CN107422421B - Sparse wavelength division multiplexer based on bending directional coupler - Google Patents
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- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
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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
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
- G02B6/29346—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means operating by wave or beam interference
Abstract
The invention discloses a sparse wavelength division multiplexer based on a curved directional coupler. The invention is composed of cascade connection of two-stage filters, wherein the first-stage filter comprises a first Mach-Zehnder interferometer, and the second-stage filter comprises a second Mach-Zehnder interferometer and a third Mach-Zehnder interferometer; the Mach-Zehnder interferometers are composed of sixteen connecting waveguides, eight coupling waveguides and six phase-shifting waveguides. The optical splitter in the mach-zehnder interferometer is constituted by a directional coupler based on a curved waveguide, the splitting ratio of which remains substantially unchanged over a wide spectral range. The coarse wavelength division multiplexer provided by the invention has the characteristics of low crosstalk, low loss, compact structure and simple processing, and meets the actual requirements in the fields of optical communication, integrated optics and the like.
Description
Technical Field
The invention belongs to the field of optical communication, and particularly relates to a cascade Mach-Zehnder interferometer type four-channel coarse wavelength division multiplexer based on a curved waveguide directional coupler.
Background
With the rapid development of optical fiber communication, there is an increasing demand for communication bandwidth. The advent of wavelength division multiplexing (Wavelength Division Multiplexing, WDM) technology has multiplied the bandwidth of optical fiber communications. Multiple signals with channel spacing less than 0.8nm can be transmitted in the same optical fiber by using dense wavelength division multiplexing (Dense Wavelength Division Multiplexing, DWDM) technology. But the cost of the dense wavelength division multiplexing technology is high, and the dense wavelength division multiplexing technology is not suitable for being used in a short-distance network. Coarse wavelength division multiplexing (Coarse Wavelength Division Multiplexing, CWDM) is a wavelength division multiplexing technique with a large channel spacing. Compared with dense wavelength division multiplexing, the technology can effectively reduce the cost of devices, and is a low-cost wavelength division multiplexing technology for a short-distance network. The coarse wavelength division multiplexing technology with 20nm channel spacing is used for short-distance interconnection such as data center communication and the like due to the fact that the coarse wavelength division multiplexing technology has large processing tolerance and does not need temperature control.
The currently common 20nm channel-spacing CWDM devices include thin film filters and optical filters based on planar optical waveguides. Thin film filters are a more traditional solution and are widely used in wavelength division multiplexing systems. However, such CWDM devices are relatively large in size, complex to manufacture, and expensive. Optical filters based on planar optical waveguides have received much attention in recent years, and have the advantages of being integrable, low in cost, and easy to process. Common planar optical waveguide optical filters include arrayed waveguide gratings (Arrayed Waveguide Grating, AWG), waveguide bragg gratings (Waveguide Bragg Grating) and Mach-Zehnder Interferometer, MZI. Arrayed waveguide gratings have the advantage of low crosstalk, but the loss of such devices is large. Waveguide Bragg gratings are smaller in size but require more elaborate processing and crosstalk is greater. In comparison, mach-Zehnder interferometers have both smaller device size, lower cross-talk, and lower loss. However, for conventional mach-zehnder interferometers, their practical performance is limited by the optical splitter. The beam splitter based on the directional coupler (Directional Coupler) has lower loss, but has stronger wavelength sensitivity than the beam splitter. For a multimode interference coupler (Multi-mode Interference Coupler, MMI) based optical splitter, its splitting ratio is insensitive to wavelength but has a large loss. This makes the conventional mach-zehnder interferometer unable to achieve ideal device performance, and difficult to meet practical application requirements.
Disclosure of Invention
The invention aims to provide a sparse wavelength division multiplexer based on a curved directional coupler, which utilizes the curved waveguide directional coupler to realize specific proportion light splitting within a wide spectrum range, thereby realizing four-channel coarse wavelength division multiplexing with low crosstalk and low loss.
The technical scheme adopted for solving the technical problems is as follows:
the invention consists of a cascade of two-stage filters, wherein the first stage filter comprises a first Mach-Zehnder interferometer (I), and the second stage filter comprises a second Mach-Zehnder interferometer (II) and a third Mach-Zehnder interferometer (III).
