CN118465918B - Mode interference amplitude equalizer for light-operated phased array and cascading structure - Google Patents

Abstract

The invention relates to a mode interference amplitude equalizer and a cascade structure for a light-operated phased array, wherein the mode interference amplitude equalizer comprises a single-mode input waveguide, a gradual change waveguide, a first Y-branch power distribution waveguide, a standard waveguide, a mode phase control waveguide, a Y-branch power combining waveguide, a multimode waveguide, a second Y-branch power distribution waveguide and two single-mode output waveguides. The invention solves the relevance of time delay and insertion loss and solves the problems of beam synthesis gain reduction and pointing error caused by amplitude error.

Description

A mode interference amplitude equalizer and cascade structure for optically controlled phased array

Technical Field

The present invention relates to the technical field of equalizers, and in particular to a mode interference amplitude equalizer and a cascade structure for an optically controlled phased array.

Background Art

Modern high-performance radars should meet the requirements of large scanning range, no beam deflection, wide transmission bandwidth and high array gain, so broadband large-aperture phased array radar technology has become an important direction for the development of current phased array radar technology. Traditional ordinary phased array radar is a narrow-band electronic scanning radar based on phase shifters. When performing wide-angle scanning, the signal is limited due to the aperture effect and the influence of flight time.

Compared with traditional electrical phased arrays, optically controlled beamforming networks usually use optical true delay lines to achieve microwave phase shifting, which can eliminate the influence of aperture effect and transit time under large frequency bandwidth and large instantaneous bandwidth, and achieve non-tilted beam pointing. It has the advantages of large bandwidth, low loss, and anti-electromagnetic interference. It is an important technical approach to realize ultra-wideband microwave beamforming networks. Compared with microwave photonic beam networks composed of discrete optical devices, integrated optical delay networks have significant advantages in size, weight and power consumption, which is also one of the hot spots in microwave photonics research.

For array antennas, the amplitude and phase consistency and control accuracy between units are the basis for achieving precise beam pointing and reducing synthetic gain loss. Amplitude and phase consistency include phase consistency and amplitude consistency. Phase consistency refers to the relative additional phase offset of each array unit at the same frequency point within the working bandwidth; amplitude consistency refers to the relative offset of the rated output level of each array unit at the same frequency point within the working bandwidth. For optically controlled phased arrays based on integrated optical delay networks, all on-chip time delays can be equivalent to paths, that is, , where L is the path length, is the delay time, is the speed of light, For the effective refractive index, considering that the integrated waveguide has a large insertion loss, the time delay will cause additional amplitude imbalance, which will eventually lead to synthetic gain loss and beam pointing error, especially when large-angle scanning is performed, the synthetic gain loss is greater due to the increase in delay time.

At present, the optically controlled phased array based on integrated waveguide mainly focuses on how to expand the array scale, phase control, response rate and integration in the optically controlled phased array, but there is little research on the amplitude compensation of true time delay addition.

Summary of the invention

In order to solve the above problems existing in the prior art, the present invention provides a mode interference amplitude equalizer and a cascade structure for an optically controlled phased array. The technical problem to be solved by the present invention is achieved through the following technical solutions:

The present invention provides a mode interference amplitude equalizer for an optically controlled phased array, the mode interference amplitude equalizer comprising:

A single-mode input waveguide for receiving incident light;

A gradient waveguide, the input end of which is connected to the output end of the single-mode input waveguide, and is used to feed the incident light into the first Y-branch power distribution waveguide under the condition of satisfying adiabatic approximation;

a first Y-branch power distribution waveguide, wherein an input end of the first Y-branch power distribution waveguide is connected to an output end of the gradient waveguide, and is used to evenly distribute the optical power of the incident light to the first branch and the second branch of the first Y-branch power distribution waveguide;

A standard waveguide and a mode phase control waveguide, wherein the input end of the standard waveguide is connected to the output end of the first branch of the first Y-branch power distribution waveguide, the input end of the mode phase control waveguide is connected to the output end of the second branch of the first Y-branch power distribution waveguide, and the mode phase control waveguide is used to adjust the phase difference between the standard waveguide and the mode phase control waveguide according to the power distribution ratio, so that the optical power in the standard waveguide and the mode phase control waveguide is distributed according to the power distribution ratio, wherein the adjustment range of the phase difference is 0°~360°;

