Optical waveguide amplifier with doped silicon-based core

Abstract

An optical waveguide amplifier with a doped silicon-based core is disclosed. An optical device includes a praseodymium (Pr) doped waveguide optical amplifier capable of amplifying O-band light. The waveguide optical amplifier may be formed on a substrate (e.g., silicone or glass) and include a core defining an optical path through the waveguide optical amplifier and a cladding adjacent at least one side of the core. The core comprises a silicon-based material doped with praseodymium (Pr), such as silicon nitride (Si3N4), such that the waveguide optical amplifier amplifies the O-band signal light under conditions where pump light and O-band signal light pass through the waveguide optical amplifier.

Description

[0001] introduction

[0002] In photonic communications, information is encoded in optical signals and transmitted through photonic interconnects (such as optical fibers). When light is transmitted through such interconnects, the intensity of the optical signal tends to weaken due to dispersion, leakage, or other effects. Therefore, in order to avoid the signal becoming too weak, optical amplifiers are usually added periodically in the photonic network to amplify the optical signal. Optical amplifiers are usually configured to amplify optical signals whose wavelengths fall within a specific range (band), and are generally not used to amplify optical signals whose wavelengths are outside this range. Therefore, different types of optical amplifiers can be used in different networks, depending on which specific wavelengths of light are used in this network. For example, long-distance communication networks (such as telecommunications interconnects) traditionally utilize light in the so-called C-band (wavelengths of 1530-1565nm), and therefore optical amplifiers configured to operate in the C-band are often desired for such applications. On the other hand, data centers or other more localized interconnects tend to use light in the so-called O-band (wavelengths of 1260-1360nm), and therefore optical amplifiers configured to operate in the O-band are often desired for such applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Alone or with Figure 1 The present disclosure can be understood from the following detailed description. These drawings are included to provide a further understanding of the present disclosure, and are incorporated into and constitute a part of this specification. The drawings illustrate one or more examples of the present teachings and together with the description explain certain principles and operations. In the drawings:

[0004] Figure 1 is a schematic cross-section of an example optical device including a waveguide optical amplifier, wherein the cross-section is taken along Figure 2 The 1-1 interception.

[0005] Figure 2 yes Figure 1 Schematic plan view of an example optical device.

[0006] Figure 3 is a block diagram illustrating an example optical circuit including example optics and forward pumping components.

[0007] Figure 4 is a block diagram illustrating another example optical circuit including an example optical device having a forward pumping component and a reverse pumping component.

[0008] Figure 5 is a schematic plan view of another example optical device including a waveguide optical amplifier having juxtaposed input and output ports.

[0009] Figure 6 is a block diagram illustrating another example optical circuit including an optical device and a discrete polarization beam splitter and combiner.

[0010] Figure 7 is a schematic plan view of another example optical device including a waveguide optical amplifier with an integrated polarization beam splitter and beam combiner.

[0011] Figure 8 is a schematic plan view of another example optical device including a multiple waveguide optical amplifier with interleaved waveguides.

[0012] Fig. 9 is a schematic plan view of another example optical device including a multiple waveguide optical amplifier having interleaved waveguides and juxtaposed input and output ends.

[0013] Fig.10 is a schematic plan view of another example optical device including a multiple waveguide optical amplifier having interleaved waveguides and juxtaposed input and output ends.

[0014] Fig.11 is a schematic plan view of another example optical device including a waveguide optical amplifier having a serpentine waveguide.

[0015] Fig.12 is a schematic cross-section of another example optical device including a waveguide optical amplifier comprising a doped core portion and an undoped core portion located in the same vertical layer.

[0016] Fig.13 is a schematic cross-section of another example optical device including a waveguide optical amplifier comprising a doped core portion and an undoped core portion located in different vertical layers.

[0017] Fig.14 is a schematic plan view of another example optical device including a waveguide optical amplifier with an integrated wavelength division (WDM) combiner and doped core sections and undoped core sections located in the same vertical layer.

[0018] Fig.15 is a schematic plan view of another example optical device including a waveguide optical amplifier with an integrated WDM combiner and doped core sections and undoped core sections located in the same vertical layer.

[0019] Fig.16 is a schematic plan view of another example optical device including a waveguide optical amplifier with an integrated WDM combiner and doped core sections and undoped core sections located in the same vertical layer.

[0020] Fig.17is a schematic plan view of another example optical device including a waveguide optical amplifier with an integrated WDM combiner and doped core sections and undoped core sections located in the same vertical layer.

[0021] Fig.18 is a schematic plan view of another example optical device including an array of multiple waveguide optical amplifiers with integrated WDM combiners located in the same vertical layer.

[0022] Fig.19 is a schematic plan view of another example optical device including a multiple waveguide optical amplifier with interleaved waveguides in the same vertical layer and an integrated WDM combiner.

[0023] Fig. 20 is a schematic plan view of another example optical device including a waveguide optical amplifier with an integrated polarization beam splitter and combiner and an integrated WDM beam combiner located in the same vertical layer.

[0024] Fig.21 is a schematic plan view of another example optical device including a waveguide optical amplifier with integrated WDM combiners located in different vertical layers.

[0025] Fig. 22 is a schematic plan view of another example optical device including a waveguide optical amplifier having an integrated polarization beam splitter and combiner located in different vertical layers and an integrated WDM combiner.

[0026] Fig.23 is a schematic cross-section of another example optical device including a waveguide optical amplifier comprising two doped core sections located in different vertical layers.

[0027] Fig.24 is a schematic plan view of an example optical device including a waveguide optical amplifier comprising two doped waveguide core sections formed in different vertical layers.

[0028] Fig.25 yes Fig.24 Schematic plan view of one layer of an example optical device.

[0029] Fig.26 yes Fig.24 Schematic plan view of another layer of an example optical device.

[0030] Fig. 27 is a schematic plan view of an example optical device including two waveguide optical amplifiers formed in different vertical layers.

[0031] Fig.28 yes Fig. 27Schematic plan view of one layer of an example optical device.

[0032] Fig.29 yes Fig. 27 Schematic plan view of another layer of an example optical device.

[0033] Fig.30 is a schematic cross-section of another example optical device including a waveguide optical amplifier comprising a doped core portion and an undoped core portion located in the same vertical layer.

[0034] Fig.31 is a schematic cross-section of another example optical device including a waveguide optical amplifier comprising a doped core portion and an undoped core portion located in different vertical layers. DETAILED DESCRIPTION

[0035] Various waveguide optical amplifiers and optical devices including such optical amplifiers are disclosed herein. The waveguide optical amplifier disclosed herein includes a waveguide formed on a silicon substrate. More specifically, each of the disclosed waveguides has a core portion defining an optical path and a cladding at least partially surrounding the core portion, wherein the core portion is formed of a silicon-based material such as silicon nitride (Si3N4) that has been doped with rare earth elements, and the cladding includes a silicon-based material such as silicon oxide (SiO2) having a different refractive index. The core and the cladding together form a waveguide that guides light along the optical path defined by the core. In addition, when an optical signal is transmitted through this waveguide, it interacts with the dopant atoms in the core and is amplified via stimulated emission. Specifically, a process also known as "pumping" is used to excite the dopant, which includes passing light of a specific wavelength ("pump light") through the waveguide, wherein the pump light is absorbed by the dopant atoms, and thereby the electrons of the dopant atoms are excited from a ground energy state to an excited energy state. Then, the light signal carrying the information to be amplified is passed through the waveguide, and when this signal light encounters the excited dopant atoms, this signal light will interact with the excited electrons of the dopant atoms and cause the electrons to transition to a lower energy state and also release photons (light). The released photons have the same wavelength as the original signal light and travel in the same direction as the original signal light, and thus the released photons join with the signal light, thereby increasing the overall intensity of the signal. Many such stimulated emissions occur as the signal light passes through the waveguide, resulting in the intensity of the signal light leaving the waveguide being greatly amplified compared to the signal light entering the waveguide.

[0036] In some examples, the dopant used in the core portion of the waveguide includes praseodymium (Pr), and the waveguide optical amplifier is capable of operating in the O-band. This may be referred to as a Pr-doped waveguide amplifier (PDWA). Such a PDWA may be relatively small, cost-effective, and low-noise compared to other types of optical amplifiers, as will be discussed further below.

[0037] In some examples, the optical devices disclosed herein include a combination of doped waveguide portions and undoped waveguide portions disposed in the same chip. More specifically, these example optical devices have at least a first waveguide core portion and a second waveguide core portion, the first waveguide core portion comprising doped Si3N4 (doped with rare earth elements such as praseodymium (Pr), erbium (Er), ytterbium (Yb), etc.), and the second waveguide core portion comprising undoped Si3N4. The doped waveguide core portion forms a waveguide optical amplifier (such as one of the above-mentioned PDWAs), while the undoped waveguide core portion can form a waveguide for another optical component (such as a wavelength division (WDM) coupler). The waveguide optical amplifier and other optical components formed by doped and undoped waveguide core portions are integrated on the same chip. In other words, the optical device is a photonic integrated circuit including a waveguide optical amplifier (having a doped waveguide core portion) and another optical component (having an undoped waveguide core portion). In some examples, the doped and undoped waveguide core portions are arranged in a unified vertical layer of the chip (vertical here refers to the direction of layer stacking). In other examples, the doped and undoped waveguide core portions are arranged in different vertical layers of the chip, and in some cases can vertically overlap each other.

