Ultra-power-efficient heterogeneous III–V/Si MOSCAP (de-)interleavers for DWDM optical links
Stanley Cheung, Geza Kurczveil, Yingtao Hu, Mingye Fu, Yuan Yuan, Di Liang, and Raymond G. Beausoleil
We discuss the design and demonstration of various III–V/Si asymmetric Mach–Zehnder interferometer (AMZI) and ring-assisted AMZI (de-)interleavers operating at O-band wavelengths with 65 GHz channel spacing. The wafer-bonded III–V/Si metal-oxide-semiconductor capacitor (MOSCAP) structure facilitates ultra-low-power phase tuning on a heterogeneous platform that allows for complete monolithic transceiver photonic integration. The second- and third-order MOSCAP AMZI (de-)interleavers exhibit cross-talk (XT) levels down to -22 dB and -32 dB with tuning powers of 83.0 nW and 53.0 nW, respectively. The one-, two-, and three-ring-assisted MOSCAP AMZI (de-)interleavers have XT levels down to -27 dB, -22 dB, and -20 dB for tuning powers of 10.0 nW, 7220.0 nW, and 33.6 nW, respectively. The leakage current density is measured to be in the range of 1.6–27 μA/cm2. To the best of our knowledge, we have demonstrated for the first time, athermal III–V/Si MOSCAP (de-)interleavers with the lowest XT and reconfiguration power consumption on a silicon platform.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000A22 (2022)
  • DOI:10.1364/PRJ.444991
Four-wave mixing in graphdiyne-microfiber based on synchronized dual-wavelength pulses
Xinxin Jin, Wenli Bao, Han Zhang, Zheng Zheng, and Meng Zhang
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000503 (2022)
  • DOI:10.1364/PRJ.444938
Single-shot three-input phase retrieval for quantitative back focal plane measurement
Mengqi Shen, Qi Zou, Xiaoping Jiang, Fu Feng, and Michael G. Somekh
This paper presents quantitative measurements facilitated with a new optical system that implements a single-shot three-input phase retrieval algorithm. The new system allows simultaneous acquisition of three distinct input patterns, thus eliminating the requirement for mechanical movement and reducing any registration errors and microphonics. We demonstrate the application of the system for measurement and separation of two distinct attenuation measurements of surface waves, namely, absorption and coupling loss. This is achieved by retrieving the phase in the back focal plane and performing a series of virtual optics computations. This overcomes the need to use a complicated series of hardware manipulations with a spatial light modulator. This gives a far more accurate and faster measurement with a simpler optical system. We also demonstrate that phase measurements allow us to implement different measurement methods to acquire the excitation angle for surface plasmons. Depending on the noise statistics different methods have superior performance, so the best method under particular conditions can be selected. Since the measurements are only weakly correlated, they may also be combined for improved noise performance. The results presented here offer a template for a wider class of measurements in the back focal plane including ellipsometry.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000491 (2022)
  • DOI:10.1364/PRJ.445189
All-fiber spatiotemporal mode-locking lasers with large modal dispersion
Huaiwei Zhang, Yunhong Zhang, Jiying Peng, Xinyang Su, Xiaosheng Xiao, Dongjian Xu, Junhao Chen, Tianran Sun, Kai Zheng, Jianquan Yao, and Yi Zheng
It is a challenging problem to balance the modal walk-off (modal dispersion) between multiple transverse modes and chromatic dispersion in long step-index multimode fibers (MMFs). By properly designing the oscillator, we have overcome the difficulty and successfully obtained an all-fiber spatiotemporal mode-locked laser based on step-index MMFs with large modal dispersion for the first time, to our knowledge. Various proofs of spatiotemporal mode-locking (STML) such as spatial, spectral, and temporal properties, are measured and characterized. This laser works at a fundamental frequency of 28.7 MHz, and achieves a pulse laser with single pulse energy of 8 nJ, pulse width of 20.1 ps, and signal-to-noise ratio of ∼70 dB. In addition, we observe a dynamic evolution of the transverse mode energy during the STML establishment process that has never been reported before.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000483 (2022)