A Y-branch power combining waveguide, wherein the input end of the third branch of the Y-branch power combining waveguide is connected to the output end of the standard waveguide, and the input end of the fourth branch of the Y-branch power combining waveguide is connected to the output end of the mode phase control waveguide, and is used to couple the light in the standard waveguide and the mode phase control waveguide according to the power distribution ratio to the multimode waveguide;

A multimode waveguide, the input end of which is connected to the output end of the Y-branch power combining waveguide, for exciting a fundamental mode and/or a first-order mode according to the phase difference;

a second Y-branch power distribution waveguide, wherein the input end of the second Y-branch power distribution waveguide is connected to the output end of the multimode waveguide, and is used to obtain the optical power of the fifth branch of the second Y-branch power distribution waveguide according to the in-phase fundamental mode and the first-order mode, and to obtain the optical power of the sixth branch of the second Y-branch power distribution waveguide according to the anti-phase fundamental mode and the first-order mode;

Two single-mode output waveguides, the input ends of the two single-mode output waveguides are respectively connected to the output ends of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide, and are used to output light according to the optical power of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide.

In one embodiment of the present invention, the width of the mode phase control waveguide gradually decreases from both ends to the center and is symmetrically arranged along the center line.

In one embodiment of the present invention, the mode phase control waveguide adjusts the phase difference between the standard waveguide and the mode phase control waveguide through a thermo-optic effect or an electro-optic effect.

In one embodiment of the present invention, the phase difference between the fundamental mode and the first-order mode in the multimode waveguide is 0 or .

In one embodiment of the present invention, the length of the multimode waveguide is equal to An integer multiple of is the effective refractive index of the fundamental mode, is the effective refractive index of a fundamental mode, is the wavelength in vacuum.

In one embodiment of the present invention, the slopes of the first branch and the second branch of the first Y-branch power distribution waveguide, the third branch and the fourth branch of the Y-branch power combining waveguide, and the fifth branch and the sixth branch of the second Y-branch power distribution waveguide first gradually increase and then gradually decrease.

In one embodiment of the present invention, the angle between the input ends of the first branch and the second branch of the first Y-branch power distribution waveguide, the angle between the output ends of the third branch and the fourth branch of the Y-branch power combining waveguide, and the angle between the input ends of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide are all 3°~9°.

In one embodiment of the present invention, the width of the single-mode input waveguide, the width of the input end of the gradient waveguide, the width of the first branch and the second branch of the first Y-branch power distribution waveguide, the width of the standard waveguide, the width of the input end and the output end of the mode phase control waveguide, the width of the third branch and the fourth branch of the Y-branch power combining waveguide, the width of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide, and the width of the single-mode output waveguide are all equal;

The width of the output end of the gradient waveguide is equal to the sum of the widths of the first branch and the second branch of the first Y-branch power distribution waveguide, the width of the input end of the multimode waveguide is equal to the sum of the widths of the third branch and the fourth branch of the Y-branch power combining waveguide, and the width of the output end of the multimode waveguide is equal to the sum of the widths of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide.

In one embodiment of the present invention, the cross-sections of the single-mode input waveguide, the gradient waveguide, the first branch and the second branch of the first Y-branch power distribution waveguide, the standard waveguide, the mode phase control waveguide, the third branch and the fourth branch of the Y-branch power combining waveguide, the multimode waveguide, the fifth branch and the sixth branch of the second Y-branch power distribution waveguide and the single-mode output waveguide are all rectangular.

An embodiment of the present invention further provides an equalizer cascade structure, which includes a plurality of cascaded mode interference amplitude equalizers as described in any one of the above embodiments.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention converts from single mode to dual mode through adiabatic approximate transformation of a gradient waveguide, and after passing through the first Y-branch power distribution waveguide, modulates the relative phase of the second branch of the first Y-branch power distribution waveguide to achieve optical power distribution of the fundamental mode and the first-order mode. After passing through the Y-branch power combining waveguide, it is transmitted in the multimode waveguide. The multimode waveguide excites the fundamental mode and/or the first-order mode according to the phase difference, and then passes through the second Y-branch power distribution waveguide to complete the distribution of the corresponding optical power. Therefore, based on the existing structure of the beamforming network, the present invention realizes amplitude pre-control by adding Y branches and mode phase control waveguides, so that the mode interference amplitude equalizer can be fully compatible with the beamforming network. Compared with the traditional equalizer without amplitude and phase pre-configuration, the present invention solves the problem of the correlation between time delay and insertion loss, and solves the problem of beamforming gain reduction and pointing error caused by amplitude error.

