Integrated photonic glucose biosensor using a vertically coupled microring resonator in polymers

A photonic glucose biosensor incorporating a vertically coupled polymeric microring resonator was proposed and accomplished. The concentration of a glucose solution was estimated by observing the shift in the resonant wavelength of the resonator. For achieving higher sensitivity the contrast between the effective refractive index of the polymeric waveguide and that of the analyte was minimized. Actually, the effective refractive index of the polymeric waveguide (n = ∼1.390) was substantially close to that (n = ∼1.333) of the fresh solution with no glucose. The fabricated resonator sensor with the free spectral range of 0.66 nm yielded a sensitivity of ∼280 pm/(g/dL), which corresponds to ∼200 nm/RIU (refractive index units) as a refractometric sensor, and provided a detection limit of refractive index change on the order of 10⁻⁵ RIU.     

Proposal for a New Dense Wavelength Division Multiplexing Filter Based on Two-Dimensional Photonic Crystal Ring Resonator

Abstract

A new optical filter design based on a two-dimensional photonic crystal ring resonator structure with an N-channel model is proposed in this article. This study also shows that modifying the scatter radius and the waveguide width can significantly improve the performance of the original structure, which can solve the mode mismatch problem for output waveguide. Here, an example of a 16-channel photonic crystal ring resonator is provided; wavelength spacing of 1.6 nm and a high quality factor Q of 6,000 were achieved. The optical filter would be a potential key component in the application of dense wavelength division multiplexer devices.     

A compact plasmonic tunable filter using elasto-optic effects

We report on the theoretical concept of the design of a compact plasmonic tunable filter made of a metal–dielectric–metal waveguide and using elasto-optic effects. The proposed device is designed in a nanoring resonator structure and numerically studied by means of 3D-FEM simulations. We obtained an optimized nanoring resonator that has a radius R=390 nm and resonances at the telecommunication wavelength of 1.58 μm. Simulations using elasto-optic material as the dielectric layer and top and bottom Ag layers as electrodes indicate that the output can be tuned in the telecommunication wavelength range with an applied field. Further, using the proposed device, optical switching phenomenon is also found to be possible. This tunable ring resonator filter with ultra-small radii is considered valuable for photonic integrated systems.     

Analysis for amplifying characteristics of Er-Yb-co-doped microring resonators

Formulas of the transfer functions and the output power gains are presented, amplifying characteristics are analyzed, and simulation is performed for an Er³⁺-Yb³⁺-co-doped microring resonator. Under the pump wavelength of 980 nm and the central signal wavelength of 1550 nm, the dependence of the output power gain on the amplitude coupling ratio, pump power, signal power, and the dopant concentration is investigated, the output spectra are presented, and the optimization of the device is carried out. Simulated results show that the output power gain of this device is much larger than that of the Er³⁺-Yb³⁺-co-doped straight waveguide amplifier (EYCDWA) with the same waveguide parameters.     

一种新型可调制的光子晶体环形腔滤波器

在光子晶体环形腔中增加两个散射介质柱,构成一个新型的环形腔滤波器,该滤波器能有效选择光波透过,光波的透射率可以达到90%以上,带宽较小.可通过这两种不同的调节方式使滤波器中波长的带宽和数值进行任意的改变:1)减小散射介质柱半径,从负载波导输出波长的带宽变大,主波导中波长的带宽减小;增大其半径时,它们的变化正好相反.2)改变耦合区域介质柱半径的大小,滤波器中波长的数值也会相应地变化,它与介质柱半径的变化呈正比,并且透射率也会发生明显的变化.这就为其在制备集成光子器件的应用中奠定了基础. 关键词： 环形腔 滤波器 散射介质柱 透射率     

Low power Electro-optical filter: Constructed using silicon nanobeam resonator and PIN junction

In this paper, a high tunable Electro-optical filter is designed and simulated with low electric power consumption. A silicon nanobeam resonator based on one-dimensional photonic crystal in the form of Fabry–Perot structure, silicon-on-insulator waveguide, is proposed with a PIN junction. In designing nanobeam resonator, “deterministic design method” is used to achieve the high quality factor and high-transmission rate. Tuning of the resonant wavelength in the output channel of the filter is achieved by manipulating the refractive index of the active area by using the free-carrier dispersion effect. The output wavelengths of designed device can be tuned for the telecom-friendly 1.55 µm range. The device shows a wavelength shift higher than 3 nm for a power consumption of only 0.9 mW. Finally, the simulation results show that the provided device can be considered as a narrowband and tunable Electro-optical filter that is suitable for DWDM communication system.     

