CN1858643A - Raman amplifying method for optical signal in surface plasma wave nano optical wave guide - Google Patents

Abstract

This invention relates to a method for amplifying optical signals in a surface plasma nm optical waveguide, which utilizes a specific pump light to pump a nano-optical waveguide device having a determined working wavelength based on the Raman effect and the pump light and the signal light are held in a same optical waveguide, in which, the Raman pump optical source wavelength is selected based on the working wavelength of the device and its optical power is decided based on the signal optical power and the structure of the device to enlarge the application sphere of nano-optical waveguide based on plasma waves.

Description

The Raman amplification method of light signal in the surface plasma-wave nano optical wave guide

Technical field

The invention belongs to the integrated optics technique field, particularly the amplification method of light signal in a kind of surface plasma-wave nano optical wave guide.

Background technology

Along with progress of science and technology and industrialized development, optical device miniaturization day by day, integrated.Yet because the influence of diffraction limit, the traditional sucrose optical waveguide has its weakness in essence in the constraint to light, light effectively can not be limited in the scope of lateral dimension much smaller than wavelength.This just forces the researchist to seek can retrain the effective way of light to the sub-wavelength scope.And can realize constraint to the photon nanoscale based on the nano optical wave guide device of surface plasma-wave, thereby promoted the realization of minute sized various optical device (optical chip), and brought the revolutionary development of integrated optics as optic communication device, optical sensor device etc.

Compare with other traditional waveguides based on the nano optical wave guide of surface plasma-wave and to have remarkable advantages, promptly can be tied to littler yardstick to light, realize littler waveguide device.When yet this nano optical wave guide is applied to light transmission, have serious defective, promptly optical loss is very big, has limited its application.And successfully being applied to optical fiber telecommunications system based on the light signal amplification technology of Ramam effect, the light signal that the experience that it accumulated is embodied as nano optical wave guide amplifies based theoretical.

Summary of the invention

The present invention proposes light signal in a kind of surface plasma-wave nano optical wave guide based on the Ramam effect amplifying method, the loss with compensation waveguide itself has solved nano optical wave guide light signal loss problem.

Method of the present invention adopts the amplification method based on Ramam effect, to a nano optical wave guide device that definite operation wavelength is arranged, with specific pump light nano optical wave guide device is carried out pumping exactly, and pump light and flashlight constrain in the same optical waveguide.Because the Ramam effect of nano optical wave guide device material, flashlight wherein is exaggerated, and has compensated the loss of flashlight.Pumping light wavelength and the power method of determining nano optical wave guide device are:

1, according to the operation wavelength λ of nano optical wave guide device ₁, selected raman pump light source wavelength X ₂, both wavelength satisfy formula (1),

${\mathrm{\λ}}_2=c/(\frac{c}{{\mathrm{\λ}}_1}+v)---\left(1\right)$

Wherein c is a vacuum light speed, and v is the optical phonon frequency of nano optical wave guide material, is the Raman frequency shift amount of nano optical wave guide material.

2, determine the power of pump light according to nano optical wave guide device signal light power and structure, with the loss of compensating signal light.

For under the flashlight of same direction transmission and pump light satisfy, establishing an equation in the bar shaped nano optical wave guide device:

$\left\{\begin{array}{c}\frac{{\mathrm{dI}}_s}{\mathrm{dz}}=g{I}_p{I}_s-{\mathrm{\α}}_s{I}_s\\ \frac{{\mathrm{dI}}_p}{\mathrm{dz}}=-\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_p}{\mathrm{gI}}_p{I}_s-{\mathrm{\α}}_p{I}_p\end{array}\right.---\left(2\right)$

For in the bar shaped nano optical wave guide device in opposite direction the flashlight of transmission and pump light establish an equation under satisfying:

$\left\{\begin{array}{c}\frac{{\mathrm{dI}}_s}{\mathrm{dz}}={\mathrm{gI}}_p{I}_s-{\mathrm{\α}}_s{I}_s\\ \frac{{\mathrm{dI}}_p}{\mathrm{dz}}=\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_p}{\mathrm{gI}}_p{I}_s+{\mathrm{\α}}_p{I}_p\end{array}\right.---\left(3\right)$

Wherein, g is the Raman gain coefficienct of nano optical wave guide material, I _pBe pumping light power, I _sBe signal light power, α _sBe the attenuation coefficient of the flashlight of nano optical wave guide material, α _pAttenuation coefficient for pump light.Wherein g, α _s, α _pDetermine by nano optical wave guide device material and structure, at known signal power I _sSituation under, can calculate pumping light power I by formula (2) _p

Nano optical wave guide device for other structure, by analysis to its structure, the nano optical wave guide of complexity is split into the combination of a plurality of bar shaped nano optical wave guides, equation that satisfies according to flashlight and pump light in each bar shaped nano optical wave guide and the boundary condition between each bar shaped nano optical wave guide can be determined the power of pump light equally.This kind combination calculation is a mature technology.