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a mode interference amplitude equalizer for an optically controlled phased array provided in an embodiment of the present invention;

FIG2 is a schematic diagram of a structure of an equalizer cascade structure provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of transmission of optical power of a sampled mode interference amplitude equalizer according to the present invention.

DETAILED DESCRIPTION

The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

Embodiment 1

Please refer to FIG. 1 , which is a schematic diagram of the structure of a mode interference amplitude equalizer for an optically controlled phased array provided in an embodiment of the present invention. The embodiment of the present invention provides a mode interference amplitude equalizer for an optically controlled phased array, and the mode interference amplitude equalizer includes:

A single-mode input waveguide 1, used for receiving incident light;

A gradient waveguide 2, the input end of which is connected to the output end of the single-mode input waveguide 1, and is used to feed the incident light into the first Y-branch power distribution waveguide 3 under the condition of satisfying the adiabatic approximation;

A first Y-branch power distribution waveguide 3, the input end of the first Y-branch power distribution waveguide 3 is connected to the output end of the gradient waveguide 2, and is used to evenly distribute the optical power of the incident light to the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3;

A standard waveguide 4 and a mode phase control waveguide 5, wherein the input end of the standard waveguide 4 is connected to the output end of the first branch 31 of the first Y-branch power distribution waveguide 3, and the input end of the mode phase control waveguide 5 is connected to the output end of the second branch 32 of the first Y-branch power distribution waveguide 3, and the mode phase control waveguide 5 is used to adjust the phase difference between the standard waveguide 4 and the mode phase control waveguide 5 according to the power distribution ratio, so that the optical power in the standard waveguide 4 and the mode phase control waveguide 5 is distributed according to the power distribution ratio, wherein the adjustment range of the phase difference is 0°~360°;

A Y-branch power combining waveguide 6, wherein the input end of the third branch 61 of the Y-branch power combining waveguide 6 is connected to the output end of the standard waveguide 4, and the input end of the fourth branch 62 of the Y-branch power combining waveguide 6 is connected to the output end of the mode phase control waveguide 5, for coupling the light in the standard waveguide 4 and the mode phase control waveguide 5 according to the power distribution ratio to the multimode waveguide 7;

A multimode waveguide 7, the input end of the multimode waveguide 7 is connected to the output end of the Y-branch power combining waveguide 6, and is used to excite the fundamental mode and/or the first-order mode according to the phase difference;

a second Y-branch power distribution waveguide 8, the input end of the second Y-branch power distribution waveguide 8 being connected to the output end of the multimode waveguide 7, for obtaining the optical power of the fifth branch 81 of the second Y-branch power distribution waveguide 8 according to the in-phase fundamental mode and the first-order mode, and obtaining the optical power of the sixth branch 82 of the second Y-branch power distribution waveguide 8 according to the anti-phase fundamental mode and the first-order mode;

Two single-mode output waveguides 9, the input ends of the two single-mode output waveguides 9 are respectively connected to the output ends of the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8, and are used to output light according to the optical power of the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8.

In this embodiment, the single-mode input waveguide 1, the gradient waveguide 2, the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3, the standard waveguide 4, the mode phase control waveguide 5 and the third branch 61 and the fourth branch 62 of the Y-branch power combining waveguide 6 are all single-mode waveguide modes, and are all fundamental modes.

