WO2024259765A1 - Arrayed waveguide grating - Google Patents

Abstract

The present disclosure provides an arrayed waveguide grating. The arrayed waveguide grating comprises: an input waveguide structure, which comprises an input waveguide and an input side planar waveguide; an output waveguide structure, which comprises an output waveguide and an output side planar waveguide; and an arrayed waveguide, which is located between the input waveguide structure and the output waveguide structure and is connected to both the input side planar waveguide and the output side planar waveguide. The input side planar waveguide and/or the output side planar waveguide comprise(s): a first waveguide component, which is provided with a gap; and two second waveguide components, which are symmetrically arranged on two opposite sides of the first waveguide component, wherein the second waveguide components are connected to the first waveguide component, and the refractive index of the second waveguide components changes periodically.

Description

Arrayed Waveguide Grating Technical Field

The present disclosure relates to the field of communication technology but is not limited to the field of communication technology, and in particular to an arrayed waveguide grating.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on the Chinese patent application with application number 202310750276.0 and application date June 21, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference.

Background Art

Filters can extract the desired frequency signal from a signal containing multiple frequency components. Filters are key components in communication systems, especially WDM optical communication systems. There are many types of optical filters, and arrayed waveguide gratings stand out among optical filters for their performance and cost advantages.

With the development of communication technology, especially coherent communication technology, optical communication systems require not only wide bandwidth but also low insertion loss indicators for optical filters. Although thermal array waveguide gratings can achieve low insertion loss indicators, the introduction of temperature control compensation devices requires additional power consumption, which in turn increases costs.

The athermal array waveguide grating does not require additional power consumption, but because the athermal array waveguide grating will introduce slit loss, the insertion loss index of the athermal array waveguide grating is significantly inferior to that of the thermal array waveguide grating. How to reduce the insertion loss index of the athermal array waveguide grating is an urgent problem to be solved in this field.

Summary of the invention

The embodiment of the present disclosure provides an arrayed waveguide grating.

The present disclosure provides an arrayed waveguide grating, wherein the arrayed waveguide grating comprises:

An input waveguide structure, comprising: an input waveguide and an input side slab waveguide;

An output waveguide structure, comprising: an output waveguide and an output side slab waveguide;

An array waveguide is located between the input waveguide structure and the output waveguide structure, and the array waveguide is connected to the input side slab waveguide and the output side slab waveguide respectively;

Wherein, the input side slab waveguide and/or the output side slab waveguide comprises:

A first waveguide component is provided with a gap;

Two second waveguide components are symmetrically arranged on two opposite sides of the first waveguide component, and the second waveguide components are connected to the first waveguide component, and the refractive index of the second waveguide components changes periodically.

The embodiment of the present disclosure arranges a first waveguide component with a slot in the input-side slab waveguide and/or output-side slab waveguide of the arrayed waveguide grating, and arranges second waveguide components with periodically changing refractive index on opposite sides of the first waveguide component, respectively. The two second waveguide components are symmetrical with respect to the first waveguide component, so that the slot loss introduced by the slot of the first waveguide component is reduced by utilizing the two second waveguide components, so that compared with other optical waveguide structures with slots, the slot loss of the arrayed waveguide grating shown in the embodiment of the present disclosure is significantly reduced, and the insertion loss value of the arrayed waveguide grating shown in the embodiment of the present disclosure after cutting is also smaller than the insertion loss value of other conventional arrayed waveguide gratings with slots. The insertion loss value of the arrayed waveguide grating shown in the embodiment of the present disclosure after cutting is even smaller than the insertion loss value of the arrayed waveguide grating before cutting (that is, the first waveguide component is not provided with a slot), so as to facilitate the definition of the insertion loss index when screening arrayed waveguide grating chips.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a structural schematic diagram 1 of an arrayed waveguide grating according to an exemplary embodiment;

FIG2 is a partial enlarged structural schematic diagram of FIG1;

FIG3 is a schematic diagram of a structure of a athermal arrayed waveguide grating according to an exemplary embodiment;

FIG4 is a second structural schematic diagram of a athermal arrayed waveguide grating according to an exemplary embodiment;

FIG5 is an enlarged schematic diagram of an input-side slab waveguide or an output-side slab waveguide according to an exemplary embodiment;

FIG6 is a schematic diagram showing a comparison of insertion losses of a PSW array waveguide grating and a conventional waveguide grating before slitting according to an exemplary embodiment;

FIG7 is a schematic diagram showing a comparison of insertion losses of a PSW array waveguide grating and a conventional waveguide grating after slitting according to an exemplary embodiment;

FIG. 8 is a schematic diagram showing a comparison of slit losses of a PSW array waveguide grating and a conventional waveguide grating according to an exemplary embodiment.