The input optical waveguide (1) is connected to a first connection waveguide (1101) in the first Mach-Zehnder interferometer (I). The eighth connecting waveguide (1108) and the sixteenth connecting waveguide (1116) in the first Mach-Zehnder interferometer (I) are respectively connected with the first connecting waveguide (2101) in the second Mach-Zehnder interferometer (II) and the first connecting waveguide (3101) in the third Mach-Zehnder interferometer (III) through the first cascade waveguide (2) and the second cascade waveguide (3). An eighth connecting waveguide (2108) and a sixteenth connecting waveguide (2116) in the second Mach-Zehnder interferometer (II) are connected to the first output waveguide (4) and the second output waveguide (5), respectively. An eighth connecting waveguide (3108) and a sixteenth connecting waveguide (3116) in the third mach-zehnder interferometer (III) are connected to the third output waveguide (6) and the fourth output waveguide (7), respectively.
The mach-zehnder interferometers are each composed of sixteen connecting waveguides (first connecting waveguide, …, sixteenth connecting waveguide), eight coupling waveguides (first coupling waveguide, …, eighth coupling waveguide), and six phase shifting waveguides (first phase shifting waveguide, …, sixth phase shifting waveguide).
In the i Mach-Zehnder interferometer, a first connection waveguide (i 101), a first coupling waveguide (i 21), a second connection waveguide (i 102), a first phase shift waveguide (i 31), a third connection waveguide (i 103), a second coupling waveguide (i 22), a fourth connection waveguide (i 104), a second phase shift waveguide (i 32), a fifth connection waveguide (i 105), a third coupling waveguide (i 23), a sixth connection waveguide (i 106), a third phase shift waveguide (i 33), a seventh connection waveguide (i 107), a fourth coupling waveguide (i 24), and an eighth connection waveguide (i 108) are sequentially connected in an end-to-end manner. A ninth connection waveguide (i 109), a fifth coupling waveguide (i 25), a tenth connection waveguide (i 110), a fourth phase shift waveguide (i 34), an eleventh connection waveguide (i 111), a sixth coupling waveguide (i 26), a twelfth connection waveguide (i 112), a fifth phase shift waveguide (i 35), a thirteenth connection waveguide (i 113), a seventh coupling waveguide (i 27), a fourteenth connection waveguide (i 114), a sixth phase shift waveguide (i 36), a fifteenth connection waveguide (i 115), an eighth coupling waveguide (i 28), and a sixteenth connection waveguide (i 116) in the i mach-zehnder interferometer; where i=1, 2 or 3.
Further, a first coupling waveguide (i 21) and a fifth coupling waveguide (i 25) in the ith Mach-Zehnder interferometer form a first directional coupler (i 41), a second coupling waveguide (i 22) and a sixth coupling waveguide (i 26) form a second directional coupler (i 42), a third coupling waveguide (i 23) and a seventh coupling waveguide (i 27) form a third directional coupler (i 43), and a fourth coupling waveguide (i 24) and an eighth coupling waveguide (i 28) form a fourth directional coupler (i 43). The waveguides in the directional coupler all form a concentric arc structure.
In the invention, an optical signal is input by an input waveguide (1), and part of energy is coupled to a coupling waveguide (125) after passing through a directional coupler (141); an optical signal in the coupling waveguide (121) enters the phase shift waveguide (131) through the connection waveguide (1102), and an optical signal in the coupling waveguide (125) enters the phase shift waveguide (134) through the connection waveguide (1110); the two paths of optical signals enter the directional coupler (142) through the connecting waveguide (1103) and the connecting waveguide (1111) respectively, and as the two paths of signals have specific phase difference after passing through the phase shift waveguide, the two paths of signals interfere at the directional coupler (142), the wavelength coupling which meets the interference constructive condition is enhanced, and the wavelength coupling which meets the interference destructive condition is suppressed; after interference, the output two paths of signals pass through a phase shift waveguide (132) and a phase shift waveguide (135), and second interference occurs at a directional coupler (143); then, third interference occurs at the directional coupler (144) through the phase shift waveguide (133) and the phase shift waveguide (136); under the action of multiple phase shifts and interference, optical signals of 1271nm and 1311nm wavelength components in the output signals are output by a connecting waveguide (1180), and optical signals of 1291nm and 1331nm wavelength components are output by a connecting waveguide (1116); optical signals of wavelength components 1271nm and 1311nm enter a connecting waveguide (2101) in the second Mach-Zehnder interferometer (II) through a cascade waveguide (2); through a similar process as in the first mach-zehnder interferometer (I), an optical signal of a wavelength component of 1271nm is output from the output waveguide (5) through the connection waveguide (2116), and an optical signal of a wavelength component of 1311nm is output from the output waveguide (4) through the connection waveguide (2108); similarly, optical signals of 1291nm and 1331nm wavelength components enter the connecting waveguide (3101) in the third Mach-Zehnder interferometer (III) through the cascade waveguide (3); through a similar process to that in the first mach-zehnder interference (I), an optical signal of a 1291nm wavelength component is output from the output waveguide (7) through the connection waveguide (3116), and an optical signal of a 1311nm wavelength component is output from the output waveguide (6) through the connection waveguide (3108). The directional couplers are all formed by bent waveguides, and the light splitting proportion of each directional coupler is basically kept unchanged in a wide spectrum range, so that the optical signals output by each output waveguide have low loss and low crosstalk.
