Microring Resonant Wavelength Research Articles

A single slot micro-ring structure for simultaneous CO2 and CH4 gas sensing

In this paper, we proposed a single silicon-on-insulator micro-ring structure for detecting two different gas components in the same time from one output spectrum. By introducing slot structure, the sensitivity and selectivity of sensor are improved. Specifically, two different sensing mechanisms are synthesized in this structure, thus output spectrum is impacted by varying concentrations of CH4 and CO2 respectively. The resonant wavelength of micro-ring resonator is the absorption peak of CH4, the concentration of CH4 can be measured with the light intensity change. Simultaneously, the combined action of CH4 and CO2 can cause the shift of resonant wavelength, and the total concentration of CH4 and CO2 gas can be obtained through the shift amount. For enhancing the evanescent field fraction in slot area and tuning the resonant wavelength of micro-ring being located on the absorption peak of CH4 (around 3.31 µm), the parameters of slot micro-ring structure, including height of slot in silicon, slot width, radius of micro-ring, waveguide width and the gap distance in coupling section, are well tailored, meanwhile, the quality factor Q of micro-ring is considered for ensuring a satisfied accuracy of sensor. A simulation based on the finite difference time domain method is implemented and the analysis results show that the sensitivity of sensor reaches 2308 nm/refractive index unit.

Actively stabilized silicon microrings with integrated surface-state-absorption photodetectors using a slope-detection method.

We propose and experimentally demonstrate actively stabilized silicon microrings with integrated surface-state-absorption (SSA) photodetectors using a slope-detection method. Our proof-of-concept experiments reveal that the active stabilization using multiple discrete-step slope thresholds can effectively reduce the microring transmitted intensity variations upon various temperature modulation conditions. We demonstrate an actively stabilized microring transmission with intensity modulations within ~2.5 dB upon a 5mHz temperature modulation between 17 °C and 31 °C, which is ~7.5dB improved from without stabilization. The active alignment tolerance between the stabilized microring resonance wavelength and a carrier wavelength is ~0.16 nm over a 14°C temperature modulation. We observe open eye-diagrams at a data transmission rate of up to 30 Gb/s under temperature modulations with actively stabilized silicon microrings.

Protein detection on biotin-derivatized polyallylamine by optical microring resonators.

Silicon optical microring resonators (MRRs) are sensitive devices that can be used for biosensing. We present a novel biosensing platform based on the application of polyelectrolyte (PE) layers on such MRRs. The top PE layer was covalently labeled with biotin to ensure binding sites for antibodies via a streptavidin-biotin binding scheme. Monitoring the shift in the microring resonance wavelength allows real-time, highly sensitive detection of the biomolecular interaction.

Extraction of a single Stokes line from a Brillouin fibre laser using a silicon oxynitride microring filter

Extraction of a single channel Brillouin Stokes line generated by pumping a length of single mode fibre is demonstrated using a silicon oxynitride microring resonator. The high Q-factor microring resonator has a steep slope transmission profile with an extinction ratio of 20 dB and a free spectral range of 0.4 nm. Experimental results show that extraction of a single Brillouin Stokes line can be achieved with a side mode suppression ratio of more than 12 dB. Additionally, Brillouin Stokes line selection can be achieved by controlling the microring resonance wavelength by thermal tuning.

Characterization of the evanescent field profile and bound mass sensitivity of a label-free silicon photonic microring resonator biosensing platform

Silicon photonic microring resonators have emerged as a sensitive and highly multiplexed platform for real-time biomolecule detection. Herein, we profile the evanescent decay of device sensitivity towards molecular binding as a function of distance from the microring surface. By growing multilayers of electrostatically bound polymers extending from the sensor surface, we are able to empirically determine that the evanescent field intensity is characterized by a 1/e response decay distance of 63 nm. We then applied this knowledge to study the growth of biomolecular assemblies consisting of alternating layers of biotinylated antibody and streptavidin, which follow a more complex growth pattern. Additionally, by monitoring the shift in microring resonance wavelength upon the deposition of a radioactively labeled protein, the mass sensitivity of the ring resonator platform was determined to be 14.7 ± 6.7 [pg/mm 2]/Δpm. By extrapolating to the instrument noise baseline, the mass/area limit of detection is found to be 1.5 ± 0.7 pg/mm 2. Taking the small surface area of the microring sensor into consideration, this value corresponds to an absolute mass detection limit of 125 ag (i.e. 0.8 zmol of IgG), demonstrating the remarkable sensitivity of this promising label-free biomolecular sensing platform.

Numerical analysis of a direct UV-written 1 × 8 double smooth octagon microrings resonant wavelength demulti/multiplexer

A microring resonant wavelength demulti/multiplexer (MRRWDM) based on UV-written technology is designed. By using a double smooth octagon microrings structure, a 1 × 8 device around the central wavelength of 1550.918 nm with the wavelength spacing of 1.4 nm is presented. Analytical results based on coupled mode theory show that the 3 dB bandwidth is about 0.22 nm, the insertion loss is less than 0.7 dB, and the crosstalk is below −47 dB for every output channel of the designed device without tolerances.

