Contents
2019
Volume: 7 Issue 6
19 Article(s)

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Research Articles
Fiber Optics and Optical Communications
High-performance optical chirp chain BOTDA by using a pattern recognition algorithm and the differential pulse-width pair technique
Benzhang Wang, Baohua Fan, Dengwang Zhou, Chao Pang, Yue Li, Dexin Ba, and Yongkang Dong
Optical chirp chain Brillouin optical time-domain analysis (OCC-BOTDA) has the capabilities of fast measurement, high Brillouin threshold, and freedom from the nonlocal effect; at the same time, however, it also has problems introduced by transient stimulated Brillouin scattering. The influence of the transient interaction is reflected as the broadened asymmetric Brillouin spectrum, the ghost peak, and the frequency shift of the main peak. This introduces difficulty in computing the fiber Brillouin frequency shift with good measurement accuracy. Besides, the OCC modulation causes additional noise due to the uneven amplitude response for different frequency components. In this work, we propose a high-performance OCC-BOTDA using the principal component analysis (PCA) based pattern recognition algorithm and differential pulse-width pair (DPP) technique. After building the Brillouin spectrum database (i.e., all patterns), the fiber intrinsic Brillouin frequency shift can be recognized by the PCA algorithm from a nonstandard Brillouin spectrum profile, resulting in good measurement accuracy. Meanwhile, the DPP technique, subtracting between two Brillouin signals generated by two wide-width pump pulses, is utilized to reduce the OCC modulation noise and avoid the pulse self-phase modulation effect in long-range BOTDA sensing. In the experiment, a temperature measurement with 1.3?MHz measurement precision, 4?m spatial resolution, and 5?s measurement time is achieved over a 100?km single-mode fiber.
Photonics Research
  • Publication Date: May. 28, 2019
  • Vol. 7, Issue 6, 652 (2019)
Instrumentation and Measurements
Spectral measurement of coherence Stokes parameters of random broadband light beams | On the Cover
Henri Partanen, Ari T. Friberg, Tero Set?l?, and Jari Turunen
Photonics Research
  • Publication Date: May. 29, 2019
  • Vol. 7, Issue 6, 669 (2019)
Lasers and Laser Optics
GaN-based ultraviolet microdisk laser diode grown on Si
Jin Wang, Meixin Feng, Rui Zhou, Qian Sun, Jianxun Liu, Yingnan Huang, Yu Zhou, Hongwei Gao, Xinhe Zheng, Masao Ikeda, and Hui Yang
This work reports a demonstration of electrically injected GaN-based near-ultraviolet microdisk laser diodes with a lasing wavelength of 386.3?nm at room temperature. The crack-free laser structure was epitaxially grown on Si substrates using an Al-composed down-graded AlN/AlGaN multilayer buffer to mitigate the mismatches in the lattice constant and coefficient of thermal expansion, and processed into “sandwich-like” microdisk structures with a radius of 12?μm. Air-bridge electrodes were successfully fabricated to enable the device electrical characterization. The electrically pumped lasing of the as-fabricated microdisk laser diodes was evidenced by the rapid narrowing down of electroluminescence spectra and dramatic increase in the light output power, as the current exceeded the threshold of 248?mA.
Photonics Research
  • Publication Date: May. 20, 2019
  • Vol. 7, Issue 6, B32 (2019)
Nonlinear Optics
Intermodal frequency generation in silicon-rich silicon nitride waveguides
C. Lacava, T. Dominguez Bucio, A. Z. Khokhar, P. Horak, Y. Jung, F. Y. Gardes, D. J. Richardson, P. Petropoulos, and F. Parmigiani
Dispersion engineering in optical waveguides allows applications relying on the precise control of phase matching conditions to be implemented. Although extremely effective over relatively narrow band spectral regions, dispersion control becomes increasingly challenging as the bandwidth of the process of interest increases. Phase matching can also be achieved by exploiting the propagation characteristics of waves exciting different spatial modes of the same waveguide. Phase matching control in this case relies on achieving very similar propagation characteristics across two, and even more, waveguide modes over the wavelengths of interest, which may be rather far from one another. We demonstrate here that broadband (>40??nm) four-wave mixing can be achieved between pump waves and a signal located in different bands of the communications spectrum (separated by 50?nm) by exploiting interband nonlinearities. Our demonstration is carried out in the silicon-rich silicon nitride material platform, which allows flexible device engineering, allowing for strong effective nonlinearity at telecommunications wavelengths without deleterious nonlinear-loss effects.
