33results about How to "Polarization stabilization" patented technology

The invention provides a phase encoder / decoder and a quantum key distribution system. The phase encoder / decoder comprises a Sagnac ring structure, that is, the Sagnac ring structure is adopted to replace a back and forth structure for high-speed phase loading, fractions perpendicular to two polarizations of a same pulse pass through a phase modulator for a single time simultaneously, and not onlyis a characteristic of polarization stabilization achieved, but also advantages of high speeds and high efficiency are achieved. According to the phase encoder / decoder, a Faraday-Sagnac-Michelson encoder is adopted as a core phase encoding quantum key distribution system, one-way high-speed safety key distribution can be achieved, and the phase encoder / decoder has the advantages of channel deviation disturbance resistance and high encoding rates are achieved.

The invention provides a laser, which comprises at least one pump light emitting device, an optical fiber beam combiner, a grain optical fiber, a first aligner, a mold locking device, a second aligner and an output lens, wherein a first polarization beam-splitting device is arranged between the first aligner and the mold locking device on the laser; a second polarization beam-splitting device is arranged between the second aligner and the output lens on the laser; adjacent optical devices are connected by adopting polarization-preserving optical fibers. The laser having a polarization-preserving optical fiber structure is high in stability. Linearly polarized light is transmitted through the polarization-preserving optical fibers, so that the influence of vibration on a light path caused by temperature change is avoided. Moreover, the mold locking device can be used for stably absorbing a part of energy and reflecting laser pulse generated after stable mold locking through the polarization beam-splitting devices.

The invention discloses an infrared controllable partially polarized radiation source, which comprises a temperature controller, a black body, an infrared collimator, an infrared polarizer and a reflector; the temperature controller controls the temperature of the black body, and the black body emits radiation of different wavelengths corresponding to different temperatures Infrared rays; the infrared collimator collimates the infrared rays emitted by the black body; the infrared polarizer turns the collimated infrared rays into linearly polarized radiation; the reflector changes the linearly polarized radiation in two mutually perpendicular vibrations according to the incident angle of the linearly polarized radiation The phase difference in the direction, and reflect and output part of the polarized radiation corresponding to the polarization state. The above-mentioned infrared controllable partially polarized radiation source can produce infrared partially polarized radiation with different polarization states and known polarization parameters, and can generate partially polarized radiation within a large range of polarization degrees. The polarization state of the partially polarized radiation is controllable and the polarization degree is known. , and the degree of polarization is stable and the precision is high under certain environmental conditions, and it is suitable for polarization calibration of infrared polarization imaging systems.

The invention discloses an optical fiber depolarizer with a single-mode fiber serving as a delay line. The optical fiber depolarizer comprises an optical fiber branching device, a first polarization beam splitter, the single-mode fiber, a faraday rotary reflector and a second polarization beam splitter. A beam combination port of the first polarization beam splitter and the faraday rotary reflector are connected to two ends of the single-mode fiber respectively to form a delay optical path, and two beam splitting ports of the first polarization beam splitter serve as an input port and an output port of the delay optical path respectively. The optical fiber branching device divides input light into two branches, one branch of light is directly inputted into one of beam splitting ports of the second polarization beam splitter, the other branch of light passes through the delay optical path to be inputted into the other beam splitting port of the second polarization beam splitter, and depolarized light is outputted from a beam combination port of the second polarization beam splitter. Cost of the optical fiber depolarizer is reduced by using the normal single-mode fiber as the delay line; and the polarization state is kept stable after the light passes through the delay optical path, and accordingly the optical fiber depolarizer can operate stably.

The invention relates to a quantum communication system without polarization feedback and a quantum safe direct communication method. The quantum communication system of the invention comprises a communication receiving module, a communication sending module and a quantum channel between the two parties; a first phase modulation in the communication receiving module The device can prepare photons in four random phases for the communication sending module, and obtain qubits by detecting the photons returned by the communication sending module through a single photon detector; the communication sending module includes an encoding optical path module and a security detection module. The invention utilizes the consistency of the coded optical path and the stability of the safety detection optical path to avoid the influence of polarization drift caused by birefringence.