CN207096498U - A kind of high-precision N bit adjustable light delays - Google Patents

Abstract

The utility model provides a kind of high-precision N bit adjustable light delays, is mainly made up of optical switch chip, collimator lens array, free space time delay module, input-output optical fiber tail optical fiber, base.Wherein optical switch chip is integrated for the array of multiple optical switch elements, and free space time delay module realizes the integration of multistage delay unit, and both efficient couplings are realized by lens array, finally achievable ps level step-lengths, 10 more than bit adjustable light delay.The utility model have the advantages that delay precision it is high, with roomy, small volume, it is in light weight, be easy to technique and realize, be especially suitable for the application in the field such as Optical Controlled Phased Array Antenna system, particularly airborne, spaceborne radar.

Description

A kind of high-precision N-bit adjustable light delays

Technical field

Photoelectric device technical field is the utility model is related to, more particularly to a kind of high-precision tunable optical delayer.

Background technology

In phased array radar system, the phase shifter configuration of traditional electrical domain phased array antenna is relevant with microwave signal frequency, This makes its instant bandwidth very narrow.To realize the big instant bandwidth of phased-array radar, true delay (True Time Delay) should be used Technology replaces electrical domain phase shifter.Traditional TTD is made up of waveguide or coaxial cable, this to microwave signal direct delay Method is limited by electrical circuit density, and the time-delay network constructed is bulky and heavy, loss of signal is high, no matter in performance also It is not possess practicality in engineering.Microwave signal is modulated on light, timing circuit is done with fiber waveguide, be i.e. optics is really delayed skill Art (OTTD), device have small volume, it is in light weight, with it is roomy, transmission is stable, the advantage without mutual radiation interference, be microwave light The important research field that son is learned.

To make antenna scanning direction adjustable, the necessary delay length of optical time delay unit is adjustable；And it is to ensure antenna scan angle High-resolution, the tuning step-length of optical time delay unit should be sufficiently small.To meet high band radar application, it is delayed for step-by-step movement tunable optical Device, delay stepping need to typically reach ps magnitudes, now it is believed that this is the adjustable light delay of a kind of " quasi-continuous ".

The implementation of adjustable light delay has a variety of at present, mainly include " photoswitch+delay line ", optical resonator, Chirp grating, photonic crystal etc..These schemes of optical resonator, chirp grating, photonic crystal can realize the continuous of light delay Tuning, but all belong to resonance structure, delay-bandwidth product of the limited performance that optical signal postpones in resonance structure inherently, they Bandwidth it is all narrow, it is impossible to meet the application demand of wideband radar." photoswitch+delay line " scheme can realize big bandwidth, But belong to step-by-step movement tunable optical delay technique, in order to meet high band radar application, it must delay stepsize it is sufficiently small, delay essence Spend sufficiently high.

" photoswitch+fiber delay time " scheme is classical step-by-step movement tunable optical delay technique, but limited by optical fiber machining accuracy To make, delay precision can only accomplish 0.01ns or so, be suitable only for the low-frequency range application such as S-band, and by the volume of discrete optical fibre device Weight limits, and devices difficult realizes integration and miniaturization, limits its application in the field such as airborne/spaceborne.

A kind of emerging technology is the tunable optical delay technique integrated on " photoswitch+fiber waveguide delay " piece, its delay precision Below 0.1ps is can reach, the delay precision requirement of high band radar application can be met, but it also exists in technique realization Problem.According to the small size waveguide fabrication of submicron order, there is the coupling efficiency of larger waveguide optical transmission loss, chip and optical fiber The problems such as relatively low, delay path accurately controls difficult and chip performance high to process sensitivity；According to micron-sized big chi Very little waveguide, the bending radius of waveguide is then larger, and achievable delayer bit numbers are less, it is impossible to meet application demand.In addition, piece Upper integrated more bit optical time delay units, due to the temperature dependency of Refractive Index of Material, Time delay variation caused by temperature change holds very much It is easily suitable with delay stepping even beyond delay stepping, thus device must have temperature control measures.In a word, integrated at present on piece " photoswitch+fiber waveguide delay " tunable optical delay technique is from practical also in the presence of more remote.

The content of the invention

The purpose of this utility model proposes a kind of high-accuracy light-adjustable delayer aiming at the deficiencies in the prior art, it Delay tune step-length up to 1ps, delay precision up to 0.1ps, while have with roomy, small volume, tuned speed is fast, is easy to The advantages that technique is realized, it disclosure satisfy that the application demand of Optically controlled microwave wideband radar.

