CN106199831A - A kind of silica-based close-coupled mode step number converter and conversion method - Google Patents

A kind of silica-based close-coupled mode step number converter and conversion method Download PDF

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CN106199831A
CN106199831A CN201610498762.8A CN201610498762A CN106199831A CN 106199831 A CN106199831 A CN 106199831A CN 201610498762 A CN201610498762 A CN 201610498762A CN 106199831 A CN106199831 A CN 106199831A
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waveguide
curved
curved waveguide
width
transmission line
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肖金标
王登峰
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Southeast University
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Southeast University
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/14—Mode converters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

The invention discloses a kind of silica-based close-coupled mode step number converter and conversion method, described transducer is silica-based ridge waveguide structure, including the input waveguide (1) being sequentially connected with, the first y branch waveguide region, tapered waveguide region, the second y branch waveguide region and output waveguide (2).Multimode optical signal inputs from input waveguide, separate at the first y branch waveguide region emergence pattern, and when by tapered waveguide region, produce the change of mode step number, pattern after conversion is retrained by curved waveguide, synthesized by the second y branch waveguide region pattern again, export multimode signal from output waveguide.The transducer of the present invention has simple in construction, makes that tolerance is good, compact is easy to the advantages such as integrated, low cost, loss be low, can realize large-scale fiber waveguide integrated.

Description

A kind of silica-based close-coupled mode step number converter and conversion method
Technical field
The present invention relates to a kind of silica-based close-coupled mode step number converter and conversion method, belong to integrated optics technique field.
Background technology
In recent years, in optical communication field, all-optical network caused great interest.The advantage of all-optical network is the pole of bandwidth Big expansion and low latency end to end.For all-optical network, increasing focus is put into the research of all-optical device.Branch Waveguide is the key component of integrated optics technique.By coupling effect, branch-waveguide is designed to photoswitch, wavelength selects filtering Device, gate etc..Mode step number converter is also another good research direction of all-optical device.The low-light of photonic integrated circuits Sub-device, owing to its device density is high and low-power consumption, has attracted the application in terms of various optic communication.
Branch-waveguide can be the single mode in multiple waveguide with the multimode in space division single channel waveguide.These branch-waveguides are permissible It is used in multimode waveguide and carrys out selective excitation guided mode.The characteristic of the mode treatment of this uniqueness, can apply in multiplexing/demultiplex With technically.Alternatively, it is also possible to realize multiport photoswitch by hot light or Electro-optical Modulation.One multichannel branch-waveguide, edge Multimode region and be transferred to single mode stub area, it is possible to become mode splitter；Light transmits in reverse direction, it is possible to regard mould as Formula synthesizer.
Mode step number converter can be divided into active optical component and Passive Optical Components, Passive Optical Components be a kind of compact conformation, The advantages such as easy of integration, tolerance is good.Structure based on silica-based close-coupled mode step number converter proposes in photonic integrated circuits field It is innovative research and contribution.
Summary of the invention
Goal of the invention: in order to overcome the deficiencies in the prior art, the present invention provides a kind of silica-based close-coupled mode step number Transducer and conversion method, this transducer has simple in construction, makes that tolerance is good, compact is easy to integrated, low cost, loss Low advantage, can realize large-scale fiber waveguide integrated.
Technical scheme: for achieving the above object, the technical solution used in the present invention is:
A kind of silica-based close-coupled mode step number converter, described transducer is silica-based ridge waveguide structure, including be sequentially connected with Input waveguide (1), the first y branch waveguide region, tapered waveguide region, the second y branch waveguide region and output waveguide (2). Described input waveguide (1) is used for input optical signal, and described output waveguide (2) is used for exporting optical signal.
Described first y branch waveguide region includes the first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the 4th curved waveguide (6), and described second y branch waveguide region includes the 5th curved waveguide (7), the 6th curved waveguide (8), the 7th curved waveguide (9), the 8th curved waveguide (10).Described tapered waveguide region include the first tapered transmission line (11), Two tapered transmission lines (12), triconic waveguide (13), the 4th tapered transmission line (14).
