Cylindrical concave diffraction grating utilising thin silicon chip

A unique manufacturing method for concave diffraction gratings is proposed. Also, a cylindrical concave diffraction grating was manufactured with a multimode slab waveguide. A silicon plane diffraction grating was bent cylindrically in this method. The efficiency of the concave diffraction grating was 82% at a 1.3 ?m wavelength. The efficiency was about the same as that of the plane diffraction grating.     

External-cavity semiconductor laser with 15 nm continuous tuning range

A 1.26 ?m optical amplifier with a facet modal reflectivity below 0.0001 has been used in a 58 mm-long grating external cavity. The lasing wavelength has been continuously tuned without mode hopping over a range of 15 nm by combined translation-rotation of the diffraction grating. A linewidth of 20 kHz has been derived from heterodyne beat frequency measurements between two tunable external-cavity lasers.     

10 kHz linewidth 1.5 ?m InGaAsP external cavity laser with 55 nm tuning range

An InGaAsP 1.5 ?m laser, with one facet antireflection coated, has been incorporated into a diffraction grating external cavity. The lasing wavelength could be tuned over a 55 nm range about the centre wavelength of 1.5 ?m by rotating the grating. Furthermore, it was found that the emission spectrum was extremely narrow; beat-frequency measurements at 1523 nm against an HeNe laser showed it to be of the order of 10 kHz.     

Optical grating multiplexer in the 1.1?1.5 ?m wavelength region

Experimental results of a multiplexer using a diffraction grating for a wavelength-division-multiplexing transmission system are described. The multiplexer has 10 channels and a wavelength spacing of 36.2 nm in the 1.1?1.5 ?m wavelength region. Minimum insertion loss for each channel was less than 2.2 dB.     

Arrayed-waveguide grating for wavelength division multi/demultiplexer with nanometre resolution

A novel diffraction grating based on arrayed channel waveguides has been proposed for nanometre-spaced wavelength division multiplexing. A grating with a diffraction order of 20 has been fabricated using a composite glass waveguide. A wavelength resolution of 0.63 nm has been achieved in the 1.3 mu m wavelength band.<>     

Highly tunable Bragg gratings in single-mode polymer optical fibers

A Bragg grating in a single-mode polymer optical fiber (POF) has been created. The novel grating has a length of 1 cm with a reflectivity of 80% and a linewidth of about 0.5 nm. The wavelength tunability of the POF grating by stretching was investigated and a wavelength tunable range of 20 nm has been achieved. Based on the properties of the polymer, we believe that this kind of grating has a wavelength tuning potential of more than 100 nm     

光刻胶灰化技术用于同步辐射闪耀光栅制作

在分析光刻胶光栅浮雕图形缺陷成因的基础上,首次将光刻胶灰化工艺引入到全息－离子束刻蚀制作闪耀光栅工艺中,并成功地为国家同步辐射实验室光化学站制作了１２００１／ｍｍ,闪耀波长为１３０ｎｍ的锯齿槽形光栅。测试结果表明光刻胶灰化处理对制作大面积优质的光刻胶光栅非常有效和实用。     

线性斜边滤波器在光纤光栅传感系统中的应用

介绍线性斜边滤波器在光纤光栅传感系统中的应用，根据斜边滤波器波长解调方案的工作原理，主要介绍一种利用斜边滤波器的光纤光栅解调技术．实验采用1530／1550nm的斜边滤波器对单点光纤光栅应变和温度进行解调，结果表明该解调系统具有0．01nm的波长分辨力，该系统结构简单，易于解调．     

A wavelength division multiplexer based on plastic surfacerelief grating applied to local area communication network

A plastic surface-relief grating as a wavelength division multiplexer is designed and fabricated with the conventional mould pressing technique using the transmission-type fused quartz phase grating as mask pattern and polycarbonate as basal material.The experiment results show that in an optimizing process,the plastic surface-relief grating has the highest firstorder diffraction efficiency under adequate groove depth and incident angle,and can be used as the best optical path for wavelength division multiplexing(WDM).We also establish the experiment setup for testing the WDM performance of the plastic surface-relief grating based wavelength division multiplexer.The results show that the proposed wavelength division multiplexer has the high-stability temperature characteristics,the low insertion loss of less than 5 dB,the large isolation of greater than 20 dB,the low polarization-dependent loss(PDL) of less than 0.4 dB and the relatively steep pass-band characteristics.It is a WDM device with good performance,which can be applied in short distance communication.     

复增益耦合型取样光栅DFB激光器的设计制作与性能

A complex-coupled DFB Laser with sampled grating has been designed and fabricated. The key concepts of the approach are to utilize the +1st order reflection of the sampled grating for laser single mode operation, and use a conventional holographic exposure combined with the usual photolithography to fabricate the sampled grating. The typical threshold current of the sampled grating based DFB laser is 25mA, and the optical output is about 10mW at the injected current of 100mA. The lasing wavelength of the device is 1.5385μm, which is the +1st order wavelength of the sampled grating.     

Design and performance of a complex-coupled DFB laser with sampled grating

A complex-coupled DFB laser with sampled grating has been designed and fabricated. The method uses the + 1 st order reflection of the sampled grating for laser single-mode operation. The typical threshold current of the sampled grating based DFB laser is 25 mA, and the optical output is about 10 mW at the injected current of 100 mA. The lasing wavelength of the device is 1.5385μm, which is the +1 st order wavelength of the sampled grating.     

