Direct Laser Writing Facility for Fabrication of Submicron Mask

Direct laser writing technique has become a well-established, multi-functional and flexible method for fabricating high quality diffractive optical elements. We propose and build a maskless direct laser writing system with the ability to produce a sub-micron feature size. The high precision lithography is realized by using the astigmatic autofocus method. The minimum feature size of the system, breaking through the diffraction limit with the chromium layer, can achieve 300hm with the 405nm blue laser. A 50 x 50ram2 chromium grating mask with a period of 1 #m and line width of 300 nm is fabricated. This facility will be useful for the fabrication of large-scale submicron diffraction optical elements in the future.     

Writing Fiber Grating of Different Wavelength Using the Same Phase Mask

Chirped fiber grating was used in dispersion compensator. We tried to use the same phase mask to write fiber grating of different wavelength with two methods to reduce the price of the fiber grating.     

一种利用相位掩模版对光栅波长进行微调的光栅刻写方法

提出并实验证实了一种刻写光栅时既能保护相位版又能对光栅的反射波长进行微调的方法.通过调整光纤和相位版之间的距离,利用1 550 nm单模光纤和掺铒分别实现了0.48 nm和2.2 nm的光栅反射波长的调节.在相位版和光纤之间的距离保持在3 mm的条件下,既可以保护相位版又可以获得高质量的光栅.     

A Tunable Dual-Wavelength Fiber Ring Laser with a Fabry-Perot Laser Diode in an External Injection Seeding Scheme

A tunable dual-wavelength fiber ring laser with a Fabry-Perot laser diode is proposed and demonstrated. The dual-wavelength outputs have the optical side-mode-suppression-ratio (SMSR) over 31 dB. The wavelength tuning range can be up to 9 nm.     

光纤型宽带可调连续波差频产生中红外激光器

报道一种新型光纤化宽带可调连续波中红外激光器系统,该激光系统采用准相位匹配(QPM)的差频产生(DFG)技术,非线性晶体为多周期的周期性极化掺镁铌酸锂晶体(PPMgLN),掺镱光纤激光器(YDFL)用作抽运光源,可调激光器经掺铒光纤放大器(EDFA)功率提升后作为信号光源。利用建立的准相位匹配-差频产生系统,获得了连续波中红外差频光输出;实验发现,温度导致相位失谐的半峰全宽(FWHM)为4.5℃;通过优化选择晶体周期,并结合调节信号光波长和控制温度,该准相位匹配-差频产生系统可在3.1~3.6μm内连续调谐。     

Variable Wavelengths Fiber Bragg Gratings Written with A Phase Mask and Four Prisms

Using only one diffractive element, the Talbot interferometer provides a robust and inherently stable method for reproducing fiber Bragg gratings with variable wavelengths, and reduces the complexity of the fiber grating fabrication system. However, the usable length of the grating is limited by the practical length of the mirrors. This paper presents a phase mask with two fixed prisms and two rotational prisms to inscribe fiber Bragg gratings with variable Bragg wavelengths. In this system, the fiber Bragg grating is inscribed by UV interference stripes of 193 nm derived from two rotational prisms and two fixed prisms, where phase mask is used as a beam splitter of ±1 order diffraction light. It is noteworthy that the tunable phase mask interferometer decreases the demand of the length of prism evidently.     

Variable Wavelengths Fiber Bragg Gratings Written with A Phase Mask and Four Prisms

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｓｉｎｃｅｔｈｅｆｉｂｅｒｗａｓｐｌａｃｅｄｄｉｒｅｃｔｌｙｂｅｈｉｎｄｔｈｅ ｐｈａｓｅｍａｓｋ ,ｗｈｉｃｈｗａｓｏｒｉｇｉｎａｌｌｙｄｅｍｏｎｓｔｒａｔｅｄｂｙＫ .Ｏ .Ｈｉｌｌｅｔａｌ.ｉｎ 1 993[1] ,ｔｈｉｓｍｅｔｈｏｄｈａｓｂｅｅｎｕｓｅｄｗｉｄｅｌｙｆｏｒｗｒｉｔｉｎｇｆｉｂｅｒＢｒａｇｇ ｇｒａｔｉｎｇ .Ｈｏｗｅｖｅｒ ,ｔｈｅｃｏｎｔａｃｔｔｅｃｈｎｉｑｕｅｏｆｐｈａｓｅｍａｓｋｃａｎｏｎｌｙｉｎｓｃｒｉｂｅｔｈｅｆｉｂｅｒＢｒａｇｇ ｇｒａｔｉｎｇｗｉｔｈ…     

