CN118259514A - Phase compensation type silicon-based star 90-degree optical mixer - Google Patents
Phase compensation type silicon-based star 90-degree optical mixer Download PDFInfo
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- 230000003287 optical effect Effects 0.000 title claims abstract description 59
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Abstract
The invention provides a phase compensation type silicon-based star 90-degree optical mixer, wherein a silicon waveguide layer is configured to comprise a star junction formed by a signal light input waveguide, a local oscillation light input waveguide, a Y branch and 3 2X 2 multimode interference couplers (MMIs) and four output waveguides; the local oscillation light input waveguide is coupled with the Y branch input port, the signal light input waveguide is coupled with one input port of the bottom 2×2 multimode interference coupler, and the signal light and the local oscillation light are input into the 2×2MMI multimode interference areas at two sides through four paths of 90-degree bent waveguides, so that the signal light and the local oscillation light are mixed in the 2×2 MMIs at two sides and respectively led out to four output waveguides at two sides. The invention is based on a silicon-based waveguide and a multimode interference coupler, can compensate the phase deviation generated by four paths of 90-degree bent waveguides through a thermal phase shifter, and has the advantages of small size, low phase deviation, tunability and the like.
Description
Technical Field
The invention belongs to the field of optical communication, and particularly relates to a phase compensation type silicon-based star-shaped 90-degree optical mixer.
Background
The rapid increase in data transmission capacity places higher demands on the speed and quality of information transmitted by communication devices. Coherent optical communication systems have better spectral efficiency and receiver sensitivity, and better tolerance to amplitude spontaneous emission noise, dispersion and polarization mode dispersion than conventional communication transmission systems.
The 90-degree optical mixer is an important optical device of a coherent optical communication system, and is used for demodulating optical signals such as Quadrature Phase Shift Keying (QPSK), binary Phase Shift Keying (BPSK), and the like. Currently, 90-degree optical mixers can be divided into three categories, namely, optical fiber type, free space type and waveguide type according to implementation forms. The waveguide type 90-degree optical mixer has the characteristics of small volume, high integration level and compact structure, and gradually becomes a research hot spot. The waveguide type 90-degree optical mixer based on the structures of 4×4MMI, 2×4MMI and 2×2MMI cascade and the like, which are widely studied at present, has the defects of larger phase error and non-tunable phase. Therefore, further research and development of new waveguide-type 90-degree optical mixer technology is needed to improve phase accuracy and tuning capability to meet the higher quality communication requirements.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a phase compensation type silicon-based star 90-degree optical mixer, which is used for solving the problems of large size, high loss, large phase deviation and non-adjustable phase deviation of the prior art.
To achieve the above and other related objects, the present application provides a phase compensation type silicon-based star 90-degree optical mixer, wherein a silicon waveguide layer configuration includes a signal light input waveguide, a local oscillator light input waveguide, a star junction composed of a Y-branch and 32×2 MMIs, and four output waveguides; the input port of the coupling of local oscillation light input waveguide and Y branch, signal light input waveguide and one input port of the 2X 2MMI of bottom couple, through four way 90 degrees crooked waveguide, input signal light and local oscillation light to the multimode interference district of 2X 2MMI of both sides, make signal light and local oscillation light mix in 2X 2MMI of both sides, and draw out to the output waveguide of both sides respectively. The application provides two flexible layout structures, namely a first structure: the input light and the output light are respectively positioned at two sides of the star-shaped junction; and (2) a structure II: the input light and the output light are respectively located on the same side of the star-shaped junction.
