Wave-packet shaping network able to programme based on light WDM technologyTechnical field
The present invention relates to the device in a kind of Microwave photonics field, specifically a kind of Wave-packet shaping network able to programme of the ultra broadband great dynamic range based on light WDM technology.
Background technology
Phased array antenna system is such as radar, and the fields such as communication system are all widely used, and one of them requisite part is exactly the Wave-packet shaping network of phase delay.In traditional automatically controlled phased array antenna, an electric phase shifter is set on each antenna element, in order to change the phase relation of signal between antenna element, thereby provide out of phase poor relevant microwave signal for phased array radar.Yet, traditional automatically controlled phased array radar is limited to " aperture effect " of phased array antenna (referring to Zhang Guangyi, Zhao Yujie, phased array technology. Beijing: Electronic Industry Press, 2006.12:390-392), it is the skew that signal frequency variation can cause beam position, thereby limited the bandwidth of radar, can only under the signal bandwidth of relative narrower, scan, limit the performance of its wide bandwidth angle scanning aspect, thereby restricted the application of phased array antenna in complex environment and high-performance field.This is all huge defect for will completing radar, radar imagery and the spread-spectrum signal radar that high-resolution measures.
The development learning a skill along with microwave photon and in the extensive use of field of radar, the restriction that optically controlled phased array antennas is offset aperture fill time effectively by employing true time delay line technique is (referring to I.Frigyes and A.Seeds, " Optically generated true-time delay in phased-array antennas; " Microwave Theory and Techniques, IEEE Transactions on, vol.43, pp.2378-2386,1995.).Use formation and the scanning of the optically controlled phased array antennas wave beam of optical controlled beam forming network realization, there is large instant bandwidth, without series of advantages such as wave beam stravismus effect, low-loss, small size, anti-electromagnetic interference, detection range are far away, become an important directions of phased array radar development.
The core of Optical Controlled Phased Array Antenna is to produce the Wave-packet shaping network structure that true time postpones.The true time delay scheme of the optically controlled phased array antennas of the outer main flow of Current Domestic comprises two kinds of chromatic dispersion structure and optical fiber true time delay-line structures.Wherein, the constituted mode of chromatic dispersion structure has again several different methods, such as: fiber grating is (referring to C.Fan, S.Huang, X.Gao, J.Zhou, W.Gu, and H.Zhang, " Compact high frequencytrue-time-delay beamformer using bidirectional reflectance of the fiber gratings, " Optical Fiber Technology, vol.19, pp.60-65, 2013.), high-dispersive is fine (referring to M.Y.Chen, " Hybrid photonic true-time delay modules for quasi-continuous steering of 2-Dphased-array antennas, " Journal of Lightwave Technology, vol.31, pp.910-917, 2013.) etc., the formation of optical fiber true time delay-line structure comprises again both direction: simple pass through structure that switches light switch changes optical fiber true time delay line length (referring to B.-M.Jung, D.-H.Kim, I.-P.Jeon, S.-J.Shin, and H.-J.Kim, " Optical true time-delay beamformer based on microwave photonics for phased array radar, " in20113rd International Asia-Pacific Conference on Synthetic Aperture Radar, APSAR2011, September26, 2011-September30, 2011, Seoul, Korea, Republic of, 2011, pp.824-827.) and the structure of wavelength division multiplexer and optical fiber true time delay line combination (referring to O.Raz, S.Barzilay, R.Rotman, and M.Tur, " Submicrosecond scan-angle switching photonic beamformer with flat RF response in the C and Xbands, " Journal of Lightwave Technology, vol.26, pp.2774-2781, 2008.).Adopt multichannel wavelength division multiplexed light delay technique can simplify greatly the structure of system, make system configuration compact.
Summary of the invention
The object of the present invention is to provide a multi-wavelength Wave-packet shaping network device, thereby produce a ultra broadband great dynamic range and programmable smooth time delay network.
Technical solution of the present invention is as follows:
A kind of Wave-packet shaping network able to programme of the ultra broadband great dynamic range based on light WDM technology, feature is that its formation comprises: first wave division multiplexer, Second Wave division multiplexer, electrooptic modulator, the one 1 * 2 optical switch, the 21 * 2 optical switch and the coupling assembling between multilevel delay unit and delay cell, this coupling assembling is four port coupling assemblings.