[0038] In some examples, optical devices disclosed herein include multiple doped waveguide core sections formed in different vertical layers. For example, some optical devices disclosed herein may include two separate waveguide optical amplifiers formed in different vertical layers on the same chip. As another example, some optical devices disclosed herein may include a single waveguide optical amplifier having multiple doped waveguide sections formed in different vertical layers on the same chip.

[0039] In some examples, the optical amplifier disclosed herein has a waveguide defining a double helix path, which is relatively space-efficient, allowing a long waveguide to be formed in a relatively small area. In some examples, by arranging the waveguides as parallel staggered double helices, multiple such waveguides can be placed in substantially the same area of ​​the chip, allowing further space efficiency to be achieved.

[0040] In addition, some of the example optical amplifiers disclosed herein are modular in that they can be used as building blocks that can be combined together to generate larger optical systems that include multiple optical amplifiers. For example, optical amplifiers can be arranged in one-dimensional, two-dimensional, or three-dimensional arrays of any size to form a system capable of amplifying any number of input optical signals. Optical amplifiers can be arranged in parallel to amplify multiple optical channels and can be arranged in series to amplify a single optical channel. These arrays can include discrete chips arranged together, or can be formed together as part of the same chip (i.e., forming a photonic integrated circuit).

[0041] In addition, various different configurations for various waveguide optical amplifiers are disclosed herein, including configurations having various layouts for input ports and output ports. For example, in some waveguide optical amplifiers disclosed herein, the input ports and output ports are arranged on different edges of the device, while in other examples, the input ports and output ports are arranged on the same edge of the device.

[0042] In addition, some example optical devices disclosed herein implement polarization diversity schemes that allow waveguide amplifiers to successfully amplify optical signals with two polarizations. For example, in some optical devices disclosed herein, polarization beam splitters, rotators, and combiners can be integrated into the same chip as waveguide optical amplifiers.

[0043] As described above, in some cases, the various waveguide optical amplifiers and associated optical devices disclosed herein may have some advantages over other types of optical amplifiers. One type of optical amplifier is a fiber amplifier (FOA), which includes a certain length of optical fiber doped with rare earth elements. There are different FOAs for different bands of the photonic communication spectrum, including C-band, O-band and other bands. However, in such FOAs, a longer length of doped optical fiber is usually required to obtain the desired amplification, and because the optical fiber cannot usually be bent very tightly, the FOA usually has a relatively large fiber ring. Therefore, the FOA tends to be quite large and bulky, and may not be well suited for use in data centers or other applications where space may be more limited. In contrast, the optical devices and waveguide optical amplifiers disclosed herein can be made relatively small, and therefore may be better suited for such applications.

[0044] Another type of optical amplifier is a semiconductor optical amplifier (SOA) formed using III-V semiconductor media. These SOAs use quantum dots, quantum wells, or bulk semiconductors and hole / electron recombination phenomena to amplify optical signals. Such SOAs can be very small. However, SOAs also tend to have high noise and some other disadvantages, and therefore they may not be suitable for all applications. In contrast, the optical devices and waveguide optical amplifiers disclosed in this article are also relatively small, but have much less noise.

[0045] Another type of optical amplifier is an erbium (Er) doped waveguide formed on a silicon substrate (i.e., an Er doped waveguide amplifier (EDWA)). These can be relatively small and cost-effective with relatively low noise. However, these EDWAs typically operate only in the C-band and therefore may not be suitable for applications using O-band light (such as data centers). In contrast, the PDWA disclosed herein is capable of operating in the O-band. In addition, the example waveguide optical amplifier disclosed herein may include a relatively more space-saving waveguide design, allowing a smaller package than some EDWAs. In addition, the example waveguide optical amplifier disclosed herein may include vertically stacked waveguide components, allowing a higher spatial efficiency than some EDWAs. In addition, the example waveguide optical amplifier disclosed herein may include an undoped waveguide component integrated with the waveguide optical amplifier, thereby avoiding the need to provide a separate optical component, increasing convenience and usability, and further optimizing spatial efficiency compared to some EDWAs.

[0046] Turning now to the drawings, various devices, systems, and methods according to aspects of the present disclosure will be described.

[0047] Figure 1 and Figure 2 An example optical device 10 including a Pr-doped waveguide optical amplifier (PDWA) 20 capable of amplifying light having a wavelength in the O-band ("O-band light") is schematically illustrated. Figure 2 The optical device 10 is shown in plan view, and Figure 1 shows that there is Figure 2 1 - 1 is a cross section of a portion of the optical device 10 . Figure 1 and Figure 2 It is schematic in nature and, unless otherwise noted, is not intended to be accurate or to scale with respect to specific dimensions or other structural details.

[0048] The optical device 10 includes a substrate 15 and a PDWA 20 formed on the substrate 15. In an example, the substrate 15 includes silicon (Si). In another example, the substrate may be glass. The substrate 15 may have various sizes, which may include various industry standard sizes. In an example, the thickness of the substrate 15 may be about 0.5 mm to 1.5 mm.

[0049] The PDWA 20 includes a waveguide formed by a waveguide cladding 30 and a waveguide core 40, wherein the cladding 30 at least partially surrounds the core in a cross section of the core 40 (i.e., the cladding 30 abuts at least one side of the core 40, and in some cases abuts multiple sides thereof). The core 40 is doped with Pr atoms, which allows amplification of O-band light, as will be described in more detail below. Both the cladding 30 and the core 40 are formed of silicon-based materials (having different refractive indices). In an example, the cladding 30 includes silicon dioxide (SiO2) and the core includes Pr-doped silicon nitride (Si3N4). Other silicon-based materials may also be used for either or both of the core 40 and / or the cladding 30. For example, a silicon-rich nitride, silicon oxynitride (Si(x)O(y)N(z)) may be used for both the core 40 and the cladding 30, wherein the composition of the silicon oxynitride is adjusted to achieve a high or low refractive index for use as the core 40 and the cladding 30, respectively. As another example, SiO 2 may be used for the core 40 , or Si 3 N 4 may be used for the cladding 30 .

[0050] The thickness of cladding 30 is a design parameter and depends on the intended device and the refractive indices of core 40 and cladding 30 (in other words, the exact material composition of each layer). In some examples, cladding 30 may be approximately 0.05 microns to 5 microns thick.

[0051] In some examples, the core 40 may also be doped with other rare earth elements in addition to Pr. The Pr dopant may continue to act as the main optical amplifier providing the desired amplification of O-band light, but additional rare earth dopants may be co-implanted with the Pr dopant to act as a sensitizer and increase the pumping efficiency of the Pr atoms, or to achieve some other desired effect. One example of a suitable material for co-implantation with the Pr dopant is ytterbium (Yb).

[0052] exist Figure 1 In the embodiment, the waveguide of the PDWA 20 has a buried channel configuration, wherein the cladding 30 surrounds the core 40 at the top, bottom, and both sides. Specifically, in some examples, the width of the core 40 is about 600 nm (in Figure 1 ) and the height is about 300 nm (indicated by w in Figure 1 This configuration, together with the materials mentioned for the core 40 and channel 30, can allow the waveguide to have a moderate Δn of about 0.17, relatively low losses, high optical confinement, good field overlap between pump and signal modes, and a low minimum bending radius. In some examples, the waveguide is single mode for pumping and spans the entire O-band. Although Figure 1 and Figure 2 Not shown in the figure, but an adiabatic transition can be used to transition to a wider multimode waveguide to obtain lower propagation losses without exciting higher order modes in the wider waveguide.

[0053] In other examples, the waveguide of the PDWA 20 can have other configurations, such as: a ridge configuration, in which the cladding 30 abuts the bottom side of the core 40, while the other side is open to air; a loaded configuration, in which the cladding 30 abuts a portion of the bottom and top sides of the core 40; a rib configuration, in which the core 40 has a relatively wide bottom portion with a relatively narrow ridge portion on top of the wide bottom portion, in which the cladding 30 abuts the bottom side of the core 40; or any other desired waveguide configuration. The thickness and other dimensions of the cladding 30 and the core 40 can vary depending on the device, as is familiar to those of ordinary skill in the art.

[0054] like Figure 2 As shown, in some examples, the waveguide of the PDWA 20 defines an optical path having a double helix shape. As used herein, a double helix is ​​a shape having two spiral portions: a first portion spiraling inward toward a center and a second portion spiraling outward from the center, the two portions joining together at a transition point (usually near the center of the shape). Figure 1 , the core 40 forms an optical path extending from the input port 15 to the output port 16, wherein the optical path forms a double helix including a first helical portion 41a and a second helical portion 41b, the first helical portion spiraling inwardly from the input port 15 toward the transformation point 42, and the second helical portion spiraling outwardly from the transformation point 42 to the output port 16. In some examples, the bending radius of the core 40 along this double helical path can be maintained at least 70 μm or greater (i.e., less than or equal to 0.2 dB / cm or 0.01 dB / 90 degree bend). Wider waveguides and larger bending radii or Euler bends with appropriate adiabatic transitions can reduce straight waveguide propagation losses and curved waveguide propagation losses, respectively.