Described first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the 4th curved waveguide (6) by Top to bottm according to being arranged on the outfan of input waveguide (1), and described first curved waveguide (3), the second curved waveguide (4), the 3rd Curved waveguide (5), the cross-sectional width of the 4th curved waveguide (6) narrow from the width the most successively.And described 5th bending wave Lead (7), the 6th curved waveguide (8), the 7th curved waveguide (9), the 8th curved waveguide (10) from top to bottom according to being arranged on output wave Lead the input of (2), and described 5th curved waveguide (7), the 6th curved waveguide (8), the 7th curved waveguide (9), the 8th bending The cross-sectional width of waveguide (10) narrows from the width the most successively.
It is connected by the first tapered transmission line (11) between described first curved waveguide (3) and the 5th curved waveguide (7), and institute The tapered tip stating the first tapered transmission line (11) points to the 5th curved waveguide (7).Described second curved waveguide (4) and the 6th bending Connected by the second tapered transmission line (12) between waveguide (8), and the tapered tip of described second tapered transmission line (12) points to the 6th Curved waveguide (8).It is connected by triconic waveguide (13) between described 3rd curved waveguide (5) and the 7th curved waveguide (9), And the tapered tip of described triconic waveguide (13) points to the 7th curved waveguide (9).Described 4th curved waveguide (6) and the 8th Connected by the 4th tapered transmission line (14) between curved waveguide (10), and the tapered tip of described 4th tapered transmission line (14) is pointed to 8th curved waveguide (10).
Preferred: described input waveguide (1), the first y branch waveguide region, tapered waveguide region, the second y branch waveguide district Territory and output waveguide (2) are filled with medium.
Preferred: the width of described input waveguide (1) equal to the first curved waveguide (3), the second curved waveguide (4), the 3rd Curved waveguide (5), the width sum of the 4th curved waveguide (6).Or the width of described input waveguide (1) is equal to the 5th bending wave Lead (7), the 6th curved waveguide (8), the 7th curved waveguide (9), the width sum of the 8th curved waveguide (10).
The width of described output waveguide (2) is equal to the first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the width sum of the 4th curved waveguide (6).Or the width of described output waveguide (2) equal to the 5th curved waveguide (7), the Six curved waveguides (8), the 7th curved waveguide (9), the width sum of the 8th curved waveguide (10).
Preferred: described first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the 4th bending wave Lead (6), the 5th curved waveguide (7), the 6th curved waveguide (8), the 7th curved waveguide (9), the 8th curved waveguide (10) are arc Shape structure, respective width is determined by the pattern in its corresponding waveguide respectively.
Preferred: described first tapered transmission line (11), the second tapered transmission line (12), triconic waveguide (13), the 4th cone Shape waveguide (14) is pyramidal structure, and the curved waveguide width that respective width is connected by it respectively determines.
Preferred: the width of described input waveguide (1) or the width of output waveguide (2) meet:
W = &Sigma; i = 0 3 w i , w i = w 0 - &delta; &times; i i = 0 , 1 , 2 , 3 ; m ( m - 1 ) &delta; < 2 w 0 < &lambda; n s 2 - n b 2 .
Wherein, W is width or the width of output waveguide (2), the w of input waveguide (1)iIt is the width of single-mode curved waveguide, i =0,1,2,3；w0, w1, w2, w3It is sequentially reduced, w0, w1, w2, w3Represent the first curved waveguide (3), the second curved waveguide successively (4), the 3rd curved waveguide (5), the width of the 4th curved waveguide (6) or w0, w1, w2, w3Represent the 8th curved waveguide successively (10), the 7th curved waveguide (9), the 6th curved waveguide (8), the width of the 5th curved waveguide (7).M is mode step number, and δ is adjacent Stand out between waveguide, λ is free space wavelength, nsIt is sandwich layer effective refractive index, nbIt it is cladding-effective-index.
Preferred: described first tapered transmission line (11), the second tapered transmission line (12), triconic waveguide (13), the 4th cone The cone-shaped model of shape waveguide (14) is:
&alpha; i ( z ) = w i + 3 + ( w i - w i + 3 ) L z , i = 0 w i + 1 + ( w i - w i + 1 ) L z , i = 1 .
