Influence of degenerate four-wave mixing on the performance of supercontinuum-based multiwavelength optical source

The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation results show that the degenerate FWM effect has a deteriorative influence on the spectral uniformity and the optical signal-to-noise ratio （OSNR） of supercontinuum-based optical source, and by suppressing degenerate FWM effect the performance enhancement of the supercontinuum can be achieved successfully. These results are also confirmed by our experiments. Experimentally, by suppressing degenerate FWM the crosstalk of adjacent channels to the filtered channel can be reduced by as much as 15 dB, and consequently the measured receiver sensitivity at 10 Gbit/s for the filtered optical source is improved from -1.7 to -17.8 dBm.

Nearly Degenerate Four-Wave Mixing in Semiconductor-doped Glasses

This paper presents the nearly degenerate four wave mixing properties of glass doped with semiconductor CdS x Se 1-x ,nonlinear response time of the material obtained by the laser induced transient grating technique,and properties of photoluminescence of the glass and the blue shift in the luminescence spectra with an increasing intensity of input beam as well. The nonlinearity of the material is believed to be due to the band filling in semiconductor microcrystallites.

Higher-order squeezing of quantum field and higher-order uncertainty relations in non-degenerate four-wave mixing

It is found that the field of the combined mode of the probe wave and the phase conjugate wave in the process of non-degenerate four-wave mixing exhibits higher-order squeezing to all even orders. The higher-order squeezed parameter and squeezed limit due to the modulation frequency are investigated. The smaller the modulation frequency is, the stronger the degree of higher-order squeezing becomes. Furthermore, the hlgher-order uncertainty relations in the process of non-degenerate four-wave mixing are presented for the first time. The product of higher-order noise moments is related to even order number N and the length L of the medium.

A NEW METHOD FOR IMAGE TRANSMISSION USING FOUR-WAVE MIXING

A new method using degenerate four-wave mixing for one-way imaging through phase distorting medium is presented.The theoretical analysis and experimental results are given.

Measurement of the carrier recovery time in SOA based on four-wave mixing on narrow-band ASE spectrum

Carrier recovery time is a key parameter that determines the performance of a semiconductor optical amplifier （SOA）. A measurement method of carrier recovery time in SOA based on a nearly degenerate four-wave mixing of narrowband amplified spontaneous emission （ASE） spectra is presented. The results show the carrier times are 50.2, 44.6, and 23.6 ps when the injected currents are 120, 180, and 240 mA, respectively, which are in agreement with the nominal values of the sample.

各向同性介质的三阶非线性极化统一理论

探讨了入射至各向同性介质的不同频率的多光束;推导了三阶非线性极化矢量形式的表达式,并利用它解释了多个已知且独立的非线性光学现象,验证了该表达式的普适性和正确性.结果表明,三阶非线性极化矢量形式的表达式可为各向同性介质中的三阶非线性光学效应提供统一描述;将其拓展至六角晶系材料,能对各种复杂问题提供简单的处理方式.这对于系统地理解各向同性介质和六角晶系材料中的三阶非线性光学效应具有重要意义,有望促进非线性光学在频率转换、偏振态检测和量子信息等领域中的应用.

Q-factor improvement of degenerate four-wave-mixing regenerators for ASE degraded signals

All-optical regenerators can be used to suppress amplified spontaneous emission(ASE) noise introduced by cascaded erbium doped fiber amplifiers(EDFAs) in optical fiber communication systems and lead to the improvement of optical receiver sensitivity. By introducing the Q-factor transfer function(QTF), we evaluate the Q-factor performance of degenerate four-wave mixing(DFWM) regenerators with clock pump and reveal the differences between the optimal input powers determined from the static and dynamic power tranfer function(PTF) and the QTF curves. Our simulation shows that the clock-pump regnerator is capable of improving the Q-facor and receiver sensitivity for 40 Gbit/s ASE-degraded return-to-zero on-off keying(RZ-OOK) signal by 2.58 dB and 4.2 d B, respectively.

