CN115453687A

CN115453687A - Optical assembly and optical chip comprising same

Info

Publication number: CN115453687A
Application number: CN202211263009.2A
Authority: CN
Inventors: 陈林
Original assignee: Turing Quantum Technology Beijing Co ltd; Shanghai Turing Intelligent Computing Quantum Technology Co Ltd
Current assignee: Turing Quantum Technology Beijing Co ltd; Shanghai Turing Intelligent Computing Quantum Technology Co Ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2022-12-09

Abstract

The embodiment of the application relates to an optical assembly and an optical chip comprising the same. The optical assembly includes: a first light unit including a first waveguide; a second light unit comprising a second waveguide, the second light unit disposed adjacent to the first light unit; the optical interconnection unit comprises a third waveguide, wherein the same surface of the third waveguide is coupled with the first waveguide and the second waveguide, so that light enters the third waveguide from the first waveguide in an evanescent wave coupling mode and then enters the second waveguide in an evanescent wave coupling mode; and the surface width of the tail end of the first waveguide is gradually increased from the first width to the second width along the propagation direction of the light in the first waveguide, and the surface width of the head end of the second waveguide is gradually decreased from the third width to the fourth width along the propagation direction of the light in the second waveguide. The optical assembly and the optical chip comprising the same provided by the embodiment of the application can effectively solve the problems in the traditional technology.

Description

Optical assembly and optical chip comprising same

Technical Field

The application belongs to the technical field of optical communication, and particularly provides an optical component and an optical chip comprising the same.

Background

Miniaturization, low cost, etc. of optical chips require integration of optical components such as light sources, optical paths, detectors, etc., which can reduce coupling loss to reduce chip energy consumption, improve chip performance, etc., while also requiring low-loss integration among optical units. For coupling between the light units constituting the optical assembly, the following methods are currently used in many cases: the light emitted by the optical unit is emitted from the end face, the emergent end face of the light unit is coupled with the waveguide of another optical unit by using a certain mode spot conversion structure, for example, the light is coupled with the end face of an optical fiber, and the light is transmitted to the end face at the other end of the optical fiber along the optical fiber to be emitted and then enters the adjacent optical unit through the vertical optical fiber coupler; after light is directly emitted from the end face, light beams are focused into smaller mode spots through a lens and then are directly coupled and incident to adjacent light units from the end face, the end face coupler can be arranged on the waveguide end face to reduce alignment requirements and coupling loss, an optical isolator is usually arranged between adjacent light units to prevent light from being reflected into the light units, or a certain inclination angle is arranged on the waveguide end face to avoid the original path return of the light, in these modes, the final coupling loss is still large (generally larger than 5 dB), and the integration level is not high.

Therefore, the present application provides an optical assembly and an optical chip including the same.

Disclosure of Invention

The present application is made to solve the above problems, and an object of the present application is to provide an optical module and an optical chip to realize low loss optical interconnection between optical units.

The present application provides an optical assembly comprising: a first light unit including a first waveguide; a second light unit comprising a second waveguide, the second light unit disposed adjacent to the first light unit; the optical interconnection unit comprises a third waveguide, wherein the same surface of the third waveguide is coupled with the first waveguide and the second waveguide, so that light enters the third waveguide from the first waveguide in an evanescent wave coupling mode and then enters the second waveguide in an evanescent wave coupling mode; and the surface width of the tail end of the first waveguide is gradually increased from the first width to the second width along the propagation direction of the light in the first waveguide, and the surface width of the head end of the second waveguide is gradually decreased from the third width to the fourth width along the propagation direction of the light in the second waveguide.

According to another embodiment of the application, the first optical unit is a laser and the second optical unit is a passive optical device.

According to another embodiment of the present application, the first waveguide is an indium gallium arsenic phosphorous waveguide, the second waveguide is a lithium niobate waveguide, and the third waveguide is a silicon waveguide.

According to another embodiment of the present application, the optical assembly further includes a dielectric layer between the third waveguide and at least one of the first waveguide and the second waveguide.