[0055] As described above, the optical path formed by the core 40 can take the form of a double helix path. A spiral, as used herein, refers to a path that repeatedly circles around a center point, forming a series of nested rings around the center point, wherein each ring (except the outermost ring) is contained within another ring. In other words, the rings gradually approach the center point if the path is traversed in one direction, or gradually move away from the center point if the path is traversed in the opposite direction. The rings of these spirals do not necessarily have to be annular or even circular, and may have straight portions. Furthermore, while the rings of the illustrated double helix have a generally rectangular shape (with rounded corners), any other desired shape may be used, such as a circle, an ellipse, a trapezoid, a pentagon, etc. In other examples, the PDWA may have a similar construction and operation to the PDWA 20 described above, except that its waveguide core portion may define a path having a shape other than a double helix, such as a straight path (not shown), a serpentine path (e.g., see Fig.11), a double serpentine path (e.g., extending in a serpentine manner in one direction from one area to a second area, and then turning back at the second area, traveling in a serpentine manner back to the original starting area) (not shown), or any other desired path.

[0056] The PDWA 20 also includes the above-mentioned input port 15 and output port 16. These ports 15 and 16 are configured to be optically coupled (and in some cases, physically connected) to the input optical fiber and the output optical fiber, respectively. Therefore, the input optical signal SIG carried on the input optical fiber in The optical signal SIG may be introduced into the core 40 of the PDWA 10 via the input port 15 and then amplified as it passes through the path defined by the core 40, and then the amplified output optical signal SIG out Outgoing from PDWA 20 to an output fiber via output port 16. Ports 15 and 16 may include edges coupled to an external lens or turning mirror (or lenses), edges coupled to a spot size transformer (e.g., a V-groove may be etched into the silicon substrate to facilitate physical attachment of the fiber at ports 15 and 16), surfaces coupled to a grating coupler or on-chip turning mirror (or lens), or any other known form of optically coupling a fiber to an optical device. Figure 2 In the illustrated example, the input port 15 and the exit port 16 are disposed on opposite edges of the optical device 10, namely, the first edge 11 and the second edge 12, respectively. In other examples discussed in more detail below, the input port and the exit port may be arranged differently, such as on two different sides that are not opposite to each other or on the same side as each other. In some examples, the waveguide core 40 is arranged so that where the core 40 meets the input port 15 or the exit port 16, the extension direction 19 of the core 40 is at an acute angle θ relative to the edge 11 or 12 of the PDWA 10. More specifically, in some examples, 0°<θ<50°. This can help reduce back reflections and suppress on-chip lasing.

[0057] Reference will be made to an optical system 70 illustrating one embodiment of an optical device 10 including a PDWA 20 in which the optical device 10 may be used. Figure 3 The operation of the PDWA 20 is described in more detail. The optical system 70 includes a pump laser 50, a wavelength division multiplexing (WDM) coupler 51, and one or more isolators 52. The pump laser 50 generates pump light configured to be absorbed by the Pr atoms and excited to an excited state. fwd For example, the pump light fwd It can be a laser with a wavelength of about 980nm. The WDM coupler 51 can receive the pump light Pump fwd And O-band signal light Sig in , and combine them into a combined optical signal output to the isolator 52. Signal light Sigin Includes coded communications and is a signal intended to be amplified; signal light Sig in , and has a wavelength in the O band (1260-1360nm). Isolator 52 prevents in Any light traveling in the reverse direction (the direction opposite to the direction of the light traveling in the forward direction) passes through the isolator 52. Such light traveling in the reverse direction may include light reflected from downstream components or spontaneous emission noise from the optical device 10. The isolator 52 allows light traveling in the forward direction (to the right in the figure) to pass. In some examples, the isolator 52 can be positioned between the pump laser 50 and the WDM coupler 51. In some examples, a second isolator (not shown) is positioned on the other side of the optical device 10 and is arranged to block any reverse direction light from components downstream of the optical device 10.

[0058] Combined Pump fwd / Sig in Then it is input to the PDWA 20 of the optical device 10. fwd The signal light Sig is absorbed by the Pr atoms in the core 40 of the PDWA 20, and its electrons are excited to an excited state. in Then it interacts with these excited Pr atoms and is amplified by stimulated emission. After emitting a photon, the excited electron drops to an intermediate state and rapidly decays to the ground state by emitting a phonon. The electrons of the Pr atoms are then pumped by the pump light that can continuously pass through the PDWA 20. fwd The Pr atoms are re-excited and the process is repeated. Gain is achieved when the population inversion between the excited and intermediate states of the Pr atoms exceeds a threshold set by on-chip losses.

[0059] In some embodiments, another pump laser 55 may be provided to provide pump light flowing through the optical device 10 in the opposite direction. rvs ,like Figure 4 This ensures that the entire length of the PDWA 20 is excited. Figure 3 If only forward pumping is used as in fwd It may be absorbed before reaching the far end of PDWA20, resulting in the Pr atoms in this region not being excited, thus potentially losing some of the amplification potential. Figure 4 In the optical system 170, the reverse direction pump light Pump rvs Ensure that the end portion of the PDWA 20 near the outlet port 16 is also fully excited, thereby maximizing the amplification. In this example, a device configured to pump rvsThe output signal Sig is directed to a second WDM coupler 54 connected to an optical interconnection at the output port 16. This optical interconnection carries the output signal Sig out The optical interconnect is the same, although the pump light rvs And the output signal Sig out will travel in the opposite direction along this shared interconnect, such as Figure 4 A second isolator 53 may also be provided between the WDM coupler 54 and the pump laser 55, and the second isolator is arranged to block light traveling in the forward direction (ie, rightward in the figure).

[0060] Now turn to Figures 5 to 22 , example optical devices 110, 210, 270, 310, 410, 510, 610, 710, 810, 910, 1010, 1110, 1210, 1310, 1410, 1510, 1610, and 1710 (or example optical systems including the same) will be described. These example optical devices include example configurations, implementations, variations, or modifications of the optical device 10 described above, and each example optical device has at least some components that are the same or similar to the components described above with respect to the optical device 10. Specifically, each of these optical devices has at least one PDWA configured to amplify O-band light, which is similar in structure and function to the PDWA 20 described above. However, the PDWAs of the various other optical devices described below may have optical paths of different shapes and / or these devices may also include additional components together with the PDWA. Unless otherwise specified (or illustrated in other ways), or unless logically contradictory, the above description of the components of the optical device 10 is also applicable to any similar components of other example optical devices described below, so repeated descriptions of these similar components are omitted below. Components of the optical devices described below that are the same or similar to the above components are given reference numerals with the same last two digits (e.g., 40 and 140).

[0061] Now turn to Figure 5 , another example optical device 110 will be described. The optical device 110 includes a PDWA 120 formed of a waveguide cladding 130 and a Pr-doped waveguide core 140. The PDWA 120 is similar to the PDWA 20 described above, except that in the PDWA 120, the input port 115 and the output port 116 are disposed on the same edge of the optical device 110. That is, both the input port 115 and the output port 116 are disposed on the first edge 111 (and no port is disposed on the second edge 112). In contrast, in the PDWA 10, the input port 15 is on the first edge 11, and the output port is on the second edge 12.

[0062] Now turn to Figure 6 , another example optical system 270 configured to implement a polarization diversity scheme is described. The optical system 270 includes Figure 6 The system 270 includes two PDWAs 20 (i.e., PDWAs 20-1 and 20-2) provided in the form of two separate optical devices 10 (i.e., optical devices 10-1 and 10-2). In other examples, the two PDWAs 20 may be provided as part of a single optical device, i.e., the two PDWAs 20 may be formed on the same chip / substrate. The system 270 is configured to be used with a communication signal utilizing a polarization diversity scheme, wherein different modes of the optical signal (i.e., TE mode and TM mode) encode different information. Therefore, the system 270 further includes a device configured to receive an input optical signal Sig having two polarization modes TE and TM. in (TE / TM), a polarization beam splitter rotator 60 that separates the TM mode into an optical path different from the optical path of the TE mode and rotates the separated TM mode to form a second TE mode. Figure 6 In the TE mode, these two TE modes are marked as TE in and TE' in ,TE in Corresponding to the original TE mode, TE' in The two TE mode signals are then transmitted through the two PDWAs of the optical devices 10-1 and 10-2, respectively, to be amplified, and are respectively used as amplified output signals TE out and TE' out The amplified output signal is then fed to the polarization rotator combiner 61, which converts the amplified signal TE out Rotate into TM mode and combine this TM mode with the amplified signal TE' out Combined to produce an amplified output signal Sig out (TE / TM), this amplified output signal has both TE and TM modes like the original input signal, but is amplified.

