- 标题
- 摘要
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- 实验方案
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The Hollow Core Light cage: Trapping Light Behind Bars
摘要： Optical waveguides represent the key element of integrated planar photonic circuitry having revolutionized many fields of photonics ranging from telecommunications, medicine, environmental science and light generation. However, the use of solid cores imposes limitations on applications demanding strong light-matter interaction within low permittivity media such as gases or liquids, which has triggered substantial interest towards hollow core waveguides. Here, we introduce the concept of an on-chip hollow core light cage that consists of free standing arrays of cylindrical dielectric strands around a central hollow core implemented using 3D nanoprinting. The cage operates by an anti-resonant guidance effect and exhibits extraordinary properties such as (1) diffractionless propagation in “quasi-air” over more than a centimetre distance within the ultraviolet, visible and near-infrared spectral domains, (2) unique side-wise direct access to the hollow core via open spaces between the strands speeding up gas diffusion times by at least a factor of 104, and (3) an extraordinary high fraction of modal fields in the hollow section (> 99.9%). With these properties, the light cage can overcome the limitations of current planar hollow core waveguide technology, allowing unprecedented future on-chip applications within quantum technology, ultrafast spectroscopy, bioanalytics, acousto-optics, optofluidics and nonlinear optics.
关键词： integrated photonics,anti-resonance guidance,leaky modes,Hollow core waveguide,3D nanoprinting,spectroscopy
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Photonics Conference (IPC) - Reston, VA (2018.9.30-2018.10.4)] 2018 IEEE Photonics Conference (IPC) - 40Gb/s Carrier Depletion-Based Silicon Micro-Ring Modulators
摘要： A high-speed silicon microring modulator based on a titanium-doped silicon rib waveguide has been demonstrated. Small footprint of 26.5 μm × 26.5 μm with low driving voltage of 1.5 V and 22 dB extinction ratio at 20 Gb/s modulation has been achieved. The high-speed performance is attributed to the low capacitance of the device and the efficient plasma dispersion effect in silicon. Moreover, the modulator exhibits a low propagation loss of 2.5 dB/cm and a high modulation efficiency of 1.5 V·cm. The device is fabricated on a silicon-on-insulator (SOI) wafer with a 220 nm top silicon layer and a 2 μm buried oxide layer. The rib waveguide has a width of 500 nm and a height of 220 nm with a slab height of 150 nm. The titanium doping concentration is 1×10^20 cm^{-3}. The modulator is characterized using a lightwave component analyzer and a high-speed photodetector. The 3-dB bandwidth is measured to be 20 GHz. The eye diagrams at 20 Gb/s show clear eye opening with low jitter. The results indicate that the titanium-doped silicon microring modulator is promising for high-speed optical interconnects.
关键词： high-speed modulation,titanium doping,optical interconnects,silicon photonics,microring modulator
更新于2025-09-23 15:23:52
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Conditions for Parametric and Free-Carrier Oscillation in Silicon Ring Cavities
摘要： We model optical parametric oscillation in ring cavities with two-photon absorption, focusing on silicon at 1.55 μm. Oscillation is possible if free-carrier absorption can be mitigated; this can be achieved using carrier sweep-out in a reverse-biased p-i-n junction to reduce the carrier lifetime. By varying the pump power, detuning, and reverse-bias voltage, it is possible to generate frequency combs in cavities with both normal and anomalous dispersion at a wide range of wavelengths including 1.55 μm. Furthermore, a free-carrier self-pulsing instability leads to rich dynamics when the carrier lifetime is sufficiently long.
关键词： nonlinear optics,Frequency comb,silicon photonics
更新于2025-09-23 15:23:52
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Performances of Microwave Photonic Notch Filter Based on Microring Resonator with Dual-drive Modulator
摘要： A tunable microwave photonic notch ?lter with ultrahigh radio frequency (RF) rejection ratio is achieved by using a dual-drive Mach–Zender modulator and a microring resonator. In addition, we dedicated to clarify the mechanisms of the microwave photonic notch ?lters based on a microring resonator under both overcoupled and undercoupled states and the performance differences between these two situations are investigated in detail. Furthermore, the experimental results show that the cancellation microwave photonic notch ?lter with ultrahigh RF rejection ratio can be achieved with both undercoupled and overcoupled microring resonators. Besides, an RF rejection ratio exceeding 50 dB was achieved for a microring resonator with an optical extinction ratio of only 4 dB, where a 46-dB enhancement from optical to RF response is obtained. Also, the bandwidth of the microwave photonic ?lter can tuned from 0.65 to 2.2 GHz by adjusting the coupling ratio of the ring resonator. Meanwhile, by tuning the wavelength of the optical carrier, the ?ltering frequency can be tuned and a tuning range of about 25 GHz was achieved. The implementation is much simpler and more economical compared with previous reports and has great potential in monolithic integration of microwave photonic ?lters on chip.
关键词： Optical ?lter,Microwave photonics,Microring resonator,Integrated optics devices
更新于2025-09-23 15:23:52
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Multi-channel silicon photonic receiver based on compact second-order microring resonators
摘要： A monolithically integrated multi-channel receiver fabricated on the Silicon-on-Insulator (SOI) platform is demonstrated experimentally. This receiver is composed of an eight-channel thermally tunable microring resonator (MRR) filter as the wavelength division multiplexing (WDM) demultiplexer and an array of high speed waveguide-integrated Ge-on-Si photodetectors (PDs) for light detection. Second-order MRRs were utilized in each channel to obtain steeper roll-off from passband to stopband and lower crosstalk. The receiver was fabricated by using CMOS-compatible fabrication process at IME A*STAR. With the thermal tunability, the channel spacing can be adjusted according to different channel grid. Lower than ?30 dB crosstalk and higher than 50 GHz 3-dB bandwidth was obtained for the demultiplexer with a channel spacing of 150 GHz. Proof-of-principle demonstration shows that each channel is capable of operating at a data rate of 10 Gb/s, resulting in an aggregate data rate of 80 Gb/s.
