Alignment of a laser chip and another chip using a selective coupler

Abstract

This invention discloses a method for aligning a laser chip and an electro-optic chip. The method may include: guiding a detection signal through the electro-optic chip and toward the laser chip; detecting a reflected detection signal by a first detector of the electro-optic chip, the reflected detection signal being reflected from the laser chip; determining whether the laser chip is aligned with the electro-optic chip based on the reflected detection signal; wherein the detection signal and the reflected detection signal are within a first wavelength range.

Description

Background Technology

[0001] Precise alignment of the laser chip and silicon chip is necessary as building blocks used in the design and fabrication of photonic integrated circuits (PICs) in SiP technology. In relevant designs, the laser chip includes a laser waveguide capable of outputting laser radiation to a waveguide on the silicon chip. For effective coupling of the laser radiation, the laser and the corresponding waveguide on the silicon chip must be correctly aligned. Typically, the silicon chip contains other photonic integrated circuits (PICs) driven by the optical signals from the laser to achieve specific functions for a particular application.

[0002] Activating the laser chip during alignment with silicon chips is expensive, complex, and presents challenging problems, especially for equipment manufactured in large-scale production. Therefore, there is a growing demand for alignment methods that do not require laser activation; these methods are defined as passive alignment methods.

[0003] Typically, these alignment methods require the fabrication of additional components, such as waveguides, markers, and other elements, on both the laser and the silicon die component. The manufacturing cost of these additional components on the laser die is significantly higher than that on the silicon die component. Therefore, simplifying fabrication and / or die size can have a greater impact on the manufacturing cost of a PIC circuit assembly consisting of a laser chip and a silicon chip.

[0004] Therefore, there is a strong incentive to develop alignment methods that can simplify the alignment process and reduce the manufacturing cost of laser dies / chips. Furthermore, there is a strong incentive to develop alignment methods that have virtually no impact on the performance of associated PIC circuits composed of assembled lasers and silicon chips. Attached Figure Description

[0005] Figure 1 It is an example of a system;

[0006] Figure 2 It is an example of a system;

[0007] Figure 3 An example of a part of the electro-optical chip of the system;

[0008] Figure 4 An example of a part of the electro-optical chip of the system;

[0009] Figure 5 An example of a part of the electro-optical chip of the system;

[0010] Figure 6 An example of a method; and

[0011] Figure 7 This is an example of a method. Detailed Implementation

[0012] In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the invention. However, those skilled in the art will understand that the invention can be practiced without these specific details. In other instances, well-known methods, steps, and components have not been described in detail so as not to obscure the invention.

[0013] The subject matter considered to be the present invention is specifically pointed out and explicitly claimed in the concluding section of the specification. However, the present invention, with respect to configuration and operation methods, together with its objects, features and advantages, can be best understood by referring to the following detailed description in conjunction with the accompanying drawings.

[0014] It should be understood that, for the sake of brevity and clarity, the elements shown in the accompanying drawings are not necessarily drawn to scale. For example, for clarity, the dimensions of some elements may be enlarged relative to others. Furthermore, where deemed appropriate, reference numerals may be repeated in the drawings to indicate corresponding or similar elements.

[0015] Since most of the illustrated embodiments of the present invention can be implemented using electronic components and circuits known to those skilled in the art, details will not be explained in any way that is considered necessary beyond the scope shown in the illustrations above, in order to understand and comprehend the basic concepts of the present invention and to avoid confusion or deviation from the intent of the present invention.

[0016] Any references to the method in the specification should be adapted to the device or system capable of performing the method, with the necessary modifications.

[0017] Any references to the system or device in the specification should be adapted to the methods that can be performed by said system, with the necessary modifications.

[0018] Any combination of any drawings, any part of the specification, and / or any module or unit listed in any claim may be provided.

[0019] Any combination of any steps of any method shown in the instruction manual and / or accompanying drawings may be provided.

[0020] Any combination of any subject matter that can be claimed.

