Asymmetrical Fabry-Perot cavity slot micro-ring resonator and its sensing characteristics

To achieve high quality factor and high-sensitivity refractive index sensor,a slot micro-ring resonator(MRR)based on asymmetric Fabry-Perot(FP)cavity was proposed.The structure consisted of a pair of elliptical holes to form an FP cavity and a microring resonator.The two different optical modes generated by the micro-ring resonator were destructively interfered to form a Fano line shape,which improved the system sensitivity while obtaining a higher quality factor and extinction ratio.The transmission principle of the structure was analyzed by the transfer matrix method.The transmission spectrum and mode field distribution of the proposed structure were simulated by the finite difference time domain(FDTD)method,and the key structural parameters affecting the Fano line shape in the device were optimized.The simulation results show that the quality factor of the device reached 22037.1,and the extinction ratio was 23.9 dB.By analyzing the refractive index sensing characteristics,the sensitivity of the structure was 354 nm·RIU−1,and the detection limit of the sensitivity was 2×10−4 RIU.Thus,the proposed compact asymmetric FP cavity slot micro-ring resonator has obvious advantages in sensing applications owing to its excellent performance.

Highly sensitive digital optical sensor with large measurement range based on the dual-microring resonator with waveguide-coupled feedback

We propose a novel high-performance digital optical sensor based on the Mach-Zehnder interferential effect and the dual-microring resonators with the waveguide-coupled feedback. The simulation results show that the sensitivity of the sensor can be orders of magnitude higher than that of aconventional sensor, and high quality factor is not critical in it. Moreover, by optimizing the length of the feedback waveguide to be equal to the perimeter of the ring, the measurement range of the proposed sensor is twice as much as that of the conventional sensor in the weak coupling case.

A large bandwidth photonic delay line using passive cascaded silicon-on-insulator microring resonators

This paper investigated the design and the characterization of a photonic delay line based on passive cascaded silicon-on-insulator （SOI） microrings. We considered the compromise of group delay, bandwidth and insertion loss. A 3-stage double channel side-coupled integrated spaced sequence of resonator （SCISSOR） device was optimized by shifting the resonance of each microring and fabricated with electron beam lithography and dry etching. The group delay was measured to be 17 ps for non-return-to-zero signals at different bit rates and the bandwidth of 78 GHz was achieved. The experiment result agreed well with our simulation.

Design,fabrication and characterization of a high-performance microring resonator in silicon-on-insulator

A high-performance microring resonator in a silicon-on-insulator rib waveguide is realized by using the electron beam lithography followed by inductively coupled plasma etching. The design and the experimental realization of this device are presented in detail. In addition to improving relevant processes to minimize propagation loss, the coupling efficiency between the ring and the bus is carefully chosen to approach a critical coupling for high performance operating. We have measured a quality factor of 21,200 and an extinction ratio of 12.SdB at a resonant wavelength of 1549.32nm. Meanwhile, a low propagation loss of 0.89dB/mm in a curved waveguide with a bending radius of 40μm is demonstrated as well.

Modeling and analysis of silicon-on-insulator elliptical microring resonators for future high-density integrated photonic circuits

We propose a novel resonator containing an elliptical microring based on a silicon-on-insulator platform. Simu- lations using the three-dimensional finite-difference time-domain method show that the novel elliptical microring can efficiently enhance the mode coupling between straight bus waveguides and resonator waveguides or between adjacent resonators while preserving relatively high intrinsic quality factors with large free spectral range. The proposed resonator would be an alternative choice for future high-density integrated photonic circuits.

Bandwidth-tunable silicon nitride microring resonators

We designed a reconfigurable dual-interferometer coupled silicon nitride microring resonator.By tuning the integrated heater on interferometer's arms,the"critical coupling"bandwidth of resonant mode is continuously adjustable whose quality factor varies from 7.9×10^(4) to 1.9×10^(5) with the extinction ratio keeping higher than 25 dB.Also a variety of coupling spanning from"under-coupling"to"over-coupling"were achieved,showing the ability to tune the quality factor from 6.0×10^(3) to 2.3×10^(5).Our design can provide an adjustable filtering method on silicon nitride photonic chip and contribute to optimize the nonlinear process for quantum photonics and all-optical signal processing.

