Laser array with the scale of 1 ×16 for optical vector-matrix multiplier as long as its driven circuit was designed and implemented. A 1 ×16 laser array was constructed by coupling 16 commercial discrete distributed feedback (DFB) lasers with a 1×16 fiber array. Calibrating module adopting feedback algorithm was equipped with the laser array driven circuit, successfully solving problems encountered due to differences of threshold current and P-I conversion efficiency among lasers of the same type. And the same mapping relationship was acquired between the input vector and output intensity power among different channels of the source array. The proposed light source array system together with its driven circuit not only reduces cost, but also possesses excellent high-frequency response,ensuring the stability and accuracy of the optical vector matrix multiplier′s computing performance.
We report on an eight-channel reconfigurable optical add-drop multiplexer based on cascaded microring resonators with a high tuning power consumption and a compact footprint. Microheaters are fabricated on top of the microring resonators and can be modulated using the thermo-optic effect to achieve the reconfigurable functionality of the device. We demonstrate the reconfigurable add-drop multiplexing functionality for channel spacings of 100 GHz and 50 GHz, with the centre wavelengths of the channels aligned to International Telecommunication Union grid specifications. The crosstalk for channel spacings of 100 GHz and 50 GHz are less than 22: 5 dB and 15: 5 dB, respectively. The average tuning efficiency is about 4.5 mW/nm, and the response speed is about 13.0 kHz.
Optical computing is a new method to implement signal processing functions. The multiplication between a vector and a matrix is an important arithmetic algorithm in the signal processing domain. The optical vector-matrix multiplier (OVMM) is an optoelectronic system to carry out this operation, which consists of an electronic module and an optical module. In this paper, we propose an optical module for OVMM. To eliminate the cross talk and make full use of the optical elements, an elaborately designed structure that involves spherical lenses and cylindrical lenses is utilized in this optical system. The optical design software package ZEMAX is used to optimize the parameters and simulate the whole system. Finally, experimental data is obtained through experiments to evaluate the overall performance of the system. The results of both simulation and experiment indicate that the system constructed can implement the multiplication between a matrix with dimensions of 16 by 16 and a vector with a dimension of 16 successfully. (C) 2013 Optical Society of America
A new system of generalized mixed implicit equilibrium problems is introduced and studied in real reflexive Banach space. A system of generalized equation problems is considered and its equivalence with the system of generalized mixed implicit equilibrium problems is shown. The iterative algorithm of the solutions is constructed and analyzed through a fixed point formulation of the generalized equation problems. The existence of solutions for the equilibrium problems is obtained. The convergence of the iterative sequences generated by the algorithm is proved under suitable conditions. The results in this paper extend and improve some known results in the literature.
We demonstrate a 26 Gbit/s Mach-Zehnder silicon optical modulator. The doping concentration and profile are optimized, and a modulation efficiency with the figure of merit (VπL) of 1.28 V·cm is achieved. We design an 80-nm-wide intrinsic silicon gap between the p-type and n-type doped regions to reduce the capacitance of the diode and prevent the diode from working in a slow diffusion mode. Therefore, the modulator can be driven with a small differential voltage of 0.5 V with no bias. Without the elimination of the dissipated power of the series resistors and the reflected power of the electrical signal, the maximum power consumption is 3.8 mW.
We demonstrate a five-port optical router for photonic networks-on-chip. The proposed topology design improves the performances in terms of power consumption, optical loss, crosstalk and channel uniformity of the optical router.
We fabricate a directed optical logic circuit on silicon-on-insulator platform which can implement the addition of two bits. For proof of concept, a thermo-optic switch effect is employed with an operation speed of 10kbps.
We demonstrate a five-port optical router for photonic networks-on-chip. The proposed topology design improves the performances in terms of power consumption, optical loss, crosstalk and channel uniformity of the optical router.
We demonstrate a carrier-depletion optical modulator with the driving voltage swing of 2 V and the extinction ratio of 12.79 dB at 12.5 Gbit/s. Even the driving voltage is reduced to 1 V, the the device still has an extinction ratio of 7.67 dB.
A universal method to constructing scalable non-blocking optical router for photonic NoC is proposed, which has fewer microring resonators, fewer waveguides and fewer crossings.
We report the implementation of the XOR and XNOR operations using an electro-optic directed logic circuit based on two cascaded silicon microring resonators (MRRs), which are both modulated through the plasma dispersion effect. PIN diodes are embedded around the MRRs to achieve the carrier-injection modulation. The inherent resonance wavelength mismatch between the two nominally identical MRRs caused by fabrication errors is compensated by two local microheaters above each MRR through the thermo-optic effect. Two electrical modulating signals applied to the MRRs represent the two operands of the two operations. Simultaneous bitwise XOR and XNOR operations at 100 Mbit/s are demonstrated.