Optionally, in the first structure, the local oscillator optical input waveguide includes: the input single-mode straight waveguide is connected with the left side port of the input cross waveguide, and crosstalk between the input local oscillation light and the output light is avoided by utilizing the cross waveguide. The right side port of the input cross waveguide is connected with the 90-degree bent waveguide through another section of input single-mode straight waveguide. The input 90-degree curved waveguide is connected with the input port of the Y-branch, and the input local oscillator is optically coupled into the input Y-branch by using the 90-degree curved waveguide. Two paths of output ports of the input Y branch are respectively connected with two paths of 90-degree bent waveguides, and the input Y branch is utilized to divide the input local oscillation light into two beams of light with equal intensity and same phase. The other ports of the two paths of input 90-degree bent waveguides are respectively connected with the upper input ports of 2×2 MMIs at two sides, and input local oscillation light is input to the multimode interference area for mixing with signal light.
Optionally, in the first structure, the signal light input waveguide includes: the input single-mode straight waveguide is connected with the left side port of the cross waveguide, and crosstalk between input signal light and output light is avoided by using the cross waveguide. The right side port of the input cross waveguide is connected with the 90-degree bent waveguide through another section of input single-mode straight waveguide. The input 90-degree bent waveguide is connected with an input port of the bottom 2×2MMI, and the input signal light is divided into two light beams with equal light intensity and 90-degree phase difference by the bottom 2×2MMI for mixing with local oscillation light. The other two paths of 90-degree bend waveguides are respectively connected with two output ports of the bottom 2×2MMI and input ports below the two sides 2×2MMI, and input signal light is input into the multimode interference area and used for mixing with local oscillation light.
Optionally, in the second structure, the local oscillator optical input waveguide includes: the input single-mode straight waveguide is connected with the 90-degree bent waveguide, and the input local oscillation light is led out to the input 90-degree bent waveguide. The input 90-degree bent waveguide is connected with the Y-branch input port, and the input local oscillator light is coupled into the input Y-branch by changing the propagation direction of the input light through the 90-degree bent waveguide. Two paths of output ports of the input Y branch are respectively connected with two paths of 90-degree bent waveguides, and input local oscillation light and the like are uniformly split into two beams by utilizing the Y branch. And the two output ports of the Y branch are connected with the upper input ports of 2X 2 MMIs at two sides through two input 90-degree bent waveguides, and input local oscillation light is input into the multimode interference area for mixing with signal light.
Optionally, in the second structure, the signal light input waveguide includes: the input single-mode straight waveguide is connected with the 90-degree bent waveguide, and the input signal light is led out to the input 90-degree bent waveguide. The other end of the input 90-degree bent waveguide is connected with an input port of a bottom 2×2MMI, and the input signal light is divided into two beams of light with equal light intensity and 90-degree phase difference by utilizing the input 2×2MMI and used for mixing with local oscillation light. The output port of the bottom 2×2MMI is connected with the lower input port of the two sides 2×2MMI through two paths of input 90-degree bent waveguides, and input signal light is input into the multimode interference area for mixing with local oscillation light.
Optionally, in the first structure, the I-path output waveguides respectively include: the output 90-degree bent waveguide is respectively connected with the multimode interference region and the bottom port of the crossed waveguide and is used for changing the propagation direction of output light. The top and bottom ports of the output cross waveguide are respectively connected with 90-degree bent waveguides, and crosstalk between the output light and the input local oscillator light as well as crosstalk between the output light and the signal light are avoided by utilizing the cross waveguide. The output 90-degree bent waveguide is connected with the top port of the crossed waveguide and the single-mode straight waveguide and is used for changing the propagation direction of output light, and the output light is transmitted in a single-mode by utilizing the single-mode straight waveguide.
Optionally, in the first structure, the Q-way output waveguides respectively include: the output curved waveguide connects the multimode interference region with the left side port of the crossover waveguide, outputs output light to the crossover waveguide, and avoids crosstalk of the output light. The left side port of the output cross waveguide is connected with the curved waveguide, the right side port is connected with the single-mode straight waveguide, the single-mode straight waveguide is used for balancing the loss of the I path and the Q path of the output light, and the single-mode straight waveguide is used for transmitting the output light in a single-mode.
