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APL Photonics
Number of Followers: 1  Open Access journalISSN (Online) 2378-0967 Published by AIP  [28 journals]
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- Propagation of broadband mid-infrared optical pulses in atmosphere
First page: 080801
Abstract: We study and describe the reshaping of ultrashort and broadband mid-IR optical pulses in an ambient atmosphere. While all pulse propagation undergoes dispersion and absorption, which causes pulse reshaping, the effects are strongly pronounced for broadband radiation in the mid-IR due to the orders of magnitude greater oscillator strengths of molecular constituents of our atmosphere. A noticeable macroscopic impact is a transition of the measured autocorrelation function from squared hyperbolic secant to Lorentzian, which we fully explain based on pulse propagation, including molecular free induction decay. Electro-optical sampling directly reveals the light wave response to atmospheric molecular free induction decay, and a Kramers–Kronig-based propagation model thoroughly explains the observation. The findings are essential for applications in sensing, standoff detection, high-energy pulse propagation, and energy delivery.
PubDate: Tue, 06 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0218225
Issue No: Vol. 9, No. 8 (2024)
- On-chip mid-infrared dispersive wave generation at targeted molecular
absorption wavelengths
First page: 080802
Abstract: The mid-infrared wavelength region is one of the most important spectral ranges for a variety of applications in monitoring and controlling molecules due to the presence of strong characteristic absorption modes of many molecules. Among various mid-infrared light sources, on-chip supercontinuum sources have garnered significant attention for their high spatial coherence, broad spectral bandwidth, compact size, and dispersion controllability. However, generating a supercontinuum that extends into the molecular fingerprint region typically requires high-energy mid-infrared pump pulses from complex optical systems. In contrast, supercontinuum generated with 1550 nm pump sources, which are generally more compact, has shown limited access to the molecular fingerprint region. In this study, we developed an on-chip supercontinuum source with a dispersive wave generated at a targeted wavelength of up to 4800 nm using a coupled pump energy of about 25 pJ. The pump pulses at a wavelength of 2340 nm were generated from a relatively compact Cr:ZnS laser oscillator. The wavelengths of the generated dispersive waves closely matched the numerically predicted wavelengths. To demonstrate the applicability of the generated dispersive waves for spectroscopic purposes, molecular absorption spectroscopy was performed on the fundamental vibrational modes of 12CO2, 13CO2, and N2O. In addition, their pressures were quantitatively estimated using cepstrum analysis on the measured absorption spectra. The uncertainty in the measured pressure was close to the theoretical limit determined by the uncertainties in the absorption line shape parameters in the HITRAN database, demonstrating the potential of this mid-infrared light source for advanced spectroscopic applications.
PubDate: Thu, 22 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0221176
Issue No: Vol. 9, No. 8 (2024)
- Mid-infrared silicon photonics: From benchtop to real-world applications
First page: 080901
Abstract: Silicon photonics is one of the most dynamic fields within photonics, and it has seen huge progress in the last 20 years, addressing applications in data centers, autonomous cars, and sensing. It is mostly focused on the telecommunications wavelength range (1.3 and 1.55 µm), where silicon becomes transparent. In this range, there are excellent light sources and photodetectors, as well as optical fibers operating with extremely low losses and dispersion. It is a technology that hugely benefits from the availability of complementary metal–oxide–semiconductor (CMOS) fabrication infrastructure and techniques used for microelectronics. Silicon and germanium, as another CMOS compatible group IV material, are transparent beyond the wavelength of 2 µm. The mid-IR wavelength range (2–20 µm) is of particular importance as it contains strong absorption signatures of many molecules. Therefore, Si- and Ge-based platforms open up the possibility of small and cost-effective sensing in the fingerprint region for medical and environmental monitoring. In this paper, we discuss the current mid-IR silicon photonics landscape, future directions, and potential applications of the field.