According to another embodiment of the present application, at least one of the first waveguide, the second waveguide, and the third waveguide comprises a waveguide core layer and/or a cladding layer located outside the waveguide core layer.

According to another embodiment of the present application, the optical assembly further includes a substrate, and the optical interconnect unit is positioned on the substrate.

According to another embodiment of the present application, the optical interconnect unit includes a third waveguide array composed of a plurality of third waveguides.

According to another embodiment of the present application, at least one of the first light unit and the second light unit further comprises a height adjustment stage to adjust a height difference between the first light unit and the second light unit.

Another embodiment of the present application further provides an optical chip, which includes a plurality of the optical assemblies described above.

Still other embodiments of the present application provide an optical assembly, comprising: a plurality of first light units including a first waveguide; a plurality of second light units comprising second waveguides and disposed adjacent to the first light units; and a plurality of optical interconnection units, each optical interconnection unit comprising a third waveguide array, wherein the same surface of the third waveguide is coupled with the first waveguide and the second waveguide, so that light enters the third waveguide from the first waveguide in an evanescent coupling manner, and then enters the second waveguide in an evanescent coupling manner; the surface width of the tail end of the first waveguide is gradually increased from the first width to the second width along the propagation direction of the light in the first waveguide, and the surface width of the head end of the second waveguide is gradually decreased from the third width to the fourth width along the propagation direction of the light in the second waveguide; and the adjacent first light unit and the second light unit are coupled by the optical interconnection unit.

The optical component and the optical chip comprising the same can integrate the optical units respectively prepared in addition (for example, through bonding) by using the independently prepared optical interconnection units, can realize smaller coupling loss and larger alignment tolerance while ensuring that each optical unit respectively uses respective mature process to have higher yield, can obviously improve the overall performance and yield of final products, and reduce the product cost.

Drawings

Fig. 1 and 2 are side and top views of an optical assembly 100 according to some embodiments of the present application.

FIG. 3 is a schematic surface view of an optical assembly 100 according to other embodiments of the present application.

Fig. 4 is a schematic structural diagram of a second optical assembly 200 according to yet another embodiment of the present application.

Fig. 5 and 6 are side views of an optical assembly 100 according to still further embodiments of the present application.

Detailed Description

In order to make the technical means, the technical features, the technical objectives and the functions of the present disclosure easily understood, the optical assembly and the optical chip including the optical assembly provided by the present disclosure are specifically described below with reference to the embodiments and the accompanying drawings.

Embodiments of the present application will be described in detail below. Throughout the specification, the same or similar components and components having the same or similar functions are denoted by like reference numerals. The embodiments described herein with respect to the figures are illustrative in nature, are diagrammatic in nature, and are used to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.

As used herein, the terms "substantially", "substantially" and "about" are used to describe and illustrate minor variations. When used in conjunction with an event or circumstance, the terms can refer to instances where the event or circumstance occurs precisely as well as instances where the event or circumstance occurs in close proximity. For example, when used in conjunction with numerical values, the terms can refer to a range of variation of less than or equal to ± 10% of the stated numerical value, such as less than or equal to ± 5%, less than or equal to ± 4%, less than or equal to ± 3%, less than or equal to ± 2%, less than or equal to ± 1%, less than or equal to ± 0.5%, less than or equal to ± 0.1%, or less than or equal to ± 0.05%. For example, two numerical values are considered to be "substantially" identical if the difference between the two numerical values is less than or equal to ± 10% (e.g., less than or equal to ± 5%, less than or equal to ± 4%, less than or equal to ± 3%, less than or equal to ± 2%, less than or equal to ± 1%, less than or equal to ± 0.5%, less than or equal to ± 0.1%, or less than or equal to ± 0.05%) of the mean of the values.

In the embodiments of the present application, unless otherwise specified or limited, relative terms such as: the terms "vertical," "lateral," "upper," "lower," and derivatives thereof (e.g., "upper surface," etc.) should be construed to refer to the orientation as then described in the discussion or as shown in the drawings. These relative terms are for convenience of description only and do not require that the present application be constructed or operated in a particular orientation.

