Lin Deng

Reconfigurable Electro-optic Logic Circuits Using Microring Resonator-Based Optical Switch Array

In this paper, we propose a reconfigurable electro-optic logic circuit, which can perform any combinatorial logic operations using a microring resonator (MRR)-based optical switching array. The operands are represented by electrical signals, which are applied to the corresponding MRRs to control their switching status. The operation results are directed to the output port in the form of light. For proof of concept, the circuit consisting of four thermooptic MRR-based optical switches is fabricated on the silicon-on-insulator (SOI) substrate using the commercial complementary metal-oxide-semiconductor (CMOS) fabrication process. Finally, several logic operations of four operands with the operation speed of 10 kb/s are demonstrated successfully.

All-optical tunable microfiber knot resonator with graphene-assisted sandwich structure

We demonstrate an all-optical tunable microfiber knot resonator (MFKR) by direct light-graphene interaction using external vertical incidence pump laser. The 1530 nm CW pump source is employed to irradiate the sample, which can achieve the performance modulation of MFKR including transmission loss, extinction ratio, and resonant wavelength by the saturable absorption, photo-thermal, and optical Kerr effects, respectively. Compared with the MFKR with only the bottom graphene film, the tunable ranges of transmission loss and extinction ratio are increased by 69 and 125 times, respectively, which can induce a remarkable amplitude tuning. The resonant wavelength of MFKR occurs a red-shift under the irradiation of the pump light, and the red-shift range can exceed one free spectral range (FSR), which means the resonant wavelength could be tuned in the full wavelength range of the transparent window of optical fiber. It is promising for the device to be applied as an all-optical modulator, tunable optical filter, etc.

Optical mode switch based on multimode interference couplers

In this paper, we propose an optical mode switch based on two cascaded multimode interference (MMI) couplers. After a fundamental mode divided into two equal-power fundamental modes in the first MMI coupler, the thermo-optic effect is employed to modulate the phase of the two fundamental modes before directed to the next MMI for the purpose of mode switching. By adjusting the electric signals applied to the modulation arms, the proposed device can implement mode switching in three states: (a) one first-order and two fundamental modes simultaneously output, (b) one first-order mode output, and (c) two fundamental modes output. As a result, the simulated excess losses are −0.29 dB, −0.10 dB, and −0.63 dB, respectively.

Experimental realization of an optical digital comparator using silicon microring resonators

Abstract We propose and experimentally demonstrate a silicon photonic circuit that can perform the comparison operation of two-bit digital signals based on microring resonators (MRRs). Two binary electrical signals regarded as two operands of desired comparison digital signals are applied to three MRRs to modulate their resonances through the microheaters fabricated on the top of MRRs, respectively (here, one binary electrical signal is applied to two MRRs by a 1×2 electrical power splitter, which means that the two MRRs are modulated by the same binary electrical signal). The comparison results of two binary electrical signals can be obtained at two output ports in the form of light. The proposed device is fabricated on a silicon-on-insulator substrate using the complementary metal-oxide-semiconductor fabrication process, and the dynamic characterization of the device with the operation speed of 10 kbps is demonstrated successfully.

Experimental demonstration of an optical Feynman gate for reversible logic operation using silicon micro-ring resonators

Abstract Currently, the reversible logic circuit is a popular research topic in the field of information processing as it is a most effective approach to minimize power consumption, which can achieve the one-to-one mapping function to identify the input signals from its corresponding output signals. In this letter, we propose and experimentally demonstrate an optical Feynman gate for reversible logic operation using silicon micro-ring resonators (MRRs). Two electrical input signals (logic operands) are applied across the micro-heaters above MRRs to determine the switching states of MRRs, and the reversible logic operation results are directed to the output ports in the form of light, respectively. For proof of concept, the thermo-optic modulation scheme is used to achieve MRR’s optical switching function. At last, a Feynman gate for reversible logic operation with the speed of 10 kbps is demonstrated successfully.

Tunable optical filter using second-order micro-ring resonator

In this paper, we design and fabricate a silicon integrated optical filter consisting of two cascaded micro-ring resonators and two straight waveguides. Two micro-heaters are fabricated on the top of two micro-rings respectively, which are employed to modulate the micro-rings to perform the function of a tunable optical filter by the thermo-optic effect. The static response test indicates that the extinction ratio and 3-dB bandwidth are 29.01 dB and 0.21 nm respectively, the dynamic response test indicates that the 10%-90% rise and 90%-10% fall time of the filter are 16 mu s and 12 mu s, respectively, which can meet the requirements of optical communication and information processing. Finally, the power consumption of the device is also characterized, and the total power consumption is about 9.43 mW/nm, which has been improved efficiently.