[0021] Any combination of systems, units, components, processors, and sensors shown in the specification and / or drawings may be provided.

[0022] A method and system are provided for passive alignment between a laser chip and an electro-optic chip, the electro-optic chip including one or more optical elements configured to receive radiation from the laser chip without laser activation and without the use of expensive alignment equipment, such as very expensive and very slow-operating optical backscatter reflectors.

[0023] The alignment electro-optic chip may include a wavelength selective coupler (WSC) configured to define a first WSC optical path between the laser chip and a first portion of the electro-optic chip, and a second WSC optical path between the laser chip and a second portion of the electro-optic chip.

[0024] The first part of the electro-optic chip may be or may include an alignment circuit.

[0025] The second part of the electro-optic chip may be or may include an electro-optic unit such as a photonic integrated circuit (PIC).

[0026] The second part may also be referred to as the operation part, main part, functional part, or post-alignment part of the electro-optic chip.

[0027] The first WSC path and at least some components of the first part of the electro-optic chip form a first optical path used in the alignment process.

[0028] The first optical path can be configured to transmit radiation (also known as probe radiation) within a first wavelength range – and the first wavelength can be the center wavelength of that range.

[0029] The first optical path can be used to transmit radiation from a radiation source (also called an alignment radiation source) located within the electro-optic chip. The alignment radiation source can be external to the electro-optic chip—and the electro-optic chip can be optically coupled to the alignment radiation source and configured to transmit radiation from the alignment radiation source to the laser chip via the first optical path.

[0030] The first optical path may include a laser waveguide or may use different waveguides (e.g., auxiliary waveguides) of the laser chip.

[0031] The second WSC path and at least some components of the second part of the electro-optic chip form a second optical path, which can be used after the alignment process is completed.

[0032] The second optical path can be configured to transmit radiation within a second wavelength range—and the second wavelength can be the center wavelength of that range.

[0033] The first wavelength may be different from the second wavelength.

[0034] The first wavelength range may be different from the second wavelength range. The first and second wavelength ranges may not overlap.

[0035] The first and second wavelength ranges can be separated by a certain distance from each other so that the WSC can easily distinguish them.

[0036] Due to the wavelength selection behavior of the WSC (distinguishing between the first and second wavelength ranges), once alignment is achieved, it is not necessary to move the electro-optic chip relative to the laser chip.

[0037] The second optical path can be used to transmit radiation from the laser chip to the electro-optic chip.

[0038] Using WSC during alignment allows for wafer-level pick-and-place processes coupled to the grating coupler to occur. This enables alignment methods that are independent of the electro-optic unit design and application (as in methods based on optical backscattering reflectometers (OBR)). This method can also be used for high-loss electro-optic units—where applying OBR-based methods can be problematic. OBR-based methods require very expensive OBR measurement equipment and complex, slow scan patterns. See, for example, Flip-chip Integration of InP to SiN Photonic Integrated Circuits, M. Therurer et al., Journal of Lightwave Technology, Vol. 38, No. 9, May 2020.

[0039] The first path may include a coupler such as a grating coupler. Such a coupler may or may not be provided in the second path.

[0040] The second path can be considered as the system's operational path, main path, functional path, or post-alignment path—and it can exhibit lower losses than the first path.

[0041] The second path can be independent of the first path—so that any energy loss that occurs during alignment will not affect radiation passing through the second path.

[0042] The method may include performing back-reflection setup measurements, for example, using a special PIC design with an external source and power meter to obtain a single reading (or several readings). This allows for very rapid scanning placement and alignment. This contrasts with OBR-based methods—which require scanning wavelengths at each location—a very time-consuming process at each location and necessitates analysis of the OBR data.

[0043] During alignment, the laser chip is irradiated along the first path—and the reflected radiation is reflected back along the first path. The reflection can originate primarily (almost solely) from the laser waveguide of the laser chip (a small amount of reflection can originate from the WSC). A readout method is possible. This contrasts with OBR-based methods. This method can be applied to any electro-optic chip with any electro-optic unit, even with high losses. This contrasts with OBR-based methods, which are susceptible to reflections from various components requiring OBR (e.g., free space, electro-optic components, lasers).