DETAILED DESCRIPTION

To make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the specific technical solution of the invention will be further described in detail below in conjunction with the drawings in the embodiments of the present disclosure. The following embodiments are used to illustrate the present disclosure, but are not used to limit the scope of the present disclosure.

The present disclosure provides an arrayed waveguide grating, as shown in FIG1 and FIG2 , FIG1 is a structural schematic diagram of an arrayed waveguide grating according to an exemplary embodiment; FIG2 is a partial enlarged structural schematic diagram of FIG1 . The arrayed waveguide grating 10 includes:

The input waveguide structure 11 comprises: an input waveguide 11a and an input side slab waveguide 11b;

The output waveguide structure 12 comprises: an output waveguide 12b and an output side slab waveguide 12a;

An array waveguide 13 is located between the input waveguide structure 11 and the output waveguide structure 12, and the array waveguide 13 is connected to the input side slab waveguide 11b and the output side slab waveguide 12a respectively;

Wherein, the input side slab waveguide 11b and/or the output side slab waveguide 12a include:

The first waveguide component 101 is provided with a gap 101a;

Two second waveguide components 102 are symmetrically arranged on two opposite sides of the first waveguide component 101, and the second waveguide components 102 are connected to the first waveguide component 101, and the refractive index of the second waveguide components 102 changes periodically.

In the embodiment of the present disclosure, the arrayed waveguide grating may include: an input waveguide structure, an output waveguide structure and an arrayed waveguide.

Here, the array waveguide is located between the input waveguide structure and the output waveguide structure, and the array waveguide The input end is connected to the output end of the input waveguide structure, and the output end of the array waveguide is connected to the input end of the output waveguide structure.

It should be noted that the array waveguide can be composed of a plurality of parallel strip waveguides, and the plurality of strip waveguides are bent and arranged in parallel, there is a length difference between two adjacent strip waveguides, and the length of each strip waveguide is different.

An input waveguide structure, comprising: an input waveguide and an input side slab waveguide;

The input end of the input side slab waveguide is connected to the input waveguide, and the output end of the input side slab waveguide is connected to the array waveguide. It can be understood that the optical signal output by the input waveguide is input into the array waveguide through the input side slab waveguide.

An output waveguide structure, comprising: an output waveguide and an output side slab waveguide;

The input end of the output side slab waveguide is connected to the array waveguide, and the output end of the output side slab waveguide is connected to the output waveguide. It can be understood that the optical signal output by the array waveguide is input into the output waveguide through the output side slab waveguide.

It should be noted that when the multiplexed optical signal transmitted in the input waveguide enters the input side slab waveguide, the multiplexed optical signal is no longer constrained in the lateral direction, and thus diffracts and expands; the laterally diffracted and expanded multiplexed optical signal is coupled into multiple strip waveguides and transmitted in the multiple strip waveguides.

Since there is a length difference between the multiple strip waveguides on the input side slab waveguide, there is a certain phase difference between the multiplexed optical signals propagating in each strip waveguide when they reach the output side slab waveguide, so that the array waveguide inputs multiple optical signals with different wavelengths and different phases to the output side slab waveguide.

Since the phase shift is related to the wavelength, the convergence imaging position of each wavelength optical signal depends on the input light wavelength. The output waveguides set at different imaging positions can decompose the optical signals of different wavelengths into the corresponding output waveguides to complete the demultiplexing function.

Conversely, the input optical signal is input from the output waveguide structure and output from the input waveguide structure, that is, the light propagation direction in the array waveguide grating is changed, and optical signals with different wavelengths can be converged into the same waveguide to complete the multiplexing function.

The input side slab waveguide and/or the output side slab waveguide comprises: a first waveguide component and two second waveguide components; the two second waveguide components are symmetrically arranged on two opposite sides of the first waveguide component.

Here, the two opposite sides of the first waveguide component may be the two ends of the first waveguide component in the light propagation direction, that is, the light propagation direction in the waveguide structure is: transmitted from one second waveguide component to the first waveguide component, and propagated from the first waveguide component to another second waveguide component.

