CN-121995390-A - Hybrid integrated non-correction linear frequency modulation DFB laser ranging system and ranging method thereof

Abstract

The invention discloses a hybrid integrated uncorrected linear frequency modulation (DFB) laser ranging system and a ranging method thereof, which relate to the technical field of laser radar ranging, and the hybrid integrated uncorrected linear frequency modulation (DFB) laser ranging system comprises a hybrid integrated packaging module, a first DFB laser, a second DFB laser, an optical circulator unit, a GPPO high-frequency radio frequency interface and an independent regulation and control unit, wherein the first DFB laser, the second DFB laser and the optical circulator unit are packaged in the hybrid integrated packaging module, the GPPO high-frequency radio frequency interface is arranged on the hybrid integrated packaging module, and the hybrid integrated uncorrected linear frequency modulation DFB laser ranging system and the ranging method thereof directly anchor the sweep linearity of a laser on a radio frequency source of an electric domain through a physical mechanism of sideband locking, thereby ensuring the sweep linearity of output optical frequency from the physical aspect, thoroughly omitting complex digital predistortion algorithm or expensive photoelectric phase-locked loop hardware, and greatly reducing the complexity of the system.

Inventors

• ZHANG YUNSHAN
• Zhou mengxi
• CHEN YIBING
• MA WENXUAN
• ZOU HUI
• XUE JIAWEN

Assignees

• 南京邮电大学

Dates

Publication Date

20260508

Application Date

20260303

Claims (5)

1. 1. A hybrid integrated non-correction linear frequency modulation DFB laser ranging system is characterized by comprising a hybrid integrated packaging module, a first DFB laser, a second DFB laser, an optical circulator unit, GPPO high-frequency radio frequency interfaces and an independent regulation and control unit, The first DFB laser, the second DFB laser and the optical circulator unit are packaged in the hybrid integrated packaging module, and the GPPO high-frequency radio frequency interface is arranged on the hybrid integrated packaging module; The optical circulator unit is positioned on the optical output paths of the first DFB laser and the second DFB laser, and the first DFB laser enters the second DFB laser after passing through the optical circulator unit to form sideband injection locking and then is output; the GPPO high-frequency radio frequency interface is connected with the first DFB laser and the second DFB laser and is used for injecting a linear frequency modulation signal to realize sideband locking; The independent regulation and control unit comprises a temperature control circuit and a current drive circuit which respectively and independently control the first DFB laser and the second DFB laser.
2. 2. The system of claim 1, wherein the first and second DFB lasers are integrally packaged on the same tube base, and are connected with the tube base pins on the tube base by wire bonding, and are respectively subjected to coarse temperature adjustment and fine current adjustment by independent adjusting units to set the central beat frequency 。
3. 3. The hybrid integrated correction-free chirped DFB laser ranging system as recited in claim 1 wherein the temperature control circuit and the current drive circuit are coupled to injection electrodes of the first DFB laser and the second DFB laser.
4. 4. The method for ranging a hybrid integrated uncorrected linear frequency modulation DFB laser ranging system as recited in claim 1, comprising the steps of: s1, respectively adjusting the temperature and injection current of the first DFB laser and the second DFB laser by an independent adjusting and controlling unit to ensure that the wavelength difference of the first DFB laser and the second DFB laser Corresponding to a preset central carrier frequency ; S2, injecting a linear frequency modulation microwave signal into a second DFB laser through a GPPO high-frequency radio frequency interface; s3, utilizing a sideband injection locking effect to lock the longitudinal mode frequency of the first DFB laser on a modulation sideband of a radio frequency signal; S4, after the first DFB laser and the second DFB laser beat frequency through the 3 port of the optical circulator unit, a Frequency Modulation Continuous Wave (FMCW) signal with high linearity is directly output, and an additional nonlinear correction algorithm is not needed.
5. 5. The method of claim 4, wherein the temperature control circuit and the current driving circuit are used to fine tune the current and the temperature control to reduce the center frequency requirement of the linear frequency modulation microwave signal, and the sideband injection locking mechanism is used to eliminate the nonlinear effect of the first DFB laser and the second DFB laser during the wide frequency sweep.