Optionally, in the second structure, the I-path output waveguides respectively include: the output 90-degree bent waveguide is connected with the multimode interference region and the single-mode straight waveguide, one section of the single-mode straight waveguide is connected between the two output 90-degree bent waveguides, and the other section of the single-mode straight waveguide is connected with the 90-degree bent waveguide to output light in a single-mode.
Optionally, in the second structure, the Q-way output waveguides respectively include: the output curved waveguide is connected with the multimode interference zone and the single-mode straight waveguide, and the single-mode straight waveguide is utilized to output the output light in a single-mode.
Optionally, the signal light with phase information and the local oscillation light are mixed in the multimode interference area, and the relative phase difference of the four output ports is respectively 0 degrees, 90 degrees, 180 degrees and 270 degrees due to the self-mapping effect of the MMI. The branches with 0-degree and 180-degree output ends passing through the balance detector are called quadrature Q branches, and the branches with 90-degree and 270-degree output ends passing through the balance detector are called in-phase I branches.
Optionally, the multimode interference zone length is:
Where L π is the beat length of the two lowest order modes, and β 0 and β 1 are the propagation constants of the fundamental and first order modes of the multimode interference region.
Alternatively, the phase error of the structure is mainly derived from a 90 degree bend waveguide and a2×2MMI structure.
Optionally, the multimode interference zone has a width of 2.4 microns and the multimode interference zone has a length of 8 microns.
Optionally, the loss of the phase compensation type silicon-based star 90-degree optical mixer in the C wave band is less than 1dB.
Optionally, the phase offset of the phase offset type silicon-based star 90-degree optical mixer in the C-band is less than 3 degrees.
Alternatively, the phase compensating silicon-based star 90-degree optical mixer may adjust the phase offset introduced by the 90-degree curved waveguide by a thermal phase shifter.
As described above, the phase compensation type silicon-based star 90-degree optical mixer of the present invention has the following beneficial effects:
The invention provides a phase compensation type silicon-based star 90-degree optical mixer which is small in size, low in loss, low in phase deviation and tunable: the 90 degree optical mixing function can be implemented with a multimode interference coupler (MMI) and the phase errors produced by the four 90 degree curved waveguides can be compensated by thermal phase shifters. The phase compensation type silicon-based star 90-degree optical mixer has small size, the loss in the C wave band is less than 1dB, the phase error in the C wave band is less than 3 degrees, and the unbalance in the C wave band is less than 0.2dB, and the indexes indicate that the device can be used for binary phase shift keying signals in the C wave band without any digital calibration algorithm.
Drawings
Fig. 1 to 2 are schematic diagrams showing two structures of a phase compensation type silicon-based star 90-degree optical mixer according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of a star structure and a port description of a phase compensation type silicon-based star 90-degree optical mixer according to the present embodiment.
Fig. 4 to 6 show the phase error before and after tuning of the phase compensation type silicon-based star 90-degree optical mixer according to the present embodiment. Fig. 4 shows the phase error of the original structure of the phase compensation type silicon-based star 90-degree optical mixer according to the present embodiment, and fig. 5 shows the phase compensation type silicon-based star 90-degree optical mixer according to the present embodimentFig. 6 shows the phase error after tuning of the phase compensation type silicon-based star 90-degree optical mixer according to the present embodiment.
Fig. 7 to 9 show the common mode rejection ratio, insertion loss and imbalance curves of the phase compensation type silicon-based star 90-degree optical mixer of the present embodiment.