Described delay cell comprises circulator, assembly, wavelength division multiplexer, optical fiber true time delay line and faraday rotation mirror, 2 ports of described circulator are connected and realize after light wave demultiplexing through the wavelength division multiplexer described in described assembly connects, different passages are through having the optical fiber true time delay line of different retardations, and the end of each passage optical fiber true time delay line is connected with described faraday rotation mirror, after the multipath light signal of different wave length is multiplexing by described first wave division multiplexer, enter the light input end of described electrooptic modulator, the light output end of this electrooptic modulator is connected with 2 ports of the described the one 1 * 2 optical switch, 3 ports of the described the one 1 * 2 optical switch connect 1 port of the coupling assembling between first order delay cell and second level delay cell, 1 port of the one 1 * 2 optical switch is connected with 1 port of the circulator of first order delay cell, 3 ports of this circulator connect 2 ports of the coupling assembling between first order delay cell and second level delay cell, 3 ports of this coupling assembling connect 1 port of the circulator of second level delay cell, 3 ports of the optical switch of the 21 * 2 described in 3 ports of the circulator of afterbody delay cell connect, 1 port of the 21 * 2 optical switch connects 4 ports of previous stage coupling assembling, 2 ports of the 21 * 2 optical switch connect described Second Wave division multiplexer.
If the assembly optical patchcord of described delay cell, described coupling assembling is the link block of the dual input dual output that constitutes of optical switch and image intensifer.
If the assembly image intensifer of described delay cell, the optical switch that described coupling assembling is 2 * 2.
Described wavelength division multiplexer is dense wave division multiplexer (DWDM) or arrayed waveguide grating type Wavelength division multiplexer/demultiplexer (AWG).
1 * 2 described optical switch, 2 * 2 optical switches are that mems optical switch, electric light open the light or magneto-optic shutter.
Described electrooptic modulator is light intensity modulator or optical phase modulator, and described light intensity modulator is lithium niobate MZ structured light intensity modulator/or polymer MZ structured light intensity modulator or electroabsorption modulator.Described optical phase modulator is lithium niobate phase modulator or polymer phase-modulator.
Described optical fiber true time delay line is the monomode fiber with following specific length:
The optical fiber true time delay line that in first order delay cell, wavelength division multiplexer rear end connects has the channel spacing of Δ τ, the optical fiber true time delay line that in the delay cell of the second level, wavelength division multiplexer rear end connects has the channel spacing of 2 Δ τ, the rest may be inferred, and the optical fiber true time delay line that in K level delay cell, wavelength division multiplexer rear end connects has 2k-1the channel spacing of Δ τ.
Described image intensifer is erbium-doped fiber amplifier or semiconductor optical amplifier, is used for realizing the amplification of light signal, effectively suppresses the Insertion Loss of microwave signal, reduces the noise factor of system.
Described faraday rotation mirror is light wave reflection device, is used for realizing optical fiber true time delay line length and reduces by half.
Described circulator is low-loss optically passive device, in order to realize the directional transmissions of light wave.
The present invention has the following advantages:
1, the optical fiber true time delay line in the present invention is to complete online by high-precision cutting method, by improving method of measurement, can also continue to improve making precision, thereby reduce the interval of different interchannel optical fiber true time delay lines, realize less delay stepping.
2, the present invention is a kind of Wave-packet shaping network able to programme of the super bandwidth great dynamic range based on light WDM technology, utilize wavelength division multiplexer, electrooptic modulator, optical switch, image intensifer, circulator and faraday rotation mirror, and in conjunction with different length optical fiber true time delay line, can realize different delay steppings, thereby improve the scanning accuracy of multi-wavelength beam forming.
3, the present invention, is modulated at microwave signal on the light signal of different wave length by electrooptic modulator, utilizes optical fiber true time delay line, realizes different retardations, thereby realize the phase delay that microwave signal is different in full photosystem.In whole system, by the true time that adopts optical fiber true time delay line to realize light signal, postpone, so all can realize the function of optics phase shift for the microwave signal of any wave band, improved greatly the bandwidth of operation of system, i.e. the present invention has the feature of ultra broadband.