A directed logic circuit consisting of two silicon microring resonators which can perform XOR and XNOR operations has been proposed. These two operations are evaluated as the optical signal is directed along the circuit, and the results appear at some specific output ports of the circuit. A potential advantage of this new logical paradigm is that it has markedly less state delay than traditional logic circuits. Devices based on the above proposal are fabricated on an 8-inch silicon-on-insulator wafer. The microring resonators in the circuit are modulated through thermo-optic effect. Two electrical modulating signals applied to the microring resonators represent the two operands of the logical operation respectively. Bitwise XOR and XNOR operations at 20 kbit/s are demonstrated. The scattering matrix method is adopted to analyse the transmission spectra of the circuit. The symmetrical characteristics of the spectra are well described by this model. The potential applications of this device are given.
We propose and demonstrate a directed OR/NOR and AND/NAND logic circuit consisting of two parallel microring resonators (MRRs). We use two electrical signals representing the two operands of the logical operation to modulate the two MRRs through the thermo-optic effect, respectively. The final operation results are represented by the output optical signals. Both OR/NOR and AND/NAND operations at 10 kbps are demonstrated.
As a result of the low modulation efficiency of carrier-depletion Mach-Zehnder silicon optical modulator, it always needs a high voltage around 6 V, which is very difficult to supply in an integrated high-speed CMOS chip. We demonstrate a carrier-depletion Mach-Zehnder silicon optical modulator which works at a low voltage. Its coplanar waveguide electrode is carefully designed to make sure the electrical wave loss along the device is low. The device operates well at a data rate of 12.5 Gb/s, whose phase-shifter length is 2 mm. Voltages with the swinging amplitudes being 1 V and 2 V are applied to the device with the reverse bias voltages of 0.5 V and 0.8 V. The extinction ratios are 7.67 and 12.79 dB respectively.
We design and fabricate a four-port optical router, which is composed of eight microring-resonator-based switching elements, four optical waveguides and six waveguide crossings. The extinction ratio is about 13 dB for the through port and larger than 30 dB for the drop port. The crosstalk of the measured optical links is less than -13 dB. The average tuning power consumption is about 10.37 mW and the tuning efficiency is 5.398 mW/nm. The routing functionality and optical signal integrity are verified by transmitting a 12.5 Gb/s PRBS optical signal.
Highly luminescent near-infrared (NIR) emitting CdTe/CdSe quantum dots (QDs) were prepared through a fast and convenient method, and a new type of multivalent polymer ligands was used as the surface substituents to prepare highly stable hydrophilic QDs with small sizes. The well-defined CdTe/CdSe QDs were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and photoluminescence (PL) spectroscopy, respectively. The as-prepared CdTe/CdSe QDs were photostable with high PL quantum yields (QYs) (up to 66% at room temperature), low toxicity to cells at experimental dosages, and the QDs' fluorescence emissions were tunable between 700 and 820 nm. Furthermore, fluorescence imaging using CdTe/CdSe QDs conjugated with the AS1411 aptamer (targeting nucleolin) probe in cancer cells was reported, and the CdTe/CdSe QDs were also successfully applied for the fluorescence imaging of living animals. Our preliminary results illustrated that the CdTe/CdSe NIR-QDs with small sizes would be an alternative probe for ultrasensitive, multicolor, and multiplex applications, especially for in vivo imaging applications.
Multi-objective optimization and vector variational-like inequality are two important topics in applied mathematics, and an interesting topic is to study their relationships under the generalized convexity conditions. This paper deals with the relationships between multi-objective optimization problems and variational-like inequalities under the semi-strong E-convexity assumptions and the relationships between the (weakly)efficient solutions and vector critical points for multi-objective optimization problems and the the solutions of (weak) vector variational-like inequalities are established.
We experimentally demonstrated four- and five-port non-blocking optical routers for photonic networks-on-chip. The optical routers are based on cascaded microring resonators. New topology design reduces the number of microring resonators and crossings, improving the performances in terms of tuning power consumption, optical loss, crosstalk and channel uniformity of the optical routers. The efficient footprints are 300×340 μm2 and 440×660 μm2 for fourand five-port optical routers, respectively. Static spectrum tests show that the 3-dB bandwidths are larger than 0.12 nm and 0.31 nm, the extinction ratios are larger than 13 dB and 20 dB for through ports, 30 dB and 16 dB for drop ports, for four- and five-port optical routers, respectively. Moreover, routing functionality and signal integrity are verified by 12.5 Gbps high-speed signal transmission experiments using the NRZ 231-1 PRBS pattern.
We experimentally demonstrate a spatially non-blocking five-port optical router, which is based on microring resonators tuned through the thermo-optic effect. The characteristics of the microring-resonator-based switching element are investigated to achieve balanced performances in its two output ports. The optical router is fabricated on the SOI platform using standard CMOS processing. The effective footprint of the device is about 440×660 μm2. The microring resonators have 3-dB bandwidths of larger than 0.31 nm (38 GHz), and extinction ratios of better than 21 dB for through ports and 16 dB for drop ports. Finally, 12.5 Gbps high-speed signal transmission experiments verify the routing functionality of the optical router.