[0063] It should be noted that both the polarization beam splitter rotator 60 and the polarization rotator combiner 61 can be formed by devices having substantially the same structure, but these devices can be made to perform different functions depending on the manner of input signals. For example, if a signal having a combined TE / TM mode is fed as input to the first port of the device, the device operates as a beam splitter rotator and outputs TE and TE' modes from the two second ports (similar to the above-mentioned beam splitter rotator 60); however, if two TE mode signals are input to the two second ports instead, the device operates as a rotational combiner and outputs a signal having a combined TE / TM mode from the first port (similar to the above-mentioned rotational combiner 61). Therefore, in some examples, two identical instances of the same device can be used as the polarization beam splitter rotator 60 and the polarization rotator combiner 61, and the only difference between them is which signals are used as input and which ports these signals are input to. Some authors or manufacturers use the term polarization beam splitter rotator (or similar terms) as a generic name for all devices that can be used to split and rotate or rotate and combine polarized light, which means that they can use the term "polarization beam splitter rotator" (or similar terms) to refer to the device even when the device is arranged in a circuit to act as a rotator combiner. However, this article does not follow this convention and uses the terms "polarization beam splitter rotator" and "polarization rotator combiner" to more clearly explain how the device is configured to use the device.

[0064] The reason why it may be necessary to split and rotate the TM mode in some cases is that the PDWA 20 may be polarization sensitive (TE and TM modes have different mode indices and profiles), which means that different polarization dependent losses (PDL), polarization dependent dispersion (PDD) and time delays may occur, which may cause the TM mode and TE mode to become unsynchronized when passing through the PDWA 20, which may destroy the recoverability of the encoded information in the optical signal. By splitting the mode, converting the TM mode to TE and passing both through the same PDWA 20, both branches experience the same losses, dispersion and time delay, thereby ensuring that the encoded information in the output signal is not destroyed.

[0065] In some examples, rotating the TM mode into the TE mode can be achieved by separating the TM mode and the TE mode into separate fibers and physically rotating the fiber carrying the TM mode. In other examples, bulk optics can be used instead of optical fibers, such as polarization walk-off crystals or polarization beam splitters / combiners.

[0066] Now turn to Figure 7, another optical device 210 will be described. The optical device 210 includes two PDWAs 220 (i.e., PDWAs 220-1 and 220-2) formed on the same silicon substrate (not shown), or in other words, integrated together as part of the same chip. The PDWAs 220-1 and 220-2 are formed of a shared waveguide cladding 230 and two Pr-doped waveguide cores 240-1 and 240-2. (The waveguide cladding 230 is described as "shared" in the sense that the same layer of material may form the cladding for both PDWAs, but in practice, different portions of the cladding 230 layer may serve as the cladding for the respective PDWAs, and in particular, those portions of the cladding 230 that are directly adjacent to the respective cores 240-1 and 240-1 may serve as the cladding for the respective PDWAs 220-1 and 220-2.) The first PDWA 220-1 may be similar to the PDWA 20 described above, and the second PDWA 220-2 may also be similar to the PDWA 220-1, except for having mirrored optical paths (e.g., mirrored across the longitudinal centerline of the device 210). The optical device 210 further includes an integrated polarization beam splitter rotator 260 and a polarization rotator combiner 261 formed on the same substrate (as part of the same chip) as the PDWAs 220-1 and 220-2. The optical device 210 may be functionally similar to Figure 6 The optical system 270 is similar to the optical system 270 because the optical device 210 implements a polarization diversity scheme, but differs from the optical system 270 in that in the optical device 210, the polarization component and the two PDWAs are formed as part of the same chip (i.e., the same photonic integrated circuit). The input port 225 receives the optical signal Sig entering the integrated polarization beam splitter rotator 260. in (TE / TM). The integrated polarization beam splitter rotator 260 separates the TM mode and rotates it to TE' in Mode. Original TE in mode travels down along PDWA 220-2, while the separated and rotated TE' in The mode travels down along PDWA 220-1. These signals are amplified when passing through PDWA 220-1 and 220-2, and then the amplified signal TE' out and TE out The integrated polarization rotation beam combiner 261 is recombined into an amplified output signal Sig out (TE / TM), where TE out The combined output signal is converted to TM mode.

[0067] The polarization beam splitter rotator 260 and the polarization rotator combiner 261 can be formed by arranging the core waveguide sections 240-1 and 240-2 in the region of the beam splitter rotator 260 or the rotator combiner 261 so that they extend parallel to each other and the separation distance between them is small, which causes the TM mode to be optically coupled from one core section 240 to the other core section and rotated. A person of ordinary skill in the art will be familiar with how to form a beam splitter rotator or a rotator combiner by coupling two waveguides in this manner, and further details about this are therefore omitted. When the combined input signal Sig in When the (TE / TM) mode passes through the core 240-2 in the beam splitter 260, the TM mode is coupled to the adjacent core section 240-1 and rotated to TE' in signal. On the contrary, when TE out As the mode travels through combiner 261, it is coupled to core 240-1, causing TE out The signal rotates to TM mode.

[0068] Steering Figures 8 to 10 , an additional example optical device will be described that includes two PDWAs (similar to PDWA 20 or 120 described above) that are disposed in substantially the same two-dimensional area (in plan view) of the optical device and within the same vertical layer as one another. The two PDWAs are advantageously formed in the same general area by interleaving the spiral optical paths of the two PDWAs to form a parallel interleaved double helix shape.

[0069] For example, Figure 8 An example optical device 310 is shown. The optical device 310 includes PDWAs 320-1 and 320-2. The PDWAs 320-1 and 320-2 have double helices arranged to form parallel staggered double helices (eg, Figure 8 The waveguide core sections 340-1 and 340-2 are shown. Figure 8 , one of the core sections 340-1 is shown with a dotted line to make it easier to distinguish from the core section 340-2. The same cladding 330 may be shared by both PDWAs 320-1 and 320-2. The functions and other aspects of PDWAs 320-1 and 320-2 may be similar to those of PDWA 20 described above, and thus repeated descriptions thereof are omitted.

[0070] In the optical device 310, there are two O-band input optical signals Sig guided along the core portions 340-1 and 340-2, respectively. In-1 and Sig In-2 The two input ports 315-1 and 315-2 are used for the amplification of the signal. out-1 and Sig out-2The optical devices 310 are outputted via output ports 316 - 1 and 316 - 2 , respectively. In this example, input ports 315 - 1 and 315 - 2 are disposed on a first edge 311 of the optical device 310 , while output ports 316 - 1 and 316 - 2 are disposed on a second edge 312 of the optical device 310 .

[0071] In the optical device 310, the adiabatic cross 343 can be located at the center of the parallel staggered double helix. The adiabatic cross 343 includes a cross between the waveguide core portions 340-1 and 340-2. As is familiar to those skilled in the art, this cross is at right angles and is designed to avoid losses or crosstalk between the core portions 340-1 and 340-2.

[0072] Fig. 9 Another optical device 410 is illustrated. Optical device 410 includes two PDWAs 420-1 and 420-2 having parallel staggered double helix waveguide core sections 440-1 and 440-2, respectively, and a shared waveguide cladding 430. Optical device 410 may be similar to optical device 310, except that in optical device 410, input ports 415-1 and 415-2 and output ports 416-1 and 416-2 are located on the same edge 411. An adiabatic crossover 443 is also present.

[0073] Fig.10 Another optical device 510 is illustrated. Optical device 510 includes two PDWAs 520-1 and 520-2 having parallel staggered double helix waveguide core sections 540-1 and 540-2, respectively, and a shared waveguide cladding 530. Optical device 450 may be similar to optical device 410 in that input ports 515-1 and 515-2 are located on the same edge 511 as output ports 516-1 and 516-2. However, optical device 510 differs from optical device 410 in that there is no adiabatic crossing. In addition, in optical device 510, the order of ports 515 and 516 is different from the order of ports 415 and 416 in optical device 410. That is, in optical device 510, the arrangement order of the ports is (from top to bottom) 515-2 (Sig 2-in )、515-1(Sig 1-in )、516-1(Sig 1-out ) and 516-2 (Sig 2-out ), and in the optical device 410, the arrangement order of the ports is (from top to bottom) 415-1 (Sig 1-in )、415-2(Sig 2-in )、416-1(Sig 1-out ) and 416-2 (Sig 2-out). It should be noted that the difference between two devices where ports have a "1" or "2" index is not relevant here, as these indices are arbitrarily assigned and can be reversed. What is salient here is how the ports are arranged relative to each other within the respective devices. Specifically, in optical device 510, both the input port and the output port of PDWA 520-1 are located adjacent to each other (i.e., with no other ports between them), and both the input port and the output port of PDWA 520-2 have a port of PDWA 520-1 located between them. In contrast, in optical device 410, the respective input port and output port pairs of PDWAs 420-1 and 420-2 are interleaved, with each input / output pair being positioned with a port of another input / output pair between them.