PubDate: Fri, 16 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0222890
Issue No: Vol. 9, No. 8 (2024)
- AI-driven photonics: Unleashing the power of AI to disrupt the future of
photonics
First page: 080902
Abstract: Recent advances in artificial intelligence (AI) and computing technologies are currently disrupting the modeling and design paradigms in photonics. In this work, we present our perspective on the utilization of current AI models for photonic device modeling and design. Initially, through the physics-informed neural networks (PINNs) framework, we embark on the task of modal analysis, offering a unique neural networks-based solver and utilizing it to predict propagating modes and their corresponding effective indices for slab waveguides. We compare our model’s predictions against theoretical benchmarks and a finite differences solver. Evidently, using 349 analysis points, the PINN approach had a relative percentage error of 0.69272% compared to the finite differences method, which had a percentage error of 1.28142% with respect to the analytical solution, indicating that the PINN approach was more accurate in conducting modal analysis. Our model’s continuity over the entire solution domain enhances its performance and flexibility while requiring no training data due to its guidance by Maxwell’s equations, setting it apart from most AI approaches. Our model design also flexibly enables simultaneous prediction of multiple modes over any specified intervals of effective indices. In addition, we present a novel reinforcement learning (RL)-based paradigm, employing an actor–critic model for inverse design. We utilize this paradigm to optimize the transmittance of a grating coupler by manipulating the device geometry. Comparing the obtained design to that obtained using the Particle Swarm Optimization (PSO) algorithm, our RL-based approach effectively produced a significant enhancement of 34% in 14 iterations only over the initial design compared to the PSO, which prematurely scored 27% enhancement in 30 iterations, proving that our model navigates the design space more efficiently, achieving a better design than PSO and resulting in a superior design. Based on these approaches, we discuss the future of AI in photonics in forward modeling and inverse design and the untapped potential in bringing these worlds together.
PubDate: Tue, 20 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0220766
Issue No: Vol. 9, No. 8 (2024)
- Digital signal processing techniques for noise characterization of lasers
and optical frequency combs: A tutorial
First page: 081101
Abstract: Performing noise characterizations of lasers and optical frequency combs on sampled data offers numerous advantages compared to analog measurement techniques. One of the main advantages is that the measurement setup is greatly simplified. Only a balanced detector followed by an analog-to-digital converter is needed, allowing all the complexity to be moved to the digital domain. Secondly, near-optimal phase estimators are efficiently implementable, providing accurate phase noise estimation in the presence of measurement noise. Finally, joint processing of multiple comb lines is feasible, enabling the computation of the phase noise correlation matrix, which includes all information about the phase noise of the optical frequency comb. This tutorial introduces a framework based on digital signal processing for phase noise characterization of lasers and optical frequency combs. The framework is based on the extended Kalman filter (EKF) and automatic differentiation. The EKF is a near-optimal estimator of the optical phase in the presence of measurement noise, making it very suitable for phase noise measurements. Automatic differentiation is key to efficiently optimizing many parameters entering the EKF framework. More specifically, the combination of EKF and automatic differentiation enables the efficient optimization of phase noise measurement for optical frequency combs with arbitrarily complex noise dynamics that may include many free parameters. We show the framework’s efficacy through simulations and experimental data, showcasing its application across various comb types and in dual-comb measurements, highlighting its accuracy and versatility. Finally, we discuss its capability for digital phase noise compensation, which is highly relevant to free-running dual-comb spectroscopy applications.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0212592
Issue No: Vol. 9, No. 8 (2024)
- Structural color in fruits: Biomaterials to inspire physical optics
First page: 081102
Abstract: This Tutorial introduces structural color in fruits as a phenomenon of diverse optical materials. Originally best known in abiotic materials and animals, structural colors are being increasingly described in plants. Structural colors have already inspired a variety of useful products, and plants are especially attractive as models to develop new bioinspired technologies thanks to the comparative ease of working with them compared with animal systems. Already, human-engineered structural colors modeled after plant cellulose-based architectures have shown promising applications in colorants and sensors. However, structural colors include a far broader group of materials and architectures beyond cellulose. Understanding the new and diverse structures that have recently been described in plants should provoke research into new bioinspired products based on plant optical structures and biomaterials. In this Tutorial, we focus on fruits as new structures have recently been discovered, leading to new opportunities for bioinspired technologies. We bring together a review of optical structures found in fruits from a physical optics perspective, with a consideration of each structure as an opportunity in bioinspired and biomimetic design.
