Integrated dense wavelength division multiplexing laser array

Abstract

Integrated laser arrays, photonic devices, packages, and systems are disclosed. An example integrated laser array includes a first laser and a second laser, each laser including a light emitter structure and a waveguide having a grating. In one aspect, the effective pitch of the gratings of the first and second lasers differs by less than about 5 angstroms, while the gratings of the first and second lasers are fabricated at a resolution of at least 1 nm. In another aspect, each laser includes a waveguide having a left sidewall grating and a right sidewall grating, the effective widths of the waveguides of the first and second lasers are different, and an offset between the left sidewall grating and the right sidewall grating of the second laser is different than an offset between the left sidewall grating and the right sidewall grating of the first laser. The integrated laser arrays described herein may be particularly suited for implementation in dense wavelength division multiplexing systems.

Description

BACKGROUND OF THE INVENTION

[0001] Many emerging applications such as optical interconnections (e.g., fiber optic communications), optical computing, or light detection and ranging (LIDAR) use lasers to generate electromagnetic signals (such signals are hereinafter simply referred to as "light" or "optical signals") having wavelengths in the optical and microwave portions of the electromagnetic spectrum. A variety of factors can affect the cost, quality, and robustness of photonic devices that integrate light-emitting components and components for guiding and / or manipulating light. Such photonic devices may be referred to as "integrated photonic devices". Physical constraints such as space / surface area, as well as power consumption, can impose further constraints on integrated photonic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings.

[0003] Figure 1 is a schematic diagram of an example photonic device having an integrated laser array according to an embodiment.

[0004] Figures 2A - 2B is a top view of two example lasers having surface gratings according to various embodiments.

[0005] Figures 3A - 3B is a top view of two example lasers having sidewall gratings according to various embodiments.

[0006] Figures 4A - 4B is a top view of two example lasers having surface gratings and sidewall gratings according to various embodiments.

[0007] Figure 5 illustrates a top view of a waveguide having surface gratings with different effective pitches that can be used in different lasers of an integrated laser array according to an embodiment.

[0008] Figure 6 illustrates according to an embodiment Figure 5 a cross-sectional side view of a waveguide, where perturbations of the grating are implemented as trenches.

[0009] Figure 7 illustrates according to an embodiment Figure 5 a cross-sectional side view of a waveguide, where perturbations of the grating are implemented as ridges.

[0010] Figure 8 illustrates a top view of a waveguide having sidewall gratings and different effective widths that can be used in different lasers of an integrated laser array according to an embodiment, and where perturbations of the grating are implemented as trenches.

[0011] Figure 9The figure shows a top view of a waveguide with sidewall gratings and different effective widths that can be used in different lasers of an integrated laser array, where the perturbation of the grating is implemented as a ridge.

[0012] Figure 10A and Figure 10B A cross-sectional view of a waveguide of an embodiment is shown with sidewall gratings on two different sidewalls. Figure 8 and Figure 9 A cross-sectional side view of one of the waveguides.

[0013] Figure 11 Is a top view of a wafer and die that can be included in a photonic device having an integrated laser array according to an embodiment.

[0014] Figure 12 Is a side cross-sectional view of an example microelectronic package that can include a photonic device having an integrated laser array according to an embodiment.

[0015] Figure 13 Is a block diagram of an example photonic device that can include an integrated laser array according to an embodiment. Detailed Description

[0016] Integrated laser arrays, photonic devices, packages, and systems are disclosed. Example integrated laser arrays include a first laser and a second laser, each laser including a light emitter structure and a waveguide having a grating. In one aspect, the effective pitch of the gratings of the first laser and the second laser differs by less than about 5 angstroms, and the gratings of the first laser and the second laser are fabricated with a resolution of at least 1 nanometer. In another aspect, each laser includes a waveguide having a left sidewall grating and a right sidewall grating, the effective widths of the waveguides of the first laser and the second laser are different, and the offset between the left sidewall grating and the right sidewall grating of the second laser is different from the offset between the left sidewall grating and the right sidewall grating of the first laser. The integrated laser arrays described herein can be particularly suitable for implementation in dense wavelength division multiplexed (DWDM) systems, but can also be used in other systems that require laser arrays.

[0017] The systems, methods, and devices of the present disclosure each have several innovative aspects, and it is not only a single one of these aspects that is the cause of all the desired attributes disclosed herein. Details of one or more implementations of the subject matter described in this specification are set forth in the following description and the accompanying drawings.

[0018] To illustrate the purpose of the integrated laser arrays described herein, it may be useful to first understand the phenomena that may be operative in some of the systems in which integrated laser arrays can be used. The following basic information can be considered as a basis upon which the present disclosure can be appropriately explained. Such information is provided for purposes of explanation only and should not be construed in any way as limiting the broad scope of the present disclosure and its potential applications.

[0019] Generally, lasers use direct bandgap semiconductor materials such as gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), or other group III-V semiconductors (i.e., semiconductors based on group III and group V elements of the periodic table) to emit light. Direct bandgap semiconductors are more suitable for efficient and coherent light emission compared to indirect bandgap semiconductor materials such as silicon (Si). However, semiconductor materials that may not be optimal for light generation may be preferred for light transmission and manipulation, of which Si is the most prominent example. For example, Si can be used to fabricate waveguides, gratings, wavelength synthesizers, or other components of a photonic integrated circuit (PIC).

[0020] Emerging silicon photonics (SiPh)-based optical input / output (I / O) technologies require multi-wavelength laser sources to support the high data rates of advanced optical communication and computing applications. These multi-wavelength lasers are a key part of optical transmitters and are expected to improve in terms of performance, efficiency, cost, and bandwidth scaling. However, meeting the strict wavelength spacing and power uniformity requirements of lasers is extremely challenging. One conventional method of providing multi-wavelength lasers is to employ an array of III-V lasers fabricated in a III-V manufacturing facility. Another conventional method involves using comb lasers such as Fabry-Perot and mode-locked multi-wavelength comb lasers. Both of these methods have limitations. For example, one limitation of the first method is that III-V manufacturing facilities are generally not equipped with the advanced tools used in Si manufacturing facilities, resulting in limited lithography for different lasers that can be used to fabricate the laser array, thereby resulting in poor channel and power uniformity of the laser array. For the second method, although the wavelength spacing of the comb lasers can be uniform, the number of wavelengths and power uniformity may be difficult to control, resulting in power waste and unequal power distribution across different wavelength channels. In addition, the channel spacing of the comb lasers is based on the cavity length, which may make it difficult to obtain a wider channel spacing.

[0021] This disclosure relates to integrated lasers, integrated laser arrays, photonic devices, packages, and systems that are designed to address one or more of the above challenges. A laser or laser array can be described as "integrated" if the component responsible for emitting light (e.g., a III-V component) of the laser or laser array is implemented on a single support (e.g., a chip, wafer, die, or substrate) as the component responsible for transporting and / or manipulating light (e.g., a waveguide, grating, or modulator). The individual lasers of a laser array can include a light emitter structure (sometimes also referred to as the "active region") and a waveguide, both of which are arranged along the longitudinal axis of the laser / waveguide / light emitter structure. The light emitter structure can be used to emit light of a specific wavelength. The waveguide can be used to transport the light emitted by the light emitter structure (e.g., transport the light from the light emitter structure to the laser output). A grating can be disposed on the top / bottom surface and / or sidewalls of the waveguide to change the wavelength of the light emitted by the light emitter structure to another wavelength as the light travels through the waveguide. The wavelength spacing between different lasers of a laser array can be defined with high precision by changing the effective pitch of the gratings of different lasers and / or by changing the effective width (and thus the effective refractive index) of the waveguides of different lasers. Specifically, some embodiments of the present disclosure are based on using techniques that allow for achieving sub-nanometer effective pitch resolution of gratings even when the gratings are fabricated with a resolution of one nanometer or higher to implement different lasers of a laser array. Other embodiments of the present disclosure are based on using techniques that include making the effective widths of different lasers different by implementing sidewall gratings on the left and right sidewalls of a laser waveguide and changing the offset between the sidewall grating on the left sidewall and the sidewall grating on the right sidewall from one laser to another to compensate for the change in grating intensity caused by the change in the effective widths of different lasers. In some embodiments, these two techniques can be combined. A laser array formed according to one or a combination of the techniques described herein can be an integrated laser array because the light emitter structures of different lasers can be or can include III-V components, while the waveguides and gratings can be Si components. As used herein, the term "Si component" refers to a component made of any material other than III-V materials, where Si is a non-limiting example of such materials. Compared to conventional methods of using III-V components to achieve wavelength control (e.g., control the wavelength spacing of the emitted light), using Si components to achieve wavelength control (e.g., control the wavelength spacing after the light has been emitted) can advantageously allow for more stringent control of the laser channel spacing and power. The integrated laser arrays described herein can be particularly suitable for implementation as integrated DWDM laser arrays.An integrated laser array as described herein can be implemented as a multi-wavelength laser array on Si, where the channel spacing conforms to the CW wavelength division multiplexing (WDM) MSA (continuous wave wavelength division multiplexing multi-source agreement) standard, can include Si components in the form of an array of ring modulators for a multi-channel transmitter, and can be included in a transmitter architecture having an integrated laser and ring modulator. In some embodiments, the entire optical transmission system with an integrated laser array as described herein can be implemented on a single support (e.g., on a single Si chip), which can eliminate the need for an expensive and lossy coupling between the laser array and a separate transmitter chip.

[0022] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like numerals indicate like parts throughout, and by way of illustration, embodiments are shown that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Accordingly, the following detailed description should not be taken in a limiting sense.

[0023] Any one of the features discussed with reference to any one of the drawings herein can be combined with any other feature to suitably form the photonic device 100, the laser array 110, the laser 112, the microelectronic package 2200, or the computing device 2400. For convenience, the phrase "lasers 112" may be used to refer to a collection of lasers 112-1, 112-2, etc., while the phrase "laser 112" may be used to refer to one of the lasers 112. Similarly, the phrase "modulators 122" may be used to refer to a collection of modulators 122-1, 122-2, etc., while the phrase "modulator 122" may be used to refer to one of the modulators 122, etc. Further, for convenience, a collection of drawings identified by letters in their reference numerals may be referred to without the letters, e.g., Figures 2A - 2B the collection can be referred to as "Figure 2", Figures 3A - 3BThe set can be referred to as "Figure 3", and so on. Multiple elements of the drawings with the same reference numerals can be shared between different drawings; for the sake of convenience in discussion, the description of these elements provided for one of the drawings is not repeated for the other drawings, and these elements can take the form of any of the embodiments disclosed herein. The drawings are not necessarily drawn to scale. Although some of the drawings in the figures show linear structures with flat walls / surfaces and right-angled corners, this is only for ease of illustration and may not reflect real-life process limitations. When examining any of the structures described herein using, for example, scanning electron microscopy (SEM) images or transmission electron microscope (TEM) images, real-life process limitations may cause various features to appear less "ideal". In such images of real structures, possible processing defects may also be visible, for example, non-perfectly straight edges of materials, tapered vias, trenches or other openings, unintentional rounding of corners, or thickness variations of different material layers. There may be other defects not listed here but common in the field of semiconductor device manufacturing and packaging. Inspection of layout and mask data for reconstructing circuits using, for example, optical microscopy, TEM, or SEM, and reverse engineering of parts of the device, and / or inspection of cross-sections of the device for detecting the shape and position of various device elements using, for example, Physical Failure Analysis (PFA) will allow determination of the presence of the integrated laser array as described herein.

[0024] For the purposes of this disclosure, the phrase "A and / or B" means (A), (B), or (A and B). For the purposes of this disclosure, the phrase "A, B, and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C). When used to describe a dimension range, the phrase "between X and Y" represents a range that includes X and Y. When used to describe the position of an element, the phrase "between X and Y" represents the region spatially between element X and element Y. As described herein or as known in the art, based on the context of a particular value, the terms "substantially", "close to", "about", "near", and "approximate" generally mean within + / - 20% of the target value, for example, within + / - 5% or within + / - 2%. Similarly, as described herein or as known in the art, based on the context of a particular value, terms indicating the orientation of various elements, for example, "coplanar", "perpendicular", "orthogonal", "parallel", or any other angle between elements, generally mean within + / - 10% of the exact orientation, for example, within + / - 5% or within + / - 2%.

[0025] This specification uses the phrases "in an embodiment" or "in embodiments", each of which can refer to one or more of the same or different embodiments. Additionally, terms such as "comprising", "including", "having", etc. as used with respect to the embodiments of the present disclosure are synonymous. As used herein, the terms "package" and "integrated circuit (IC) package" are synonymous, and the terms "die" and "IC die" are also synonymous. Additionally, the terms "chip", "dielet", "die", and "IC die" may be used interchangeably herein.