[0074] Fig.11 Another optical device 610 is illustrated. Optical device 610 includes a PDWA 620 formed of a Pr-doped waveguide core 640 and a waveguide cladding 630. PDWA 620 can be similar in construction and operation to PDWA 20, except that the waveguide core 640 of PDWA 620 defines an optical path having a serpentine shape rather than a double helix shape. The serpentine shape refers to a shape that follows a path that generally extends along a first direction (e.g., direction 697) but includes repeating lateral segments that extend transversely to the first direction. The repeating lateral segments are spaced apart along the first direction, wherein consecutive lateral segments are joined together by 180 degree turns. In addition, the 180 degree turns alternate in direction with respect to each consecutive turn, and thus the path extends in alternating opposite directions with respect to each consecutive lateral segment. For example, in Fig.11 In FIG. 6 , if the path traverses from input port 615 to output port 616, the path extends in direction 699 while crossing transverse portion 695a and in direction 698 while crossing the next continuous transverse portion 695b. Fig.11The 180 degree turn is illustrated as a single smooth curve, but this is not required; in some examples, the 180 degree turn can be formed by multiple curved smaller segments that together form the 180 degree turn, with intermediate sections between the smaller curved sections. For example, two 90 degree turns connected together by an intermediate straight section can form one of the above-mentioned 180 degree turns. It should be noted that the lateral sections can be of any length and do not have to be parallel to each other or completely perpendicular to the first direction. In some examples, consecutive alternating 180 degree turns can be directly coupled to each other without a lateral section in between, and this can also be considered a serpentine shape. Although not illustrated, in some examples, the PDWA can form a double serpentine path having a first serpentine segment extending generally in a first direction and a second serpentine segment that then turns back and extends generally in a second direction opposite to the first direction, so that the input port and the output port can be on the same side of the device instead of the opposite side. In some examples with a double serpentine path, the two sections can be staggered.

[0075] Now turn to Figures 12 to 22 , various optical devices 710, 810, 910, 1010, 1110, 1210, 1310, 1410, 1510, 1610, and 1710 (or example optical systems including the same) will be described. As described above, these optical devices are configurations, implementations, variations, and / or modifications of the optical devices described above (including optical device 10). These additional optical devices are similar to optical device 10 in that they include a PDWA formed of a Pr-doped Si3N4 waveguide core portion with a SiO2 cladding on a silicon substrate. These additional optical devices differ from the previously described optical devices in that the additional optical devices further include an undoped waveguide core portion formed on the same silicon substrate as the doped waveguide core portion. The undoped core portion can be used to form various integrated optical components that can be coupled to the PDWA to form a photonic integrated optical circuit.

[0076] Now turn to Fig.12, the optical device 710 will be described. The optical device 710 includes a waveguide including a first waveguide core portion 740 and a second waveguide core portion 745 formed in the same vertical layer as each other and a cladding 730. The first waveguide core portion 740 includes Pr-doped Si3N4, similar to the waveguide portion 40 described above. In addition, the first waveguide core portion 740, together with the cladding 730 (which is similar to the cladding 30), forms a PDWA 720 that can be similar to the PDWA 20 or any other PDWA described above. However, the second waveguide core portion 745 is different from the first waveguide core portion 740 in that the second waveguide core portion 745 is undoped. That is, the second waveguide core portion 745 can include undoped Si3N4. This second waveguide core portion 745 can be used to form another optical component on the same chip as the PDWA 720 formed by the first waveguide core portion 740. Therefore, the optical device 710 can include a photonic integrated circuit. Such other optical components may include, for example, WDM couplers, polarization beam splitters, or other optical components, which will be described in more detail below.

[0077] The specific dimensions of core portions 740 and 745 and the distance between portions 740 and 745 can vary from device to device depending on the materials selected and design constraints. In some examples, in areas where core-to-core coupling is desired (such as in the case of a WDM coupler formed from two core portions), the distance between core portions 740 and 745 is about 0.5 μm to 1 μm, while in areas where core-to-core coupling is not desired, the distance between core portions 740 and 745 can be greater than 1 μm.

[0078] Now turn to Fig.13 , the optical device 810 will be described. As with the optical device 710, the optical device 810 includes a waveguide including a first waveguide core portion 840 and a second waveguide core portion 846, wherein the first waveguide core portion 840 is Pr-doped Si3N4 and the second waveguide core portion 846 is undoped Si3N4. However, unlike the optical device 710, in the optical device 810, the first waveguide portion 840 and the second waveguide portion 846 are formed in different vertical layers. Both the doped and undoped core portions 840 and 846 are at least partially surrounded by a cladding 830. In some examples, the same material is used for the cladding 830 of both the doped and undoped core portions 840 and 846, while in other examples (not shown), different materials may be used as the claddings of the doped and undoped core portions 840 and 846, respectively.

[0079] In some examples, the optical device can include a doped waveguide core (similar to the first waveguide core portion 740 or 840) and a plurality of undoped waveguide portions (similar to the second waveguide portion 745 and / or 846), wherein at least one of the undoped waveguide core portions is disposed in the same vertical layer as the doped core portion, and at least one undoped waveguide core portion is disposed in a layer different from the doped waveguide core portion. In other words, in some examples, Fig.12 and Fig.13 The configurations shown can be combined in the same optical device. Fig.21 and Fig. 22 Two non-limiting examples of this are found in .

[0080] Furthermore, in some examples (not shown), doped and undoped claddings may be used in an optical device. For example, a doped waveguide core may be bordered on one or more sides thereof by a doped cladding region, while an undoped cladding region may be disposed elsewhere in the device (e.g., adjacent to other sides of the waveguide core, or adjacent to an undoped waveguide core at another location in the optical device).

[0081] The specific dimensions of core portions 840 and 846 and the vertical distance between portions 840 and 846 may vary from device to device depending on the materials selected and design constraints. In some examples, in regions where core-to-core coupling is desired (such as in the case where a WDM coupler is formed from two core portions), the distance between core portions 840 and 846 is about 0.5 μm to 1 μm, while in regions where core-to-core coupling is not desired, the distance between core portions 840 and 846 may be greater than 1 μm.

[0082] Now turn to Fig.14 , the optical device 910 will be described. The optical device 910 is a configuration example of the optical device 710. The optical device 910 includes a PDWA 920 and two WDM couplers 951 and 954, which are all integrated on the same chip. The PDWA 920 is partially composed of Fig.12 940 is formed of a Pr-doped waveguide core 940 of an exemplary embodiment of the first waveguide core section 740 described above. On the other hand, the WDM couplers 951 and 954 are formed of undoped waveguide core sections 945 and 947 formed in the same vertical layer as the doped waveguide core 940. These undoped waveguide core sections 945 and 947 are the same as those described above with respect to Fig.12 An example implementation of the second waveguide core portion 745 is described.

[0083] More specifically, the WDM coupler 951 is formed of two undoped waveguide core sections 945 (ie, undoped core sections 945a and 945b). The undoped core section 945a is coupled to a waveguide core configured to receive a communication signal Sig to be amplified. in The undoped core portion 945b is coupled to a signal input port 925 configured to receive a forward pump light. fwd Then, the undoped core portions 945a and 945b are arranged to be parallel to each other and extend close to each other for a certain distance, which makes the pump light Pump fwd The undoped core portion 954b is coupled to the undoped core portion 945a. The specific dimensions of these portions and the distance between these portions can vary from device to device depending on the materials selected and the design constraints. In some examples, the distance between core portions 954a and 954b in their coupling region is about 0.5 μm to 1 μm. The undoped core portion 945b can then terminate at any pump light that is not coupled to the undoped core portion 945a. fwd The pump scattering region 949 is scattered. The WDM coupler 951 can also be referred to as the input end WDM coupler 951 because it receives the input optical signal Sig in .

[0084] Similarly, the WDM coupler 954 is formed by two undoped waveguide core sections 947 (ie, undoped core sections 947a and 947b). The undoped core section 947a is coupled to a waveguide core configured to output an amplified communication signal Sig out The undoped core portion 947b is coupled to a signal output port 926 configured to receive a reverse pump light Pump rvs Then, the undoped core portions 947a and 947b are arranged to be parallel to each other and extend close to each other for a certain distance, which makes the pump light Pump rvs The undoped core portion 947b is coupled to the undoped core portion 947a. The specific dimensions of these portions and the distance between these portions can vary from device to device depending on the materials selected and the design constraints. In some examples, the distance between core portions 957a and 957b in their coupling region is about 0.5 μm to 1 μm. The undoped core portion 947b can then terminate at any pump light that is not coupled to the undoped core portion 947a. rvs The pump scattering region 949 is scattered. The WDM coupler 954 can also be referred to as the output end WDM coupler 954 because it outputs the amplified output optical signal Sig out .

[0085] Doped core portion 940 is coupled to undoped core portions 945a and 947a at junctions D1 and D3. In some examples, doped core portion 940 and undoped core portions 945a and 947a can all be formed from a single continuum of Si3N4, with the difference being that dopants are added to core portion 940 and not to other portions.

[0086] When the signal light Sig in and forward pump light Pump fwd When entering the input WDM coupler 951, they are combined together into the undoped core section 945a. This combined light then leaves the WDM coupler 951 and enters the core section 940 of the PDWA 920 via the junction D1. After being amplified by the PDWA 920, the amplified signal light Sig out Then it leaves the core portion 940 of the PDWA 920 at the junction point D3 and enters the undoped core portion 947a of the WDM coupler 954. out From there, it leaves the optical device 920 via the signal output port 926. At the same time as above, the reverse pump light Pump rvs It is pumped into the PDWA 920 in the reverse direction via the output WDM coupler 954 .

[0087] although Fig.14 Optical device 910 is illustrated utilizing reverse pumping and therefore having an integrated output-end WDM coupler 954, but other example optical devices may utilize only forward pumping and may have only an integrated input-end WDM coupler similar to WDM coupler 925, while omitting the output-end WDM coupler.