[0044] The method avoids laser activation, which is expensive and complex for mass production of these devices. Furthermore, in the disclosed method, the first waveguide is directly aligned with the laser waveguide, requiring virtually no passive alignment elements attached to the laser die components. This results in a high-precision passive method with accuracy similar to active alignment methods.

[0045] Figure 1 A system 100 is shown, comprising a laser chip 40, an electro-optic chip 10, and a refractive index matching layer (IML) 30.

[0046] The first detector 12 and the first radiation source 13 may also be included in the system 100. The first detector 12 and the first radiation source 13 may be located outside the electro-optic chip 10 (e.g., Figure 1 (as shown), but at least one of them may belong to the electro-optic chip 10.

[0047] The first detector 12 and the first radiation source 13 can be optically coupled to the electro-optic chip in various ways—for example, through an optical fiber array 29 comprising spaced-apart optical fibers (illustrated as lines passing through a rectangle denoted as 29).

[0048] It should be noted that the system 100 may not include IML30.

[0049] The laser chip 40 includes a laser waveguide 44 located on top of the laser diode body / chip 43 and is illustrated as having a far-end reflective element such as a high-reflectivity coating 42 and a near-end reflective element such as a low-reflectivity coating 41.

[0050] The low-reflection coating 41 may be an anti-reflection coating (ARC), which is designed to reduce internal reflections from the laser chip output surface back to the laser chip.

[0051] The distal reflective element may be a wavelength selective element (e.g., a low-bandwidth reflective layer) configured to have high reflectivity in a first wavelength range and low reflectivity in a second wavelength range.

[0052] The electro-optic chip 10 may include WSC20, a first part 31, and a second part 32.

[0053] The first part 31 may include a first coupling unit 18.

[0054] The first radiation source 13 is optically coupled to the first port 18a of the first coupling unit 18 via an optical fiber and through the port of the electro-optic chip 10.

[0055] The first detector 12 is optically coupled to the second port 18b of the first coupling unit 18 via another optical fiber and through another port of the electro-optic chip 10.

[0056] The third port 18c of the first coupling unit 18 is optically coupled to the first WSC port 20a of the WSC20.

[0057] The fourth port 18d of the first coupling unit is grounded or ignored.

[0058] Part 32 includes an electro-optical unit, such as a photonic integrated circuit (PIC) 22. PIC 22 may include a receiver, may include transmission path optics, and may be a sensor, modulator, biosensor, or any other PIC.

[0059] The first port 22a of PIC22 is optically coupled to the second WSC port 20b of WSC20 via PIC waveguide 14.

[0060] The second port 22b of PIC22 can be optically coupled to any other unit—such as the rear PIC unit 15.

[0061] The third port 20c of WSC22 is optically coupled to the first waveguide 11.

[0062] The fourth port 20d of WSC22 is grounded or ignored.

[0063] The following example illustrates the process of a signal passing through the system. A channel can modify any signal—for example, reduce signal strength, add noise, or perform any other operation. For the sake of brevity, the same terminology is used to describe the signal throughout the process.

[0064] During the alignment process, the detection signal 61 is

[0065] a. Produced by the first radiation source 13.

[0066] b. Received by the first port 18a of the first coupling unit 18.

[0067] c. Passing through the first coupling unit 18 and outputting from the third port 18c of the first coupling unit 18.

[0068] d. Received from the first port 20a of WSC20.

[0069] e. Provided by the first WSC optical path to the third port 20c of the WSC.

[0070] f. Output from the third port 20c to the first waveguide 11.

[0071] g. Transmitted to the laser chip 40 – through IML30.

[0072] When the first waveguide 11 is aligned with the laser waveguide 44, the detection signal 61 also passes through the laser waveguide and is reflected from the far-end reflective element to provide a reflected detection signal 62.

