CN103269251B - Light differential quadrature phase shift keying demodulator - Google Patents
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Abstract
The invention discloses a kind of light differential quadrature phase shift keying demodulator. Comprise: the first input optical collimator, the second input optical collimator, the first beam splitter, the second beam splitter, right-angle prism, the first output optical collimator, the second output optical collimator, the 3rd output optical collimator, the 4th output optical collimator, two input optical collimators are respectively used to that optical signal is become to collimated light and export the first beam splitter to; The first beam splitter is for carrying out transmission and reflection by the collimated light receiving; Right-angle prism is for carrying out the light beam receiving two secondary reflections and export the second beam splitter to; The second beam splitter is for carrying out transmission and reflection by the light beam receiving; Four output optical collimators are respectively used to the light beam receiving to converge rear output. Application the present invention, can make demodulator structure compactness, and volume is little, has good temperature stability.
Description
Technical Field
The present invention relates to a demodulator, and more particularly, to an optical differential quadrature phase shift keying demodulator.
Background
In a high-speed optical fiber transmission system (40G/100G), a Differential Quadrature Phase Shift Keying (DQPSK) signal modulation technique is commonly used, wherein DQPSK is a multi-level differential phase shift keying format, which represents transmitted bit information with four phase differences between adjacent symbols, and at a receiving end based on the differential phase modulation format, a demodulator is required to convert the phase modulation into intensity modulation so as to extract information in code and differential phases, and at present, the demodulator is generally implemented by using optical waveguide technology and Etalon technology design.
Among demodulators based on optical waveguide technology, the DQPSK demodulator is composed of two delay interferometers (DLIs) and two corresponding pairs of photodetectors, and its structure is shown in fig. 1. The method is characterized in that a 3dB coupler and two delay interferometers with the same delay are integrated by utilizing waveguide manufacturing, the delay of the delay interferometers is determined by the length difference of interference arms, the length difference delta L is selected according to the signal rate R to be demodulated, and the relation between the length difference delta L and the signal rate R is delta L = C/R, wherein C is the speed of light in the waveguide. The two delay interferometers generate a phase difference of 90 degrees through the pre-design of the arm lengths of the two delay interferometers or the subsequent processing, so that the demodulation of the DQPSK signal is realized. .
In the demodulator based on the Etalon technology, the time delay interferometer principle is also adopted, and the DQPSK demodulator is composed of two double-fiber collimators, two single-fiber collimators, two beam splitters, four Etalon and a coupler, and the structure of the DQPSK demodulator is shown in FIG. 2. The function that the two time delay interferometers have a phase difference of 90 degrees is realized by adjusting the length of any one of the four etalons.
Due to the characteristics of large insertion loss and polarization dependent loss in the aspect of optical waveguide technology performance and high refractive index temperature sensitivity, the optical demodulator based on the optical waveguide technology has high insertion loss and polarization dependent loss and needs more accurate temperature control, and the cost of the optical demodulator based on the optical waveguide technology is high due to the high price and large investment of equipment required by the optical waveguide technology. In addition, the demodulator based on the Etalon technology has the disadvantages that the two time delay interferometers cannot share devices, so that a large number of optical devices are used, the size is large, phase separation is realized by changing the length of Etalon, the process is complex, and the adjustment is difficult.
Disclosure of Invention
The invention aims to provide an optical differential quadrature phase shift keying demodulator which is compact in structure, small in size and good in temperature stability.
According to an aspect of an embodiment of the present invention, there is provided an optical differential quadrature phase shift keying demodulator including: a first input light collimator, a second input light collimator, a first beam splitter, a second beam splitter, a right angle prism, a first output light collimator, a second output light collimator, a third output light collimator, and a fourth output light collimator; wherein,
the first input light collimator and the second input light collimator are respectively used for converting the received optical signals into collimated light and outputting the two paths of optical signals to the first beam splitter; the first beam splitter is used for respectively transmitting and reflecting the two received optical signals and outputting two formed reflected beams and two transmitted beams; the right-angle prism is used for reflecting and outputting the two received transmitted beams twice; the second beam splitter is configured to transmit and reflect the two received reflected beams, output the two formed transmitted beams to the third output light collimator and the fourth output light collimator, and output the two formed reflected beams to the first output light collimator and the second output light collimator, respectively; and simultaneously transmitting and reflecting the two received reflected beams, respectively outputting the two formed transmitted beams to the first output light collimator and the second output light collimator, and respectively outputting the two formed reflected beams to the third output light collimator and the fourth output light collimator.