Technical scheme is as follows disclosed in the utility model：

Using binary system " photoswitch+light delay " topological structure, device mainly by optical switch chip, collimator lens array, Free space time delay module, input-output optical fiber tail optical fiber, base composition.For N-bit adjustable light delays, free space prolongs When module need to construct N number of free space delay unit, delay units at different levels include 2 light delay paths, 2 light delay paths Optical path difference be to form the tunable optical delay length of this grade of light delay unit, the optical path difference of N number of free space delay unit meets 2⁰Δ L、2¹ΔL……2^N-1Δ L mathematical relationships, wherein Δ L represent tunable optical delay stepsize, and wherein N is positive integer.The N- Bit adjustable light delays carry out the selection of light delay path and switching by the optical switch element in optical switch chip, and then realize light Amount of delay it is tunable.Optical signals optical fiber inputs, and through carrying out delay path selection during the 1st optical switch element, selection enters Some delay path of 1st grade of delay unit, then the 2nd grade of delay path is selected through the 2nd optical switch element, the like, directly To N level delay paths are passed through, output end then is switched to by the N+1 optical switch element, optical signal is after delay from light Fibre output.

In the N-bit adjustable light delays, optical switch chip need to include N+1 optical switch element, N+1 photoswitch list Member from top to bottom laid out in parallel, wherein be coupled with input optical fibre be connected for the 1st optical switch element, with output optical fibre phase coupling Close connection for the N+1 optical switch element, the 1st optical switch element is 2 × 2 or 1 × 2 photoswitch, the N+1 Individual optical switch element is 2 × 2 or 2 × 1 photoswitches, and remaining N-1 optical switch element is 2 × 2 photoswitches.2 × 2 photoswitches Including 2 inputs and 2 output ends, respectively upper road input, lower road input, upper road output end, lower road output end；1 × 2 photoswitches include 1 input and 2 output ends, wherein 2 output ends are respectively upper road output end, lower road output end；2 × 1 photoswitch includes 2 inputs and 1 output end, wherein 2 inputs are respectively upper road input, lower road input, institute Shu Shang roads refer to close to the port of upside in 2 inputs or output end, and lower road refers in 2 inputs or output end close to downside Port.

Described photoswitch can utilize electrooptic effect, thermo-optic effect, plasma dispersion effect etc. to realize "ON", "Off" shape State controls, and can be based on silicon based SOI (Silicon On Insulator) material, organic polymer material etc..

To increase return loss, horizontal or vertical tiltedly polishing can be carried out to optical switch chip input/output Waveguide end face Processing, input/output fiber waveguide and chip normal line of butt end can be also made when chip designs into certain angle of inclination.

2 light timing circuits of the i-stage tunable optical delay unit of the adjustable light delay, its loop configuration mode be, Some output end of optical signal through i-th of optical switch element in one of light timing circuit exports, by Lens Coupling extremely Free space, light path reflexed is realized by the speculum of free space optical time delay module, then pass through Lens Coupling to i+1 light Some input of switch element, another output end of optical signal from i-th of photoswitch in another light timing circuit are defeated Go out, inputted by being coupled after light path reflexed in free space optical time delay module to another input of i+1 photoswitch, its Middle i is the positive integer no more than N.Described free space optical delay is made up of two parts light time delay module, is respectively placed in light and is opened The both sides of chip are closed, delay units at different levels are interleave in two parts time delay module.The smooth time delay module is by a series of reflections Mirror is formed with backing material, and tunable optical delay lengths at different levels are realized by the design of rows of mirrors cloth.Each delay unit is by two Delay path forms, and each delay path realizes that light path is turned back by two speculums, so as to be sent into next stage photoswitch.By right Reflector position is designed to realize that delay length designs.All speculums can be bonded by high-precision paster and glue bond technique In the time delay module of being integrally formed on the substrate with position groove.

Described optical switch chip light input/output waveguide and free space optical time delay module, both pass through lens array Coupled.

The parts such as the optical switch chip, free space optical time delay module, lens array, input/output optical fiber pigtail, lead to Described base mechanical structure is crossed to realize that Best Coupling to each other and relative position are fixed.

Described lens array uses equidistant Lens Design, and its spacing is equal between the minimum of photoswitch input/output terminal Away from.All focal lengths of lens of lens array can be designed as identical, may be designed in the lens array of non-homogeneous focal length, so that The coupling efficiency of each lens more matches with corresponding light path, and this depends on the balance of coupling efficiency and process complexity.

