scholarly journals RF-DC conversion efficiency improvement for microwave transmission with pulse modulation

2019 ◽  
Vol 6 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Takashi Hirakawa ◽  
Ce Wang ◽  
Naoki Shinohara
Keyword(s):  
Conversion Efficiency ◽  
Continuous Wave ◽  
Harmonic Balance Method ◽  
Transmission Efficiency ◽  
Duty Ratio ◽  
Necessary Condition ◽  
Pulse Modulation ◽  
Microwave Transmission ◽  
Output Load ◽  
Modulated Waves

Microwave power transfer (MPT) can solve certain types of problems. For example, Internet of Things requires a flexible configuration of sensor networks, which is hindered by wired-charging sensors. This problem can be overcome by MPT techniques. However, the transmission efficiency of MPT is lower than that of wired transmission. This study focuses on the operation of rectifiers having a pulse-modulated input signal. Although a pulse-modulated wave is effective for improving the RF-DC conversion efficiency, the output voltage waves of rectifiers have a high ripple content. Moreover, the harmonic balance method cannot be used to simulate the operation of a pulse-modulated rectifier. To reduce the ripple content, a smoothing capacitor should be connected in parallel to an output load. We investigated the influence of a smoothing capacitor, the general characteristics of rectifiers under pulse-modulated waves, and the effectiveness of using pulse-modulated waves for improving RF-DC conversion efficiency. In conclusion, we reveal a necessary condition of the smoothing capacitor for improvement, demonstrate the effectiveness of pulse modulation, and show that the optimum impedance with a pulse-modulated wave input is an inverse of duty ratio times as compared to that with continuous wave input.

scholarly journals 1.5-W 520 nm Continuous-wave Output from a 50μm/0.22NA Fiber-Coupled Laser Diode Module

2021 ◽  
Author(s):  
Bojie Lou ◽  
Bing Ding ◽  
Zhangwang Miao ◽  
Pengfei Zhao ◽  
Haijuan Yu ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Continuous Wave ◽  
Numerical Aperture ◽  
Experimental Result ◽  
Optical Conversion Efficiency ◽  
Core Diameter ◽  
Central Wavelength ◽  
High Brightness ◽  
Optical Conversion ◽  
Final Output

Abstract In this paper, a high brightness fiber-coupled module with a central wavelength of 520nm is simulated and designed by ray-tracing software ZEMAX, and then is experimentally implemented. Three 1-w continuous-wave green LD single emitters based on TO-9-package are successively collimated, spatially combined, and focused into an optical fiber with a core diameter of 50 μm and a numerical aperture of 0.22. The final output power of 1.53w is obtained, corresponding to an optical-optical conversion efficiency of 51% and an electro-optical conversion efficiency of 10%, and the tolerance between the simulation and the experimental result is analyzed and explained.

Investigation of Conversion Efficiency of Widely Tunable Continuous-Wave Mid-IR Difference Frequency Generation Fiber-type Laser

2008 ◽  
Vol 28 (2) ◽  
pp. 295-300
Author(s):  
蒋建 Jiang Jian ◽  
李晓芹 Li Xiaoqin ◽  
冯素娟 Feng Sujuan ◽  
王执山 Wang Zhishan ◽  
毛庆和 Mao Qinghe ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Continuous Wave ◽  
Fiber Type ◽  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Frequency Generation

Optimal Conversion Efficiency of Continuous-Wave Optical Parametric Oscillator

2016 ◽  
Vol 43 (10) ◽  
pp. 1001011
Author(s):  
姜洪波 Jiang Hongbo ◽  
沈利沣 Shen Lifeng ◽  
赵志刚 Zhao Zhigang ◽  
刘斌 Liu Bin ◽  
项震 Xiang Zhen ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Optical Parametric Oscillator ◽  
Continuous Wave ◽  
Parametric Oscillator ◽  
Optical Parametric

Isomorphism Detection of Planar Kinematic Chains With Multiple Joints Using Information Theory

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Rajneesh Kumar Rai ◽  
Sunil Punjabi
Keyword(s):  
Information Theory ◽  
Structural Similarity ◽  
Transmission Efficiency ◽  
Necessary Condition ◽  
Connectivity Matrix ◽  
Kinematic Chains ◽  
Compact Size ◽  
Independent Loops ◽  
Link Connectivity ◽  
Structural Invariants

Isomorphism (structural similarity) of kinematic chains (KCs) of mechanisms is an important issue in the structural synthesis, which must be identified to avoid the duplicate structures. Duplication causes incorrect family size, i.e., distinct KCs with a given number of links (n) and degree of freedom (dof). Besides simple joints kinematic chains (SJKCs), multiple joints kinematic chains (MJKCs) are also widely used because of their compact size and the methods dealing with such KCs are few. The proposed method deals with two different structural invariants, i.e., primary structural invariants (provide only the necessary condition of isomorphism), such as link connectivity number (LCN) of all the links, link connectivity number of chain (CCN), joint connectivity number (JCN) of all the joints, and joint connectivity number of chain (JCNC), and secondary structural invariants (provide the sufficient condition of isomorphism), such as power transmission (P) and transmission efficiency (Te). Primary structural invariants are calculated using a new link–link connectivity matrix (LLCM), whereas secondary structural invariants are calculated using the concept of entropy of information theory. The method has been successfully tested for 10 and 11 links MJKCs (illustrative examples taken in the paper) and for the families of 18 MJKCs with 8 links, 2 MJs, 1-dof, and 3 independent loops; 22 MJKCs with 8 links, 1 MJ, 1-dof, and 3 independent loops; and 83 MJKCs with 9 links, 1 MJ, 2-dof, and 3 independent loops.

Continuous-wave fiber optical parametric wavelength converter with +40-dB conversion efficiency and a 38-dB noise figure

2003 ◽  
Vol 28 (9) ◽  
pp. 692 ◽  
Author(s):  
Kenneth K. Y. Wong ◽  
Katsuhiro Shimizu ◽  
Michel E. Marhic ◽  
Katsumi Uesaka ◽  
Georgios Kalogerakis ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Continuous Wave ◽  
Noise Figure ◽  
Wavelength Converter ◽  
Optical Parametric ◽  
Fiber Optical

COMPARISON OF INTERCHANNEL FOUR-WAVE MIXING WITH CONTINUOUS WAVES, QUASI-CONTINUOUS WAVES AND ULTRASHORT PULSES

2003 ◽  
Vol 12 (03) ◽  
pp. 377-384 ◽  
Author(s):  
SHIMING GAO ◽  
CHANGXI YANG ◽  
GUOFAN JIN
Keyword(s):  
Conversion Efficiency ◽  
Wavelength Division Multiplexing ◽  
Pulse Width ◽  
Continuous Wave ◽  
Ultrashort Pulses ◽  
Four Wave Mixing ◽  
Wave Mixing ◽  
Propagation Length ◽  
Wavelength Division ◽  
Continuous Waves

We compare the interchannel four-wave mixing (FWM) in dense wavelength division multiplexing (DWDM) systems with continuous waves, quasi-continuous waves and ultrashort pulses. The differences are theoretically analyzed for the three inputs. We investigate the FWM conversion efficiency as a function of the channel spacing, the fiber length, the single bit energy and the pulse width. It is shown that the FWM effect in DWDM systems with quasi-continuous waves is the strongest and with ultrashort pulses is the lowest among the three cases. The FWM conversion efficiency changes periodically with the propagation length, and it is approximately an exponential function of the single bit energy. The performance of the pulse FWM effect versus the pulse width is different from that of the quasi-continuous wave FWM, which may be one possible way to suppress the interchannel FWM.

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