On-Chip All-Optical Passive 3.55 Gbit/s NRZ-to-PRZ Format Conversion Using a High-Q Silicon-Based Microring Resonator

We report the experimental result of all-optical passive 3.55 Gbit/s non-return-to-zero (NRZ) to pseudo-return-to-zero (PRZ) format conversion using a high-quality-factor (Q-factor) silicon-based microring resonator notch filter on chip. The silicon-based microring resonator has 23800 Q-factor and 22 dB extinction ratio (ER), and the PRZ signals has about 108 ps width and 4.98 dB ER.

Analysis of directional emission in square resonator lasers with an output waveguide

Square microcavity laser with an output waveguide is proposed and analyzed by the finite-difference time-domain (FDTD) technique. For a square resonator with refractive index of 3.2, side length of 4 microns, and output waveguide of 0.4-micron width, we have got the quality factors (Q factors) of 6.7×10~2 and 7.3×10~3 for the fundamental and first-order transverse magnetic (TM) mode near the wavelength of 1.5 microns, respectively. The simulated intensity distribution for the first-order TM mode shows that the coupling efficiency in the waveguide reaches 53%. The numerical simulation shows that the first-order transverse modes have fairly high Q factor and high coupling efficiency to the output waveguide. Therefore the square resonator with an output waveguide is a promising candidate to realize single-mode directional emission microcavity lasers.

Potential light source for photonic integrated circuits based on the equilateral triangle resonator

The semiconductor microlasers based on the equilateral triangle resonator (ETR) can be fabricated from the edge-emitting laser wafer by dry-etching technique, and the directional emission can be obtained by connecting an output waveguide to one of the vertices of the ETR. We investigate the mode characteristics, especially the mode quality factor, for the ETR with imperfect vertices, which is inevitable in the real technique process. The numerical simulations show that the confined modes can still have a high quality factor in the ETR with imperfect vertices. We can expect that the microlasers is a suitable light source for photonic integrated circuits.

Eigenmode confinement in semiconductor microcavity lasers with an equilateral triangle resonator

We analyze the mode behaviors for semiconductor lasers with an equilateral triangle resonator by deriving the mode field distribution and the eigenvalue equation. The eigenvalue equation shows that the longitudinal mode wavelength interval is equivalent to that of a Fabry-Perot cavity with the cavity length of 1.5a, where a is the side length of the equilateral triangle resonator. The transverse waveguiding is equivalent to as a strip waveguide with the width of root 3a/ 2, and the number of transverse modes supported by the resonator is limited by the total reflection condition on the sides of the equilateral triangle. Semiconductor microcavity laser with an equilateral triangle resonator is suitable to realize single mode operation, and the mode wavelength can be adjusted by changing the side length.

A mica-modified quartz resonator for a quartz crystal microbalance study

Mica, as a bridge of the study for combining between quartz crystal microbalance (QCM) and atomic force microscope (AFM), was successfully modified onto the piezoelectric quartz crystal (PQC). This mica-modified piezoelectric quartz crystal (mica-PQC) can be stably oscillated with a shift frequency of +/-1 Hz per half an hour in air. Using this mica-PQC, the processes of DNA adsorbed onto the mica surface were studied in liquid phase. The results show that a bivalent cation, such as Mn2+, can be used as an ionic bridge to immobilize DNA on mica surface. The image of DNA on the mica surface was also obtained by AFM. Mica-PQC gives the possibility of a combination between QCM and AFM in situ.

Experimental investigation of an unstable ring resonator with 90-deg beam rotation for a chemical oxygen iodine laser

We report the experimental results of an unstable ring resonator with 90-deg beam rotation for a kilowatt class chemical oxygen iodine laser (COIL). The distributions of near-field phase and far-field intensity were measured. A beam quality of 1.6 was achieved when the COIL average output power was approximately 5 kW. (C) 1999 Optical Society of America.