Preferably, the coupler is configured to equally divide the received optical signal and output the divided optical signal to the first input optical collimator and the second input optical collimator, respectively.
Preferably, the first input light collimator, the second input light collimator, and the first beam splitter constitute a vertically placed first cuboid, and the first beam splitter is a triangular prism equally divided by a diagonal line in the vertically placed first cuboid; the second beam splitter, the first output light collimator, the second output light collimator, the third output light collimator and the fourth output light collimator are combined into a second cuboid which is vertically placed on the first cuboid, the second beam splitter is an inverted triangular prism which is uniformly divided by diagonal lines in the vertically placed second cuboid, and the third output light collimator and the fourth output light collimator are embedded into the inverted triangular prism from the top surface of the inverted triangular prism along the vertically placed direction; the side surfaces of the triangular prism and the side surfaces of the inverted triangular prism are respectively plated with a light splitting film layer with a light splitting ratio of 50: 50; the plane of the light splitting film layer of the first light beam splitter is vertical to the plane of the light splitting film layer of the second light beam splitter, and the planes of the light splitting film layers of the first light beam splitter and the second light beam splitter are vertical to the same transmitted light incidence plane; the first input light collimator, the second input light collimator, the first output light collimator, and the second output light collimator are arranged along a vertical direction; and the side surface of the right-angle prism is superposed with the side surface of a cuboid block consisting of the first beam splitter and the second beam splitter along the vertical placement direction.
Preferably, the first beam splitter and the second beam splitter have the same size parameter, and the first beam splitter has the same size parameter; the length of the side edge of the right-angle prism is equal to the width of the vertically placed first cuboid; the length of the hypotenuse of the right-angle prism is equal to the sum of the height of the vertically placed first cuboid and the height of the vertically placed second cuboid.
Preferably, the top surface of the first beam splitter and the bottom surface of the second beam splitter are tightly or optically glued together, and the side surface of the right-angle prism and the side surface of the cuboid block composed of the first beam splitter and the second beam splitter are tightly or optically glued together.
Preferably, the coupler is located on the left side of the first input light collimator and the second input light collimator, the second output light collimator, the first output light collimator, the second input light collimator and the first input light collimator are sequentially arranged along a vertical direction, and are located on the right side of a cuboid block composed of the first beam splitter and the second beam splitter, the axial directions of the first input light collimator, the second input light collimator, the first output light collimator and the second output light collimator are perpendicular to the cubic direction, the axial directions of the third output light collimator and the fourth output light collimator are sequentially arranged along a horizontal direction, and the axial directions of the third output light collimator and the fourth output light collimator are perpendicular to the top surface of the second beam splitter.
Preferably, said coupler, said first input light collimator, said first beam splitter, said second beam splitter, said right angle prism, said second output light collimator, said third output light collimator constitute a time-lapse interferometer; the coupler, the second input light collimator, the first beam splitter, the second beam splitter, the right angle prism, the first output light collimator, and the fourth output light collimator constitute another time-delay interferometer.
Preferably, the right-angle prism reflects the first transmitted light beam and the second transmitted light beam twice to form four reflecting areas, and any one of the four reflecting areas is polished to be reduced by a quarter wavelength.
Preferably, the first input light collimator is configured to convert the first optical signal equally divided by the coupler into first collimated light, and output the first collimated light to the first beam splitter; the second input light collimator is used for changing a second optical signal equally divided by the coupler into second collimated light and outputting the second collimated light to the first beam splitter; the first beam splitter is configured to transmit and reflect the first collimated light, and output the obtained first reflected light beam and the obtained first transmitted light beam to the second beam splitter and the right-angle prism respectively; transmitting and reflecting the second collimated light, and respectively outputting the obtained second reflected light beam and second transmitted light beam to the second beam splitter and the right-angle prism; the right-angle prism is used for reflecting the first transmitted beam and the second transmitted beam twice respectively and outputting the reflected beams to the second beam splitter; the second beam splitter is configured to transmit and reflect the first reflected light beam, and output a third obtained transmitted light beam and a third obtained reflected light beam to the third output light collimator and the second output light collimator, respectively; transmitting and reflecting the second reflected light beam, and outputting a fourth transmitted light beam and a fourth reflected light beam to the fourth output light collimator and the first output light collimator respectively; simultaneously transmitting and reflecting the received first transmitted light beam, and respectively outputting the obtained fifth transmitted light beam and the fifth reflected light beam to the second output light collimator and the third output light collimator; and transmitting and reflecting the received second transmitted light beam, and outputting the obtained sixth transmitted light beam and sixth reflected light beam to the first output light collimator and the fourth output light collimator respectively.
