Octagonal polarization-maintaining supermode fiber for mode division multiplexing system

A method which utilizes a Kerr phase-interrogator to measure the group birefringence dispersion (GBD) of a polarization-maintaining fiber (PMF) is systematically studied in this paper. The differential group delay of two sinusoidally modulated optical signals (SMOSs) polarized along the principal axes of the PMF is measured by a Kerr phase-interrogator, which leads to the group birefringence of the PMF. As the laser wavelength of the SMOSs varies, the group birefringence as a function of the laser wavelength is obtained, and the GBD is calculated as the derivative of the group birefringence with respect to the laser wavelength. The proposed method is experimentally demonstrated by characterizations of a Panda PMF with high GBD and an elliptical core PMF with low GBD, and its performance is analyzed. The proposed method eliminates the impact of the laser coherent length and allows for characterizing the GBD of PMFs that are tens of kilometers long.

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A 2 × 20 Gbps hybrid MDM-OFDM–based high-altitude platform-to-satellite FSO transmission system

Journal of Optical Communications ◽

10.1515/joc-2020-0075 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Vel Murugan Gomathy ◽

T. V. Paramasivam Sundararajan ◽

C. Sengodan Boopathi ◽

Pandiyan Venkatesh Kumar ◽

Krishnamoorthy Vinoth Kumar ◽

...

Keyword(s):

High Altitude ◽

Orthogonal Frequency Division Multiplexing ◽

High Speed ◽

Satellite Communication ◽

Input Power ◽

Transmission System ◽

Communication Link ◽

Space Optics ◽

High Altitude Platform ◽

Mode Division Multiplexing

AbstractIn the present study, the application of free space optics (FSO) transmission system to realize a long-reach high-altitude platform (HAP)-to-satellite communication link has been exploited. High-speed information transmission without interference is accomplished using orthogonal frequency division multiplexing (OFDM). Further, the information capacity of the proposed system is increased by employing mode division multiplexing (MDM). We have investigated the proposed MDM-OFDM-HAP-to-satellite FSO transmission system performance over varying FSO range, diameter of the receiver, pointing errors, and input power. Also, an improved transmission performance of the proposed system using a square root module is reported.

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40 Gb/s High-speed mode-division multiplexing transmission employing NRZ modulation format

Journal of Optical Communications ◽

10.1515/joc-2019-0251 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Rabiu Imam Sabitu ◽

Nafizah Goriman Khan ◽

Amin Malekmohammadi

Keyword(s):

System Performance ◽

High Speed ◽

Direct Detection ◽

Signal To Noise Ratio ◽

Optical Signal ◽

Threshold Power ◽

Modulation Format ◽

Transmission Distance ◽

Mode Division Multiplexing ◽

Speed Mode

AbstractThis report examines the performance of a high-speed MDM transmission system supporting four nondegenerate spatial modes at 10 Gb/s. The analysis adopts the NRZ modulation format to evaluate the system performance in terms of a minimum power required (PN) and the nonlinear threshold power (PTH) at a BER of 10−9. The receiver sensitivity, optical signal-to-noise ratio, and the maximum transmission distance were investigated using the direct detection by employing a multimode erbium-doped amplifier (MM-EDFA). It was found that by properly optimizing the MM-EDFA, the system performance can significantly be improved.

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A Highly Birefringent Photonic Crystal Fiber for Terahertz Spectroscopic Chemical Sensing

Sensors ◽

10.3390/s21051799 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1799

Author(s):

Tianyu Yang ◽

Liang Zhang ◽

Yunjie Shi ◽

Shidi Liu ◽

Yuming Dong

Keyword(s):

Photonic Crystal ◽

Photonic Crystal Fiber ◽

Chemical Sensing ◽

Numerical Aperture ◽

Wide Band ◽

Relative Sensitivity ◽

Chemical Sensitivity ◽

High Birefringence ◽

Crystal Fiber ◽

Polarization Maintaining

A photonic crystal fiber (PCF) with high relative sensitivity was designed and investigated for the detection of chemical analytes in the terahertz (THz) regime. To ease the complexity, an extremely simple cladding employing four struts is adopted, which forms a rectangular shaped core area for filling with analytes. Results of enormous simulations indicate that a minimum 87.8% relative chemical sensitivity with low confinement and effective material absorption losses can be obtained for any kind of analyte, e.g., HCN (1.26), water (1.33), ethanol (1.35), KCN (1.41), or cocaine (1.50), whose refractive index falls in the range of 1.2 to 1.5. Besides, the PCF can also achieve high birefringence (∼0.01), low and flat dispersion, a large effective modal area, and a large numerical aperture within the investigated frequency range from 0.5 to 1.5 THz. We believe that the proposed PCF can be applied to chemical sensing of liquid and THz systems requiring wide-band polarization-maintaining transmission and low attenuation.

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