The invention has the beneficial effects that:
(1) The optical splitter based on the curved waveguide directional coupler can maintain a basically constant splitting ratio in a wide spectral range, so that crosstalk of output signals of the Mach-Zehnder interferometer is effectively reduced.
(2) By using a curved waveguide directional coupler, the coupling of optical signals can be accomplished in a short distance, thereby effectively reducing the device size.
(3) By adopting the curved waveguide directional coupler, the processing tolerance of the beam splitter can be effectively improved, thereby reducing the processing cost of the device.
(4) The Mach-Zehnder interferometer with multiple interferometers is adopted, so that the output signal presents flat passband characteristics.
Drawings
FIG. 1 shows a schematic diagram of the structure of the present invention;
in the figure: I. the first Mach-Zehnder interferometer, the second Mach-Zehnder interferometer, the third Mach-Zehnder interferometer, the first cascade waveguide, the second Mach-Zehnder interferometer, the third Mach-Zehnder interferometer, the first Mach-Zehnder interferometer, the second Mach-Zehnder interferometer, the third Mach-Zehnder interferometer, the first mach-Zehnder interferometer, the input waveguide, the first, the third Mach-Ze.
FIG. 2 is a schematic diagram of the first Mach-Zehnder interferometer (I) structure;
in the figure: 1101. first connecting waveguides, …,11i, i-th connecting waveguides, …,1116, sixteenth connecting waveguides, 121, first coupling waveguides, …,12i, i-th coupling waveguides, …,128, eighth coupling waveguides, 131, first phase shifting waveguides, … 13i, i-th phase shifting waveguides, …,136, sixth phase shifting waveguides, 141, first directional couplers, …,14i, i-th directional couplers, …,144, fourth directional couplers.
FIG. 3 is a schematic diagram of the second Mach-Zehnder interferometer (II);
in the figure: 2101. first connecting waveguides, …,21i, i-th connecting waveguides, …,2116, sixteenth connecting waveguides, 221, first coupling waveguides, …,22i, i-th coupling waveguides, …,228, eighth coupling waveguides, 231, first phase shifting waveguides, … i, i-th phase shifting waveguides, …,236, sixth phase shifting waveguides, 241, first directional couplers, …,24i, i-th directional couplers, …,244, fourth directional couplers.
FIG. 4 is a schematic diagram of a third Mach-Zehnder interferometer (III);
in the figure: 3101. first connecting waveguides, …,31i, i-th connecting waveguides, …,3116, sixteenth connecting waveguides, 321, first coupling waveguides, …,32i, i-th coupling waveguides, …,328, eighth coupling waveguides, 331, first phase shifting waveguides, … i, i-th phase shifting waveguides, …,336, sixth phase shifting waveguides, 341, first directional couplers, …,34i, i-th directional couplers, …,344, fourth directional couplers.
Fig. 5 outputs a waveguide transmittance simulation curve.
Detailed Description
The invention is further described below with reference to the accompanying drawings and examples of implementations of cascaded mach-zehnder interferometer type coarse wavelength division multiplexers based on curved waveguide directional couplers.
As shown in fig. 1-5, a sparse wavelength division multiplexer based on a curved directional coupler is composed of a cascade of two stages of filters, wherein the first stage of filter comprises a first mach-zehnder interferometer (I), and the second stage of filter comprises a second mach-zehnder interferometer (II) and a third mach-zehnder interferometer (III).