Preferably, the fifth transmitted beam and the third reflected beam have a time delay difference matched with one half of the speed of the signal to be demodulated; the fifth reflected light beam and the third transmitted light beam have time delay difference matched with one half of the speed of a signal to be demodulated; the sixth transmitted light beam and the fourth reflected light beam have time delay difference matched with one half of the speed of a signal to be demodulated; and the time delay difference matched with one half of the speed of the signal to be demodulated is formed between the sixth reflected light beam and the fourth transmitted light beam.
In the technical scheme of the embodiment of the invention, the top surface of the first beam splitter and the bottom surface of the second beam splitter are tightly glued or optically glued together, the side surface of the right-angle prism is tightly glued or optically glued together with the side surface of a cuboid block consisting of the first beam splitter and the second beam splitter, and the two time delay interferometers are formed by sharing the right-angle prism, the first beam splitter and the second beam splitter, so that the volume is small, the structure is compact, and the production cost is reduced due to the use of the right-angle prism made of glass materials; the 90-degree phase difference between the two time delay interferometers is realized by polishing and thinning a quarter wavelength of a first transmission beam and a second transmission beam at any position of four reflection areas which are respectively reflected twice in a diameter prism, a material with a higher thermal expansion coefficient is not required to be added into a demodulator, the temperature is adjusted by attaching a heating resistor, and the optical path difference is changed, so that the two time delay interferometers have good temperature stability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is to be understood that the drawings in the following description are merely exemplary of the invention and that other embodiments and drawings may be devised by those skilled in the art based on the exemplary embodiments shown in the drawings.
FIG. 1 is a schematic diagram of a DQPSK demodulator based on optical waveguides;
FIG. 2 is a schematic diagram of a DQPSK demodulator based on etalon;
FIG. 3 is a schematic perspective view of an optical differential quadrature phase shift keying format demodulator according to a first embodiment of the present invention;
FIG. 4 is a diagram illustrating an optical DPSK format demodulator according to a first embodiment of the present invention;
fig. 5 is a schematic structural diagram of an optical differential quadrature phase shift keying format demodulator according to a second embodiment of the present invention.
Detailed Description
The technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 3 is a schematic perspective view of an optical differential quadrature phase shift keying format demodulator according to a first embodiment of the present invention. Referring to fig. 3, comprising: a first input light collimator 301, a second input light collimator 302, a first output light collimator 303, a second output light collimator 304, a third output light collimator 305, a fourth output light collimator 306, a first beam splitter 307, a second beam splitter 308, a right angle prism 309.
The first input light collimator 301, the second input light collimator 302, and the first beam splitter 307 form a vertically placed first cuboid, and the first beam splitter 307 is a triangular prism equally divided by a diagonal line in the vertically placed first cuboid. The second beam splitter 308, the first output light collimator 303, the second output light collimator 304, the third output light collimator 305 and the fourth output light collimator 306 form a second cuboid vertically placed on the first cuboid, the second beam splitter 308 is an inverted triangular prism equally divided by diagonal lines in the vertically placed second cuboid, and the third output light collimator 305 and the fourth output light collimator 306 are embedded into the inverted triangular prism from the top surface of the inverted triangular prism along the vertical placement direction. And the side surfaces of the triangular prism and the side surfaces of the inverted triangular prism are respectively plated with a light splitting film layer with a light splitting ratio of 50: 50. The plane of the light splitting film layer of the first beam splitter 307 and the plane of the light splitting film layer of the second beam splitter 308 are perpendicular to each other and perpendicular to the same incident plane of the transmitted light. The first input light collimator 301, the second input light collimator 302, the first output light collimator 303, and the second output light collimator 304 are arranged in a vertical direction. The side surface f of the right-angle prism 309 coincides with the side surface of the rectangular parallelepiped block composed of the first beam splitter 307 and the second beam splitter 308 in the standing direction.