PubDate: Mon, 19 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0208528
Issue No: Vol. 9, No. 8 (2024)
- Photoluminescent cooling with incoherent light
First page: 081301
Abstract: Optical refrigeration using anti-Stokes photoluminescence is now well established, especially for rare-earth-doped solids where cooling to cryogenic temperatures has recently been achieved. The cooling efficiency of optical refrigeration is constrained by the requirement that the increase in the entropy of the photon field must be greater than the decrease in the entropy of the sample. Laser radiation has been used in all demonstrated cases of optical refrigeration with the intention of minimizing the entropy of the absorbed photons. Here, we show that as long as the incident radiation is unidirectional, the loss of coherence does not significantly affect the cooling efficiency. Using a general formulation of radiation entropy as the von Neumann entropy of the photon field, we show how the cooling efficiency depends on the properties of the light source, such as wavelength, coherence, and directionality. Our results suggest that the laws of thermodynamics permit optical cooling of materials with incoherent sources, such as light emitting diodes and filtered sunlight, almost as efficiently as with lasers. Our findings have significant and immediate implications for design of compact all-solid-state devices cooled via optical refrigeration.
PubDate: Thu, 22 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0217272
Issue No: Vol. 9, No. 8 (2024)
- 5–13.5 μ m broadband tunable long-wave infrared
femtosecond laser
First page: 086101
Abstract: We introduce a broadband tunable femtosecond laser source in the long-wave infrared (LWIR) band, covering the range of 5–13.5 μm, based on the integration of optical parametric amplification and difference frequency generation techniques. We utilize a dual-stage tuning method, combined with the high nonlinear coefficient and broadband phase matching range of the BaGa4Se7 crystal, to facilitate significant improvements in spectral coverage and energy efficiency. The laser yields a peak output energy of 43 μJ and maintains energies above 10 μJ across the entire tuning range, with an average power output exceeding 10 mW. The pulse duration at the central wavelength of 8.3 μm is measured at 72 fs full width at half-maximum using the electro-optic sampling method. This LWIR femtosecond laser can be used in many applications, such as molecular fingerprint spectral analysis, ultrafast chemical reaction spectral analysis, materials science, and ultrafast physics research, providing an important research basis for the generation and application of mid-infrared ultrafast laser sources.
PubDate: Thu, 01 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0221273
Issue No: Vol. 9, No. 8 (2024)
- High-efficiency, broadband, and low-crosstalk 3D holography by multi-layer
holographic-lens integrated metasurface
First page: 086102
Abstract: Holographic display is considered the holy grail of photorealistic three-dimensional (3D) visualization technology because it can provide arbitrary wavefronts related to the essential visual cues of 3D images. Metasurfaces with exceptional high-pixel light modulation capability are increasingly favored for implementing high-quality 3D holography. However, current 3D metasurface holography always has some trade-offs among lots of algorithmic data, acceptable time, image quality, and structure complexity. Therefore, the development of a high-efficiency 3D metasurface holography device is still necessary to meet the increasing high space bandwidth product (SBP) of 3D technology. Here, based on the holographic-lens (HL) computer-generated hologram (CGH) algorithm, we experimentally demonstrate a new 3D metasurface holography device that integrates the 3D image phase cues and multiple layers of virtual lenses with different focal lengths, which exhibits significant capabilities in terms of ultra-high spatial pixel modulation and the generation of high-quality 3D holography characterized by high-efficiency, broadband response, low-crosstalk, and reduced acceptable time. The HL-CGH algorithm was efficiently integrated into parameter-optimized α-Si nanopillar meta-atoms, enabling enhanced visualization of 3D clues in a lens-free system. The prepared 3D HL-metasurface holography presented the presence of multiple depths of a 3D holographic image across a broad spectral range (400–900 nm), providing enhanced 3D visual cues. Our work provides a new perspective on designing metasurface-driven high-SBP 3D holography.