[0073] The reflected detection signal 62:

[0074] a. Propagate through the laser waveguide 44 to the first waveguide 11.

[0075] b. Propagate along the first waveguide 11.

[0076] c. Enter the third port 20c of WSC.

[0077] d. Provided to the first port 20a of the WSC by the first WSC optical path.

[0078] e. Received by the third port 18c of the first coupling unit 18.

[0079] f. Passing through the first coupling unit 18 and outputting from the second port 18b of the first coupling unit 18.

[0080] g. Detected by the first detector 12.

[0081] When the first waveguide 11 is not aligned with the laser waveguide 44, the detection signal 61 may be almost (or even negligibly) not reflected from the near-end reflective element to provide the reflected detection signal.

[0082] In any case—it is desirable that the reflection detection signal 62 from the aligned laser chip is clearly different from the reflection detection signal 62 from the misaligned laser chip—it is possible to determine whether the laser chip is aligned (with the electro-optic chip).

[0083] The detection signal from the first detector 12 can be processed by the controller 70 to assist the alignment process.

[0084] The controller 70 can control the spatial relationship between the laser chip 40 and the electro-optic chip 100—for example, by controlling or requesting one (or both) of the chips to move until an alignment stop condition is met—for example, achieving alignment, alignment failure, performing a predefined number of alignment iterations, etc.

[0085] For example, one or more of the electro-optic chip and the laser chip can be mechanically manipulated with a sufficiently large spatial resolution—for example, along the x and y directions. This mechanical operation can be performed along a plane perpendicular to the optical axis of the laser waveguide. It should be noted that at the start of the alignment process, the electro-optic chip and the laser chip can be coarsely aligned.

[0086] During the alignment process, the intensity of the reflected detection signal can provide an indication of the degree of alignment—for example, a stronger reflected detection signal may indicate better alignment.

[0087] The detection signal 61 and the reflected detection signal 62 pass through the first optical path.

[0088] In operation mode, the laser chip 40 outputs a laser signal 63, which is:

[0089] a. Received by the first waveguide 11.

[0090] b. Enter the third port 20c of WSC.

[0091] c. The second WSC optical path provides access to the second port 20b of the WSC.

[0092] d. Propagation on PIC waveguide 14.

[0093] e. Received via the first port 22a of the PIC22.

[0094] f. Optical processing by PIC22.

[0095] It is optically coupled to the second port 20b of WSC20 via PIC waveguide 14.

[0096] The optically processed laser signal can be output from the second port 22b of PIC22 to the rear PIC unit 15.

[0097] Once aligned, the positions of the laser chip and the electro-optic chip can be fixed. For example, the laser chip can be attached to the electro-optic chip, the electro-optic chip can be attached to the laser chip, or one or both chips can be attached to a third component.

[0098] The IML30 is configured to fill the air gap between the laser chip and the electro-optic chip. The IML30 can also be configured to mechanically bond the laser chip to the electro-optic chip.

[0099] The IML30 can be configured to reduce reflections (related to radiation in a first wavelength range and a second wavelength range) that can be caused by refractive index mismatch due to the air gap between the laser chip and the electro-optic chip.

[0100] IML30 can be a UV adhesive manufactured in a gel phase. In this case, the refractive index of the first waveguide can be determined by the core and cladding, which can be made of oxide, nitride, silicon, or any other dielectric material.

[0101] The low-reflection coating can be designed to have a refractive index that matches the refractive index of the first waveguide 11, thereby reducing the internal reflection amplitude between the laser chip 40 and the electro-optic chip 10.

[0102] The first waveguide 11 may include multiple waveguide segments of Nit and Ox, and oxynitride layers.

[0103] The first waveguide 11 may include a tapered portion aligned with the edge of the silicon layer.

[0104] The first waveguide 11 may include a combination of Nit and Ox, and oxynitride layers.

[0105] Figure 2 It is system 101, which includes laser chip 40, electro-optic chip 10 and refractive index matching layer (IML) 30.