[0026] Although certain elements may be referred to in the singular herein, such elements can include multiple sub-elements. For example, "dielectric material" can include one or more dielectric materials, or "insulating material" can include one or more insulating materials. The terms "oxide", "carbide", "nitride", etc. refer to compounds containing oxygen, carbon, nitrogen, etc., respectively. The term "high-k dielectric" refers to a material having a higher dielectric constant than silicon dioxide; while the term "low-k dielectric" refers to a material having a lower dielectric constant than silicon dioxide. Unless otherwise specified, the term "insulate" and its variants (e.g., "insulated" or "insulator") mean "electrically insulated", and the term "conductive" and its variants (e.g., "conducting" or "conductor") mean "electrically conductive". For optical signals and / or for devices, components, and elements that operate on or with optical signals, the term "conduct" can also mean "optically conduct". The term "insulating material" refers to a solid material that is substantially non-conductive (and / or a liquid material that cures after processing as described herein). By way of example and not limitation, they can include organic polymers and plastics, as well as inorganic materials such as ionic crystals, ceramics, glass, silicon, and alumina or combinations thereof. They can include dielectric materials, highly polarizable materials, and / or piezoelectric materials. Without departing from the scope of the present disclosure, they can be transparent or opaque. Further examples of insulating materials are underfills and molding or molding-like materials used in packaging applications, including, for example, materials used in organic interposers, package supports, and other such components.

[0027] Figure 1 is a schematic diagram of an example photonic device 100 having an integrated laser array according to various embodiments. As Figure 1 shown, the photonic device 100 can include a laser array 110 and a modulator array 120. Also as Figure 1 shown, the photonic device 100 can further include an N×M multiplexer 130 located between the laser array 110 and the modulator array 120, where N is the number of inputs of the multiplexer 130, M is the number of outputs of the multiplexer 130, and N and M are integers greater than 1.

[0028] The laser array 110 may include N lasers 112, shown respectively as lasers 112-1, lasers 112-2, lasers 112-3, and lasers 112-4 in Figure 1 . Thus, for the example of Figure 1 , N is equal to 4. However, although the laser array 110 shown in Figure 1 and subsequent figures shows a certain number of lasers 112 (e.g., four lasers 112 are shown in Figure 1 , while three lasers 112 are shown in Figures 5 - 9 ), in various embodiments, the laser array 110 and / or the photonic device 100 may include any number N of two or more lasers 112. Each of the lasers 112-i is configured to output light of a specific different wavelength λ i , where i is an integer between 1 and N identifying one of the N lasers 112. For example, laser 112-1 may output light of wavelength λ 1 , which is provided as an optical signal 111-1 at the output of laser 112-1. Laser 112-2 may output light of wavelength λ 2 , which is provided as an optical signal 111-2 at the output of laser 112-2. Laser 112-3 may output light of wavelength λ 3 , which is provided as an optical signal 111-3 at the output of laser 112-3. Laser 112-4 may output light of wavelength λ 4 , which is provided as an optical signal 111-4 at the output of laser 112-4. The N inputs of the multiplexer 130 may be based on the N optical signals 111 provided at the outputs of the N lasers 112 of the laser array 110, as shown in Figure 1 . In some embodiments, the spacing between the wavelengths λ of the outputs 111 of different lasers 112 may be in the range of about 1 angstrom to about 50 nanometers, e.g., from sub-nanometer to about 30 nanometers, or between about 1 nanometer and 20 nanometers. In some embodiments, the wavelengths λ of different lasers 112 may be in the range between about 1100 nanometers and about 1700 nanometers, e.g., about 1300 nanometers or about 1550 nanometers. In the context of the present disclosure, a laser 112-i that outputs light of a specific wavelength λ i may include a laser 112-i that outputs light within a range of wavelengths, where the wavelength λ i is the center wavelength of the range. In some embodiments, one or more of the lasers 112 may be implemented as distributed Bragg reflector (DBR) lasers (e.g., as shown in Figure 2A , Figure 3A andFigure 4A as shown in). In some embodiments, one or more of the lasers 112 may be implemented as distributed feedback (DFB) lasers (e.g., as shown in Figure 2B , Figure 3B and Figure 4B ).

[0029] The multiplexer 130 may be an N×M combiner and splitter. To this end, the multiplexer 130 may be configured to combine N optical signals 111 of different wavelengths λ 1 to λ N provided as N inputs to the multiplexer 130 into a single optical signal as a multi-wavelength signal (i.e., a signal including wavelengths λ 1 -λ N ). Then, the multiplexer 130 may provide the optical signal 131 at M outputs of the multiplexer 130. The optical signals 131 provided at the M outputs of the multiplexer 130 are separately shown as optical signals 131-1, optical signals 131-2, optical signals 131-3, and optical signals 131-4 in Figure 1 . Thus, for the example of Figure 1 , M is equal to 4. However, although Figure 1 illustrates four output signals 131 at the output of the multiplexer 130, in various embodiments, the photonic device 100 may include any number M of two or more output signals 131 output by the multiplexer 130. Each of the optical signals 131-j provided at the M outputs of the multiplexer 130 (where j is an integer between 1 and M) may be a corresponding portion of the multi-wavelength signal having wavelengths λ 1 -λ N combined from the N optical signals 111 provided at the N inputs of the multiplexer 130. Thus, the multiplexer 130 may combine N optical signals 111 of different wavelengths λ 1 to λ N into a single optical signal that is a multi-wavelength signal including wavelengths λ 1 -λ N , and then divide the single optical signal into M optical signals 131-j provided at the M outputs of the multiplexer 130. In various embodiments, the number M of outputs of the multiplexer 130 may be equal to but not necessarily equal to the number N of inputs of the multiplexer 130. By separately showing the wavelength functions of the outputs 111-1 to 111-4 using a dashed line, a dotted line, a dash line, and a solid line, Figure 1Schematically shows that each of the outputs 111 of the laser 112 is an output having a single center wavelength. By showing the wavelength function for the output 111-1 to 111-4 of one optical signal combined into the signal 131-1, and by labeling each of the other signals 131 as the signal λ 1 -λ 4 (so as not to clutter the drawings), Figure 1 Further schematically shows that each of the optical signals 131 is a signal that combines (e.g., superimposes) the optical signals 111 of different wavelengths λ 1 to λ N .

[0030] The modulator array 120 may include a modulator arrangement 121 (e.g., a series of N modulators 122) of N modulators 122 for each signal branch at the output of the multiplexer 130 (i.e., in the path of each of the optical signals 131). The respective modulator arrangements 121 are labeled as modulator arrangement 121-1, modulator arrangement 121-2, modulator arrangement 121-3, and modulator arrangement 121-4 in Figure 1 . The number of modulator arrangements 121 may be equal to the number M of the outputs of the multiplexer 130. The number of modulators 122 within the modulator arrangement 121 of a given branch of the modulator array 120 may be equal to the number N of the inputs of the multiplexer 130. The modulator arrangement 121 of a given branch of the modulator array 120 may include N modulators 122, in Figure 1are separately labeled as modulator 122-1, modulator 122-2, modulator 122-3, and modulator 122-4. For a given optical signal 131-j, the modulator 122-i of the modulator arrangement 121-j is configured to modulate a portion of the optical signal 131-j that corresponds to the optical signal 111-i and is provided as an input to the modulator arrangement 121-j. For example, for the optical signal 131-2, the modulator 122-1 of the modulator arrangement 121-2 is configured to modulate a portion of the optical signal 131-2 that corresponds to the optical signal 111-1 and is provided as an input to the modulator arrangement 121-2, the modulator 122-2 of the modulator arrangement 121-2 is configured to modulate a portion of the optical signal 131-2 that corresponds to the optical signal 111-2, the modulator 122-3 of the modulator arrangement 121-2 is configured to modulate a portion of the optical signal 131-2 that corresponds to the optical signal 111-3, and the modulator 122-4 of the modulator arrangement 121-2 is configured to modulate a portion of the optical signal 131-2 that corresponds to the optical signal 111-4. In some embodiments, there may be a one-to-one correspondence between the lasers 112 and the modulators 122 in each of the modulator arrangements 121, because for a given modulator arrangement 121-j, each laser 112 is associated with one and only one modulator 122, and each modulator 122 is associated with one and only one modulator 112.

[0031] Within a given modulator arrangement 121-j of the modulator array 120, the modulator 122 can apply modulation to different wavelengths generated by the laser 112 to generate a modulator output signal 123 that includes a combination (e.g., superposition) of signals having different wavelengths λ 1 -λ N . In some embodiments, the modulator 122 can be a wavelength-selective modulator, which means that the modulator 122-i can receive an optical signal that includes multiple center wavelengths (e.g., wavelengths λ 1 -λ 4 ) as an input, but only apply modulation to a portion of the optical signal whose carrier wavelength is the carrier wavelength of the output signal 111-i of the associated laser 112-i. For example, for a given modulator arrangement 121-j, the modulator 122-1 can receive the wavelength synthesizer output 131-j as a combination of optical signals corresponding to wavelengths λ 1 -λ 4 (when N = 4) as an input, apply modulation to the portion of the wavelength synthesizer output 131-j that corresponds to the wavelength λ of the optical signal 111-1 1 to generate a portion of the wavelength synthesizer output 131-j that corresponds to the wavelength λ 1a corresponding modulated portion, and causes the wavelength synthesizer output 131-j to pass, without modulation, a portion corresponding to wavelength λ 2 -λ 4 corresponding (e.g., corresponding to optical signals 111-2 to 111-4). Thus, the modulator output 123-1 of modulator 122-1 of a given modulator arrangement 121-j is a combination of the modulated portion of the wavelength synthesizer output 131-j corresponding to wavelength λ 1 corresponding and the unmodulated portion of the wavelength synthesizer output 131-j corresponding to wavelength λ 2 -λ 4 corresponding. Thereafter, modulator 122-2 may receive the modulator output 123-1 from modulator 122-1 as an input, apply modulation to the portion of the wavelength synthesizer output 131-j corresponding to the wavelength λ of optical signal 111-2 to generate a modulated portion of the wavelength synthesizer output 131-j corresponding to wavelength λ 2 corresponding, and cause the wavelength synthesizer output 131-j to pass, without modulation, a portion corresponding to wavelength λ 2 corresponding and cause the wavelength synthesizer output 131-j to pass, without modulation, a portion corresponding to wavelength λ 3 -λ 4 corresponding (e.g., corresponding to optical signals 111-3 to 111-4), and cause the wavelength synthesizer output 131-j to pass, without modulation, the modulated portion corresponding to the wavelength λ generated by modulator 122-1. Thus, the modulator output 123-2 of modulator 122-2 is a combination of: the modulated portion of the wavelength synthesizer output 131-j corresponding to the wavelength λ generated by modulator 122-1 1 corresponding, the modulated portion of the wavelength synthesizer output 131-j corresponding to the wavelength λ generated by modulator 122-2 1 corresponding, and the unmodulated portion of the wavelength synthesizer output 131-j corresponding to wavelength λ 2 corresponding. In other words, the modulator output 123-2 of modulator 122-2 is a combination of: the unmodulated portion of modulator output 123-1 corresponding to wavelength λ 3 corresponding, the modulated portion of the wavelength synthesizer output 131-j corresponding to the wavelength λ generated by modulator 122-2 4 corresponding, the unmodulated portion of the wavelength synthesizer output 131-j corresponding to wavelength λ 1 corresponding, and the unmodulated portion of the wavelength synthesizer output 131-j corresponding to wavelength λ 2 corresponding. Next, modulator 122-3 may receive the modulator output 123-2 from modulator 122-2 as an input, apply modulation to the portion of the wavelength synthesizer output 131-j corresponding to the wavelength λ of optical signal 111-3 3 corresponding, and cause the wavelength synthesizer output 131-j to pass, without modulation, a portion corresponding to wavelength λ 4 corresponding. Next, modulator 122-3 may receive the modulator output 123-2 from modulator 122-2 as an input, apply modulation to the portion of the wavelength synthesizer output 131-j corresponding to the wavelength λ of optical signal 111-33 The corresponding partial application is modulated to generate a wavelength synthesizer output 131-j corresponding to the wavelength λ 3 The corresponding modulated portion, and the portion corresponding to the wavelength λ of the wavelength synthesizer output 131-j passes through without modulation (e.g., corresponding to the optical signal 111-4), and the portion corresponding to the wavelength λ generated by the modulator 122-1 of the wavelength synthesizer output 131-j passes through without modulation 4 The corresponding modulated portion, and the portion corresponding to the wavelength λ generated by the modulator 122-2 of the wavelength synthesizer output 131-j passes through. Thus, the modulator output 123-3 of the modulator 122-3 is a combination of the following: the modulated portion corresponding to the wavelength λ generated by the modulator 122-1 of the wavelength synthesizer output 131-j 1 The corresponding modulated portion, and the portion corresponding to the wavelength λ generated by the modulator 122-3 of the wavelength synthesizer output 131-j passes through. Thus, the modulator output 123-3 of the modulator 122-3 is a combination of the following: the modulated portion corresponding to the wavelength λ generated by the modulator 122-1 of the wavelength synthesizer output 131-j 2 The corresponding modulated portion, and the portion corresponding to the wavelength λ generated by the modulator 122-2 of the wavelength synthesizer output 131-j 1 The corresponding modulated portion, and the portion corresponding to the wavelength λ generated by the modulator 122-3 of the wavelength synthesizer output 131-j 2 The corresponding modulated portion, and the portion corresponding to the wavelength λ of the wavelength synthesizer output 131-j 3 The corresponding unmodulated portion. In other words, the modulator output 123-3 of the modulator 122-3 is a combination of the following: the unmodulated portion corresponding to the wavelength λ of the modulator output 123-1 4 The corresponding unmodulated portion, the unmodulated portion corresponding to the wavelength λ of the modulator output 123-2 1 The corresponding unmodulated portion, the modulated portion corresponding to the wavelength λ generated by the modulator 122-3 of the wavelength synthesizer output 131-j 2 The corresponding modulated portion, and the portion corresponding to the wavelength λ of the wavelength synthesizer output 131-j 3 The corresponding unmodulated portion. Finally, the modulator 122-4 can receive the modulator output 123-3 from the modulator 122-3 as an input, and apply modulation to the portion corresponding to the wavelength λ of the wavelength synthesizer output 131-j and the optical signal 111-4 to generate a wavelength synthesizer output 131-j corresponding to the wavelength λ 4 The corresponding modulated portion, and the portion corresponding to the wavelength λ of the modulator output 123-3 passes through without modulation 4 The corresponding modulated portion, and the portion corresponding to the wavelength λ of the wavelength synthesizer output 131-j 4 The corresponding modulated portion, and the portion corresponding to the wavelength λ of the modulator output 123-3 passes through without modulation 1 -λ 3 The corresponding modulated portion, and the portion corresponding to the wavelength λ generated by the modulator 122-1 of the wavelength synthesizer output 131-j 1 The corresponding modulated portion, and the portion corresponding to the wavelength λ generated by the modulator 122-2 of the wavelength synthesizer output 131-j2 The corresponding modulated portion, the output 131-j of the wavelength synthesizer, and the wavelength λ generated by the modulator 122-3 3 The corresponding modulated portion, and the output 131-j of the wavelength synthesizer, and the wavelength λ generated by the modulator 122-4 4 The corresponding modulated portion. In other words, the modulator output 123-4 of the modulator 122 is a combination of the following: the unmodulated portion of the modulator output 123-1 corresponding to the wavelength λ 1 The corresponding unmodulated portion, the unmodulated portion of the modulator output 123-2 corresponding to the wavelength λ 2 The corresponding unmodulated portion, the unmodulated portion of the modulator output 123-3 corresponding to the wavelength λ 3 The corresponding unmodulated portion, and the output 131-j of the wavelength synthesizer, and the wavelength λ generated by the modulator 122-4 4 The corresponding modulated portion.