The first waveguide component is provided with a slit; it should be noted that in order to meet the specific requirements of the arrayed waveguide grating, a slit needs to be provided on the first waveguide component. However, since the slit of the first waveguide component will generate a certain additional optical loss (i.e., slit loss) on the optical power transmitted in the first waveguide component, the loss of the arrayed waveguide grating is increased, thereby affecting the normal operation of the communication system.

The refractive index of the second waveguide component varies periodically; it can be understood that, since the refractive index of the second waveguide component varies periodically, when light propagates in the second waveguide component, the divergence angle of the light field varies periodically in at least one light field limiting direction, and the mode spot size of the light wave also varies periodically.

It should be noted that the slot loss mainly consists of the following two parts: (1) Fresnel reflection caused by the refractive index mismatch or incomplete matching of the waveguides on both sides of the slot; and (2) mode field mismatch caused by the different mode field shapes of the waveguides on both sides of the slot.

It is understandable that after cutting a conventional waveguide, the mode field of the slot part of the conventional waveguide jumps, although the waveguide mode fields of the waveguides on both sides of the slot are not mismatched at this time, but the mode field jumps. And due to the limitation of the current slot cutting process, the slot width can reach about 20um, resulting in large slot cutting loss.

In the embodiment of the present disclosure, second waveguide components with periodically changing refractive index are respectively arranged on two opposite sides of the first waveguide component, so that the mode field of the waveguide structure exhibits periodic changes; compared with the situation where the mode field increases in a jumpy manner, the waveguide structure shown in the present disclosure effectively reduces the cutting loss due to the periodic change of the mode field.

In the embodiment of the present disclosure, a first waveguide component with a slot is arranged in the input-side slab waveguide and/or output-side slab waveguide of the arrayed waveguide grating, and second waveguide components with periodically changing refractive index are arranged on opposite sides of the first waveguide component, respectively. The two second waveguide components are symmetrical with respect to the first waveguide component, so that the slot loss introduced by the slot of the first waveguide component is reduced by utilizing the two second waveguide components, so that compared with other optical waveguide structures with slots, the slot loss of the arrayed waveguide grating shown in the embodiment of the present disclosure is significantly reduced, and the insertion loss value of the arrayed waveguide grating shown in the embodiment of the present disclosure after cutting is also smaller than the insertion loss value of other conventional arrayed waveguide gratings with slots. The insertion loss value of the arrayed waveguide grating after cutting is even smaller than the insertion loss value of the arrayed waveguide grating before cutting (ie, the first waveguide component is not provided with a gap), so as to facilitate the definition of the insertion loss index when screening the arrayed waveguide grating chip.

In some embodiments, the arrayed waveguide grating further comprises:

The compensation structure is fixedly connected to the two second waveguide components respectively, and is used to drive the two second waveguide components to move relative to each other to compensate for wavelength drift caused by temperature.

In the disclosed embodiment, the arrayed waveguide grating further includes: a compensation structure;

It can be understood that since the first waveguide component of the input side slab waveguide (or the output side slab waveguide) is provided with a gap, the input side slab waveguide (or the output side slab waveguide) is divided into two parts by the gap, namely, a second waveguide component and a connected part of the first waveguide component, and another second waveguide component and a connected part of the first waveguide component.

It should be noted that due to the material of the waveguide body, especially the _SiO2 material of the planar waveguide (PLC), the refractive index of the waveguide body will change with the temperature, and the change of the refractive index will cause the center wavelength of the arrayed waveguide grating to shift. In order to make the arrayed waveguide grating work normally within the working environment temperature, it is necessary to control the center wavelength of the arrayed waveguide grating to work stably near the International Telecommunication Union-Telecommunication Standardization (ITU-T) wavelength.

In the disclosed embodiment, a gap (i.e., a first waveguide component) may be provided in the input waveguide structure and/or the output waveguide structure of the array waveguide grating, and the compensation structure may be fixedly connected to two second waveguide components on both sides of the first waveguide component respectively; here, the fixed connection method includes but is not limited to bonding, welding, screwing, etc.

When the temperature changes, the length of the compensation structure also changes (i.e., there is a phenomenon of thermal expansion and contraction), so that the compensation structure drives the two second waveguide components to move relative to each other, thereby compensating for the center wavelength drift of the array waveguide grating caused by temperature changes.