[0088] Now turn to Fig.15 , another optical device 1010 will be described as another example configuration of the optical device 710. The optical device 1010 is similar to the optical device 910 described above, except that the signal output port 1026 and the reverse pump input port 1028 are located on the same edge 1011 of the device 1010 as the signal input port 1025 and the forward pump input port 1027, and therefore the output end WDM coupler 1054 is also disposed on the same side of the device 1010 as the input end 1051.

[0089] The optical device 1010 includes a PDWA 1020 and two WDM couplers 1051 and 1054 all integrated on the same chip. The PDWA 1020 is formed in part by a Pr-doped waveguide core 1040 as an example embodiment of the first waveguide core portion 740 described above, and a cladding 1030. On the other hand, the WDM couplers 1051 and 1054 are formed by undoped waveguide core portions 1045 and 1047 formed in the same vertical layer as the doped waveguide core 1040. These undoped waveguide core portions 1045 and 1047 are the same as those described above with respect to Fig.12 1045a and 1045b. The WDM coupler 1051 is similar in structure and function to the WDM couplers 951 and 947 described above. More specifically, the WDM coupler 1051 is formed of two undoped waveguide core sections 1045 (i.e., undoped core sections 1045a and 1045b). The undoped core section 1045a is coupled to a communication signal Sig to be amplified. in The undoped core portion 1045b is coupled to a signal input port 1025 configured to receive a forward pump light. fwd Similarly, the WDM coupler 1054 is formed by two undoped waveguide core sections 1047 (ie, undoped core sections 1047a and 1047b). The undoped core section 1047a is coupled to a communication signal Sig configured to output an amplified communication signal. out The undoped core portion 1047b is coupled to a signal output port 1026 configured to receive a reverse pump light Pump rvs The pump input port 1028.

[0090] Now turn to Fig.16 , another optical device 1110 will be described as another example configuration of the optical device 710. The optical device 1110 is similar to the optical device 1010 described above, except that the input-end WDM coupler 1151 has a flipped (mirrored) orientation relative to the input-end WDM coupler 1051 of the device 1010. This arrangement allows the signal input port 1125 and the output port 1127 to be located next to each other along the edge 1111.

[0091] The optical device 1110 includes a PDWA 1120 and two WDM couplers 1151 and 1154 all integrated on the same chip. The PDWA 1120 is formed in part by a Pr-doped waveguide core 1140 as an example embodiment of the first waveguide core portion 740 described above, and a cladding 1130. On the other hand, the WDM couplers 1151 and 1154 are formed by undoped waveguide core portions 1145 and 1147 formed in the same vertical layer as the doped waveguide core 1140. These undoped waveguide core portions 1145 and 1147 are the same as those described above with respect to Fig.12 1 and 11. The WDM coupler 1151 is similar in structure and function to the WDM couplers 951 and 947 described above. More specifically, the WDM coupler 1151 is formed of two undoped waveguide core sections 1145 (i.e., undoped core sections 1145a and 1145b). The undoped core section 1145a is coupled to a second waveguide core section 745 configured to receive a communication signal Sig to be amplified. in The undoped core portion 1145b is coupled to a signal input port 1125 configured to receive a forward pump light. fwd Similarly, the WDM coupler 1154 is formed by two undoped waveguide core sections 1147, namely, undoped core sections 1147a and 1147b. The undoped core section 1147a is coupled to a communication signal Sig configured to output an amplified communication signal. out The undoped core portion 1147b is coupled to a signal output port 1126 configured to receive a reverse pump light Pump rvs The pump input port 1128.

[0092] Now turn to Fig.17 , another optical device 1210 will be described as another example configuration of the optical device 710. The optical device 1210 is similar to the above-described optical device 1010, except that in the device 1210, the forward pump input port 1227 and the reverse pump input port 1228 are located adjacent to each other, and the signal input port 1225 and the output port 1226 are located adjacent to each other. This port arrangement is achieved by wrapping the undoped core portion 1247b around the periphery of the PDWA 1240 so that it can be adjacent to the undoped core portion 1247a.

[0093] The optical device 1210 includes a PDWA 1220 and two WDM couplers 1251 and 1254 all integrated on the same chip. The PDWA 1220 is formed in part of a Pr-doped waveguide core 1240 as an example embodiment of the first waveguide core portion 740 described above, and a cladding 1230. On the other hand, the WDM couplers 1251 and 1254 are formed of undoped waveguide core portions 1245 and 1247 formed in the same vertical layer as the doped waveguide core 1240. These undoped waveguide core portions 1245 and 1247 are the same as those described above with respect to Fig.12 12 is an example embodiment of a second waveguide core section 745 described herein and is similar in structure and function to the WDM couplers 951 and 947 described above. More specifically, the WDM coupler 1251 is formed of two undoped waveguide core sections 1245 (i.e., undoped core sections 1245a and 1245b). The undoped core section 1245a is coupled to a communication signal Sig to be amplified. in The undoped core portion 1245b is coupled to a signal input port 1225 configured to receive a forward pump light. fwd Similarly, the WDM coupler 1254 is formed by two undoped waveguide core sections 1247 (ie, undoped core sections 1247a and 1247b). The undoped core section 1247a is coupled to a communication signal Sig configured to output an amplified communication signal. out The undoped core portion 1247b is coupled to a signal output port 1226 configured to receive a reverse pump light Pump rvs The pump input port 1228.

[0094] Now turn to Fig.18 , another optical device 1310 will be described as another example configuration of the optical device 710. The optical device 1310 includes multiple instances of the optical device 910, but is combined together on the same substrate (integrated as part of the same chip) and arranged in an array. In other words, the optical device 910 is used as a building block or modular unit, which may be referred to as a "tile" hereinafter, and then multiple instances of this tile are arranged in an array on the same substrate to form a photonic integrated circuit capable of amplifying multiple different input optical signals (e.g., one per PDWA). Fig.18 In FIG. 4 , two such tiles are shown in a 1-dimensional array, but in other examples, any number of such tiles may be arranged together on the same chip in a 1-dimensional array or a 2-dimensional array.

[0095] More specifically, each tile or building block of the array in the optical device 1310 includes a PDWA (e.g., Fig.191 and 1320-2 in the array), input-end WDM couplers (e.g., WDM couplers 1351-1 and 1351-2), and output-end WDM couplers (e.g., WDM couplers 1354-1 and 1354-2). In some examples, if reverse pumping is not required, the output-end WDM couplers can be omitted from one, some, or all tiles in the array.

[0096] The operation of optical device 1310 is similar to that of optical device 910, except that multiple input signals (e.g., Sig in-1 and Sig in-2 ) are received and amplified by different PDWAs (e.g., PDWAs 1320-1 and 1320-2), and multiple amplified output signals (e.g., Sig out-1 and Sig out-2 ) is output. In addition, a plurality of forward pump signals and reverse pump signals may be set.

[0097] exist Fig.18 In the embodiment, the PDWA 1320-1 includes WDM couplers 1351-1 and 1354-1 all integrated on the same chip. The PDWA 1320-1 is formed in part by a Pr-doped waveguide core 1340-1 as an example embodiment of the first waveguide core portion 740 described above and a cladding 1330. On the other hand, the WDM couplers 1351-1 and 1354-1 are formed by undoped waveguide core portions 1345-1 and 1347-1 formed in the same vertical layer as the doped waveguide core 1340-1. These undoped waveguide core portions 1345-1 and 1347-1 are the undoped waveguide core portions 1345-1 and 1347-1 described above. Fig.12 1345a and 1345b. The example implementation of the second waveguide core section 745 is described and is similar in structure and function to the WDM couplers 951 and 947 described above. More specifically, the WDM coupler 1351-1 is formed of two undoped waveguide core sections (i.e., undoped core sections 1345a and 1345b). The undoped core section 1345a is coupled to a communication signal Sig to be amplified. in-1 The undoped core portion 1345b is coupled to a signal input port 1325-1 configured to receive a forward pump light Pump fwd Similarly, the WDM coupler 1354-1 is formed by two undoped waveguide core sections 1347-1 (ie, undoped core sections 1347a and 1347b). The undoped core section 1347a is coupled to a communication signal Sig configured to output an amplified communication signal. out-1 The undoped core portion 1347b is coupled to a signal output port 1326-1 configured to receive reverse pump light Pump rvs-1The WDM coupler 1351-1 is coupled to the waveguide core 1340-1 via the junction point D1. The WDM coupler 1354-1 is coupled to the waveguide core 1340-1 via the junction point D3.