In this embodiment, the incident light is first fed into the single-mode input waveguide 1, and then the single-mode input waveguide 1 transmits the incident light to the gradient waveguide 2. In order to achieve lossless conversion from single mode to multimode, a waveguide with a gradient width (i.e., gradient waveguide 2) is used. This waveguide with a gradient width uses adiabatic approximation to achieve adiabatic approximation conversion from single mode to multimode, so that as much energy as possible is not scattered. It should be noted that the length from the short side (i.e., the input end of the gradient waveguide 2) to the long side (i.e., the output end of the gradient waveguide 2) in the gradient waveguide 2 is designed according to the adiabatic approximation, and this embodiment does not make specific restrictions on this. Preferably, the slope of the gradient waveguide 2 along the length direction is constant, and the width gradually increases from the input end to the output end. The length direction of this embodiment is the horizontal direction in Figure 1, and the width direction is the vertical direction in Figure 1.

In this embodiment, the incident light that has undergone adiabatic transformation of the gradient waveguide 2 enters the first Y-branch power distribution waveguide 3, and the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3 evenly distribute the optical power of the light output by the gradient waveguide 2, so that the optical power in the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3 is the same.

In this embodiment, the light in the first branch 31 of the first Y-branch power distribution waveguide 3 is output to the standard waveguide 4, and the light in the second branch 32 is output to the mode phase control waveguide 5. The power distribution ratio is set externally according to the demand. Since the power distribution ratio is proportional to the phase difference, the mode phase control waveguide 5 adjusts the phase value of the mode phase control waveguide 5 according to the externally set power distribution ratio, so that the phase difference between the standard waveguide 4 and the mode phase control waveguide 5 satisfies the power distribution ratio, and the optical power in the standard waveguide 4 and the mode phase control waveguide 5 is distributed according to the power distribution ratio. Here, the adjustment range of the phase difference can be 0°~360° through the adjustment of the mode phase control waveguide 5, so as to ensure that the first branch 31 and the second branch 32 can both achieve the change of the optical power from the maximum value to the minimum value.

Optionally, the width of the mode phase control waveguide 5 gradually decreases from both ends to the center, and is symmetrically arranged along the center line, and the slope of the mode phase control waveguide 5 along the length direction remains unchanged; the mode phase control waveguide 5 adjusts the phase difference between the standard waveguide 4 and the mode phase control waveguide 5 through the thermo-optic effect or the electro-optic effect, so that the adjustment range of the phase difference is 0°~360°. It should be noted that the length setting of the mode phase control waveguide 5 is based on the change of the phase difference from 0° to 360°, and this embodiment does not specifically limit this.

Preferably, the minimum length of the middle portion of the mode phase control waveguide 5 is half of the length of both ends.

In this embodiment, the output end of the standard waveguide 4 is connected to the input end of the third branch 61 of the Y-branch power combining waveguide 6, and the output end of the mode phase control waveguide 5 is connected to the input end of the fourth branch 62 of the Y-branch power combining waveguide 6, so that the light in the standard waveguide 4 and the mode phase control waveguide 5 distributed according to the power distribution ratio is coupled to the multimode waveguide 7 to achieve coherent synthesis of optical power, and the multimode waveguide 7 excites the fundamental mode and/or the first-order mode according to the adjusted phase difference. Specifically, when the phase difference is 0°, all are fundamental modes. When the phase difference is greater than 0° and less than 180°, the fundamental mode and the first-order mode exist at the same time in proportion, and the larger the phase difference, the larger the proportion of the first-order mode. When the phase difference is 180°, all are first-order modes. When the phase difference is greater than 180° and less than 360°, the fundamental mode and the first-order mode exist at the same time in proportion, and the larger the phase difference, the larger the proportion of the fundamental mode. In addition, the multimode waveguide 7 needs to be compatible with at least the fundamental mode and the first fundamental mode, and should not excite the second-order and higher-order modes.

Furthermore, two modes, namely the fundamental mode and the first-order mode, are transmitted in the multimode waveguide 7. Since the effective refractive indexes of the fundamental mode and the first-order mode are different (the effective refractive index can be obtained by simulation using Rsoft simulation software), different lengths of the multimode waveguide 7 will lead to different relative phase differences before branching using the second Y-branch power distribution waveguide 8. Therefore, different optical powers are output in the two branches of the second Y-branch power distribution waveguide 8. Assuming that the length of the multimode waveguide 7 is The effective refractive indices of the fundamental mode and the second fundamental mode are and , the optical power ratio of the fundamental mode and the first-order mode is , then the phase difference between the fundamental mode and the first-order mode in the multimode waveguide 7 is:

;

in, is the phase difference between the fundamental mode and the first-order mode in the multimode waveguide 7, is the wavelength in vacuum.

