Compensation of dispersion-induced power fading for highly linear radio-over-fiber link using carrier phase-shifted double sideband modulation

ArticleinOptics Letters 36(4):546-8 · February 2011with19 Reads
DOI: 10.1364/OL.36.000546 · Source: PubMed
A carrier phase-shifted (CPS) double sideband (DSB) modulation technique in radio-over-fiber (RoF) system is proposed and experimentally demonstrated. By tuning the biases in a single-drive dual parallel Mach-Zehnder modulator (SD-DPMZM), the optical carrier in the DSB spectrum acquires additional phase shift. The transmittance response of a dispersive RoF link is thus being controlled and shifted in the frequency domain. Experiments successfully turned the maximum transmission frequency to 10 GHz and 15 GHz for both 25 and 39 km fiber links. This is also a highly linear scheme, of which a spurious-free dynamic range (SFDR) of 111.3 dB·Hz<sup>2/3</sup> is experimentally obtained.
    • "The transfer function of a dispersive fiber link with a length of L is given as [13] ( "
    [Show abstract] [Hide abstract] ABSTRACT: An analog photonic link with the compensation of the dispersion-induced power fading is proposed and demonstrated based on phase modulation to intensity modulation conversion in a Sagnac loop. Due to the velocity mismatch of the modulator, only the incident light wave along the clockwise direction is effectively modulated by the radio frequency signals, while the counterclockwise light wave is not modulated. After combining the two light waves in a polarizer, an intensity modulated optical signal is generated, which can be directly detected. In addition, the phase difference between the two light waves can be adjusted through the polarization controller before the polarizer. This feature is used to shift the frequency response of a dispersive link to compensate the dispersion-induced power fading at any working frequency. Experimental results show that the power fading after transmission over both 25 and 50 km lengths of fiber in a conventional intensity modulated link can be successfully compensated in the proposed link, and thus, a high and constant link gain over a large frequency range is achieved. The spur-free dynamic ranges of the link before and after fiber transmission are also measured.
    Full-text · Article · Jul 2015
    • "However, the optical DSB signal is susceptible to the fiber dispersion that induces different phase shifts to the two sidebands and subsequently leads to power fading of the received RF signals [9]. Much work has been carried out to overcome this fiber dispersion effect, where the most straightforward technique aims to remove one spectral component, including the single sideband (SSB) and optical carrier suppression (OCS) modulation schemes [5,6,9101112. OCS has an inherent advantage in power balance between two sidebands which leads to a sensitivity improvement. However, this technique requires a large RF drive power to obtain a desirable modulation depth as the modulator works in the nonlinear region [5]. "
    [Show abstract] [Hide abstract] ABSTRACT: In this paper, we investigate the optimal carrier-to-sideband ratio (CSR) for optical double-sideband (DSB) signals in radio-over-fiber (RoF) transmission. A pre-distortion method based on spectral shaping is proposed to optimize the signal CSR and eliminate the dispersion-induced power fading. A 12 GHz RoF transmission over 29 km standard single mode fiber (SSMF) is experimentally demonstrated which reveals that pre-distorted DSB has a 4.4 dB improvement over the one without pre-distortion, and 1.2 dB sensitivity advantage over single sideband (SSB) both with optimal CSR. The pre-distortion method is also applied to multi-channel transmission. The multi-channel experiment shows that for all channels the dispersion-induced power fading effects can be simultaneously mitigated and the pre-distorted DSB signals have ~1 dB sensitivity improvement over the SSB signals.
    Full-text · Article · Feb 2014
    • "The microwave powers are measured, compared and used to estimate the microwave frequency in a post-processing stage. Mathematically, when a lightwave is sent to a DPMZM-based link, the output signal of the DPMZM is written as [11] (1) 1531-1309 © 2013 IEEE where and are the amplitude and angular frequency of the lightwave, is the modulation index of MZM1, is the phase bias of MZM3, and are the angular frequency and amplitude of the RF signal, and are the half-wave voltages of MZM1 and MZM3, is the offset voltage when . To obtain (1), small-signal modulation is assumed, i.e., . "
    [Show abstract] [Hide abstract] ABSTRACT: A novel microwave frequency measurement scheme based on a dual-parallel Mach-Zehnder modulator (DPMZM) is proposed and demonstrated. By simply adjusting the bias voltage of the DPMZM, the measurement range can be divided into several parts and each part has very high resolution. Thus, the system can be used in a two-stage instantaneous frequency measurement scheme, in which the first stage coarsely determines the frequency band of the intercepted microwave signal, and then the proposed scheme measures the frequency with high resolution. An experiment is performed. Instantaneous frequency measurement with a frequency measurement range of 2.3-18.7 GHz and a measurement resolution of ±0.20 GHz is achieved.
    Full-text · Article · Nov 2013
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