Modeling and bandwidth optimization of microring resonator modulators with phase ring enhancements

Abstract

The modeling of microring resonator modulators with phase rings is presented. The phase ring effect and the bandwidth optimization are studied by using the proposed model. Results show that the phase ring can enhance the modulation effectively. It also causes modulation resonances which worsens the modulation performances. Resonators with double phase rings keep the coupling region symmetric and have good phase enhancement ability. The amplitude of the modulated signal can be increased substantially while the phase rings are optimized by setting the operating point at the resonance point.

A high-speed electro-optic triple-microring resonator modulator

“…The peak-to-peak voltage of the NRZ pulse train is 2.0 V. It can be seen that the amplitudes of the output lights for both signal rates are almost same. The extinction ratio is 20 dB, which is superior to the reported value in previous coupling intensity modulated MZIMR 11 , 20 . In both pulse responses, small oscillations are seen at the rising edge of the signals.…”

“…4, the oscillations and resonance points are observed over 160 GHz. Such limitation is similar to that exists in the phase ring enhanced MZIMR 1, 20 . Note that, taking into account the roll-off effect mentioned above, the frequency at a resonance point is not exactly an integer multiple of the FSR.

Figure 3Modulated output signals of the resonator.

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“…The maximum modulation depth is found to be 0.23 or 6.4 dB. Such modulation depth is larger than that reported for MZIMR and comparable to the phase ring enhanced MZIMR 20 . In Fig.…”

“…Though MZIMR theoretically predicted an unlimited bandwidth property 14 – 18 , the frequency limitation in our modulator presumably results from the index modulation in ring 3. It leads to the roll-off in the modulation depth at very high modulation frequencies because the sidebands diminish with increasing modulation frequency 15 , 20 . When the frequency increases close to an integer multiple of the free spectra rang (FSR), the modulation causes a significant decrease to the circulating field in the cavity 16 .…”

“…These devices exhibited a high extinction and ultra-high speed response to the driving signal. This method has been further investigated for optimization 20 . Potentially, both the modulation speed and signal extinction can be further increased by using an optimized energy feedback mechanism with a greater storing effective energy and constant optical power.…”