In this embodiment, the input ends of the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8 are connected to the output end of the multimode waveguide 7, and the fundamental mode and the first-order mode are set in phase in the fifth branch 81, and the fundamental mode and the first-order mode are set in anti-phase in the sixth branch 82, so the phase difference between the fundamental mode and the first-order mode in the fifth branch 81 is , the phase difference between the fundamental mode and the first-order mode in the sixth branch 82 is At this time, the electric field at port A in Figure 1 is expressed as: , the electric field at port B is expressed as: ,in, is the electric field at port A, is the electric field at port B, is the electric field strength of the single-mode input waveguide 1. Therefore, the optical power difference between port A and port B (that is, the optical power difference between the two single-mode output waveguides) is:

;

in, is the optical power difference of the two single-mode output waveguides 9.

From the above formula, it can be seen that when 0 or When , port A and port B have the maximum power distribution modulation efficiency, so the phase difference between the fundamental mode and the first-order mode in the multimode waveguide 7 is 0 or , and the fundamental mode and the first-order mode are output in equal phase in the multimode waveguide 7. From the phase difference formula, it can be seen that the length of the multimode waveguide 7 Preferably An integer multiple of , thereby eliminating the phase difference caused by mode dispersion.

Therefore, the incident light power ratio in the second Y-branch power distribution waveguide 8 is The fifth branch 81 and the sixth branch 82 output different optical powers. When is 1, in the sixth branch 82, due to the anti-phase cancellation, the light with the minimum optical power is output. When is 0 or infinite, when only the fundamental mode or the first-order mode is input, the optical power is evenly divided in the fifth branch 81 and the sixth branch 82. Therefore, by controlling the ratio of the optical power input in the fundamental mode and the first-order mode, the optical power of the fifth branch 81 and the sixth branch 82 with any output ratio from 0 to 40 dB can be achieved. Among them, the fifth branch 81 and the sixth branch 82 can be mirrored by the mode phase control waveguide 5 to match the symmetry of the beam scanning range.

Optionally, in order to enable a smooth transition, the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3, the third branch 61 and the fourth branch 62 of the Y-branch power combining waveguide 6, and the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8 are first gradually increased and then gradually decreased in the inclination direction along the length direction, and the shape of the first branch 31, the second branch 32, the third branch 61, the fourth branch 62, the fifth branch 81 and the sixth branch 82 are S-shaped, and the width of the first branch 31, the second branch 32, the third branch 61, the fourth branch 62, the fifth branch 81 and the sixth branch 82 remains unchanged from the input end to the output end.

Optionally, the angle α1 between the input ends of the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3, the angle α2 between the output ends of the third branch 61 and the fourth branch 62 of the Y-branch power combining waveguide 6, and the angle α3 between the input ends of the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8 are all 3°~9°.

Optionally, the width of the single-mode input waveguide 1, the width of the input end of the gradient waveguide 2, the width of the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3, the width of the standard waveguide 4, the width of the input end and the output end of the mode phase control waveguide 5, the width of the third branch 61 and the fourth branch 62 of the Y-branch power combining waveguide 6, the width of the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8, and the width of the single-mode output waveguide 9 are all equal;

The width of the output end of the gradient waveguide 2 is equal to the sum of the widths of the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3, the width of the input end of the multimode waveguide 7 is equal to the sum of the widths of the third branch 61 and the fourth branch 62 of the Y-branch power combining waveguide 6, and the width of the output end of the multimode waveguide 7 is equal to the sum of the widths of the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8.

Optionally, the cross-sections of the single-mode input waveguide 1, the gradient waveguide 2, the first branch 31 and the second branch 32 of the first Y-branch power distribution waveguide 3, the standard waveguide 4, the mode phase control waveguide 5, the third branch 61 and the fourth branch 62 of the Y-branch power combining waveguide 6, the multimode waveguide 7, the fifth branch 81 and the sixth branch 82 of the second Y-branch power distribution waveguide 8 and the single-mode output waveguide 9 are all rectangular.