Description

Hybrid integrated non-correction linear frequency modulation DFB laser ranging system and ranging method thereof Technical Field The invention relates to the technical field of laser radar ranging, in particular to a hybrid integrated non-correction linear frequency modulation DFB laser ranging system and a ranging method thereof. Background The laser radar is used as a high-precision active detection technology and plays a key role in the fields of automatic driving, remote sensing mapping, wind speed measurement, environment monitoring and the like. Among them, frequency Modulation Continuous Wave (FMCW) lidar is the current research hotspot because of its advantages of high ranging accuracy, high sensitivity, no blind area detection capability, strong anti-interference, etc. The FMCW laser radar can simultaneously acquire the distance and speed information of the target through single measurement, and is suitable for miniaturization and integration development. However, the performance of FMCW lidars is highly dependent on the frequency modulation linearity of the light source. An ideal Chirp signal requires a linear change of frequency with time, but in practical application, a semiconductor laser (such as a DFB laser) is affected by factors such as a heating effect, a carrier concentration change, a driving circuit noise, an external environment disturbance and the like, and the output frequency of the signal is often nonlinear, so that the measurement accuracy and resolution of the system are seriously reduced. In order to solve the problem of nonlinearity of the light source, the prior art mainly adopts a nonlinear correction technology, and specifically includes: The predistortion technology is to construct a mapping relation between frequency and current based on an iterative algorithm, and to carry out predistortion treatment on a driving signal, wherein the algorithm is complex and sensitive to environmental change and has poor real-time performance although linearization to a certain extent can be realized; An opto-electric phase locked loop (OPLL) technique locks the scanning optical frequency to a highly stable reference frequency. The method has high precision, but the system hardware structure is complex, the cost is high, and the integration is difficult to realize; The resampling technology is to introduce an auxiliary interference light path to extract a clock signal, resample a measurement signal to eliminate nonlinearity, and the method increases the complexity of an optical system and the data volume of back-end signal processing; External modulation techniques, which utilize external modulators (e.g., SSB modulators, I/Q modulators) to generate the linear swept signal, introduce expensive and bulky external optics, which, although good in linearity, is detrimental to low cost and miniaturization of the system. In addition, when the conventional single-frequency FMCW laser radar works in an actual atmospheric environment, the conventional single-frequency FMCW laser radar is extremely susceptible to interference of atmospheric turbulence and speckle noise on the surface of a target, resulting in a decrease in signal-to-noise ratio of an echo signal, an increase in measurement error, and a double-frequency modulated continuous wave (DF-FMCW) laser radar has been proposed to solve this problem by emitting two laser beams having a specific frequency difference, which suppresses speckle and turbulence effects by utilizing the correlation of dual wavelengths. Therefore, there is a need for an integrated light source and ranging system that does not require complex nonlinear correction circuits or algorithms, has a simple structure, is resistant to environmental interference, and has high frequency modulation linearity characteristics, so as to meet the requirements of high precision, low cost, and real-time ranging and imaging. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a hybrid integrated non-correction linear frequency modulation DFB laser ranging system and a ranging method thereof, which solve the problems of complex system structure, extremely high requirement on linearity of a driving circuit and non-linear correction which often needs to rely on a complex digital predistortion algorithm or a photoelectric feedback loop and the like in the prior linear frequency modulation laser light source proposed in the background art. In order to achieve the aim, the invention is realized by the following technical scheme that the hybrid integrated non-correction linear frequency modulation DFB laser ranging system comprises a hybrid integrated packaging module, a first DFB laser, a second DFB laser, an optical circulator unit, GPPO high-frequency radio frequency interfaces and an independent regulation and control unit, The first DFB laser, the second DFB laser and the optical circulator unit are packaged in the hybrid integrated packaging module, and