[0106] The first detector 12, the second detector 12', and the first radiation source 13 may also be included in the system 101. The first detector 12, the first radiation source 13, and the second detector 12' may be located outside the electro-optic chip 10 (e.g., Figure 1 (as shown), but at least one of them may belong to the electro-optical chip 10.

[0107] The first detector 12, the second detector 12', and the first radiation source 13 can be optically coupled to the electro-optic chip in various ways—for example, through an optical fiber array 29 comprising spaced-apart optical fibers (illustrated as lines passing through a rectangle denoted as 29).

[0108] The difference between system 101 and system 100 is that system 101 has a probe signal measurement circuit that includes a fifth port 18e of the first coupling unit and a second detector 12'. An additional port 16e provides a sample of the probe signal, and the second detector 12' measures this sample.

[0109] The detection signal from the second detector can be sent to the controller 70. The controller 70 can determine the difference between the detection signal and the reflected detection signal.

[0110] Figure 3 An example of a portion of the electro-optic chip 10 is shown, particularly an example of the first coupling unit 18 and WSC20.

[0111] The first coupling unit 18 includes a first coupler 12a for providing reflected detection radiation to the first detector 12 (via the second port 18b), a second coupler 13a for receiving the detection radiation from the first radiation source 13 (via the port 18a), a third coupler 14a for providing a sample of the detection radiation to the second detector 12' (via the port 18e), and a fourth coupler 17.

[0112] Any type of coupler is possible.

[0113] The first and second couplers can be grating couplers.

[0114] The fourth coupler 17 can be a 2x1 directional coupler, which can be implemented by a 2x2 directional coupler having a terminal connected to the fourth port 17d. The terminal almost completely eliminates the back reflection of the probe signal and the reflected probe signal.

[0115] The first port 17a of the fourth coupler 17 is optically coupled to the output of the second coupler 12a.

[0116] The second port 17b of the fourth coupler 17 is optically coupled to the output of the first coupler 13a.

[0117] The third port 17c of the fourth coupler 17 is optically coupled to the first port 20a of the WSC20.

[0118] The WSC20 can be implemented in various ways—for example... Figure 3 The WSC is shown as a 2x2 directional coupler with a terminal connected to the fourth port 20d. The terminal almost completely eliminates the back reflection of both the probe signal and the reflected probe signal.

[0119] The WSC can be replaced by an SM optical 2x1 multiplexer or interpolation filter, configured to support a first internal optical path for radiation in a first wavelength range and a second internal optical path for radiation in a second wavelength range.

[0120] The WSC may include two parallel waveguides coupled by a ring resonator device, such that these waveguides are selectively coupled in a first wavelength range to route the signal in the first wavelength range to the coupler unit, and the signal is guided to the PIC in a second wavelength range.

[0121] The WSC device may include a ring resonator coupler that couples incident light from the coupler unit with a resonant wavelength centered at a first wavelength, aligned with the waveguide at the silicon component.

[0122] The WSC may include a ring resonator coupler consisting of two injected n-type and p-type segments and an intrinsic segment, wherein the n-type and p-type segments are externally contacted with a voltage source for applying a voltage to the injected n-type and p-type sides, thereby modifying the refractive index of the ring resonator so that its resonant coupling wavelength can be adjusted.

[0123] The WSC may include an open-loop resonator made of dielectric maleic acid or a dielectric material, which can be fabricated on the silicon chip side and can couple incident light from the coupler unit with a resonant wavelength centered at the first wavelength, aligned with the waveguide at the silicon component.

[0124] The WSC may include a WSC made of a metal open-ring resonator.

[0125] The WSC may include a 1D, 2D, or 3D photonic crystal structure consisting of cylindrical rod-shaped holes, or any shape made of dielectric or metallic materials, which can be fabricated on a silicon chip and can couple incident light from the coupler unit with a resonant wavelength centered at the first wavelength (XI) to the waveguide at the silicon component.