Design of an Optical Fiber Device for Pumping a Double-Clad Fiber Laser with a Laser Diode Bar

Pumping of a rare-earth-doped double-clad fiber laser with a GaAIAs laser diode bar requires imaging the near field output of a 1 cm long one-dimensional linear array of tens of multi-mode laser diode sources onto a two-dimensional oblong cross section approximately matching the fiber’s first cladding shape. This work describes the design and preliminary implementation of a device (here called a high brightness geometric transformer) that achieves this transformation with minimum brightness loss. This is done by imaging the laser diode bar near field using a fast cylindrical micro-lens onto a linear array of N (≈10) soft-glass, thin-clad rectangular fibers; in turn, the fibers’ output ends are arranged to form a stack that matches the required first cladding shape. For a typical 20W CW, laser diode bar with brightness of 25 mW·μm²·sr^-1, the geometric transformer output brightness is 0.6 mW·μm^-2·sr⁻¹, i.e., there is a ·40 intermediate loss of brightness. If the output of the geometric transformer is used to pump a Nd-doped double-clad fiber laser, an overall brightness gain of ·340 can be achieved.Presented at the International Commission of Optics Topical Meeting, Kyoto, 1994.     

Linewidth of Semiconductor-Optical Fiber Ring External Cavity Laser with Tunable Optical Fiber F-P Cavity

１ＩｎｔｒｏｄｕｃｔｉｏｎＮａｒｏｗｌｉｎｅｗｉｄｔｈｔｕｎａｂｌｅｓｉｎｇｌｅｆｒｅｑｕｅｎｃｙｓｅｍｉｃｏｎｄｕｃｔｏｒｌａｓｅｒｓａｒｅｎｅｄｆｏｒａｐｐｌｉｃａｔｉｏｎｓｉｎｃｏｈｅｒｅｎｔｃｏｍｍｕｎｉｃａｔｉｏｎ，ｃｏｈｅｒｅｎｔｄｅ...     

窄线宽高信噪比可调谐掺Er3+光纤激光器

基于偏振态调谐原理,利用多个偏振控制器在环形腔掺Er3+光纤激光器中实现了连续可调谐、窄线宽、高信噪比的单频激光输出.连续调谐宽度达22 nm (1538～1560 nm),3 dB谱线宽度小于0.1 nm,光信号-自发辐射噪音比大于45 dB,最大输出功率约1 mW.在10～50 mW泵浦功率范围内,输出功率波动幅度小于1 dB.在室温下,工作数十个小时,中心波长漂移小于0.05nm.     

Generation of Optical Vortex Using a Spiral Phase Plate Fabricated in Quartz by Direct Laser Writing and Inductively Coupled Plasma Etching

A simple, economical and reliable technique is proposed for fabricating a spiral phase plate （SPP） in a quartz substrate to generate optical vortex with a unit topological charge at the wavelengths of 632.8nm. The spiral phase plate is first formed in the photoresist by direct laser writing lithography and then transferred into the quartz substrate by inductively coupled plasma etching. The performance of the fabricated SPP is verified by using beam intensity distribution, which is in agreement with the theoretical calculation result. The interference measurement suggests that we have succeeded to generate optical vortex with a unit topological charge with the fabricated SPP.     

Continuous True-Time-Delay System Employing a Novel Tunable Chirped Fiber Grating Delay Line and a Sampled Grating Based Multiwavelength Fiber Laser

A photonics true-time-delay system for phased array antenna beam steering employing a novel tunable chirped fiber grating delay line and a multi-wavelength erbium-doped fiber ring laser source based on a sampled grating filter is proposed. The tunable chirped fiber grating, which act as a continuous time-delay element, is achieved by bending a uniform fiber Bragg grating bonded at a slant onto the lateral surface of a simply supported beam. This technique allows the dynamic control of the chirp rate and spectral width of the grating without center wavelength shift. By adjusting the chirp rate of the fiber grating via bend strain, this kind of tunable chirped fiber grating could achieve very low and adjustable delay times, therefore provides higher angle resolution for scanning microwave beam, even the wavelengths of laser source are fixed and un-tunable. The true-time-delay system using proposed tunable chirped fiber grating delay element and sampled grating based laser source is constructed and demonstrated experimentally.     

