- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Frequency Comb Generation and Conversion in Non-Centrosymmetric Optical Microresonators
摘要： Optical frequency combs have become the key technology in optical precision measurements [1], bear a high potential for broadband, high-resolution molecular spectroscopy [2] and are promising to advance future optical clocks [3]. For low-power, compact and mobile applications, high-repetition-rate combs such as continuous-wave-pumped Kerr combs [4] and soliton frequency combs based on a third-order nonlinearity [5] have turned out to be especially useful. Thus far, most of these frequency combs operate in the near-infrared (NIR) spectral regime around 1550 nm for reasons such as chromatic material dispersion. Many applications ranging from astronomical spectroscopy, optical clocks and quantum physics all the way to molecular sensing, however, require the frequency combs to be centered in the ultraviolet (UV), visible (VIS) and mid-infrared (MIR) spectral regimes [3,6-8]. In this contribution, we present pathways towards achieving this goal. In a first approach [9], synchronously pumped high-Q whispering gallery-mode resonators with a second-order nonlinearity are employed to convert a high-repetition-rate (21 GHz) NIR comb into the VIS and UV wavelength regimes at the same time (see Fig. 1(a)), using an engineered quasi-phase-matching structure. Furthermore, via degenerate optical parametric oscillation (OPO) the sub-harmonic of the initial comb in the MIR can be generated; non-degenerate OPO even allows for wavelength-tunable signal and idler combs. These results pave the way towards a phase-coherent link of frequency combs across the UV, VIS, NIR and MIR spectral regions in a single microresonator. This could allow for low-power self-referenced frequency combs without the need for octave-spanning spectra (e.g. via 3f-4f-interferometry). Additionally, we show first results towards achieving frequency combs purely based on second-order nonlinearities in few-mode optical microresonators (see Fig. 1(b)). This type of combs not only allows to potentially access wavelength regimes different from the NIR, but they also come with the opportunity to use fast electro-optic tuning, a method that is very weak for Kerr microcombs.
关键词： optical frequency combs,nonlinear optics,microresonators,frequency conversion
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - UV-Grade Silica-Based Photonic Crystal Fibers for Broadband UV Generation over 350–395 nm
摘要： A major challenge in supercontinuum (SC) generation is to overcome the shortcomings of existing fibre-based SC sources in the ultraviolet (UV) wavelength range below 400 nm. There is particular need for broadband sources of UV light in applications such as multi-photon fluorescence microscopy for simultaneous coherent excitation of multiple fluorophores. However, UV generation in conventional silica-core fibres is extremely difficult because of factors such as material absorption, large normal dispersion, glass stability, power handling, and aging, and this has motivated much recent interest in the use of alternative approaches. Although these results show great promise, compatibility with the ubiquitous silica platform remains a problem, and there is thus intense current interest in generating UV-light using modified UV-resistant silica glasses. In this paper, we report the design and fabrication of small-core highly nonlinear UV-grade photonic crystal fiber (PCF) drawn from Heraeus F110 UV-resistant silica glass, and its application to broadband UV generation over 260-400 nm. The few mode PCF is shown in Fig. 1(a) and was designed with: core diameter ~4.24 μm, hole diameter d = 3.5 μm, pitch Λ =3.88 μm, and was designed to support five LP modes in a scalar approximation. The calculated dispersion coefficients and mode profiles are shown in Figs 1(b) and (c). Figure 1(d) and (e) show experimental results pumping with picosecond laser pulses at 355 nm. For a 1m length of the PCF, we observe intermodal four-wave mixing (FWM) peaks with Fig. 1(d) showing a series of spectra as the output power varies from 0.1 – 0.2 mW. The FWM peaks are generated over the range 350-370 nm and the peak positions are in good agreement with calculations based on the fibre modal characteristics. For a longer 3 m fibre length, intermodal FWM is not observed, but rather we see cascaded Raman scattering out to 6th-order over the range 355-395 nm. The UV-emission was observed to have stable 0.3 mW output power without any detrimental photo-darkening. In this paper, we have reported the fabrication of highly nonlinear photonic crystal fiber from UV-grade glass and experimentally demonstrate nonlinear frequency conversion over 350-395 nm by pumping at 355 nm with picosecond laser pulses. These results represent an important step towards efficient UV supercontinuum generation in an all-silica fiber platform.
