We demonstrate binary phase shift keying(BPSK) modulation using a silicon Mach–Zehnder modulator with aπ-phase-shift voltage(Vπ) of-4.5 V.The single-drive push–pull traveling wave electrode has been optimized using numerical simulations with a 3 dB electro-optic bandwidth of 35 GHz.The 32 Gb/s BPSK constellation diagram is measured with an error vector magnitude of 18.9%.
We report a compact 2 × 2 Mach–Zehnder interferometer(MZI) electro-optic switch fabricated on a siliconon-insulator using standard complementary metal-oxide semiconductor(CMOS) processes. With a short modulation arm length of 200 μm, the crosstalk is reduced to-22 d B by the new modulation scheme of push–pull modulation with a pre-biased π∕2 phase shift. The new modulation scheme can also work with a fast switching time of about 5.4 ns.
We experimentally demonstrate a 4 × 4 nonblocking silicon thermo-optic(TO) switch fabric consisting of three stages of tunable generalized Mach–Zehnder interferometers. All 24 routing states for nonblocking switching are characterized. The device's footprint is 4.6 mm × 1.0 mm. Measurements show that the worst cross talk of all switching states is-7.2 dB. The on-chip insertion loss is in the range of 3.7–13.1 dB. The average TO switching power consumption is 104.8 mW.
We explore all-optical wavelength conversion in a microdisk resonator integrated with interleaved p-n junctions.Numerical simulation based on temporal coupled mode theory is performed to study the free-carrier dynamics inside the cavity.It reveals that the detuning of pump and probe frequencies and the carrier lifetime have a significant effect on the device performance.Experimental result confirms that the conversion speed can be considerably improved by applying a reverse bias on the p-n junctions.Wavelength conversion at 10 Gb/s data rate is achieved with a pump power of 5.41 dBm and a bias voltage of-6 V.
We systematically investigate the influences of the input infrared spectrum, chirp, and polarization on the emitted intense terahertz spectrum and spatial dispersion in lithium niobate via optical rectification. The terahertz yield and emission spectrum depend on both the chirp and spectrum of the input pump laser pulses. We also observe slight non-uniform spatial dispersion using a knife-edge measurement, which agrees well with the original predictions. The possible mechanism is the nonlinear distortion effect caused by high-energy laser pumping.Our study is very important and useful for developing intense terahertz systems with applications in extreme terahertz sciences and nonlinear phenomena.
BAOLONG ZHANGSHANGQING LISHUSU CHAIXIAOJUN WuJINGLONG MALIMING CHENYUTONG LI