三角形谱啁啾光纤光栅在光栅传感系统中的应用

利用三角形谱啁啾光纤布拉格光栅（T-CFBG）的反射和时延特性，提出了一种新的基于相位检测的FBG解调方案。该方案由光强来确定传感器光栅反射波长的相位延迟角范围，由相位检测来确定在该范围的相位延迟角大小，两者结合给卅传感光栅的反射波长，因此具有更高精度和更大波长检测范围。实验制作了宽带宽具有三角形反射谱的T-CFBG，并对其用于传感解调予以了模拟分析。     

Modes in s.a.w. grating resonators

It is shown that s.a.w. gratings on the surface of an isotropic medium may support modes that are confined underneath the grating. The 3-dimensional resonant-mode patterns are derived for the Rayleigh wave in a high-Q-factor resonator consisting of two gratings separated by ?/2, where ? is the grating periodicity, in the limit when the grating width is large compared with a wavelength. The resonance frequencies of the different modes are presented.     

声光调Q CO2激光器波长调谐理论分析与实验研究

采用旋转光栅法实现了声光调Q CO2激光器可调谐脉冲激光输出。理论分析了CO2激光波长调谐特性,发现调节各支谱线腔内损耗是实现激光波长调谐的有效方法。进而理论计算了特定设计波长闪耀光栅的衍射效率与激光波长间的关系,结果显示光栅调谐的激光谱线自准直角与光栅闪耀角一致时具有最高的衍射效率。采用闪耀角分别为31.97（闪耀波长10.59 m）和28.71（闪耀波长9.60 m）的光栅实验研究了声光调Q CO2激光器波长调谐特性,分别获得了65条和75条激光谱线。实验结果显示:光栅设计闪耀波长处于弱激光增益分支时可获得更多条激光谱线,该实验与理论计算结果相符。在脉冲重复频率为1 kHz时,获得10.59 m激光脉冲宽度为160 ns,平均功率4.2 W,脉冲峰值功率26.25 kW,且稳定性良好。     

氧化锌单晶DFB半导体激光器的设计与分析

基于严格耦合波理论(RCWA)和介质平板波导理论,针对光通信中的1550 nm波长,设计了一种基于氧化锌(ZnO)单晶的分布反馈式(DFB)半导体激光器的光栅结构,分析了二维电场模式图以及激射波长线宽图,得到了光栅结构的变化对其单纵模传输的影响。仿真结果表明,当光栅的周期为489 nm,占空比为50%,光栅深度为400 nm时,全局电场能量达到了8.3×107 J,光谱线宽小于0.1 。该激光器具有很好的窄线宽输出以及波长选择特性。理论分析与仿真结果基本一致为后期进行该器件的制备提供了较好的参考。     

Active wavelength demodulation of Bragg fibre-optic strain sensorusing acousto-optic tunable filter

An acousto-optic tunable based active wavelength demodulation system for intracore Bragg grating fibre-optic sensors has been demonstrated. The system uses an intensity self-referenced edge-locking technique to track the reflected signal of the Bragg sensor. A strain resolution of 2.2 με was achieved with a Bragg fibre-optic strain sensor operating at ~1324 nm. Corresponding to a wavelength resolution of 2.6 pm. The potential for high resolution measurements over wide wavelength ranges is particularly attractive for wavelength multiplexing of Bragg grating sensors     

基于二维激光告警的闪耀光栅设计

现有光栅衍射型激光告警中,正弦光栅存在1级衍射效率较低,闪耀光栅在闪耀波长附近0级和-1级衍射效率很低,这两种光栅的缺点都降低了激光告警的可靠性。为此文中提出了一种改进型闪耀光栅。将两闪耀光栅反相对接,并且中间留一定无光栅空间,此改进可提高波长在闪耀波长附近0级和-1级的衍射效率,将有效克服传统闪耀光栅的漏报警现象。设计加工了闪耀波长为800 nm的改进型闪耀光栅,理论分析了0级和1级衍射效率;采用波长为808 nm和850 nm的光,对改进型闪耀光栅进行二维激光告警实验测试,实验结果表明,在波长为闪耀波长附近光入射时,改进型较普通闪耀光栅的0级和-1级衍射强度有很大提高,能够被CCD有效探测。该改进型闪耀光栅可有效提高二维激光告警系统的可靠性。     

探测波导全息光栅傅里叶变换光谱的新方法

提出一种利用波导全息光栅分光元件 ,通过测量波导光栅附近区干涉条纹 ,经快速傅里叶变换达到测量光谱的新方法。讨论了波长测量范围和光谱分辨率。给出了在设计波导光栅、确定探测器时应该考虑的几个问题。对系统测量误差进行了分析。该光谱探测方法具有光谱分辨率高、波长范围宽和结构简单等优点。     

基于光纤光栅级联调谐技术的波长检测系统

报道了一种检测光纤光栅传感器波长的新方案。实验系统采用新型的级联结构对电热调谐的光纤光栅滤波器进行复用,扫描分析传感信号光的峰值波长,同时用参考波长校准方法消除了电热调谐中的蠕动误差。结果表明,系统的检测范围可达23nm,波长分辨率为3.1pm,应变测量分辨率为2.56με。     

Athermalized Polymeric Arrayed‐Waveguide Grating by Partial Detachment from a Si Substrate

We demonstrate a new fabrication method for adjusting the temperature dependence of a polymeric arrayed‐waveguide grating (AWG) on a Si substrate. A temperature‐dependent wavelength shift of ?0.1 nm/°C in a polymeric AWG on a Si substrate is reduced to +0.01 nm/°C by detaching part of the polymer film, including the grating channel region of the AWG, from the Si substrate while the other parts remain fixed on the substrate.