In addition, for convenience of description, "first," "second," and the like may be used herein to distinguish one element or series of elements from another. "first," "second," etc. are not intended to describe corresponding components.

As shown in fig. 1, the upper portion is a side view of the optical assembly 100, and the lower portion is a top view of the optical assembly 100. The present application provides an optical assembly 100 comprising: a first light unit 101 comprising a first waveguide 110; a second light unit 102 comprising a second waveguide 120, the second light unit 102 being disposed adjacent to the first light unit 101; and an optical interconnection unit 103 including a third waveguide 130, wherein the same surface of the third waveguide 130 (e.g., a lower surface of the third waveguide 130 shown in fig. 1) is coupled to the first waveguide 110 and the second waveguide 120, so that light enters the third waveguide 130 from the first waveguide 110 by evanescent coupling and then enters the second waveguide 120 by evanescent coupling.

Evanescent coupling occurs when two waveguides are in close proximity, e.g., on the order of the wavelength of the light being transmitted or less, and the evanescent waves of the two waveguide modes (the optical field outside the waveguide core) overlap sufficiently, such that light is transmitted from one waveguide to the other. The third waveguide 130 may have tapered surfaces at both ends (as illustrated in the lower diagram of fig. 1) to further achieve low-loss evanescent coupling.

"coupling" in this application may be understood as optical coupling or mechanical coupling, e.g. attaching or fixing the first waveguide and the third waveguide, or merely contacting without any fixation, and it is understood that direct coupling or indirect coupling (in other words, coupling without direct contact) may be provided.

The optical unit in this application can be an active optical device and a passive optical device, and generally includes a waveguide structure, which supports light transmission along a waveguide, and can control or interact with light waves, such as routing, modulating, detecting, generating, amplifying or absorbing light, and so on.

According to some embodiments of the present application, the optical assembly further includes a dielectric layer between the third waveguide and at least one of the first waveguide and the second waveguide, for example, bonding between the waveguides may be assisted using a polymer (e.g., BCB) thin film (approximately 100nm or less), or the third waveguide may be directly bonded to at least one of the first waveguide and the second waveguide through an oxide layer having a thickness of about a few nanometers.

According to some embodiments of the present application, at least one of the first waveguide, the second waveguide, and the third waveguide comprises a waveguide core layer and/or a cladding layer located outside the waveguide core layer. Wherein the waveguide core layer may be: indium gallium arsenide phosphide (InGaAsP) waveguides, gallium arsenide (GaAs) waveguides, lithium niobate waveguides, silicon waveguides (e.g., amorphous silicon waveguides or single crystal silicon waveguides), and claddings of indium phosphide, silicon dioxide, and the like.

Generally, light is transmitted from a first waveguide to a second waveguide by end-coupling, using some spot-size conversion structure, and the like, and the final coupling loss is still large and the integration level is not high.

According to the method, the low-loss optical coupling between the optical units is realized by using the third waveguide through evanescent wave coupling, and the design of the tapered structures (Taper) at the two ends of the third waveguide enables the integration process to realize larger alignment tolerance, so that the product yield is improved.

The both ends of the third waveguide may have tapered surfaces by setting the surface width of the both ends of the third waveguide to be gradually varied as shown in the lower part of fig. 1, or setting the thickness of the both ends of the third waveguide to be gradually varied (vertical taper) as shown in the lower part of fig. 2.

FIG. 3 is a schematic surface view of an optical assembly 100 according to further embodiments of the present application.

Similar to the third waveguide with tapered surfaces at two ends, the tail end of the first waveguide and the head end of the second waveguide can be respectively designed into structures with gradually-changed surface widths so as to realize low-loss evanescent coupling. As shown in fig. 3, the surface width of the terminal end of the first waveguide 110 gradually increases from the first width 115 to the second width 116 along the direction of light propagation in the first waveguide (e.g., the Y-axis direction in fig. 3), and the surface width of the head end of the second waveguide 120 gradually decreases from the third width 126 to the fourth width 125 along the direction of light propagation in the second waveguide (e.g., the Y-axis direction in fig. 3).