Preferably, the first beam splitter 307 and the second beam splitter 308 have equal size parameters, and the first beam splitter 307 has equal size parameters, and the first beam splitter 307 and the second beam splitter 308 have equal sizes and match the size of the right angle prism 309, that is, the length e of the side edge of the right angle prism 309 is equal to the width a of the first cuboid standing vertically, and the length d of the hypotenuse of the right angle prism 309 is equal to the sum of the height b of the first cuboid standing vertically and the height c of the second cuboid standing vertically.
Preferably, the top surface of the first beam splitter 307 is glued or optically bonded to the bottom surface of the second beam splitter 308, and the side surface f of the right angle prism 309 is glued or optically bonded to the side surface of the cuboid block consisting of the first beam splitter 307 and the second beam splitter 308.
Fig. 4 is a schematic structural diagram of an optical differential quadrature phase shift keying format demodulator according to a first embodiment of the present invention. Referring to fig. 4, including: 3dB coupler 401, first input light collimator 402, second input light collimator 403, first output light collimator 404, second output light collimator 405, third output light collimator 406, fourth output light collimator 407, first beam splitter 408, second beam splitter 409, right angle prism 410.
The 3dB coupler 401 is configured to equally divide the received optical signal, and output the divided optical signal to the first input optical collimator and the second input optical collimator respectively; the first input light collimator 402 is configured to convert the first optical signal into first collimated light, and output the first collimated light to the first beam splitter 408; the second input light collimator 403 is used to convert the first optical signal into first collimated light, and output the first collimated light to the first beam splitter 408; the first beam splitter 408 is configured to transmit and reflect the first collimated light, and output the obtained first reflected light beam and the obtained first transmitted light beam to the second beam splitter 409 and the right-angle prism 410, respectively; transmitting and reflecting the second collimated light, and outputting the obtained second reflected light beam and second transmitted light beam to a second beam splitter 409 and a right-angle prism 410 respectively; the right-angle prism 410 is configured to reflect the first transmitted beam and the second transmitted beam twice respectively and output the reflected beams to the second beam splitter 409; the second beam splitter 409 is configured to transmit and reflect the first reflected light beam, and output a third obtained transmitted light beam and a third obtained reflected light beam to the third output light collimator 406 and the second output light collimator 405, respectively; transmitting and reflecting the second reflected light beam, and outputting the obtained fourth transmitted light beam and fourth reflected light beam to a fourth output light collimator 407 and the first output light collimator 404, respectively; simultaneously transmitting and reflecting the received first transmitted beam, and outputting the obtained fifth transmitted beam and fifth reflected beam to a second output light collimator 405 and a third output light collimator 406, respectively; transmitting and reflecting the received second transmitted light beam, and outputting the obtained sixth transmitted light beam and sixth reflected light beam to the first output light collimator 404 and the fourth output light collimator 407, respectively; the first output light collimator 404, the second output light collimator 405, the third output light collimator 406, and the fourth output light collimator 407 are respectively configured to converge and output the received light beams.
Preferably, the 3dB coupler 401 is located at the left side of the first input light collimator 402 and the second input light collimator 403, the second output light collimator 405, the first output light collimator 404, the second input light collimator 403 and the first input light collimator 402 are sequentially arranged along the vertical direction and located at the right side of the cuboid block composed of the first beam splitter 408 and the second beam splitter 409, the axial directions of the first input light collimator 402, the second input light collimator 403, the first output light collimator 404 and the second output light collimator 405 are perpendicular to the vertical direction, the axial directions of the third output light collimator 406 and the fourth output light collimator 407 are sequentially arranged along the horizontal direction, and the axial directions of the third output light collimator 406 and the fourth output light collimator 407 are perpendicular to the top surface of the second beam splitter 409.
The operating principle of the optical differential quadrature phase shift keying format demodulator according to the first embodiment of the present invention is as follows: the received DQPSK optical signal is equally divided into a first optical signal and a second optical signal by a coupler 401, the first optical signal is outputted to a first optical beam splitter 408 by a first input optical collimator 402, and reflected and transmitted to obtain a first transmitted beam T and a first reflected beam R with equal energy, the first reflected beam R is outputted to a second optical beam splitter 409, the first transmitted beam T is outputted to a right-angle prism 410, and outputted to the second optical beam splitter 409 after twice reflection, the first reflected beam R is outputted to the second optical beam splitter 409, and reflected and transmitted to obtain a third reflected beam RR and a third transmitted beam RT, the first beam T is outputted to the second optical beam splitter 409, and reflected and transmitted to obtain a fifth reflected beam TR and a fifth transmitted beam TT, the fifth transmitted beam TT and the third reflected beam RR are coherent to a port of the second output optical collimator 405 for output, the third transmitted light beam RT and the fifth reflected light beam TR are output coherently with the third output light collimator 406.
