A High Spur-Free Dynamic Range Silicon DC Kerr Ring Modulator for RF Applications

Improving the Linearity of Silicon Ring Modulators by Manipulating the Photon Dynamics

“…However, ultimate SFDRs in [28] and [29] are inferior to our device as a result of their high Q factors. Though the ring modulator in [30] utilizes the predistortion to further improve the linearity, it needs a complex external predistortion circuit whose bandwidth requires higher than the highest harmonic generated by the predistorter. We want to stress that different linearization techniques in Table. 1 can be combined so as to generate a silicon ring modulator with ultrahigh linearity.…”

“…We note that almost all linearity measurements of ring modulators are performed at frequencies lower than 10 GHz [24], [28]- [30]. However, for many wideband MWP systems, frequencies of RF signals can reach dozens of Gigahertz.…”

“…A linear silicon ring modulator thus is demonstrated with a SFDR of 103.6 dB•Hz 2/3 at 1.2 GHz. To further increase the linearity, based on the previous work [29], the SFDR is improved to 108 dB•Hz 2/3 by the method of predistortion [30]. However, the cost is that its modulation efficiency degrades to 7 pm/V.…”

Modulation Linearity Characterization of Si Ring Modulators

“…The bias voltage of -2V is used because with a smaller bias voltage the PN junction in the RM can reach the forward bias region resulting in clipping when RF modulated, and with a larger bias voltage there is a danger of junction breakdown for the RM when RF modulated. In addition, the Si RM SFDR does not strongly depend on the bias voltage [22] as long as the PN junction in the RM does not reach the forward bias region or breakdown when RF When in is smaller than res, which is the case for Point A, the lower sidebands have smaller peak values than the upper sidebands as can be seen in Fig. 8(b) and (d).…”

“…However, the accuracy of the model is not verified with experimental results. In [22], the Si RM is linearized with the DC Kerr effect in the p-i-n phase shifter and the influence of the bias voltage and the input optical wavelength on the performance is investigated. However, with Taylor series expansion of the Si RM transfer function, very complex analytic expressions are needed for determining distorted signals, which may reduce its applicability to a wider range of Si RM applications.…”