The input optical waveguide (1) is connected to a first connection waveguide (1101) in the first Mach-Zehnder interferometer (I). The eighth connecting waveguide (1108) and the sixteenth connecting waveguide (1116) in the first Mach-Zehnder interferometer (I) are respectively connected with the first connecting waveguide (2101) in the second Mach-Zehnder interferometer (II) and the first connecting waveguide (3101) in the third Mach-Zehnder interferometer (III) through the first cascade waveguide (2) and the second cascade waveguide (3). An eighth connecting waveguide (2108) and a sixteenth connecting waveguide (2116) in the second Mach-Zehnder interferometer (II) are connected to the first output waveguide (4) and the second output waveguide (5), respectively. An eighth connecting waveguide (3108) and a sixteenth connecting waveguide (3116) in the third mach-zehnder interferometer (III) are connected to the third output waveguide (6) and the fourth output waveguide (7), respectively.
As shown in fig. 2, each of the mach-zehnder interferometers is composed of sixteen connecting waveguides (first connecting waveguide, …, sixteenth connecting waveguide), eight coupling waveguides (first coupling waveguide, …, eighth coupling waveguide), and six phase shifting waveguides (first phase shifting waveguide, …, sixth phase shifting waveguide).
In the i Mach-Zehnder interferometer, a first connection waveguide (i 101), a first coupling waveguide (i 21), a second connection waveguide (i 102), a first phase shift waveguide (i 31), a third connection waveguide (i 103), a second coupling waveguide (i 22), a fourth connection waveguide (i 104), a second phase shift waveguide (i 32), a fifth connection waveguide (i 105), a third coupling waveguide (i 23), a sixth connection waveguide (i 106), a third phase shift waveguide (i 33), a seventh connection waveguide (i 107), a fourth coupling waveguide (i 24), and an eighth connection waveguide (i 108) are sequentially connected in an end-to-end manner. A ninth connection waveguide (i 109), a fifth coupling waveguide (i 25), a tenth connection waveguide (i 110), a fourth phase shift waveguide (i 34), an eleventh connection waveguide (i 111), a sixth coupling waveguide (i 26), a twelfth connection waveguide (i 112), a fifth phase shift waveguide (i 35), a thirteenth connection waveguide (i 113), a seventh coupling waveguide (i 27), a fourteenth connection waveguide (i 114), a sixth phase shift waveguide (i 36), a fifteenth connection waveguide (i 115), an eighth coupling waveguide (i 28), and a sixteenth connection waveguide (i 116) in the i mach-zehnder interferometer; where i=1, 2 or 3.
Further, a first coupling waveguide (i 21) and a fifth coupling waveguide (i 25) in the ith Mach-Zehnder interferometer form a first directional coupler (i 41), a second coupling waveguide (i 22) and a sixth coupling waveguide (i 26) form a second directional coupler (i 42), a third coupling waveguide (i 23) and a seventh coupling waveguide (i 27) form a third directional coupler (i 43), and a fourth coupling waveguide (i 24) and an eighth coupling waveguide (i 28) form a fourth directional coupler (i 43). The waveguides in the directional coupler all form a concentric arc structure.
In the invention, an optical signal is input by an input waveguide (1), and part of energy is coupled to a coupling waveguide (125) after passing through a directional coupler (141); an optical signal in the coupling waveguide (121) enters the phase shift waveguide (131) through the connection waveguide (1102), and an optical signal in the coupling waveguide (125) enters the phase shift waveguide (134) through the connection waveguide (1110); the two paths of optical signals enter the directional coupler (142) through the connecting waveguide (1103) and the connecting waveguide (1111) respectively, and as the two paths of signals have specific phase difference after passing through the phase shift waveguide, the two paths of signals interfere at the directional coupler (142), the wavelength coupling which meets the interference constructive condition is enhanced, and the wavelength coupling which meets the interference destructive condition is suppressed; after interference, the output two paths of signals pass through a phase shift waveguide (132) and a phase shift waveguide (135), and second interference occurs at a directional coupler (143); then, third interference occurs at the directional coupler (144) through the phase shift waveguide (133) and the phase shift waveguide (136); under the action of multiple phase shifts and interference, optical signals of 1271nm and 1311nm wavelength components in the output signals are output by a connecting waveguide (1180), and optical signals of 1291nm and 1331nm wavelength components are output by a connecting waveguide (1116); optical signals of wavelength components 1271nm and 1311nm enter a connecting waveguide (2101) in the second Mach-Zehnder interferometer (II) through a cascade waveguide (2); through a similar process as in the first mach-zehnder interferometer (I), an optical signal of a wavelength component of 1271nm is output from the output waveguide (5) through the connection waveguide (2116), and an optical signal of a wavelength component of 1311nm is output from the output waveguide (4) through the connection waveguide (2108); similarly, optical signals of 1291nm and 1331nm wavelength components enter the connecting waveguide (3101) in the third Mach-Zehnder interferometer (III) through the cascade waveguide (3); through a similar process to that in the first mach-zehnder interference (I), an optical signal of a 1291nm wavelength component is output from the output waveguide (7) through the connection waveguide (3116), and an optical signal of a 1311nm wavelength component is output from the output waveguide (6) through the connection waveguide (3108). The directional couplers are all formed by bent waveguides, and the light splitting proportion of each directional coupler is basically kept unchanged in a wide spectrum range, so that the optical signals output by each output waveguide have low loss and low crosstalk.