As shown in fig. 3, according to other embodiments of the present disclosure, the optical interconnection unit 103 may include a third waveguide array (Nanoteeth) formed by a plurality of third waveguides 130, the tapered structure design of the third waveguides in the optical interconnection unit at two ends, and the array structure formed by the plurality of third waveguides increases alignment tolerance, which facilitates alignment between the optical interconnection unit and the optical unit located below the optical interconnection unit in the integration process, and simultaneously increases the surface width of the opposite ends of the first waveguide and the second waveguide, which also facilitates alignment between the first optical unit and the second optical unit.

In practical applications, the array structure of the plurality of third waveguides may also extend in the positive and negative directions of the X-axis as shown in fig. 3, so that the up-down alignment error does not affect the optical transmission loss. As shown in fig. 3, when the 5 third waveguides 130 located above the first waveguide and the second waveguide move more than one period 132 (the sum of the width of the middle of the third waveguide 130 and the distance between two adjacent third waveguides 130) in the X-axis direction, the coupling condition may also change periodically to return to the original state by adding the third waveguide array to the 5 third waveguides 130 above and below the X-axis, so as to avoid the influence of the up-and-down movement on the optical coupling effect, when the array period of the third waveguide 130 is significantly smaller than the width of the first waveguide 110 and the second waveguide 120, the change of the optical coupling efficiency caused by the movement in one period may be small, and when the ratio of the width of the opposite ends of the first waveguide 110 and the second waveguide 120 in the X-direction to the period of the third waveguide 130 is large (e.g. 50/2), the fluctuation of the coupling efficiency caused by the movement in one period may not exceed 0.05% (the average value of the simulated calculated efficiency is about 95%). Therefore, the positions of the optical interconnection unit and the first optical unit or the second optical unit do not need to be strictly aligned, and only the first optical unit and the second optical unit need to be aligned, so that a large alignment tolerance can be obtained, the preparation difficulty of the optical assembly is obviously reduced, and the product yield in the alignment integration process is favorably improved.

According to some embodiments of the present application, the first optical unit of the second optical assembly 200 may be an active optical device, such as a laser 201, and the second optical unit of the second optical assembly 200 may be a passive optical device 202, and in addition, the second optical unit may also be an active optical device, such as a photodetector, etc. Further, the first optical unit of the second optical subassembly 200 may also be a Semiconductor Optical Amplifier (SOA), and the second optical unit of the second optical subassembly 200 may also be a silicon waveguide chip.

As shown in fig. 4, the laser 201 may include a waveguide core (e.g., inGaAsP passive waveguide layer) and a cladding (e.g., inP cladding) outside the waveguide core, and according to the basic element division, the laser may include a gain medium (e.g., multiple quantum well MQW in fig. 4), a resonant cavity (e.g., in the form of grating in fig. 4, or FP cavity formed by two reflecting surfaces), and a pump (semiconductor lasers are generally electrically pumped by applying a voltage to an external circuit on a metal electrode as shown in fig. 4). The upper InP cladding shown in fig. 4 has a region of graded thickness, which is provided mainly for connecting two waveguide segments of different cladding thicknesses with low loss: the InP cladding layer on the left side is thicker so as to ensure that the laser mode fields are distributed symmetrically and are close to the structure of the existing laser, the laser with higher optical power is easily realized by utilizing a mature process, and the area with the thinner cladding layer on the right side is arranged so as to realize efficient evanescent wave coupling between the taper waveguide at the output end of the laser and the silicon taper array of the optical interconnection unit. By proper design in the laser cavity, it is also possible to use a thinner InP cladding at the cavity (e.g. metal electrodes distributed on the left and right sides rather than on the front and back of the substrate, so that the metal does not have to be in contact with the mode field and thus does not introduce significant metal light absorption), so that a graded thickness region is not necessary. In addition, no silica cladding can be arranged between the upper cladding InP and silicon taper array and the lithium niobate waveguide, evanescent wave coupling is easy to realize, and high-efficiency evanescent wave coupling can also be realized by a cladding or an auxiliary bonding layer which is hundreds of nanometers thick. It should be noted that the material of the laser is not limited to InP (for example, inGaAsP), but may also be other materials such as GaAs, and may even be a semiconductor laser fabricated on a heterogeneous substrate such as a silicon substrate, the material of the silicon substrate of the second optical unit and the optical interconnection unit in fig. 4 is not limited to silicon, and may also be other substrates such as lithium niobate and sapphire, and the lithium niobate waveguide of the second optical unit (passive optical chip 202) may also be a waveguide made of other materials such as silicon nitride, and at the same time, the buried oxide layer as the cladding layer may also be replaced by a cladding layer made of other low refractive index materials such as polymer.

