A novel scheme for generating optical chaos is proposed and experimentally demonstrated,which supports to simultaneously produce two low-correlation chaotic signals with wideband spectrum and suppressed time-delay-sig...A novel scheme for generating optical chaos is proposed and experimentally demonstrated,which supports to simultaneously produce two low-correlation chaotic signals with wideband spectrum and suppressed time-delay-signature(TDS).In the proposed scheme,we use the output of an external-cavity semiconductor laser(ECSL)as the driving signal of a phase modulator to modulate the output of a CW laser.Then the phase-modulated continuous-wave(CW)light is split into two parts,one is injected back into the ECSL that outputs one chaotic signal,while the other part is passed through a dispersion module for generating another chaotic signal simultaneously.The experimental results prove that the proposed scheme has three merits.Firstly,it can improve the bandwidth of ECSL-based chaos by several times,and simultaneously generate another wideband flat-spectrum chaotic signal.Secondly,the undesired TDS characteristics of the simultaneously-generated chaotic signals can be efficiently suppressed to an indistinguishable level within a wide parameter range,as such the complexities of the chaotic signals are considerably high.Thirdly,the correlation coefficient between these two simultaneously-generated chaotic signals is smaller than 0.1.The proposed scheme provides an attractive solution for parallel multiple chaos generation,and shows great potential for multiple channel chaos communications and multiple random bit generations.展开更多
We present a novel precise angle measurement scheme based on parallel multiplex laser feedback interferometry （PLFI）, which outputs two parallel laser beams and thus their displacement difference reflects the angle ...We present a novel precise angle measurement scheme based on parallel multiplex laser feedback interferometry （PLFI）, which outputs two parallel laser beams and thus their displacement difference reflects the angle variation of the target. Due to its ultrahigh sensitivity to the feedback light, PLFI realizes the direct non-contact measurement of non- cooperative targets. Experimental results show that PLFI has an accuracy of 8＂ within a range of 1400＂. The yaw of a guide is also measured and the experimental results agree with those of the dual-frequency laser interferometer Agilent 5529A.展开更多
Based on a semiconductor laser （SL） with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs （MFCs） is proposed and investigated numerically. The ...Based on a semiconductor laser （SL） with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs （MFCs） is proposed and investigated numerically. The results show that, under suitable operation parameters, the SL with incoherent optical feedback can be driven to operate at a regular pulsing state, and the generated MFCs have bandwidths broader than 40 GHz within a 10 dB amplitude variation. For a fixed bias current, the line spacing （or repetition frequency） of the MFCs can be easily tuned by varying the feedback delay time and the feedback strength, and the tuning range of the line spacing increases with the increase in the bias current. The linewidth of the MFCs is sensitive to the variation of the feedback delay time and the feedback strength, and a linewidth of tens of KHz can be achieved through finely adjusting the feedback delay time and the feedback strength. In addition, mappings of amplitude variation, repetition frequency, and linewidth of MFCs in the parameter space of the feedback delay time and the feedback strength are presented.展开更多
We propose a method for optimizing the phase stability of microwave signal transmission over long distances.First,the design of the photon link was modified to reduce the radio frequency(RF)signal’s baseline noise an...We propose a method for optimizing the phase stability of microwave signal transmission over long distances.First,the design of the photon link was modified to reduce the radio frequency(RF)signal’s baseline noise and increase power.Second,a low-noise driver circuit was developed for a two-section distributed feedback(DFB)laser designed using reconstruction equivalent chirp(REC)technology to create an ultra-stable laser,and its performance was characterized through linewidth data.Test results indicate that the DFB laser achieved narrower linewidth,improving system phase stability.When an injection current(30 mA)is applied to the reflection section of the two-section DFB laser,the laser linewidth will be narrower(1.38 MHz),further enhancing the system’s phase transmission stability.At a 1 Hz offset frequency,a residual phase noise of-88.65 dBc/Hz is obtained.The short-term stability with an averaging time of 1 s is 1.60×10^(-14),and the long-term stability over a testing time of 60,000 s is 3.41×10^(-18).Even after incorporating temperature variations,the long-term stability reaches 8.37×10^(-18) at 22 h.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant no.62171087,61671119)the Sichuan Science and Technology Program(Grant no.2021JDJQ0023)the Fundamental Research Funds for the Central Universities(Grant no.ZYGX2019J003).