关键词： Silicon photonics,Wavelength division multiplexing,Optical receivers,Microring resonators,Optical interconnects
更新于2025-09-23 15:23:52
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Ripple Suppression in Broadband Microwave Photonic Phase Shifter Frequency Response
摘要： This paper presents a detailed investigation on the cause of ripples in the frequency response of a microwave photonic phase shifter implemented using a 90° hybrid coupler. It was found that an unwanted radio frequency (RF) modulation sideband is generated at the modulator output due to the 90° hybrid coupler amplitude and phase imbalance. This resulted in phase shifter output RF signal amplitude variation and phase deviation. Experimental results demonstrated that incorporating an optical filter in the phase shifter structure can reduce the amplitude variation and phase deviation from 4.2 dB to 2.2 dB and from ±12° to ±3.8°, respectively, over a wide frequency range. A comparison of the loss and the dynamic range of the microwave photonic phase shifter implemented using a 90° hybrid coupler with a conventional fiber optic link is also presented.
关键词： phase shifters,microwave photonics,optical signal processing
更新于2025-09-23 15:23:52
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Enhanced Second Harmonic Generation from Ferroelectric HfO <sub/>2</sub> -Based Hybrid Metasurfaces
摘要： Integrated nonlinear metasurfaces leading to high-efficiency optical second harmonic generation (SHG) are highly desirable for optical sensing, imaging, and quantum photonic systems. Compared to traditional metal-only metasurfaces, their hybrid counterparts, where a non-centrosymmetric nonlinear photonic material is incorporated in the near field of a metasurface, they can significantly boost SHG efficiency. However, it is difficult to integrate such devices on-chip due to material incompatibilities, thickness scaling challenges and the narrow band gaps of nonlinear optical materials. Here, we demonstrate significantly enhanced SHG in on-chip integrated metasurfaces by using nanometer thin films of ferroelectric Y:HfO2. This material has the merit of CMOS compatibility, ultra-violet transparency up to 250 nm and significant scalability down to sub 10 nm when deposited on silicon. We observe a twenty times magnitude enhancement of the SHG intensity from the hybrid metasurface compared to a bare ferroelectric HfO2 thin film. Moreover, a 3-fold SHG enhancement is observed from the hybrid metasurface compared to a control structure using non-ferroelectric HfO2, demonstrating a major contribution to the SHG signal from ferroelectric Y:HfO2. The effective second-order nonlinear optical coefficient χ(2) of Y:HfO2 is determined to be 6.0 ± 0.5 pm/V, which is comparable to other complex nonlinear photonic oxide materials. Our work provides a general pathway to build an efficient on-chip nanophotonic nonlinear light source for SHG using ferroelectric HfO2 thin films.
关键词： second harmonic generation (SHG),nonlinear photonics,metasurface,plasmonics,ferroelectric Y:HfO2
更新于2025-09-23 15:23:52
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Microwave Photonic Signal Processing and Sensing Based on Optical Filtering
摘要： Microwave photonics, based on optical filtering techniques, are attractive for wideband signal processing and high-performance sensing applications, since it brings significant benefits to the fields by overcoming inherent limitations in electronic approaches and by providing immunity to electromagnetic interference. Recent developments in optical filtering based microwave photonics techniques are presented in this paper. We present single sideband modulation schemes to eliminate dispersion induced power fading in microwave optical links and to provide high-resolution spectral characterization functions, single passband microwave photonic filters to address the challenges of eliminating the spectral periodicity in microwave photonic signal processors, and review the approaches for high-performance sensing through implementing microwave photonics filters or optoelectronic oscillators to enhance measurement resolution.
关键词： Microwave photonics,photonic filtering,photonic signal processing,single sideband modulation,single passband microwave photonic filter,optical sensors
更新于2025-09-23 15:23:52
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Design of a C-band polarization rotator-splitter based on a mode-evolution structure and an asymmetric directional coupler
摘要： A C-band polarization rotator-splitter based on a mode-evolution structure and an asymmetric directional coupler is proposed. The mode-evolution structure is designed in a bi-level taper through which the TM0 mode can evolve into the TE1 mode. Then the TE1 mode is coupled to the TE0 mode at the cross port using the asymmetric directional coupler. The input TE0 mode propagates along the waveguide without mode conversion and output at the through port. From the experimental results, the extinction ratio is lower than 30 dB and the excess loss is less than 1 dB for input TE0 mode at the whole C-band. For input TM0 mode, the ER and the EL are, respectively, lower than ?10 and 1.5 dB.
关键词： silicon photonics,integrated optic devices,polarization rotator splitters
更新于2025-09-23 15:23:52
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Instantaneous microwave frequency measurement with high-resolution based on stimulated Brillouin scattering
摘要： A novel photonic method of instantaneous microwave frequency measurement (IMFM) based on Stimulated Brillouin scattering (SBS) is proposed. The principle of the technique is the employment of SBS effect to amplify/attenuate two adjacent frequency components, which result in a definite amplitude comparison function (ACF). Using this technique, the frequency of an unknown RF signal can be precisely obtained. Experimental results show the measurement capability of the proposed method over a frequency range of 0.47–23 GHz with a higher resolution of 8 MHz.
关键词： Amplitude comparison functions,Microwave photonics,Instantaneous microwave frequency measurement,Stimulated Brillouin scattering
更新于2025-09-23 15:23:52