PubDate: Fri, 02 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0218862
Issue No: Vol. 9, No. 8 (2024)
- High-power in-phase and anti-phase mode emission from linear arrays of
resonant-tunneling-diode oscillators in the 0.4-to-0.8-THz frequency range
First page: 086103
Abstract: Oscillators based on resonant tunneling diodes (RTDs) are able to reach the highest oscillation frequency among all electronic THz emitters. However, the emitted power from RTDs remains limited. Here, we propose linear RTD oscillator arrays capable of supporting coherent emission from both in-phase and anti-phase coupled modes. The oscillation modes can be selected by adjusting the mesa areas of the RTDs. Both the modes exhibit constructive interference at different angles in the far field, enabling high-power emission. Experimental demonstrations of coherent emission from linear arrays containing 11 RTDs are presented. The anti-phase mode oscillates at ∼450 GHz, emitting about 0.7 mW, while the in-phase mode oscillates at around 750 GHz, emitting about 1 mW. Moreover, certain RTD oscillator arrays exhibit dual-band operation: changing the bias voltage allows for controllable switching between the anti-phase and in-phase modes. Upon bias sweeping in both directions, a notable hysteresis feature is observed. Our linear RTD oscillator array represents a significant step forward in the realization of large arrays for applications requiring continuous-wave THz radiation with substantial power.
PubDate: Wed, 07 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0213695
Issue No: Vol. 9, No. 8 (2024)
- Load-dependent optical coherence tomography attenuation imaging: How
tissue mechanics can influence optical scattering
First page: 086104
Abstract: Mechanical load imparted to tissue, for example via handheld imaging probes, leads to tissue deformation, altering the distribution of tissue microstructure and, consequently, attenuation of light and image formation in optical imaging. In mechanically heterogeneous tissue, the load can result in spatially varying deformation and, therefore, spatially varying changes in the attenuation of light, which may provide additional image contrast. To investigate this potential, an assessment of the spatially resolved impact of mechanical deformation of the tissue on optical imaging is critical; however, it is challenging to incorporate stress mapping into optical imaging without obscuring the detection of photons. To address this, we present the novel integration of stress imaging using optical palpation with attenuation imaging based on optical coherence tomography (OCT). The method was implemented using a compliant silicone sensor incorporated into a custom handheld OCT probe, providing two-dimensional stress imaging with concurrent attenuation imaging. Attenuation imaging with varying mechanical loads was demonstrated on 19 tissue regions acquired from eight freshly excised human breast specimens. The results demonstrated distinct characteristics for different breast tissue types: benign stroma showed relatively large increases in attenuation (e.g., ∼0.3 to 0.4 mm−1/kPa) over a low stress range (∼2 to 10 kPa), while cancerous tissue showed markedly small increases in attenuation (e.g., ∼0.005 to 0.02 mm−1/kPa) mainly over a medium to high stress range (∼10 to 90 kPa). The integration of stress imaging with attenuation imaging provided a pilot assessment of the spatially resolved impact of tissue mechanical heterogeneity on optical attenuation, providing novel image contrast by encoding variations in mechanical properties on optical attenuation in tissue.
PubDate: Wed, 14 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0208026
Issue No: Vol. 9, No. 8 (2024)
- Optical coherence tomography imaging and noise characterization based on
1- μ m microresonator frequency combs
First page: 086105
Abstract: Spectral-domain optical coherence tomography is a pervasive, non-invasive, in vivo biomedical imaging platform that currently utilizes incoherent broadband superluminescent diodes to generate interferograms from which depth and structural information are extracted. Advancements in laser frequency microcombs have enabled the chip-scale broadband generation of discrete frequency sources, with prior soliton and chaotic comb states examined in discrete spectral-domain optical coherence tomography at 1.3 μm. In this work, we demonstrate coherence tomography through Si3N4 microresonator laser frequency microcombs at 1 μm, achieving imaging qualities on-par with or exceeding the equivalent commercial optical coherence tomography system. We characterize the noise performance of our frequency comb states and additionally show that inherent comb line amplitude fluctuations in a chaotic state and the resultant tomograms can be compensated via multi-scan averaging.
