| With respect to the different application occasions,the traditional ranging technologies have been rapidly developed,such as ultrasonic ranging,infrared ranging,electromagnetic ranging,laser ranging and so on.Yet the ranging precision derived from these traditional ranging technologies is always constrained in Standard Quantum Limit(SQL)or Shot Noise Limit(SNL).Differently,quantum ranging technology is capable to beat SQL or SNL and to force into Heisenberg Limit(HL)through the peculiar quantum properties such as entanglement and squeezing.Especially,the scheme of quantum precision ranging based on the Hong-Ou-Mandel(HOM)interferometer could provide a precision of 100 fs(subpicosecond level)for detecting the minimum time-interval,i.e.the ranging precision reaches to the micrometer magnitude.It authentically brings a new thought for the research on the neotype navigation and positioning system in the future and has the important application significance.This thesis deeply explores the ranging principle of the HOM interferometer that structures a one-to-one correspondence(“HOM effect”)between the zero time-delays and the zero value in the coincidence counts(“Mandel Dip”).And then we present some generalized HOM interferometer configurations for achieving the high-dimensional extension of “HOM effect” through the means of expanding the “Mandel Dip” from the form with a single time-delay parameter to that with multiple time-delay parameters.Therefore,the numerical estimation problem with respect to multiple independent time-delay parameters is solved and the length differences of multiple pairs of optical paths are obtained thereby achieving the quantum ranging.Besides,the application scenarios are proposed from two aspects,quantum positioning and quantum communication,by virtue of the characterizations of the generalized HOM interferometer with the high ranging accuracy and the superior security.The relevant works as following: 1.The traditional HOM interferometer only employs the frequency entangled light as input without considering the classical light,in response to this research background we present the comparative analysis on the ranging performance of the HOM interferometer which,bases on the quantum light source and the classical light source respectively.We found that the “HOM effect” could be realized by whatever using the biphoton state or the coherent state as the input in the ideal channel after analyzing the results of the coincidence counts associated with these two states.However,the zero value in the coincidence counts caused by the coherent state accompanies with a series of fast parameter oscillations.These parameter oscillations directly affect the visibility of the coincidence dip,which indicates that the quantum light source is a better choice than the classical light source.Besides,the results of the coincidence counts based on these two quantum states are contrastively analyzed in the lossy channel,which is used to state the effects of photon losses on the ranging performance of the HOM interferometer.2.To beat the constraint of that only one time-delay parameter could be recovered from the traditional HOM interferometer,we present a HOM interferometer scheme with two timedelay parameters.This scheme employs another 50:50 beam splitter(BS)and a quarter of wave plate compared with the traditional HOM interferometer.In the ideal case,the input biphoton state allows realizing the two-dimensional extension of the “HOM effect” thereby fulfilling the quantum ranging,which means that the two independent time-delay parameters could be recovered by identifying the “Mandel Dip” associated with two time-delay parameters.However in the presence of fluctuating parameters,the unique zero value of the coincidence counts is unfortunately washed away,but the values of two time-delay parameters could still be estimated from the symmetric characteristics of the coincidence counting results.Besides,the superiority of the quantum light source as the input for high precision ranging is clarified by contrastively analyzing the coincidence counts derived from the biphoton state and the coherent state in the ideal channel and the lossy channel,respectively.3.As for the numerical estimation problem with respect to multiple independent time-delay parameters,we present a HOM interferometer scheme with three time-delay parameters that introduces an extra 50:50 BS compared to the counterpart scheme with two time-delay parameters,and a quarter of wave plate still remains.There is no a unique correspondence between the zero value of the coincidence counts based on the biphton state and the case that all of these three time-delay are zero through traversing the different time-delay cases.In other words,it is failed to achieve the three-dimensional extension of the “HOM effect” by means of the “Mandel Dip” with three time-delay parameters.However,in the presence of fluctuating parameters,these three time-delay parameters could still be recovered in two steps from the symmetric characteristics in the results of the coincidence counts.4.In view of the application prospects of the above two types of the generalized HOM interferometer schemes,taking the quantum positioning system(QPS)as an example,we propose the new theoretical models of the quantum positioning system based on these two types of the generalized HOM interferometers.Especially deducing the solution process of the spatial three-dimensional coordinates of the target user in a simplified QPS model based on a generalized HOM interferometer with two time delays.Compared with the conventional QPS,the variant QPS only requires two the generalized HOM interferometers that each one associates with two time delays,to solve the four-dimensional coordinates of the target user.Besides,a generalized HOM interferometer with three time delays is enough to solve the spatial three-dimensional coordinates of the target user,which optimizes the hardware resource in the QPS.5.In allusion to the drawback that the arrival time of a single photon has a low precision in the protocol of BB84 quantum key distribution with the vacuum decoy state,we present an optimization QKD scheme combined with the method of quantum precision ranging.Specifically,replacing the time of arrival(TOA)of a single photon with the average TOA of M frequency-entangled photons,which provides the lower quantum bit error rate and the higher key rate.In addition,considering that the full entanglement scheme is sensitive to the photon losses,a partial entanglement scheme and a grouping entanglement scheme are respectively proposed.Especially,the grouping entanglement scheme is capable of promoting the resistance of the QKD system face to the photon losses at the cost of discarding a part of TOA precision.Besides,a strategy for choosing an optimal scheme among these three schemes in the lossy channel is discussed.The simulation results show that no matter which one is selected as the optimal scheme,it would bring a better QKD performance than the traditional single-photon scheme does. |
PDF Full Text Request