[0126] It should be noted that the WSC can provide selective routing of signals across more than two different wavelength ranges—and it has more than two WSC optical paths. This can be achieved by cascading WSC devices and / or using multiple directional couplers.

[0127] Figure 4 An example of a portion of the electro-optic chip 10 is shown—in particular, an example of the first coupling unit 18 and WSC20'.

[0128] Figure 4 The WSC' is illustrated as including a multimode jamming device (MMI) 21 instead of... Figure 3 The diagram shows a directional coupler (DC).

[0129] Figure 5An example of a portion of the electro-optic chip 10 is shown—in particular, an example of the first coupling unit 18 and WSC20'.

[0130] Alternatively utilize radiation from the first radiation source (e.g.) Figure 4 As shown—a dedicated radiation source (e.g., different from the first radiation source 13) is optically coupled (via loop 19) to the second detector 12'—thereby checking whether the electro-optic chip 10 is aligned with the second detector 12'. This provides a feedback branch that does not use the radiation sent to the laser chip.

[0131] Figure 6 This is an example of method 400.

[0132] Method 400 can be used to align laser chips with electro-optic chips.

[0133] Method 400 may include one or more alignment iterations.

[0134] Each alignment iteration can begin at step 410, which involves directing the probe signal from the electro-optic chip to the laser chip.

[0135] Step 410 can be followed by step 420, which involves detecting a reflection detection signal by the first detector of the electro-optic chip, the reflection detection signal being reflected from the laser chip.

[0136] The detection signal and the reflected detection signal are within the first wavelength range.

[0137] The reflected detection signal passes through the first optical path of the electro-optic chip, and the first optical path is configured to transmit signals within a first wavelength range.

[0138] The first optical path is different from the second optical path of the electro-optic chip, which is configured to transmit signals in a second wavelength range different from the first wavelength range.

[0139] The laser chip is configured to output a laser signal in a second wavelength range.

[0140] Steps 410 and 420 are performed while maintaining the current spatial relationship between the laser chip and the electro-optic chip. This is illustrated as step 440, which maintains the current spatial relationship between the laser chip and the electro-optic chip.

[0141] Step 420 can be followed by step 430, which is to determine whether the laser chip is aligned with the electro-optic chip based on the reflection detection signal.

[0142] If alignment is required—step 430 can be followed by a post-alignment step 450.

[0143] The post-alignment step 450 may include, for example, fixing the spatial relationship between the laser chip and the electro-optic chip.

[0144] If misalignment occurs, step 430 may include changing (step 460) the current spatial relationship and jumping to step 410.

[0145] Step 460 can be performed in any way—for example, following a set of predetermined spatial relationships, searching for local or global alignment extrema, etc.

[0146] It should be noted that if a stopping condition is met—for example, if alignment is not achieved in at least the first few alignment iterations—the alignment can be declared a failure.

[0147] Another stopping condition is that a certain degree of alignment (though not perfect) is achieved—after a second series of alignment iterations—which can then declare alignment successful.

[0148] Step 410 may include receiving a probe signal through a first wavelength selective coupler (WSC) port of the WSC of the electro-optic chip, guiding the probe signal from the first WSC port to a second WSC port through a first WSC optical path, the first WSC optical path being configured to transmit a signal within a first wavelength range, and outputting the probe signal from the second WSC port to a first waveguide.

[0149] Step 420 may include receiving a reflected detection signal from the first waveguide through the second WSC port; and guiding the reflected detection signal from the second WSC port to the first WSC port through the first WSC optical path.

[0150] The third WSC port of the WSC is optically coupled to the second WSC port via the second WSC optical path, which is configured to transmit signals in the second wavelength range.

[0151] Method 400 may include step 460, which involves measuring a sample of the probe signal to provide a probe signal measurement. Step 430 may respond to the measurement result—specifically, to the difference between the probe signal (as represented by the sample) and the reflected probe signal.

[0152] Method 400 can be performed when the laser of the laser chip is deactivated.

