Ultrastable laser system based on polarization-maintaining optical fiber

An ultrastable laser system based on a polarization-maintaining optical fiber, comprising

• a laser device (1),
• a first acousto-optic modulator (2),
• a first beam splitter (3),
• a second acousto-optic modulator (4),
• a polarizer (5),
• an optical fiber interferometer, the optical fiber interferometer comprising a second beam splitter (6), an optical fiber delay line (7), a third acousto-optic modulator (8), and a beam combiner (9),
• a polarization beam splitter (10),
• a first photoelectric detector (11),
• a second photoelectric detector (12),
• a first frequency mixer (13),
• a second frequency mixer (14),
• a radio frequency synthesizer (15), and
• a servo feedback circuit (16),
• wherein an output light of the laser device (1) is split into two beams after sequentially passing through the first acousto-optic modulator (2) and the first beam splitter (3);
• one beam enters the second acousto-optic modulator (4), and the other beam enters the second beam splitter (6) after being polarized by the polarizer (5);
• a first output end of the second beam splitter (6) is connected with a first input end of the beam combiner (9) in a manner of offset fusion splicing of an optical fiber, and a second output end of the second beam splitter (6) is connected with a second input end of the beam combiner (9) in the manner of offset fusion splicing of the optical fiber after sequentially passing through the optical fiber delay line (7) and the third acousto-optic modulator (8);
• the beams enter the polarization beam splitter (10) after being combined by the beam combiner (9), and the light is split into a first beam of light and a second beam of light by the polarization beam splitter (10) so as to be output;
• the first beam of light passes through the first photoelectric detector (11) to obtain a first beat frequency signal and is radiated to an RF end of the first frequency mixer (13), and the second beam of light passes through the second photoelectric detector (12) to obtain a second beat frequency signal and is radiated to an RF end of the second frequency mixer (16);
• the radio frequency synthesizer (15) outputs three paths of radio frequency signals, wherein the first path enters the third acousto-optic modulator (8) so as to be used for laser frequency shift;
• the second path enters an LO end of the first frequency mixer (13) to obtain a first frequency discrimination signal and enters the servo feedback device (16) to form a feedback loop for stabilizing the frequency of the laser device;
• and the third path enters an LO end of the second frequency mixer (14) to obtain a second frequency discrimination signal and enters the second acousto-optic modulator (4) so as to be modulated to output ultrastable laser.