The present invention mainly is applicable to designs and the application at integrated optics technique field light nano optical wave guide surface plasma-wave.Because the Ramam effect of nano optical wave guide makes flashlight because the amplification of Ramam effect has been offset the intrinsic loss of nano optical wave guide device, has expanded the range of application based on the plasma wave nano optical wave guide.This method has convenience of calculation, simple operation and other advantages.

Description of drawings

Fig. 1 is one embodiment of the invention one-piece construction synoptic diagram.

Embodiment

As shown in Figure 1, this nano optical wave guide device is etching waveguide 3 in silicon dioxide substrate 1, and waveguide 3 both sides plating silver form a bar shaped nano optical wave guide device in silicon dioxide substrate 1.The relative dimensions parameter is: d1=10.05 μ m, d2=5 μ m, d3=0.05 μ m, d4=0.05 μ m, d5=5 μ m, d6=1 μ m.

This device operation wavelength is λ ₁=1550nm, the optical signal power that incides in the nano optical wave guide is 0.1mW.At first Theoretical Calculation is as follows: the Raman frequency shift amount by the determined nano optical wave guide device material of Fig. 1 (silicon dioxide) is v=13.2 * 10 ¹²Hz according to formula (1), calculates the pump light wavelength X ₂=1451nm.According to material (silicon dioxide and silver) characteristic and operation wavelength, it is as follows that we obtain correlation parameter: the attenuation coefficient α of flashlight _s=4.5822 * 10 ^{+ 4}m ^-1, the attenuation coefficient α of pump light _p=4.8637 * 10 ^{+ 4}m ^-1, Raman gain coefficienct g=13.36W ^-1m ^-1According to formula (2), in order to make flashlight constant through the power after the nano metal waveguide, i.e. I _s(0)=I _s(d6), the pumping light power that calculates the waveguide of incident nano metal is I _p=168W.In actual use,, select the pump light of corresponding wavelength for use, set pump light source power, pump light is injected nano optical wave guide device, realize the Raman of flashlight in the nano optical wave guide is amplified according to calculated value according to incoming signal power degree.

Claims (2)

1, the Raman amplification method of light signal in the surface plasma-wave nano optical wave guide, it is characterized in that this method adopts the amplification method based on Ramam effect, exactly to a nano optical wave guide device that definite operation wavelength is arranged, with specific pump light nano optical wave guide device is carried out pumping, pump light and flashlight constrain in the same optical waveguide;

Operation wavelength λ according to nano optical wave guide device ₁, selected raman pump light source wavelength X ₂, both wavelength satisfy formula (1),

${\mathrm{\λ}}_2=c/(\frac{c}{{\mathrm{\λ}}_1}+v)---\left(1\right)$

Wherein c is a vacuum light speed, and v is the optical phonon frequency of nano optical wave guide material, is the Raman frequency shift amount of nano optical wave guide material;

Determine the power of pump light according to nano optical wave guide device signal light power and structure.

2, the Raman amplification method of light signal in the surface plasma-wave nano optical wave guide as claimed in claim 1 is characterized in that satisfying equation (2) for flashlight and the pump light along same direction transmission in the bar shaped nano optical wave guide device in the described power of determining pump light according to nano optical wave guide device signal light power and structure:

$\left\{\begin{array}{c}\frac{{\mathrm{dI}}_s}{\mathrm{dz}}=g{I}_p{I}_s-{\mathrm{\α}}_s{I}_s\\ \frac{{\mathrm{dI}}_p}{\mathrm{dz}}=-\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_p}g{I}_p{I}_s-{\mathrm{\α}}_p{I}_p\end{array}\right.---\left(2\right)$

Satisfy equation (3) for the flashlight and the pump light that transmit in opposite direction in the bar shaped nano optical wave guide device:

$\left\{\begin{array}{c}\frac{{\mathrm{dI}}_s}{\mathrm{dz}}=g{I}_p{I}_s-{\mathrm{\α}}_s{I}_s\\ \frac{{\mathrm{dI}}_p}{\mathrm{dz}}=-\frac{{\mathrm{\λ}}_s}{{\mathrm{\λ}}_p}g{I}_p{I}_s-{\mathrm{\α}}_p{I}_p\end{array}\right.---\left(3\right)$

Wherein g is Raman gain coefficienct, the I of nano optical wave guide material _pBe pumping light power, I _sBe signal light power, α _sAttenuation coefficient, α for the flashlight of nano optical wave guide material _pAttenuation coefficient for pump light.