[0098] exist Fig.18 In the embodiment of the present invention, the PDWA 1320-2 includes WDM couplers 1351-2 and 1354-2 all integrated on the same chip. The PDWA 1320-2 is formed in part by a Pr-doped waveguide core 1340-2 as an example embodiment of the first waveguide core portion 740 described above and a cladding 1330. On the other hand, the WDM couplers 1351-2 and 1354-2 are formed by undoped waveguide core portions 1345-2 and 1347-2 formed in the same vertical layer as the doped waveguide core 1340-2. These undoped waveguide core portions 1345-2 and 1347-2 are the undoped waveguide core portions 1345-2 and 1347-2 described above with respect to the first waveguide core portion 740. Fig.12 1345a and 1345b. in-2 The undoped core portion 1345b is coupled to a signal input port 1325-2 configured to receive a forward pump light. fwd Similarly, the WDM coupler 1354-2 is formed by two undoped waveguide core sections 1347-2 (ie, undoped core sections 1347a and 1347b). The undoped core section 1347a is coupled to a communication signal Sig configured to output an amplified communication signal. out-2 The undoped core portion 1347b is coupled to a signal output port 1326-2 configured to receive reverse pump light Pump rvs-2 The WDM coupler 1351-2 is coupled to the waveguide core 1340-2 via the junction point D2. The WDM coupler 1354-2 is coupled to the waveguide core 1340-2 via the junction point D4.

[0099] Now turn to Fig.19, an optical device 1410 will be described as another embodiment example of the optical device 710. Like the optical device 1310, the optical device 1410 includes multiple instances of an optical device similar to the optical device 910 combined together on the same chip. However, unlike the optical device 1310, in the optical device 1410, the PDWAs 1420 of the multiple optical devices are not arranged in an array, but are staggered with each other. Specifically, the doped waveguide core portions 1440-1 and 1440-2 form a parallel staggered double helix with a shared waveguide cladding 1430.

[0100] In this configuration, input-end WDM couplers 1451-1 and 1451-2 are arranged on the left side of the device 1410 and are coupled to signal input ports 1425-1 and 1425-2, respectively, and to forward pump input ports 1427-1 and 1427-2, respectively. Input-end WDM couplers 1451-1 and 1451-2 are also coupled to doped core portions 1440-1 and 1440-2, respectively, via junctions D1 and D2, respectively. In contrast, output-end WDM couplers 1454-1 and 1454-2 are arranged on the right side of the optical device 1410 and are coupled to signal output ports 1426-1 and 1426-2, respectively, and to reverse pump input ports 1428-1 and 1428-2, respectively. Output end WDM couplers 1454-1 and 1454-2 are also coupled to doped core portions 1440-1 and 1440-2, respectively, via junctions D3 and D4, respectively. In some examples, output end WDM coupler 1454 may be omitted if reverse pumping is not required.

[0101] exist Fig.19 In the embodiment of the present invention, the PDWA 1420-1 includes WDM couplers 1451-1 and 1454-1 all integrated on the same chip. The PDWA 1420-1 is formed in part by a Pr-doped waveguide core 1440-1 as an example embodiment of the first waveguide core portion 740 described above and a cladding 1430. On the other hand, the WDM couplers 1451-1 and 1454-1 are formed by undoped waveguide core portions 1445-1 and 1447-1 formed in the same vertical layer as the doped waveguide core 1440-1. These undoped waveguide core portions 1445-1 and 1447-1 are the undoped waveguide core portions 1445-1 and 1447-1 described above with respect to the first waveguide core portion 740. Fig.12 1445a and 1445b. The example implementation of the second waveguide core section 745 is described and is similar in structure and function to the WDM couplers 951 and 947 described above. More specifically, the WDM coupler 1451-1 is formed of two undoped waveguide core sections (i.e., undoped core sections 1445a and 1445b). The undoped core section 1445a is coupled to a communication signal Sig to be amplified. in-1The undoped core portion 1445b is coupled to a signal input port 1425-1 configured to receive a forward pump light Pump fwd Similarly, the WDM coupler 1454-1 is formed by two undoped waveguide core sections 1447-1 (ie, undoped core sections 1447a and 1447b). The undoped core section 1447a is coupled to a communication signal Sig configured to output an amplified communication signal. out-1 The undoped core portion 1447b is coupled to a signal output port 1426-1 configured to receive reverse pump light Pump rvs-1 The WDM coupler 1451-1 is coupled to the waveguide core 1440-1 via the junction point D1. The WDM coupler 1454-1 is coupled to the waveguide core 1440-1 via the junction point D3.

[0102] exist Fig.19 In the embodiment, the PDWA 1420-2 includes WDM couplers 1451-2 and 1454-2 all integrated on the same chip. The PDWA 1420-2 is formed in part by a Pr-doped waveguide core 1440-2 as an example embodiment of the first waveguide core portion 740 described above, and a cladding 1430. On the other hand, the WDM couplers 1451-2 and 1454-2 are formed by undoped waveguide core portions 1445-2 and 1447-2 formed in the same vertical layer as the doped waveguide core 1440-2. These undoped waveguide core portions 1445-2 and 1447-2 are the undoped waveguide core portions 1445-2 and 1447-2 described above. Fig.12 1445a and 1445b. The example implementation of the second waveguide core section 745 is described and is similar in structure and function to the WDM couplers 951 and 947 described above. More specifically, the WDM coupler 1451-2 is formed of two undoped waveguide core sections (i.e., undoped core sections 1445a and 1445b). The undoped core section 1445a is coupled to a communication signal Sig to be amplified. in-2 The undoped core portion 1445b is coupled to a signal input port 1425-2 configured to receive a forward pump light. fwd Similarly, the WDM coupler 1454-2 is formed by two undoped waveguide core sections 1447-2, namely undoped core sections 1447a and 1447b. The undoped core section 1447a is coupled to a communication signal Sig configured to output an amplified communication signal. out-2 The undoped core portion 1447b is coupled to a signal output port 1426-2 configured to receive a reverse pump light Pump rvs-2The WDM coupler 1451-2 is coupled to the waveguide core 1440-2 via the junction point D2. The WDM coupler 1454-2 is coupled to the waveguide core 1440-2 via the junction point D4.

[0103] Now turn to Fig. 20 , an optical device 1510 will be described as another embodiment example of the optical device 710. As with the optical device 910, the optical device 1510 includes doped and undoped waveguide core portions disposed in the same vertical layer of the same chip. However, unlike the optical device 910, in the optical device 1510, there are two doped waveguide core portions 1540-1 and 1540-2 that form two different PWDAs 1520-1 and 1520-2 (having a shared waveguide cladding 1530). Furthermore, in the optical device 1510, in addition to forming WDM couplers 1545-1, 1545-2, 1547-1, and 1547-2, the undoped waveguide portion also forms an integrated polarization beam splitter rotator 1560 and a rotator combiner 1561.

[0104] The integrated polarization beam splitter 1560 can be similar in construction and operation to the integrated polarization beam splitter 260 described above, except that the integrated polarization beam splitter 1560 is formed by undoped waveguide core portions 1563a and 1563b instead of doped waveguide cores. In addition, the two undoped waveguide core portions 1563a and 1563b are coupled to two input-end WDM couplers 1551-1 and 1551-2, respectively. These input-end WDM couplers 1551-1 and 1551-2 are also integrated into the same chip and are similar to the input-end WDM coupler 951 of the device 910. The input-end WDM couplers 1551-1 and 1551-2 are coupled to the doped core portions 1540-1 and 1540-2, respectively, via junctions D1 and D2, respectively.

[0105] Similarly, the integrated polarization combiner 1561 can be similar in construction and operation to the integrated polarization beam splitter 261 described above, except that the integrated polarization combiner 1561 is formed by an undoped waveguide core portion (not labeled) instead of a doped waveguide core. In addition, the two undoped waveguide core portions are coupled to two output end WDM couplers 1554-1 and 1554-2, respectively. These output end WDM couplers 1554-1 and 1554-2 are integrated into the same chip and are similar to the output end WDM coupler 954 of the device 910. The output end WDM couplers 1554-1 and 1554-2 are coupled to the doped core portions 1540-1 and 1540-2, respectively, via junctions D3 and D4, respectively.

[0106] The optical device 1510 can be operated as follows. With TM and TE modes Sig in The signal light (TE / TM) is input into the polarization beam splitter 1560 via the port 1525 and is separated into two TE mode signals TE in (guided along the undoped core portion 1563b) and TE' in (guided along core portion 1563a). Signal TE in Then it is input into the undoped core portion 1545a of the WDM coupler 1551-2, and the signal TE' in is input into the undoped core portion 1545a of the WDM coupler 1551-1. At the same time, the forward pump light Pump fwd-1 and Pump fwd-2 The forward pump light in the core portion 1545b of the WDM coupler 1551-1 is input into the undoped core portion 1545b of the WDM coupler 1551-1 and 1551-2 via the ports 1527-1 and 1527-2, respectively. fwd-1 Coupled to the core portion 1545a of the WDM coupler 1551-1, thereby connecting to the TE' in The signals are joined, and this combined signal is transmitted into the doped waveguide section 1540-1 via the joining point D1. Similarly, the forward pump light Pump in the core section 1545b of the WDM coupler 1551-2 fwd-2 is coupled to the core portion 1545a of the WDM coupler 1551-2, thereby connecting to the TE in The signals are joined, and the combined signal is transmitted into the doped waveguide portion 1540-2 via the junction point D2. rvs-1 and Pump rvs-2 It is also injected into PDWA 1520-1 and 1520-2 simultaneously via ports 1528-1 and 1528-2 and WDM couplers 1554-1 and 1554-2. Signal TE' in and TE in The amplified output signal TE′ is amplified when passing through the doped core portions 1540-1 and 1540-2, and the amplified output signal TE′ out and TE out Then the signal Sig is finally combined by the polarization rotator combiner 1561 out (TE / TM) and is output from device 1510 via port 1526.