Bright 547-dimensional Hilbert-space entangled resource in 28-pair modes biphoton frequency comb from a reconfigurable silicon microring resonator

High-dimensional entanglement provides valuable resources for quantum technologies,including quantum communication,quantum optical coherence tomography,and quantum computing.Obtaining a high brightness and dimensional entanglement source has significant value.Here we utilize a tunable asymmetric Mach–Zehnder interferometer coupled silicon microring resonator with 100 GHz free spectral range to achieve this goal.With the strategy of the tunable coupler,the dynamical and extensive tuning range of quality factors of the microring can be obtained,and then the biphoton pair generation rate can be optimized.By selecting and characterizing 28 pairs from a more than 30-pair modes biphoton frequency comb,we obtain a Schmidt number of at least 23.4 and on-chip pair generation rate of 19.9 MHz/m W;under a low on-chip pump power,which corresponds to 547 dimensions Hilbert space in frequency freedom.These results will prompt the wide applications of quantum frequency comb and boost the further large density and scalable on-chip quantum information processing.

MZI wavelength interleaving filter based on double microring structure

To improve the output characteristics of all-fiber Mach-Zehnder interferometer(MZI)-interleaver,a dual microring-assisted MZI interleaver is designed.According to its structure,the output expression of the device is derived from the signal flow diagram.After simulation analysis,the optimal structural parameters during the transmission process are obtained.In addition,the coupling coefficient and transmission loss of the coupler are analyzed.The results show that the improved interleaver output line wave is closer to the square wave,and its 25 dB cutoff band bandwidth and 0.5 dB passband bandwidth are significantly improved,with the values of 41.2 GHz and 18.9 GHz,respectively.The device has a certain resistantability to deviation,and the transmission loss has less influence on the extinction characteristics of the filter.

基于光学微环谐振器的甲醛传感器模拟研究

针对在日常生活使用广泛但危害性极大的甲醛溶液,基于光学微环谐振器,设计了一种灵敏度高、动态范围大的折射率传感器,用来检测甲醛溶液浓度。本文利用波导微扰理论,确定了使系统灵敏度最大化的波导核心尺寸,利用有限元进行模拟计算。结果发现:利用该传感器如果检测到10^(-5)的相对波长位移,那么就可以检测到10^(-4)的相对折射率变化,并且通过包层去除方法还可进一步提升该传感器的灵敏度,与其他方法相比,这种甲醛溶液探测传感器的灵敏度有了很大程度的提升,对实际甲醛溶液的测量有着实际指导意义。

基于细粒度的光片上网络MRR制程漂移容错研究

光片上网络是片上网络发展的新方向,微环谐振器是光片上网络中的关键器件,然而由于微环谐振器对制程漂移较为敏感、极易发生故障,如何对制程漂移造成的微环谐振器故障进行容错是提高光片上网络可靠性的关键。针对该问题提出了一种细粒度的微环谐振器制程漂移容错方法,建立微环谐振器制程漂移模型,采用基于樽海鞘群算法的微环谐振器制程漂移容错方法,并结合多策略的冗余微环谐振器进行容错。实验结果证明,所提方法相比整数线性规划等方法,可以最高提高21%的带宽和减少66.7%的调整功耗,证明了所提方法的有效性。

光片上网络MRR故障检测方法研究

光片上网络(photonic network-on-chip,PNoC)是下一代片上网络互联的趋势和典范,MRR(microring resonator)是PNoC中的关键器件,然而由于制造缺陷,且MRR对温度波动高度敏感,MRR极易发生故障,如何检测MRR故障是十分重要并亟待解决的问题。针对该问题提出了一种基于故障检测图的MRR故障检测方法,将n端口的光路由器建模为完全加权有向图并且建立MRR故障模型,通过完全加权有向图与故障模拟,确定基于MRR故障模型和故障检测图的故障检测方法。实验结果证明,在单故障和双故障模拟下,该方法均能够获得满意的故障覆盖率。

实时双环谐振腔光谱包络拟合

双环级联谐振腔(Cascaded Microring Resonators,CMRR)传感器作为一种新型的光学传感器,因具有高灵敏度、易于集成、功耗小等优点被广泛应用于生物、医学等领域。为了实现CMRR传感器输出光谱的实时数据分析处理,提出了一种基于Python的实时CMRR传感器输出光谱包络拟合方法。首先,利用不同的拟合模型对CMRR传感器输出光谱进行拟合;然后,通过灵敏度误差百分比对不同拟合模型的拟合误差进行比较,结果显示平滑样条拟合法在实时处理CMRR传感器输出光谱过程中表现最佳;最后对不同浓度的NaCl溶液进行实时输出光谱采集处理,验证了CMRR传感器输出光谱实时采集处理程序的可靠性。实验结果表明CMRR传感器的波长漂移量与溶液浓度呈线性关系。通过计算可知CMRR传感器对于盐水的灵敏度约为671.03529 nm/RIU。

