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[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) - An Iodine-Stabilized Laser using a 1542-nm Light Source
摘要： Frequency-stabilized lasers at the telecom wavelengths are of great interest for a wide range of applications, including wavelength standards for optical communication systems [1], and an absolute frequency marker of an optical frequency comb. Especially in astro-comb application [2], it is considered to be a good candidate of an optical frequency reference laser since it has a good frequency connection to a fiber-based frequency comb. Frequency-stabilized lasers at the telecom wavelengths are usually based on the acetylene combination band transitions [1], however, these transitions are relatively weak for frequency stabilization to realize high stability. On the other hand, molecular iodine has very strong absorption lines in the 500-nm wavelength region. Highly stable and reliable iodine-stabilized lasers have been realized by using frequency-doubled 1-μm lasers [3]. In this study, we developed an iodine-stabilized laser at the telecom wavelength by using frequency-tripled 1542-nm laser. In the previous study [4], third harmonic generation (THG) of a 1.5 μm laser has been demonstrated by using two periodically poled lithium niobate (PPLN) waveguides. On the other hand, as shown in the inset of Fig. 1(a), we used a dual-pitch PPLN waveguide (NTT Electronics Corporation WS-0514-000-A-C-C-TEC) which consists of two stages of PPLN with different polling periods for second harmonic generation (SHG, 1542 nm →771 nm) and sum frequency generation (SFG, 1542 nm + 771 nm →514 nm). Figure 1(a) shows the phase-matching curve of the waveguide for both SHG and SFG. The phase-matching curve for SHG is broadened because the PPLN has a chirped polling period in the first stage, which enables the satisfaction of both phase-matching conditions for SHG and SFG simultaneously. A maximum power of 1.7 mW was obtained when the 1.5-μm-laser output power was 200 mW. Doppler-free transition signals of molecular iodine were observed by saturation spectroscopy based on the modulation transfer technique [3]. The inset of Fig. 1(b) shows the obtained entire hyperfine components of the R(73)46-0 transition at 514 nm. The laser frequency was stabilized to the a1 hyperfine component of the observed transition. To evaluate the stability of the laser frequency, we measured the laser frequency using an optical frequency comb referenced to a H-maser. Figure 1(b) shows the measured Allan standard deviation that indicates the frequency stability of the developed laser. The Allan standard deviation was 1×10-11 for a 1-s averaging time. The short-term stability, limited by the signal-to-noise ratio of the transition signal, will be improved by increasing the laser power using a high-power erbium-doped fiber amplifier. As for the long-term stability, we need to verify the uncertainty factors that cause the long-term drift and remove them as possible.
关键词： iodine-stabilized laser,frequency-tripled 1542-nm laser,dual-pitch PPLN waveguide,Frequency-stabilized lasers,telecom wavelengths
更新于2025-09-16 10:30:52
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Telecommunication wavelength confined Tamm plasmon structures containing InAs/GaAs quantum dot emitters at room temperature
摘要： We experimentally demonstrate gold microdisc structures that produce con?ned Tamm plasmons (CTPs)— interface modes between a metal layer and a distributed Bragg re?ector— resonant around 1.3 μm. Quantum dots grown within the structures show an order of magnitude increase in the photoluminescence emitted at room temperature. Varying the disc diameter, we show spectral tuning of the resonance and measure the dispersion relation as evidence of mode con?nement. The simplicity of fabrication and tuneability of these structures make CTPs an ideal platform for making scalable telecom devices based on quantum dots.
关键词： Tamm plasmons,room temperature,photoluminescence,quantum dots,telecom wavelengths
更新于2025-09-12 10:27:22
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[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) - Broad-Band Optical Parametric Amplification in a Tapered Silicon Core Fiber Pumped in the Telecom Band
摘要： Silicon core ?bers (SCFs) are emerging as a robust and ?exible waveguide platform that can exploit the high nonlinear coef?cients of silicon to perform compact nonlinear processing within an integrated ?ber geometry. Optical parametric ampli?cation (OPA) based on four-wave mixing (FWM) has been studied intensively over the past decade using chip-based silicon waveguides for a variety of telecommunication applications such as all-optical signal sampling, time-demultiplexing, pulse generation, and wavelength conversion. However, due to the strong nonlinear absorption associated with two photon and free carrier effects in silicon at telecom wavelengths, net on/off parametric gain has not been observed using a continuous-wave (CW) signal, and even when using pulses the gain has been limited to be 5.2 dB. Here, by tapering the SCF to tailor the dimensions such that we can achieve high coupling ef?ciency into a core with a sub-micron-sized diameter, required to access the anomalous dispersion region, we demonstrate OPA with a positive on/off gain up to 6.6 dB and bandwidth of more than 220 nm. Eventually, when fully integrated with conventional ?bers and components to improve the robustness of the system, we expect these tapered SCFs will ?nd wide-ranging applications in areas that require ef?cient wavelength conversion across a broad spectral band.
关键词： optical parametric amplification,nonlinear absorption,Silicon core fibers,telecom wavelengths,four-wave mixing
更新于2025-09-11 14:15:04
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On-Demand CMOS-Compatible Fabrication of Ultrathin Self-Aligned SiC Nanowire Arrays
摘要： The field of semiconductor nanowires (NWs) has become one of the most active and mature research areas. However, progress in this field has been limited, due to the difficulty in controlling the density, orientation, and placement of the individual NWs, parameters important for mass producing nanodevices. The work presented herein describes a novel nanosynthesis strategy for ultrathin self-aligned silicon carbide (SiC) NW arrays (≤ 20 nm width, 130 nm height and 200–600 nm variable periodicity), with high quality (~2 ? surface roughness, ~2.4 eV optical bandgap) and reproducibility at predetermined locations, using fabrication protocols compatible with silicon microelectronics. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopic ellipsometry, atomic force microscopy, X-ray diffractometry, and transmission electron microscopy studies show nanosynthesis of high-quality polycrystalline cubic 3C-SiC materials (average 5 nm grain size) with tailored properties. An extension of the nanofabrication process is presented for integrating technologically important erbium ions as emission centers at telecom C-band wavelengths. This integration allows for deterministic positioning of the ions and engineering of the ions’ spontaneous emission properties through the resulting NW-based photonic structures, both of which are critical to practical device fabrication for quantum information applications. This holistic approach can enable the development of new scalable SiC nanostructured materials for use in a plethora of emerging applications, such as NW-based sensing, single-photon sources, quantum LEDs, and quantum photonics.
关键词： silicon carbide,telecom wavelengths,nanofabrication,self-aligned nanowires,ultrathin nanowires,quantum photonics
更新于2025-09-10 09:29:36