Based on the above basic principles, for single-mode transmission, this embodiment converts from single mode to dual mode through adiabatic approximate transformation of the gradient waveguide 2, and after passing through the first Y-branch power distribution waveguide 3, modulates the relative phase of the second branch 32 of the first Y-branch power distribution waveguide 3, so as to realize the optical power distribution of the fundamental mode and the first-order mode, and after passing through the Y-branch power combining waveguide 6, it is transmitted in the multimode waveguide 7, and the length of the multimode waveguide 7 satisfies the integer multiple beat error, and then passes through the second Y-branch power distribution waveguide 8 to complete the corresponding optical power distribution. Therefore, based on the existing structure of the beamforming network, the present invention realizes the pre-control of the amplitude by adding Y branches and mode phase control waveguides, so that the mode interference amplitude equalizer can be compatible with the beamforming network. Compared with the traditional equalizer without amplitude and phase pre-configuration, it solves the problem of the correlation between time delay and insertion loss, and solves the problem of beamforming gain reduction and pointing error caused by amplitude error.

The mode interference amplitude equalizer and the power distribution network of the present invention can realize an integrated design. The input and output ends of the mode interference amplitude equalizer are both single-mode waveguides, and the output end can correspond to the input port of the time delay beam synthesis network.

The mode interference amplitude equalizer provided by the present invention has a simple structure and is easy to integrate into a beam synthesis network. According to the waveguide insertion loss and the true time delay value, optical power pre-compensation can be performed through phase adjustment to achieve precise control of amplitude and phase.

Embodiment 2

The present invention further provides an equalizer cascade structure based on the first embodiment. The equalizer cascade includes a plurality of cascaded mode interference amplitude equalizers.

The mode interference amplitude equalizer is a basic power preset unit, which can realize the control of ^2N channel powers through cascading, where N is the number of cascades. For example, please refer to Figure 2, which is an expanded schematic diagram of the 4-channel mode interference amplitude equalizer in the present invention.

Specifically, the specific usage is described by taking the equalizer cascade structure with 4 cascades as an example. (Picoseconds) Transmission delay insertion loss is approximately When the center frequency is , half wavelength is d, spatial pointing angle is θ, delay time For an equalizer cascade structure with 4 cascades, the difference between the maximum and minimum unit amplitudes is approximately The equalizer uses a step delay, and the delay of each step is , n is the step number, so the power ratio corresponding to each step is For different directivities, power balance compensation is achieved through the phase shift structure of the adjustable power divider.

3 is a schematic diagram of optical power transmission of the sampled mode interference amplitude equalizer in the present invention, which controls the power pre-configuration of the optical power in each channel by phase-adjusting the mode power distribution ratio and eliminating mode dispersion, thereby ensuring the consistency of amplitude and phase.

The present invention can realize the setting of the number of branches of amplitude equalization, that is, the number of units corresponding to the beam synthesis, by cascading multiple mode interference amplitude equalizers, and can be compatible with the scalability of the array scale. Through cascading and segmented power allocation, the optical power pre-matching design of multiple channels is realized.

In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, any modifications made without departing from the concept of the present invention should be deemed to belong to the protection scope of the present invention.

Claims (10)

1. A mode interference amplitude equalizer for a photo-controlled phased array, the mode interference amplitude equalizer comprising:

a single mode input waveguide for receiving incident light;

The input end of the graded waveguide is connected with the output end of the single-mode input waveguide and is used for feeding the incident light to the first Y-branch power distribution waveguide under the condition of meeting adiabatic approximation;

The input end of the first Y-branch power distribution waveguide is connected with the output end of the gradual change waveguide and is used for enabling the optical power of the incident light to be distributed to a first branch and a second branch of the first Y-branch power distribution waveguide evenly;

the optical power distribution device comprises a standard waveguide and a mode phase control waveguide, wherein the input end of the standard waveguide is connected with the output end of a first branch of the first Y-branch power distribution waveguide, the input end of the mode phase control waveguide is connected with the output end of a second branch of the first Y-branch power distribution waveguide, and the mode phase control waveguide is used for adjusting the phase difference between the standard waveguide and the mode phase control waveguide according to the power distribution proportion so as to enable the optical power in the standard waveguide and the mode phase control waveguide to be distributed according to the power distribution proportion, wherein the adjustment range of the phase difference is 0-360 degrees;