A Tunable Er3+-Doped Fiber Laser by Use of an Integrated Optics Mach-Zehnder Interferometer

Wavelength tunability of an Er³⁺-doped fiber laser is reported by the use of an integrated optics Mach-Zehnder interferometer driven electro-optically. A pump laser threshold of 5 mW and a continuous tunable band from 1530 nm to 1554 nm are achieved with a drive voltage varying between 0 to +7 volts. An evaluation of the design and improvements are given based on the experimental and theoretical analysis.     

A Tunable Er3+-Doped Fiber Laser by Use of an Integrated Optics Mach-Zehnder Interferometer

Wavelength tunability of an Er³⁺-doped fiber laser is reported by the use of an integrated optics Mach-Zehnder interferometer driven electro-optically. A pump laser threshold of 5 mW and a continuous tunable band from 1530 nm to 1554 nm are achieved with a drive voltage varying between 0 to +7 volts. An evaluation of the design and improvements are given based on the experimental and theoretical analysis.     

利用一块相位掩模和两块棱镜改变光纤光栅的写入Bragg波长

一种相位掩模干涉仪被用于写入不同的Bragg波长的。在该系统中,光纤光栅是由来自两可旋转棱镜所形成的紫外干涉条纹写入的,其中,相位掩模被用作&;#61617;1级衍射光的分束器。并且,当两块顶角由相位掩模的&;#61617;1级衍射角和棱镜折射率确定的棱镜的底部相互平行放置时,该相位掩模给出了Bragg波长的参考值。当Bragg波长的移位为1 nm时,棱镜最大的旋转角为1 degree,最小的旋转角是~2.4 minute。与Talbot干涉仪中平面镜的旋转角~23 second/nm相比,该相位干涉仪中棱镜的旋转精度降低了2~3个数量级。替代了许多具有不同光栅周期的相位掩模,该可调谐相位掩模干涉仪仅用一块相位掩模和两块旋转棱镜就实现了写入具有不同Bragg波长的光栅。     

Photobleaching of Submicron DAST Crystals in a PMMA Film by Direct Laser Writing

Optics and Spectroscopy - Selective photobleaching of DAST (trans-4'-(dimethylamino)-Nmethyl-4-stilbazolium tosylate) non-linear crystals in a 2-μm-thick polymethacrylate film using direct...     

高分辨率衍射图形的DMD并行激光干涉直写

通过将数字微反射镜（Digital Micro-mirror Device,DMD）输入阵列图形微缩干涉成像,激光干涉直写系统在光刻胶板上得到缩小的干涉光斑图形,像素特征尺寸3.5 μm,干涉条纹周期1 μm.控制刻蚀深度、干涉条纹取向和DMD输入图形的结构,系统能数字化完成2D/3D、3D光变图像、超微图形文字以及二元光学元件的制作,实现了超高分辨率图形与高效的干涉光刻.给出了实验结果.     

单模光纤相位光栅外腔主动锁模半导体激光器

报道用单模光纤光折变相位光栅作外腔的主动锁模半导体产激光器，产生１．５３μｍ，１．０６５ＧＨｚ，１５ｐｓ的近变换限超短光脉冲。     

基于SFRL的FWM型可调谐波长转换器啁啾特性分析

基于半导体光纤环形腔激光器的四波混频型可调谐全光波长转换器的宽带理论模型,从理论上研究了输入信号光功率、注入电流、两个耦合器的耦合比、激射光波长和半导体光放大器有源区长度对转换光频率啁啾的影响.结果表明:转换光的频率啁啾随着输入信号光峰值功率、注入电流以及SOA有源区长度的增大而增大,随两个耦合器耦合比的增大而减小.