Similarly, the second optical signal is output by the second input optical collimator 403 to the first optical beam splitter 408, reflected and transmitted, and split into a second transmitted beam T1 and a second reflected beam R1 of equal energy. The second reflected beam R1 is output to the second beam splitter 409, the second transmitted beam T1 is output to the right-angle prism 410, and is output to the second beam splitter 409 after two reflections, the second reflected beam R1 is output to the second beam splitter 409 to be reflected and transmitted, and a fourth reflected beam RR1 and a fourth transmitted beam RT1 are obtained, and the second transmitted beam T1 is output to the second beam splitter 409 to be reflected and transmitted, and a sixth reflected beam TR1 and a sixth transmitted beam TT1 are obtained. The sixth transmitted beam TT1 and the fourth reflected beam RR1 are output coherently with the first optical output collimator 404 port, and the fourth transmitted beam RT1 and the sixth reflected beam TR1 are output coherently with the fourth output optical collimator 407 port.
Interference is formed between the fifth transmitted light beam TT and the third reflected light beam RR, between the sixth transmitted light beam TT1 and the fourth reflected light beam RR1, between the third transmitted light beam RT and the fifth reflected light beam TR, and between the fourth transmitted light beam RT1 and the sixth reflected light beam TR1, two optical paths forming the interference have delay differences matched with the signal rate to be demodulated, and the difference is DeltaL =2L1n, Δ L are optical path differences between the fifth transmitted beam TT and the third reflected beam RR, and between the third transmitted beam RT and the fifth reflected beam TR, L1Is the geometric length of the transmitted beam in the first beam splitter 408 and the right angle prism 410, n is the refractive index (constant) of the optical signal, al' =2L2n, Δ L' are optical path differences between the sixth transmitted light beam TT1 and the fourth reflected light beam RR1, and between the fourth transmitted light beam RT1 and the sixth reflected light beam TR1, L2Is the geometric length of the transmitted beam in the first beam splitter 408 and the right angle prism 410, and n is the refractive index (constant) of the optical signal since L is geometric1=L2The optical path length differences between the fifth transmitted beam TT and the third reflected beam RR, between the sixth transmitted beam TT1 and the fourth reflected beam RR1, between the third transmitted beam RT and the fifth reflected beam TR, and between the fourth transmitted beam RT1 and the sixth reflected beam TR1 are equal, and the adjustment of the time delay difference is determined by the thicknesses of the first beam splitter 408, the second beam splitter 409, and the rectangular prism 410 under the condition that the rate of the signal to be demodulated is determined.
Preferably, the first input light collimator 402, the second output light collimator 405, the third output light collimator 406 and the first beam splitter 408, the second beam splitter 409, the right angle prism 410 constitute one time delay interferometer, while the second input light collimator 403, the first output light collimator 404, the fourth output light collimator 407 and the first beam splitter 408, the second beam splitter 409, the right angle prism 410 constitute another time delay interferometer.
Preferably, the two time-lapse interferometers have a phase shift of 90 degrees, and the 90-degree phase shift is formed by polishing the first transmitted beam and the second transmitted beam to be reduced by a quarter wavelength at any one of four reflection regions P1, P2, P3, P4, which are reflected twice in the rectangular prism 410, respectively.
Further, the electrical domain demodulation of the DQPSK signal can be realized by replacing the first output optical collimator 404, the second output optical collimator 405, the third output optical collimator 406, and the fourth output optical collimator 407 with PD detectors to receive the optical signal and differentially output.
The operating principle of the optical differential quadrature phase shift keying format demodulator according to the second embodiment of the present invention is as follows: the DQPSK optical signal is equally divided into a first optical signal and a second optical signal by the coupler 501, the first optical signal is outputted to the first optical beam splitter 508 through the first input optical collimator 502, reflected and transmitted, and divided into a first transmitted beam T 'and a first reflected beam R' with equal energy, the first transmitted beam T 'is outputted to the second optical beam splitter 409, the first reflected beam R' is outputted to the right-angled prism 510, reflected twice and outputted to the second optical beam splitter 509, the first transmitted beam T 'is outputted to the second optical beam splitter 509, reflected and transmitted to obtain a fifth reflected beam TR' and a fifth transmitted beam TT ', the first reflected beam R' is outputted to the second optical beam splitter 509, reflected and transmitted to obtain a third reflected beam RR 'and a third transmitted beam RT', the third transmitted beam RT 'and the fifth reflected beam TR' are coherent to the second output optical collimator 505 port and outputted, the fifth transmitted light beam TT 'and the third reflected light beam RR' are output coherently with the third output light collimator 506.