Described input-output optical fiber tail optical fiber is the optical fiber pigtail with GRIN Lens, GRIN Lens and collimation lens battle array Row, chip waveguide coupling, the input and output of optical signal are realized by optical fiber.

Described base is to realize optical switch chip, collimator lens array, free space time delay module, input and output The Best Coupling light path of the parts such as optical fiber pigtail and the reliable substrate mounting platform for being fixedly connected and designing, it should select thermal expansion The relatively low material of coefficient, its mechanical structure should also have relatively low temperature sensitivity.It is optical switch chip, collimator lens array, anti- Penetrate the part such as mirror and substrate, input-output optical fiber tail optical fiber and base is bonded together by glue curing, keep relative position It is fixed.Collimator lens array is located at the both sides of optical switch chip, and chip waveguide emergent light spot is collimated.Input-output optical fiber tail optical fiber It is fixed on the substrate of speculum by glue bonding and is coupled with collimation lens.

The utility model has the advantage of：Compared with traditional " photoswitch+fiber delay time " adjustable light delay, delay stepsize It is greatly improved with delay precision, and small volume, it is in light weight, make it in Optical Controlled Phased Array Antenna system, particularly airborne, star The application for carrying field of radar is very strong；Compared with " photoswitch+fiber waveguide delay " adjustable light delay integrated on piece, technique can Row is much better than, and light delay length is not acted upon by temperature changes.

Brief description of the drawings

Fig. 1 is the tunable optical delay topological structure schematic diagram that the utility model uses.

Fig. 2 is the structural representation of 9-bit optical time delay units example disclosed in the utility model.

Fig. 3 is array of photoswitch arrangement schematic diagram disclosed in the utility model.

Fig. 4 is the vertically oblique polishing schematic diagram of chip fiber waveguide end face disclosed in the utility model.

Fig. 5 is the horizontal tiltedly polishing schematic diagram of example one in chip fiber waveguide end face disclosed in the utility model.

Fig. 6 is the horizontal tiltedly polishing schematic diagram of example two in chip fiber waveguide end face disclosed in the utility model.

Fig. 7 is chip fiber waveguide inclined design schematic diagram disclosed in the utility model.

Fig. 8 is the schematic diagram of free space unit delay path example one disclosed in the utility model.

Fig. 9 is the schematic diagram of free space unit delay path example two disclosed in the utility model.

Figure 10 is lens array schematic diagram disclosed in the utility model.

Figure 11 is base platform structural representation disclosed in the utility model.

Embodiment

The utility model is described in detail below by specific embodiment and with reference to accompanying drawing：

The utility model proposes a kind of new adjustable light delay of " photoswitch+free space optical delay ", it is used Binary system topological structure.As shown in figure 1, smooth delay units at different levels have two delay paths, the difference of both delay lengths is respectively ΔL、2ΔL、4ΔL……2^n-1Δ L, wherein n are the bit numbers of delayer, and Δ L is the tuning step-length of delayer.The 1st in figure, N+1 photoswitch can also be substituted with 2 × 2 photoswitches.

Fig. 2 gives the structural representation of 9-bit optical time delay unit examples disclosed in a utility model.1 is light in figure Switch chip, it is made up of 10 2 × 2 array of photoswitch, 2 be collimator lens array, and 3 be speculum, and 4 put down for mirror substrate Platform, 5 be input/output optical fiber pigtail.As shown in Fig. 22 × 2 optical switch elements can realize " straight-through ", " intersection " two kinds of biographies Defeated state switching, realize that delay path selects by the state switching of every one-level optical switch element.A series of speculums and substrate Platform forms two free space optical time delay modules, respectively positioned at optical switch chip both sides.Optical switch chip and free space optical Time delay module realizes efficient coupling by collimator lens array.Input/output optical fiber pigtail is coupled respectively to by collimation lens 1st grade with the output end of last 1 grade of optical switch element.Accordingly, for the 9-bit optical time delay units of this example, by controlling per one-level The transmission state control of optical switch element, you can realize using Δ L as step-length, 2⁹The adjustable delay of step number.

