CN102158286B - Reflective Differential Phase Shift Keying Coherent Receiver - Google Patents
Reflective Differential Phase Shift Keying Coherent Receiver Download PDFInfo
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- CN102158286B CN102158286B CN201110024575.3A CN201110024575A CN102158286B CN 102158286 B CN102158286 B CN 102158286B CN 201110024575 A CN201110024575 A CN 201110024575A CN 102158286 B CN102158286 B CN 102158286B
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Abstract
A differential phase shift keying coherent receiver for free space optical communication is composed of a reflection type differential optical circuit, a 2 x 4 optical bridge, a photoelectric detector, a two-channel balanced receiving circuit and a phase-locked circuit. The optical signal receiving circuit is used for receiving optical signals in the space laser communication receiver and outputting data signals through the data processing circuit. After the balanced received signals of the two channels are multiplied, the multiplied signals are output to control the phase precision controller through the phase locking circuit. The invention can realize light balance receiving; the phase-locked circuit is used for controlling the optical path precision adjustment in real time, so that the optical path difference can be kept stable, and the system precision is ensured.
Description
Technical field
The present invention relates to laser space communication, be a kind of differential phase keying (DPSK) for free space laser communication (being designated hereinafter simply as DPSK) coherent signal optical receiver, formed by reflection type differential light circuit, 2 × 4 optical bridging devices, photodetector, two balance receive paths, phase lock circuitries.Light signal for laser space communication receiver receives, treated circuit, output signal (coding).
Background technology
Formerly technology [1] (2 × 490 ° of Free Space Optics bridgers of phase compensation polarization spectro, Acta Optica, Vol.29,3291～3294,2009) the free space bridger described in is by after flashlight and local oscillator light compositing, output four bundles, wherein form homophase passage and orthogonal channel between two, and balance receives.Between homophase passage and orthogonal channel, differ 90 degree, produce phase-locked required error signal.In the present invention, need the flashlight self of flashlight and time delay synthetic, realize balance reception and phase-locked, need to improve.
Formerly technology [2] (High-data-rate systems for space applications, Proc.SPIE, Vol.2381,38,1995) in the star ground laser communication described in, adopt DPSK modulation, receiver adopts fiber amplifier and the demodulation of optical-fiber type Mach-Zehnder interferometers, and balance receives, the high 3dB of remolding sensitivity on-off keying (OOK) modulation direct detection method.But the corrugated Quality Down under atmospheric perturbation, optical coupling efficiency reduces, and has a strong impact on sensitivity, and the ability of this modulation system disturbance rejection of DPSK is not fully utilized.
Formerly technology [3] (Adaptive optics and ESA ' s optical ground station, Proc.SPIE, Vol.7464,746406,2009) the DPSK demodulation described in adopts Mach-Zehnder interferometers or the Michelson's interferometer of free-space structure, the control precision that should guarantee the difference of two brachiums in work is far superior to quarter-wave, is about 0.2 micron.But in structure, lack accurate device and the phase-locked loop adjusted, cannot guarantee system accuracy, can not adjust in real time.Do not have balance to receive simultaneously, cannot remove DC component, sensitivity is lower.
Summary of the invention
The technical problem to be solved in the present invention is to overcome above-mentioned prior art difficulty, and a kind of reflective differential phase keying (DPSK) coherent receiver is provided, and receives to realize photo-equilibrium; Utilize phase lock circuitry to control in real time the accurate adjustment of light path, keep optical path difference stable, guarantee system accuracy.
Technical solution of the present invention is as follows.