PubDate: Thu, 15 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0215574
Issue No: Vol. 9, No. 8 (2024)
- Linewidth narrowing in self-injection locked lasers: Effects of quantum
confinement
First page: 086106
Abstract: This paper explores the impact of gain medium on linewidth narrowing in integrated self-injection locked III–V/SiN lasers, theoretically and experimentally. We focus on the effects of carrier densities of states in zero- and two-dimensional structures due to quantum-dot and quantum-well confinement. The theoretical approach includes (a) multimode laser interaction to treat mode competition and wave mixing, (b) quantum-optical contributions from spontaneous emission, and (c) composite laser/free-space eigenmodes to describe outcoupling and coupling among components within an extended cavity. For single-cavity lasers, such as distributed feedback lasers, the model reproduces the experimentally observed better linewidth performance of quantum-dot active regions over quantum-well ones. When applied to integrated III–V/SiN lasers, our analysis indicates Hz-level linewidth performance for both quantum-dot and quantum-well gain media due to overcoming the difference in carrier-induced refractive index by incorporating a high-Q SiN passive resonator. Trade-offs are also explored between linewidth, output power, and threshold current.
PubDate: Fri, 16 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0214254
Issue No: Vol. 9, No. 8 (2024)
- Low-dispersive silicon nitride waveguide resonators by nanoimprint
lithography
First page: 086107
Abstract: In this study, we demonstrate the fabrication of waveguide resonators using nanoimprint technology. Without relying on traditionally costly lithography methods, such as electron-beam lithography or stepper lithography, silicon nitride (Si3N4) resonators with high-quality factors up to the order of 105 can be realized at C-band by nanoimprint lithography. In addition, by properly designing the waveguide geometry, a low-dispersive waveguide can be achieved with waveguide dispersion at around −35 ps/nm/km in the normal dispersion regime, and the waveguide dispersion can be further tuned to be 29 ps/nm/km in the anomalous dispersion regime with the polymer cladding. The tunability of nanoimprinted devices is demonstrated by the aid of microheaters, realizing on-chip optical functionalities. This work offers the potential to fabricate low-dispersive waveguide resonators for integrated modulators and filters in a significantly cost-effective and process-friendly scheme.
PubDate: Mon, 19 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0204857
Issue No: Vol. 9, No. 8 (2024)
- Below the surface: Unraveling the intricacies of the nonlinear optical
properties of aluminum through bound electrons
First page: 086108
Abstract: By uncovering novel aspects of second harmonic generation in aluminum, we show that there are unusual and remarkable consequences of resonant absorption, namely an unexpectedly critical role that bound electrons play for light–matter interactions across the optical spectrum, suggesting that a different basic approach is required to fully explain the physics of surfaces. We tackle an issue that is never under consideration given the generic hostile conditions to the propagation of light under resonant absorption. Unlike most noble metals, aluminum displays Lorentz-like behavior and interband transitions centered near 810 nm, thus splitting the plasmonic range in an atypical manner and setting its linear and nonlinear optical properties apart. Studies of aluminum nanostructures having complex topologies abound, as do reported inconsistencies in the linear spectral response of surface plasmons and harmonic generation. Our experimental observations of second harmonic generation from aluminum nanolayers show that bound electrons are responsible for a unique signature neither predicted nor observed previously: a hole in the second harmonic spectrum. A hydrodynamic-Maxwell theory explains these findings exceptionally well and becomes the basis for renewed studies of surface physics.
PubDate: Tue, 20 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0219007
Issue No: Vol. 9, No. 8 (2024)
- All-thin film nano-optoelectronic p -GeSn/i-GeSn/n-GeBi heterojunction for
near-infrared photodetection and terahertz modulation
First page: 086109
Abstract: High-performance alloy thin films and large-sized thin film wafers for infrared applications are the focus of international researchers. In this study, doped Ge1−xSnx and Ge1−yBiy semiconductor alloy films were grown on a 5-in. silicon (Si) wafer using high-quality Ge films as buffer layers. An efficient technique is presented to reduce the dark current density of near-infrared photoelectric devices. By using boron for p-type doping in Ge1−xSnx films and bismuth (Bi) for n-type doping in Ge1−yBiy films, an all-thin film planar nano-p-i-n optoelectronic device with the structure n-Ge1−yBiy/i-GeSn/p-Ge1−xSnx/Ge buffer/Si substrate has been successfully fabricated. The photoelectric performance of the device was tested, and it was found that the insertion of p-Ge1−xSnx/Ge films reduced the dark current density by 1–2 orders of magnitude. The maximum photoresponsivity reached up to 0.8 A/W, and the infrared photocurrent density ranged from 904 to 935 μA/cm2 under a +1 V bias voltage. Furthermore, the device is capable of modulating a terahertz wave using a voltage signal with a modulation bandwidth of 1.2 THz and a modulation depth of ∼83%, while the modulation rate is 0.5 MHz. This not only provides a clear demonstration of how doped alloy films and the development of nano-p-i-n heterojunctions will improve photoelectric devices’ performance in the near-infrared and terahertz bands, but it also raises the possibility of optoelectronic interconnection applications being achieved through a single device.
