Experimental demonstration of a balanced electroabsorption modulated microwave photonic link

Abstract

A novel balanced electroabsorption modulated photonic link for simultaneous suppression of even-order distortions, third-order distortions, laser relative intensity noise (RIN), and common amplified spontaneous emission noise at the same modulator bias point was experimentally demonstrated for the first time. By biasing the balanced electroabsorption modulator at the thirdorder null, the third-order distortions were suppressed, while the balanced link architecture suppressed all even-order distortions and common mode noises. The fabricated balanced electroabsorption modulator (B-EAM) showed well-matched dc characteristics in terms of-and transfer curve. System experiments were performed to compare Single-EAM and BEAM links. In the BEAM link, 2-dB suppression of laser RIN and 20-dB improvement in spurious free dynamic range over the single-EAM link were observed.

Simulative investigation the impact of optical amplification techniques on single- and dual-electrode MZM and direct modulator's in single-tone RoF system

“…Recently, two balanced systems with one wavelength and two fibers and two wavelengths and one fiber were demonstrated to suppress second-order HD (HD2) and second-order intermodulation distortion (IMD2) and improve dynamic range in a RoF system [6][7]. The balanced system that utilizes one wavelength and two fibers, in which two EAMs have mirrored transfer functions, is very difficult to maintain balance between two fiber transmissions, resulting in less suppression of HD2 and IMD2.…”

“…The balanced system that utilizes one wavelength and two fibers, in which two EAMs have mirrored transfer functions, is very difficult to maintain balance between two fiber transmissions, resulting in less suppression of HD2 and IMD2. Also, a feedback control system is required to maintain balance [6]. Later, this technique was improved by using two wavelengths and one fiber for each RoF system [7], which is referred to as the conventional balanced system in this letter.…”

Class-B Microwave-Photonic Link Using Optical Frequency Modulation and Linear Frequency Discriminators

“…Previously demonstrated methods for suppressing intensity noise using balanced detection [6] also use two links: one for each of the two outputs of a dual-output MZ. The two optical paths must be matched to a small fraction of the RF wavelength.…”

“…Common-mode intensity noise (that is present at the input to a modulator) can be suppressed, e.g., [6], using a dualoutput MZ, two transmission fibers, and balanced differential detection. However, the degree of intensity noise suppression is limited as the modulation index increases [7], the shot noise (uncorrelated in the two detectors) is not reduced, and the intensity noise added after the modulator (e.g., signal-spontaneous beat noise from an optical amplifier) is not suppressed.…”

Noise Reduction in Class-AB Microwave-Photonic Links

“…Common-mode RIN can be cancelled using a balanced photodetector [10], but this does not affect the other challenges associated with the large residual carrier. Low-bias techniques have been explored in which a Mach-Zehnder (MZ) is operated at lower bias than the conventional quadrature bias (Q-bias or QB) point (50% transmission).…”