[0032] Different ways of implementing the modulator 122 are known in the art, and all of these ways are within the scope of the present disclosure. For example, in some embodiments, the modulator 122 can be implemented as a ring modulator, for example, as a wavelength-selective ring modulator. Different ways of implementing the multiplexer 130 are known in the art, and all of these ways are within the scope of the present disclosure. For example, in some embodiments, the multiplexer 130 can include a Mach-Zehnder interferometer (MZI). In some embodiments, one or more of the modulator 122 and / or the multiplexer 130 can be implemented as Si components.

[0033] Embodiments of the present disclosure can be formed or executed on any suitable support 102 (such as a substrate, die, wafer, or chip). The support 102 can be, for example, the wafer 2100 discussed below Figure 11 and can be a die or included in a die, such as the die discussed below Figure 11The separated die 2102. The support 102 can be a semiconductor substrate composed of a semiconductor material system including, for example, an N-type material system or a P-type material system. In one implementation, the semiconductor substrate can be a crystalline substrate formed using bulk silicon or a silicon-on-insulator (SOI) substructure. In other implementations, the semiconductor substrate can be formed using alternative materials, which may or may not be combined with silicon, and these alternative materials include, but are not limited to, germanium, silicon germanium, indium antimonide, lead telluride, indium arsenide, indium phosphide, gallium arsenide, aluminum gallium arsenide, aluminum arsenide, indium aluminum arsenide, indium gallium arsenide, gallium nitride, indium gallium nitride, aluminum indium nitride or gallium antimonide, or other combinations of III-V materials, II-VI materials (i.e., materials from groups II and VI of the periodic table) or IV-group materials (i.e., materials from group IV of the periodic table). In some embodiments, the substrate can be amorphous. In some embodiments, the support 102 can be a printed circuit board (PCB) substrate, a package substrate, an interposer, a wafer or a die. In some embodiments, the support 102 can be or can include a glass core. As used herein, the term "glass core" refers to a structure of any glass material (e.g., a portion of a glass layer), such as quartz, silica, fused silica, silicate glass (e.g., borosilicate, aluminosilicate, aluminoborosilicate), soda-lime glass, soda-lime silica, borofloat glass, lead borate glass, photosensitive glass, non-photosensitive glass or glass-ceramics. In particular, the glass core can refer to a bulk glass or a solid volume of glass, as opposed to a material that may include glass particles (such as a glass fiber reinforced polymer). Such glass materials are typically amorphous, usually transparent amorphous solids. In some embodiments, the glass core can be an amorphous solid glass layer. In some embodiments, the glass core can include silicon and oxygen, and any one or more of aluminum, boron, magnesium, calcium, barium, tin, sodium, potassium, strontium, phosphorus, zirconium, lithium, titanium and zinc. In some embodiments, the glass core can include a material, such as any of the above materials, where the weight percentage of silicon is at least about 0.5%, e.g., between about 0.5% and 50%, between about 1% and 48%, or at least about 23%. For example, if the glass core is fused silica, the weight percentage of silicon can be about 47%. In some embodiments, the glass core can include at least 23% silicon and at least 26% oxygen by weight, and in some further embodiments, such a glass core can further include at least 5% aluminum by weight. In some embodiments, the glass core can include any of the above materials and can further include one or more additives, such as aluminum and oxygen (e.g., Al 2 O 3 ), boron and oxygen (e.g., B 2 O3 ), magnesium and oxygen (e.g., MgO), calcium and oxygen (e.g., CaO), strontium and oxygen (e.g., SrO), barium and oxygen (e.g., BaO), tin and oxygen (e.g., SnO 2 ), sodium and oxygen (e.g., Na 2 O), potassium and oxygen (e.g., K 2 O), phosphorus and oxygen (e.g., P 2 O 3 ), zirconium and oxygen (e.g., ZrO 2 ), lithium and oxygen (e.g., Li 2 O), titanium (e.g., Ti) and zinc (Zn). Although some examples of materials that can form the support 102 are described herein, any material that can be used as a basis on which an integrated laser array as described herein can be built falls within the spirit and scope of the present disclosure.

[0034] In some embodiments, the lasers 112 of the laser array 110 can be implemented on a single support 102. In some embodiments, the modulator 122 and the multiplexer 130 can be implemented on the same support 102 as the laser 112, as Figure 1 shown. However, in other embodiments, one or more of the modulator 122 and / or the multiplexer 130 can be implemented on a support different from the support 102 having the laser 112.

[0035] The photonic device 100 can be particularly advantageous when used as part of a DWDM system, but is not limited to DWDM systems. As Figure 1 shown, the arrangement of the multiplexer 130, the modulator array 120, and the various modulators 122 of the photonic device 100 is not the only arrangement in which an integrated laser array 110 as described herein can be implemented, but only provides an example of such a photonic device. Figure 1 The number and position of the various elements as shown are illustrative only, and in various other embodiments, other numbers of these elements can be used in other positions relative to each other.

[0036] Turning to the details of the integrated laser array 110, the description of these details is arranged as follows. First, FIGS. 2 - 4 illustrate examples of lasers of different types and having different types of gratings. In particular, two different types of lasers are illustrated, one being a DBR laser as Figure 2A 、 Figure 3A and Figure 4A shown, and the other being a DFB laser as Figure 2B 、 Figure 3B and Figure 4B shown. The different types of gratings shown in FIGS. 2 - 4 are as Figures 2A - 2BSurface gratings for two different types of lasers, such as Figures 3A - 3B Sidewall gratings for two different types of lasers, as shown in Figures 4A - 4B Surface and sidewall gratings for two different types of lasers, as shown in Figure 2A , Figure 2B , Figure 3A , Figure 3B , Figure 4A and Figure 4B Each of which in shows an example of a laser that can be any one of the lasers 112 of the laser array 110. On the other hand, Figures 5 - 1 Each of which in 0 shows an example of a laser array 110 having three lasers 112 (individually labeled lasers 112-1, 112-2, and 112-3) in order to show the differences between the different lasers 112 of the laser array 110. In particular, Figures 5 - 7 shows lasers 112-1 to 112-3 having surface gratings with different effective pitches, while Figures 8 - 1 0 shows lasers 112-1 to 112-3 having sidewall gratings and waveguides with different effective widths. In a further embodiment, the lasers 112 of the laser array 110 can be implemented with surface gratings having different effective pitches as shown in Figures 5 - 7 and sidewall gratings and waveguides having different effective widths as shown in Figures 8 - 1 0. Examples of such embodiments as shown in Figure 4A , Figure 4B are for DBR lasers and DFB lasers, respectively.

[0037] Figures 2A - 2B is a top view of two example lasers having surface gratings according to various embodiments. Figure 2A shows a laser 200A as an example of a DBR laser having a surface grating, while Figure 2B shows a laser 200B as an example of a DFB laser having a surface grating. Lasers 200A and 200B can be collectively referred to as "laser 200", and each laser is an example implementation of any one of the lasers 112 of the laser array 110 described herein.

[0038] As Figures 2A - 2B shown, the laser 200 can include: a waveguide 140 having a backside terminal 142 at one end and an output 144 at the other end; an optical emitter structure 150 aligned along the longitudinal axis of the waveguide 140; and at least one of a rear grating 160-1 and a front grating 160-2, also aligned along the longitudinal axis of the waveguide 140. Figures 2A - 2Band FIGS. 3-10 illustrate a coordinate system x-y-z to describe different directions and planes in accordance with the directions and planes of the same coordinate system. As used herein, the x-axis is the axis along which the longitudinal axis of the waveguide 140 extends and is also the direction of light propagation through the waveguide 140 (e.g., in Figures 2A - 2B the arrow representing the optical signal 111 output by the laser 200 can also be regarded as the longitudinal axis of the waveguide 140). In addition, as used herein, the x-y plane is the plane of the top view of the laser shown in FIGS. 2-10, and the x-z plane is the plane of the cross-sectional side view of the laser shown in FIGS. 2-10.

[0039] The optical transmitter structure 150 is shown in Figures 2A to 2B as a translucent structure superimposed above the waveguide 140 to indicate that in some embodiments, the optical transmitter structure 150 can be disposed above the waveguide 140 (i.e., further away from the support on which the waveguide 140 is disposed, such as the support 102 described above), while in other embodiments, the optical transmitter structure 150 can be disposed below the waveguide 140 (i.e., closer to the support on which the waveguide 140 is disposed). As Figures 2A - 2B shown, in some embodiments, the longitudinal axis of the waveguide 140 can be parallel to the longitudinal axis of the optical transmitter structure 150. Generally, the optical transmitter structure 150 can include any structure known in the art that can emit light in a laser. For example, in some embodiments, the optical transmitter structure 150 can include an active region configured to emit light of a specific wavelength, e.g., an active region including III-V materials. Thus, such an optical transmitter structure 150 can be an example of a III-V component. In some embodiments, the optical transmitter structures 150 of different lasers 112 of the laser array 110 can emit light of approximately the same wavelength, and the grating 160 can be used to change the wavelength of the emitted light such that the wavelengths λ of the outputs 111 of different lasers 112 are different. In other embodiments, the optical transmitter structures 150 of at least some of the lasers 112 in the laser array 110 can emit light of different wavelengths. In such embodiments, the grating 160 can still be used to change the wavelength of the emitted light.

[0040] The waveguide 140 can be any waveguide configured to support the propagation of light emitted by the optical transmitter structure 150 between the backside terminal 142 and the output 144 such that the laser 200 can output the optical signal 111 from the output 144. Generally, the waveguide 140 can include any waveguide structure known in the art that can support the propagation of light in a laser. For example, in some embodiments, the waveguide 140 can include an insulator / dielectric material, e.g., a material including a semiconductor material (e.g., Si) and nitrogen (N), e.g., SiN. Thus, such a waveguide 140 can be an example of a Si component.