It should be noted that the specific structure of the compensation structure can be set according to actual needs. For example, the compensation structure can be a compensation structure based on a single drive rod, or the compensation structure can be a compensation structure based on a double drive rod. The embodiments of the present disclosure are not limited to this.

For example, as shown in FIG3 , FIG3 is a schematic diagram of a structure of an athermal arrayed waveguide grating according to an exemplary embodiment. The compensation structure may include: a first driving rod 201, a second driving rod 202 and the stress plate 203, and the thermal expansion coefficients of the materials of the first driving rod 201 and the second driving rod 202 are both greater than the thermal expansion coefficient of the material of the stress plate 203. The stress plate 203 includes a first sub-section 203a and a second sub-section 203b; wherein the two second waveguide components are respectively fixedly connected to the two sub-sections of the stress plate 203. The two ends of the first driving rod 201 are respectively connected to a force-bearing portion in the first sub-section 203a and a second sub-section 203b; the second driving rod 202 acts on another force-bearing portion in the first sub-section 203a.

When the temperature changes, the length of the first driving rod is extended and contracted, so that the two sub-parts of the stress plate are relatively translated and/or rotated, thereby forming temperature compensation. And by using the first driving rod and the second driving rod acting on different positions of the application plate, the distance and/or angle between the two force-bearing parts in the stress plate are changed, forming elastic deformation.

As another example, as shown in FIG4 , FIG4 is a second structural schematic diagram of a heatless array waveguide grating according to an exemplary embodiment. The compensation structure may include two drive rods with the same thermal expansion coefficient but different lengths, and the two ends of one drive rod 301 (i.e., the first drive rod) are respectively connected to the two second waveguide components; one end of the other drive rod 302 (i.e., the second drive rod) is connected to a second waveguide component, and the other end is detachably in contact with a force-bearing end face, and the position of the force-bearing end face and the first drive rod end face on the other second waveguide component is relatively fixed.

When the temperature changes, the two second waveguide components are driven to move relative to each other by the first driving rod, and the elastic deformation of the first driving rod is changed by using the deformation amount of the second driving rod that is different from the first driving rod, so that the two second waveguide components are driven to have different relative displacements in different temperature ranges.

In some embodiments, the second waveguide assembly comprises:

A plurality of connected waveguide units, each waveguide unit having a first region and a second region, the refractive index of the first region being different from the refractive index of the second region;

The first regions and the second regions in a plurality of waveguide units are arranged alternately.

In the embodiment of the present disclosure, the second waveguide component includes: a plurality of waveguide units, and the plurality of waveguide units are connected in sequence. It should be noted that the plurality of waveguide units have the same width.

Each waveguide unit has a first region and a second region, and the first region and the second region are two adjacent regions in the waveguide unit.

The refractive index of the first region in the waveguide unit is different from the refractive index of the second region.

It can be understood that the refractive indexes of the first regions within the plurality of waveguide units are the same, and the refractive indexes of the second regions within the plurality of waveguide units are the same.

The first regions and the second regions in the plurality of waveguide units are arranged alternately and at intervals. It can be understood that the first regions and the second regions in two adjacent waveguide units are arranged adjacently.

Since the refractive indexes of the first regions in different waveguide units are the same, the refractive indexes of the second regions in different waveguide units are the same, and the refractive index of the first region is different from the refractive index of the second region; by arranging the first regions and the second regions in a plurality of waveguide units alternately and at intervals, the refractive index of the second waveguide component composed of a plurality of waveguide units presents a periodic change along the light propagation direction in the second waveguide component; thereby, when light propagates in the second waveguide component, in at least one light field limiting direction, the divergence angle of the light field presents a periodic change, and the mode spot size of the light wave presents a periodic change; thereby reducing the slit loss of the arrayed waveguide grating.

In some embodiments, the duty cycles of the plurality of waveguide units in the second waveguide assembly are different;

The duty cycle is used to describe the ratio between the width of the first region or the second region in the waveguide unit and the width of the waveguide unit.

In the embodiment of the present disclosure, the duty cycle of the waveguide unit is the ratio between the area width of the first area or the second area within the waveguide unit and the width of the waveguide unit; here, the width of the waveguide unit depends on the sum of the area widths of the first area and the second area.

