scholarly journals Irregular Shifting of RF Driving Signal Phase to Overcome Dispersion Power Fading

Photonics ◽  
2019 ◽  
Vol 6 (4) ◽  
pp. 104 ◽  
Author(s):  
Febrizal Ujang ◽  
Teguh Firmansyah ◽  
Purnomo S. Priambodo ◽  
Gunawan Wibisono
Keyword(s):  
Chromatic Dispersion ◽  
Modulation Scheme ◽  
Rf Power ◽  
Signal Phase ◽  
Optical Wavelength ◽  
Optical Single Sideband ◽  
Mach Zehnder Modulator ◽  
Bias Point ◽  
Driving Signal ◽  
Better Than

The main problem with the radio-over-fiber (RoF) link is the decrease in the recovered radio frequency (RF) power due to the chromatic dispersion of the fiber known as dispersion power fading. One of the methods for dealing with dispersion power fading is to use the optical single sideband (OSSB) modulation scheme. The OSSB modulation scheme can be generated by biasing the dual-drive Mach–Zehnder modulator (DD-MZM) to the quadrature bias point (QBP) and shifting the RF drive signal phase (θ) by 90°, which is called the regular θ. However, the OSSB modulation scheme only overcomes dispersion power fading well at the modulation index (m) < 0.2. This paper proposes an irregular θ method to overcome dispersion power fading at all m. There are two irregular θ for every m used. The irregular θ managed to handle dispersion power fading better than OSSB modulation scheme did at every m. Specifically, the irregular θ could handle the dispersion power fading well at m ≤ 1. In sum, the irregular θ could overcome the dispersion power fading at any RF frequency and optical wavelength without having to re-adjust the transmitter.

scholarly journals Generation of Switchable Chirp Waveforms in the Photonic Domain with Immunity to Dispersion-Induced Power Fading

Photonics ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 501
Author(s):  
Chaoqun Huang ◽  
Jun Ou ◽  
Hao Chi
Keyword(s):  
Bias Voltage ◽  
Chromatic Dispersion ◽  
Radio Over Fiber ◽  
Rf Power ◽  
Optical Filtering ◽  
Polarization Control ◽  
Mach Zehnder Modulator ◽  
The Stability ◽  
Rf Signal ◽  
The Given

A novel photonic approach to generating switchable multi-format chirp waveforms using a dual-drive dual-parallel Mach–Zehnder modulator (DD-DPMZM) is proposed and experimentally demonstrated. By properly controlling the bias voltage on the DD-DPMZM, different chirp RF waveforms, including the dual-, down-, and up-chirp waveforms, can be obtained when an RF signal and a chirp RF signal are injected into the modulator. A main feature of this approach is that it can eliminate chromatic dispersion-induced RF power fading, which is highly desired in distributed multi-functional radars based on radio over fiber. There is no polarization control and optical filtering in the given scheme, which also improves the stability and feasibility of the approach. An experiment successfully demonstrated the generation and switching of the multi-format chirp waveforms and the capability of immunity to dispersion-induced power fading.

scholarly journals Asymmetric Carrier Divider with an Irregular RF Phase on DD-MZ Modulator for Eliminating Dispersion Power Fading in RoF Communication

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 106
Author(s):  
Gunawan Wibisono ◽  
Febrizal Ujang ◽  
Teguh Firmansyah ◽  
Purnomo S. Priambodo
Keyword(s):  
High Efficiency ◽  
Modulation Scheme ◽  
Direct Signal ◽  
Model And Simulation ◽  
Deviation Factor ◽  
Optical Single Sideband ◽  
Bias Point ◽  
Rf Signal ◽  
The Impact ◽  
The Mathematical Model