Array of photoswitch arrangement is as shown in Figure 3.Figure medium spacing a is same 2 × 2 optical switch element, two input/output The centre-to-centre spacing of waveguide, spacing b are the centre-to-centre spacing of the adjacent input/output waveguide of adjacent optical switch element.For ease of collimation lens Array is processed, and all optical switch elements should equidistantly arrange, and figure medium spacing a and b should meet integral multiple relation, wherein less Spacing is the centre-to-centre spacing of adjacent lens in lens array.A kind of simplest situation is given in this example, be i.e. a=b, is also equal to The adjacent lens centre-to-centre spacing of lens array.The controlling mechanism to photoswitch, chip material do not impose any restrictions the utility model, Such as controlling mechanism can be thermo-optic effect, electrooptic effect, plasma dispersion effect, MEMS, and chip material can be that silicon (contains SOI), organic polymer etc..SOI materials, the pass switching technique based on plasma dispersion effect are used in this example.

To increase return loss, incident light and the chip normal line of butt end of chip waveguide can be designed with certain angle, be referred to as Oblique incidence, to make the oblique incidence light expeditiously be coupled into chip fiber waveguide, fiber waveguide should also protect with chip normal line of butt end Hold certain angle.There are a variety of implementations, including vertical tiltedly polishing, horizontal tiltedly polishing to chip end face in the angle of inclination, or Fiber waveguide is just set to keep the angle of inclination with chip normal line of butt end when chip designs.

Fig. 4 gives the schematic diagram that a kind of Waveguide end face to optical switch chip carries out vertical tiltedly polishing example.Figure In 1 be chip substrate material, 2 be chip light waveguide-layer, and 3 be that Chip Vertical tiltedly polishes angle, and 4 be lens array, dot-dash in figure Line has marked the profile signal of launching spot.Vertical tiltedly polishing is that up-narrow and down-wide formula tilts in this example, also can be wide at the top and narrow at the bottom The oblique polishing of formula.Can two end faces of pair chip coupled with lens array carry out vertical oblique polishing, also can only pair with The chip end face of input/output fiber coupling carries out vertical oblique polishing.

Fig. 5 gives a kind of schematic diagram of the horizontal tiltedly polishing example of Waveguide end face progress to optical switch chip.Figure In 1 be chip, 2 be lens array, and 3 be fiber waveguide in chip, and 4 be that chip level tiltedly polishes angle, and figure chain lines mark Light path is illustrated.Can two end faces of pair chip coupled with lens array carry out horizontal oblique polishing, also can only pair with input/ The chip end face of output optical fibre coupling carries out horizontal oblique polishing.

Fig. 6 gives the schematic diagram of the horizontal tiltedly polishing example of another Waveguide end face progress to optical switch chip. 1 is chip in figure, and 2 be lens array, and 3 be fiber waveguide in chip, and 4 be that chip level tiltedly polishes angle, and figure chain lines mark Light path signal.Chip polishing mode is identical with the example shown in Fig. 5, and simply each lens unit of lens array is adopted in this example Designed with tilting, thus it is different coupled to the light path of free space.

Fig. 7 gives a kind of schematic diagram of chip fiber waveguide inclined design example.1 is chip in figure, and 2 be lens array, 3 be fiber waveguide in chip, and figure chain lines have marked light path signal.This example does not carry out oblique polishing to chip, and in core Piece makes input/output fiber waveguide and chip normal line of butt end into certain angle of inclination when designing.This example chips both ends fiber waveguide is equal Inclined design has been carried out, also only pair can carry out inclination optical waveguide design with one end of input/output fiber coupling.

Fig. 8 gives a kind of schematic diagram of free space unit delay path example.One of light timing circuit is：Light Upper road output end of the signal through i-th of (1≤i≤N) optical switch element exports, by Lens Coupling to free space, by certainly Light path reflexed, then the lower road by Lens Coupling to i+1 optical switch element are realized by the speculum of spatial light time delay module Output end.Another light timing circuit is：Optical signal passes through free space optical from the lower road output end output of i-th of photoswitch Coupling is inputted to the upper road input of i+1 photoswitch after light path reflexed in time delay module.For simplicity, this example is set All speculums and incident ray angle at 45 °.As illustrated, 4 symmetrically placed speculums constitute two light paths, its light path Respectively L1, L2, L1 and L2 optical path difference are the adjustable delay length of this grade of delay unit.As it was previously stated, adjacent level delay is single The adjustable delay length of member is incremented by 2 times.In the design, delay unit L1 and L2 at different levels optical path difference need to accurately be controlled and be allowed to Meet that binary system incrementally requires, and L1 or L2 absolute growth need not be controlled strictly.L1 and L2 who that whom grows is short unimportant, only Technique is wanted to realize.This example provides a kind of better simply example, i.e., is that L2 grows compared with L1 per stage of time delay unit.

