Silicon Mach-Zehnder Modulator Research Articles

Performance evaluation of photonic UWB generation based on silicon MZM

Silicon photonics has emerged as the premier candidate for the photonic systems-on-chip (SoC). The scheme based on the silicon Mach-Zehnder modulator (MZM) to generate photonic ultra-wideband (UWB) signals is helpful to the integration of the UWB system with other optical networks on a single silicon-based chip. In this paper, according to the influence of the nonlinear free carrier dispersion (FCD) effect and the free carrier absorption (FCA) effect, the performance of two typical UWB generation schemes is numerically analyzed. The double side-band UWB (DSB-UWB) generation scheme needs the DC reverse bias which increases the complexity of the modulator and there is a residual chirp resulting from the FCD effect even the push-pull operation is adopted. The quasi single-sideband UWB (QSSB-UWB) generation scheme doesn't have these problems. However there is the asymmetric amplitude peak in the generated UWB signal. The property of the large singal modulation is also investigated to improve the signal-to-noise ratio (SNR).

High-speed low-voltage single-drive push-pull silicon Mach-Zehnder modulators

We demonstrate a single-drive push-pull silicon Mach-Zehnder modulator (MZM) with a π-phase-shift voltage of 3.1 V and speed up to 30 Gb/s. The on-chip insertion loss is 9 dB due to the use of a 6 mm-long phase shifter. Higher switching speed up to 40-50 Gb/s is also demonstrated in devices with shorter phase shifters which require higher drive voltages but have lower insertion losses.

125-Gb/s operation with 029-V·cm V_πL using silicon Mach-Zehnder modulator based-on forward-biased pin diode

We present high-speed operation of pin-diode-based silicon Mach-Zehnder modulators that have side-wall gratings on both sides of the waveguide core. The use of pre-emphasis signals generated with a finite impulse response digital filter was examined in the frequency domain to show how the filter works for different filter parameter sets. In large signal modulation experiments, V(π)L as low as 0.29 V·cm was obtained at 12.5 Gb/s using a fabricated modulator and the pre-emphasis technique. Operation of up to 25-Gb/s is possible using basically the same driving configurations.

Silicon Mach-Zehnder modulator of extinction ratio beyond 10 dB at 100-125 Gbps

Silicon Mach-Zehnder modulators with reduced series resistance in lateral PN junction rib-waveguide phase shifters for enhanced high-speed response are fabricated and characterized. Extinction ratio higher than 10 dB is obtained at 10.3-11.7 Gbps with mask margins of 27% (10.3-Gbps 10GBE), 16% (10.7-Gbps STM-64/OC-192) and 10% (11.3-Gbps STM-64/OC-192) in eye-diagram measurements incorporating mask tests using a RF cut-off filter. In unfiltered eye-diagram measurements without mask tests, extinction ratio higher than 13 dB is obtained at 10.0-12.5 Gbps. The silicon modulators reveal high-speed performance comparable with that of lithium-niobate modulators in high-speed optical fiber telecommunications.

Broadband linearized silicon modulator

A scheme to achieve a wideband linearized silicon Mach-Zehnder (MZ) modulator is proposed. The modulator consists of a single MZ interferometer with identical reverse-biased silicon diode phase shifters in both arms, driven in a push-pull configuration. It is shown that the 3rd order nonlinearity of the modulator can be eliminated by canceling the nonlinearities from the silicon phase shifters and the MZ transfer function against each other. The 2nd order nonlinearity is simultaneously eliminated by differential detection or operation away from the quadrature point. As a result, the linearity of the proposed silicon modulator greatly exceeds the linearity of a conventional MZ modulator with ideal, linear (e.g. LiNbO3) phase shifters. The simplicity and large optical and RF bandwidth of the proposed modulator make it attractive for analog photonic applications.

混合硅调制器

A number of active elements have been demonstrated using the hybrid silicon evanescent platform, including lasers, amplifiers, and detectors. In this letter, two types of hybrid silicon modulators, fulfilling the building blocks in optical communication on this platform, are presented. A hybrid silicon electroabsorption modulator, suitable for high speed interconnects, with 10-dB extinction ratio at -5 V and 16-GHz modulation bandwidth is demonstrated. In addition, a hybrid silicon Mach-Zehnder modulator utilizing carrier depletion in multiple quantum wells is proved with 2 Vmm voltage-length product, 150-nm optical bandwidth, and a large signal modulation up to 10 Gb/s.

RF Frequency Doubling Using a Silicon p-i-n Diode-Based Mach–Zehnder Modulator

We demonstrate frequency doubling at 1 GHz using a new silicon Mach-Zehnder modulator (MZM). Modulation of the refractive index of silicon for an MZM action is achieved via the injection/depletion of electrons and holes in a p-i-n diode. The silicon MZM used in the experiment shows high phase-shift efficiency and a VpiLpi of 1.88times10-2Vldrcm which is nearly 350 times smaller than those of previously reported LiNbO3-based MZM. Also, a theoretical analysis of frequency doubling in the time domain shows good agreement with the experimental results.

Effect of carrier lifetime on forward-biased silicon Mach-Zehnder modulators

We present a systematic study of Mach-Zehnder silicon optical modulators based on carrier-injection. Detailed comparisons between modeling and measurement results are made with good agreement obtained for both DC and AC characteristics. A figure of merit, static VpiL, as low as 0.24Vmm is achieved. The effect of carrier lifetime variation with doping concentration is explored and found to be important for the modulator characteristics.