Wherein, αiIt is the diameter of tapered transmission line, wiIt is the width of single-mode curved waveguide, i=0,1,2,3；w0, w1, w2, w3Depend on Secondary expression the first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the width of the 4th curved waveguide (6) or Person w0, w1, w2, w3Represent the 8th curved waveguide (10), the 7th curved waveguide (9), the 6th curved waveguide (8), the 5th bending successively The width of waveguide (7), z is the transmission direction of light, the length of L tapered transmission line.
The conversion method of a kind of silica-based close-coupled mode step number converter, multimode optical signal inputs from input waveguide 1, first Y branch waveguide region emergence pattern separates, and propagates along curved waveguide, and produces the change of mode step number when by tapered waveguide region Changing, the corresponding relation of mode step number conversion is TE0,0->TE3,0, TE1,0->TE2,0, TE2,0->TE1,0, TE3,0->TE0,0, or mode step The corresponding relation of number conversion is TE0,0->TE3,0, TE1,0->TE0,0, TE2,0->TE1,0, TE3,0->TE2,0；Pattern after conversion is subject to To the constraint of curved waveguide, synthesized by the second y branch waveguide region pattern again, export multimode signal from output waveguide 2.
Beneficial effect: the one silica-based close-coupled mode step number converter of present invention offer and conversion method, 2, have following Beneficial effect:
1, the core component of transducer is ridge waveguide structure, has the highest reliability, and radiation loss is little, improves Integrated Light The stability on road.
2, converter design is arcuate structure, can effectively reduce in tradition mode step number converter, branch-waveguide and conical wave When leading connection, the optical mode that between waveguide, angle causes too greatly radiates serious situation so that the device conversion efficiency of making is more High.
3, separator is designed as arcuate structure, and compared with tradition mode step number converter, curved waveguide has than oblique straight wave guide Lower loss, is effectively improved the luminous power of converted mode, has higher Application effects.
4, separator is designed as arcuate structure, can realize transducer overall dimensions and reduce significantly, shortens transmission light Journey, thus reduce optical mode radiation so that the device of making be more compact, easy to integrated, conversion efficiency is high.
5, the flexible design, easy to use of transducer.Mode step number converter is can to use the device, i.e. input can be as defeated Going out end, outfan also can be as input, and both forward and reverse directions all can realize mode step conversion, and design uses flexibly.
Accompanying drawing explanation
Fig. 1 is the structural representation of the close-coupled mode step number converter of first example of the present invention.
Fig. 2 is the cross sectional representation of the silica-based ridge waveguide structure of first example of the present invention.
Fig. 3 is TE in first example of the present invention0,0->TE3,0Waveform change and optical power change figure during mode step number conversion.
Fig. 4 is TE in first example of the present invention1,0->TE2,0Waveform change and optical power change figure during mode step number conversion.
Fig. 5 is TE in first example of the present invention2,0->TE1,0Waveform change and optical power change figure during mode step number conversion.
Fig. 6 is TE in first example of the present invention3,0->TE0,0Waveform change and optical power change figure during mode step number conversion.
Fig. 7 is the structural representation of second example of the present invention.
In figure, label is described as follows:
1 input waveguide, 2 output waveguides, 3-the first curved waveguide, 4 second curved waveguides, 5 the 3rd curved waveguides, 6-the 4th curved waveguide, 7-the 5th curved waveguide, 8-the 6th curved waveguide, 9-the 7th curved waveguide, 10-the 8th bends Waveguide, 11-the first tapered transmission line, 12-the second tapered transmission line, 13-triconic waveguide, 14-the 4th tapered transmission line, 15 Air, 16 overlying stratas, 17 sandwich layers, 18 times coating, 19 silicon substrates.
Detailed description of the invention
Below in conjunction with the accompanying drawings and specific embodiment, it is further elucidated with the present invention, it should be understood that these examples are merely to illustrate this Invention rather than limit the scope of the present invention, after having read the present invention, various to the present invention of those skilled in the art The amendment of the equivalent form of value all falls within the application claims limited range.