A kind of reflective differential phase keying (DPSK) coherent receiver, feature is that its formation comprises opticator, photodetector part and electronics part:
Opticator comprises reflection type differential light circuit and 2 × 490 ° of Free Space Optics bridgers, electronics part comprises homophase detection channels, orthogonal detection channels, phase lock circuitry and data processing circuit, and described photodetector part comprises four photodetectors;
Described reflection type differential light circuit is made up of the first polarization beam apparatus, the first quarter-wave plate, the second quarter-wave plate, first lens, long focus lens, the first speculum, the second speculum, the second polarization beam apparatus (6) the 3rd speculum and the 4th speculum, and its position relationship is: be the first quarter-wave plate, lens and the first speculum successively in the transmission direction of the first polarization beam apparatus, the second quarter-wave plate, long focus lens, accurate position phase control device and the second speculum successively in the anti-transmission direction of the first polarization beam apparatus, after the reverberation of the first described speculum enters the first described polarization beam apparatus, through boundary reflection, being the second polarization beam apparatus and the 4th speculum successively in this reverberation direction, is the 3rd speculum in the reverberation direction of the second polarization beam apparatus, light through the 3rd described speculum and the reflection of the 4th speculum enters 2 × 490 ° of described Free Space Optics bridgers simultaneously, four outputs of these 2 × 490 ° of Free Space Optics bridgers arrange respectively the first photodetector, the second photodetector, the 3rd photodetector, the 4th photodetector, after the first described photodetector and the second photodetector, it is orthogonal balanced circuit, after the 3rd described photodetector and the 4th photodetector, it is homophase balancing circuitry, the output of described homophase balancing circuitry is connected with the input of data processing circuit and multiplier circuit simultaneously, the output of described orthogonal balanced circuit is connected with the input of described multiplier circuit, the output of this multiplier circuit is connected with the control end of described accurate position phase control device through described phase lock circuitry.
Light beam equals the time interval of modulating data 1 bit through the time difference of the two-way light of described reflection type differential light circuit output, through the 3rd photodetector with the 4th photodetector is surveyed and receive signal by the balance of described homophase balancing circuitry processing is restituted signal.
The focal length of described long focus lens is f1; The focal length of another lens is f2, and it is that the spacing of the second described speculum and described long focus lens is that the spacing of focal distance f 1, the first speculum and lens is focal distance f 2, and meets relational expression at the interface of the first polarization beam apparatus that the position of light entrance pupil and emergent pupil overlaps:
In formula: c is the light velocity, G is message transmission rate.
Described the first speculum and pupil imaging lens are divided into guide rail, and mobile accuracy is 100 microns, form the light path module of mating with message transmission rate G.
Described make multiple light path modules with different light paths from the light path module of message transmission rate G coupling, change light path module according to the difference of message transmission rate, to realize and the mating of transmission rate G.
Described accurate position phase control device is the optical element of printing opacity, is electrooptic modulation crystal or two collimating optics glass plate.
Technique effect of the present invention is as follows:
The present invention adopts non-optical fiber free-space structure, for the demodulation of laser space communication dpsk signal.Adopt polarizer and pupil imaging lens composition reflecting light loop, together with 2 × 490 ° of Free Space Optics bridgers, can realize photo-equilibrium and receive; Utilize phase lock circuitry to control in real time the accurate adjustment of light path, can keep optical path difference stable, guarantee system accuracy.
Accompanying drawing explanation
Fig. 1 is main structure schematic diagram of the present invention
Fig. 2 is the concrete structure figure implementing
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described, but should not limit the scope of the invention with this.
As shown in Figure 1, the reflective differential phase keying (DPSK) coherent receiver of the present invention, forms and comprises opticator, photodetector part and electronics part:
Opticator comprises reflection type differential light circuit and 2 × 490 ° of Free Space Optics bridgers 27, electronics part comprises homophase detection channels, orthogonal detection channels, phase lock circuitry (23) and data processing circuit (24) etc., and described photodetector part comprises four photodetectors.