文摘A novel scheme for generating optical chaos is proposed and experimentally demonstrated,which supports to simultaneously produce two low-correlation chaotic signals with wideband spectrum and suppressed time-delay-signature(TDS).In the proposed scheme,we use the output of an external-cavity semiconductor laser(ECSL)as the driving signal of a phase modulator to modulate the output of a CW laser.Then the phase-modulated continuous-wave(CW)light is split into two parts,one is injected back into the ECSL that outputs one chaotic signal,while the other part is passed through a dispersion module for generating another chaotic signal simultaneously.The experimental results prove that the proposed scheme has three merits.Firstly,it can improve the bandwidth of ECSL-based chaos by several times,and simultaneously generate another wideband flat-spectrum chaotic signal.Secondly,the undesired TDS characteristics of the simultaneously-generated chaotic signals can be efficiently suppressed to an indistinguishable level within a wide parameter range,as such the complexities of the chaotic signals are considerably high.Thirdly,the correlation coefficient between these two simultaneously-generated chaotic signals is smaller than 0.1.The proposed scheme provides an attractive solution for parallel multiple chaos generation,and shows great potential for multiple channel chaos communications and multiple random bit generations.
基金supported by the National Natural Science Foundation of China(Grant No.61036016)
文摘We present a novel precise angle measurement scheme based on parallel multiplex laser feedback interferometry （PLFI）, which outputs two parallel laser beams and thus their displacement difference reflects the angle variation of the target. Due to its ultrahigh sensitivity to the feedback light, PLFI realizes the direct non-contact measurement of non- cooperative targets. Experimental results show that PLFI has an accuracy of 8＂ within a range of 1400＂. The yaw of a guide is also measured and the experimental results agree with those of the dual-frequency laser interferometer Agilent 5529A.
基金supported by the National Natural Science Foundation of China(Grant Nos.61178011,11204248,61475127,and 61275116)the Natural Science Foundation of Chongqing City,China(Grant Nos.2012jj B40011 and 2012jj A40012)the Open Fund of the State Key Lab of Millimeter Waves of China(Grant No.K201418)
文摘Based on a semiconductor laser （SL） with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs （MFCs） is proposed and investigated numerically. The results show that, under suitable operation parameters, the SL with incoherent optical feedback can be driven to operate at a regular pulsing state, and the generated MFCs have bandwidths broader than 40 GHz within a 10 dB amplitude variation. For a fixed bias current, the line spacing （or repetition frequency） of the MFCs can be easily tuned by varying the feedback delay time and the feedback strength, and the tuning range of the line spacing increases with the increase in the bias current. The linewidth of the MFCs is sensitive to the variation of the feedback delay time and the feedback strength, and a linewidth of tens of KHz can be achieved through finely adjusting the feedback delay time and the feedback strength. In addition, mappings of amplitude variation, repetition frequency, and linewidth of MFCs in the parameter space of the feedback delay time and the feedback strength are presented.
基金This work was supported by the National Key R&D Program of China(No.2020YFB2205804)the National Natural Science Foundation of China(Nos.62273355,62374092,61975075,61975076,and 62004094).
文摘We propose a method for optimizing the phase stability of microwave signal transmission over long distances.First,the design of the photon link was modified to reduce the radio frequency(RF)signal’s baseline noise and increase power.Second,a low-noise driver circuit was developed for a two-section distributed feedback(DFB)laser designed using reconstruction equivalent chirp(REC)technology to create an ultra-stable laser,and its performance was characterized through linewidth data.Test results indicate that the DFB laser achieved narrower linewidth,improving system phase stability.When an injection current(30 mA)is applied to the reflection section of the two-section DFB laser,the laser linewidth will be narrower(1.38 MHz),further enhancing the system’s phase transmission stability.At a 1 Hz offset frequency,a residual phase noise of-88.65 dBc/Hz is obtained.The short-term stability with an averaging time of 1 s is 1.60×10^(-14),and the long-term stability over a testing time of 60,000 s is 3.41×10^(-18).Even after incorporating temperature variations,the long-term stability reaches 8.37×10^(-18) at 22 h.