基于硅基微环谐振器的Fano共振线型产生和调谐研究进展

Fano共振的线型具有明显不对称特征,在光学通信、调制和传感等领域中极具应用潜力。首先对微环谐振器的各种线型进行了介绍,强调了Fano共振线型的独特优势,其次依据结构分类梳理了国内外基于硅基微环谐振器产生Fano共振的研究现状,然后介绍了基于热光效应的Fano共振调谐的研究进展,最后展望了硅基微环谐振器的Fano共振的发展及应用。

基于单个槽波导微环谐振器法诺共振的折射率传感

法诺线型的不对称和窄线宽特性有利于实现具有高传感灵敏度和低可探测极限的折射率传感。采用三维时域有限差分法,基于槽波导设计了微环谐振器和法布里-珀罗腔的耦合结构,实现了法诺线型谱线,并利用其提升折射率传感器的性能。不同于已报道的多微环级联等复杂结构,基于单个槽波导微环实现了法诺线型谱线,并在波长探测传感方案下得到传感灵敏度为500 nm/RIU,可探测极限为4.00×10^(-5) RIU;在强度探测传感方案下,传感灵敏度为7.24×10~4 dB/RIU,可探测极限为5.52×10^(-6) RIU。

Effects of manufacturing errors on the characteristics of a polymer vertical coupling microring resonator

The effects of manufacturing errors on transmission characteristics are analyzed for a polymer vertical coupling microring resonator.Calculated results show that the errors cause a shift and shape change of the transmission spectrum compared to the designed case without errors.Furthermore,accumulation and compensation for the errors is researched.In order to realize the normal filtering for the fabricated microring resonator device,some allowed errors are discussed.

Integrated reconfigurable optical add-drop multiplexers based on cascaded microring resonators

We report on an eight-channel reconfigurable optical add-drop multiplexer based on cascaded microring resonators with a high tuning power consumption and a compact footprint. Microheaters are fabricated on top of the microring resonators and can be modulated using the thermo-optic effect to achieve the reconfigurable functionality of the device. We demonstrate the reconfigurable add-drop multiplexing functionality for channel spacings of 1 O0 GHz and 50 GHz, with the centre wavelengths of the channels aligned to International Telecommunication Union grid specifications. The crosstalk for channel spacings of 100 GHz and 50 GHz are less than -22.5 dB and -15.5 dB, respectively. The average tuning efficiency is about 4.5 mW/nm, and the response speed is about 13.0 kHz.

Compact on-chip 1×2 wavelength selective switch based on silicon microring resonator with nested pairs of subrings

We propose and experimentally demonstrate compact on-chip 1×2 wavelength selective switches(WSSs) based on silicon microring resonators(MRRs) with nested pairs of subrings(NPSs). Owing to the resonance splitting induced by the inner NPSs, the proposed devices are capable of performing selective channel routing at certain resonance wavelengths of the outer MRRs. System demonstration of dynamic channel routing using fabricated devices with one and two NPSs is carried out for 10 Gb∕s non-return-to-zero signal. The experimental results verify the effectiveness of the fabricated devices as compact on-chip WSSs.

9.4 nm Tunable Vertically Coupled Microring Resonator Filter by Thermo-Optic Effect

A wide range (9.4nm) tuning of vertically coupled microring resonator filter was demonstrated utilizing a large TO coefficient of polymer. The power consumption was about 60m W and no degradation of filter response was observed.

Simultaneous measurement of refractive index and temperature using a microring resonator

An approach to the simultaneous optical ring resonators is proposed measurement of refractive-index （RI） and theoretically demonstrated. With and temperature changes using a liquid-core silica ring resonator as an example, two different-order whispering gallery modes （WGMs） might differ in not only RI but also temperature sensitivities. Thus, a second-order sensing matrix should be defined based on these WGMs to determine RI and temperature changes simultaneously. The analysis shows that the RI and temperature detection limits can be achieved on the order of 10.7 RI unit and 10-3 K at a wavelength of approximately 780 nm.

Generation rate scaling: the quality factor optimization of microring resonators for photon-pair sources

To achieve photon-pair generation scaling, we optimize the quality factor of microring resonators for efficient continuous-wave-pumped spontaneous four-wave mixing. Numerical studies indicate that a high intrinsic quality factor makes high pair rate and pair brightness possible, in which the maximums take place under overcoupling and critical-coupling conditions, respectively. We fabricate six all-pass-type microring resonator samples on a silicon-on-insulator chip involving gap width as the only degree of freedom. The signal count rate, pair brightness,and coincidence rate of all the samples are characterized, which are then compared with the modified simulations by taking the detector saturation and nonlinear loss into account. Being experimentally validated for the first time to the best of our knowledge, this work explicitly demonstrates that reducing the round-trip loss in a ring cavity and designing the corresponding optimized gap width are more effective to generate high-rate or high-brightness photon pairs than the conventional strategy of simply increasing the quality factor.