نتایج جستجو برای: optical modulation

تعداد نتایج: 407672  

2001
D. Z. Anderson V. Damiao D. Popovic Z. Popovic S. Romisch A. Sullivan

Suppression of an optical carrier from an RF modulated laser beam of wavelength 532 nm is performed using two-beam coupling in photorefractive barium titanate. A theoretical analysis reveals that perfect suppression can be achieved at a specific modulation strength, which depends on the gain and intensity ratio between the two beams. The experiments achieve a maximum of −72.9±2.4 dB carrier sup...

Journal: :Optics letters 2004
Vilson R Almeida Michal Lipson

We demonstrate, for the first time to our knowledge, optical bistability on a highly integrated silicon device, using a 5-microm-radius ring resonator. The strong light-confinement nature of the resonator induces nonlinear optical response with low pump power. We show that the optical bistability allows all-optical functionalities, such as switching and memory with microsecond time response and...

1999
R. T. Chen

We report on an optically activated phase modulator (OAM) and modulator array on GaAs-GaAlAs compound semiconductor rib waveguides. A rib waveguide device with an optical activation window of 5 pm in diameter was fabricated. Optical activation was produced by using a HeNe 632.8 nm wavelength as the free-carrier generator and a 1.3 pm laser as the signal carrier. A 33% modulation depth was obser...

2001
Jon S. Lawrence Deb M. Kane

The nonlinear dynamic behavior of a direct frequency-modulated diode laser with strong optical feedback is examined and compared to a laser diode subject to electro-optically modulated, strong optical feedback. Direct modulation is achieved by sinusoidal modulation of the diode laser injection current. Electro-optic modulation is achieved by applying a sinusoidal voltage to an intracavity phase...

2012
Kyle N. Crabtree James N. Hodges Brian M. Siller Adam J. Perry Joseph E. Kelly Paul A. Jenkins Benjamin J. McCall

The technique of velocity modulation spectroscopy has recently been combined with cavity enhancement and frequency modulation methods into a technique called noise-immune cavity-enhanced optical heterodyne velocity modulation spectroscopy (NICE-OHVMS). We have implemented NICE-OHVMS with a cw-optical parametric oscillator (OPO) tunable from 3.2 to 3.9 lm, and used it to record spectra of the R(...

2008
M. Beck M. M. de Lima P. V. Santos

We present a new concept for waveguide acousto-optical devices based on coupled Mach–Zehnder interferometers driven by acoustic waves. These acousto-optical multiple interference devices use the periodic refractive index modulation induced by the acoustic wave to realize functionalities such as ON/OFF switching for an arbitrary time interval, as well as for efficient light modulation at high ha...

Journal: :Nano letters 2009
Jennifer A Dionne Kenneth Diest Luke A Sweatlock Harry A Atwater

Realization of chip-based all-optical and optoelectronic computational networks will require ultracompact Si-compatible modulators, ideally comprising dimensions, materials, and functionality similar to electronic complementary metal-oxide-semiconductor (CMOS) components. Here we demonstrate such a modulator, based on field-effect modulation of plasmon waveguide modes in a MOS geometry. Near-in...

2013
James N. Hodges

The technique of velocity modulation spectroscopy has recently been combined with cavity enhancement and frequency modulation methods into a technique called noise-immune cavity-enhanced optical heterodyne velocity modulation spectroscopy (NICE-OHVMS). We have implemented NICE-OHVMS with a cw-optical parametric oscillator (OPO) tunable from 3.2 to 3.9 lm, and used it to record spectra of the R(...

Journal: :بینا 0
اعظم عسگری1 asgari shahid sadoughi university of medical sciences, yazd, iranیزد-دانشگاه علوم پزشکی شهید صدوقی یزد-دانشکده پزشکی- گروه فیزیک پزشکی کیخسرو کشاورزی keshavarzi iran university of medical sciences, tehran, iranدانشگاه علوم پزشکی تهران علی اصغر پرچ parach shahid sadoughi university of medical sciences, yazd, iranیزد-دانشگاه علوم پزشکی شهید صدوقی یزد-دانشکده پزشکی- گروه فیزیک پزشکی

purpose: to assess the optical effect of the technis-z9000 iol decentration by lio-brennan mathematic-optical eye model. methods: the phantom with real eye parameters (lio-brennas) was used for iol technis-z9000 modeling with zemax code. modulation transfer function (mtf) and mtf contrast that represent the ratio of the image data to total object data in optical system were used for analysis. r...

Journal: :Optics letters 2013
Cheng Wang Fédéric Grillot Vassilios I Kovanis Joshua D Bodyfelt Jacky Even

A rate equation analysis on the modulation response of an optical injection-locked quantum cascade laser is outlined. It is found that the bifurcation diagram exhibits both bistable and unstable locked regions. In addition, the stable locked regime widens as the linewidth enhancement factor increases. It is also shown that both positive and negative optical detunings as well as strong injection...

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