Amplifying Characteristics of Er3+/Yb3+ Co-Doped Parallel-Cascaded Double Microring Resonators

Abstract

In terms of the coupled mode theory, formulas of the transfer function and the output power gain are presented for an Er³⁺/Yb³⁺ co-doped parallel-cascaded double microring resonator. Around the pump wavelength of 0.98 μm and the central signal wavelength of 1.55 μm, analysis is performed for the dependence of the output power gain on the pump power, signal power, dopant concentration, amplitude coupling ratio, and ring spacing. The results show that the output power gain of this device is much larger than that of the Er³⁺/Yb³⁺ co-doped waveguide amplifier with identical waveguide lengths. In the case of the amplitude coupling ratio κ = 0.064, ring spacing L₂ = 10π R, pump power P_p0 = 8 mW, signal power P_s0 = 37.2 μW, Er³⁺ ion concentration N_Er = 1 × 26 m^?3, and Yb³⁺ ion concentration N_Yb = 3 × 27 m^?3, the device can produce higher signal power gain from 11.9 dB even up to 70 dB.     

温度测量范围加倍的单微环传感器

本文提出了一种基于U形波导耦合单微环结构的新型SOI(绝缘体上硅)温度传感器.温度变化引起感温部位有效折射率和长度变化,导致传感器的输出光谱发生漂移.根据传输矩阵法和耦合模理论,设计了新型传感器模型,并且分析了感温部位不同时系统输出光谱特性.结果表明:当U形波导耦合单微环整体结构感温时,输出光谱无伪模,消光比达到31 dB,可作为最佳感温元件.相比于传统的双直波导耦合单微环结构,当U形波导的两个耦合点间的距离为微环周长的整数倍数时,FSR(自由光谱范围)可加倍至56 nm,灵敏度提高到89.2 pm/?C,测量范围为298—720 K,实现了SOI微环谐振器的高温测量.     

基于十字连通形环形谐振腔金属-介质-金属波导的折射率传感器和滤波器

提出了由十字连通形环形谐振腔耦合两个金属-介质-金属(metal-insulator-metal, MIM)波导的结构,并用有限元法数值研究了表面等离极化激元在结构中的传输特性.通过对透射谱的研究,系统地分析了MIM结构的传感特性.结果表明,在透射光谱中有三个共振峰,即存在三种共振模式,其中透射峰与材料的折射率呈线性关系.通过对结构参数的优化,得到了折射率灵敏度(S)高达1500 nm/RIU的理论值,相应的传感分辨率为1.33×10~(-4)RIU.更重要的是,灵敏度不受结构参数变化的影响,这意味着传感器的灵敏度不受制造偏差的影响.此外,谐振波长与环形腔中心半径成线性关系,该器件在较大波长范围内实现可调谐带通滤波.透射强度随着波导与环形腔间距的增大而减小,透射带宽同时减小,因此,可以通过控制环形腔与波导的耦合距离来调谐透射强度及透射带宽.研究结果对高灵敏度纳米级折射率传感器和带通滤波器的设计以及在生物传感器方面的应用都具有一定的指导意义.     

平面环形谐振腔微光学陀螺结构设计与优化

提出具有高群有效折射率的双环级联作为核心元件的谐振式平面光波导陀螺结构, 基于光学Sagnac原理得到了双微环耦合谐振式光学陀螺理论灵敏度与群有效折射率的一般表达式和双环与单环陀螺系统的灵敏度关系, 并由耦合模理论方法得到了双环系统耦合器的两个透射系数对应的群有效折射率变化情况. 在环腔半径R₁=R₂=100 μm、环腔传输损耗系数t₁=t₂=0.95的情况下, 针对环与环之间耦合器和环与波导之间耦合器透射系数对群有效折射率的不同影响, 得到了最大群有效折射率的产生条件. 采用文中参数(R=100 μm, t=0.95)计算的单环谐振式陀螺灵敏度为(10⁴-10⁵)°/h, 而双环级联谐振系统理论灵敏度能够达到10 °/h. 该研究对微环耦合谐振腔在角速度检测上的应用有重要的意义.     

