Research On Key Techniques In Ultra-large Capacity Multiple Wavelength All-optical Regeneration And In OEO Based High-precision Absolute Distance Measurements Over A Long Range

In this thesis, the research work are carried out mainly on the key technologies in twofields including ultra-large-capacity all optical multiple wavelength regeneration andhigh-precision absolute distance measurements over a long range based on twooptoelectronic oscillators.In order to meet the increasing requirements on the current network transmissionrequirements, large-capacity transmission technology has become a hotspot of currentresearch. The corresponding all-optical regeneration is one of the key technologiesthat must be addressed. A study of large capacity multi-wavelength regeneration wascarried out in our research.Systems: We have experimentally demonstrated capacity of160Gb/s (4×40Gb/s)and320Gb/s (2×160Gb/s) all-optical3R regeneration. Based on the results above,simultaneous all-optical2R regeneration of capacity of640Gb/s WDM-PDM signalsis achieved. This is the largest capacity all optical regeneration for multiple channelswhich has been reported.Technology: The SBS can be suppressed by using degraded data signals as thepump in a FWM process. At the same time amplitude noise on both “0” and “1” levelscan be suppressed simultaneously very well, which is confirmed by bathtub curves.Bidirectional propagation in the fiber and polarization multiplexing are used to relievethe inter-channel interference among the four channels. A0.5bit slot time delaybetween the two co-propagating signals introduced by an optical delay line (ODL) canmitigate the inter-channel interference.Theoretical methods: A new evaluation method of3R regeneration system isproposed. Using this method, the performance of regeneration systems can be showedcomprehensively. This new method will provide a basis of how to set regenerationsystems in network.The measurement technique is the foundation of all science and technology.High-precision absolute distance measurement over a long range (from severalhundred meters to kilometers) is always a major technical challenge, which is studiedin this thesis based on the formerly achieved results of photonic microwave.Systems research: The maximum error is1.5μm at the emulated~6km distance,including the drift error of about1μm in the air path due to the change in environmental conditions. The highest relative measurement precision of2.5×10-10can be achieved in our current system. This is the highest relative accuracy which hasbeen achieved on such a large range.Technology: Traditional method tried to improve instrument resolution in orderto make the accuracy of the measurement better. Our scheme takes advantage ofaccumulative magnification theory, which makes the precision of the measureddistance significantly improved under the premise of the same accuracy of theinstrument. This method reduces the requirement on the device and enhances thetolerance of all interference.Principle: The principle of distance measurement based on OEO is proposed thefirst time. Utilizing the OEO’s characteristic of long cavity, high spectral purity andhigh resonant frequency, the change of distance is magnified105~106times in anOEO system. In this way, measurement accuracy of the record can be achieved usingordinary equipment.Technology: By using two OEOs, self-referencing can be achieved. One OEOserves as stabilization of the cavity length. The other is utilized to measure distance.The common optical path of the two OEOs is stabilized though a phase-locked loop(PLL) and the PZT, which can make sure of the accuracy of the measurement.There are some results in this thesis on both all-optical multi-wavelengthregeneration and absolute distance measurement, which are a good foundation forfurther research work.