Reflection type differential light circuit, this loop is made up of the first polarization beam apparatus 1, the first quarter-wave plate 2, the second quarter-wave plate 3, lens 20, long focus lens 21, the first speculum 5, the second speculum 4, the second polarization beam apparatus 6, the 3rd speculum 7 and the 4th speculum 8, and its position relationship is: be the first quarter-wave plate 2, lens 20 and the first speculum 5 successively in the transmission direction of the first polarization beam apparatus 1, the second quarter-wave plate 3, long focus lens 21, accurate position phase control device 22 and the second speculum 4 successively in the anti-transmission direction of the first polarization beam apparatus 1, after entering the first described polarization beam apparatus 1, the reverberation of the second described speculum 5 reflects through interface 1a, being the second polarization beam apparatus 6 and the 4th speculum 8 successively in this reverberation direction, is the 3rd speculums 7 in the reverberation direction of the second polarization beam apparatus 6, the light reflecting through the 3rd described speculum 7 and the 4th speculum 8 enters 2 × 490 ° of described Free Space Optics bridgers 27 simultaneously, four outputs of these 2 × 490 ° of Free Space Optics bridgers 27 arrange respectively the first photodetector 16, the second photodetector 17, the 3rd photodetector 18, the 4th photodetector 19, after the first described photodetector 16 and the second photodetector 17, it is orthogonal balanced circuit 26, after the 3rd described photodetector 18 and the 4th photodetector 19, it is homophase balancing circuitry 25, the output of described orthogonal balanced circuit 26 is connected with the input of multiplier circuit 28 with data processing circuit 24 simultaneously, the output of described homophase balancing circuitry 25 is connected with the input of described multiplier circuit (28), the output of this multiplier circuit (28) is connected with the control end of described accurate position phase control device 22 through described phase lock circuitry 23.
Wherein photodetector, electronics part are matured product or technology, can buy or entrust development.
Suppose that receiving light is circularly polarized light (other polarization state if, need to be converted to circularly polarized light).When through polarization beam apparatus, reverberation is orthogonal polarized light, and transmitted light is horizontal polarization light.
First input signal light enters reflection type differential light circuit, through the first polarization beam apparatus 1, at this 1a place, polarization beam apparatus interface, the transmission of horizontal polarization light and orthogonal polarized light reflection, respectively after the first quarter-wave plate the 2 or the 21 quarter-wave plate 3, after lens 20 or long focus lens 21, the first speculums 4 or the second speculum 5 reflections, former road turns back to the first polarization beam apparatus 1.Because there is quarter-wave plate, thus original horizontal polarization and vertical polarization exchange, transmission and reflection conversion, vertical with input signal light direction through the direction of the two-beam of the first polarization beam apparatus 1.Arrive after the second polarization beam apparatus 6, be divided into two bundles, after being reflected by the 3rd speculum 7 or the 4th speculum 8, enter 2 × 490 ° of optical bridging devices 27, survey and be converted to the signal of telecommunication via the first photodetector 16, the second photodetector 17, the 3rd photodetector 18, the 4th photodetector 19, a part for the same receiving circuit 26 that balances each other is through data processing circuit 24 output signals; The signal of another part and orthogonal balanced receiving circuit 25 multiplies each other after multiplier circuit 28, after processing, as the control signal of accurate position phase control device 22, keeps light path stable via phase lock circuitry 23.
When light beam is through reflection type differential light circuit, the two-way light (will incide 2 × 490 ° of optical bridging devices) of output, their time difference equals the time interval of modulating data 1 bit, and balance receives signal and is restituted signal.
As shown in Figure 1, the long focus lens 21 of pupil imaging, focal length is f1; Another lens 20, focal length is f2.Light entrance pupil and exit pupil position overlap as the interface 1a at the first polarization beam apparatus 1.The second speculum 5 is focal distance f 2 with the spacing that the spacing of described long focus lens 21 is focal distance f 1, the first speculum 4 and lens 20, meets relational expression:
Speculum 5 and pupil imaging lens 20, divide into guide rail, and mobile accuracy is 100 microns, is the light path module of mating with message transmission rate G.Can make multiple light path modules, change according to the difference of message transmission rate.
The optical element that described accurate position phase control device 22 is printing opacity, one is electrooptic modulation crystal, changes bias voltage, by the change in optical path length of crystal, precision is higher than quarter-wave.Another kind is the two parallel flats of optical glass, by precision rotation angle, changes light by dull and stereotyped light path, and precision is far above quarter-wave.