The main problem of intensity modulation (IM) in radio-over-fiber (RoF) communication is dispersion power fading (DPF), which occurs when the signal is transmitted through a dispersive link that causes a sideband cancelation effect. The DPF level of the RoF link is determined by the deviation factor (DF). The optical single-sideband (OSSB) modulation scheme, which is generated by driving one of the dual-drive Mach–Zehnder modulators (DD-MZMs), is usually used to overcome DPF. The DF value of OSSB modulation at modulation index m = 0.1 increases from 0.008 to 0.930 at m = 1. It can be said that this method is only effective at reducing DF at low m. However, as well-known information of the DD-MZM system, high-efficiency optic–electric conversions can be obtained at high m values, but DF will increase. Therefore, reducing the DPF value for high m ≥ 0.1 is interesting. It is known that in wireless communication, to reduce the impact of fading, direct signals are amplified and signals with irregular phases are used. Moreover, this paper proposes the DD-MZM with an asymmetric carrier divider as a direct signal and combines it with an irregular radio frequency (RF) phase to reduce the DPF at high m. The carrier that is generated by laser diode (LD) power (PIN) is divided asymmetrically as power modulation (PDD-MZM) and carrier arm (CA) power (PCA). Furthermore, the minimum DF is obtained when the PIN is separated as 75% for PCA and 25% for PDD-MZM with an irregular RF signal of θ = 48° and a bias point value of γ = ¾. As a result, with the same power as OSSB, this proposed structure produces DF at m = 0.1 and m = 1 with values of 0.008 and 0.03, or it can reduce DF of 96.7% at m = 1. The mathematical model and simulation model have very good agreement, which validates the proposed method.

Generation of Frequency 12-Tupling Millimeter-Wave Using one DPMZM to Overcome Chromatic Dispersion

2015 ◽  
Vol 713-715 ◽  
pp. 1184-1187
Author(s):  
Dong Liang ◽  
Qing Gui Tan ◽  
Wei Jiang ◽  
Xiao Jun Li ◽  
Zhong Bo Zhu
Keyword(s):  
Millimeter Wave ◽  
Chromatic Dispersion ◽  
Wave Generation ◽  
Time Shift ◽  
Power Penalty ◽  
Eye Diagram ◽  
Baseband Signal ◽  
Mach Zehnder Modulator ◽  
Theoretical Analyses

In this paper, a approach for frequency 12-tupling millimeter-wave generation using one DPMZM (Dual-Parallel Mach-Zehnder Modulator) to overcome chromatic dispersion is demonstrated. The millimeter-wave with the baseband signal carried only by minus 6-th order sideband is generated by properly adjusting a series of parameters. As the signal transmittes along the fiber, there is no time shift caused by chromatic dispersion. Theoretical analyses and simulated results show that when the optical mm-wave carrying 2.5Gbps baseband signal transmits over 55 Km, the eye diagram still keeps open and clear. The power penalty is about 0.7 dB after transmits over 40 Km.

A photonic transmission link with enhanced dynamic range by incorporating phase shifters in dual drive dual parallel Mach–Zehnder modulator

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sarika Singh ◽  
Sandeep K. Arya ◽  
Shelly Singla ◽  
Pulkit Berwal
Keyword(s):  
Dynamic Range ◽  
Control Method ◽  
Phase Shifters ◽  
Optical Modulator ◽  
Rf Signals ◽  
Single Sideband Modulation ◽  
Spurious Free Dynamic Range ◽  
Optical Single Sideband ◽  
Mach Zehnder Modulator ◽  
Free Dynamic

Abstract A linearization scheme is proposed for microwave photonic link to enlarge spurious free dynamic range using a dual-electrode dual parallel Mach–Zehnder modulator (MZM). This scheme employs phase control method to improve performance of the link by adjusting phase of radio frequency (RF) signals and bias voltages of optical modulator. Optical single sideband modulation is achieved through sub-modulators of dual parallel MZM which increases efficiency of the link. The simulated results show that third order intermodulation distortion is suppressed by 28 dB when the input RF signals are 9.1 and 9.5 GHz and noise floor is at −161 dBm/Hz. The spurious free dynamic range is also improved by 12.6 dB.

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