Near-diffraction-limited, 35.4 W laser-diode end-pumped Nd:YVO4 slab laser operating at 1342 nm

A diode stack end-pumped Nd:YVO4 slab laser at 1342 nm with near-diffraction-limited beam quality by using a hybrid resonator was presented. At a pump power of 139.5 W, laser power of 35.4 W was obtained with a conversion efficiency of 25.4% of the laser diode to laser output. The beam quality M-2 factors were measured to be 1.2 in the unstable direction and 1.3 in the stable direction at the output power of 29 W. (C) 2009 Optical Society of America

溶胶-凝胶光波导环形谐振腔的挥发性有机化合物传感特性

采用溶胶-凝胶法制作波导环形谐振腔, 讨论了环形谐振腔器件的传输特性。测量了在不同物质、不同体积分数的挥发性有机化合物(VOC)蒸气气氛下器件的传输光谱的敏感性。结果表明, 谐振波长随甲醇、乙醇、丙醇等醇类化合物, 以及丙酮、甲醛等蒸气体积分数的上升而向长波方向移动, 具有高的灵敏度, 且两者基本呈线性关系。其中, 对丙醇最敏感, 灵敏度达到1.403 pm/10-6。对甲烷和二甲苯也有微弱反应, 但是其灵敏度很低。也测量了水蒸气对传输谱特性的影响。观察到传输谱衬比度对不同挥发性有机化合物物质蒸气的不同敏

一种新型结构的单纵模光纤激光器

单纵模掺铒光纤激光器在光通信和光传感等方面有着广泛的应用前景。设计了一种新型的光纤激光器，在光纤环形镜中嵌入未抽运的掺铒光纤作为可饱和吸收体以抑制多纵模，用光纤环谐振腔作为滤波器抑制拍频噪声，用光纤光栅作为波长选择器件，最终得到了单纵模输出并消除了拍频噪声。使用零拍法测量其线宽小于频谱仪的低频极限5kHz。实验结果证明了可饱和吸收体和光纤环的功能。

Characteristics of an add-drop filter composed of a Mach-Zehnder interferometer and double ring resonators

A planar lightwave circuit (PLC) add-drop filter is proposed and analyzed, which consists of a symmetric Mach-Zehnder interferometer (MZI) combined with double microring resonators. A critical coupling condition is derived for a better box-like drop spectrum. Comparisons of its characteristics with other schemes, such as a MZI with a single ring resonator, arepresented, and some of the issues about device design and fabrication are also discussed.

有源波导环形谐振腔滤波特性分析

将掺铒有源波导材料引入环形谐振腔结构，从理论上分析了有源波导环形谐振腔的滤波特性。结果表明由于抽运光提供的增益补偿了腔内损耗，使得环形谐振腔满足临界耦合条件，实现对信号光的最佳陷波，同时发现通过改变抽运光功率，可以对精细度和带宽进行动态调谐。分析了铒离子掺杂浓度、信号光功率以及抽运光耦合系数对最佳陷波抽运功率的影响，为有源波导器件设计制作提供了理论依据。

利用有机-无机溶胶-凝胶方法制备平面波导环形谐振腔

采用简单的有机一无机混合的溶胶一凝胶方法制备了折射率在一定范围内可调的波导材料，并利用其制备了平面波导环形谐振腔器件。波导结构呈现倒脊形，其制备工艺首先是利用感应耦合等离子体刻蚀技术（ICP）在二氧化硅衬底上刻蚀波导结构的凹槽，然后再沉积波导薄膜。利用光谱仪对器件的传输特性进行了测量，观测到具有10dB对比度，自由光谱范围0．182nm周期性谐振现象，结合环形谐振腔的传输特性，得到环形腔具有较低的传输损耗1．7dB／cm。同时对环形谐振腔的温度特性进行了测量，得出波导材料的热光系数为-1．54×10^-4

一种离子交换制备的玻璃光波导谐振腔滤波器

采用AgNO3、KNO3混和熔盐作为离子交换源，在K9玻璃上制备了跑道形谐振腔滤波器。测试得到该滤波器的自由光谱范围为0．178nm，两个输出端口的衬比度分别为1．47dB和6．5dB，分析得到耦合器的分束比和谐振腔的传输损耗分别为κ=0．16和α=8．1dB／cm。利用热光效应在16℃的温度变化范围内，滤波器实现了2π的相位调制，同时分析得到波导材料的热光系数约为1．28×10^-5／℃。

利用离子交换技术制备跑道形波导谐振腔滤波器的研究

采用AgNO3和KNO3混和熔盐作为离子交换源，在K9玻璃上制备了跑道形波导谐振腔滤波器。利用ASE宽带光源和光谱仪对器件特性进行了测试，得到的该滤波器自由光谱范围为0．176nm。对比对Cr=4dB和3dB带宽δλ=0.13nm来说，耦合系数和传输损耗分别为κ=0．9和α=3．2dB／cm。测试了环形腔的热光调相特性，在16℃的变化范围内实现了2π的相移。通过分析，波导材料的热光系数约为1．49×10^-5/C。该滤波器不仅可用于滤波、传感等领域，而且也可与其它波导结构相结合实现新的功能。