[0041] As used herein, the terms "top surface" and "bottom surface" of waveguide 140 refer to the boundaries / faces of the waveguide that are substantially parallel to the support member, above which a laser having the waveguide 140 is disposed (e.g., the support member 102 as described above). For example, the top surface and the bottom surface of waveguide 140 can be two surfaces of the waveguide 140 that are in two different (opposite) x-y planes of an exemplary coordinate system. The top surface and the bottom surface of waveguide 140 can also be referred to as the top "face" and the bottom "face" of waveguide 140. Figures 2A - 2B And some of the subsequent figures illustrate the top surface as surface 146. On the other hand, the term "sidewall" of waveguide 140 refers to the boundary / face that extends between the top surface and the bottom surface of waveguide 140 and is substantially parallel to the longitudinal axis of waveguide 140. For example, the sidewalls of waveguide 140 can be two surfaces of the waveguide 140 that are in two different (opposite) x-z planes of an exemplary coordinate system. Figures 2A - 2B And some of the subsequent figures show the sidewalls of waveguide 140 as left sidewall 148-1 and right sidewall 148-2 (collectively referred to as "sidewalls 148"). It should be noted that in some embodiments, the sidewalls 148 may not necessarily be in a plane perpendicular to the support member 102. For example, due to the manufacturing process for manufacturing waveguide 140, the sidewalls 148 can be tapered. Thus, the sidewalls 148 can be described as such surfaces of waveguide 140: the surfaces are parallel to the longitudinal axis of waveguide 140 (i.e., parallel to the propagation direction of light through waveguide 140) and do not extend parallel to the support member 102 on which the laser is disposed. It should be noted that all the descriptions provided herein regarding the gratings on the top surface 146 equally apply to the gratings disposed on the bottom surface of waveguide 140.

[0042] As used herein, the term "width" of waveguide 140 refers to the distance between the first sidewall and the second sidewall of waveguide 140, e.g., the dimension of waveguide 140 in a direction parallel to the support member 102 and perpendicular to the longitudinal axis of waveguide 140 (e.g., the dimension of waveguide 140 measured along the y-axis of the exemplary coordinate system shown in this figure). As used herein, the term "length" of waveguide 140 refers to the dimension of waveguide 140 in the direction of the longitudinal axis of waveguide 140, e.g., the dimension of waveguide 140 in a direction parallel to the support member 102 and parallel to the propagation direction of light through waveguide 140 (e.g., the dimension of waveguide 140 measured along the x-axis of the exemplary coordinate system shown in this figure). As used herein, the term "thickness" of waveguide 140 refers to the distance between the top surface and the bottom surface of waveguide 140, e.g., the dimension of waveguide 140 in a direction perpendicular to the support member (e.g., the dimension of waveguide 140 measured along the z-axis of the exemplary coordinate system shown in this figure).

[0043] The gratings 160-1 and 160-2 (collectively referred to as "gratings 160") can be disposed on the top surface and / or the bottom surface of the waveguide 140 to modify the wavelength of the light emitted by the light emitter structure 150 such that the optical signal 111 emerging from the output 144 has the desired wavelength of the laser 200. In some embodiments, the gratings 160 can be used to modify the phase of the light emitted by the light emitter structure 150 such that the optical signal 111 emerging from the output 144 has the desired phase of the laser 200. Lasers 200A and 200B differ in terms of the position of the gratings relative to the light emitter structure 150. In particular, for a DBR laser as shown by laser 200A, the gratings 160-1 and 160-2 can be disposed on portions of the waveguide 140 at either end of the light emitter structure 150, while for a DFB laser as shown by laser 200B, the gratings 160-1 and 160-2 can be disposed on portions of the waveguide 140 below or above the light emitter structure 150. In other words, for laser 200A, the footprint of the light emitter structure 150 (e.g., the projection on the x-y plane, or the plane on which the support for the laser is disposed) can at least partially or completely overlap with the footprint of the gratings 160, while for laser 200B, the footprint of the light emitter structure 150 can be adjacent (in a direction parallel to the longitudinal axis of the waveguide 140) to the footprint of the grating 160-1 and adjacent to the footprint of the grating 160-2. Although both gratings 160-1 and 160-2 are shown in Figures 2A - 2B , in some embodiments, as is known in the art, one of these gratings can be replaced with another reflective element (such as a mirror).

[0044] Generally, the gratings 160 can be a collection of perturbations 162 on the surface or sidewalls of the waveguide 140, as shown in Figures 2A - 2B . The perturbations 162 can be elongated perturbations, and each of the elongated perturbations 162 can extend in a direction substantially perpendicular to the longitudinal axis of the waveguide 140. In some embodiments, the perturbations 162 can be in the form of trenches, while in other embodiments, the perturbations 162 can be in the form of ridges. Figures 2A - 2B Illustrates an embodiment in which the grating 160 is a surface grating and thus the perturbations 162 are on the top surface 146 of the waveguide 140. Thus, Figures 2A - 2B the perturbations 162 of the waveguide 140 extend in the y-axis direction between the sidewalls 148-1 and 148-2.

[0045] Figures 3A - 3B is a top view of two example lasers with sidewall gratings according to various embodiments. Figure 3A Illustrates a laser 300A as an example of a DBR laser with a sidewall grating, while Figure 3BFIG. shows a laser 300B as an example of a DFB laser with sidewall gratings. Lasers 300A and 300B may be collectively referred to as "laser 300", and each laser is an example implementation of any one of the lasers 112 in the laser array 110 described herein. Lasers 300A and 300B are substantially the same as lasers 200A and 200B, respectively, but the grating 160 of laser 300 is a sidewall grating. Thus, in Figures 3A - 3B the perturbations 162 are located on the left sidewall 148-1 and the right sidewall 148-2 of the waveguide 140. Thus, Figures 3A - 3B the perturbations 162 of the waveguide 140 in Figures 8 - 1 extend in the z-axis direction between the bottom surface and the top surface 146 of the waveguide 140. In some embodiments of the sidewall grating, the perturbations 162 on one sidewall 148 may be offset relative to the perturbations 162 on the other sidewall 148 in a direction parallel to the longitudinal axis of the waveguide 140 (e.g., as shown by the offset 304 in

[0046] Figures 4A - 4B and described in more detail below). Figure 4A FIG. shows a laser 400A as an example of a DBR laser with a surface grating and a sidewall grating, while Figure 4B FIG. shows a laser 400B as an example of a DFB laser with a surface grating and a sidewall grating. Lasers 400A and 400B may be collectively referred to as "laser 400", and each laser is an example implementation of any one of the lasers 112 in the laser array 110 described herein. Lasers 400A and 400B are substantially the same as lasers 300A and 300B, respectively, but the grating 160 of laser 400 is the same sidewall grating as that of laser 300 and further extends partially on the top surface 146, similar to the grating 160 of laser 200. As shown in Figures 4A - 4B a first set 164-1 of perturbations 162 (which may be described as "first perturbations" or "first elongated perturbations") extends from a first line 166-1 on the top surface 146 of the waveguide 140 to the nearest edge (e.g., the top) of the first sidewall 148-1 in a direction perpendicular to the longitudinal axis of the waveguide 140 (in other words, the perturbations 162 of the first set 164-1 extend in a direction perpendicular to the propagation direction of the light emitted by the light emitter structure 150) and further extends from the nearest edge of the first sidewall 148-1 towards the opposite edge (e.g., the bottom) of the first sidewall 148-1, e.g., all the way down to the bottom surface of the waveguide 140. Similarly, as shown in Figures 4A - 4BAs shown, a second set 164-2 of perturbations 162 (which may be described as "second perturbations" or "second elongated perturbations") extends from a second line 166-2 on the top surface 146 of the waveguide 140 in a direction perpendicular to the longitudinal axis of the waveguide 140 to the nearest edge (e.g., the top) of the second sidewall 148-2 (in other words, the perturbations 162 of the second set 164-2 extend in a direction perpendicular to the direction of propagation of the light emitted by the light emitter structure 150) and further extends from the nearest edge of the second sidewall 148-2 towards the opposite edge (e.g., the bottom) of the second sidewall 148-2, e.g., all the way down to the bottom surface of the waveguide 140. In some embodiments, the first line 166-1 and / or the second line 166-2 may be substantially parallel to the longitudinal axis of the waveguide 140 and at a non-zero distance from each other. In some embodiments, the non-zero distance between the first line 166 and the second line 166 may be less than about 50% of the effective width of the waveguide, e.g., less than about 25% or less than about 10%. Similar to Figures 3A - 3B the grating 160, in Figures 4A - 4B the perturbations 162 of the second set 164-2 may be offset from the perturbations 162 of the first set 164-1 in a direction parallel to the longitudinal axis of the waveguide 140.

[0047] As described above, all descriptions provided herein regarding the grating on the top surface 146 apply equally to a grating provided on the bottom surface of the waveguide 140. This means Figures 2A - 2B can be considered to illustrate an embodiment of the laser 200 in which the perturbations 162 of the grating 160 are on the bottom surface of the waveguide 140 (i.e., closer to the surface of the support 102 than the top surface 146). This also means Figures 4A - 4B can be considered to illustrate an embodiment of the laser 400 that is substantially the same as the laser 300, in which the grating 160 of the laser 400 is the same sidewall grating as the grating of the laser 300, but in which the grating 160 further extends partially above the bottom surface of the waveguide 140, similar to the grating 160 of the laser 200 implemented on the bottom surface of the waveguide 140.

[0048] Conventionally, the elongated perturbations of a grating are periodic, which means that the pitch (e.g., the center-to-center distance between adjacent perturbations) is the same for all pairs of adjacent perturbations. The wavelength λ of a DBR or DFB laser depends on the pitch (Δ) of the grating on the waveguide and the effective refractive index (n eff ) of the waveguide and the surrounding medium, as described in the following equation: λ = 2n eff Δ

[0049] The variation of the laser wavelength can be mainly controlled by the grating pitch, and the difference in the output wavelengths of different lasers in the laser array can be controlled by the difference in pitch. Thus, the channel pitch is limited by the resolution of the fabricated laser pitch. For a 100 GHz channel pitch, the difference in pitch must be approximately 1 angstrom, which is difficult to achieve, if not impossible, even in the most advanced silicon manufacturing equipment. To avoid the requirement for sub-nanometer differences in grating pitch, a technique can be implemented that allows for sub-nanometer effective pitch resolution of the grating even when the grating is fabricated with a resolution of one nanometer or higher. In Figures 5 - 7 this technique is illustrated.

[0050] Figures 5 - 7 each of Figures 5 - 7 illustrates a laser array 110 as described above, where the laser array 110 includes three lasers 112. Again, the number of lasers 112 is merely exemplary here, and in other embodiments of the laser array 110 as described in reference Figures 5 - 7 the laser array 110 may include only two lasers 112 or more than three lasers 112. Only for each of the lasers 112 in Figures 5 - 7 are the waveguides 140 and gratings 160 shown in order to illustrate how differences in the gratings 160 are achieved for different lasers 112 without obscuring the drawings with details of other components of the lasers 112 (such as the optical emitter structure 150 or the backside terminal 142). For each laser 112 and Figures 5 - 7 in each of Figure 2A 、 Figure 3A and Figure 4A the portion of the waveguide 140 with the grating 160 as shown may be a portion of the waveguide 140 with a rear grating 160-1 or a portion of the waveguide 140 with a front grating 160-2 as described with reference to FIGS. 2 - 4, and may be implemented either adjacent to the optical emitter structure 150 as described in reference Figure 2A 、 Figure 3A and Figure 4A or may partially or fully overlap with the optical emitter structure 150 as described in reference Figure 2B 、 Figure 3B and Figure 4B . The grating 160 is described with reference to a surface grating implemented on the top surface 146 of the waveguide 140 in Figures 5 - 7 , but these descriptions apply equally to the grating 160 as a surface grating implemented on the bottom surface of the waveguide 140.

[0051] Figure 5 illustrates a top view of a waveguide 140 with surface gratings 160 (e.g., gratings on the top surface 146 of the waveguide 140) having different effective pitches according to an embodiment, which different effective pitches can be used in different lasers 112 of the integrated laser array 110. Figure 6 illustrates according to an embodimentFigure 5 Cross-sectional side view of waveguide 140, where perturbation 162 of grating 160 is implemented as a trench. Figure 7 The figure shows according to an embodiment Figure 5 Cross-sectional side view of waveguide 140, where perturbation 162 of grating 160 is implemented as a ridge.