  • DOI:10.1364/PRJ.444750
Quantum non-demolition measurement based on an SU(1,1)-SU(2)-concatenated atom-light hybrid interferometer
Gao-Feng Jiao, Keye Zhang, L. Q. Chen, Chun-Hua Yuan, and Weiping Zhang
Quantum non-demolition (QND) measurement is an important tool in the fields of quantum information processing and quantum optics. The atom-light hybrid interferometer is of great interest due to its combination of an atomic spin wave and an optical wave, which can be utilized for photon number QND measurement via the AC-Stark effect. In this paper, we present an SU(1,1)-SU(2)-concatenated atom-light hybrid interferometer, and theoretically study QND measurement of the photon number. Compared to the traditional SU(2) interferometer, the signal-to-noise ratio in a balanced case is improved by a gain factor of the nonlinear Raman process (NRP) in this proposed interferometer. Furthermore, the condition of high-quality QND measurement is analyzed. In the presence of losses, the measurement quality is reduced. We can adjust the gain parameter of the NRP in the readout stage to reduce the impact due to losses. Moreover, this scheme is a multiarm interferometer, which has the potential of multiparameter estimation with many important applications in the detection of vector fields, quantum imaging, and so on.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000475 (2022)
  • DOI:10.1364/PRJ.445858
Sub-terahertz-repetition-rate frequency comb generated by filter-induced instabilities in passive driven fiber resonators
Pan Wang, Jiangyong He, Xiaosheng Xiao, Zhi Wang, and Yange Liu
Ultrahigh-repetition-rate frequency comb generation exhibits great potential in applications of optical waveform synthesis, direct comb spectroscopy, and high capacity telecommunications. Here we present the theoretical investigations of a filter-induced instability mechanism in passive driven fiber resonators with a wide range of cavity dispersion regimes. In this novel concept of modulation instability, coherent frequency combs are demonstrated numerically with rates up to sub-terahertz level. Floquet stability analysis based on the Ikeda map is utilized to understand the physical origin of the filter-induced instability. Comparison with the well-known Benjamin–Feir instability and parametric instability is performed, revealing the intrinsic distinction in the family of modulation instabilities. Our investigations might benefit the development of ultrahigh-repetition-rate frequency comb generation, providing an alternative method for the microresonators.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000465 (2022)
  • DOI:10.1364/PRJ.442615
Topologically protecting squeezed light on a photonic chip
Ruo-Jing Ren, Yong-Heng Lu, Ze-Kun Jiang, Jun Gao, Wen-Hao Zhou, Yao Wang, Zhi-Qiang Jiao, Xiao-Wei Wang, Alexander S. Solntsev, and Xian-Min Jin
Squeezed light is a critical resource in quantum sensing and information processing. Due to the inherently weak optical nonlinearity and limited interaction volume, considerable pump power is typically needed to obtain efficient interactions to generate squeezed light in bulk crystals. Integrated photonics offers an elegant way to increase the nonlinearity by confining light strictly inside the waveguide. For the construction of large-scale quantum systems performing many-photon operations, it is essential to integrate various functional modules on a chip. However, fabrication imperfections and transmission cross talk may add unwanted diffraction and coupling to other photonic elements, reducing the quality of squeezing. Here, by introducing the topological phase, we experimentally demonstrate the topologically protected nonlinear process of four-wave mixing, enabling the generation of squeezed light on a silica chip. We measure the cross-correlations at different evolution distances for various topological sites and verify the nonclassical features with high fidelity. The squeezing parameters are measured to certify the protection of cavity-free, strongly squeezed states. The demonstration of topological protection for squeezed light on a chip brings new opportunities for quantum integrated photonics, opening novel approaches for the design of advanced multi-photon circuits.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000456 (2022)
  • DOI:10.1364/PRJ.445728