It can be understood that since the widths of the multiple waveguide units are the same, the duty cycles of the multiple waveguide units in the second waveguide component are different, that is, the area widths of the first areas of the multiple waveguide units in the second waveguide component are different, or the area widths of the second areas of the multiple waveguide units in the second waveguide component are different.

It should be noted that the embodiment of the present disclosure utilizes multiple waveguide units with different duty cycles to form a second waveguide component, so that when light propagates in the second waveguide component, the divergence angle of the light field and the mode spot size of the light wave change with the change of the duty cycle of the multiple waveguide units through the change of the duty cycle between the multiple waveguide units in the second waveguide component.

In some embodiments, the duty cycle of the plurality of waveguide units in the second waveguide assembly presents an increasing or decreasing trend in the light propagation direction of the waveguide units.

In the embodiment of the present disclosure, the second waveguide assembly includes a plurality of connected waveguide units, and a plurality of The duty cycle of the waveguide unit presents a unidirectional variation trend in the light propagation direction of the second waveguide component.

It can be understood that the duty cycle of the plurality of waveguide units presents an increasing or decreasing trend in the light propagation direction of the second waveguide assembly.

In one embodiment, the duty cycles of the plurality of waveguide units in the two second waveguide components have opposite changing trends in the light propagation directions of the waveguide units.

It should be noted that since the two second waveguide components are symmetrical with respect to the first waveguide component, if the duty cycle of the multiple waveguide units in one second waveguide component shows a decreasing trend in the light propagation direction of the second waveguide component, then the duty cycle of the multiple waveguide units in the other second waveguide component shows an increasing trend in the light propagation direction of the second waveguide component.

In some embodiments, the duty cycle of the waveguide unit is positively correlated with the distance between the waveguide unit and the first waveguide assembly;

The duty cycle is a duty cycle corresponding to the first region, and the refractive index of the first region is higher than the refractive index of the second region.

In the embodiment of the present disclosure, the refractive index of the first region of the waveguide unit is higher than that of the second region; that is, the first region may be a high refractive index region within the waveguide unit, and the second region may be a low refractive index region within the waveguide unit.

The ratio between the width of the first region and the width of the waveguide unit can be determined as the duty cycle, and the duty cycle can be used to describe the proportion occupied by the high refractive index region in each waveguide unit.

The duty ratios of the plurality of waveguide units in each second waveguide assembly present a unidirectional variation trend in the light propagation direction of the waveguide units.

The duty cycle of the waveguide unit can be determined based on the distance between the waveguide unit and the first waveguide component; here, the duty cycle of the waveguide unit is positively correlated with the distance between the waveguide unit and the first waveguide component; it can be understood that, in the second waveguide component, the duty cycle close to the first waveguide component is smaller than the duty cycle far away from the first waveguide component.

Since the second waveguide component is symmetrically arranged on two opposite sides of the first waveguide component, the duty cycle of the second waveguide component located on the input side of the first waveguide component shows a decreasing trend in the light propagation direction of the waveguide structure, that is, in the light propagation direction, the duty cycle in the second waveguide component changes from large to small. The duty cycle of the second waveguide component at the output side of the waveguide component presents an increasing trend, that is, in the light propagation direction, the duty cycle in the second waveguide component changes from small to large.

It should be noted that, when light propagates in the second waveguide component, the divergence angle of the light field and the mode spot size of the light wave change with the duty cycle of the multiple waveguide units. By making the duty cycle of the second waveguide component located on the input side of the first waveguide component present a decreasing trend, and the duty cycle of the second waveguide component located on the output side of the first waveguide component present an increasing trend, when light propagates in the waveguide structure, the divergence angle of the light field and the mode spot size of the light wave both show a trend of changing from small to large and then from large to small, so as to compensate for the slit loss of the arrayed waveguide grating.

In some embodiments, the duty cycle of the plurality of waveguide units in the second waveguide assembly varies with the change of the waveguide width of the second waveguide assembly in a preset direction;

Wherein, the preset direction is parallel to the light propagation direction in the second waveguide component.

In the embodiment of the present disclosure, since the duty cycle of the waveguide unit is the ratio between the region width of the first region and the width of the waveguide unit, the duty cycle of the waveguide unit can be adjusted by changing the width of the waveguide unit.

Since the second waveguide component is arranged in the input side slab waveguide and/or the output side slab waveguide, and the input side slab waveguide and the output side slab waveguide are multimode waveguide components, the duty cycle of the second waveguide component can only be adjusted by adjusting the waveguide width of the second waveguide component in a preset direction.