[0052] As Figure 5 shown, the gratings 160 of different lasers 112 may include a plurality of supercells 202, shown as a first supercell 202-11 and a second supercell 202-12. Each supercell 202 may include a first set of elongated perturbations 162 having a first pitch and a second set of elongated perturbations 162 having a second pitch different from the first pitch. For example, for laser 112-1, supercell 202-11 includes 10 perturbations 162 having a first pitch 204 (the first 10 leftmost perturbations as shown for laser 112-1 in Figure 5 ), and the first perturbation of supercell 202-12 is provided at a second pitch 206 from the last perturbation of supercell 202-11 having the first pitch 204. Thus, for supercell 202-11, there are 9 grating periods having the first pitch 204 and 1 grating period having the second pitch 206. For laser 112-2, supercell 202-21 includes 9 perturbations 162 having a first pitch 204 (the first 9 leftmost perturbations as shown for laser 112-2 in Figure 5 ), 1 perturbation having a second pitch 204, and the first perturbation of supercell 202-22 is also provided at a second pitch 206 from the last perturbation of supercell 202-21. Thus, for supercell 202-21, there are 8 grating periods having the first pitch 204 and 2 grating periods having the second pitch 206. For laser 112-3, supercell 202-31 includes 8 perturbations 162 having a first pitch 204 (the first 9 leftmost perturbations as shown for laser 112-2 in Figure 5 ), 2 perturbations having a second pitch 204, and the first perturbation of supercell 202-32 is also provided at a second pitch 206 from the last perturbation of supercell 202-31. Thus, for supercell 202-31, there are 8 grating periods having the first pitch 204 and 2 grating periods having the second pitch 206. Although not specifically shown in this figure, a single grating 160 may include more supercells 202 than just the two supercells 202 shown for each of the lasers 112 in Figures 5 - 7 , for example, hundreds of supercells 202. As with Figures 5 - 7Compared with that shown in [reference], the definition of the supercell 202 can be shifted to the right by one or more perturbations 162. As described above, for each of the lasers 112, this still leaves the same number of grating periods with the first pitch 204 and the second pitch 206, and this still makes the number of perturbations 162 with the first pitch 204 different among the different lasers 112 of the laser array 110, and the number of perturbations 162 with the second pitch 206 different among the different lasers 112 of the laser array 110.

[0053] The effective pitch of the grating can be defined as the average of all pitches of the grating. When the supercells 202 of a given laser 112 are substantially the same, the effective pitch of the grating 160 having multiple supercells 202 is substantially the same as the effective pitch of the supercell 202. For example, consider that the first pitch 204 is 201 nanometers and the second pitch 206 is 202 nanometers. In this case, the effective pitch of the supercell 202 of laser 112-1 is 201.1 nanometers, the effective pitch of the supercell 202 of laser 112-2 is 201.2 nanometers, and the effective pitch of the supercell 203 of laser 112-3 is 201.3 nanometers. In this way, although the first pitch 204 and the second pitch 206 are relatively large, and the resolution of the perturbations 162 of the gratings 160 of all lasers 112 is at least 1 nanometer, the difference in the effective grating pitch from one laser 112 to the next can be less than 1 nanometer (1 angstrom for this example). These values are merely exemplary, and the considerations described herein can be applied to laser arrays having different values of the first pitch 204 and the second pitch 206 and different numbers of perturbations 162 in the set of perturbations of the first pitch 204 and / or the set of perturbations of the second pitch 206. In various embodiments, each of the first pitch 204 and the second pitch 206 can be greater than about 50 nanometers, for example, greater than about 100 nanometers, greater than about 150 nanometers, or greater than about 200 nanometers. In various embodiments, the second pitch 206 can differ from the first pitch 204 by less than about 8 angstroms, for example, less than about 5 angstroms, or about 1 angstrom. In various embodiments, the difference in the center-to-center distance of any two pairs of adjacent (e.g., nearest neighbor) perturbations 162 of the gratings 160 of one laser 112 and another laser 112 can be equal to or greater than about 1 nanometer, which means Figures 5 - 7 all the perturbations 162 of the gratings in the laser array 110 shown in [reference] are fabricated with a resolution of at least 1 nanometer, which is feasible for current manufacturing technologies and facilities.

[0054] Figure 5The top view shows that the perturbation 162 is an elongated perturbation, the major axis of which is perpendicular to the longitudinal axis of the waveguide 140 or extends in a direction perpendicular to the longitudinal axis of the waveguide 140. In other words, the perturbation 162 of the laser array 110 described with reference to Figures 5 - 7 extends in a direction perpendicular to the direction of propagation of the light emitted by the light emitter structure 150.

[0055] Figure 6 The figure shows that in some embodiments, the perturbation 162 can be implemented as a trench. Such a trench can extend from the top surface 146 into the waveguide 140 to a specific depth less than the thickness of the waveguide 140. In some embodiments, the depth of the trench of the perturbation 162 can be less than about 75% of the thickness of the waveguide 140, for example, less than about 50% of the thickness of the waveguide 140, or less than about 25% of the thickness of the waveguide 140.

[0056] Figure 7 The figure shows that in some embodiments, the perturbation 162 can be implemented as a ridge. Such a ridge can extend away from the top surface 146 of the waveguide 140 to a certain height. In some embodiments, the height of the ridge of the perturbation 162 can be at least about 5% of the thickness of the waveguide 140, for example, at least about 15% of the thickness of the waveguide 140, or at least about 25% of the thickness of the waveguide 140.

[0057] Figures 5 - 7 The figure shows that the wavelength λ of different lasers 112 is changed by changing the effective pitch (Δ) of the grating on the waveguide. On the other hand, Figures 8 - 1 0 shows that the wavelength λ of different lasers 112 is changed by changing the width of the waveguide, which changes the effective refractive index (n eff ) of the waveguide.

[0058] Figures 8 - 1 Each of 0 shows the laser array 110 as described above, where the laser array 110 includes three lasers 112. Similarly, the number of lasers 112 is only an example here, and in other embodiments of the laser array 110 as described with reference to Figures 8 - 1 0, the laser array 110 can include only two lasers 112 or more than three lasers 112. Only for Figures 8 - 1 0, the waveguide 140 and the grating 160 are shown for each of the lasers 112 to illustrate how the differences in the grating 160 are implemented for different lasers 112, without obscuring the drawings with details of other components of the lasers 112 (such as the light emitter structure 150 or the backside terminal 142). For each laser 112 and Figures 8 - 1Each of those in 0, a portion of the waveguide 140 with the grating 160 as shown can be a portion of the waveguide 140 with the rear grating 160-1 or a portion of the waveguide 140 with the front grating 160-2 as described with reference to FIGS. 2-4, and can either be implemented adjacent to the optical transmitter structure 150 as described with reference to Figure 2A , Figure 3A and Figure 4A or partially or fully overlap with the optical transmitter structure 150 as described with reference to Figure 2B , Figure 3B and Figure 4B . The grating 160 is described with reference to 0 as a sidewall grating implemented on two sidewalls 148 (i.e., the left sidewall and the right sidewall) of the waveguide 140, but these descriptions equally apply to the grating 160 implemented on only one of the sidewalls 148 of the waveguide 140. Figures 8 - 1 0

[0059] Figure 8 FIG. shows a top view of a waveguide 140 according to an embodiment, the waveguide 140 having sidewall gratings 160 (e.g., gratings on sidewalls 148-1 and 148-2 of the waveguide 140) and different effective widths for different lasers 112 that can be used for the integrated laser array 110, and perturbations 162 of the grating 160 are implemented as trenches. Figure 9 FIG. shows a top view of a waveguide 140 according to an embodiment, the waveguide 140 having sidewall gratings 160 as in Figure 8 and different effective widths, but the perturbations 162 of the grating 160 are implemented as ridges. Figure 10A and Figure 10B show a cross-sectional side view of one of the waveguides 140 according to an embodiment in cross-section of sidewall gratings on two different sidewalls 148. Figure 8 and Figure 9

[0060] As Figure 8 shown, the waveguides 140 of different lasers 112 can include a core portion having a width 302, shown as width 302-1 for laser 112-1, width 302-2 for laser 112-2, and width 302-3 for laser 112-3. Also as Figure 8 shown, the waveguide 140 can also include a sidewall portion having perturbations 162 of the grating 160. In particular, Figure 8 FIG. shows that the perturbation 162 can be a trench implemented in the sidewall 148 of the waveguide 140, where the trench extends from the surface 148 towards the core portion of the waveguide 140. The effective refractive index of the waveguides 140 of different lasers 112 can be changed by changing the width 302 of the core portions of these lasers. As Figure 8As shown, width 302-2 is less than width 302-1, and width 302-3 is less than width 302-2. In Figure 8 the example of Figure 8 , the depth 312 and width 314 of the trench that implements the perturbation 162 can remain substantially the same from one laser 112 to another laser. As a result, as Figure 8 shown in Figure 8 , the effective widths of the different lasers 112 of the laser array 110 are different. As used herein, the term "effective width" of the waveguide 140 refers to the area of the waveguide 140 in a plane parallel to the support (e.g., the area of the occupied space of the top surface 146 of the waveguide 140) divided by the length of the waveguide 140 in that plane (e.g., the length of the occupied space of the top surface of the waveguide). In other words, the "effective width" of the waveguide 140 can be defined as the average value of the widths of the waveguide 140 along the longitudinal axis of the waveguide 140. In some embodiments, the effective width of the waveguide 140 of one of the lasers 112 can differ from the effective width of the waveguide 140 of another one of the lasers 112 by about 1% to about 10% of the effective width of one of these lasers, such as about 1% to about 5%. In some embodiments, in Figure 8 the example of Figure 8 , the depth 312 of the trench that implements the perturbation 162 can be less than about 75% of the effective width of the waveguide 140, such as less than about 50% of the effective width of the waveguide 140, or less than about 25% of the effective width of the waveguide 140.

[0061] When the grating 160 is implemented on one or more sidewalls 148 of the waveguide 140, a change in the effective width of the waveguide 140 changes the relative amount (e.g., changes the weighted average) of the material of the waveguide 140 (e.g., the material in the core portion and between the trenches or in the ridges of the perturbation 162 of the grating 160) and the material of the surrounding medium (e.g., the material filling the trenches or between the ridges of the perturbation 162 of the grating 160). Because the material of the waveguide 140 and the material of the surrounding medium have different refractive indices, a change in the effective width of the waveguide 140 results in a change in the effective refractive index of the waveguide 140, which in turn results in a change in the wavelength supported by the waveguide 140.

[0062] In some embodiments, a change in the effective width of the waveguide 140 from one laser 112 to another in the laser array 110 may result in a change in the grating intensity of the gratings 160 of the different lasers 112, which may be undesirable. Then the change in the grating intensity can be compensated for by adjusting the offset of the perturbation 162 on the opposing sidewalls 148. As Figure 8 shown in Figure 8 , for laser 112-1, the perturbation 162 on sidewall 148-2 is offset from the perturbation 162 on sidewall 148-1 by an offset 304-1. As Figure 8As further shown, for laser 112-2, the perturbation 162 on sidewall 148-2 is offset from the perturbation 162 on sidewall 148-1 by an offset 304-2. Finally, for laser 112-3, the perturbation 162 on sidewall 148-2 is offset from the perturbation 162 on sidewall 148-1 by an offset 304-3. For example, in some embodiments, the offset 304 of the perturbation 162 on the opposing sidewalls 148 of the waveguide 140 of one of the lasers 112 can differ from the offset 304 of the perturbation 162 on the opposing sidewalls 148 of the waveguide 140 of another one of the lasers 112 by the following amount: between about 1% and about 10% of the offset 304 of the perturbation 162 on the opposing sidewall 148 of one of these lasers, such as between about 1% and about 5%. As Figure 8 shown, when the effective width decreases from laser 112-1 to laser 112-3, the offset 304 can increase. Thus, because Figure 8 the effective width of the waveguide 140 of laser 112-2 is less than the effective width of the waveguide 140 of laser 112-1, the offset 304-2 of laser 112-2 is greater than the offset 304-1 of laser 112-1. Similarly, because Figure 8 the effective width of the waveguide 140 of laser 112-2 is less than the effective width of the waveguide 140 of laser 112-2, the offset 304-3 of laser 112-3 is greater than the offset 304-2 of laser 112-2.

[0063] Figure 9 The figure shows a laser array 110 similar to Figure 8 shown, except that the perturbation 162 is implemented as a ridge. Such a ridge can extend away from the corresponding sidewall 148 of the waveguide 140 to a certain height 316 (e.g., the dimension of the perturbation 162 in a direction perpendicular to the corresponding sidewall 148). In some embodiments, the height 316 can be at least about 5% of the average width 302 of the core portion of all the waveguides 140 in the laser array 110, such as at least about 15% or at least about 25%. In some embodiments, the height 316 can be less than about 75% of the effective width of the waveguide 140, such as less than about 50% of the effective width of the waveguide 140, or less than about 25% of the effective width of the waveguide 140.

[0064] Figure 10A and Figure 10B show cross-sectional views of sidewall gratings on two different sidewalls 148 of a cross-section of a waveguide 140 according to an embodiment of Figure 8 and Figure 9 A cross-sectional side view of one of the waveguides 140. In particular, Figure 10A shows a cross-section of the perturbation 162 on sidewall 148-1 Figure 8 andFigure 9 Cross-sectional side view of the waveguide 140 of the laser 112-1, while Figure 10B is shown in a cross-sectional view of the perturbation 162 on the sidewall 148-2 Figure 8 and Figure 9 Cross-sectional side view of the waveguide 140 of the laser 112-1. Figure 10A and Figure 10B The cross-sectional side view shows that the perturbation 162 is an elongated perturbation whose major axis is perpendicular to the longitudinal axis of the waveguide 140 or extends in a direction perpendicular to the longitudinal axis of the waveguide 140. In other words, referring to Figures 8 - 1 the perturbation 162 of the laser array 110 described in 0 extends in a direction perpendicular to the direction of propagation of the light emitted by the light emitter structure 150.