A kind of silica-based close-coupled mode step number converter, as it is shown in figure 1, described transducer is silica-based ridge waveguide structure, including Input waveguide the 1, first y branch waveguide region of being sequentially connected with, tapered waveguide region, the second y branch waveguide region and output Waveguide 2.Described input waveguide 1 is for input optical signal, and described output waveguide 2 is used for exporting optical signal.
Described first y branch waveguide region include first curved waveguide the 3, second curved waveguide 4, the 3rd curved waveguide 5, Four curved waveguides 6, and described second y branch waveguide region includes the 5th curved waveguide the 7, the 6th curved waveguide the 8, the 7th bending wave Lead the 9, the 8th curved waveguide 10.Described tapered waveguide region includes first tapered transmission line the 11, second tapered transmission line 12, triconic Waveguide the 13, the 4th tapered transmission line 14.
Described first curved waveguide the 3, second curved waveguide the 4, the 3rd curved waveguide the 5, the 4th curved waveguide 6 depends on from top to bottom It is arranged on the outfan of input waveguide 1, and described first curved waveguide the 3, second curved waveguide the 4, the 3rd curved waveguide the 5, the 4th The cross-sectional width of curved waveguide 6 narrows from the width the most successively.And described 5th curved waveguide the 7, the 6th curved waveguide 8, 7th curved waveguide the 9, the 8th curved waveguide 10 depends on the input being arranged on output waveguide 2, and described 5th bending from top to bottom The cross-sectional width of waveguide the 7, the 6th curved waveguide the 8, the 7th curved waveguide the 9, the 8th curved waveguide 10 is the most successively by width Narrow.The duct width limited selected from mode step number is as the width of curved waveguide.
It is connected by the first tapered transmission line 11 between described first curved waveguide 3 and the 5th curved waveguide 7, and described first The tapered tip of tapered transmission line 11 points to the 5th curved waveguide 7.Lead between described second curved waveguide 4 and the 6th curved waveguide 8 Cross the second tapered transmission line 12 to connect, and the tapered tip of described second tapered transmission line 12 points to the 6th curved waveguide 8.Described 3rd It is connected by triconic waveguide 13 between curved waveguide 5 with the 7th curved waveguide 9, and the taper of described triconic waveguide 13 The 7th curved waveguide 9 is pointed on top.By the 4th tapered transmission line 14 between described 4th curved waveguide 6 and the 8th curved waveguide 10 Connect, and the tapered tip of described 4th tapered transmission line 14 points to the 8th curved waveguide 10.
Optical signal inputs from input waveguide 1, by first curved waveguide the 3, second curved waveguide the 4, the 3rd curved waveguide 5, modal cutoff is produced during four curved waveguides 6 respectively, by first tapered transmission line the 11, second tapered transmission line 12, third hand tap Shape waveguide the 13, the 4th tapered transmission line 14 produces mode step number respectively and converts, finally by the 5th curved waveguide the 7, the 6th bending wave Lead the 8, the 7th curved waveguide the 9, the 8th curved waveguide 10 and produce pattern synthesis.
As it is shown in figure 1, described first curved waveguide 3 (width w0) corresponding to the 5th curved waveguide 7 (width w3).Described Two curved waveguide 4 (width w1) the 6th curved waveguide 8 (width w2).Described 3rd curved waveguide 5 (width w2) curved corresponding to the 7th Bent waveguide 9 (width w1).Described 4th curved waveguide 6 (width w3) corresponding to the 8th curved waveguide 10 (width w0)。
Described input waveguide the 1, first y branch waveguide region, tapered waveguide region, the second y branch waveguide region and defeated Go out waveguide 2 and be filled with medium.
The width of described input waveguide 1 is equal to first curved waveguide the 3, second curved waveguide the 4, the 3rd curved waveguide the 5, the 4th The width sum of curved waveguide 6.Or the width of described input waveguide 1 equal to the 5th curved waveguide 7, the 6th curved waveguide 8, the The width sum of seven curved waveguide the 9, the 8th curved waveguides 10.