关键词： nonlinear frequency conversion,broadband UV generation,supercontinuum generation,UV-grade silica-based photonic crystal fibers,UV-resistant silica glass
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Optically Engineered Nonlinear Photonic Structures in Ferroelectrics
摘要： Performance of many optical devices based on frequency conversion critically depends on spatial modulation of the nonlinear optical response of the materials. This modulation ensures, via the quasi phase matching (QPM), an efficient energy exchange between optical waves at different frequencies. The QPM structures, also known as the nonlinear photonic crystals, offer a variety of novel properties and functionalities that cannot be obtained in uniform nonlinear crystals. Typically, such nonlinear structures have been fabricated via electric-poling. However, this technique is restricted to particular crystallographic geometries, and does not allow to create isolated structures inside the nonlinear material. This means that one cannot realize fully 3-dimensional nonlinear structures via traditional electrical poling. In this work we discuss our novel technique capable of engineering quadratic nonlinearity, based on all-optical poling of ferroelectrics. This new approach, is similar to traditional laser writing in optical media. It involves a tight focusing of femtosecond infrared beam and subsequent its two photon absorption which heats locally the medium. The large temperature gradient induces thermoelectric field which, if sufficiently high, inverts locally direction of spontaneous polarization, changing the sign of nonlinearity. The method is extremely flexible, can be applied to different crystallographic orientations and enables formation of localised spatially modulated nonlinear response inside optical media. Here, we demonstrate its application to create structures for efficient frequency conversion in Lithium Niobate waveguides and transverse second harmonic generation. Moreover, we provide here the first ever experimental evidence of the 3D Nonlinear Photonic Crystal, fabricated in ferroelectric barium calcium titanate. Finally we show formation of multiple nonlinear photonic crystals in form of fork structures inside the bulk of ferroelectric calcium barium niobate, and demonstrate their application for wave-shaping in frequency doubling process, directly creating second harmonic optical vortices and conical beams.
关键词： frequency conversion,nonlinear photonic structures,ferroelectrics,all-optical poling,second harmonic generation,quasi phase matching
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Conversion of two Photons with Different Color by a Single Waveguide for Quantum Networks
摘要： Quantum communication would enable opportunities such as secure communication. A quantum network with quantum nodes and quantum channels is necessary for this. The realization of such a quantum network requires the ability to process, store and send photons over long distances. It is not very likely that a single physical system can accomplish all these operations. Therefore, dissimilar quantum systems have to be connected in future quantum networks. Quantum channels are likely to be based on the existing fiber network because it is already well established. The fiber network operates at telecom wavelength (1550 nm) since the losses in fibers are minimal at this wavelength. That is why quantum states at telecom wavelength are needed. Unfortunately, suitable single photon sources and quantum memories are not available at telecom wavelength. Frequency conversion provides the possibility to alter the wavelength of a single photon to another wavelength. With frequency conversion it is possible to convert the VIS/NIR single photon to telecom wavelength and transfer the state over long distances. However, quantum networks do not require single photons but rather entangled photon pairs. Quantum dots are able to generate entangled photon pairs via a biexciton cascade emission. The emitted photons of a cascaded emission usually have slightly different wavelengths. The frequency conversion of the entangled photon pair on a single device would be advantageous for building quantum nodes for real life applications. We present a frequency conversion based on a single lithium niobate waveguide with different local temperatures to convert two different wavelengths on the same chip. The setup consists of a 2100 nm pump laser and a fiber coupled input port for the two biexciton photons (894 nm and 892 nm). These three wavelengths are focused by a lens into a nonlinear crystal with two different local temperatures. Each segment converts one of the incoming wavelengths. The converted signal is coupled into an optical fiber and guided to a filter system, which removes remaining pump light and generated noise photons. A proof of principle experiment was performed with attenuated laser light, where the converted spectrum is shown.
关键词： lithium niobate waveguide,frequency conversion,Quantum communication,entangled photon pairs,quantum network
更新于2025-09-11 14:15:04
-
260?W of average green beam generation by intracavity frequency-doubled acousto-optic Q-Switched Nd:YAG laser
摘要： We developed an intracavity frequency-doubled acousto-optic Q-switched Nd:YAG laser generating * 260 W of average green power using two identical diode-pumped gain modules with ?vefold pumping symmetry in a simple two mirror linear cavity con?guration. The corresponding optical to optical conversion ef?ciency was estimated to be * 16.8%. At maximum output power, individual green pulse duration (FWHM) was measured to be * 73 ns with a pulse repetition rate of 18 kHz. The output average green power was highly stable with measured ?uctuation in average green power ± 0.83 W over 5 h of continuous operation. The jitter in pulse delay time and pulse to pulse amplitude ?uctuation was measured to be within ± 4.25 ns and ± 5%, respectively. The maximum beam drift recorded at 5 m distance away from the laser system was * 14 micron corresponding to beam pointing stability of ± 2.8 micro-rad.
