4 results about "Mode hopping" patented technology

The present invention provides a laser radar device that can detect mode hopping even when the signal contains noise, and can control the laser light source to restore its shifted vertical mode after mode hopping occurs. [Solution] The FMCW type laser radar device 1 comprises a laser light source 2, an optical interference unit 61 that splits and propagates the laser light from the laser light source 2 into two, and an IQ signal generation unit 62 that outputs a beat signal via the optical interference unit 61. In the laser radar device 1, an instantaneous phase calculation unit 64 calculates the instantaneous phase of the beat signal, a mode hop determination unit 65 detects discontinuities in the instantaneous phase, and determines whether or not a mode hop has occurred in the laser light source 2 based on the detection result. If the laser radar device 1 determines that a mode hop has occurred, the light source control unit 7 performs feedback control of the oscillation mode of the laser light source 2 so that the change in instantaneous phase before and after the determination of the occurrence of a mode hop is less than or equal to a predetermined value.

This specification relates to an optical particle counter, a method for using an optical particle counter, and a method for reducing particle counting errors during use of an optical particle counter. The method includes placing an optical isolator between a laser and a flow cell to allow laser light to pass through the flow cell and to reduce the intensity of light returned to the laser as optical feedback that could cause mode hopping.

The application provides a tunable laser mode hopping suppression system and method and a tunable laser, and relates to the technical field of precision optics, and comprises a power detection module, a displacement detection module and a cooperative compensation module.The power detection module is used for separating sample light of a predetermined proportion from laser output light, and determining laser output power based on the sample light.The displacement detection module is used for measuring an actual driving displacement amount of a micro driver.The cooperative compensation module is used for determining whether mode hopping occurs according to a first derivative of the laser output power and a driving voltage of the micro driver, calculating a deviation amount between a theoretical displacement driving amount corresponding to a current injection voltage of the micro driver and the actual driving displacement amount when it is determined that mode hopping occurs, determining compensation coefficients of injection current compensation and injection voltage compensation according to the deviation amount, and adjusting an injection current of a laser diode and an excitation voltage of the micro driver according to the compensation coefficients of the injection current compensation and the injection voltage compensation.The application realizes mode hopping detection and suppression when the laser works.