Description of the structural elements of FIG. 1
10 Local oscillation optical input waveguide
101 Input single mode straight waveguide
102. Input crossover waveguide
103. Input single-mode straight waveguide
104 Input 90 degree bend waveguide
105 Input Y-branch
106-Input 90-degree bend waveguide
20 Signal light input waveguide
201 Input single mode straight waveguide
202 Input crossover waveguide
203 Input single-mode straight waveguide
204 Input 90 degree bend waveguide
205 Input 90 degree bend waveguide
30 First I-way output
301 Output single-mode straight waveguide
302 Output 90 degree bend waveguide
303 Output single-mode straight waveguide
40 Second I-way output
50 First Q-way output
501 Output 90 degree bend waveguide
502 Output crossover waveguide
503 Output single mode straight waveguide
60 Second Q-way output
70 First MMI
80 Second MMI
90 Third MMI
Description of the structural elements of FIG. 2
110 Local oscillation optical input waveguide
1101 Input single mode straight waveguide
1102 Input 90 degree bend waveguide
1103 Input Y-branch
1104 Input 90 degree bend waveguide
120 Signal light input waveguide
1201 Input single mode straight waveguide
1202 Input 90 degree bend waveguide
1203 Input 90 degree bend waveguide
130 First I-way output
1301 Output 90 degree bend waveguide
1302 Output single-mode straight waveguide
1303 Output 90 degree bend waveguide
1304 Output single-mode straight waveguide
140 Second I-way output
150 First Q-way output
1501 Output curved waveguide
1502 Output single-mode straight waveguide
160 Second Q-way output
170 First MMI
180 Second MMI
190 Third MMI
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
As described in detail in the embodiments of the present invention, the cross-sectional view of the device structure is not partially enlarged to a general scale for convenience of explanation, and the schematic drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
For ease of description, spatially relative terms such as "under", "below", "beneath", "above", "upper" and the like may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that these spatially relative terms are intended to encompass other orientations of the device in use or operation in addition to the orientation depicted in the figures. Furthermore, when a layer is referred to as being "between" two layers, it can be the only layer between the two layers or one or more intervening layers may also be present.
In the context of the present application, a structure described as a first feature being "on" a second feature may include embodiments where the first and second features are formed in direct contact, as well as embodiments where additional features are formed between the first and second features, such that the first and second features may not be in direct contact.
It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings rather than the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.
As shown in fig. 1, in the first structure, the configuration of the silicon waveguide layer of the mixer includes a signal light input waveguide 20, a local oscillation light input waveguide 10, a star-shaped junction 90 composed of a Y-branch 105 and 32×2 MMIs 70, 80, 90, and four output waveguides 30, 40, 50, 60 through a photolithography process and an etching process; the local oscillator light input waveguide 10 is coupled to the Y-branch 105, the signal light input waveguide 20 is coupled to the bottom 2×2MMI180, and the signal light and the local oscillator light are input to the two-sided 2×2MMI70, 90 multimode interference regions through four-way 90-degree bent waveguides 106, 205, so that the signal light and the local oscillator light are mixed in the two-sided 2×2MMI70, 90 and respectively led out to the I-way output waveguides 30, 40 and the Q-way output waveguides 50, 60. Wherein the input light and the output light are respectively positioned at two sides of the star-shaped junction.
In the first configuration, the local oscillation optical input waveguide 10 includes: the input single-mode straight waveguide 101 is connected to the left port of the input cross waveguide 102, and crosstalk between the input local oscillation light and the output light is avoided by using the cross waveguide. The right side port of the input crossover waveguide 102 is connected by another segment of input single-mode straight waveguide 103 and 90-degree curved waveguide 104. The input 90 degree bend waveguide 104 is connected to the input port of the Y-branch 105, and the input local oscillator light is coupled into the input Y-branch using the 90 degree bend waveguide. Two output ports of the input Y-branch 105 are respectively connected with two 90-degree bent waveguides 106, and the input local oscillation light is divided into two beams of light with equal intensity and identical phase by using the input Y-branch. The other ports of the two paths of input 90-degree bent waveguides 106 are respectively connected with the upper input ports of the 2×2 MMIs 70 and 90 on the two sides, and input local oscillation light is input into the multimode interference region for mixing with signal light.