Fig. 9 gives the schematic diagram of another free space unit delay path example.One of light timing circuit is： Upper road output end of the optical signal through i-th of optical switch element exports, by Lens Coupling to free space, by free space optical The speculum of time delay module realizes light path reflexed, then the upper road output end for passing through Lens Coupling to i+1 optical switch element.Separately One light timing circuit is：Optical signal exports from the lower road output end of i-th of photoswitch, by free space optical time delay module Coupling is inputted to the lower road input of i+1 photoswitch after light path reflexed.

Figure 10 is collimator lens array schematic diagram disclosed in the utility model.As shown in Figure 10, collimation lens is in same side Arrange at a certain distance upwards, lens spacing is corresponding with the spacing of waveguide chip passage.With optical switch chip waveguide spacing phase Corresponding, Figure 10 gives a kind of centre-to-centre spacing equally distributed lens array example.All lens centre axis are in orientation It is parallel to each other, the spheres of lens is aspherical in opposite side in the same side.All focal lengths of lens of lens array can be designed as phase Together, the lens array of non-homogeneous focal length is may be designed in, so that the coupling efficiency of each lens more matches with corresponding light path, this takes Certainly in the balance of coupling efficiency and process complexity.Designed for all focal length of lens identical lens arrays, because different saturating Light path corresponding to mirror is different, and coupling efficiency is also different when light path does not wait.To imitate the coupling of maximum light path and minimum light path Rate difference is sufficiently small, and the spot diameters of lens should select sufficiently large.

Figure 11 is base platform structural representation disclosed in the utility model.As shown in figure 11,1 is platform base, and 2 be light Switch arrays chip, 3 be collimator lens array, and 4 be free space optical time delay module.Base platform can use metal or nonmetallic Material, platform centre are waveguide chip rest area, and both ends are respectively that lens array rest area and free space time delay module are placed Area.Regional retaining surface is parallel, and each face is highly having according to the difference of waveguide chip, lens array and time delay module height Institute is different, in order to which the light path for keeping chip light wave guiding center to be formed with lens centre, mirror center is coplanar.It is whole to make The temperature stability of body device is higher, and optical switch chip, free space optical time delay module, lens array preferably select identical substrate Material, or material similar in coefficient of thermal expansion.

The utility model is described in detail embodiment of above, and those skilled in the art can be according to above-mentioned Illustrate to make the utility model many variations example.Thus, some details in embodiment should not be formed to the utility model Restriction, the utility model will be used as the scope of protection of the utility model using the scope that appended claims define.

Claims (15)

1. A kind of 1. high-precision N-bit adjustable light delays, mainly by optical switch chip, free space optical time delay module, lens array Row, input/output optical fiber pigtail, base composition, wherein N is positive integer, it is characterised in that：

   A) the N-bit adjustable light delays include N level tunable optical delay units, and each light delay unit includes 2 light and is delayed Loop, the optical path difference of 2 light timing circuits are to form the tunable optical delay length of the light delay unit, and N number of tunable optical is prolonged Shi Danyuan optical path difference meets 2⁰ΔL、2¹ΔL……2^N-1Δ L relations, wherein Δ L represent tunable optical delay stepsize；

   B) optical switch chip includes N+1 optical switch element, N+1 optical switch element from top to bottom laid out in parallel, wherein Be coupled with input optical fibre be connected for the 1st optical switch element, be coupled with output optical fibre be connected for the N+1 photoswitch Unit, the 1st optical switch element are 2 × 2 or 1 × 2 photoswitch, and the N+1 optical switch element is 2 × 2 or 2 × 1 Photoswitch, remaining N-1 optical switch element are 2 × 2 photoswitches；

   C) 2 × 2 photoswitch includes 2 inputs and 2 output ends, respectively upper road input, lower road input, upper road Output end, lower road output end, 1 × 2 photoswitch include 1 input and 2 output ends, wherein 2 output ends are respectively upper road Output end, lower road output end, 2 × 1 photoswitches include 2 inputs and 1 output end, wherein 2 inputs are respectively upper road Input, lower road input, the upper road refer to close to the port of upside in 2 inputs or output end, and lower road refers to 2 inputs Or close to the port of downside in output end；