The top view configuration of the second optical assembly 200 of fig. 4 is similar to that of fig. 3, for example, the cavity tail of the laser 201 and the head end of the lithium niobate waveguide layer of the passive optical chip may be configured as the aforementioned Taper structure to reduce the optical coupling loss. As shown in fig. 3, the width of the end of the first waveguide 110 (corresponding to the InGaAsP passive waveguide layer in fig. 4) can be gradually increased from the micrometer level at the first width (for example, at the laser resonator cavity) to a certain level, for example, the second width (for example, tens of microns or even hundreds of microns) through the tapered structure, and the length of the tapered structure needs to be more than a few millimeters (as long as the loss of the material itself is small, the loss introduced by adiabatic tapering is almost negligible). The width of the tapered structure can be kept constant, and the length is selected to be enough according to the evanescent coupling condition, such as tens or hundreds of micrometers. The method can also be used for preparing masks (vertical taper, vt) such as photoresist with proper length and gradually changed thickness by arranging proper distance between a mask plate and a wafer (wafer) in the gray scale photoetching or proximity photoetching process, and then transferring the vt into a first optical unit, such as a cladding of a waveguide section of a laser, by etching processes such as dry etching and the like, so that the thickness of the waveguide cladding is ensured to be reduced to be equal to or slightly less than the level of optical wavelength, and the efficient evanescent wave coupling between certain waveguides is realized; if the etched waveguide surface is rough, polishing may be performed using a process such as Chemical Mechanical Polishing (CMP). The width of the second waveguide 120 (e.g., a lithium niobate waveguide on the passive optical chip 202 coupled to the laser 201 in fig. 4) is also typically on the order of microns, and may also be increased by a tapered structure to a level similar to the width of the InGaAsP passive waveguide layer of the laser, and then again be a waveguide of tens of microns in width. In order to realize the effective coupling of light from the mature III-V laser into the waveguide (i.e. the third waveguide) on the optical interconnection unit, the refractive index of the material of the third waveguide (silicon taper array) should be greater than that of the cladding material (such as InP) of the traditional III-V laser, wherein the third waveguide can also be made of silicon materials such as monocrystalline silicon or amorphous silicon, so that the optical interconnection unit can be prepared on a large scale by using SOI wafer, and the evanescent coupling with low loss can be realized by the structural design of tapered surfaces at two ends of the third waveguide, such as the gradual width reduction or the gradual thickness reduction.

In fig. 4, the top-clad thinned tail waveguide of laser 201 is aligned with a silicon taper array waveguide and then interface bonded, including direct thermal bonding and bonding aided by a polymer (e.g., BCB) film. Thus, the alignment of two waveguides with widths of tens or hundreds of micrometers in the width direction can realize a very large 1dB alignment bandwidth (for example, not less than ± 10 micrometers); in the direction of the thickness of the waveguide, because the interfaces of the two optical units are bonded, the adjustment of precise alignment is not needed, and only the complete bonding and bonding of the two interfaces are ensured; in the optical axis direction of light propagation, because the transfer of light among different waveguides is realized by evanescent wave coupling, the large alignment tolerance can be realized by selecting the proper length of the connection taper waveguide; meanwhile, the loss introduced by the taper structure after design parameter optimization is almost negligible, in addition, the three optical units (the first optical unit, the second optical unit and the optical interconnection unit) which are respectively prepared can be processed and prepared by respective independent processes, high product yield is realized, and high-quality samples are selected for assembly and combination to realize final device integration. By selecting proper taper structure parameters, the coupling loss from a laser mode to a waveguide base mode such as lithium niobate or silicon nitride can be reduced to 1 dB.