In the first configuration, the signal light input waveguide 20 includes: the input single-mode straight waveguide 201 is connected to the left port of the cross waveguide 202, and crosstalk between the input signal light and the output light is avoided by the cross waveguide. The right side port of the input crossover waveguide 202 is connected by another segment of input single-mode straight waveguide 203 and 90-degree curved waveguide 204. The input 90-degree bent waveguide 204 is connected to an input port of the bottom 2×2MMI80, and divides the input signal light into two light beams with equal light intensity and 90 degrees phase difference for mixing with the local oscillation light through the bottom 2×2MMI 80. The other two paths of input 90-degree bent waveguides 205 are respectively connected with two output ports of the bottom 2×2MMI80 and lower input ports of the two sides 2×2 MMIs 70, 90, and input signal light is input into the multimode interference region for mixing with local oscillation light.
In the first structure, the I-way output waveguides 30,40 respectively include: the output 90-degree curved waveguide 301 is connected to the multimode interference region and the bottom port of the intersecting waveguide 102, respectively, for changing the propagation direction of the output light. The top and bottom ports of the output cross waveguide 102 are respectively connected with 90-degree curved waveguides 301 and 302, and crosstalk between the output light and the input local oscillator light and signal light is avoided by using the cross waveguide. The output 90-degree curved waveguide 302 connects the top port of the cross waveguide 102 and the single-mode straight waveguide 303 for changing the propagation direction of the output light, and the output light is transmitted in a single-mode form by using the single-mode straight waveguide.
In the first structure, the Q-way output waveguides 50,60 respectively include: the output curved waveguide 501 connects the multimode interference region with the left side port of the crossing waveguide 502, and outputs the output light to the crossing waveguide 502 while avoiding crosstalk of the output light. The left side port of the output cross waveguide 502 is connected with the curved waveguide 501, the right side port is connected with the single-mode straight waveguide 503, and the single-mode straight waveguide is used for balancing the loss of the I path and the Q path of the output light, and the output light is transmitted in a single-mode.
As shown in fig. 2, in the second structure, the silicon waveguide layer of the mixer is configured to include a signal light input waveguide 120, a local oscillation light input waveguide 110, a star-shaped 90-degree optical mixer composed of a Y-branch 1103 and 32×2 MMIs 170, 180, 190, and four output waveguides 130, 140, 150, 160 by a photolithography process and an etching process; the local oscillator light input waveguide 110 is coupled to the Y branch 1103, the signal light input waveguide 120 is coupled to the bottom 2×2MMI180, and the signal light and the local oscillator light are input to the multimode interference regions of the two-sided 2×2 MMIs 170, 190 through four-way 90-degree bent waveguides 1104, 1203, so that the signal light and the local oscillator light are mixed in the two-sided 2×2 MMIs 170, 190 and are respectively led out to the I-way output waveguides 130, 140 and the Q-way output waveguides 150, 160. Wherein the input light and the output light are both located on the same side of the star-shaped junction.
In the second structure, the local oscillation optical input waveguide 110 includes: the input single-mode straight waveguide 1101 is connected to the 90-degree curved waveguide 1102, and the input local oscillation light is led out to the input 90-degree curved waveguide 1102. The input 90 degree bend waveguide 1102 is connected to the Y-branch input port, and the input local oscillator is optically coupled into the input Y-branch 1103 by changing the propagation direction of the input light using the 90 degree bend waveguide. Two output ports of the input Y branch 1103 are respectively connected with two 90-degree curved waveguides 1104, and input local oscillation light and the like are uniformly split into two beams by using the Y branch. The two output ports of the Y-branch are connected with the upper input ports of the 2X 2 MMIs 170 and 190 at the two sides through two input 90-degree bent waveguides 1104, and input local oscillation light is input into the multimode interference area for mixing with signal light.