A silicon nanowire waveguide based on a silicon insulator (Silicon on Insulator, SOI) material is selected, a core layer of the silicon nanowire waveguide is made of a silicon material, the thickness is 220nm, and the refractive index is 3.46; the lower cladding is a silicon dioxide insulating layer with the thickness of 2 mu m, and the refractive index is 1.45; the upper cladding layer is SU-8 organic layer with thickness of 1 μm, and refractive index is 1.58. In this embodiment, all waveguides have a width of 350nm, and the fundamental mode of TE polarization is transmitted in the waveguide.
The two waveguides in each directional coupler are of concentric circular arc structures, and the distance between the waveguides is 125nm. The bending radiuses of the coupling waveguides positioned on the inner circular arcs are respectively as follows: the coupling waveguides 121, 212, 312 have a radius of 20.5 μm, the coupling waveguides 122, 222, 322 have a radius of 15 μm, the coupling waveguides 123, 223, 323 have a radius of 15 μm, and the coupling waveguides 124, 224, 324 have a radius of 11 μm. The opening angles of the coupling waveguides positioned in the inner circular arc are respectively as follows: the opening angles of the coupling waveguides 121, 212 and 312 are 22.5 degrees, the opening angles of the coupling waveguides 122, 222 and 322 are 31.5 degrees, the opening angles of the coupling waveguides 123, 223 and 323 are 31.5 degrees, and the opening angles of the coupling waveguides 124, 224 and 324 are 40.5 degrees. The directional coupler has a substantially constant spectral ratio in a wide spectral range, wherein the spectral ratios of the directional couplers 141, 241, 341 are 50:50, the spectral ratios of the directional couplers 142, 242, 342 are 20:80, the spectral ratios of the directional couplers 143, 243, 343 are 20:80, and the spectral ratios of the directional couplers 144, 244, 344 are 4:96.
The length difference between the phase shift waveguide 131 and the phase shift waveguide 134 is +9.88 μm, the length difference between the phase shift waveguide 132 and the phase shift waveguide 135 is-20.25 μm, and the length difference between the phase shift waveguide 133 and the phase shift waveguide 136 is-20.75 μm; the difference in length between phase shift waveguide 231 and phase shift waveguide 234 is +5.00 μm, the difference in length between phase shift waveguide 232 and phase shift waveguide 235 is-10.49 μm, and the difference in length between phase shift waveguide 233 and phase shift waveguide 236 is-10.99 μm; the difference in length between phase shift waveguide 331 and phase shift waveguide 334 is +5.13 μm, the difference in length between phase shift waveguide 332 and phase shift waveguide 335 is-10.75 μm, and the difference in length between phase shift waveguide 333 and phase shift waveguide 336 is-11.25 μm.
The above-described embodiments are intended to illustrate the present invention, not to limit it, and any modifications and variations made thereto are within the spirit of the invention and the scope of the appended claims.