The width of described output waveguide 2 is equal to first curved waveguide the 3, second curved waveguide the 4, the 3rd curved waveguide the 5, the 4th The width sum of curved waveguide 6.Or the width of described output waveguide 2 equal to the 5th curved waveguide 7, the 6th curved waveguide 8, the The width sum of seven curved waveguide the 9, the 8th curved waveguides 10.
Described first curved waveguide the 3, second curved waveguide the 4, the 3rd curved waveguide the 5, the 4th curved waveguide the 6, the 5th bending Waveguide the 7, the 6th curved waveguide the 8, the 7th curved waveguide the 9, the 8th curved waveguide 10 is arcuate structure, respective width respectively by Pattern in its corresponding waveguide determines.Arcuate structure refers to the one section of curved waveguide using circular arc function to be made, its Matter is the function expression x of a circlei 2+zi 2=Ri 2, wherein xi, zi, RiIt is first curved waveguide the 3, second curved waveguide respectively 4, the 3rd curved waveguide the 5, the 4th curved waveguide the 6, the 5th curved waveguide the 7, the 6th curved waveguide the 8, the 7th curved waveguide the 9, the 8th The radius of the x coordinate of curved waveguide 10, z coordinate and affiliated circle.Relevant parameter by appropriate design arcuate structure: bending radius RiWith arc length, it is possible to be greatly reduced the length of transducer, and reduce the angle between the waveguide of junction, can effectively reduce radiation Mould.Pyramidal structure is the one section of tapered transmission line utilizing linear function to be made, and its expression formula is αi(z)=wstart+(wend- wstart) × z/L, wherein αi(z), wstart, wend, L is first tapered transmission line the 11, second tapered transmission line 12, triconic ripple respectively Lead the diameter of the 13, the 4th tapered transmission line 14, start width, terminal end width and length.Phase by appropriate design pyramidal structure Related parameter: length L, it is possible to successfully realize the conversion between low high mode step number.Appropriate design curved waveguide and tapered transmission line, thus Transducer is made to more they tend to miniaturization, easy of integration.
Described first tapered transmission line the 11, second tapered transmission line 12, triconic waveguide the 13, the 4th tapered transmission line 14 are list Mode interference waveguide, its shape is pyramidal structure, and the curved waveguide width that respective width is connected by it respectively determines.
The width of described input waveguide 1 or the width of output waveguide 2 meet:
W = &Sigma; i = 0 3 w i , w i = w 0 - &delta; &times; i i = 0 , 1 , 2 , 3 ; m ( m - 1 ) &delta; < 2 w 0 < &lambda; n s 2 - n b 2 .
Wherein, W is width or the width of output waveguide 2, the w of input waveguide 1iIt is the width of single-mode curved waveguide, i=0, 1,2,3；w0, w1, w2, w3It is sequentially reduced, w0, w1, w2, w3Represent that first curved waveguide the 3, second curved waveguide the 4, the 3rd is curved successively The width of bent waveguide the 5, the 4th curved waveguide 6 or w0, w1, w2, w3Represent the 8th curved waveguide the 10, the 7th curved waveguide successively 9, the width of the 6th curved waveguide the 8, the 5th curved waveguide 7.M is mode step number, and δ is the stand out between adjacent waveguide, and λ is freely Space wavelength, nsIt is sandwich layer effective refractive index, nbIt it is cladding-effective-index.
Described first tapered transmission line the 11, second tapered transmission line 12, the taper of triconic waveguide the 13, the 4th tapered transmission line 14 Model is:
&alpha; i ( z ) = w i + 3 + ( w i - w i + 3 ) L z , i = 0 w i + 1 + ( w i - w i + 1 ) L z , i = 1 .