Similarly, the second optical signal is output from the second input optical collimator 403 to the first optical beam splitter 508, reflected and transmitted, and divided into a second transmitted beam T1 'and a second reflected beam R1' of equal energy. The second reflected beam R1 'is directly output to the second beam splitter 509, the second reflected beam R1' is output to the right-angle prism 510 and output to the second beam splitter 509 after being reflected twice, the second transmitted beam T1 'is output to the second beam splitter 509 to be reflected and transmitted, and a sixth reflected beam TR 1' and a sixth transmitted beam TT1 'are obtained, and the second reflected beam R1' is output to the second beam splitter 509 to be reflected and transmitted, and a fourth reflected beam RR1 'and a fourth transmitted beam RT 1' are obtained. The fourth transmitted beam RT1 'and the sixth reflected beam TR 1' are output coherent with the first optical output collimator 504 port, and the fourth reflected beam RR1 'and the sixth transmitted beam TT 1' are output coherent with the fourth output optical collimator 507 port.
In two embodiments of the present invention, an optical differential quadrature phase shift keying format demodulator comprises: a first input light collimator, a second input light collimator, a first beam splitter, a second beam splitter, a right angle prism, a first output light collimator, a second output light collimator, a third output light collimator, and a fourth output light collimator. The two time delay interferometers are formed by sharing the right-angle prism, the first beam splitter and the second beam splitter, so that the size is small, the structure is compact, and the production cost is reduced due to the use of the right-angle prism made of glass materials; the 90-degree phase difference between the two time delay interferometers is realized by polishing and thinning a quarter wavelength at any position of four reflecting areas of a first optical signal and a second optical signal which are respectively reflected twice in a diameter prism, a material with a higher thermal expansion coefficient is not required to be added into a demodulator, the temperature is adjusted by attaching a heating resistor, and the optical path difference is changed, so that the temperature stability is good.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. An optical differential quadrature phase shift keying demodulator, comprising: a first input light collimator, a second input light collimator, a first beam splitter, a second beam splitter, a right angle prism, a first output light collimator, a second output light collimator, a third output light collimator, and a fourth output light collimator; wherein,
the first input light collimator and the second input light collimator are respectively used for converting the received optical signals into collimated light and outputting the formed two optical signals to the first beam splitter;
the first beam splitter is used for respectively transmitting and reflecting the two received optical signals and outputting two formed reflected beams and two transmitted beams;
the right-angle prism is used for reflecting and outputting the received two paths of transmitted beams twice;
the second beam splitter is used for transmitting and reflecting the two received reflected beams, respectively outputting the two formed transmitted beams to the third output light collimator and the fourth output light collimator, and respectively outputting the two formed reflected beams to the first output light collimator and the second output light collimator; simultaneously transmitting and reflecting the two received transmitted light beams, respectively outputting the two formed transmitted light beams to a first output light collimator and a second output light collimator, and respectively outputting the two formed reflected light beams to a third output light collimator and a fourth output light collimator;
the first output light collimator, the second output light collimator, the third output light collimator and the fourth output light collimator are respectively used for converging the received light beams and then outputting the converged light beams;
the first input light collimator, the second input light collimator and the first beam splitter form a vertically placed first cuboid, and the first beam splitter is a triangular prism equally divided by diagonal lines in the vertically placed first cuboid;
the second beam splitter, the first output light collimator, the second output light collimator, the third output light collimator and the fourth output light collimator are combined into a second cuboid which is vertically placed on the first cuboid, the second beam splitter is an inverted triangular prism which is uniformly divided by diagonal lines in the vertically placed second cuboid, and the third output light collimator and the fourth output light collimator are embedded into the inverted triangular prism from the top surface of the inverted triangular prism along the vertically placed direction;
the side surfaces of the triangular prism and the side surfaces of the inverted triangular prism are respectively plated with a light splitting film layer with a light splitting ratio of 50: 50;
the plane of the light splitting film layer of the first light beam splitter is vertical to the plane of the light splitting film layer of the second light beam splitter, and the planes of the light splitting film layers of the first light beam splitter and the second light beam splitter are vertical to the same transmitted light incidence plane;
the first input light collimator, the second input light collimator, the first output light collimator, and the second output light collimator are arranged along a vertical direction;
and the side surface of the right-angle prism is superposed with the side surface of a cuboid block consisting of the first beam splitter and the second beam splitter along the vertical placement direction.
