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We have prepared a highly efficient non-doped green organic light-emitting diode (OLED) incorporating a novel 9,9-diarylfluorene-terminated 2,1,3-benzothiadiazole green emitter (DFBTA), which exhibits an excellent solid state photoluminescence quantum yield (81%), and new triaryldiamines (DPAInT2, DPAInF) with high hole mobility derived from rigid and coplanar cores. The optimal device: ITO/DPAInT2/DPAInF/TCTA/DFBTA/Alq3/LiF/Al displayed impressive device characteristics, including a maximum external quantum efficiency (h ext ) of 3.7% (12.9 cd A À1 ) and a maximum brightness at 168 000 cd m À2 .

The development of optical interconnect techniques greatly expands the communication bandwidth and decreases the power consumption at the same time. It provides a prospective solution for both intra-chip and inter-chip links. Herein reported is an integrated wavelength-division multiplexing (WDM)-compatible multimode optical switching system-on-chip (SoC) for large-capacity optical switching among processors. The interfaces for the input and output of the processor signals are electrical, and the on-chip data transmission and switching process are optical. It includes silicon-based microring optical modulator arrays, mode multiplexers/de-multiplexers, optical switches, microring wavelength de-multiplexers and germanium-silicon high-speed photodetectors. By introducing external multi-wavelength laser sources, the SoC achieved the function of on-chip WDM and mode-division multiplexing (MDM) hybrid-signal data transmission and switching on a standard silicon photonics platform. As a proof of concept, signals with a 25 Gbps data rate are implemented on each microring modulator of the fabricated SoC. We illustrated 25 × 3 × 2 Gbps on-chip data throughput with two-by-two multimode switching functionality through implementing three wavelength-channels and two mode-channel hybrid-multiplexed signals for each multimode transmission waveguide. The architecture of the SoC is flexible to scale, both for the number of supported processors and the data throughput. The demonstration paves the way to a large-capacity multimode optical switching SoC.

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We propose and experimentally demonstrate a five-port silicon optical switch based on the optimized Spanke-Beneš structure for 2-D-mesh network on chip. We optimize it by substituting optical waveguide crossings for 2 × 2 optical switching units. By this approach, the total number of optical switching units is reduced from 10 to 8 compared to a five-port optical switch based on Spanke-Beneš structure. The 2 × 2 optical switching unit is based on balanced Mach-Zehnder interferometers with integrated titanium nitride microheaters on both arms. The average operating power consumption of the whole switch is 215 or 178 mW for the left arm or right arm by using single-arm driving, which will be reduced to 89 mW by using dual-arm driving. The insertion losses (excluding coupling losses) of the five optical links under "all-cross" and "all-bar" states are 3.2-6.0 and 3.3-6.2 dB, respectively, in the wavelength range of 1525-1565 nm. The optical signal-to-noise ratios are larger than 12.2 dB in 1525-1565 nm. 40-Gb/s data transmission experiment is implemented to verify the transmission functionality. The 10-90% rising and 90-10% falling time of the optical switching units in the device by thermal tuning are all ∼17 μs.

Optical vortex (OV) laser is generated by the superposition of coherently phase-locked off-axis laser beamlets in a nearly semi-spherical optical resonator with intra-cavity azimuthal symmetry breaking (ASB) optics. Due to the ASB, this laser resonator rejects radiation to resonate on-axis but supports off-axis beamlets belonging to the multiple-pass transverse (MPT) modes. These independent off-axis MPT modes, which are experimentally proven to retrace V-shaped paths in the resonator span ring-shaped intensity distribution and are coherently phase-locked to form an OV with a wavefront dislocation mirroring the topological charge (TC) of the ASB optics. Pumped by a conventional diode laser without critical beam shaping, we successfully generate randomly polarized OV having an annular intensity distribution and a positive unit TC of more than 99.9% at a central wavelength of 1064 nm when the power of pump laser goes above 1.52 W. The build-up of the deterministic phase relation among the independent MPT modes is demonstrated by spatial coherence measurement of the laser from a perturbed ASB resonator. This ASB resonator not only provides an easy approach to generate intrinsic vortex laser with power scalability but also serves as an useful platform to shape laser beams structurally, to study the laser dynamics and to combine radiations coherently.