The concrete structure of an embodiment of reflective differential phase keying (DPSK) coherent receiver of the present invention as shown in Figure 2, circularly polarized flashlight sees through the first polarization beam apparatus 1, the first quarter-wave plate 2, lens 20, after the first speculum 5 reflections, scioptics 20 again, the first quarter-wave plate 2, after the first polarization beam apparatus 1 reflection, reflect through the second polarization beam apparatus 6, the 3rd speculum 7, the 3rd quarter-wave plate 10, the 3rd polarization beam apparatus 11, the 1/2nd wave plate 12, the 4th polarization beam apparatus 15 forms orthogonal channel, survey and be converted to the signal of telecommunication through the first photodetector 16 and the second photodetector 17, this first photodetector 16 and the second photodetector 17 are generally PIN photodiode, the signal of telecommunication by the first photodetector 16 and the second photodetector 17 subtracts each other, processed by orthogonal balanced circuit 25.Circular polarization flashlight is in the reflecting surface 1a of the first polarization beam apparatus 1 reflection, through the second quarter-wave plate 3, long focus lens 21, accurate position phase control device 22, reflect again by accurate position phase control device 22 through the second speculum 4, long focus lens 21, the second quarter-wave plate 3, after the first polarization beam apparatus 1 transmission, through the second polarization beam apparatus 6 transmissions, through the 4th speculum 8, the 1/1st wave plate 9, the 3rd polarization beam apparatus 11, the 1/3rd wave plate 13, the 5th polarization beam apparatus 14 forms homophase passage, the signal of telecommunication is surveyed and be converted to the 3rd described photodetector the 18 and the 43 photodetector 19, the 3rd photodetector the 18 and the 43 photodetector 19 is generally PIN photodiode, the signal of telecommunication by the 3rd photodetector 18 and the four or three photodetector 19 subtracts each other, processed by homophase balancing circuitry 26, through the homophase balancing circuitry signal of telecommunication after treatment, part output is exported data through data processing circuit 24, another part and orthogonal balanced treatment circuit 25 signal of telecommunication after treatment multiplies each other through multiplier circuit 28, processed by phase lock circuitry 23, as the control signal of accurate position phase adjuster 22, the optical path difference of steady reflection light circuit.
As shown in Figure 2.The entrance pupil of lens 20 and 21 and exit pupil position overlap as 1a, and the object distance of entrance pupil is 1 times of focal length.
The optical axis direction of the 1/1st wave plate 9, the 1/2nd wave plate 12 and the 1/3rd wave plate 13 becomes 22.5 degree with incident light polarization direction.Polarised light is after 1/2nd wave plates, and polarization direction rotation 45 is spent.Then pass through polarization beam apparatus, orthogonal polarized light reflection, the transmission of horizontal polarization light.
Experiment and data analysis show, the present invention adopts non-optical fiber free-space structure, for the demodulation of laser space communication dpsk signal.Adopt polarizer and pupil imaging lens composition reflecting light loop, together with 2 × 490 ° of Free Space Optics bridgers, can realize photo-equilibrium and receive; Utilize phase lock circuitry to control in real time the accurate adjustment of light path, can keep optical path difference stable, guarantee system accuracy.
