4 results about "Optical heterodyne detection" patented technology

Modulated ringdown comb interferometry (MRCI) combines optical-frequency-comb spectroscopy with massively parallel optical heterodyne detection to simultaneously detect all of the comb lines of the optical frequency comb without spectral overlap. To perform MRCI, an optical frequency comb is coupled into an optical cavity. The optical frequency comb or optical cavity is modulated, at a modulation frequency, such that the optical cavity, in response to each comb line of the comb being swept across a resonance of the optical cavity, transmits one of a sequence of bursts. The sequence of bursts is combined with a multichromatic reference beam and photodetected to generate a sequence of interferograms having an intensity spectrum comprising several radio-frequency (RF) combs. The RF combs are all uniformly spaced by the modulation frequency but have unique offset frequencies. The RF combs are then fit to obtain best-fit decay times that collectively form a ringdown spectrum.

The application belongs to the technical field of optical sensing, and particularly relates to a high-resolution wavelength demodulation device based on laser beat frequency technology, the main structure of which comprises a reference light path and a sensing light path connected with a measuring light path respectively; the measuring light path, the reference light path and the sensing light path are connected with the measuring light path respectively, a gas molecule absorption line is introduced as a reference frequency, laser frequency measurement is reduced from a terahertz wave band to a low-frequency wave band which is easy to measure through an optical heterodyne detection scheme, high-resolution measurement is carried out through an oscilloscope and a frequency meter, and the device has extremely high resolution and long-term stability; the device has the advantages of simple structure, high resolution, good stability, fast response speed, high signal-to-noise ratio and the like, and is suitable for demodulating high-precision optical resonant cavity sensors.

The application provides a laser radar system based on heterodyne detection, comprising: a parallel chaotic signal emission module, which is used for emitting a parallel chaotic probe light signal and a local oscillator light signal corresponding to the parallel chaotic probe light signal; a spatial light transceiver module, which is used for emitting the parallel chaotic probe light signal into a detection area and simultaneously receiving a return light signal reflected by a target object in the detection area; a detection processing module, which is used for performing optical heterodyne detection on the return light signal, the parallel chaotic probe light signal and the local oscillator light signal, determining a detection difference frequency electric signal and a local oscillator reference difference frequency electric signal; and a digital signal processing module, which is used for performing correlation detection on the detection difference frequency electric signal and the local oscillator reference difference frequency electric signal, and determining detection information of the target object. The laser radar system greatly improves the anti-interference capability, can realize wide-field-range parallel high-resolution rapid detection and long-distance detection under the eye-safe power.

The present application relates to an optical heterodyne detection method based on a triangular stepped frequency modulation pulse signal, comprising the following steps: Step 1, generating an initial pulse signal; Step 2, generating a triangular stepped frequency modulation pulse signal: circulatingly processing the initial pulse signal through an optical fiber frequency shift delay loop, and making the frequency of the pulse signal increase first and then decrease at a fixed step by means of an arbitrary waveform generator to generate a triangular stepped frequency modulation pulse signal; The present invention can realize the increase first and then decrease of the frequency of the triangular stepped frequency modulation pulse signal by using the optical fiber frequency shift delay loop. By introducing a frequency difference and a fixed delay, the heterodyne signal after interference can carry vibration information, and the triangular stepped frequency modulation pulse signals generated by the optical fiber frequency shift delay loop all enter the unbalanced Michelson interferometer along the output end of the coupler, realizing the transmission of the heterodyne detection signal along the same optical fiber, thereby reducing the noise and interference of the transmission optical fiber and enabling the detection of vibration signals with high precision and in a large range.