Design and optimization of photonic crystal based eight channel dense wavelength division multiplexing demultiplexer using conjugate radiant neural network

In this paper, two dimensional photonic crystal, based eight-channel demultiplexer is proposed and designed for DWDM applications. The performance parameters of the demultiplexer such as transmission efficiency, channel spacing, spectral line width, Q factor, and crosstalk have been evaluated. The proposed demultiplexer comprises of bus waveguide, drop waveguide and parellogram resonant cavity (PRC). The bus waveguide transmits light to the PRC and exits through respective drop waveguide. The PRC consists of a parellogram resonator with a nano ring cavity that is used for dropping eight specific wavelength for ITU-T G 694.1 standard with 50 GHz channel spacing. The circular ring resonator is placed above the PRC wherein a resonant air hole (Cr) is positioned for desired channel selection. The channel selection is done by altering the radius of the air hole. In addition, a conjugate radiant neural network is implemented for optimizing the radii of resonant air holes to select the required channel wavelength. The proposed device is very compact and it could be considered for implementing the photonic integrated circuits.     

Optimization of optical ring resonator devices for sensing applications

The Q-factor of an optical resonance device determines the width of its transmission resonances. For this reason, in sensing applications of optical resonators, it is commonly assumed that the Q-factor fully determines resonator sensitivity. Practically, the latter is not exactly correct. In this Letter, the parameters responsible for the sensitivity of resonance devices (i.e., the steepness and the sharpness of the transmission resonance) are analyzed. It is shown that, for given intrinsic losses of a single ring resonator sensor, the slope of the resonance is largest if its extinction ratio is 9.5 dB, while the resonance is sharpest if its extinction ratio is 6 dB. For a sensor consisting of several identical ring resonators coupled to a bus waveguide, the largest slope and sharpness parameters correspond to the extinction ratios of ~9 dB and ~4.5 dB, respectively. The determined optimum parameters can be achieved by tuning the coupling between the resonator rings and the waveguide.     

A new soliton communication band for optical networking redundancy using a Gaussian soliton generation

We present a novel communication band of the tunable multi-Gaussian soliton system, whereas the large bandwidth signals of the spatial soliton pulses can be generated after propagating within the nonlinear ring resonator system. A Gaussian pulse input with 20 ns pulse width, 2 W peak power, the center wavelength at 1300 nm is propagated into the nonlinear ring resonator system. Using the appropriate parameters relating to the practical device such as micro-ring radii, coupling coefficients, linear and nonlinear refractive index, we found that the multi-soliton pulse obtained have shown the potential of application for a new dense wavelength division multiplexing (DWDM) band. The soliton pulse width and free spectrum range of 400 and 7 fm are obtained, respectively, which can be used to increase the channel capacity in soliton communication. Furthermore, the soliton power obtained is available for system and link redundancy, where the output soliton power of 12 W is achieved.     

Vernier-cascade label-free biosensor with integrated arrayed waveguide grating for wavelength interrogation with low-cost broadband source

Recently, cheap silicon-on-insulator label-free biosensors have been demonstrated that allow fast and accurate quantitative detection of biologically relevant molecules for applications in medical diagnostics and drug development. However, whereas the sensor chip can be made cheaply, an expensive tunable laser is typically required to accurately monitor spectral shifts in the sensor's transmission spectrum (wavelength interrogation). To address this issue, we integrated a very sensitive Vernier-cascade sensor with an arrayed waveguide grating spectral filter that divides the sensor's transmission spectrum in multiple wavelength channels and transmits them to spatially separated output ports, allowing wavelength interrogation with a much cheaper broadband light source. Experiments show that this sensor can monitor refractive index changes of watery solutions in real time with a detection limit (1.6·10(-5)?RIU) competitive with more expensive interrogation schemes, indicating its applicability in low-cost label-free biosensing. The relaxation on the complexity of the source, moreover, offers the prospect to integrate the source and detectors to further reduce the device cost and to increase its portability.     

光子晶体环形谐振腔异质结构超微多路光分束器

基于直波导和环形谐振腔的耦合特性,设计了一种新型、高效的二维光子晶体异质结构光分束器.时域有限差分法模拟表明,该设计仅仅通过改变介质柱的折射率,使光场发生重新分布,便可实现输出能量的均分或自由分配.在通信波长范围,该设计结构尺寸小、分束角度大、分束率高,这些特性使其在光通信领域具有重要的应用前景.     