DEGENERATE FOUR-WAVE MIXING FOR EXCITING STATES OF MOLECULES

Ⅰ. INTRODUCTION By using degenerate four-wave mixing (DFWM) method, the third-order nonlinear optical susceptibility of transparent media can be conventionally measured. Nonlinear properties of media in ground state are well known, but those in exciting state are less studied. When a medium absorbs incident radiation, a part of population can be excited into high exciting state. In DFWM this resonant enhancement effect can be used to increase the third-

BACKWARD-WAVE PARAMETRIC OSCILLATION BY DEGENERATE FOUR-WAVE MIXING

Ⅰ. INTRODUCTIONIn ordinary degenerate four-wave mixing experiments, parametric amplification is generated, i.e., when an object wave with a certain intensity is incident on a nonlinear medium, backward reflective wave of the very object wave would be

吡啶酮偶氮化合物三阶非线性光学性质的研究

根据三维简并四波混频耦合理论，推导了前向位相共轭光的场强方程．用三维简并四波混频实验测定了１４种吡啶酮偶氮化合物溶液的三阶非线性极化率χ（３），并计算了分子的三阶非线性超极化率γ．结果表明，推拉型吡啶酮偶氮化合物具有较强的三阶非线性光学性能．

聚芳香杂环甲烯的三阶非线性光学效应与时间分辨光克尔效应(英文)

合成了一系列聚芳香杂环甲烯 ,包括聚吡咯甲烯和聚噻吩甲烯。采用四波混频法研究材料的共振三阶非线性光学效应 (λ =5 32nm) ,其共振二阶超分子极化率γ三阶非线性光学系数分别达到 10 - 3 0 esu和10 - 8esu 选择具有良好溶解性、成膜性的聚吡咯对二甲氨基苯甲烯 (PPDMAB) ,采用飞秒时间分辨光克尔效应方法研究材料的非共振三阶非线性光学效应 (λ =790nm) 实验表明 ,翠绿亚胺碱溶液的光克尔信号仅表现一超快响应的成分 ,归功于π电子云扭转产生的非共振激发 PPDMAB的非共振二阶超分子极化率γ三阶非线性光学系数分别达到γ =5 .78× 10 - 3 2 esu和 χ(3 ) =1.2 6× 10 - 10

偶氮苯聚合物5-NO_2-PADAT及其与Pd(Ⅱ)的螯合物光存储特性

本文制备了偶氮苯聚合物５－ＮＯ２－ＰＡＤＡＴ和它与Ｐｄ（Ⅱ）形成的螯合物，用简并四波混频的方法测量了它们的三阶非线性系数及光存储特性，通过对测量结果的分析。

可溶性聚(2-甲氧基-5-辛氧基)对苯乙炔的合成及其导电和三阶非线性光学性能

通过双醚化反应、氯甲基化反应和在强碱性条件下进行的脱氯化氢反应 ,制备出可溶性聚 (2 甲氧基 5 辛氧基 )对苯乙炔 (PMOCOPV)。利用红外光谱 (IR)、紫外 可见吸收光谱 (UV Vis)、核磁共振谱 (1HNMR)和凝胶渗透色谱 (GPC)对产物PMOCOPV的结构进行了表征。将I2 、Br2 、FeCl3 和H2 SO4作为掺杂剂 ,对PMOCOPV进行掺杂反应 ,得到了电导率分别为 4 7 2、2 1 6、32 5和 2 7S/cm的掺杂态PMOCOPV。采用简并四波混频 (DFWM )方法研究了PMOCOPV的三阶非线性光学性质。研究发现 ,PMOCOPV具有大的三阶非线性光学效应 ,在 5 32nm下的共振三阶非线性极化率和 10 6 4nm下的非共振三阶非线性极化率 χ(3 ) 分别为 6 8× 10 -10 esu和 1 2× 10 -11esu。

3种偶氮化合物的合成及三阶非线性光学性能

合成了3种1,3,4-噻二唑偶氮化合物,其中1种为新化合物,用IR、~1H NMR和元素分析表征了其结构。采用飞秒激光,运用简并四波混频法,研究了化合物在非共振状态下的三阶非线性光学性能。它们的三阶非线性光学极化率x^(3)为(3.84～3.95)×10^(-13)esu,非线性折射率n_2为(7.07～7.27)×10^(-12)esu,分子二阶超极化率γ为(3.56～3.72)×10^(-31)esu,响应时间τ为101fs。探索了化合物的分子结构对三阶非线性光学性能的影响。引入离域能小的芳杂环,形成吸供构型,增大取代基的吸或供电子能力等有利于获得较大的三阶非线性光学性能。