Claims (4)
1. The sparse wavelength division multiplexer based on the bending directional coupler is characterized by comprising a cascade of two stages of filters, wherein the first stage of filter comprises a first Mach-Zehnder interferometer, and the second stage of filter comprises a second Mach-Zehnder interferometer and a third Mach-Zehnder interferometer; the input optical waveguide is connected with a first connecting waveguide in the first Mach-Zehnder interferometer; an eighth connecting waveguide and a sixteenth connecting waveguide in the first Mach-Zehnder interferometer are connected with the first connecting waveguide in the second Mach-Zehnder interferometer and the first connecting waveguide in the third Mach-Zehnder interferometer through a first cascade waveguide and a second cascade waveguide respectively; an eighth connecting waveguide and a sixteenth connecting waveguide in the second Mach-Zehnder interferometer are respectively connected with the first output waveguide and the second output waveguide; an eighth connecting waveguide and a sixteenth connecting waveguide in the third Mach-Zehnder interferometer are respectively connected with a third output waveguide and a fourth output waveguide;
the Mach-Zehnder interferometers are composed of sixteen connecting waveguides, eight coupling waveguides and six phase shift waveguides;
a first connecting waveguide, a first coupling waveguide, a second connecting waveguide, a first phase shift waveguide, a third connecting waveguide, a second coupling waveguide, a fourth connecting waveguide, a second phase shift waveguide, a fifth connecting waveguide, a third coupling waveguide, a sixth connecting waveguide, a third phase shift waveguide, a seventh connecting waveguide, a fourth coupling waveguide and an eighth connecting waveguide in the i Mach-Zehnder interferometer are connected in sequence; a ninth connection waveguide, a fifth coupling waveguide, a tenth connection waveguide, a fourth phase shift waveguide, an eleventh connection waveguide, a sixth coupling waveguide, a twelfth connection waveguide, a fifth phase shift waveguide, a thirteenth connection waveguide, a seventh coupling waveguide, a fourteenth connection waveguide, a sixth phase shift waveguide, a fifteenth connection waveguide, an eighth coupling waveguide, and a sixteenth connection waveguide in the i Mach-Zehnder interferometer are connected in sequence; where i=one, two or three.
2. The sparse wavelength division multiplexer based on curved directional couplers of claim 1, wherein the first coupling waveguide and the fifth coupling waveguide in the ith mach-zehnder interferometer form a first directional coupler, the second coupling waveguide and the sixth coupling waveguide form a second directional coupler, the third coupling waveguide and the seventh coupling waveguide form a third directional coupler, and the fourth coupling waveguide and the eighth coupling waveguide form a fourth directional coupler.
3. A sparse wavelength division multiplexer based on a curved directional coupler according to claim 2, wherein the directional coupler has a substantially constant split ratio over a broad spectral range; the waveguides in the directional coupler all form a concentric circular arc structure, and the distances among the waveguides are equal.
4. A sparse wavelength division multiplexer based on a curved directional coupler according to claim 2 or 3, wherein the optical signal is input by an input waveguide, and after passing through the directional coupler, part of the energy is coupled to a coupling waveguide; the optical signals in the coupling waveguide enter the phase shift waveguide through the connecting waveguide, and the optical signals in the coupling waveguide enter the phase shift waveguide through the connecting waveguide; the two paths of optical signals enter the directional coupler through the connecting waveguide and the connecting waveguide respectively, and as the two paths of signals have specific phase difference after passing through the phase shift waveguide, the two paths of signals interfere at the directional coupler, the wavelength coupling which meets the interference constructive condition is enhanced, and the wavelength coupling inhibition which meets the interference destructive condition is realized; after interference, the output two paths of signals pass through the phase shift waveguide and the phase shift waveguide, and second interference occurs at the directional coupler; then, third interference occurs at the directional coupler through the phase shift waveguide and the phase shift waveguide; under the action of multiple phase shifting and interference, optical signals of 1271nm and 1311nm wavelength components in the output signals are output by a connecting waveguide, and optical signals of 1291nm and 1331nm wavelength components are output by the connecting waveguide; optical signals of wavelength components of 1271nm and 1311nm enter a connecting waveguide in the second Mach-Zehnder interferometer through a cascade waveguide; through a process similar to that in the first Mach-Zehnder interferometer, an optical signal of a 1271nm wavelength component is output by an output waveguide through a connecting waveguide, and an optical signal of a 1311nm wavelength component is output by the output waveguide through the connecting waveguide; similarly, optical signals of 1291nm and 1331nm wavelength components enter a connecting waveguide in the third Mach-Zehnder interferometer through a cascade waveguide; through a similar process to that in the first mach-zehnder interference, an optical signal of a 1291nm wavelength component is output from the output waveguide through the connection waveguide, and an optical signal of a 1311nm wavelength component is output from the output waveguide through the connection waveguide.
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| US10498460B2 (en) * | 2018-03-02 | 2019-12-03 | Juniper Networks, Inc. | Amplified multistage demultiplexer |
| CN108828722A (en) * | 2018-07-16 | 2018-11-16 | 中国计量大学 | A kind of cascade MZI filter reducing crosstalk using secondary cascade |
| CN109541753A (en) * | 2018-12-30 | 2019-03-29 | 杭州芯耘光电科技有限公司 | A kind of Mux, Demux filter of flattening filter and its composition |
| CN113009621A (en) * | 2019-12-19 | 2021-06-22 | 中兴光电子技术有限公司 | Directional coupler and beam splitter thereof |
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