Wherein, αiIt is the diameter of tapered transmission line, wiIt is the width of single-mode curved waveguide, i=0,1,2,3；w0, w1, w2, w3Depend on The width of secondary expression the first curved waveguide the 3, second curved waveguide the 4, the 3rd curved waveguide the 5, the 4th curved waveguide 6 or w0, w1, w2, w3Represent the width of the 8th curved waveguide the 10, the 7th curved waveguide the 9, the 6th curved waveguide the 8, the 5th curved waveguide 7, z successively It is the transmission direction of light, the length of L tapered transmission line.By simulation results show, the Design of length long enough of tapered transmission line is to protect Card mode step number conversion efficiency reaches more than 90%.
The conversion method of a kind of silica-based close-coupled mode step number converter, multimode optical signal inputs from input waveguide 1, first Y branch waveguide region emergence pattern separates, and propagates along curved waveguide, and produces the change of mode step number when by tapered waveguide region Changing, the corresponding relation of mode step number conversion is TE0,0->TE3,0, TE1,0->TE2,0, TE2,0->TE1,0, TE3,0->TE0,0, (i.e. TE0,0 Mould is converted to TE3,0Mould, TE1,0Mould is converted to TE2,0Mould, TE2,0Mould is converted to TE1,0Mould, TE3,0Mould is converted to TE0,0Mould), conversion After pattern retrained by curved waveguide, by the second y branch waveguide region pattern again synthesize, export from output waveguide 2 Multimode signal.
Device selects the input waveguide 1 of multimode, output waveguide 2, and polarization insensitive, bandwidth are high, it is good to make tolerance, have Big working range.Warp architecture designs, and reduces device length, and compactedness is good.Tapered transmission line (first for mode step number conversion Tapered transmission line the 11, second tapered transmission line 12, triconic waveguide the 13, the 4th tapered transmission line 14), make use of interference to imitate from imaging Should, the length of transducer can be substantially reduced, make device miniaturization.For the y branch waveguide of modal cutoff/synthesis, utilize bending Waveguide (first curved waveguide the 3, second curved waveguide 4, the 3rd curved waveguide 5, the 4th curved waveguide 6, the 5th curved waveguide 7, Six curved waveguide the 8, the 7th curved waveguide the 9, the 8th curved waveguides 10) connect smooth feature, radiation mode can be greatly reduced, carry The conversion efficiency of high transducer.The luminous power of output waveguide 2 and Mode variation, can reflect the situation of change of pattern, conversion Efficiency is high.
Present configuration curved waveguide as the parts of y branch waveguide, compositional model separation/synthesis device, then waveguide Device length can reduce and not show bad phenomenon.
Present configuration introduces two curved waveguides, then optical signal at tapered transmission line two ends along optical signal transmission direction Loss can reduce and not show bad phenomenon.
Fig. 3 is TE in first example of the present invention0,0->TE3,0Waveform change and optical power change figure during mode step number conversion. Fig. 4 is TE in first example of the present invention1,0->TE2,0Waveform change and optical power change figure during mode step number conversion.Fig. 5 is this TE in bright first example2,0->TE1,0Waveform change and optical power change figure during mode step number conversion.Fig. 6 is the present invention first TE in example3,0->TE0,0Waveform change and optical power change figure during mode step number conversion.Data above shows that having of the present invention is excellent Good mode step number conversion efficiency, and less optical power loss.
Multimode switching device have bandwidth high, to polarization insensitive, make the advantages such as tolerance is good, but, usually by In branch-waveguide quantity and modal cutoff/synthesize and the requirement of length changed, the length value of multimode interference couplers can reach Millimeter even centimetre rank, the most unfavorable for making compact sensor.So present invention theory based on design is propped up Hold, it is proposed that the optimization design reducing device length with reducing radiation mode: use curved waveguide as y branch waveguide parts.
Fig. 7 is second example of the present invention, by the corresponding curved waveguide width corresponding relation weight at tapered transmission line two ends Newly design, it is characterised in that: the curved waveguide 3,4,5,6,7,8,9,10 of described transducer is arcuate structure, and waveguide 3 is (wide Degree w0) corresponding to waveguide 7 (width w1), waveguide 4 (width w1) corresponding to waveguide 8 (width w2), waveguide 5 (width w2) corresponding to ripple Lead 9 (width w3), waveguide 6 (width w3) corresponding to waveguide 10 (width w0).With the corresponding relation of change mode step number conversion it is TE0,0->TE1,0, TE1,0->TE2,0, TE2,0->TE3,0, TE3,0->TE1,0.Meet different performance demand, and simultaneously need to again The size of design tapered transmission line, the transducer of making is also close-coupled, it is simple to integrated, and conversion efficiency is high.
