非线性光学晶体电光快速调谐光参量器件的研制

Optical parametric lasers widely using in many science and technology field owin g to its merit of wide tunable spectrum range.But common optical parametric lase rs achieve tune by change of angel or temperature.The tune velocity and tune pre cision of these tune modes does not satisfy in many applications.The reporting i nto an optical parametric laser which achieve tune by electooptic effect,that have got speediness tune velocity and relatively quite tune precision. The optical parametric device design based on parametric fluorescent produce thr ough sum frequency phase matching in nonlinear optical crystals.It is a tune pr o cess of refractive index about parametric and pump light in nonlinear optical cr ystals namely.But refractive index of nonlinear optical crystals possess electro o ptic effect can change via apply transformable electro field.This change only w a nts a time of ns grade.So optical parametric device with nonlinear optical cryst als possess suitability electrooptic effect can realize speediness tune in princ iple.The idea about design on the recommended device here is somewhat as follows .The tune model is phase tuning.To strive increase the effect of electro optic f unction under keep immovable polarization directions of 3 wavelength in the opti cal parametric process,to strive convenient for apply electro field,the electro field is only sensitive for a refractive index of some wavelength in specificall y spectrum region.The principium examination has showed that the idea is reasona ble.Our count have show also that its tune precision same as expectance.

A cost-effective 100-Gb/s transmitter with low-speed optoelectronic devices and high spectral efficiency

A 100-Gb/s high-speed optical transmitter is proposed and experimentally demonstrated. Based on frequency-quadrupling technique, two sub-channels with a fixed 50-GHz spacing are obtained from one laser source. Using return-to-zero differential quadrature phase-shift keying （RZ-DQPSK） modulation format and polarization multiplexing （PolMux）, only low-speed electronic devices of 12.5 GHz are needed for the 100-Gb/s transmitter. This eliminates the need of ultrahigh-speed optoelectronic devices and thus greatly reduces the cost. The experimental results show that this transmitter can achieve good performance in dispersion tolerance of a 25-km single mode fiber （SMF）.

Optical coherent detection Brillouin distributed optical fiber sensor based on orthogonal polarization diversity reception

In Brillouin distributed optical fiber sensor, using optical coherent detection to detect Brillouin scattering optical signal is a good method, but there exists the polarization correlated detection problem. A novel detecting scheme is presented and demonstrated experimentally, which adopts orthogonal polarization diversity reception to resolve the polarization correlated detection problem. A laser is used as pump and reference light sources, a microwave electric-optical modulator (EOM) is adopted to produce frequency shift reference light, a polarization controller is used to control the polarization of the reference light which is changed into two orthogonal polarization for two adjacent acquisition periods. The Brillouin scattering light is coherently detected with the reference light, and the Brillouin scattering optical signal is taken out based on Brillouin frequency shift. After electronic processing, better Brillouin distributed sensing signal is obtained. A 25-km Brillouin distributed optical fi

LD-pumped high repetition rate Q-switched Nd:YVO_4 laser by using La_3Ga_5SiO_(14) single crystal electro-optic modulator

A diode-end-pumped electro-optic （EO） Q-switched Nd：YVO4 laser operating at repetition rate of 10 kpps （pulses per second） was reported. A block of La3Ga5SiO14 （LGS） single crystal was used as a Q-switch and the driver was a metal oxide semiconductor field effect transistor （MOS-FET） pulser of high repetition rate and high voltage. At continuous wave （CW） operation, the slope efficiency of the laser was 46%, and maximum optical-to-optical efficiency was 38.5%. Using an output coupler with transmission of 70%, a 10-kpps Q-switched pulse train with 0.4-mJ monopulse energy and 8.2-ns pulse width was achieved, the optical conversion efficiency was around 15%, and the beam quality M^2 factor was less than 1.2.

Analysis of electro-optic switches with series-coupled multiple microring resonators

In terms of the coupled mode theory, microring resonance and electro-optic modulation princeple, a reasonable project is proposed for designing an electro-optic switch with the series-coupled multiple microring resonators. The simulation and optimization are performed at the resonant wavelength of 1550 nm. The results are as follows: the core size of the microring is 1.6 μm×1.6 μm, the confined layer between the core and the electrode is 1.6 μm, the thickness of the electrode is 0.15 μm, the radius of the m...

Silicon electro-optic modulator with high-permittivity gate dielectric layer

A high-permittivity （high-k） material is applied as the gate dielectric layer in a silicon metal-oxide- semiconductor （MOS） capacitor to form a special electro-optic （EO） modulator. Both induced charge density and modulation efficiency in the proposed modulator are improved due to the special structure design and the application of the high-k material. The device has an ultra-compact dimension of 691 μm in length.

Single-side-band optical modulation in SCM systems for high-speed optical transmission

In order to decrease dispersion penalty and increase the optical bandwidth efficiency,an optical single-side-band modulation(SSBM) scheme in sub-carrier multiplexing(SCM) is proposed.The principle of the SSBM is analytically presented,and a configuration for generating optical SSB signal is proposed using a balanced Mach-Zehnder electro-optic modulator.

Laser pulse spectral shaping based on electro-optic modulation

A new spectrum shaping method, based on electro-optic modulation, to alleviate gain narrowing in chirped pulse amplification （CPA） system, is described and numerically simulated. Near-Fourier transform-limited seed laser pulse is chirped linearly through optical stretcher. Then the chirped laser pulse is coupled into integrated waveguide electro-optic modulator driven by an aperture-coupled-stripline （ACSL） electricalwaveform generator, and the pulse shape and amplitude are shaped in time domain. Because of the direct relationship between frequency interval and time interval of the linearly chirped pulse, the laser pulse spectrum is shaped correspondingly. Spectrum-shaping examples are modeled numerically to determine the spectral resolution of this technique. The phase error introduced in this method is also discussed.

Study on electro-optic properties of two-dimensional PLZT photonic crystal band structure

The band characteristics of two-dimensional(2D) lead lanthanum zirconate titanate(PLZT) photonic crystals are analyzed by finite element method.The electro-optic effect of PLZT can cause the refractive index change when it is imposed by the applied electric field,and the band structure of 2D photonic crystals based on PLZT varies accordingly.The effect of the applied electric field on the structural characteristics of the first and second band gaps in 2D PLZT photonic crystals is analyzed in detail.And the results show that for each band gap,the variations of start wavelength,cut-off wavelength and bandwidth are proportional to quadratic of the electric field.