[0065] Although the perturbations 162 on each of the sidewalls 148 shown in Figures 8 - 1 0 have the same period for all the lasers 112, in some embodiments, the embodiments explained with reference to Figures 8 - 1 0 can be combined with the embodiments explained with reference to Figures 5 - 7 as shown, for example, in Figures 4A - 4B .

[0066] An arrangement of two or more lasers 112 having a laser array 110 according to any embodiment disclosed herein can be included in any suitable electronic device. Figures 11 - 13 Illustrates various examples of devices and components that can include the lasers 112 of the laser array 110 according to any embodiment disclosed herein or any combination of such embodiments, or that can include the photonic device 100 having one or more of such laser arrays 110.

[0067] Figure 11 Illustrates a top view of a wafer 2100 and a die 2102 according to an embodiment, which can be included in a photonic device having an integrated laser array, for example, in a photonic device 100 including a laser array 110 and other components (such as modulators and multiplexers) as described herein, or in a photonic device 100 including only the laser array 110 according to any embodiment disclosed herein or any combination of such embodiments. In some embodiments, according to any embodiment disclosed herein, the die 2102 can be included in an IC package. For example, any one of the dies 2102 can be used as Figure 12Any of the dies 2256 in the IC package 2200 shown in [description]. The wafer 2100 may be composed of a semiconductor material and may include one or more dies 2102 having IC structures formed on the surface of the wafer 2100. Each of the dies 2102 may be a repeating unit of a semiconductor product including any suitable IC (e.g., an IC including one or more IC devices implementing a laser array 110 and / or a photon device 100 as described herein). After the manufacture of the semiconductor product is completed (e.g., after manufacturing any embodiment of the laser array 110 and / or the photon device 100 as described herein), the wafer 2100 may undergo a singulation process in which each of the dies 2102 is separated from one another to provide discrete "chips" of the semiconductor product. In particular, a device including one or more laser arrays 110 as described herein and / or a photon device 100 may take the form of the wafer 2100 (e.g., unseparated) or the form of a die 2102 (e.g., separated). The die 2102 may include support circuitry for routing electrical and / or optical signals to various components, e.g., to various lasers 112, transistors, capacitors, resistors, and any other IC components. In some embodiments, the wafer 2100 or the die 2102 may implement or include a laser array (e.g., any embodiment of the laser array 110 having two or more lasers 112 as described herein), a photon device having a laser array (e.g., any embodiment of the photon device 100), or any other suitable circuit element. Multiple of these devices may be combined on a single die 2102. For example, a laser array 110 formed by multiple lasers 112 as described herein may be formed on the same die 2102.

[0068] Figure 12 is a side cross-sectional view of an example microelectronic package 2200 according to any embodiment disclosed herein. The example microelectronic package 2200 may include one or more laser arrays and / or photon devices. In some embodiments, the microelectronic package 2200 may be a system-in-package (SiP).

[0069] The package substrate 2252 may be formed of a dielectric material (e.g., ceramic, laminate film, epoxy film with filler particles therein, etc.) and may have conductive paths 2262 extending through the dielectric material between the faces 2272 and 2274, or between different locations on the face 2272, and / or between different locations on the face 2274.

[0070] The encapsulation substrate 2252 may include conductive contacts 2263 that are coupled through the encapsulation substrate 2252 to a conductive path 2262, thereby allowing circuitry within the die 2256 and / or the interposer 2257 to be electrically coupled to various conductive contacts in the conductive contacts 2264 (or to other devices included in the encapsulation substrate 2252, not shown).

[0071] The microelectronic package 2200 may include an interposer 2257 coupled to the encapsulation substrate 2252 via conductive contacts 2261 of the interposer 2257, first-level interconnects 2265, and conductive contacts 2263 of the encapsulation substrate 2252. Figure 12 The first-level interconnects 2265 illustrated are solder bumps, but any suitable first-level interconnects 2265 may be used. In some embodiments, the microelectronic package 2200 may not include an interposer 2257; instead, the die 2256 may be directly coupled to the conductive contacts 2263 at surface 2272 via the first-level interconnects 2265.

[0072] The microelectronic package 2200 may include one or more dies 2256 coupled to the interposer 2257 via conductive contacts 2254 of the die 2256, first-level interconnects 2258, and conductive contacts 2260 of the interposer 2257. The conductive contacts 2260 may be coupled through the interposer 2257 to a conductive path (not shown), thereby allowing circuitry within the die 2256 to be electrically coupled to respective conductive contacts in the conductive contacts 2261 (or to other devices included in the interposer 2257, not shown). Figure 12 The first-level interconnects 2258 illustrated are solder bumps, but any suitable first-level interconnects 2258 may be used. As used herein, "conductive contact" may refer to a portion of a conductive material (e.g., metal) that serves as an interface between different components; the conductive contact may be recessed from the surface of the component, flush with the surface of the component, or extend away from the surface of the component, and may take any suitable form (e.g., a conductive pad or socket).

[0073] In some embodiments, an underfill material 2266 may be disposed between the encapsulation substrate 2252 and the interposer 2257 around the first-level interconnects 2265, and a molding compound 2268 may be disposed between the die 2256 and the interposer 2257 and in contact with the encapsulation substrate 2252. In some embodiments, the underfill material 2266 may be the same as the molding compound 2268. Example materials useful for the underfill material 2266 and the molding compound 2268 are suitable epoxy molding materials. Second-level interconnects 2270 may be coupled to the conductive contacts 2264. Figure 12The second-level interconnect 2270 illustrated therein is a solder ball (e.g., for a ball grid array arrangement), but any suitable second-level interconnect 2270 (e.g., pins in a pin grid array arrangement or pads in a land grid array arrangement) can be used. The second-level interconnect 2270 can be used to couple the microelectronic package 2200 to another component (such as a circuit board (e.g., a motherboard), an interposer, or another IC package), as is known in the art.

[0074] The die 2256 can take the form of any embodiment of the die 2102 discussed herein (e.g., can include any embodiment of the IC device 110 and / or the photonic device 100 having a laser array as described herein). In embodiments where the microelectronic package 2200 includes multiple dies 2256, the microelectronic package 2200 can be referred to as a multi-chip package (MCP). The die 2256 can include circuitry for performing any desired function. In some embodiments, any one of the dies 2256 can include one or more laser arrays 110 and / or photonic devices 100 as described herein; in some embodiments, at least some of the dies 2256 can not include any laser arrays 110 or photonic devices 100 as described herein.

[0075] Although Figure 12 the microelectronic package 2200 illustrated therein can be a flip-chip package, other packaging architectures can be used. For example, the microelectronic package 2200 can be a ball grid array (BGA) package, such as an embedded wafer-level ball grid array (eWLB) package. In another example, the microelectronic package 2200 can be a wafer-level chip scale package (WLCSP) or a panel fan-out (FO) package. Although Figure 12 two dies 2256 are shown in the microelectronic package 2200 of

[0076] Figure 13is a block diagram of an example photonic device 2300, which may include one or more components, in which a laser array and / or a photonic device as described herein may be implemented. For example, any suitable component among the components of the photonic device 2300 may include a die (e.g., Figure 12 ), having one or more microelectronic packages (e.g., Figure 11 ). More generally, any suitable component among the components of the photonic device 2300 may include one or more of the laser array 110 and / or the photonic device 100 as described herein.

[0077] Multiple components are illustrated as being included in the photonic device 2300 in Figure 13 , but any one or more of these components may be omitted or replicated as appropriate for the application. In some embodiments, some or all of the components included in the photonic device 2300 may be attached to one or more motherboards or any suitable support structure. In some embodiments, some or all of these components are fabricated onto a single system-on-a-chip (SoC) die. Additionally, in various embodiments, the photonic device 2300 may not include Figure 13 one or more of the components illustrated in, but the photonic device 2300 may include interface circuitry for coupling to one or more components. For example, the photonic device 2300 may not include the processing device 2322, but may include processing device interface circuitry (e.g., connectors and driver circuitry) to which the processing device 2322 may be coupled. In another example, the photonic device 2300 may not include the memory 2324, but may include memory interface circuitry (e.g., connectors and support circuitry) to which the memory 2324 may be coupled. In yet another example, the photonic device 2300 may not include the circulator 2318, but may include circulator interface circuitry (e.g., connectors) to which the circulator 2318 may be coupled.

[0078] In some embodiments, the photonic device 2300 may include at least one light source 2302. In some embodiments, the light source 2302 may be or may include the laser array 110 as described herein. Generally, the light source 2302 may include any suitable device for providing the necessary optical signals for various applications of the photonic device 2300, from communication to sensing and imaging. The light source 2302 may be designed to emit light in a controllable and efficient manner to meet the specific requirements of the photonic device 2300. In some embodiments, the light source 2302 may be a coherent and monochromatic light source, such as a laser, for generating light with a well-defined wavelength, low divergence, and high brightness. Examples of lasers that may be included in the light source 2302 include semiconductor lasers, such as edge-emitting lasers and vertical-cavity surface-emitting lasers (VCSELs). Such lasers may be particularly advantageous when the photonic device 2300 is used in applications such as optical communication, sensing, and laser-based therapy in medical devices. In some embodiments, the light source 2302 may be an incoherent light source, such as a light-emitting diode (LED) that emits light when an electric current is applied. LEDs may be simpler and more cost-effective than lasers, making them suitable for applications that do not require high coherence. Using an LED as the light source 2302 may be particularly advantageous when the photonic device 2300 is used in applications such as displays, optical sensors, and short-range communication systems. In further embodiments, the light source 2302 may include one or more of a superluminescent diode (SLD), quantum dots, rare-earth doped fibers / waveguides, plasma sources (e.g., plasmons and microplasma devices), microcavity resonators, or nonlinear optical devices (e.g., photonic devices that use nonlinear optical processes such as frequency doubling or parametric amplification to generate new wavelengths of light).

[0079] In some embodiments, the photonic device 2300 may include at least one optical waveguide component 2304, such as a waveguide, for manipulating and controlling the propagation of light. The optical waveguide component 2304 may include any suitable waveguide structure designed to confine and guide light along a specified path, thereby allowing light to travel from one point to another with minimal loss and dispersion. Examples of waveguides that may be used as the optical waveguide component 2304 include planar waveguides, optical fibers, photonic crystal waveguides, and rib waveguides. In some embodiments, the optical waveguide component 2304 may include a material with a higher refractive index (referred to as the "core") surrounded by a material with a lower refractive index (referred to as the "cladding"). The refractive index contrast between the core and the cladding helps to guide light within the core by using total internal reflection. Due to the reflection of light at the core-cladding interface, the light is trapped within the core. The optical waveguide component 2304 may support various modes of light propagation, such as single-mode or multi-mode.

[0080] In some embodiments, the photonic device 2300 may include at least one PIC 2306. The PIC 2306 may be a miniaturized and integrated optical device that incorporates photonic components such as optical modulators, photodetectors, and waveguides onto a single substrate. In some embodiments, the PIC 2306 may include one or more optical modulators for encoding data onto an optical signal, such as the light generated by the light source 2302. The optical modulators of the PIC 2306 may change certain characteristics of the optical signal, such as its amplitude, frequency, or phase, in order to encode information onto the signal or perform various signal processing functions. Examples of optical modulators that may be implemented in the PIC 2306 include electro-optic modulators, MZI modulators, or microring modulators. In some embodiments, the PIC 2306 may include one or more photodetectors for detecting and measuring the intensity of light or optical radiation across various wavelengths by converting incident light / photons into an electrical signal. Examples of photodetectors that may be implemented in the PIC 2306 include photodiodes, avalanche photodiodes, phototransistors, PIN diodes, CMOS image sensors, photomultiplier tubes, or quantum photodetectors. In some embodiments, the PIC 2306 may include one or more waveguides, for example, any of the waveguides described with reference to the optical waveguide component 2304.

[0081] In some embodiments, the photonic device 2300 may include at least one optical coupling component 2308. The optical coupling component 2308 may include any suitable structure designed to facilitate efficient transmission of light between different optical devices, such as between the light source 2302 and the optical waveguide component 2304, between the light source 2302 and the PIC 2306, between the optical waveguide component 2304 and the PIC 2306, or between the optical waveguide component 2304 or PIC 2306 and a further transmission line (such as an optical fiber ( Figure 13 not shown in the figure)) that may be coupled to the photonic device 2306). Examples of optical coupling elements that may be used to implement the optical coupling component 2308 include fiber optic couplers (e.g., fused fiber optic couplers or tapered fiber optic couplers), waveguide couplers, grating couplers, lens couplers, microlens couplers, prism couplers, fiber array couplers, or ball lens couplers.