PubDate: Wed, 21 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0225536
Issue No: Vol. 9, No. 8 (2024)
- Thousand foci coherent anti-Stokes Raman scattering microscopy
First page: 086110
Abstract: We demonstrate coherent anti-Stokes Raman scattering (CARS) microscopy with 1089 foci, enabled by a high repetition rate amplified oscillator and an optical parametric amplifier. We employ a camera as a multichannel detector to acquire and separate the signals from the foci, rather than using the camera image itself. This allows us to retain the insensitivity of the imaging to scattering afforded by the non-linear excitation point-spread function, which is the hallmark of point-scanning techniques. We show frame rates of 0.3 Hz for a megapixel CARS image, limited by the camera used. The laser source and corresponding CARS signal allows for at least 1000 times higher speed, and using faster cameras would allow acquiring at that speed, opening a perspective to megapixel CARS imaging with a frame rate of more than 100 Hz.
PubDate: Wed, 21 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0220474
Issue No: Vol. 9, No. 8 (2024)
- Time stretch with continuous-wave lasers
First page: 086111
Abstract: Ultrafast single-shot measurement techniques with high throughput are needed for capturing rare events that occur over short time scales. Such instruments unveil non-repetitive dynamics in complex systems and enable new types of spectrometers, cameras, light scattering, and lidar systems. Photonic time stretch stands out as the most effective method for such applications. However, practical uses have been challenged by the reliance of current time stretch instruments on costly supercontinuum lasers and their fixed spectrum. The challenge is further exacerbated by such a laser’s rigid self-pulsating characteristic, which offers no ability to control the pulse timing. The latter hinders the synchronization of the optical source with the incoming signal—a crucial requirement for the detection of single-shot events. Here, we report the first demonstration of time stretch using electro-optically modulated continuous wave lasers. We do this using diode lasers and modulators commonly used in wavelength-division-multiplexing optical communication systems. This approach offers more cost-effective and compact time stretch instruments and sensors and enables the synchronization of the laser source with the incoming signal. Limitations of this new approach are also discussed, and applications in time stretch microscopy and light scattering are explored.
PubDate: Thu, 22 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0212958
Issue No: Vol. 9, No. 8 (2024)
- A quasi-matching scheme for arbitrary group velocity match in
electro-optic modulation
First page: 086112
Abstract: Group velocity and impedance matches are prerequisites for high-speed Mach–Zehnder electro-optic (EO) modulators. However, not all platforms can realize matching conditions, restricting high-speed modulation in many practical conditions. Here, we propose and demonstrate a quasi-matching scheme to satisfy the group velocity and characteristic impedance matches by cascading fast-wave and slow-wave traveling wave electrodes. The effective group velocity can be flexibly adjusted by changing the ratio of fast-wave and slow-wave traveling wave electrodes. Moreover, the quasi-matching scheme is experimentally verified by demonstrating a 6 mm long EO modulator on a thin-film lithium-niobate-on-insulator platform with a silica cladding. The radio frequency signal insertion loss at the boundary of the slow-wave and fast-wave electrodes is less than 0.12 dB. The measured small signal EO response of the quasi-matched EO modulator drops less than 2 dB at 67 GHz, while the measured small-signal EO responses of conventional slow and fast traveling wave EO modulators drop 4 dB at 67 GHz. The measured 100 Gb/s on–off key signal eye-diagrams of the quasi-matched EO modulator also exhibit an overwhelming advantage over conventional schemes. Therefore, our results will open many opportunities for high-speed EO modulators in various platforms.
PubDate: Mon, 26 Aug 2024 00:00:00 GMT
DOI: 10.1063/5.0220022
Issue No: Vol. 9, No. 8 (2024)