Claims (6)
1. a reflective differential phase keying (DPSK) coherent receiver, is characterised in that its formation comprises opticator, photodetector part and electronics part:
Opticator comprises reflection type differential light circuit and 2 × 4 90 ° Free Space Optics bridger, electronics part comprises homophase detection channels, orthogonal detection channels, phase lock circuitry (23) and data processing circuit, and described photodetector part comprises four photodetectors;
Described reflection type differential light circuit is by the first polarization beam apparatus (1), the first quarter-wave plate (2), the second quarter-wave plate (3), first lens (20), long focus lens (21), the first speculum (5), the second speculum (4), the second polarization beam apparatus (6), the 3rd speculum (7) and the 4th speculum (8) form, its position relationship is: be the first quarter-wave plate (2) successively in the transmission direction of the first polarization beam apparatus (1), first lens (20) and the first speculum (5), the second quarter-wave plate (3), long focus lens (21), accurate phase control device (22) and the second speculum (4) successively in the anti-transmission direction of the first polarization beam apparatus (1), entering described the first polarization beam apparatus (1) at the reverberation of described the first speculum (5) reflects by interface (1a), being the second polarization beam apparatus (6) and the 4th speculum (8) successively in this reverberation direction, is the 3rd speculum (7) in the reverberation direction of the second polarization beam apparatus (6), light through the 3rd described speculum (7) and the reflection of the 4th speculum (8) enters described 2 × 4 90 ° of Free Space Optics bridgers (27) simultaneously, four outputs of these 2 × 490 ° of Free Space Optics bridgers (27) arrange respectively the first photodetector (16), the second photodetector (17), the 3rd photodetector (18), the 4th photodetector (19), orthogonal balanced circuit (25) afterwards at described the first photodetector (16) and the second photodetector (17), homophase balancing circuitry (26) afterwards at the 3rd described photodetector (18) and the 4th photodetector (19), the output of described homophase balancing circuitry (26) is connected with the input of multiplier circuit (28) with data processing circuit (24) simultaneously, the output of described orthogonal balanced circuit (25) is connected with the input of described multiplier circuit (28), the output of this multiplier circuit (28) is connected with the control end of described accurate position phase control device (22) through described phase lock circuitry (23).
2. reflective differential phase keying (DPSK) coherent receiver according to claim 1, it is characterized in that light beam equals the time interval of modulating data 1 bit through the time difference of the two-way light of described reflection type differential light circuit output, through the 3rd photodetector (18) with the 4th photodetector (19) is surveyed and the balance reception signal processed by described homophase balancing circuitry (26) is restituted signal.
3. reflective differential phase keying (DPSK) coherent receiver according to claim 1, is characterized in that the focal length of described long focus lens (21) is f1; The focal length of first lens (20) is f2, it is at the interface of the first polarization beam apparatus (1) (1a) that the position of light entrance pupil and emergent pupil overlaps, described the second speculum (4) is focal distance f 1 with the spacing of described long focus lens (21), the first speculum (5) is focal distance f 2 with the spacing of first lens (20), and meets relational expression:
In formula: c is the light velocity, G is message transmission rate.
4. reflective differential phase keying (DPSK) coherent receiver according to claim 3, the first speculum (5) and first lens (20) described in it is characterized in that are divided into guide rail, mobile accuracy is 100 microns, forms the light path module of mating with message transmission rate G.
5. reflective differential phase keying (DPSK) coherent receiver according to claim 4, the light path module from message transmission rate G coupling described in it is characterized in that is made multiple light path modules with different light paths, change light path module according to the difference of message transmission rate, to realize and the mating of transmission rate G.
6. reflective differential phase keying (DPSK) coherent receiver according to claim 1, is characterized in that described accurate position phase control device (22) is the optical element of printing opacity, is electrooptic modulation crystal or two collimating optics glass plate.
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| CN102594456B (en) * | 2012-03-29 | 2014-10-15 | 中国科学院上海光学精密机械研究所 | Self-phase differential interference optical signal receiving device |
| CN102624447B (en) * | 2012-03-29 | 2014-10-01 | 中国科学院上海光学精密机械研究所 | Double-optical-path real-time control differential interference receiving device |
| CN111780853A (en) * | 2020-07-10 | 2020-10-16 | 上海交通大学 | Optical fiber hydrophone array high-frequency response detection method based on orthogonal frequency division multiplexing |
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| CN102098095A (en) * | 2011-01-21 | 2011-06-15 | 中国科学院上海光学精密机械研究所 | Transmission type differential phase shift keying coherent receiver |
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| CN102098095A (en) * | 2011-01-21 | 2011-06-15 | 中国科学院上海光学精密机械研究所 | Transmission type differential phase shift keying coherent receiver |
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| 冯勇等.差分相移键控信号的数字相干光检测与色散补偿研究与实现.《中国激光》.2010,第37卷(第2期),471-475. |
| 差分相移键控信号的数字相干光检测与色散补偿研究与实现;冯勇等;《中国激光》;20100228;第37卷(第2期);471-475 * |
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