Here, the preset direction is: a direction parallel to the light propagation direction in the second waveguide component.

Exemplarily, the duty cycle of the second waveguide component may be adjusted by adjusting the lateral waveguide width of the second waveguide component.

In some embodiments, as shown in FIG2 , the first waveguide component comprises:

Waveguide body;

The slit mark 101b is disposed on the waveguide body and is used to indicate a position to be cut on the waveguide body to form the slit.

In the embodiment of the present disclosure, the first waveguide component includes: a waveguide body.

In order to facilitate cutting of the waveguide body, a cutting mark can be set on the surface of the waveguide body, and the cutting mark is used to indicate the position to be cut on the waveguide body, so that when cutting the waveguide body, Slits are cut based on the slit marks to form gaps.

In some embodiments, the waveguide body may be provided with a plurality of slit marks, and the slit position of the waveguide body may be determined by the linear positions of the plurality of slit marks.

Here, the waveguide body may be provided with at least two slit marks, and based on the straight line where the at least two slit marks are located, the slit position of the waveguide body can be more accurately located.

The shape of the cutting mark can be determined according to the cutting equipment actually used. For example, the cutting mark can be in the shape of a "one", a "cross", etc.

In some embodiments, the waveguide width of the waveguide body is determined by the slot width and slotting tolerance of the waveguide body.

In the embodiment of the present disclosure, the waveguide width of the waveguide body may depend on the slit width and slit tolerance of the waveguide body.

It should be noted that when the waveguide body is cut to form the slit, the waveguide width of the waveguide body should be determined with reference to the slit width of the slit; considering the slit tolerance, the waveguide width of the waveguide body should be determined based on the slit width of the slit and the slit tolerance.

In some embodiments, as shown in FIG5 , FIG5 is an enlarged schematic diagram of an input side slab waveguide or an output side slab waveguide according to an exemplary embodiment. The first waveguide component 101 includes:

The matching liquid 101c is filled in the gap of the waveguide body; wherein the refractive index of the matching liquid 101c is related to the refractive index of the waveguide body.

In an embodiment of the present disclosure, a first waveguide assembly includes: a matching liquid;

The matching liquid is filled in the gap of the waveguide body; it should be noted that the matching liquid has a high transmittance to the light propagating in the waveguide body; the refractive index of the matching liquid is the same as or similar to the refractive index of the waveguide body. Fresnel reflection caused by the mismatch or incomplete matching of the refractive index of the waveguide on both sides of the gap is also one of the causes of the slot loss. In order to reduce the slot loss, the Fresnel reflection can be reduced by filling the gap with a suitable matching liquid.

In some embodiments, the refractive index of the matching liquid may be determined based on the material of the waveguide body.

Exemplarily, if the waveguide body is made of planar waveguide PLC SiO ₂ material, the refractive index of the corresponding matching liquid is the same as the refractive index of the waveguide body.

As another example, if the waveguide body is made of silicon photonic material, the refractive index of the corresponding matching liquid is smaller than the refractive index of the waveguide body.

In some embodiments, the slot is close to the center of the waveguide body; wherein the insertion loss parameter of the array waveguide grating is positively correlated with the distance between the slot and the center of the waveguide body.

In the embodiment of the present disclosure, the gap may be close to the center position of the waveguide body; and the closer the gap is to the center position of the waveguide body, the smaller the insertion loss parameter of the arrayed waveguide grating; conversely, the farther the gap is from the center position of the waveguide body, the larger the insertion loss parameter of the arrayed waveguide grating.

It should be noted that since the two second waveguide components are symmetrically arranged on both sides of the first waveguide component, if the gap is located at the center of the waveguide body, the two second waveguide components are symmetrically arranged relative to the gap, thereby effectively reducing the insertion loss of the array waveguide grating after cutting.

In some embodiments, the slit mark may be set at the center of the waveguide body so as to perform cutting at the center of the waveguide body to form a slit.

Assuming that the transmission spectrum of the 40-channel array waveguide grating filter with a frequency interval of 100 GHz is required to be a flat-top type, the specific index requirements are: the 1dB net bandwidth index requirement is greater than or equal to 0.38nm, the 3dB net bandwidth index requirement is greater than or equal to 0.52nm, the adjacent crosstalk index requirement is greater than or equal to 25dB, the non-adjacent crosstalk index requirement is greater than or equal to 27dB, and the insertion loss index requirement is less than or equal to 5dB.