The input end of a third branch of the Y-branch power combining waveguide is connected with the output end of the standard waveguide, and the input end of a fourth branch of the Y-branch power combining waveguide is connected with the output end of the mode phase control waveguide and is used for coupling the optical power distributed in the standard waveguide and the mode phase control waveguide according to the power distribution proportion to the multimode waveguide;

The input end of the multimode waveguide is connected with the output end of the Y-branch power combining waveguide and is used for exciting a fundamental mode and a first-order mode according to the phase difference;

the input end of the second Y-branch power distribution waveguide is connected with the output end of the multimode waveguide, and is used for obtaining the optical power of a fifth branch of the second Y-branch power distribution waveguide according to the in-phase fundamental mode and the first-order mode, and obtaining the optical power of a sixth branch of the second Y-branch power distribution waveguide according to the reverse-phase fundamental mode and the first-order mode;

And the input ends of the two single-mode output waveguides are respectively connected with the output ends of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide, and are used for outputting light according to the optical power of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide.

2. The mode interference amplitude equalizer of claim 1, wherein the width of the mode phase control waveguide is gradually reduced from both ends to the center and symmetrically disposed along the center line.

3. The mode interference amplitude equalizer of claim 2, wherein the mode phase control waveguide adjusts a phase difference between the standard waveguide and the mode phase control waveguide by a thermo-optical effect or an electro-optical effect.

4. The mode interference amplitude equalizer of claim 1, wherein a phase difference between the fundamental mode and the first order mode in the multimode waveguide is 0 or pi.

5. The mode interference amplitude equalizer of claim 4, wherein the multimode waveguide has a length equal to an integer multiple of λ ₀/2(n₀-n₁), n ₀ is the effective refractive index of the fundamental mode, n ₁ is the effective refractive index of a fundamental mode, and λ ₀ is the wavelength in vacuum.

6. The mode interference amplitude equalizer of claim 1, wherein the slopes of the first and second branches of the first Y-branch power splitting waveguide, the third and fourth branches of the Y-branch power combining waveguide, and the fifth and sixth branches of the second Y-branch power splitting waveguide all gradually increase and then gradually decrease.

7. The mode interference amplitude equalizer of claim 1, wherein the angle between the input ends of the first and second branches of the first Y-branch power splitting waveguide, the angle between the output ends of the third and fourth branches of the Y-branch power combining waveguide, and the angle between the input ends of the fifth and sixth branches of the second Y-branch power splitting waveguide are all 3 ° to 9 °.

8. The mode interference amplitude equalizer of claim 1, wherein the width of the single-mode input waveguide, the width of the input end of the tapered waveguide, the widths of the first and second branches of the first Y-branch power splitting waveguide, the width of the standard waveguide, the widths of the input end and output end of the mode phase control waveguide, the widths of the third and fourth branches of the Y-branch power combining waveguide, the widths of the fifth and sixth branches of the second Y-branch power splitting waveguide, and the width of the single-mode output waveguide are all equal;

the width of the output end of the graded waveguide is equal to the sum of the widths of the first branch and the second branch of the first Y-branch power distribution waveguide, the width of the input end of the multimode waveguide is equal to the sum of the widths of the third branch and the fourth branch of the Y-branch power combining waveguide, and the width of the output end of the multimode waveguide is equal to the sum of the widths of the fifth branch and the sixth branch of the second Y-branch power distribution waveguide.

9. The mode interference amplitude equalizer of claim 1, wherein the cross-sections of the single-mode input waveguide, the graded waveguide, the first and second branches of the first Y-branch power splitting waveguide, the standard waveguide, the mode phase control waveguide, the third and fourth branches of the Y-branch power combining waveguide, the multimode waveguide, the fifth and sixth branches of the second Y-branch power splitting waveguide, and the single-mode output waveguide are all rectangular.

10. An equalizer cascade structure comprising a plurality of cascaded mode interference amplitude equalizers according to any one of claims 1 to 9.