In the second configuration, the signal light input waveguide 120 includes: the input single-mode straight waveguide 1201 is connected to the 90-degree curved waveguide 1202, and the input signal light is led out to the input 90-degree curved waveguide 1202. The other end of the input 90-degree bend waveguide 1202 is connected to the input port of the bottom 2×2MMI180, and the input signal light is split into two light beams with equal light intensity and 90-degree phase difference by using the input 2×2MMI180, and is used for mixing with local oscillation light. The output port of the bottom 2×2MMI180 is connected to the lower input port of the two-side 2×2MMI170, 190 through the two-way input 90-degree curved waveguide 1203, and inputs the input signal light into the multimode interference region for mixing with the local oscillation light.
In the second structure, the I-way output waveguides 130 and 140 respectively include: the output 90-degree curved waveguide 1301 is connected to the multimode interference region and the single-mode straight waveguide 1302, one section of the single-mode straight waveguide 1302 is connected between the two output 90-degree curved waveguides 1301, 1303, and the other section of the single-mode straight waveguide 1304 is connected to the 90-degree curved waveguide 1303, so that output light is output in a single-mode form.
In the second structure, the Q-way output waveguides 150 and 160 respectively include: the output curved waveguide 1501 connects the multimode interference region and the single-mode straight waveguide 1502, with the single-mode straight waveguide outputting the output light in a single-mode form.
As shown in fig. 1, in the present embodiment, signal light with phase information and local oscillation light are mixed in a multimode interference region, and the relative phase differences of the four output ports are respectively 0 degrees, 90 degrees, 180 degrees and 270 degrees due to the MMI self-mapping effect. The branches with 0-degree and 180-degree output ends passing through the balance detector are called quadrature Q branches, and the branches with 90-degree and 270-degree output ends passing through the balance detector are called in-phase I branches. For example, in the present embodiment 1, the four output waveguides include a first output waveguide 50 outputting a relative phase of 0 degrees, a second output waveguide 30 outputting a relative phase of 90 degrees, a third output waveguide 40 outputting a relative phase of 270 degrees, and a fourth output waveguide 60 outputting a relative phase of 180 degrees.
As shown in fig. 2, in the present embodiment, signal light with phase information and local oscillation light are mixed in a multimode interference region, and the relative phase differences of the four output ports are respectively 0 degrees, 90 degrees, 180 degrees and 270 degrees due to the MMI self-mapping effect. The branches with 0-degree and 180-degree output ends passing through the balance detector are called quadrature Q branches, and the branches with 90-degree and 270-degree output ends passing through the balance detector are called in-phase I branches. For example, in the present embodiment 2, the four output waveguides include a first output waveguide 150 outputting a relative phase of 0 degrees, a second output waveguide 130 outputting a relative phase of 90 degrees, a third output waveguide 140 outputting a relative phase of 270 degrees, and a fourth output waveguide 160 outputting a relative phase of 180 degrees.
The multimode interference zone length is:
Where L π is the beat length of the two lowest order modes, and β 0 and β 1 are the propagation constants of the fundamental and first order modes of the multimode interference region.
As shown in fig. 1 and 2, in the present embodiment, the phase error of the structure mainly originates from the 90 degree bend waveguide and the 2×2MMI structure.
Based on the design, the embodiment can realize the 90-degree optical mixer with low loss, low phase deviation and wide bandwidth in the C wave band by optimizing the width and the length of the MMI. In this embodiment, the multimode interference zone has a width of 2.4 microns and a length of 8 microns.
Fig. 4 to 6 show the phase error before and after tuning of the phase compensation type silicon-based star 90-degree optical mixer according to the present embodiment. Fig. 4 shows that the phase error is small in the original configuration. FIG. 5 shows the changeAfter that, the phase deviation between CH1-CH3 and CH1-CH4 becomes larger, indicating that the orthogonality of the 90 degree optical mixer is degraded. Fig. 6 is a phase error of the tuned structure, and it can be seen that the tuned result is substantially identical to the original result, indicating the effectiveness of tuning.
Fig. 7 to 9 show the common mode rejection ratio, insertion loss and imbalance curves of the phase compensation type silicon-based star 90-degree optical mixer of the present embodiment. As can be seen from FIGS. 7 to 9, the common mode rejection ratio of the phase compensation type silicon-based star 90-degree optical mixer in the C band is better than-30 dB, the insertion loss is about 0.5dB, and the unbalance is less than 0.2dB.