For the coupling of a laser and a passive optical device (based on silicon or lithium niobate, etc.), the current scheme in the research stage is the heterogeneous growth of the laser, so-called heterogeneous integration (heterogrowth), and the laser is prepared by heterogrowing materials of III-V group, etc. on materials of silicon or silicon dioxide, etc., but due to the problems of lattice mismatch, thermal stress mismatch, etc., the current technology is not mature, the power of the obtained laser is generally lower (mW level), which is obviously lower than that of a III-V laser (hundred mW level) matched with the lattice, and the situation with higher power requirement is not applicable.

The currently available method is so-called hybrid integration (hybrid integration), in which a separately prepared laser and a passive optical device (e.g. a passive lithium niobate waveguide) are integrated by post-alignment, such as flip-chip mounting a mature III-V laser onto the passive optical device by means of a die-to-wafer. The optical coupling of the laser and the passive optical device can be achieved by end-facet coupling, but since there are high alignment requirements (i.e. alignment tolerance is small) in all three mutually perpendicular directions, and the end-facet needs to be processed to a degree suitable for coupling, it is expected that typical loss will be large, and thus the yield of the process of alignment will be low. For example, when a III-V laser is aligned and integrated with a passive lithium niobate waveguide, the optimal result loss achieved is 5.2dB, which is about 9dB from the coupling loss of the lithium niobate waveguide constituting the modulator.

Similarly, when the SOA is end-coupled with a silicon waveguide chip, a so-called Spot Size Converter (SSC) is used, the SSC on the SOA converts the laser micrometer-scale spot size to about 3 micrometers, and the SSC at the end of the silicon waveguide chip has similar mode field sizes, so that when the SOA end-face is spaced from the end-face of the silicon waveguide chip by 7 micrometers, 1dB alignment tolerances of ± 1.3 micrometers and ± 0.9 micrometers in the transverse direction and the longitudinal direction are realized, respectively, which are still too small, require very high-precision expensive alignment equipment, and take a long time for alignment; meanwhile, the position alignment in the longitudinal direction is easily influenced by the thickness of the soldering tin, and the optical coupling loss is greatly increased when the thickness of the soldering tin changes by 1 micron.

The optical assembly provided by the application can effectively solve the problems so as to realize low-loss and high-yield integration of the first optical unit and the second optical unit (such as a high-power mature laser and a passive waveguide chip, and an SOA and a silicon waveguide chip). The following coupling mode of the laser and the passive optical chip can be particularly replaced: vertical grating coupler, end coupling, laser prepared by direct growth on heterogeneous material substrate, and evanescent coupling scheme for preparing optical coupling structure on laser or passive chip.

Fig. 5 and 6 are side views of an optical assembly 100 according to still other embodiments of the present application.

As shown in fig. 5, the optical assembly 100 may further include a plurality of first optical units, a plurality of second optical units, a plurality of optical interconnection units, and a substrate 150, and the

optical interconnection units

103, 106, 107 may be located on the substrate 150 to couple the adjacent first optical units and second optical units, thereby achieving optical transmission between the respective optical units. The same Nanoteeth (or vertical taper) optical interconnection unit is used for splicing small optical units to form an optical unit network (optical die), for example, a structure for integrating a plurality of passive optical chips and lasers is realized. The individual optical interconnect elements may be fabricated on the same wafer and then cut so that they are of the same thickness to achieve a complete bond with the individual optical elements.