Principle and numerical demonstration of high power all-fiber coherent beam combination based on self-imaging effect in a square core fiber
Yuefang Yan, Yu Liu, Haoyu Zhang, Yue Li, Yuwei Li, Xi Feng, Donglin Yan, Jianjun Wang, Honghuan Lin, Feng Jing, Wenhui Huang, and Rumao Tao
The self-imaging effect in a square core fiber has been investigated, and an integrated all-fiber combiner has been proposed based on a large mode area double clad fiber, which can be employed to construct high power coherent beam combining sources in the all-fiber format. The influence of various parameters on beam quality (M2) and efficiency of the all-fiber coherent beam combiner has been studied numerically, which reveals that the near diffraction-limited laser beam can be achieved. A principle demonstration of the self-imaging effect has been carried out experimentally in a square core fiber, which proves the feasibility of beam combining with the square fiber, and that it is a promising way to develop high power coherent beam combination sources.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000444 (2022)
  • DOI:10.1364/PRJ.441384
Time shifting deviation method enhanced laser interferometry: ultrahigh precision localizing of traffic vibration using a urban fiber link
Guan Wang, Zhongwang Pang, Bohan Zhang, Fangmin Wang, Yufeng Chen, Hongfei Dai, Bo Wang, and Lijun Wang
Using a fiber network as a huge sensing system will enrich monitoring methods of public infrastructures and geological disasters. With the traditional cross-correlation method, a laser interferometer has been used to detect and localize the vibration event. However, the random error induced by the cross-correlation method limits the localization accuracy and makes it not suitable for ultrahigh precision localizing applications. We propose a novel time shifting deviation (TSDEV) method, which has advantages over the cross-correlation method in practicability and localization accuracy. Three experiments are carried out to demonstrate the novelty of the TSDEV method. In a lab test, vibration localization accuracy of ∼2.5 m is realized. In field tests, TSDEV method enhanced interferometry is applied to monitor the urban fiber link. Traffic vibration events on the campus road and Beijing ring road have been precisely localized and analyzed, respectively. The proposed technique will extend the function of the existing urban fiber network, and better serve the future smart city.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000433 (2022)
  • DOI:10.1364/PRJ.443019
Silicon nonlinear switch as a conditional circulator for monostatic LiDAR systems
Mingfei Ding, Yiwei Xie, Hao Yan, Abu Naim R. Ahmed, Reza Safian, Swapnajit Chakravarty, Leimeng Zhuang, Pengcheng Jiao, Huan Li, Liu Liu, and Daoxin Dai
All-optical silicon-photonics-based LiDAR systems allow for desirable features in scanning resolution and speed, as well as leverage other advantages such as size, weight, and cost. Implementing optical circulators in silicon photonics enables bidirectional use of the light path for both transmitters and receivers, which simplifies the system configuration and thereby promises low system cost. In this work, to the best of our knowledge, we present the first experimental verification of all-passive silicon photonics conditional circulators for monostatic LiDAR systems using a nonlinear switch. The proposed silicon nonlinear interferometer is realized by controlling signal power distribution with power-splitting circuits, allowing the LiDAR transmitter and receiver to share the same optical path. Unlike the traditional concept requiring a permanent magnet, the present device is implemented by using common silicon photonic waveguides and a standard foundry-compatible fabrication process. With several additional phase shifters, the demonstrated device exhibits considerable flexibility using a single chip, which can be more attractive for integration with photodetector arrays in LiDAR systems.
  • Jan. 21, 2022
  • Photonics Research
  • Vol.10 Issue, 2 02000426 (2022)
  • DOI:10.1364/PRJ.444480
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Deep learning in photonics (2021)


Editor (s): Zongfu Yu, Yang Chai, Li Gao, Darko Zibar

Special Issue on High Power Laser Science and Engineering 2021 (2021)

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