方酸衍生物的三阶非线性光学特性

采用波长为800nm、脉宽为50fs的激光系统，运用双光束前向简并四波混频技术（DFWM）研究了两种方酸衍生物的三阶非线性光学特性，并探讨了它们的非线性形成机制。实验测得所研究的两种方酸衍生物的分子超极化率7值均为～10^-31esu，其非线性光学响应时间小于激光脉宽（50fs）。因而，所研究的方酸衍生物有较大的三阶非线性光学性质和较快的光学响应，在光学器件中具有潜在的应用价值。

蒽二酮类化合物的合成及结构-非线性光学性能关系的研究

设计合成了6个新的蒽二酮类化合物,用紫外可见吸收光谱、傅里叶变换红外光谱、1H核磁共振和元素分析表征了结构.采用飞秒激光,运用简并四波混频法,研究了化合物在非共振状态下的三阶非线性光学性能.它们的三阶非线性光学极化率χ(3)为2.62～3.55×10-13esu,非线性折射率n2为4.82～6.52×10-12esu,分子二阶超极化率γ为2.57～3.25×10-31esu,响应时间τ为91～116fs.探索了化合物的分子结构对三阶非线性光学性能的影响.增长共轭链,形成供吸供构型,增大取代基的供电子能力,提高共轭体系的共平面程度等因素有利于获得较大的三阶非线性光学性能.

外加气体对碘的简并四波混频的影响

研究了入射激光能量密度,外加气体(N_2,CO_2,NO_2)对碘的简并四波混频(DFWM)光谱和信号强度的影响,测定了I_2的DFWM信号的饱和强度与外加气体压强之间的关系.结果表明外加气体对I_2的DFWM光谱结构的影响不大,但对信号强度的影响较大,而且与激光能量密度有关.I_2的DFWM信号的饱和强度(I_(sat))与N_2压强(p)之间的关系为I_(sat)∝p^(0.7).当激光能量密度足够大时,外加气体对信号的增强作用是热光栅所产生的.

PAZOS的合成及其薄膜的光信息存储研究

合成并表征了聚[3’-甲基-4’-二（N，N-氧亚乙基）氨基-4-硝基偶氮苯癸二酰]（PAZOS），利用简并四波混频（DFWM）方法在聚合物薄膜中实现了光信息存储．光致异构引起的偶氮苯生色团的重取向是光信息存储的机制．通过研究写入顺序，发现在光信息存储过程中，写入光是前向泵浦光和探测光，读出光是后向泵浦光，信息的写入-擦除过程是可逆的．

非相干光时延四波混频中V型三能级原子的布居弛豫量子拍的理论研究

对简并非相干光时延四波混频中布居弛豫量子拍的物理机制及产生过程进行了理论研究 ,并根据真空与原子耦合观点 ,具体分析讨论了两种情形的三宽带光脉冲作用于 V型三能级原子布居弛豫量子拍的形成过程和讯号特征 .经比较发现 。

有机功能色素类化合物的合成与三阶非线性光学性能

设计并合成了苯并二呋喃酮、双偶氮-9,10-蒽二酮、苯并噻蒽以及偶氮-1,3,4-噻二唑4个系列的有机色素类化合物,并用UV,IR,^1H NMR和元素分析表征了结构.采用飞秒激光,运用简并四波混频法,研究了化合物的三阶非线性光学性能.它们的三阶非线性光学极化率χ^（3）为2.64～3.95×10^-13esu,非线性折射n2为4.85～7.27×10^-12esu,分子二阶超极化率γ为2.85～3.72×10^-31esu.探索了化合物的分子结构对三阶非线性光学性能的影响.长的共轭链、吸供取代基和杂环的引入、取代基强的供电子或吸电子能力等因素有利于获得较大的三阶非线性光学性能.