Research on nonlinear optics and lutra high-speed fiber-optic transmission based on the theory of integrable systems

1.色散管理孤子的理论分析(A)我们发现，相邻色散管理(DM)孤子之间的初始幅度和/或相位差对减小脉冲间的相互作用是有效的。(B)我们在DM光纤中发现了对称的双孤子解，表现出极低的脉冲间相互作用。2.色散管理孤子的传输控制(A)通过在传输光纤中插入与传输孤子同步驱动的光学器件如带通滤光器和/或强度调制器来稳定DM孤子的能量。我们发现，这种效果强烈地依赖于器件的插入位置。此外，如果选择适当的强度调制器的位置，可以在没有光束通滤波器的情况下稳定脉冲能量。(B)通过逐位调整接收端的判决时间，我们发现信道间的相互作用可以大大降低信道间相互作用对WDM孤子传输的影响。…对于超高速(80Gbit/S)传输，我们提出了密集DM孤子，其色散管理周期比掺铒光纤放大器间隔短得多。3.超短光脉冲产生和孤子传输实验(A)提出了利用标准单模光纤和色散位移光纤构成的梳状色散轮廓光纤(CDPF)进行孤子传输。在10 Gbit/S、2,000 km的环路传输实验中，当EDFA间距为80 km时，误码率达到10~(-9)，是色散距离的两倍。(B)利用非RO色散位移光纤构建了60 km长的密集DM光纤，进行了40 Gbit/S密集DM孤子传输实验，观察到1630 km传输后的眼图。(C)1.6ps。利用CDPF和光脉冲压缩技术产生了160 GHz的光孤子脉冲。(D)在密集DM光纤中传输了两个间隔为10ps的3.7ps宽的光脉冲，观察到传输后脉冲间隔变短。2.6ps、87 GHz密集DM孤子的传输距离为600 km。4.非线性光学器件(A)分析了非对称色散结构的非线性光学环镜的开关特性。分析了主动锁模色散管理光纤环形激光器输出光脉冲的时间抖动和能量抖动。通过合理选择强度调制器和带通滤光器的位置，可以大大降低抖动。(C)提出了一种利用非线性光脉冲沿正常色散光纤传输的脉冲整形特性的新型光RZ接收机。实验结果表明，在10Gbit/S、12000公里光孤子传输中，光孤子的幅度和相位裕度都得到了很大的改善。较少

1.Theoretical analysis of dispersion managed solitons(a)We found that initial difference in amplitude and/or phase between neighboring dispersion managed(DM)soliton lses is effective to reduce the pulse-to-pulse interaction.(b)We discovered symmetric bi-soliton solution in DM fiber which showed extremely low pulse-to-pulse interaction.2.Transmission control of dispersion managed solitons(a)The energy of DM soliton is stabilized by inserting optical devices in transmission fiber such as optical bandpass filter and/or intensity modulator synchronously driven with the transmitting solitons. We found that the effectiveness strongly depended on the inserting position of the devices. Moreover, the pulse energy can be stabilized without optical bundpass filter if the position of the intensity modulator is properly chosen.(b)We found that the influence of channel-to-channel interaction on WDM soliton transmission can be greatly reduced by bit by bit tuning of the decision time of the receiver. … More (c)We proposed dense DM solitons where the period of the dispersion management is much shorter than the EDFA spacing for ultra-high speed(>80 Gbit/s)transmission. Dispersion slope compensation can be effectively done by inserting dispersion shifted fiber for the compensation right before EDFA's.3.Ultra short optical pulse generation and soliton transmission exeriment(a)We proposed the use of comb-like dispersion profiled fiber(CDPF)constructed by standard single mode fiber and dispersion shifted fiber for soliton transmission. The bit error rate of < 10-9 was achieved in 10 Gbit/s, 2,000 km transmission experiment in a recirculating loop, where the EDFA spacing of 80 km is twice as long as the dispersion distance.(b)We made 40 Gbit/s dense DM soliton transmission experiment with 60-km long dense DM fiber constructed by non-ro dispersion shifted fiber and observed eye pattern after 1,630 km transmission.(c)1.6ps. 160 GHz optical soliton pulses were generated by CDPF and optical pulse compression.(d)We transmitted two 3.7-ps width optical pulses with 10 ps separation in dense DM fiber and observed that the pulse separation became shorter after transmission. 2.6 ps, 87 GHz dense DM solitons were transmitted over 600 km.4.Nonlinear optical device(a)We analyzed the switching characteristics of nonlinear optical loop mirror(NOLM)where dispersion configuration of the loop is asymmetric. Both extinction ratio and switching threshold can be better than that of the conventional NOLM.(b)We analyzed timing and energy jitters included in the output optical pulses from actively mode-locked dispersion-managed fiber ring laser. Both jitters can be greatly reduced by properly choosing the position of the intensity modulator and the optical bandpass filter.(c)We proposed a new optical RZ receiver using pulse reshaping characteristics of nonlinear optical pulse propagating along normal dispersion fiber. We demonstrated that the amplitude and phase margins were greatly improved in 10 Gbit/s, 12,000 km optical soliton transmission. Less