Analysis of a 1×32 polymer microring resonant wavelength de-multi/multiplexer assistant with interleave filter

A new 1×32 wavelength de-multi/multiplexer utilizing the microring resonator and interleave filter is proposed in this paper. A novel formula of transfer functions is presented, the parameters of microring are optimized, and the transmission characteristics of the system are analyzed. The channel spacing of the presented device is 0.4 nm. The analytical result shows that the crosstalk between adjacent channels can be reduced greatly and the filter response of the device can be improved by using the interleave filter. A bandwidth (3 dB) of 0.21 nm, an insertion loss less than 1.1 dB, and crosstalk below −32 dB were obtained for the optimized device. A method for compensating the manufacturing tolerances is discussed.

Simulation of 1×16 microring resonant wavelength multi/demultiplexer with triple vertically coupled microrings in every filter element

Novel formulas of the transfer functions and the amplitude coupling ratios are presented for characteristic analysis and parameter optimisation of a 1×16 microring resonant wavelength multi-/demultiplexer with triple vertically coupled rings in every filter element. This device can demultiplex 16 different wavelengths around the central wavelength of 1550 nm with the wavelength spacing of 0.8 nm. Simulation shows that by properly selecting the amplitude coupling ratios, the box-like flat spectral response can be formed and the crosstalk can be greatly reduced. The simulated results of the presented device are as follows: the 3 dB bandwidth is about 0.23 nm, the insertion loss is <0.7 dB and the crosstalk is below −50 dB for every vertical output channel. The birefringence caused by the polarisation dependence is about 1.7×10−4, which results in the wavelength shift of about 0.17 nm.

Characteristic Analysis of a Smooth Square Microring Resonant Wavelength Multiplexer

Novel formulas of amplitude coupling ratio and transmission functions are presented for a smooth square microring resonant (MRR) wavelength multiplexer. By using these formulas, transmission characteristics are analyzed and some parameters are optimized for such a 1 × 8 polymeric device around the central wavelength of 1550.92 nm with the wavelength spacing of 1.6 nm. In the design of the device, by using the smooth squares, a thicker coupling layer is obtained, and by resonating the light at different resonant orders in different filter elements, the ring radius increment is increased sufficiently, which is of benefit to the fabrication of the device. When the amplitude coupling ratio is 0.2, the 3-dB bandwidth of the spectral response is about 0.2 nm; the ratio between −1 dB and −10 dB bandwidths is about 0.2; the insertion loss is less than 1.33 dB; and the crosstalk is below −21 dB for every vertical output channel of the device.

Effect of bending on characteristics of a polymer microring resonant wavelength multiplexer

Novel formulas of transfer functions are presented, some parameters are optimized, and bending effect of microrings on characteristics is analyzed for a polymer microring resonant wavelength multiplexer (MRRWM) around the central resonant wavelength of 1.55 μm with the wavelength spacing of 1.6 nm and with eight vertical output channels. Simulated results show that the bending of microrings causes the variation of the propagation constant, leads to the shift of the transmission spectrum, and increases the insertion loss. A method is proposed for eliminating the shift of the transmission spectrum and realizing the accurate demultiplexing of the device. The polymer MRRWM designed possesses the 3-dB bandwidth of 0.2 μm, insertion loss less than 0.57 dB, and crosstalk below −20 dB for every vertical output channel.

Analysis of a 1 × 16 polymer microring resonant wavelength demulti/multiplexer with double seriated identical microrings in every filter element

Novel formulae of the amplitude coupling ratios and transfer functions are presented, parameter optimization is performed, transmission characteristics are analysed, and effects of manufacturing tolerances are investigated for a 1 × 16 polymer microring resonant wavelength demulti/multiplexer with double seriated rings in every filter element around the central wavelength of 1.55 µm with wavelength spacing 0.8 nm. Analytical results show that the 3 dB bandwidth is about 0.24 nm, the insertion loss is less than 0.77 dB, and the crosstalk loss is below −30 dB for every vertical output channel of the designed device without tolerances. The manufacturing tolerances cause a shift of the transmission spectrum and result in the increase of the crosstalk compared with the designed case without tolerances.

Optimization design and manufacturing tolerance analysis of a polymer microring resonant wavelength multiplexer

Based on formulas presented, optimization design is performed and the effects of manufacturing tolerances on transmission characteristics are analyzed for a polymer microring resonant wavelength multiplexer around the central wavelength of 1.550918 µm with wavelength spacing 1.6 nm. Modeling results show that the insertion loss is less than 0.55 dB and crosstalk is less than –21 dB for each of eight vertical output channels of the designed device without tolerances. Some manufacturing tolerances result in a shift of the transmission spectrum and lead to increases of the inserted loss and crosstalk over the design case without tolerances

Parameter optimization and characteristic analysis of a polymer microring resonant wavelength multiplexer

Novel formulas of transmission functions are presented, some parameters are optimized, and transmission characteristics are analyzed for a polymer microring resonant wavelength multiplexer around the central wavelength of 1.55 μm with the wavelength spacing of 5.6 nm and with eight vertical output channels. The computed results show that the designed device possesses some excellent features including the 3 dB bandwidth of 0.25 μm , weaker background light of 3.8×10 −4, smaller inserted loss of less than 0.6 dB , and lower crosstalk below −20 dB for every vertical output channel.