Photonics Research
  • Publication Date: May. 08, 2019
  • Vol. 7, Issue 6, 615 (2019)
Terahertz wave generation from liquid nitrogen
Alexei V. Balakin, Jean-Louis Coutaz, Vladimir A. Makarov, Igor A. Kotelnikov, Yan Peng, Peter M. Solyankin, Yiming Zhu, and Alexander P. Shkurinov
Photonics Research
  • Publication Date: May. 28, 2019
  • Vol. 7, Issue 6, 678 (2019)
Broadband mid-infrared nonlinear optical modulator enabled by gold nanorods: towards the mid-infrared regime
Bin Huang, Zhe Kang, Jie Li, Mingyi Liu, Pinghua Tang, Lili Miao, Chujun Zhao, Guanshi Qin, Weiping Qin, Shuangchun Wen, and Paras N. Prasad
Mid-infrared pulsed lasers operating around the 3?μm wavelength regime are important for a wide range of applications including sensing, spectroscopy, imaging, etc. Despite the recent advances in technology, the lack of a nonlinear optical modulator operating in the mid-infrared regime remains a significant challenge. Here, we report the third-order nonlinear optical response of gold nanorods (GNRs) ranging from 800?nm to the mid-infrared regime (2810?nm) enabled by their size and overlapping behavior-dependent longitudinal surface plasmon resonance. In addition, we demonstrate a wavelength-tunable Er3+-doped fluoride fiber laser modulated by GNRs, which can deliver pulsed laser output, with the pulse duration down to 533?ns, tunable wavelength ranging from 2760.2 to 2810.0?nm, and spectral 3?dB bandwidth of about 1?nm. The experimental results not only validate the GNRs’ robust mid-infrared nonlinear optical response, but also manifest their application potential in high-performance broadband optoelectronic devices.
Photonics Research
  • Publication Date: Jun. 04, 2019
  • Vol. 7, Issue 6, 699 (2019)
Optical Devices
Ultra-high-resolution detection of Pb2+ ions using a black phosphorus functionalized microfiber coil resonator
Yu Yin, Shi Li, Shunbin Wang, Shijie Jia, Jing Ren, Gerald Farrell, Elfed Lewis, and Pengfei Wang
A black phosphorus (BP) functionalized optical fiber sensor based on a microfiber coil resonator (MCR) for Pb2+ ion detection in an aquatic environment is presented and experimentally demonstrated. The MCR-BP sensor is manufactured by winding a tapered microfiber on a hollow rod composed of a low-refractive-index polycarbonate (PC) resin with the BP deposited on the internal wall of the rod. Based on the propagation properties of the MCR, the chemical interaction between the Pb2+ ions and the BP alters the refractive index of the ambient environment and thus results in a detectable shift in the transmission spectrum. The resonance wavelength moves towards longer wavelengths with an increasing concentration of Pb2+ ions, and the sensor has an ultra-high detection resolution of 0.0285 ppb (parts per billion). The temperature dependence is 106.95 pm/°C due to the strong thermo-optic and thermal-expansion effect of the low-refractive-index PC resin. In addition, the sensor shows good stability over a period of 15 days. The local pH also influences the sensor, with the resonance wavelength shift increasing as pH approaches a value of 7 but then decreasing as the pH value increases further due to the effect of the BP layer by H+ and OH? ions. The sensor shows the potential for high-resolution detection of Pb2+ ions in a liquid environment with the particular advantages of having a simple structure, ease of fabrication, low cost, low loss, and simple interrogation.
Photonics Research
  • Publication Date: May. 08, 2019
  • Vol. 7, Issue 6, 622 (2019)
Mode splitting revealed by Fano interference
Yue Wang, Hongchun Zhao, Yancheng Li, Fengfeng Shu, Mingbo Chi, Yang Xu, and Yihui Wu
An optical whispering gallery mode (WGM) resonator supports degenerate counter-propagating modes and the degeneracy is lifted as mode splitting due to Rayleigh scattering. However, quantitative analysis becomes difficult if the resonance experiences weak scattering. Here we develop a spectroscopical method to identify an arbitrary small scatterer using the Fano interference-induced spectral response modification. Scattering information can be revealed by fitting the responses as a function of the field’s phase and intensity. In addition, we show that this modified response helps achieve an ultra-low detection limit for the mode-splitting-based nanoparticle detection method. This approach may be promising in the characterization of high-Q-factor devices, novel sensing methods, and quantum coupling system investigation.