   D) 2 light timing circuits of the i-stage tunable optical delay unit of the adjustable light delay, its loop configuration mode be, Some output end of optical signal through i-th of optical switch element in one of light timing circuit exports, by Lens Coupling extremely Free space, light path reflexed is realized by the speculum of free space optical time delay module, then pass through Lens Coupling to i+1 light Some input of switch element, another output end of optical signal from i-th of photoswitch in another light timing circuit are defeated Go out, inputted by being coupled after light path reflexed in free space optical time delay module to another input of i+1 photoswitch, its Middle i is the positive integer no more than N；

   E) the free space optical delay is made up of two parts light time delay module, is respectively placed in the both sides of optical switch chip, at different levels Light delay unit, which interleaves, to be arranged in two parts time delay module；

   F) the smooth time delay module is made up of a series of speculums with backing material, by rows of mirrors cloth design realize it is at different levels can Dim delay length；

   G) optical switch chip light input/output waveguide and free space optical time delay module described in, both are entered by lens array Row coupling；

   H) optical switch chip, free space optical time delay module, lens array, input/output optical fiber pigtail, by described Base mechanical structure realizes that Best Coupling to each other and relative position are fixed.
2. 2. adjustable light delay as claimed in claim 1, it is characterised in that：Two delays of i-stage tunable optical delay unit Loop configuration mode is that upper road output end of the optical signal in one of light timing circuit through i-th of optical switch element exports, By Lens Coupling to free space, light path reflexed is realized by the speculum of free space optical time delay module, then pass through lens Coupled to the lower road input of i+1 optical switch element, optical signal in another light timing circuit is from i-th photoswitch The output end output of lower road, pass through the upper of coupling input after light path reflexed in free space optical time delay module to i+1 photoswitch Road input.
3. 3. adjustable light delay as claimed in claim 1, it is characterised in that：Two delays of i-stage tunable optical delay unit Loop configuration mode is that upper road output end of the optical signal in one of light timing circuit through i-th of optical switch element exports, By Lens Coupling to free space, light path reflexed is realized by the speculum of free space optical time delay module, then pass through lens Coupled to the upper road input of i+1 optical switch element, optical signal in another light timing circuit is from i-th photoswitch Lower road output end output, by being coupled after light path reflexed in free space optical time delay module under input to i+1 photoswitch Road input.
4. 4. adjustable light delay as claimed in claim 1, the wherein timing circuit of light delay unit can be by adjacent photoswitches Unit+free space is delayed to construct, and can also be constructed by the optical switch element+free space delay being spaced.
5. 5. adjustable light delay as claimed in claim 1, N level tunable opticals delay unit need to only be formed as claimed in claim 1 The optical path difference that does not wait of N number of length, but the sequencing that smooth delay units at different levels are constructed with optical path differences is not intended to limit.
6. 6. adjustable light delay as claimed in claim 1, wherein optical switch chip can utilize thermo-optic effect, electrooptic effect, Plasma dispersion effect or MEMS physical mechanisms are realized, can be based on silicon, organic polymer material is realized.
7. 7. adjustable light delay as claimed in claim 1, it is characterised in that：By being hung down to optical switch chip Waveguide end face Straight tiltedly polishing is to increase return loss.
8. 8. adjustable light delay as claimed in claim 1, it is characterised in that：By entering water-filling to optical switch chip Waveguide end face Oblique polishing is put down to increase return loss.
9. 9. adjustable light delay as claimed in claim 1, it is characterised in that：Design makes optical switch chip input/output waveguide With the angled inclination of chip normal line of butt end.
10. 10. adjustable light delay as claimed in claim 1, it is characterised in that：Each lens unit of lens array is using non- Uniform or uniform focal length.
11. 11. adjustable light delay as claimed in claim 1, it is characterised in that：Free space time delay module is by substrate It is upper to etch forming position graticule to realize being accurately positioned for speculum.
12. 12. adjustable light delay as claimed in claim 1, it is characterised in that：Base and free space time delay module substrate are kept away Exempt to select temperature-sensitive material and mechanical structure.
13. 13. adjustable light delay as claimed in claim 1, it is characterised in that：Input/output optical fiber pigtail is that band self-focusing is saturating The optical fiber pigtail of mirror.
14. 14. adjustable light delay as claimed in claim 8, it is characterised in that：Each lens unit of lens array, which uses, to incline Inclined designs.
15. 15. adjustable light delay as claimed in claim 9, it is characterised in that：Each lens unit of lens array, which uses, to incline Inclined designs.