[0153] Steps 410 and 420 can be performed by the alignment unit of the electro-optic chip.

[0154] Figure 7 This is an example of method 500.

[0155] Method 500 can be used to operate laser chips.

[0156] Method 500 may include step 510, which is to output a laser signal from the laser chip to an electro-optic chip aligned with the laser chip.

[0157] Step 510 can be followed by step 520, which involves passing the laser signal through the second optical path of the electro-optic chip, the second optical path being configured to transmit a signal in a second wavelength range, wherein the laser signal is in the second wavelength range.

[0158] Alignment between the electro-optic chip and the laser chip can be achieved by performing any step of method 400.

[0159] Successful completion of method 400 can be a prerequisite for executing steps 510 and 520.

[0160] The silicon chip / electro-optic chip can be fabricated from a silicon-on-insulator (SOI) wafer. The SOI wafer may include the following adhesion layers:

[0161] a. Top silicon layer

[0162] b. An insulating layer made of OX (labeled as BOX layer)

[0163] c. Bottom silicon substrate.

[0164] The PIC elements of the electro-optic chip / silicon chip, such as all waveguide structures, couplers, grating couplers, WSC devices, other couplers and all other devices, can be fabricated on the top layer of the SOI wafer silicon.

[0165] While the foregoing written description of the invention enables those skilled in the art to make and use what is currently considered the best mode, those skilled in the art will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiments, methods, and examples described herein. Therefore, the invention should not be limited to the embodiments, methods, and examples described above, but should be limited to all embodiments and methods within the scope and spirit of the invention as claimed.

[0166] Any references included or contained herein shall be modified as necessary to apply to the composition and / or "consistently of...".

[0167] The invention has been described in the foregoing specification with reference to specific examples of embodiments thereof. However, it will be apparent that various modifications and changes can be made without departing from the broader spirit and scope of the invention as set forth in the appended claims.

[0168] Those skilled in the art will recognize that the boundaries between logic blocks are merely illustrative, and alternative implementations may combine logic blocks or circuit elements, or alternatively decompose the various logic blocks or circuit elements functionally. Therefore, it should be understood that the architecture described herein is merely exemplary, and many other architectures can actually achieve the same functionality.

[0169] Any arrangement of components used to achieve the same function is a valid "association," thus achieving the desired functionality. Therefore, any two components combined to achieve a specific function can be considered as mutually "associated," thus achieving the desired functionality, regardless of structure or intermediate components. Similarly, any two such correlated components can also be considered as "operably connected" or "operably coupled" to each other to achieve the desired functionality.

[0170] Furthermore, those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations can be combined into a single operation, a single operation can be distributed among additional operations, and operations can be performed with at least partial overlap in time. Additionally, alternative embodiments may include multiple instances of a particular operation, and the order of operations may be varied in various other embodiments.

[0171] For example, in one embodiment, the illustrated examples can be implemented as circuitry located on a single integrated circuit or within the same device. Alternatively, these examples can be implemented as any number of separate integrated circuits or separate devices interconnected with each other in a suitable manner.

[0172] However, other modifications, variations, and alternatives are also possible. Therefore, the specification and drawings are considered illustrative rather than restrictive.

[0173] In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word “comprising” does not exclude the presence of other elements or steps besides those listed in the claims. Furthermore, the term “a” (“a” or “an”) as used herein is defined as one or more. Moreover, the use of introductory phrases such as “at least one” and “one or more” in the claims should not be construed as limiting any particular claim containing such an introduced element to an invention containing only one such element, even if the same claim includes the introductory phrase “one or more” or “at least one” and the indefinite article, such as “a” (“a” or “an”). The same applies to the use of definite articles. Unless otherwise stated, terms such as “first” and “second” are used to arbitrarily distinguish the elements described by these terms. Therefore, these terms are not necessarily intended to indicate the time or other priority of these elements, and the fact that certain measures are listed only in mutually different claims does not mean that combinations of these measures cannot be used advantageously.