4, the present invention, has carried out light amplification for every one-level multi-wavelength delay unit, has effectively suppressed the Insertion Loss of microwave signal, has reduced the noise factor of system.Therefore by the topology of multi-wavelength delay unit, increase the progression of wavelength division multiplexer, can realize the adjustable of amount of delay on a large scale, i.e. the present invention has the feature of great dynamic range.
5, the present invention, can be for 1 * 2 in system, and 2 * 2 optical switch carries out control able to programme.By " ON " of optical switch different modes, " OFF " combination, selects different delay passages, realizes different retardations, i.e. the present invention has programmable feature.
Accompanying drawing explanation
Fig. 1 is the structural representation of an embodiment of Wave-packet shaping network able to programme that the present invention is based on the ultra broadband great dynamic range of light WDM technology.
Fig. 2 be the present invention is based on the Wave-packet shaping network able to programme of the ultra broadband great dynamic range of light WDM technology can topological structure schematic diagram.
Fig. 3 (a) is the port explanation of 1 * 2 optical switch, and Fig. 2 (b) is the port explanation of 2 * 2 optical switches.
Fig. 4 is that the link block of the dual input dual output that constitutes of the optical switch of two 1 * 2 and image intensifer illustrates.
Fig. 5 is the port explanation of circulator, and light wave can only be transmitted to 2 ports from 1 port in circulator, from 2 ports, is transmitted to 3 ports, otherwise cannot.
Fig. 6 is the phase delay that produces under different delayed time state of a certain passage of optical wavelength-division multiplex in specific implementation process of the present invention and the experimental results between frequency.
Embodiment
Below in conjunction with accompanying drawing, provide a specific embodiment of the present invention.The present embodiment be take technical scheme of the present invention and is implemented as prerequisite, provided detailed execution mode and process, but protection scope of the present invention should not be limited to following embodiment.
Fig. 1 is the structural representation of Wave-packet shaping network embodiment able to programme that the present invention is based on the ultra broadband great dynamic range of light WDM technology.As seen from the figure, the Wave-packet shaping network able to programme of the ultra broadband great dynamic range of the present embodiment based on light WDM technology, its formation comprises: the optical switch of the optical switch the 8, the 22 * 2 of the optical switch the 18, the one 2 * 2 of firstwave division multiplexer 1, Second Wave division multiplexer 19,electrooptic modulator 2, the one 1 * 2optical switch 3, the 21 * 2 13, three grades of delay cells 23.First order delay cell consists of wavelength division multiplexer 5,image intensifer 20,circulator 4, optical fiber truetime delay line 6, faraday rotation mirror 7; Second level delay cell consists ofwavelength division multiplexer 10, image intensifer 21, circulator 9, optical fiber true time delay line 11,faraday rotation mirror 12; Third level delay cell consists of wavelength division multiplexer 15, image intensifer 22, circulator 14, optical fiber true time delay line 16, faraday rotation mirror 17.
The annexation of above-mentioned component is as follows:
The multiplexing laggard light input end that enterselectrooptic modulator 2 ofwavelength division multiplexer 1 described in the optical signals of different wave length, the light output end of thiselectrooptic modulator 2 is connected with 2 ports of 1 * 2optical switch 3,1 port of 1 * 2optical switch 3 is connected with 1 port ofcirculator 4, and 3 ports of 1 * 2optical switch 3 are connected with a port of the input direction of 2 * 2optical switch 8; Wherein the light wave of each wavelength is multiplexing throughwavelength division multiplexer 1, the interface of different passages of process and the microwave input port of electrooptic modulator as the input of this device;
2 ports of describedcirculator 4 are connected withimage intensifer 20, and then are connected and realize after light wave demultiplexing with wavelength division multiplexer 5, and different passages are through the optical fiber truetime delay line 6 of different retardations, and then each channel end is connected with faraday rotation mirror 7; 3 ports ofcirculator 4 are connected with the another port of the input direction of 2 * 2optical switch 8;
One port of output direction and 1 port of circulator 9 of described 2 * 2optical switch 8 are connected, and another port is connected with a port of 2 * 2 optical switch 13 input directions; 2 ports of circulator 9 are connected with image intensifer 21, and then are connected and realize after light wave demultiplexing withwavelength division multiplexer 10, and different passages are through the optical fiber true time delay line 11 of different retardations, and then each channel end is connected withfaraday rotation mirror 12; 3 ports of circulator 9 are connected with the another port of 2 * 2 optical switch 13 input directions;
One port of described 2 * 2 optical switch 13 output directions is connected with 1 port of circulator 14, and another port is connected with 1 port of 1 * 2 optical switch 18; After 2 ports of circulator 14 are connected with image intensifer 22, then are connected and realize after light wave demultiplexing with wavelength division multiplexer 15, different passages are through the optical fiber true time delay line 16 of different retardations, and then each channel end is connected with faraday rotation mirror 17; 3 ports of circulator 14 are connected with 3 ports of 1 * 2 optical switch 18;
2 ports of described 1 * 2 optical switch 18 are connected with wavelength division multiplexer 19, realize different passages after light wave demultiplexing as the output of this device.