As shown in fig. 6, at least one of the first light unit 101 and the second light unit 102 further includes a height adjusting stage 160 to adjust a height difference between the first light unit 101 and the second light unit 102. Because different optical units may come from different batches of DUV photoetching, the thicknesses of silicon wafers used may be slightly different, and the tops of the optical units are not equal in height when the optical units are placed on the same substrate, which is not beneficial to the bonding of optical interconnection units, a piezoelectric ceramic (PZT) device with adjustable height is used at the bottom of each optical unit to adjust the tops of the optical units to be flush.

The operation method of splicing each optical unit (e.g., integrated III-V laser) using the optical interconnection unit may include moving monitoring of different parts, and through the above structural design of each optical unit provided by the present application, alignment tolerance of splicing may be improved, optical loss may be reduced, and product yield may be further improved.

Still another embodiment of the present application provides an optical chip, which includes a plurality of the optical assemblies described above.

The optical interconnection unit which is separately prepared is used for bonding and integrating the optical units which are separately prepared, such as the laser and the passive waveguide chip (lithium niobate, silicon nitride and other chips), so that the optical units can realize smaller coupling loss and larger alignment tolerance while ensuring higher yield due to the fact that the optical units respectively use respective mature processes, the overall performance and the yield of final products can be obviously improved, and the product cost is reduced.

While the above specification concludes with claims defining the preferred embodiments of the invention that are presented in connection with the above description and the appended drawings, it is not intended to be limiting of the invention. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. Therefore, the appended claims should be construed to cover all such changes and modifications as fall within the true spirit and scope of the application. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of this application.

Claims

1. An optical assembly, comprising:

a first light unit including a first waveguide;

a second light unit comprising a second waveguide, the second light unit disposed adjacent to the first light unit; and

an optical interconnect unit including a third waveguide,

wherein the same surface of the third waveguide couples the first waveguide and the second waveguide such that light enters the third waveguide from the first waveguide by evanescent coupling and then enters the second waveguide by evanescent coupling; and

the surface width of the tail end of the first waveguide is gradually increased from a first width to a second width along the propagation direction of the light in the first waveguide, and the surface width of the head end of the second waveguide is gradually decreased from a third width to a fourth width along the propagation direction of the light in the second waveguide.

2. The optical assembly of claim 1, wherein the first optical unit is a laser and the second optical unit is a passive optical device.

3. The optical assembly of claim 1, wherein the first waveguide is an indium gallium arsenic phosphide waveguide, the second waveguide is a lithium niobate waveguide, and the third waveguide is a silicon waveguide.

4. The optical assembly of claim 1, wherein the optical assembly further comprises a dielectric layer between the third waveguide and at least one of the first waveguide and the second waveguide.

5. The optical assembly of claim 1, wherein at least one of the first, second, and third waveguides includes a waveguide core layer and/or a cladding layer external to the waveguide core layer.

6. The optical assembly of claim 1, wherein the optical assembly further comprises a substrate, the optical interconnect unit being located over the substrate.

7. The optical assembly of claim 1, wherein the optical interconnect unit comprises a third waveguide array comprised of a plurality of the third waveguides.

8. The optical assembly of claim 1, wherein at least one of the first and second light units further comprises a height adjustment stage to adjust a height difference between the first and second light units.

9. A photonic chip comprising a plurality of optical components according to any of the preceding claims 1-8.

10. An optical assembly, comprising:

a plurality of first light units comprising a first waveguide;

a plurality of second light units comprising second waveguides and disposed adjacent to the first light units; and

a plurality of optical interconnect units including a third waveguide array,

the same surface of the third waveguide is coupled with the first waveguide and the second waveguide, so that light enters the third waveguide from the first waveguide by means of evanescent coupling and then enters the second waveguide by means of evanescent coupling;

the surface width of the tail end of the first waveguide is gradually increased from a first width to a second width along the propagation direction of the light in the first waveguide, and the surface width of the head end of the second waveguide is gradually decreased from a third width to a fourth width along the propagation direction of the light in the second waveguide; and

the adjacent first light unit and the second light unit are coupled by the optical interconnection unit.