Photonics Research
  • Publication Date: May. 17, 2019
  • Vol. 7, Issue 6, 647 (2019)
Direct modulation characteristics of microdisk lasers with InGaAs/GaAs quantum well-dots
N. V. Kryzhanovskaya, E. I. Moiseev, F. I. Zubov, A. M. Mozharov, M. V. Maximov, N. A. Kalyuzhnyy, S. A. Mintairov, M. M. Kulagina, S. A. Blokhin, K. E. Kudryavtsev, A. N. Yablonskiy, S. V. Morozov, Yu. Berdnikov, S. Rouvimov, and A. E. Zhukov
Photonics Research
  • Publication Date: May. 29, 2019
  • Vol. 7, Issue 6, 664 (2019)
Physical Optics
Observation of polarization topological singular lines
Guan-Lin Zhang, Chenghou Tu, Yongnan Li, and Hui-Tian Wang
Photonics Research
  • Publication Date: Jun. 04, 2019
  • Vol. 7, Issue 6, 705 (2019)
Quantum Optics
Nonreciprocal unconventional photon blockade in a spinning optomechanical system
Baijun Li, Ran Huang, Xunwei Xu, Adam Miranowicz, and Hui Jing
Photonics Research
  • Publication Date: May. 15, 2019
  • Vol. 7, Issue 6, 630 (2019)
QUANTUM PHOTONICS
Sensing and tracking enhanced by quantum squeezing
Chuan Xu, Lidan Zhang, Songtao Huang, Taxue Ma, Fang Liu, Hidehiro Yonezawa, Yong Zhang, and Min Xiao
Quantum sensing, along with quantum communications and quantum computing, is commonly considered as the most important application of quantum optics. Among the quantum-sensing experiments, schemes based on squeezed states of light are popular choices due to their natural quadrature components. Since the first experimental demonstration of quantum-squeezing-enhanced phase measurement beyond the shot-noise limit in 1987, quantum-squeezing techniques toward practical sensing and tracking have been extensively investigated. In this paper, we briefly review the recent developments of quantum squeezing and its applications in several advanced systems for measurements of position, rotation, dynamic motion, magnetic fields, and gravitational waves. We also introduce the recent experimental efforts to combine the quantum-squeezing lights into fiber sensing systems.
Photonics Research
  • Publication Date: May. 08, 2019
  • Vol. 7, Issue 6, A14 (2019)
Semiconductor UV Photonics
Visible- and solar-blind photodetectors using AlGaN high electron mobility transistors with nanodot-based floating gate
Andrew M. Armstrong, Brianna A. Klein, Andrew A. Allerman, Albert G. Baca, Mary H. Crawford, Jacob Podkaminer, Carlos R. Perez, Michael P. Siegal, Erica A. Douglas, Vincent M. Abate, and Francois Leonard
AlGaN-channel high electron mobility transistors (HEMTs) were operated as visible- and solar-blind photodetectors by using GaN nanodots as an optically active floating gate. The effect of the floating gate was large enough to switch an HEMT from the off-state in the dark to an on-state under illumination. This opto-electronic response achieved responsivity >108??A/W at room temperature while allowing HEMTs to be electrically biased in the off-state for low dark current and low DC power dissipation. The influence of GaN nanodot distance from the HEMT channel on the dynamic range of the photodetector was investigated, along with the responsivity and temporal response of the floating gate HEMT as a function of optical intensity. The absorption threshold was shown to be controlled by the AlN mole fraction of the HEMT channel layer, thus enabling the same device design to be tuned for either visible- or solar-blind detection.
