11 results about "Polarization controller" patented technology

The invention relates to a fiber laser. An all-fiber dual-ring laser is formed by a semiconductor laser, an active fiber, a wavelength division multiplexer, a polarization controller, a fiber isolator and a saturable absorber based on graphene. The fiber laser is characterized in that the saturable absorber is shared to realize the output of dual-wavelength synchronous Q-switched pulse. The fiber laser is low in energy loss, compact and simple in structure and simple and convenient in operation, and has extremely great application advantages in fiber communications, non-linear frequency conversion, multi-wavelength pumping detection spectrums and Raman scattering spectrums.

The invention provides a multi-parameter measuring device based on a double-clad optical fiber. The device comprises a light source 1, a single-mode optical fiber 2, a polarizer 3, a polarization controller 4, the double-clad optical fiber 5 with a tilted grating 6 and a signal demodulator 7 which are connected in sequence. The double-clad optical fiber is provided with an inner cladding and an outer cladding, and the tilted grating is engraved on a fiber core. Light emitted by the light source forms a comb-shaped transmission spectrum after passing through the tilted grating, and the transmission spectrum comprises a Bragg resonance peak, an inner cladding resonance peak and an outer cladding resonance peak. When the external environment of the tilted grating changes, the transmission spectrum of the tilted grating changes, and real-time detection of parameters such as temperature, bending, axial strain and refractive index is realized by monitoring the changes of the wavelength and intensity of the resonance peaks, which has the advantages of small size, quick response, high sensitivity and the like.

The present invention relates to laser technology and nonlinear optical field, and provides an all-fiber femtosecond laser aiming at the shortcomings of existing lasers such as average output power, low peak power, high mode-locking threshold, wide pulse or complex structure. The laser includes pump light source, wavelength division multiplexer, gain fiber, low dispersion small mode field nonlinear fiber, polarization beam splitter, band pass filter and polarization controller. The mode field diameter of low dispersion small mode field nonlinear optical fiber is <= 4. 2 [mu]m; The bandpass filter comprises a polarization dependent isolator, a polarization maintaining fiber and a polarizer. Polarization-dependent isolator fused to the polarized optical axis of the polarization-maintaining optical fiber at an angle of 45 DEG; A wavelength division multiplexer, a gain optical fiber, a low dispersion small mode field nonlinear optical fiber, a polarization beam splitter, a polarization dependent isolator, a polarization maintaining optical fiber and a polarizer are sequentially connected to form an all optical fiber ring cavity; A polarization controller is located between the polarization beam splitter and the polarization dependent isolator and/or between the polarizer and the wavelength division multiplexer.

The invention discloses an all-optical sampler, comprising a continuous laser which is used for generating continuous signal light; an optical modulator which is driven by a radio frequency signal and is used for modulating an analog radio frequency signal through combination with the signal light, thereby generating continuous analog signal light; a polarization controller which is used for controlling a polarization state of the analog signal light; a first coupler which is used for allocating the low-power analog signal light into two ways of light according to a proportion; a Mach-Zehnder interferometer, wherein a first interference arm and a second interference arm of the Mach-Zehnder interferometer are used for receiving the two ways of analog signal light allocated by the first coupler; and a second coupler which is used for receiving the analog signal light output by the Mach-Zehnder inter-ferometer, coupling the analog signal light and then outputting sample signal light. According to the all-optical sampler, through utilization of cross-phase modulation effect of pump light for the analog signal light, the phase difference of the signals on the two interference arms is changed, so transmittance of the signals is changed; when the pump light exists, the signals are transmitted; and when the pump light does not exist, the signal transmittance is 0, thereby sampling the signals.

An instantaneous frequency measurement system based on a differential optical time stretching principle relates to the field of microwave photonics, ultrafast measurement and real-time measurement, and is characterized in that a light output end of a pulse laser light source is connected with one end of a dispersion module I, the other end of the dispersion module I is connected with an input end of a polarization controller, and an output end of the polarization controller is connected with a light input end of a modulator; one output port of the modulator is connected with the input end of the optical circulator I; the other output port of the modulator is connected with the input end of the optical circulator I, the other output port of the modulator is connected with the input end of the optical circulator II, the port of the optical circulator I and the port of the optical circulator II are respectively connected with one end of the dispersion module II, and the port of the optical circulator I and the port of the optical circulator II are respectively connected with the first optical input port and the second optical input port of the balance detector. The system can relieve the pressure of rear-end electronic equipment, eliminates the distortion influence of uneven laser pulse envelope on measurement through differential detection, and can perform real-time and accurate ultrafast measurement on multi-frequency signals.

The invention discloses a distance measuring device, which comprises a light source, a polarization controller, a first electro-optical modulator, a second electro-optical modulator, an optical circulator, a coupler, a 1/4 wave plate, a reflector, an analyzer, a photoelectric detector, a low-pass filter, a signal source, a first automatic gain amplifier, a second automatic gain amplifier and a measurement control unit. The invention further discloses a distance measuring method, which comprises the steps of outputting sinusoidal signals with the frequency changing continuously by using the signal source, controlling the first electro-optical modulator and the second electro-optical modulator to modulate the measurement light at the same time, and measuring demodulation waveform parametersto calculate the distance to be measured. The device is simple in structure and high in environmental adaptability, measurement errors caused by non-reciprocal and non-flat electrical characteristicsof the modulator can be effectively suppressed, and large-dynamic-range high-precision absolute distance measurement can be realized at the same time.