[0082] In some embodiments, the photonic device 2300 may include at least one wavelength separator / multiplexer 2310 to combine or separate multiple optical signals carried at different wavelengths. This may be particularly advantageous if the photonic device 2300 is used in an optical communication system such as a WDM system or a DWDM system, in which multiple data channels are simultaneously transmitted on a single optical fiber using light at different wavelengths. In various embodiments, the wavelength separator / multiplexer 2310 may include a wavelength division multiplexer, a wavelength demultiplexer, a passive optical add / drop multiplexer, an arrayed waveguide grating, a fused fiber optic coupler and interleaver, or a filter-based device.

[0083] In some embodiments, the photonic device 2300 may include at least one polarization separator / multiplexer 2312 to combine or separate the multiple optical signals depending on the polarization of the multiple optical signals. Similarly, in some embodiments, the photonic device 2300 may include at least one polarization control component 2314 to control the polarization of the light generated and manipulated in the photonic device 2300. In various embodiments, the polarization separator / multiplexer 2312 and the polarization control component 2314 may include any suitable structure capable of manipulating and managing polarized optical signals, such as birefringent materials, waveguide structures, or dedicated coatings that interact differently with different polarization states.

[0084] In some embodiments, the photonic device 2300 may include at least one general power splitter / multiplexer 2316 to combine or separate multiple optical signals without relying on wavelength or polarization. For example, in some embodiments, the power splitter / multiplexer 2316 may be used to tap a small amount of optical power for power monitoring purposes in the photonic device 2300. Examples of devices that can be used as the power splitter / multiplexer 2316 include directional couplers and multimode interference couplers.

[0085] In some embodiments, the photonic device 2300 may include at least one circulator 2318, also referred to as a "directional separator". The circulator 2318 may include any suitable device configured to guide an optical signal to travel through its ports in a specific one-way circular path. In some embodiments, the circulator 2318 may include a magneto-optic material or other techniques that produce the Faraday rotation effect, in which the polarization of light is rotated as it passes through the circulator 2318.

[0086] In some embodiments, the photonic device 2300 may include at least one mode splitter / multiplexer 2320 to combine or separate multiple optical signals based on the guided modes of the multiple optical signals. Examples of devices that can be used as the mode splitter / multiplexer 2320 include directional couplers, multimode interference couplers, tapered waveguide couplers, photonic lanterns, or photonic crystal splitters.

[0087] In some embodiments, the photonic device 2300 may include a processing device 2322 (e.g., one or more processing devices). As used herein, the term "processing device" or "processor" may refer to any device or portion of a device that processes electronic data from registers and / or memory to transform the electronic data into other electronic data that can be stored in registers and / or memory. The processing device 2322 may include one or more digital signal processors (DSPs), application-specific ICs (ASICs), central processing units (CPUs), graphics processing units (GPUs), cryptographic processors (specialized processors that execute cryptographic algorithms in hardware), server processors, or any other suitable processing device. In some embodiments, the processing device 2322 may include circuitry for controlling the operation of other components of the photonic device 2300 (e.g., for controlling the operation of the PIC 2306).

[0088] In some embodiments, the photonic device 2300 may include a memory 2324, which may itself include one or more memory devices, such as volatile memory (e.g., DRAM), non-volatile memory (e.g., read-only memory (ROM)), flash memory, solid-state memory, and / or hard drives. In some examples, the memory 2404 may include a memory that shares a die with the processing device 2322. The memory may be used as a cache memory and may include embedded DRAM (eDRAM) or spin-transfer torque magnetic random access memory (MRAM). In some embodiments, the processing device 2324 may store instructions or data that the processing device 2322 uses to control the operation of other components of the photonic device 2300 (e.g., to control the operation of the PIC 2306).

[0089] The following paragraphs provide examples of various embodiments disclosed herein.

[0090] Example 1 provides a photonic device that includes: a support (e.g., a die, a wafer, a substrate, or a chip); and one or more lasers disposed above the support, where a single laser among the one or more lasers includes a light emitter structure in a first layer above the support and a waveguide in a second layer above the support, the light emitter structure being configured to emit light. The waveguide is configured to guide the light emitted by the light emitter structure and includes a top surface, a bottom surface opposite the top surface, a first sidewall, and a second sidewall opposite the first sidewall. The waveguide further includes a first elongated perturbation that extends in a direction perpendicular to the longitudinal axis of the waveguide from a first line on a face of the waveguide to the nearest edge (e.g., the top) of the first sidewall (in other words, the first elongated perturbation extends in a direction perpendicular to the propagation direction of the light emitted by the light emitter structure) and further extends from the nearest edge of the first sidewall toward the opposite edge (e.g., the bottom) of the first sidewall, where the face is the top surface or the bottom surface of the waveguide. The waveguide further includes a second elongated perturbation that extends in a direction perpendicular to the longitudinal axis of the waveguide from a second line on a face of the waveguide to the nearest edge (e.g., the top) of the second sidewall (in other words, the second elongated perturbation extends in a direction perpendicular to the propagation direction of the light emitted by the light emitter structure) and further extends from the nearest edge of the second sidewall toward the opposite edge (e.g., the bottom) of the second sidewall, where, in a direction parallel to the longitudinal axis of the waveguide, the second elongated perturbation is offset from the first elongated perturbation by a non-zero distance.

[0091] Example 2 provides a photonic device according to Example 1, wherein one or more lasers include a first laser and a second laser, the first elongated perturbation of the first laser has a first effective pitch, the first elongated perturbation of the second laser has a second effective pitch, and the second effective pitch is different from the first effective pitch.

[0092] Example 3 provides a photonic device according to Example 2, wherein the second effective pitch differs from the first effective pitch by less than about 8 angstroms, for example, less than about 5 angstroms or about 1 angstrom.

[0093] Example 4 provides a photonic device according to Example 2 or 3, wherein each of the first effective pitch and the second effective pitch is greater than about 100 nanometers, for example, greater than about 150 nanometers, or equal to or greater than about 200 nanometers.

[0094] Example 5 provides a photonic device according to any one of Examples 2-4, wherein for the first laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a first effective width; for the second laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a second effective width; and the second effective width is different from the first effective width. As used herein, the term "effective width" of a waveguide refers to the area of the waveguide in a plane parallel to the support (e.g., the area of the occupied space of the top surface of the waveguide) divided by the length of the waveguide in that plane (e.g., the length of the occupied space of the top surface of the waveguide).

[0095] Example 6 provides a photonic device according to Example 5, wherein the second effective width differs from the first effective width by about 1% to about 10% of the first effective width, for example, about 1% to about 5%.

[0096] Example 7 provides a photonic device according to Example 1, wherein one or more lasers include a first laser and a second laser; for the first laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a first effective width; for the second laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a second effective width, and the second effective width is different from the first effective width.

[0097] Example 8 provides a photonic device according to Example 7, wherein the second effective width differs from the first effective width by about 1% to about 10% of the first effective width, for example, about 1% to about 5%.

[0098] Example 9 provides a photonic device according to any of the preceding examples, wherein the first elongated perturbation includes a first plurality of first elongated perturbations and a second plurality of first elongated perturbations, the first plurality of first elongated perturbations having a first pitch (a pitch defined as, for example, a center-to-center distance), the second plurality of first elongated perturbations having a second pitch different from the first pitch, wherein each of the first pitch and the second pitch is greater than about 100 nanometers, such as greater than about 150 nanometers, or equal to or greater than about 200 nanometers.

[0099] Example 10 provides a photonic device according to Example 9, wherein one or more lasers include a first laser and a second laser, and the number of first elongated perturbations in the second plurality of first elongated perturbations of the second laser is different from the number of first elongated perturbations in the second plurality of first elongated perturbations of the first laser.

[0100] Example 11 provides a photonic device according to Example 9 or 10, wherein the effective pitch of the first elongated perturbations is the average of the pitches of all the elongated perturbations of the first elongated perturbations.

[0101] Example 12 provides a photonic device according to any of the preceding examples, wherein the non-zero distance of the offset between the second elongated perturbation and the first elongated perturbation is less than the effective pitch of the first elongated perturbation and less than the effective pitch of the second elongated perturbation.

[0102] Example 13 provides a photonic device according to any of the preceding examples, wherein the first line and the second line are substantially parallel to the longitudinal axis of the waveguide and are at a non-zero distance from each other.

[0103] Example 14 provides a photonic device according to Example 13, wherein the non-zero distance between the first line and the second line is less than about 50% of the effective width of the waveguide.

[0104] Example 15 provides a photonic device according to any of Examples 1-14, wherein the first elongated perturbation and / or the second elongated perturbation is a trench.

[0105] Example 16 provides a photonic device according to any of Examples 1-14, wherein the first elongated perturbation and / or the second elongated perturbation is a ridge.

[0106] Example 17 provides a photonic device according to any of the preceding examples, wherein the light emitter structure includes a III-V semiconductor material and / or wherein the waveguide includes silicon.

[0107] Example 18 provides a photonic device according to any of Examples 1-17, wherein the second layer is closer to the support than the first layer.

[0108] Example 19 provides a photonic device according to any one of Examples 1-17, wherein the second layer is closer to the support than the first layer.

[0109] Example 20 provides a photonic device according to any one of Examples 1-17, wherein, for a single laser, the footprint of the optical emitter structure overlaps with the footprint of the first elongated perturbation and / or the footprint of the optical emitter structure further overlaps with the footprint of the second elongated perturbation, or the footprint of the optical emitter structure is adjacent to the footprint of the first elongated perturbation in a direction parallel to the longitudinal axis of the waveguide.

[0110] Example 21 provides a photonic device including a laser array, the laser array including: a first laser and a second laser, wherein: each of the first laser and the second laser includes an optical emitter structure, the optical emitter structure includes a III-V semiconductor material, and further includes a waveguide having a grating, the grating including silicon; the effective pitch of the grating of the second laser differs from the effective pitch of the grating of the first laser by less than about 1 nanometer, such as less than about 5 angstroms; and the difference in the center-to-center distance of any two pairs of adjacent (e.g., nearest neighbor) elongated perturbations of the grating of the first laser and the grating of the second laser is at least 1 nanometer.

[0111] Example 22 provides a photonic device according to Example 21, wherein the effective pitch of the grating of the second laser differs from the effective pitch of the grating of the first laser by about 1 angstrom.

[0112] Example 23 provides a photonic device according to Example 21 or 22, wherein the grating includes a first plurality of elongated perturbations and a second plurality of elongated perturbations, the first plurality of elongated perturbations having a first pitch (defined as, for example, the pitch of the center-to-center distance), the second plurality of elongated perturbations having a second pitch different from the first pitch, wherein each of the first pitch and the second pitch is greater than about 100 nanometers, such as greater than about 150 nanometers, or equal to or greater than about 200 nanometers.

[0113] Example 24 provides a photonic device according to Example 23, wherein the number of elongated perturbations in the second plurality of elongated perturbations of the second laser is different from the number of elongated perturbations in the second plurality of elongated perturbations of the first laser.

[0114] Example 25 provides a photonic device according to Example 23 or 24, wherein the effective pitch of the grating is the average of the pitches of all the elongated perturbations of the grating.

[0115] Example 26 provides a photonic device according to any one of Examples 21-25, wherein the waveguide is above the optical emitter structure.

[0116] Example 27 provides a photonic device according to Example 26, further comprising a support (e.g., a substrate, die, or wafer), wherein the light emitter structure is between the support and the waveguide.

[0117] Example 28 provides a photonic device according to any one of Examples 21-52, wherein the waveguide is below the light emitter structure.

[0118] Example 29 provides a photonic device according to Example 28, further comprising a support (e.g., a substrate, die, or wafer), wherein the waveguide is between the support and the light emitter structure.

[0119] Example 30 provides a photonic device according to Example 27 or 29, wherein the support is a substrate comprising silicon.

[0120] Example 31 provides a photonic device according to any one of Examples 26-30, wherein the footprint of the grating overlaps the footprint of the light emitter structure.

[0121] Example 32 provides a photonic device according to any one of Examples 21-25, wherein the grating is adjacent to the light emitter structure along the longitudinal axis of the light emitter structure.

[0122] Example 33 provides a photonic device according to any one of Examples 21-32, wherein the longitudinal axis of the grating is parallel to the longitudinal axis of the light emitter structure.

[0123] Example 34 provides a photonic device according to any one of Examples 21-33, wherein the effective width of the waveguide of the second laser is different from the effective width of the waveguide of the first laser.

[0124] Example 35 provides a photonic device according to Example 34, wherein the difference between the effective width of the waveguide of the second laser and the effective width of the waveguide of the first laser is between about 1% and about 10% of the effective width of the waveguide of the first laser, such as between about 1% and about 5%.