关键词： Acousto-optic Q-switching,Intracavity frequency conversion,Diode-pumped solid-state lasers,High-power green laser
更新于2025-09-11 14:15:04
-
A Multiband Transparent Transponder Based on Reconfigurable Optical Frequency Combs for Cross Connection of Intersatellite and Satellite Ground
摘要： In this paper, a parallel multiband frequency-conversion scheme for satellite applications based on a single optical frequency comb is proposed, and a recon?gurable satellite transponder is designed for future multiband broadband satellites. In addition, we establish a test system of onboard multiband frequency-conversion on the strength of microwave photonics and, a proof-of-concept experiment is demonstrated in which a Ka-band signal is converted to other satellite frequency bands. The experimental results reveal our system feasibility, and the bit error rate of recovered baseband data is less than 10–9. Moreover, the optical frequency combs can be recon?gured by adjusting the parameters of the local oscillator and optical modulator.
关键词： multi-band frequency conversion,Microwave photonics,recon?gurable satellite transponder.,optical frequency comb
更新于2025-09-10 09:29:36
-
400-Gb/s Single-Photodiode Polarization-Agnostic Kramers-Kronig Reception of Distributedly Aggregated Superchannel
摘要： In its most simple implementation, the Kramers-Kronig (KK) scheme allows the reception of complex modulation formats with a single photodiode. Thereby, in analogy to a heterodyne receiver, an additional continuous wave signal is used which allows under certain conditions the distortion-free reconstruction of the data signal. We present experimental investigations on a novel Kramers-Kronig scheme based on inherently carrier generation at the receiver. We use a distributed superchannel aggregation scheme to demonstrate ultra-wideband single-photodiode reception of a 3×33-GBd single-polarization 32QAM superchannel with this scheme. The impact of polarization rotations is discussed, and we show that variations in data or Kramers-Kronig carrier polarization will only affect the carrier-to-signal power ratio (CSPR), leading to an increase or decrease from the optimum CSPR by about 6 dB. 400-Gb/s net capacity is demonstrated for optimized conditions. In addition, we demonstrate transmission measurements over a 60-km standard single-mode fiber (SSMF) link with a 344-Gb/s net rate superchannel (3×28 GBd sub-carriers) with the novel Kramers-Kronig scheme.
关键词： optical frequency conversion,optical signal processing,Kramers-Kronig receiver,Direct detection,optical fiber communication,sub-carrier modulation
更新于2025-09-09 09:28:46
-
[IEEE 2018 13th European Microwave Integrated Circuits Conference (EuMIC) - Madrid, Spain (2018.9.23-2018.9.25)] 2018 13th European Microwave Integrated Circuits Conference (EuMIC) - Ultra-Broadband Frequency Multiplier MMICs for Communication and Radar Applications
摘要： Two H-band frequency multiplier MMICs, a frequency doubler and tripler, are presented. Both circuits were characterized over a frequency range of 235 - 285 GHz. The 3-dB bandwidth of both chips exceeds the measurement range of 50 GHz. Without any post-ampli?cation the multiplier-by-3 achieves an average output power of -6 dBm at an input power of 6 dBm. The multiplier-by-two generates -3.6 dBm average at an input power of 5 dBm. Both MMICs were realized in a 35 nm gate-length InGaAs-based metamorphic HEMT technology. A comparison of simulation and measurement was conducted and shows a very good correspondence.
关键词： S-MMIC,Frequency conversion,Millimeter wave communication
更新于2025-09-04 15:30:14
-
Frequency Conversion in KTP Crystal and Its Isomorphs
摘要： We report the results of an analysis of the functional capabilities of the KTP crystal and its isomorphs for nonlinear-optical frequency conversion of all types of interactions in the transparency range of the crystal. The possibility of implementing angle, wavelength (frequency), and temperature-noncritical phase matching is shown.
关键词： temperature-noncritical mode,nonlinear crystals,frequency conversion,KTP and isomorphs,functional capabilities
更新于2025-09-04 15:30:14