2. The optical differential quadrature phase shift keying demodulator of claim 1, further comprising:
and the coupler is used for equally dividing the received optical signal and respectively outputting the optical signal to the first input optical collimator and the second input optical collimator.
3. The optical differential quadrature phase shift keying demodulator of claim 2,
the first beam splitter and the second beam splitter have correspondingly equal size parameters, and the first beam splitter has equal size parameters;
the length of the side edge of the right-angle prism is equal to the width of the vertically placed first cuboid, and the length of the hypotenuse of the right-angle prism is equal to the sum of the height of the vertically placed first cuboid and the height of the vertically placed second cuboid.
4. The optical differential quadrature phase shift keying demodulator of claim 2,
the coupler is located on the left side of the first input light collimator and the second input light collimator, the second output light collimator, the first output light collimator, the second input light collimator and the first input light collimator are sequentially arranged in the vertical direction and located on the right side of a cuboid block formed by the first beam splitter and the second beam splitter, the axial directions of the first input light collimator, the second input light collimator, the first output light collimator and the second output light collimator are perpendicular to the cubic direction, the third output light collimator and the fourth output light collimator are sequentially arranged in the horizontal direction, and the axial directions of the third output light collimator and the fourth output light collimator are perpendicular to the top surface of the second beam splitter.
5. The optical differential quadrature phase shift keying demodulator of any one of claims 2 to 4,
said coupler, said first input light collimator, said first beam splitter, said second beam splitter, said right angle prism, said second output light collimator, said third output light collimator, form a time-lapse interferometer;
the coupler, the second input light collimator, the first beam splitter, the second beam splitter, the right angle prism, the first output light collimator, and the fourth output light collimator constitute another time-delay interferometer.
6. The optical differential quadrature phase shift keying demodulator of claim 5,
the right-angle prism reflects the first transmission beam and the second transmission beam twice to form four reflection areas, and any one of the four reflection areas is polished to be thinned by a quarter wavelength.
7. The optical differential quadrature phase shift keying demodulator of claim 6,
a first input light collimator for converting the first optical signal equally divided by the coupler into first collimated light and outputting to the first beam splitter;
a second input light collimator for converting the second optical signal equally divided by the coupler into second collimated light and outputting to the first beam splitter;
the first beam splitter is used for transmitting and reflecting the first collimated light and respectively outputting the obtained first reflected beam and the obtained first transmitted beam to the second beam splitter and the right-angle prism; simultaneously transmitting and reflecting the second collimated light, and respectively outputting the obtained second reflected light beam and the obtained second transmitted light beam to a second light beam splitter and a right-angle prism;
the right-angle prism is used for reflecting the first transmitted beam and the second transmitted beam twice respectively and outputting the reflected beams to the second beam splitter;
the second beam splitter is used for transmitting and reflecting the first reflected beam and respectively outputting the obtained third transmitted beam and the third reflected beam to the third output light collimator and the second output light collimator; transmitting and reflecting the second reflected light beam, and respectively outputting the obtained fourth transmitted light beam and the fourth reflected light beam to a fourth output light collimator and the first output light collimator; simultaneously transmitting and reflecting the received first transmitted light beam, and respectively outputting the obtained fifth transmitted light beam and the fifth reflected light beam to a second output light collimator and a third output light collimator; and transmitting and reflecting the received second transmitted light beam, and outputting the obtained sixth transmitted light beam and sixth reflected light beam to the first output light collimator and the fourth output light collimator respectively.
8. The optical differential quadrature phase shift keying demodulator of claim 7,
the fifth transmitted light beam and the third reflected light beam have a matched time delay difference with the speed of a signal to be demodulated;
the fifth reflected light beam and the third transmitted light beam have a matched time delay difference with the speed of a signal to be demodulated;
the sixth transmitted light beam and the fourth reflected light beam have a matched time delay difference with the speed of a signal to be demodulated;
and the sixth reflected light beam and the fourth transmitted light beam have a matched time delay difference with the speed of a signal to be demodulated.
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