[0174] While certain features of the invention have been described and recorded herein, many modifications, substitutions, alterations, and equivalents will now occur to those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all such modifications and variations that fall within the true spirit of the invention.

[0175] It should be understood that, for clarity, various features of embodiments of the present disclosure described in the context of individual embodiments may also be provided in combination in a single embodiment. Conversely, for brevity, various features of embodiments of the present disclosure described in the context of individual embodiments may also be provided individually or in any suitable sub-combination.

[0176] Those skilled in the art will understand that the embodiments of this disclosure are not limited to the specific explanations and descriptions above. Rather, the scope of the embodiments of this disclosure is defined by the appended claims and their equivalents.

Claims

1. A method for aligning a laser chip and an electro-optic chip, the method comprising: The probe signal is guided through the electro-optic chip and directed toward the laser chip; The reflection detection signal is detected by the first detector of the electro-optic chip, and the reflection detection signal is reflected from the laser chip; The alignment of the laser chip with the electro-optic chip is determined based on the reflected detection signal. Wherein, the detection signal and the reflected detection signal are within the first wavelength range; The guidance and detection are performed while maintaining the current spatial relationship between the laser chip and the electro-optic chip; The reflected detection signal passes through the first optical path of the electro-optic chip, and the first optical path is configured to transmit a signal within a first wavelength range; Wherein, the first optical path is different from the second optical path of the electro-optic chip, and the second optical path is configured to transmit signals in a second wavelength range different from the first wavelength range; and The laser chip is configured to output a laser signal in a second wavelength range; The method is characterized by further comprising: The detection signal is received through the first wavelength selective coupler port of the wavelength selective coupler of the electro-optic chip; The probe signal is directed from the first wavelength selective coupler port to the second wavelength selective coupler port via a first wavelength selective coupler optical path configured to transmit the signal in the first wavelength range; The probe signal is output from the port of the second wavelength selective coupler to the first waveguide; The reflected detection signal from the first waveguide is received through the second wavelength selective coupler port; and The reflected detection signal from the port of the second wavelength selective coupler is directed to the port of the first wavelength selective coupler through the optical path of the first wavelength selective coupler; and The third wavelength selective coupler port of the wavelength selective coupler is optically coupled to the second wavelength selective coupler port via the second wavelength selective coupler optical path, which is configured to transmit signals within the second wavelength range.

2. The method according to claim 1, further comprising changing the current spatial relationship between the laser chip and the electro-optic chip when it is determined that the laser chip is not aligned with the electro-optic chip.

3. The method of claim 1, further comprising measuring a sample of the probe signal to provide a probe signal measurement.

4. The method of claim 1, further comprising performing the guidance and the detection when the laser of the laser chip is deactivated.

5. The method of claim 1, wherein, The guidance and detection are performed by the alignment unit of the electro-optic chip.

6. A system comprising a laser chip and an electro-optic chip; wherein, The laser chip is configured to output a laser signal in a second wavelength range; The electro-optic chip includes a first optical path, a second optical path different from the first optical path, and a first detector; The first optical path is configured to guide the detection signal from the electro-optic chip toward the laser chip and to guide the reflected detection signal toward the first detector. Wherein, the detection signal and the reflected detection signal are within a first wavelength range different from the second wavelength range; and The second optical path is configured to transmit signals within a second wavelength range; The system is characterized by further comprising: A wavelength selective coupler is configured to receive a reflection detection signal from the laser chip and output a signal to a portion of the first optical path to receive a laser signal from the laser chip and output a laser signal to a portion of the second optical path; The wavelength selective coupler includes a first wavelength selective coupler port, a second wavelength selective coupler port, and a third wavelength selective coupler port. The first wavelength selective coupler port is coupled to the second wavelength selective coupler port via a first wavelength selective coupler optical path, which is configured to transmit signals within a first wavelength range. The second wavelength selective coupler port is coupled to the third wavelength selective coupler port via a second wavelength selective coupler optical path, which is configured to transmit signals within a second wavelength range.

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