As described above, the phase compensation type silicon-based star 90-degree optical mixer of the present invention has the following beneficial effects:
The invention provides a phase compensation type silicon-based star 90-degree optical mixer which is small in size, low in loss, low in phase deviation and tunable. The present invention can implement a 90 degree optical mixing function using a multimode interference coupler (MMI) and can adjust a phase error generated by a 90 degree curved waveguide through a thermal phase shifter. The phase compensation type silicon-based star 90-degree optical mixer designed by the invention has the advantages that the loss of a C wave band is less than 1dB, the phase error of the C wave band is less than 3 degrees, the unbalance of the C wave band is less than 0.2dB, and the indexes indicate that the device can be used for binary phase shift keying signals in the C wave band without any digital calibration algorithm.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (10)
1. The phase compensation type silicon-based star 90-degree optical mixer is characterized in that a silicon waveguide layer of the optical mixer is configured to comprise a signal light input waveguide, a local oscillation light input waveguide, a star junction formed by a Y branch and 32×2 MMIs and four output waveguides; the local oscillation light input waveguide is coupled with the Y branch input end, the signal light input waveguide is coupled with one of the input ends of the bottom 2×2MMI, the signal light and the local oscillation light are input into the multimode interference areas of the 2×2MMI at two sides through four paths of 90-degree bent waveguides, so that the signal light and the local oscillation light are mixed in the 2×2MMI at two sides and respectively led out to two I-path output waveguides and two Q-path output waveguides,
Wherein the input light and the output light are respectively positioned at two sides of the star-shaped junction.
2. The phase compensation type silicon-based star 90-degree optical mixer according to claim 1, wherein the local oscillator optical input waveguides respectively include:
The input single-mode straight waveguide is connected with the left side port of the input cross waveguide, crosstalk between input local oscillation light and output light is avoided by the cross waveguide, the right side port of the input cross waveguide is connected with the 90-degree bent waveguide through the other section of the input single-mode straight waveguide, the input 90-degree bent waveguide is connected with the input port of the Y branch, the input local oscillation light is coupled into the input Y branch by the 90-degree bent waveguide, the two output ports of the input Y branch are respectively connected with the two 90-degree bent waveguides, the input local oscillation light is divided into two light beams with equal intensity and same phase by the input Y branch, the other ports of the two input 90-degree bent waveguides are respectively connected with the upper input ports of 2X 2 MMIs at two sides, and the input local oscillation light is input into the multimode interference area for mixing with signal light.
3. The phase-compensated silicon-based star 90-degree optical mixer of claim 1, wherein: the signal light input waveguides respectively include:
The input single-mode straight waveguide is connected with the left side port of the cross waveguide, crosstalk between input signal light and output light is avoided by the cross waveguide, the right side port of the input cross waveguide is connected with the 90-degree bent waveguide through the other section of the input single-mode straight waveguide, the input 90-degree bent waveguide is connected with the input port of the bottom 2×2MMI, the input signal light is divided into two light beams with equal light intensity and 90 degrees phase difference through the bottom 2×2MMI and used for mixing with local oscillation light, the other two paths of the input 90-degree bent waveguide are respectively connected with the two output ports of the bottom 2×2MMI and the lower input ports of the two sides 2×2MMI, and the input signal light is input into the multimode interference area and used for mixing with the local oscillation light.
4. The phase-compensated silicon-based star 90-degree optical mixer of claim 1, wherein: the I-path output waveguides respectively comprise:
The output 90-degree bending waveguide is respectively connected with the multimode interference region and the bottom port of the cross waveguide and is used for changing the propagation direction of the output light, the top port and the bottom port of the output cross waveguide are respectively connected with the 90-degree bending waveguide, the cross waveguide is used for avoiding crosstalk between the output light and the input local oscillator light and crosstalk between the output light and the signal light, the output 90-degree bending waveguide is connected with the top port of the cross waveguide and the single-mode straight waveguide and is used for changing the propagation direction of the output light, and the single-mode straight waveguide is used for transmitting the output light in a single-mode.