In order to reflect the performance difference between the input side slab waveguide and/or the output side slab waveguide shown in the embodiment of the present disclosure, the arrayed waveguide grating (abbreviated as "PSW arrayed waveguide grating") including the second waveguide component, i.e., the periodically segmented waveguide (PSW) and the conventional waveguide grating, as shown in Figures 6 and 7, Figure 6 is a schematic diagram of the insertion loss comparison between a PSW arrayed waveguide grating and a conventional waveguide grating before slitting according to an exemplary embodiment; Figure 7 is a schematic diagram of the insertion loss comparison between a PSW arrayed waveguide grating and a conventional waveguide grating after slitting according to an exemplary embodiment. As shown in Figure 6, the average of the 40 channel insertion loss indicators of the conventional unslit arrayed waveguide grating is about 4.3dB, that is, the channel insertion loss indicator of the arrayed waveguide grating chip is about 4.3dB. After the conventional unslit arrayed waveguide grating is athermal packaged and the slits are filled with matching liquid, as shown in Figure 7, the insertion loss indicator of the conventional athermal arrayed waveguide grating is about 4.9dB.

Considering the consistency of insertion loss between channels, there are some channels with insertion loss slightly greater than 5dB, and considering the fluctuation of process and test, the margin required by the insertion loss index is too small (about 0.1dB), which is not suitable for mass production. Based on this, it is necessary to develop low insertion loss athermal arrayed waveguide grating filters.

As shown in Figures 6 and 7, the waveguide array grating shown in the embodiment of the present disclosure increases the insertion loss index of the PSW waveguide array grating before slitting by about 0.3dB due to the introduction of the second waveguide component with a segmented periodic change in refractive index, that is, the insertion loss index of the PSW array waveguide grating chip before slitting is about 4.6dB, as shown in Figure 6; the PSW waveguide array grating is athermally packaged, and the slits are filled with matching liquid. The insertion loss index of the PSW array waveguide grating shown in the embodiment of the present disclosure is about 4.4dB as shown in Figure 7. It can be understood that for the insertion loss index requirement of 5dB, the insertion loss index of the PSW array waveguide grating shown in the embodiment of the present disclosure is about 4.4dB, that is, there is a large margin (about 0.6dB), and the 40 channel insertion losses of the three PSW array waveguide grating samples shown in Figure 7 all meet the insertion loss index requirements, so the array waveguide grating shown in the embodiment of the present disclosure is more suitable for large-scale production.

As shown in FIG8 , FIG8 is a schematic diagram showing a comparison of the slot loss of a PSW arrayed waveguide grating and a conventional waveguide grating according to an exemplary embodiment. The slot loss of the three PSW arrayed waveguide grating samples is about -0.2 dB, so the arrayed waveguide grating shown in the embodiment of the present disclosure can limit the insertion loss index during chip screening and is more suitable for mass production. As can be seen from FIG8 , compared with the slot loss of a conventional athermal arrayed waveguide grating (about 0.6 dB), the slot loss of the athermal arrayed waveguide grating shown in the embodiment of the present disclosure is reduced by about 0.8 dB.

Compared with the heated array waveguide grating, here, the heated array waveguide grating controls the working temperature of the array waveguide grating to be constant through a temperature control device, thereby compensating for the change of the central wavelength of the array waveguide grating with the ambient temperature. Since the heated packaging of the array waveguide grating has no additional additional damage, and the temperature-related loss is low and can be ignored, the insertion loss index of the heated array waveguide grating is similar to that of the conventional unslit array waveguide grating, that is, 4.3dB. Therefore, the insertion loss index of the athermal array waveguide grating shown in the embodiment of the present disclosure is only increased by 0.1dB compared with the conventional heated array waveguide grating, that is, the insertion loss index of the athermal array waveguide grating shown in the embodiment of the present disclosure is similar to that of the heated array waveguide grating. Therefore, the athermal array waveguide grating shown in the embodiment of the present disclosure can be replaced with existing heated array waveguide gratings and other indicators, and compared with the existing heated array waveguide grating, the athermal array waveguide grating shown in the embodiment of the present disclosure is athermal. Power consumption required.

The arrayed waveguide grating recorded in the examples of the present disclosure is only taken as an example of the embodiments described in the present disclosure, but is not limited to this. As long as it involves the arrayed waveguide grating, it is within the protection scope of the present disclosure.