[0125] Example 36 provides a photonic device according to any one of Examples 34 or 35, wherein the waveguide comprises a first sidewall, a second sidewall opposite the surface of the first sidewall, a plurality of elongated perturbations at the first sidewall, and a plurality of elongated perturbations at the second sidewall, wherein the plurality of elongated perturbations at the second sidewall are offset from the plurality of elongated perturbations at the first sidewall.

[0126] Example 37 provides a photonic device according to Example 36, wherein the offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the second laser is different from the offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the first laser.

[0127] Example 38 provides a photonic device according to Example 37, wherein the amount by which the offset between the plurality of elongated perturbations at the first sidewall of the waveguide of the second laser differs from the offset between the plurality of elongated perturbations at the first sidewall of the waveguide of the first laser and the plurality of elongated perturbations at the second sidewall is: between about 1% and about 10% of the offset between the plurality of elongated perturbations at the first sidewall of the waveguide of the first laser and the plurality of elongated perturbations at the second sidewall, such as between about 1% and about 5%.

[0128] Example 39 provides a photonic device according to any one of Examples 36 - 38, wherein the height of the plurality of elongated perturbations at the first sidewall or the height of the plurality of elongated perturbations at the second sidewall is less than about 75% of the effective width of the waveguide. In this context, the height of the elongated perturbation refers to the dimension of the elongated perturbation in a direction perpendicular to the corresponding sidewall.

[0129] Example 40 provides a photonic device according to any one of Examples 34 - 39, wherein the effective width of the waveguide is the average of the widths of the waveguide along the longitudinal axis of the waveguide.

[0130] Example 41 provides a photonic device according to any one of Examples 21 - 40, wherein the grating includes elongated grooves in one or more surfaces of the waveguide, and the elongated grooves extend in a direction perpendicular to the longitudinal axis of the waveguide (in other words, the grooves extend in a direction perpendicular to the propagation direction of the light emitted by the light emitter structure).

[0131] Example 42 provides a photonic device according to any one of Examples 21 - 40, wherein the grating includes elongated ridges in one or more surfaces of the waveguide, and the elongated ridges extend in a direction perpendicular to the longitudinal axis of the waveguide (in other words, the ridges extend in a direction perpendicular to the propagation direction of the light emitted by the light emitter structure).

[0132] Example 43 provides a photonic device that includes a laser array, the laser array including a first laser and a second laser, wherein each of the first laser and the second laser includes a light emitter structure that includes III - V semiconductor material, and further includes a waveguide having a sidewall grating, the waveguide and the grating including silicon, and wherein the effective width of the waveguide of the second laser is different from the effective width of the waveguide of the first laser.

[0133] Example 44 provides a photonic device according to Example 43, wherein the effective width of the waveguide of the second laser differs from the effective width of the waveguide of the first laser by between about 1% and about 10% of the effective width of the waveguide of the first laser, such as between about 1% and about 5%.

[0134] Example 45 provides a photonic device according to any one of Examples 43 or 44, wherein the waveguide includes a first sidewall, a second sidewall opposite the first sidewall, a plurality of elongated perturbations at the first sidewall, and a plurality of elongated perturbations at the second sidewall, wherein the plurality of elongated perturbations at the second sidewall are offset from the plurality of elongated perturbations at the first sidewall.

[0135] Example 46 provides a photonic device according to Example 45, wherein the offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the second laser is different from the offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the first laser.

[0136] Example 47 provides a photonic device according to Example 46, wherein the amount by which the offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the second laser differs from the offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the first laser is between about 1% and about 10%, for example between about 1% and about 5%, of the offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the first laser.

[0137] Example 48 provides a photonic device according to any one of Examples 45-47, wherein the height of the plurality of elongated perturbations at the first sidewall or the height of the plurality of elongated perturbations at the second sidewall is less than about 75% of the effective width of the waveguide. In this context, the height of the elongated perturbation refers to the dimension of the elongated perturbation in a direction perpendicular to the corresponding sidewall.

[0138] Example 49 provides a photonic device according to any one of Examples 45-48, wherein the elongated perturbation at the first sidewall is an elongated groove extending in a direction perpendicular to the longitudinal axis of the waveguide (in other words, the groove extends in a direction perpendicular to the direction of propagation of the light emitted by the light emitter structure).

[0139] Example 50 provides a photonic device according to any one of Examples 45-48, wherein the elongated perturbation at the first sidewall is an elongated ridge extending in a direction perpendicular to the longitudinal axis of the waveguide (in other words, the ridge extends in a direction perpendicular to the direction of propagation of the light emitted by the light emitter structure).

[0140] Example 51 provides a photonic device according to any of the foregoing examples, wherein the photonic device includes a laser array, the laser array includes N lasers, N is an integer greater than 1, one or more lasers according to any of Examples 1-20, or a first laser and a second laser according to any of Examples 21-50 are lasers among the N lasers, and different lasers among the N lasers are configured to output light with different central wavelengths.

[0141] Example 52 provides a photonic device according to Example 51, wherein the wavelength interval between different lasers of the laser array is equivalent to a frequency interval of about 100 GHz.

[0142] Example 53 provides a photonic device according to Example 51 or 52, wherein the optical emitter structures of different lasers are configured to emit light with approximately the same wavelength.

[0143] Example 54 provides a photonic device according to any of Examples 51-53, further including a wavelength synthesizer configured to combine the light output by the N lasers into a single optical signal.

[0144] Example 55 provides a photonic device according to Example 54, further including a separator configured to separate the single optical signal into M optical signals, where M is an integer greater than 1, and where M may be equal to but not necessarily equal to N.

[0145] Example 56 provides a photonic device according to Example 55, wherein each of the M optical signals is a signal including different central wavelengths of the N lasers.

[0146] Example 57 provides a photonic device according to Example 56, further including a corresponding plurality of modulators in the path of each of the M optical signals.

[0147] Example 58 provides a photonic device according to Example 57, wherein the modulator is a ring modulator.

[0148] Example 59 provides a photonic device according to Example 57 or 58, wherein the modulator is a silicon modulator.

[0149] Example 60 provides a photonic device according to any of Examples 55-59, further including an N×M multiplexer, where the N×M multiplexer includes a wavelength synthesizer and a separator.

[0150] Example 61 provides a photonic device according to any of Examples 51-60, further including corresponding backside terminals for each of the N lasers.

[0151] Example 62 provides a photonic device according to any one of Examples 51-61, wherein the light output by each of the N lasers is an optical signal including a single central wavelength.

[0152] Example 63 provides a photonic device according to any one of the foregoing examples, further comprising at least one of a circulator, a photodetector, a wavelength separator, a polarization separator, or a mode separator.

[0153] Example 64 provides a microelectronic component comprising: a die; and further components coupled to the die, wherein the die comprises a photonic device according to any one of the foregoing examples.

[0154] Example 65 provides the microelectronic component according to Example 64, wherein the further component is one of a package substrate, a circuit board, an interposer, or another die.

[0155] Example 66 provides the microelectronic component according to Example 64 or 65, further comprising one or more interconnects for coupling the further components to the die.

[0156] The foregoing description of the illustrated implementations of the present disclosure (including what is described in the abstract) is not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed. Although specific embodiments and examples of the present disclosure have been described herein for purposes of illustration, various equivalent modifications are possible within the scope of the present disclosure, as will be appreciated by those skilled in the relevant art. These modifications may be made in view of the above detailed description.

Claims

1. A photonic device, comprising: Supports; as well as one or more lasers above the support, a single laser of the one or more lasers comprising a light emitter structure in a first layer above the support, and a waveguide in a second layer above the support, the waveguide comprising: a top surface, a bottom surface opposite to the top surface, a first side wall, and a second side wall opposite to the first side wall, a first elongated perturbation extending in a direction perpendicular to the longitudinal axis of the waveguide from a first line on a face of the waveguide to a nearest edge of the first sidewall and further extending from the nearest edge of the first sidewall towards an opposite edge of the first sidewall, wherein the face is the top face or the bottom face of the waveguide, and a second elongated perturbation extending in the direction perpendicular to the longitudinal axis of the waveguide from a second line on the face of the waveguide to a nearest edge of the second sidewall and further extending from the nearest edge of the second sidewall towards an opposite edge of the second sidewall, Wherein, in a direction parallel to the longitudinal axis of the waveguide, the second elongated perturbation is offset from the first elongated perturbation by a non-zero distance.

2. The photonic device according to claim 1, characterized in that: The one or more lasers include a first laser and a second laser, The first elongated perturbations of the first laser have a first effective pitch, The first elongated perturbations of the second laser have a second effective pitch, and The second effective pitch is different from the first effective pitch.

3. The photonic device according to claim 2, characterized in that: The second effective pitch differs from the first effective pitch by less than about 5 angstroms.

4. The photonic device according to claim 2, characterized in that: Each of the first effective pitch and the second effective pitch is greater than about 100 nanometers.

5. The photonic device according to claim 2, characterized in that: For the first laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a first effective width, For the second laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a second effective width, and The second effective width is different from the first effective width.

6. The photonic device according to claim 5, characterized in that The second effective width differs from the first effective width by about 1% to about 10% of the first effective width.

7. The photonic device according to claim 1, characterized in that: The one or more lasers include a first laser and a second laser, For the first laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a first effective width, For the second laser, the portion of the waveguide including the first elongated perturbation and the second elongated perturbation has a second effective width, and The second effective width is different from the first effective width.

8. The photonic device according to any one of claims 1 to 7, characterized in that: The first elongated disturbance comprises: a first plurality of said first elongated perturbations, said first plurality of said first elongated perturbations having a first pitch, and a second plurality of said first elongated perturbations, said second plurality of said first elongated perturbations having a second pitch different from said first pitch, Wherein each of the first pitch and the second pitch is greater than about 100 nanometers.

9. The photonic device according to claim 8, characterized in that: The one or more lasers include a first laser and a second laser, and The number of the first elongated perturbations in the second plurality of the first elongated perturbations of the second laser is different from the number of the first elongated perturbations in the second plurality of the first elongated perturbations of the first laser.

10. The photonic device according to any one of claims 1 to 7, characterized in that: The non-zero distance of the offset between the second elongate perturbation and the first elongate perturbation is less than an effective pitch of the first elongate perturbation.

11. The photonic device according to any one of claims 1 to 7, characterized in that: The first line and the second line are substantially parallel to the longitudinal axis of the waveguide and are located at a non-zero distance from each other.

12. The photonic device according to claim 11, characterized in that The non-zero distance between the first line and the second line is less than about 50% of an effective width of the waveguide.

13. The photonic device according to any one of claims 1 to 7, characterized in that: The first elongate perturbation is a groove or a ridge.

14. The photonic device according to any one of claims 1 to 7, characterized in that: For the single laser, the footprint of the light emitter structure overlaps with the footprint of the first elongated perturbation and further overlaps with the footprint of the second elongated perturbation.

15. The photonic device according to claim 1, characterized in that: For the single laser, the footprint of the light emitter structure is adjacent to the footprint of the first elongated perturbation in the direction parallel to the longitudinal axis of the waveguide.

16. A photonic device, comprising: First laser; as well as The second laser wherein a single one of the first laser and the second laser comprises a waveguide having a grating, the effective pitch of the grating of the second laser differs from the effective pitch of the grating of the first laser by less than about 5 angstroms, and the difference in center-to-center distances of any two pairs of adjacent elongated perturbations of the grating of the first laser and the grating of the second laser is at least 1 nanometer.

17. The photonic device according to claim 16, characterized in that The grating comprises: a first plurality of elongated perturbations having a first pitch, and a second plurality of elongated perturbations having a second pitch different from the first pitch, Wherein each of the first pitch and the second pitch is greater than about 100 nanometers.

18. A photonic device comprising: First laser; as well as The second laser wherein a single laser of the first laser and the second laser comprises a waveguide comprising a first sidewall, a second sidewall opposite the first sidewall, a plurality of elongated perturbations at the first sidewall, and a plurality of elongated perturbations at the second sidewall, wherein the plurality of elongated perturbations at the second sidewall are offset from the plurality of elongated perturbations at the first sidewall, and wherein an offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the second laser is different from an offset between the plurality of elongated perturbations at the first sidewall and the plurality of elongated perturbations at the second sidewall of the waveguide of the first laser.

19. The photonic device according to claim 18, characterized in that The effective width of the waveguide of the second laser differs from the effective width of the waveguide of the first laser by about 1% to about 10% of the effective width of the waveguide of the first laser.

20. The photonic device of claim 18 or 19, further comprising: a wavelength synthesizer configured to combine light output by the first laser and the second laser into a single optical signal; a splitter configured to split the single optical signal into M optical signals, wherein M is an integer greater than 1, and wherein each of the M optical signals is a signal including a different wavelength of the first laser and the second laser; as well as A series of ring modulators in the path of each of the M optical signals.

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