The mode step number conversion device of the tapered transmission line of present invention design has the highest reliability, has in integreted phontonics field There is the biggest potential using value.Further, since the good characteristics such as this structure low-loss, densification may bring integrated technique Improvement, produce in enormous quantities reduce cost, it is achieved commercialization, be widely used in real life.On this basis, also Optics, calorifics, electrical functions can be integrated in identical platform to obtain active device experimentally, be light subset further Circuit field and other association area is become to open up novel road.
The above is only the preferred embodiment of the present invention, it should be pointed out that: for the ordinary skill people of the art For Yuan, under the premise without departing from the principles of the invention, it is also possible to make some improvements and modifications, these improvements and modifications also should It is considered as protection scope of the present invention.

Claims (8)

1. a silica-based close-coupled mode step number converter, it is characterised in that: described transducer is silica-based ridge waveguide structure, including depending on The input waveguide (1) of secondary connection, the first y branch waveguide region, tapered waveguide region, the second y branch waveguide region and output Waveguide (2)；Described input waveguide (1) is used for input optical signal, and described output waveguide (2) is used for exporting optical signal；
Described first y branch waveguide region include the first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), 4th curved waveguide (6), and described second y branch waveguide region include the 5th curved waveguide (7), the 6th curved waveguide (8), Seven curved waveguides (9), the 8th curved waveguide (10)；Described tapered waveguide region includes the first tapered transmission line (11), the second taper Waveguide (12), triconic waveguide (13), the 4th tapered transmission line (14)；
Described first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the 4th curved waveguide (6) are arrived from above The lower outfan being arranged on input waveguide (1) that depends on, and described first curved waveguide (3), the second curved waveguide (4), the 3rd bending Waveguide (5), the cross-sectional width of the 4th curved waveguide (6) narrow from the width the most successively；And described 5th curved waveguide (7), the 6th curved waveguide (8), the 7th curved waveguide (9), the 8th curved waveguide (10) are from top to bottom according to being arranged on output waveguide (2) input, and described 5th curved waveguide (7), the 6th curved waveguide (8), the 7th curved waveguide (9), the 8th bending wave The cross-sectional width leading (10) narrows from the width the most successively；
It is connected by the first tapered transmission line (11) between described first curved waveguide (3) and the 5th curved waveguide (7), and described the The tapered tip of one tapered transmission line (11) points to the 5th curved waveguide (7)；Described second curved waveguide (4) and the 6th curved waveguide (8) connected by the second tapered transmission line (12) between, and the tapered tip of described second tapered transmission line (12) points to the 6th bending Waveguide (8)；It is connected by triconic waveguide (13) between described 3rd curved waveguide (5) and the 7th curved waveguide (9), and institute The tapered tip stating triconic waveguide (13) points to the 7th curved waveguide (9)；Described 4th curved waveguide (6) and the 8th bending Connected by the 4th tapered transmission line (14) between waveguide (10), and the tapered tip of described 4th tapered transmission line (14) points to the 8th Curved waveguide (10).
Silica-based close-coupled mode step number converter the most according to claim 1, it is characterised in that: described input waveguide (1), One y branch waveguide region, tapered waveguide region, the second y branch waveguide region and output waveguide (2) are filled with medium.
Silica-based close-coupled mode step number converter the most according to claim 1, it is characterised in that: described input waveguide (1) Width is equal to the first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the width of the 4th curved waveguide (6) Sum；Or the width of described input waveguide (1) is equal to the 5th curved waveguide (7), the 6th curved waveguide (8), the 7th bending wave Lead (9), the width sum of the 8th curved waveguide (10)；
The width of described output waveguide (2) equal to the first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), The width sum of the 4th curved waveguide (6)；Or the width of described output waveguide (2) is equal to the 5th curved waveguide (7), the 6th curved Bent waveguide (8), the 7th curved waveguide (9), the width sum of the 8th curved waveguide (10).