5. The phase-compensated silicon-based star 90-degree optical mixer of claim 1, wherein: the Q-way output waveguides respectively comprise:
The output bending waveguide is connected with the multimode interference area and the left side port of the crossing waveguide, and outputs output light to the crossing waveguide, meanwhile crosstalk of the output light is avoided, the left side port of the output crossing waveguide is connected with the bending waveguide, the right side port is connected with the single-mode straight waveguide, and the single-mode straight waveguide is used for balancing loss of an I path and a Q path of the output light, and the output light is transmitted in a single-mode.
6. The phase compensation type silicon-based star 90-degree optical mixer is characterized in that a silicon waveguide layer of the mixer is configured to comprise a signal light input waveguide, a local oscillation light input waveguide, a star-shaped junction formed by a Y branch and 32×2 MMIs and four output waveguides; the local oscillation light input waveguide is connected with an input port coupled with the Y branch, the signal light input waveguide is coupled with one input end coupled with the bottom 2×2MMI, and the signal light and the local oscillation light are input into 2×2MMI multimode interference areas on two sides through four paths of 90-degree bent waveguides, so that the signal light and the local oscillation light are mixed in the 2×2MMI on two sides and respectively led out to two I-path output waveguides and two Q-path output waveguides, wherein the input light and the output light are both positioned on the same side of the star junction.
7. The phase-compensated silicon-based star 90-degree optical mixer of claim 6, wherein: the local oscillation optical input waveguides respectively include:
the input single-mode straight waveguide is connected with the 90-degree bent waveguide, the input local oscillation light is led out to the input 90-degree bent waveguide, the input 90-degree bent waveguide is connected with the Y-branch input port, the propagation direction of the input light is changed by utilizing the 90-degree bent waveguide, the input local oscillation light is coupled into the input Y-branch, two paths of output ports of the input Y-branch are respectively connected with the two paths of 90-degree bent waveguide, the input local oscillation light and the like are uniformly split into two beams by utilizing the Y-branch, and the two paths of output ports of the Y-branch are connected with the upper input ports of the 2X 2MMI at two sides through the two paths of input 90-degree bent waveguide, and the input local oscillation light is input into the multimode interference area and is used for mixing with signal light.
8. The phase-compensated silicon-based star 90-degree optical mixer of claim 6, wherein: the signal light input waveguides respectively include:
the input single-mode straight waveguide is connected with the 90-degree bent waveguide, input signal light is led out to the input 90-degree bent waveguide, the other end of the input 90-degree bent waveguide is connected with an input port of the bottom 2X 2MMI, the input signal light is divided into two beams of light with equal light intensity and 90-degree phase difference by utilizing the input 2X 2MMI and is used for mixing with local oscillation light, and an output port of the bottom 2X 2MMI is connected with an input port below the two sides of the 2X 2MMI through the two paths of input 90-degree bent waveguide and inputs the input signal light into the multimode interference area and is used for mixing with the local oscillation light.
9. The phase-compensated silicon-based star 90-degree optical mixer of claim 6, wherein: the I-path output waveguides respectively comprise:
The output 90-degree bent waveguide is connected with the multimode interference region and the single-mode straight waveguide, one section of the single-mode straight waveguide is connected between the two output 90-degree bent waveguides, and the other section of the single-mode straight waveguide is connected with the 90-degree bent waveguide to output light in a single-mode.
10. The phase-compensated silicon-based star 90-degree optical mixer of claim 6, wherein: the Q-way output waveguides respectively comprise:
The output curved waveguide is connected with the multimode interference zone and the single-mode straight waveguide, and the single-mode straight waveguide is utilized to output the output light in a single-mode.
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