7 results about "Relative intensity noise" patented technology

The optical interferometer comprises: a broadband light source that outputs a first light in a given frequency domain with suppressed relative intensity noise (RIN); a wavelength divider that divides the first light into a first component and a second component with a center wavelength different from the first component and outputs the second component; a first optical path that propagates the first component output from the wavelength divider; a second optical path that propagates the second component output from the wavelength divider; and a wavelength synthesizer that combines the first component propagating in the first optical path and the second component propagating in the second optical path as a second light output.

The invention discloses an all-normal dispersion super-continuum spectrum driven resonant optical gyroscope and a working method thereof, and belongs to the field of optical gyroscopes. The input end of the mode-locked laser ML is connected to a left port of the full-normal dispersion photonic crystal fiber ANDi-PCF, input ports of the full-normal dispersion photonic crystal fiber ANDi-PCF and the photoelectric detector PD are connected to two left ports of the circulator CIR respectively, and a right port of the circulator CIR is connected with a left port of the multifunctional integrated optical chip MIOC. And two ports on the right side of the multifunctional integrated optical chip MIOC are respectively connected with two ports of the waveguide ring resonator WRR. Based on the resonance mode of the full-normal dispersion super-continuum spectrum excitation waveguide ring resonator, the influence of relative intensity noise and shot noise on the gyroscope performance is further reduced by using the broadband and smooth light source spectrum pattern, and finally the angle random walk of the gyroscope is promoted.

The invention provides a high-power low-intensity-noise semiconductor laser chip and a laser, a lower waveguide layer is arranged above an N-type substrate, two optical limiting layers are arranged above the lower waveguide layer, an active layer is clamped between the two optical limiting layers, a grating layer is arranged on the optical limiting layers, and the grating layer is arranged on the N-type substrate. An upper cladding layer is arranged on the grating layer, and a contact metal layer is arranged on the upper cladding layer; the grating layer is integrated with a lambda / 4 phase shift structure; and the semiconductor laser chip adopts a ridge waveguide structure. Compared with a traditional narrow ridge waveguide DFB laser, the narrow ridge waveguide DFB laser has the advantages that under the short cavity length condition, the output power exceeding hundreds of milliwatts, low relative intensity noise, high side mode rejection ratio and the narrow line width of about hundreds of kHz are achieved, and meanwhile the relaxation oscillation frequency of the GHz level is achieved. The laser chip shows good power linearity and single-mode stability in a lower normal temperature range, and is suitable for the fields of high-speed optical fiber communication, microwave photonics and the like with strict requirements on power and noise performance.

This invention discloses a microwave photonic image suppression mixer chip and mixing method. The chip integrates a grating coupler, a 1×2 MMI, two single-input dual-output single-ended push-pull silicon-based carrier depletion modulators, two 2×2 MMIs, and two GeSi balanced photodetectors. This scheme, based on a single dual-parallel modulator structure combined with a balanced detector structure, can achieve both orthogonal intermediate frequency (IF) signal output and image suppression. The system structure is simple and highly stable. It eliminates the need for a narrowband optical bandpass filter, resulting in a large system operating bandwidth. By employing a balanced detector structure, the system's relative intensity noise and RF leakage terms are suppressed, while the output IF term gain is increased, leading to a higher system signal-to-noise ratio.

The application provides a balanced optical detector assembly for a fiber-optic gyroscope, which comprises a pigtail, a photosensitive diode and a carrier thereof, a signal processing circuit, a packaging shell and a packaging cover; the packaging cover covers the packaging shell; the pigtail is aligned with a photosensitive surface on the photosensitive diode and the carrier thereof after passing through the packaging shell; the photosensitive diode and the carrier thereof and the signal processing circuit are fixed on a mounting surface of the packaging shell; electrical communication is achieved between the photosensitive diode and the carrier thereof and the signal processing circuit and between the signal processing circuit and lead wires of the packaging shell by wire bonding. The application realizes perfect balance of signal light and reference light and effectively reduces relative intensity noise of a light source of the fiber-optic gyroscope.

The application discloses a kind of multi-path parallel balanced receiving photoelectric detector, belong to broadband fast electric field detection technical field, the photoelectric detector includes by 1 / M (M≥2) polarization beam splitter structure of optical beam splitter, by M group balanced photodiode pair photoelectric detection structure, by M current-voltage conversion structure of transimpedance amplification circuit and 1 / M radio frequency power combining structure.The node of every two photodiodes is connected, to output signal in the form of "current self reduction", the differential current signal of two photodiodes is converted into voltage signal using transimpedance amplifier, as a radio frequency output.M path detection signal is through power divider.The light signal carrying modulation signal is first through optical beam splitting to carry out parallel balanced detection, then power is synthesized by radio frequency, can enhance the saturation optical power tolerance of detector whole, and relative intensity noise in system is inhibited to a certain extent, so signal-to-noise ratio of detection signal can be improved.

The application discloses a kind of optical frequency comb receiving system noise digital cancellation methods, specifically related to digital signal processing technical field, by beam splitter, femtosecond laser is divided into signal path and noise reference path and synchronous acquisition. After Fourier transform to two-way data, the effective spectrum is divided into initial frequency band and the projection coefficient of each section is calculated. According to the relative difference of adjacent frequency band projection coefficient, the frequency band division is dynamically adjusted, and the adaptive frequency band is formed. In each adaptive frequency band, the projection of signal path on reference path is subtracted, the noise cancellation is realized, and finally the time domain signal is obtained by spectrum reorganization and inverse transform;The application is synchronous acquisition and dynamic frequency band division by signal path and noise reference path, effectively suppresses light source relative intensity noise, and improves signal quality;Digital processing mode is used, without complex hardware adjustment, to reduce system cost;Through adaptive frequency band division, environmental changes are adapted, and noise cancellation stability is improved.