It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial number of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments.

It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

The embodiment of the present disclosure arranges a first waveguide component with a slot in the input-side slab waveguide and/or output-side slab waveguide of the arrayed waveguide grating, and arranges second waveguide components with periodically changing refractive index on opposite sides of the first waveguide component, respectively. The two second waveguide components are symmetrical with respect to the first waveguide component, so that the slot loss introduced by the slot of the first waveguide component is reduced by utilizing the two second waveguide components, so that compared with other optical waveguide structures with slots, the slot loss of the arrayed waveguide grating shown in the embodiment of the present disclosure is significantly reduced, and the insertion loss value of the arrayed waveguide grating shown in the embodiment of the present disclosure after cutting is also smaller than the insertion loss value of other conventional arrayed waveguide gratings with slots. The insertion loss value of the arrayed waveguide grating shown in the embodiment of the present disclosure after cutting is even smaller than the insertion loss value of the arrayed waveguide grating before cutting (that is, the first waveguide component is not provided with a slot), so as to facilitate the definition of the insertion loss index when screening arrayed waveguide grating chips.

The above is only an embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in this disclosure, which should be included in the protection scope of this disclosure. Therefore, the protection scope of this disclosure should be based on the protection scope of the claims.

Claims (11)

An arrayed waveguide grating, wherein the arrayed waveguide grating comprises: An input waveguide structure, comprising: an input waveguide and an input side slab waveguide; An output waveguide structure, comprising: an output waveguide and an output side slab waveguide; An array waveguide is located between the input waveguide structure and the output waveguide structure, and the array waveguide is connected to the input side slab waveguide and the output side slab waveguide respectively; Wherein, the input side slab waveguide and/or the output side slab waveguide comprises: A first waveguide component is provided with a gap; Two second waveguide components are symmetrically arranged on two opposite sides of the first waveguide component, and the second waveguide components are connected to the first waveguide component, and the refractive index of the second waveguide components changes periodically. The arrayed waveguide grating according to claim 1, wherein the arrayed waveguide grating further comprises: The compensation structure is fixedly connected to the two second waveguide components respectively, and is used to drive the two second waveguide components to move relative to each other to compensate for wavelength drift caused by temperature. The arrayed waveguide grating according to claim 1 or 2, wherein the second waveguide component comprises: A plurality of connected waveguide units, each waveguide unit having a first region and a second region, the refractive index of the first region being different from the refractive index of the second region; The first regions and the second regions in a plurality of waveguide units are arranged alternately. The arrayed waveguide grating according to claim 3, wherein the duty ratios of the plurality of waveguide units in the second waveguide component are different; The duty cycle is used to describe the ratio between the width of the first region or the second region in the waveguide unit and the width of the waveguide unit. The arrayed waveguide grating according to claim 4, wherein the second waveguide component has a plurality of The duty cycle of the waveguide unit presents an increasing or decreasing trend in the light propagation direction of the waveguide unit. The arrayed waveguide grating according to claim 5, wherein the duty cycle of the waveguide unit is positively correlated with the distance between the waveguide unit and the first waveguide component; The duty cycle is a duty cycle corresponding to the first region, and the refractive index of the first region is higher than the refractive index of the second region. The arrayed waveguide grating according to any one of claims 4 to 6, wherein the duty cycle of the plurality of waveguide units in the second waveguide component varies with the change of the waveguide width of the second waveguide component in a preset direction; Wherein, the preset direction is parallel to the light propagation direction in the second waveguide component. The arrayed waveguide grating according to claim 1 or 2, wherein the first waveguide component comprises: Waveguide body; A slit mark is arranged on the waveguide body and is used to indicate a position to be cut on the waveguide body to form the slit. The arrayed waveguide grating according to claim 8, wherein the waveguide width of the waveguide body is determined by the slot width and slotting tolerance of the waveguide body. The arrayed waveguide grating according to claim 9, wherein the first waveguide component comprises: A matching liquid is filled in the gap of the waveguide body; wherein the refractive index of the matching liquid is related to the refractive index of the waveguide body. The arrayed waveguide grating according to claim 8, wherein the slot is close to the center position of the waveguide body; wherein the insertion loss parameter of the arrayed waveguide grating is positively correlated with the distance between the slot and the center position of the waveguide body.