An integrated optical sensor for measuring glucose concentration

We used an optical sensor combined with a Mach-Zehnder interferometric waveguide and optical fibers to measure slight changes of aqueous sugar concentrations. The merits of this sensor are simplicity, reliability, high sensitivity and continuous monitoring. The technique is based on the fact that the refractive index of sugar solution changes with the concentration of sugar. In the experiment, one arm of the interferometer is clad with glue and is thus isolated from the sugar solution. The other one is exposed to the sugar solution. A single mode fiber is directly glued onto the interferometric waveguide, to guide the light into the interferometer. If the concentration of sugar covering the waveguide changes, the phase of propagating light in the exposed arm will be changed, while the phase in the other arm is fixed. Hence the output intensity from the interferometer is directly related to the concentration of the sugar solution. The result of this experiment yields the relation between the sugar concentration and output signal. From 0% to 1% concentration of sugar solution, there is only a 1.4×10^–3 refractive index difference. Two sets of experimental data have been obtained, showing a linear relation between the sugar concentration and the output signal from our sensor. This sensor could be used for continuous monitoring of blood sugar in the human body.     

A large-size SiO2 waveguide resonator used in integration optical gyroscope

We report on the resonance characteristics of a Si-based ring resonator model with the theory of multiple-beam interference. The resonator consists of a track pattern ring channel waveguides with radius of 2 cm, two input/output directional couplers and one ring resonator coupler. Using the wide angle finite-difference beam propagation method (WA-FDBPM), we presented optimal design of ring resonator and succeed in fabricating the ring resonator by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. Observed from the resonance curve, finesse of 16.7 is measured. And a rate detection limit of 1.7°/h can be evaluated.     

串联双微环湿度传感器光谱特性研究

提出了一种基于串联双微环谐振器的新型聚酰亚胺(Polyimide,PI)湿度传感器,采用传输矩阵法和耦合模的理论计算微环谐振器的传递函数,并对比了传统单微环与串联不同半径的双微环的输出光谱特性。外界湿度变化使得聚酰亚胺SOI波导吸收水汽后折射率发生变化,从而引起微环输出光谱发生漂移,通过探测光谱漂移量来测湿度值,得到了串联双微环传感器的灵敏度和测量范围,并且分析了感湿部位不同时谐振器输出光谱特性。理论结果表明：串联不同半径的微环谐振器的自由光谱范围（FSR）要比单微环有所提高,而且串联双微环谐振器整体感湿比单个微环单独感湿的传感性能更优良,可作为最佳的湿敏元件。与传统的单微环传感器相比,串联不同半径的微环结构可提高系统的测量范围和灵敏度,半径为30和50 μm的串联微环谐振器的FSR可达到0.15 μm,传感器测量湿度范围为10%RH～80%RH,灵敏度可达到0.001 7 μm·(%RH)-1。因此串联不同半径的双微环谐振器为制备成本低、结构简单、高灵敏度、可集成的微型湿度传感器件提供一定理论基础。     

High sensitivity and ultra-compact optical biosensor for detection of UREA concentration

In this paper, we suggest two-dimensional photonic crystal based biosensors for measurement of urea concentration in urine by means of refractive index detecting. In case of variation of urea concentration in urine, both the output peak intensity and the resonant peak center wavelength will shift. Two different structure dimensions are used to analyze the sensing characteristics of urine. The first sensor consists of a novel square ring joined to a simple waveguide with rods in air configuration. The second sensor is schemed by use of two-dimensional photonic crystals based on air hole in slab with elliptical resonant cavity in the middle of a photonic crystal waveguide. To realize sensing in both cases, we fill air area by urine sample. A high sensitivity is observed in small structures. In addition, we demonstrated a high quality factor, which is superior to those reported in recently published work discussing urine components based on photonic crystal, with small size sensors and fast response times.     

Proposal of the nano-sensing device and system using a nano-waveguide transducer for distributed sensors

We propose a new concept of a distributed sensing system using a nano-waveguide and an array waveguide. The small change in physical quantity affects the change in device parameters such as refractive index or length, which is relatively absorbed and observed by the resonant wavelength. In principle, the dense wavelength separation is generated by using a soliton pulse propagating within a ring resonator system, whereas a resonant signal can be stored within the nano-waveguide, i.e. a transducer, which is formed by the sensing device. Induced change in the resonant signal at each wavelength occurs, and can be detected by using the optical spectrum analyzer. Such a proposed device is suitable to perform the measurements in the nano-scale regime such as force, stress and temperature. Moreover, the distributed or multiplexed sensing applications are also available using the nano-waveguide sensing device incorporating the array waveguide, which is discussed in details. Quantum measurement using the same system is also described.