm at 1550-nm wavelength.     

高重复频率飞秒激光烧蚀熔融石英制作单偏振微结构波导

利用中心波长为1040nm、脉宽为190fs、重复频率在200～5000kHz之间可调的飞秒激光对熔融石英进行微加工。研究了烧蚀阈值随脉冲重复频率、扫描速度的变化规律,阐明不同参数下热扩散效应及热累积效应对烧蚀过程的主导作用。在最优化条件下,制作了双线波导,可以对1040nm激光实现圆形基模传输。进一步制作了椭圆晶胞的六角微结构波导,对1040nm激光可以输出近高斯强度分布的基模,模场面积达到247.48μm2。该微结构波导可实现单偏振传输,消光比达9.05,波导数值孔径约0.017。     

Spectral Loss Characterization of Femtosecond Laser Written Waveguides in Glass With Application to Demultiplexing of 1300 and 1550 nm Wavelengths

Femtosecond laser written waveguides in glass were characterized across the full telecom spectrum to gain insight into waveguide loss mechanisms, and to aid in the design of a low-loss 1300/1550 nm wavelength demultiplexer. A lambda^-4 wavelength scaling of propagation loss confirms Rayleigh scattering as a principal loss mechanism. Laser exposure was optimized for generating low-loss directional couplers with high isolation between the 1300 and 1550 nm bands. Dispersive coupling in the straight and curved wavelength regions was balanced with a 1.5-fold difference in 1300 and 1550 nm beat lengths, leading to the first demonstration of 1300/1550 nm demultiplexer written with a laser. A minimum interaction length of 3.2 mm, ~2 dB insertion loss and channel isolations of 16.7 and 18.8 dB are reported.     

红外激光传输用聚苯乙烯—银—玻璃基体空心波导研究

利用液相镀膜法研制成了性能较好的传输用聚苯乙烯－银－玻璃基体小直径空心波导,波导长度达到1m左右,波导直径为800－1200μm,对于CO2激光（10.6μm）的传输损耗低达1.73dB/m,损伤阈值高于11.2W(17.2W/mm^2)。实验结果表明,聚苯乙烯－银－玻璃基体小直径空心波导适用于医学等领域CO2激光传输的要求,并有望在其他红外波段的激光能量传输中得到应用。     

Fabrication of single-mode polymeric optical waveguides bylaser-beam writing

A laser-beam writing system is developed for large-area optical waveguide fabrication. Single-mode embedded channel optical waveguides are successfully fabricated on both 4- and 8-in silicon substrates using deuterated fluoromethacrylate polymers by laser-beam writing in photoresist and dry etching. The propagation loss of the waveguides is as low as 0.1 dB/cm at 1.3 μm     

Waveguide Interconnection in Silica-Based Planar Lightwave Circuit Using Femtosecond Laser

The interconnection of waveguides inside a silica- based planar lightwave circuit (PLC) is demonstrated both two- and three-dimensionally by using a femtosecond laser. The waveguides written with a femtosecond laser can be successfully connected to waveguides inside a PLC with low loss. Unlike previous work on the direct writing of 2-D and 3-D waveguides in bulk glass, the waveguide must be written a few tens of micrometers beneath the surface of a PLC composed of multilayers of different glasses. To realize a low-loss waveguide, we studied the sensitivity difference for femtosecond pulses in each layer in detail and developed a multiple-scanning technique with a femtosecond laser for writing waveguides. In addition, we investigated a mode-field (MF) diameter control technique to allow us to achieve the low-loss interconnection of PLC and written waveguides. We also studied particular problems caused by nonlinear optical effects, such as the positional displacement of written waveguides from the focal point. As a result, we achieved a low-loss waveguide with almost the same MF diameter as a PLC waveguide and performed the first demonstration of interconnection between PLC waveguides. The excess losses at 1550 nm were 1.4 and 2.3 dB for 2-D and 3-D interconnection, respectively.      

Efficient light transmission through InP-based photonic crystalwaveguides

Very efficient light transmission over a length of several millimetres through linear photonic crystal slab waveguides, patterned into an InGaAlAs waveguiding layer on InP substrate, is demonstrated. Quantitative evaluation of the light propagation in these waveguides, using the Fabry-Perot resonance method, yields a minimum loss of 1.6 dB/mm, for a waveguide with seven missing rows at 1550 nm wavelength