Photonics Research
  • Publication Date: May. 17, 2019
  • Vol. 7, Issue 6, B24 (2019)
Silicon Photonics
25 × 50 Gbps wavelength division multiplexing silicon photonics receiver chip based on a silicon nanowire-arrayed waveguide grating
Zhi Liu, Jiashun Zhang, Xiuli Li, Liangliang Wang, Jianguang Li, Chunlai Xue, Junming An, and Buwen Cheng
A high-performance monolithic integrated wavelength division multiplexing silicon (Si) photonics receiver chip is fabricated on a silicon-on-insulator platform. The receiver chip has a 25-channel Si nanowire-arrayed waveguide grating, and each channel is integrated with a high-speed waveguide Ge-on-Si photodetector. The central wavelength, optical insertion loss, and cross talk of the array waveguide grating are 1550.6?nm, 5–8?dB, and ?12–?15??dB, respectively. The photodetectors show low dark current density of 16.9??mA/cm2 at ?1??V and a high responsivity of 0.82?A/W at 1550?nm. High bandwidths of 23 and 29?GHz are achieved at 0 and ?1??V, respectively. Each channel can operate at 50?Gbps with low input optical power even under zero bias, which realizes an aggregate data rate of 1.25?Tbps.
Photonics Research
  • Publication Date: May. 29, 2019
  • Vol. 7, Issue 6, 659 (2019)
4λ hybrid InG
Yajie Li, Hongyan Yu, Wengyu Yang, Chaoyang Ge, Pengfei Wang, Fangyuan Meng, Guangzhen Luo, Mengqi Wang, Xuliang Zhou, Dan Lu, Guangzhao Ran, and Jiaoqing Pan
A 4–λ hybrid InGaAsP-Si evanescent laser array is obtained by bonding III–V distributed feedback lasers to a silicon on insulator (SOI) substrate using a selective area metal bonding technique. Multiple wavelengths are realized by varying the width of the III–V ridge waveguide. The threshold current is less than 10?mA for all wavelength channels under continuous-wave (CW) operation at room temperature, and the lowest threshold current density is 0.76??kA/cm2. The side mode suppression ratio (SMSR) is higher than 40?dB for all wavelength channels when the injection current is between 20?mA and 70?mA at room temperature, and the highest SMSR is up to 51?dB. A characteristic temperature of 51?K and thermal impedance of 144°C/W are achieved on average. The 4–λ hybrid InGaAsP-Si evanescent laser array exhibits a low threshold and high SMSR under CW operation at room temperature. The low power consumption of this device makes it very attractive for on-chip optical interconnects.
Photonics Research
  • Publication Date: Jun. 04, 2019
  • Vol. 7, Issue 6, 687 (2019)
Surface Optics and Plasmonics
Routing emission with a multi-channel nonreciprocal waveguide
Hao Hu, Liangliang Liu, Xiao Hu, Dongjue Liu, and Dongliang Gao
In this work, we present a multi-channel nonreciprocal waveguide, which is composed of a gyrotropic-bounded dielectric on the bottom and a plasmonic material on the top. The Lorentz reciprocity in the time-invariant system is broken when applying an external static magnetic field on the gyrotropic material. The nonreciprocal emission from the dipole source located in the center of the waveguide is observed in extended waveband channels. The proposed heterostructure serves as a photonic dichroism once the dielectric is replaced by a nonlinear material. The associated second harmonic generated in the nonlinear process can be separated from the fundamental signal under proper magnetic field intensity. Our findings may provide significant guidance for designing nonreciprocal photonic devices with superiorities of a tunable waveband, multiple channels, and small footprint.
Photonics Research
  • Publication Date: May. 15, 2019
  • Vol. 7, Issue 6, 642 (2019)
Selective excitation of a three-dimensionally oriented single plasmonic dipole
Fajun Xiao, Guanglin Wang, Xuetao Gan, Wuyun Shang, Shiyin Cao, Weiren Zhu, Ting Mei, Malin Premaratne, and Jianlin Zhao
We experimentally demonstrate a scheme to deterministically excite a three-dimensionally oriented electric dipole in a single Au nanosphere by using a tightly focused radially polarized beam whose focal field possesses polarization states along three-dimensional (3D) orientations owing to the spatial overlap between longitudinal and radial electric field components. Experiment observations indicate that the orientation of an excited dipole moment gradually changes from out-of-plane to in-plane when the nanosphere is moved away from the beam center, which is reconfirmed by full-wave simulations. Moreover, rigorous calculation based on Mie theory reveals that a reduced effective ambient permittivity accompanies the rotation of the dipole moment, leading to a blue-shifted and narrowed resonance peak. We envision that our results could find applications in detecting the 3D orientation of isolated molecules and benefit the fine manipulation of light–matter interactions at the single-molecule level.
Photonics Research
  • Publication Date: Jun. 04, 2019
  • Vol. 7, Issue 6, 693 (2019)