Silica-based close-coupled mode step number converter the most according to claim 1, it is characterised in that: described first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the 4th curved waveguide (6), the 5th curved waveguide (7), the 6th bending Waveguide (8), the 7th curved waveguide (9), the 8th curved waveguide (10) are arcuate structure, and respective width is corresponding by it respectively Pattern in waveguide determines.
Silica-based close-coupled mode step number converter the most according to claim 1, it is characterised in that: described first tapered transmission line (11), the second tapered transmission line (12), triconic waveguide (13), the 4th tapered transmission line (14) are pyramidal structure, respective width The curved waveguide width that degree is connected by it respectively determines.
Silica-based close-coupled mode step number converter the most according to claim 1, it is characterised in that: described input waveguide (1) The width of width or output waveguide (2) meets:
W = &Sigma; i = 0 3 w i , w i = w 0 - &delta; &times; i
i = 0 , 1 , 2 , 3 ; m ( m - 1 ) &delta; < 2 w 0 < &lambda; n s 2 - n b 2 ;
Wherein, W is width or the width of output waveguide (2), the w of input waveguide (1)iIt is the width of single-mode curved waveguide, i=0, 1,2,3；w0, w1, w2, w3It is sequentially reduced, w0, w1, w2, w3Represent successively the first curved waveguide (3), the second curved waveguide (4), Three curved waveguides (5), the width of the 4th curved waveguide (6) or w0, w1, w2, w3Represent successively the 8th curved waveguide (10), the Seven curved waveguides (9), the 6th curved waveguide (8), the width of the 5th curved waveguide (7)；M is mode step number, and δ is between adjacent waveguide Stand out, λ is free space wavelength, nsIt is sandwich layer effective refractive index, nbIt it is cladding-effective-index.
Silica-based close-coupled mode step number converter the most according to claim 1, it is characterised in that: described first tapered transmission line (11), the second tapered transmission line (12), triconic waveguide (13), the cone-shaped model of the 4th tapered transmission line (14) are:
&alpha; i ( z ) = w i + 3 + ( w i - w i + 3 ) L z , i = 0 w i + 1 + ( w i - w i + 1 ) L z , i = 1 ;
Wherein, αiIt is the diameter of tapered transmission line, wiIt is the width of single-mode curved waveguide, i=0,1,2,3；w0, w1, w2, w3Table successively Show the first curved waveguide (3), the second curved waveguide (4), the 3rd curved waveguide (5), the width of the 4th curved waveguide (6) or w0, w1, w2, w3Represent the 8th curved waveguide (10), the 7th curved waveguide (9), the 6th curved waveguide (8), the 5th bending wave successively Leading the width of (7), z is the transmission direction of light, the length of L tapered transmission line.
8. a conversion method based on the silica-based close-coupled mode step number converter described in claim 1, it is characterised in that: multimode Optical signal inputs from input waveguide 1, separates at the first y branch waveguide region emergence pattern, propagates along curved waveguide, and logical Producing the change of mode step number when crossing tapered waveguide region, the corresponding relation of mode step number conversion is TE0,0->TE3,0, TE1,0->TE2,0, TE2,0->TE1,0, TE3,0->TE0,0, or the corresponding relation of mode step number conversion is TE0,0->TE3,0, TE1,0->TE0,0, TE2,0-> TE1,0, TE3,0->TE2,0；Pattern after conversion is retrained by curved waveguide, by the second y branch waveguide region pattern again Synthesis, exports multimode signal from output waveguide 2.
CN201610498762.8A 2016-06-29 2016-06-29 A kind of silica-based close-coupled mode step number converter and conversion method Pending CN106199831A (en)

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CN113406751A (en) * 2021-05-31 2021-09-17 西安理工大学 Optical fiber and waveguide coupling spot size converter with 850nm waveband

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CN107290825A (en) * 2017-06-15 2017-10-24 云南大学 Mode converter based on bipyramid combining structure
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