Two types of silicon dual-ring resonator-based high-speed optical modulators are proposed. With two microring resonators cascaded either in series or in parallel, the transmission spectrum evolves from a deep notch to a sharp peak with the resonators operating in a push-pull manner. The frequency chirp of the modulated signals can be highly suppressed by choosing a proper working wavelength.

We experimentally demonstrate silicon variable optical attenuators (VOAs) based on thermally tunable Mach–Zehnder interferometers (MZIs). Thermo-optic tuning is enabled by a silicon resistive micro-heater positioned beside the MZI arm. Experimental results reveal that the maximum attenuation is around 30dB with 50mW power consumption. Compared with the p–i–n diode based VOA, the MZI-VOA is more power efficient and compact. The influence of MZI arm length on the performance of MZI-VOA is also investigated. The maximum attenuation voltage for the MZI-VOA with a 50μm long arm length is around 6.6V.

We numerically investigate an ultrafast all-optical switching device with an integrated silicon microring and a Mach-Zehnder (MZ) coupler. The device exhibits pico-second switching speed with only 0.09π of phase shift achieved by cross-phase modulation (XPM).

We investigate the photocurrent generation with surface-state absorption effect in a silicon waveguide integrated with periodically interleaved p-n junctions. Due to the high electric field (~5 × 10 5 V/cm) and large depletion area coverage in the waveguide, our device can collect more photocurrent than regular p-i-n and p-n structures. The responsivity of our device is optical power dependent with a higher value at a lower power level. The measured 3-dB bandwidth of the frequency response is 11.5 GHz. Although its responsivity is low compared to that of III-V and Ge photodiodes, its simple fabrication and compatibility with all-silicon photonic devices makes it suitable as on-chip optical power monitors.

We propose a miniature optical intensity modulator based on a silicon-polymer-metal hybrid plasmonic waveguide. Benefiting from the high mode confinement of hybrid plasmonic waveguide and the high linear electro-optic effect of polymer material, the intensity modulator is ultra-compact with a length of only ~ 13 μm. The device is optimized using numerical simulations based on the finite element method (FEM). The modulator exhibits a large modulation bandwidth of 90 GHz, a modulation depth of 12 dB at 6 V, and low power consumption of 24.3 fJ/bit.

We investigate the influence of coupling strength on self-coupled optical waveguide (SCOW) resonators. Experimental results reveal that the SCOW resonator transmission spectrum can exhibit single-channel or dual-channel stopbands with the band splitting level determined by the two coupling coefficients. Electrically tunable SCOW resonators comprising 2×2 Mach-Zehnder interferometer couplers are also demonstrated, which shows a similar change trend upon coupling tuning.

We investigate the photocurrent generation in a silicon waveguide embedded with interleaved p-n junctions. Due to the surface-state absorption and the high built-in electrical-field, the responsivity reaches ~14.9 mA/W and the bandwidth is 11.5 GHz.

We present a reflective-type delay line using side-coupled integrated spaced sequence of resonators (SCISSOR) terminated with a Sagnac loop reflector. With 13 microrings, group delay of ~150 ps is achieved with 170 GHz bandwidth.

We present a CMOS-compatible temperature-independent tunable silicon lattice filter composed of 10 cascaded 2×2 asymmetric Mach-Zehnder interferometers. Experiments show the device has a wide wavelength tuning range and low temperature sensitivity of ~6.2 pm/°C.

We present our recent work on integrated silicon photonic devices for optical filter and delay applications. A microdisk resonator integrated with interleaved p-n junctions is demonstrated. The resonance can be both blue- and red-shifted by applying a forward current or a negative voltage, respectively. A MZI-nested microring resonator is shown capable of coupling tuning, enabled by a p-i-p junction based thermal heater across the waveguide. We also investigate cascaded self-coupled optical waveguide (SCOW) resonators. Electromagnetically-induced transparency (EIT)-like resonances are generated featuring a narrow lineshape and a high group delay. Finally, we present an athermal lattice filter made up of 10 cascaded Mach-Zehnder interferometer (MZI) units and show that the temperature sensitivity can be considerably reduced.

We experimentally demonstrate two-stage self-coupled optical waveguide (SCOW) resonators. Coupled-resonator-induced-transparency (CRIT) and high-order filtering features are observed. Resonance spectrum is tunable via a p-i-p thermal resistor or a p-i-n diode.

We experimentally demonstrate tunable silicon comb filters based on Fabry-Perot resonators composed of Sagnac loop mirrors using periodically-interleaved PN junctions. Forward and reverse biases blue- and red-shift the comb lines, respectively.

We present a CMOS-compatible athermal tunable silicon optical lattice filter composed of 10 cascaded 2 × 2 asymmetric Mach-Zehnder interferometers. Active tuning experiments show that the filter central wavelength can be red-/blue-shifted by 13.1/21.3 nm with power consumption of 77/96 mW on top/bottom arms. Temperature shift measurements show that the thermal-sensitivity of the filter central wavelength before active tuning is as low as -1.465 pm/°C. The thermal-sensitivity is varied within 26.5 pm/°C to -27.1 pm/°C when the filter central wavelength is tuned in the wavelength range of 1534 nm to 1551 nm. We use the transfer matrix method to theoretically model the lattice filter and its thermal-sensitivity before and after tuning is analyzed and discussed.

We report a microring optical filter using Vernier effect. Tuning is enabled by a p-i-p resistor-based micro-heater integrated inside the resonators. Experiments show the filter wavelength can be tuned by 47 nm.

We present a method to selectively excite resonances in microring resonators by using a pulley-coupling structure. Experimental results reveal only certain resonances are excited, due to the dispersions of coupling-coefficient and microring internal-loss.

We investigate two-photon absorption (TPA) induced photocurrent generation in a microdisk resonator embedded with interleaved p-n junctions. Due to the strong electric field across the p-n junctions, free-carrier recombination rate is considerably reduced leading to an increased photocurrent.

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text L. Lu, L. Zhou, X. Sun, J. Xie, Z. Zou, X. Li, and J. Chen, "Athermal Silicon Mach-Zehnder Lattice Filters," in International Photonics and Optoelectronics Meetings, OSA Technical Digest (online) (Optica Publishing Group, 2012), paper ITh4A.08. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

We present our recent work on silicon resonance and slow-light based devices for optical signal processing. Waveguide self-coupling and mutual coupling are used to tailor the waveguide spectral and dispersion characteristics. With selfcoupling, optical resonances are generated with unique transmission performances. Electromagnetically induced transparency (EIT)-like effect appears in cascaded self-coupled waveguides. With mutual coupling between ridge and slot waveguides, group velocity experiences a big jump and optical signal can be delayed for a large range with low distortion by using thermo-optic tuning.

We experimentally demonstrate a self-coupled optical waveguide (SCOW)-based optical resonator. Transmission spectra reveal the resonators can exhibit split, broadened, or enhanced resonance dips. The SCOW resonators can be used for second-order optical filters.

Novel highly-efficient power combiners based on evanescently-coupled micro/nano optical fibers are proposed and experimentally demonstrated. Experimental results show that the maximum power combing efficiency can be >90%. The combining efficiency is overlap length dependent. As long as the overlap length is long enough (∼7mm), a stable high combining efficiency can always be achieved. The presented optical power combiners with the advantages of easy fabrication, low-loss, low-cost, and wavelength insensitivity can find potential applications in micro/nano photonic devices, optical communications and optical interconnects.