We investigate the effects of refractive index encapsulant on light-extraction efficiency (LEE) light-emitting diodes (LEDs) for GaN LEDs (n ≈ 2.5) and AlGaInP 3.0). For non-absorbing rectangular parallelepiped LED chips, as increases, LEE first increases quasi-linearly, then sub-linearly, finally a saturation is reached. Furthermore, with dual-layer graded-refractive-index (GRIN) (n(encapsulant 1) = 1.57 n(encapsulant 2) 1.41) fabricated through two-step curing process. demonstrate that...

Optical frequency combs (OFCs) play a key role in variety of applications and have been implemented primarily using mode-locked lasers, Kerr resonators, electro-optic (EO) modulation. EO modulation-based OFC generation may not yield as many comb lines nor span broad bandwidth lasers or resonators; however, it offers high degree tunability central spacing. Integrated solutions are interest they significantly reduce device footprint enable large scale system integration. In this paper, we...

An effective method to enhance the light extraction for GaInN light-emitting diodes (LEDs) is reported. The employs TiO2 micro-pillars with tapered sidewalls, which are refractive-index-matched underlying GaN. fabricated by using reflowed photoresist as mask during CHF3-based dry etch, O2 added in order precisely control taper angle. LEDs patterned sidewalls show a 100% enhancement light-output power over planar reference LEDs. measured results good agreement ray-tracing simulations, showing...

Radio frequency (RF) spectrum analysis is an essential technique for monitoring signal quality in ultrahigh-speed optical transmission, broad bandwidth photonic RF arbitrary waveform generation, and characterization of high repetition rate pulse sources. Whereas the intrinsic electronics limits its use measurement high-speed signals, a approach based on ultrafast Kerr nonlinear effects can readily measure signals having beyond 1 THz. The majority fiber-based or integrated analyzers reported...

We review the recent work on developing integrated microwave photonic subsystems in silicon photonics for performing radio-frequency spectral analysis, generating waveforms, and filtering signals.

All-optical signal processing based on nonlinear optical effects allows for the realization of important functions in telecommunications including wavelength conversion, multiplexing/demultiplexing, Fourier transformation, and regeneration, amongst others, ultrafast time scales to support high data rate transmission. In integrated photonic subsystems, majority all-optical systems demonstrated date typically process only a single channel at or perform function, which imposes serious...

We present a cooler-less, free-running 1550 nm vertical cavity surface emitting laser (VCSEL) directly modulated at 10.7 Gb/s. also report on error-free transmission through 40 km of standard single-mode optical fiber, achieved without the use dispersion-mitigation or mid-span amplification. Inverse-dispersion fiber was utilized to realize dispersion-matched 99.7 access uplink supporting with 27 dB loss margin. These results indicate feasibility implementing cooler-less long-wavelength VCSEL...

In this study, an improved HMM based recognition model is proposed for online English and Korean handwritten characters. The pattern elements of the handwriting are sub character strokes ligatures. To deal with problem style variations, a modified Hierarchical Clustering approach introduced to partition different writing styles into several classes. For each letters primitive grapheme in characters, one that models temporal spatial variability constructed on class. Then HMMs graphemes...

The unrestricted control of the surface structure and refractive index would allow for new improved functionalities in optoelectronic devices. Specifically, micro-patterned graded-refractive-index (GRIN) coatings can enable emission pattern promote light extraction GaInN light-emitting diodes (LEDs). We design demonstrate that are patterned into arrays GRIN micro-pillars, each composed five dielectric layers (TiO2)x(SiO2)1−x with bottom layer (adjacent to semiconductor) having highest top...

We demonstrate photonic generation of chirped microwave pulses (CMPs) using an integrated distributed Fabry-Pérot cavity (DFPC) in silicon-on-insulator as a spectral shaper. The DPFC is based on pair spatially offset Bragg gratings and has response with varying free range. shaper used to filter broadband from mode-locked fiber laser, CMPs are obtained at the output photodetector following wavelength-to-time mapping process dispersive medium. generate central frequency up 20 GHz,...

Patterned graded-refractive-index (GRIN) coatings that offer the controllability of far-field emission pattern and polarization properties GaInN light-emitting diodes (LEDs) are investigated. Compared with a planar reference LED, light-output power an LED patterned GRIN (GRIN LED) is enhanced by about 69%. Furthermore, has bidirectional peaks at 45° off-surface-normal polarized light maximum ratio occurring same angle, i.e. intensity polarization-ratio coincide. The large results from strong...

We demonstrate broadband mode-selective wavelength conversion based on cross-phase modulation in a silicon multimode waveguide. obtain error-free operation for 10 Gb/s RZ-OOK signals with power penalty of < 1.5 dB over range ±10 nm.

We present a compact optical add-drop multiplexer in silicon-on-insulator based on combining mode selection with Bragg reflection. The channel has 3-dB bandwidth of 2 nm, an extinction ratio 30 dB, and interferometric crosstalk less than -42 dB. characterize the inter-channel performance using BER measurements for 10-Gb/s NRZ data obtain induced power penalties 3.5

In the identification process of SSI–DATA method, stabilization diagram is generally used to determine order system. However, in modal parameter spatial grid structure, there are few stable points that meet requirements, and stability axis not obvious. So, location point cannot be determined. Furthermore, QR decomposition Hankel matrix computationally inefficient difficult use for online when analyzing structure. solve above problems, this paper proposes a time-saving random subspace method...

Four-wave-mixing microscopy is widely researched in both biology and medicine. In this paper, we present a simplified near-degenerate four-wave-mixing (SNDFWM). An ultra-steep long-pass filter utilized to produce an edge on the spectrum of femtosecond pulse, super-sensitive (FWM) signal can be generated via short-pass filter. Compared with current state-of-the-art FWM microscopy, SNDFWM has advantages simpler experimental apparatus, lower cost, easier operation. We demonstrate that high...

Microwave photonic (MWP) systems exploit the advantages of photonics, especially with regards to ultrabroad bandwidth and adaptability, features that are significantly more challenging obtain in electronic domain. Thus, MWP can be used realize a number microwave signal processing functions including, amongst others, waveform generation radio-frequency spectrum analysis (RFSA). In this paper, we review recent results on fiber integrated approaches for simultaneous multiple chirped waveforms...

We demonstrate an integrated SPM-based 2R optical regenerator in SOI comprising a silicon nanowire and step-chirped sidewall Bragg grating.

The MPEG-7 standard defines a set of descriptors that extract low-level features such as color, texture and object shape from an image generate metadata represents the extracted information. In this paper we propose new retrieval technique for indexing based on scalable color descriptor. We use some specifications descriptor (SCD) implementation histograms. 1 l norm − matching in SCD. But our approach, distance measurement, achieve better result by using cosine similarity coefficient This...

We demonstrate on-chip frequency comb generation using cascaded electro-optic Mach-Zehnder modulators in silicon photonics. Our produces 9 lines with a spacing of 6.67 GHz and an amplitude variation <; 3 dB.

For most people, Apple’s introduction of backside-illuminated (BSI) CMOS image sensors (CIS) in their iPhone4 may have been the first time they became aware this technology. Compared with traditional front-illuminated CMOS, light a BSI CIS can strike photocathode directly without passing through wiring layer. Thus, photon absorption efficiency increases from 60% to 90%. As size decreases, performance improves. Now, are widely used digital cameras, smartphones, etc. However, placing active...

Based on the date of Chinese A-Share listed company from 2010-2012, Our research found that some special relationgships between characteristics board directors and internal control goal.