Describedwavelength division multiplexer 1,5,10,15,19 is dense wave division multiplexer (DWDM).The light of described 1 * 2optical switch 3,18,2 * 2 opens 8,13rd, mems optical switch, and wherein 1 * 2 optical switch is replaced using by 2 * 2 optical switch.Describedelectrooptic modulator 2 is lithium niobate MZ structured light intensity modulator.Described image intensifer is semiconductor optical amplifier (SOA).Described optical fiber truetime delay line 6,11,16 for having the monomode fiber of specific length after precision cutting, the optical fiber truetime delay line 6 that wavelength division multiplexer 5 rear ends connect has the channel spacing of Δ τ, the optical fiber true time delay line 11 thatwavelength division multiplexer 10 rear ends connect has the channel spacing of 2 Δ τ, and the optical fiber true time delay line that wavelength division multiplexer 15 rear ends connect has the channel spacing of 4 Δ τ.
Table 1 is four channel spacing test datas wherein in specific implementation process of the present invention.
Table 1.
Operation principle of the present invention is as follows:
First, the laser of a plurality of wavelength after DWDM1 is multiplexing as carrier signal, microwave signal is modulated in carrier signal through the RF input port ofelectrooptic modulator 2, then after the programmable optical fiber true time delay network forming by DWDM, circulator, image intensifer, optical switch, optical fiber true time delay line and faraday rotation mirror, pass through DWDM19 demultiplexing out, so just form the carrier signal after relevant modulated of multichannel, can be sent to photodetector and the aerial array of rear end, thereby complete the beam scanning in space.
Wherein, in whole multi-wavelength Wave-packet shaping network device, most crucial part is exactly optical fiber true time delay network.In the elementary cell of this delay network, the port number of DWDM equates with the antenna submatrix number that needs phase shift to control.Each passage of DWDM adopts the delay line of reflection mode, at channel delay line tail end, utilizes faraday rotation mirror as speculum.DWDM interchannel fiber lengths distributes according to arithmetic progression.In order to realize larger retardation, this delay cell is carried out to cascade, and introduce optical switch and control.
In delay cell not at the same level, between the wavelength of wavelength division multiplexing, retardation adopts progression to distribute.Such as, first order DWDM interchannel (between wavelength) retardation distributes according to arithmetic progression, interchannel length difference is arranged to Δ L, second level DWDM is different, and channel delay amount still distributes according to arithmetic progression, but interchannel delay amount is arranged to 2 * Δ L, between 3rd level DWDM wavelength, retardation is arranged to 4 * Δ L, and between K level DWDM wavelength, retardation is arranged to 2k-1* Δ L.In System Implementation process, we arrange the 5mm, second level, first order DWDM5 interchannel interval DWDM10 interchannel interval 10mm, and third level DWDM15 interchannel interval 20mm verifies.Then we are together in series elementary cell by circulator and optical switch, form continuous, quick adjustable multi-wavelength beam forming time delay network." ON " opening the light by light, the delay passage that " OFF " gating is different, the carrier signal of final different wave length has just formed different phase delay.