[0107] Now turn to Fig.21, an optical device 1610 will be described as an implementation example of the optical device 810. The optical device 1610 is similar to the optical device 910 in that the optical device 1610 includes a PDWA 1620 and two integrated WDM couplers 1651 and 1654 all integrated on the same chip, and includes doped and undoped waveguide core portions. Specifically, the PDWA 1620 is formed of a doped waveguide core 1640 together with a waveguide cladding 1630, and the WDM couplers 1651 and 1654 are formed of undoped waveguide core portions 1645, 1646, 1647, and 1648 together with the waveguide cladding 1630. However, the optical device 1610 is different from the optical device 910 in that the undoped waveguide core portion includes some undoped waveguide core portions 1646 and 1648 located in a vertical layer different from the doped waveguide core portion 1640. These undoped waveguide core portions 1646 and 1648 are Fig.13 An example implementation of the second waveguide core portion 846 is described.

[0108] More specifically, the WDM coupler 1651 is formed of an undoped waveguide core portion 1645 formed in the same vertical layer as the doped waveguide core portion 1640 and an undoped waveguide core portion 1646 positioned in a vertical layer different from both the doped waveguide core portion 1640 and the undoped waveguide core portion 1645. (The core portion 1646 is formed in the vertical layer of the doped waveguide core portion 1640.) Fig.21 ) The undoped core portion 1645 is coupled to the edge 1611 and is configured to receive the communication signal Sig to be amplified. in The undoped core portion 1646 is coupled to a signal input port 1625 configured to receive a forward pump light. fwd The pump input port 1627. Fig.21 As shown, there is a region where the undoped core portions 1645 and 1646 overlap each other and extend very close to each other in parallel, thereby allowing the pump light Pump fwd The undoped core portion 1646 is coupled to the undoped core portion 1645 .

[0109] Similarly, the WDM coupler 1654 is formed by an unopened waveguide portion 1647 in the same layer as the doped core portion 1640 and another undoped waveguide portion 1648 in a different layer from these. There is a region where these undoped core portions 1648 and 1647 vertically overlap each other and extend parallel to and close to each other, thereby allowing the reverse pump signal Pump rvs The undoped core portion 1648 is coupled to the core portion 1647. The portion 1648 is coupled to the edge 1612 for receiving the reverse pump light Pump rvsThe reverse pump port 1628 of the embodiment of the present invention is coupled to the portion 1654 of the present invention, and the portion 1654 is coupled to the output amplified signal light Sig located on the edge 1612. out The outlet portion 1647.

[0110] Now turn to Fig. 22 , another optical device 1710 will be described as another embodiment example of the optical device 810. The optical device 1710 is similar to the optical device 1510 in that the optical device 1610 includes a plurality of PDWAs, WDM couplers, and polarization beam splitters / combiners all integrated on the same chip, wherein the PDWA is formed of a Pr-doped waveguide core portion and the other components are formed of an undoped waveguide core portion. The optical device 1710 is different from the optical device 1510 in that, in the optical device 1710, some undoped waveguide core portions are formed in a vertical layer different from the doped waveguide core portions.

[0111] Specifically, PDWAs 1720-1 and 1720-2 are formed by Pr-doped waveguide sections 1740-1 and 1740-2 together with a waveguide cladding 1730. Fig. 22 The undoped core portions 1746a-1, 1746a-2, 1746b-1, and 1746b-2 indicated by the dashed lines in FIG. are formed in a different vertical layer from the doped core portions 1740-1 and 1740-2. In addition, the undoped core portions 1745a-1, 1745a-2, 1747-1, and 1747-2 are formed in the same vertical layer as the doped core portions 1740-1 and 1740-2.

[0112] The first input end WDM coupler 1751-1 is formed by a portion of the undoped core portion 1746a-1 and a portion of the undoped core portion 1745a-1; specifically, the WDM coupler 1751-1 is formed in a region in which the undoped core portions 1746a-1 and 1745a-1 extend parallel to each other, vertically overlap, and are relatively close to each other, so that the pump light Pump received from the port 1727-1 fwd-1 The undoped core portion 1746a-1 may be coupled to the undoped core portion 1745a-1. The second input end WDM coupler 1751-2 is similarly formed by a portion of the undoped core portion 1746a-2 and a portion of the undoped core portion 1745a-2, so that the pump light Pump received from the input port 1728-2 fwd-2 The undoped core portion 1746a-2 may be coupled into the undoped core portion 1745a-2.

[0113] In a similar manner, the first output end WDM coupler 1754-1 is formed by a portion of the undoped core portion 1746b-1 and a portion of the undoped core portion 1747-1; specifically, the WDM coupler 1754-1 is formed in a region where the undoped core portions 1746b-1 and 1747-1 extend parallel to each other, vertically overlap, and are relatively close to each other, so that the reverse pump light Pump received from the port 1728-1 rvs-1 The undoped core portion 1746b-1 may be coupled to the undoped core portion 1747-1. The second output end WDM coupler 1754-2 is similarly formed by a portion of the undoped core portion 1746b-2 and a portion of the undoped core portion 1747-2, so that the reverse pump light Pump received from the input port 1728-2 rvs-2 The undoped core portion 1746b-2 may be coupled into the undoped core portion 1747-2.

[0114] Polarization beam splitter 1760 and beam combiner 1762 may be formed and operated in the same manner as polarization beam splitter 1560 and beam combiner 1562, respectively.

[0115] like Fig. 22 As shown, pump ports 1727-1, 1727-2, 1728-1, and 1728-2 are all located along the same edge 1711 of optical device 1710, while output end WDM couplers 1754-1 and 1754-2 are located near the opposite edge 1712. Therefore, undoped core portions 1746b-1 and 1746b-2 need to extend across device 1710 to reach output end WDM couplers 1754-1 and 1754-2. Such routing of the undoped core portions 1746b-1 and 1746b-2 across the device 1710 may be more challenging, may require a larger area of ​​the device 1710, and / or may require different locations for the pump ports 1727-1, 1727-2, 1728-1, and 1728-2 if the undoped core portions 1746b-1 and 1746b-2 are in the same vertical layer as the doped core portion 1740. However, since the undoped core portions 1746b-1 and 1746b-2 are in a different vertical layer than the doped core portion 1740, it is relatively easy to route the undoped core portions 1746b-1 and 1746b-2 across the device 1710 while maintaining a relatively compact footprint and desired pump port placement.

[0116] As discussed above, in some examples, multiple "tiles" may be arranged together on the same substrate (in a one-dimensional array or a two-dimensional array), each "tile" including at least one waveguide optical amplifier (and in some cases additional components). Fig.18One such example is illustrated, in which a plurality of tiles corresponding in layout to the optical device 910 are arranged on the same substrate. However, in other examples (not illustrated), tiles corresponding in layout to other optical devices in the optical devices disclosed herein may be arranged on the same substrate in a similar manner. For example, a plurality of tiles of any one of the optical devices 10, 210, 310, 410, 510, 610, 710, 810, 910, 1010, 1110, 1210, 1410, 1510, 1610, or 1710 described above may be arranged in a similar manner. Fig.18 In addition, although in order to simplify the illustration, Fig.18 Only two tiles are shown in the array, but any number of tiles may be included in the array. Fig.18 The tiles are arranged vertically, but they can be arranged to extend horizontally or in a two-dimensional array (e.g., a grid) with rows and columns of tiles. Fig.18 In the embodiment of the present invention, the same type of tiles are used in the array, but this is not necessarily the case, and different tiles corresponding to different optical devices in the optical devices disclosed herein can be mixed and matched as desired. For example, tiles corresponding to optical device 910 and tiles corresponding to optical device 1510 (or any other optical device in the disclosed optical devices) can be arranged together on the same substrate.

[0117] Now turn to Fig.23 , an example optical device 1810 will be described. The optical device 1810 includes two doped waveguide amplifier sections 1821-1 and 1821-2 disposed on the same substrate 1815 but in different vertical layers from each other. In some examples, the doped waveguide amplifier sections 1821-1 and 1821-2 form separate respective doped waveguide amplifiers that happen to be integrated onto the same chip but amplify different signals respectively. In other examples, the doped waveguide amplifier sections 1821-1 and 1821-2 form a single doped waveguide amplifier (e.g., they are two parts of the same amplifier).

[0118] Each doped waveguide amplifier section 1821-1 and 1821-2 is formed of a doped waveguide core and a cladding at least partially surrounding the core. Specifically, the doped waveguide amplifier section 1821-1 includes a doped waveguide core 1881, and the doped waveguide amplifier section 1821-2 includes a doped waveguide core 1882. In the illustrated example, both the doped waveguide amplifier sections 1821-1 and 1821-2 have the same waveguide cladding 1830, but in other examples, different cladding materials may be used for the respective doped waveguide amplifier sections 1821-1 and 1821-2.

[0119] In an example, substrate 1815 includes silicon (Si) or glass, and cladding 1830 and cores 1881 and 1882 are formed of a silicon-based material. In an example, cladding 1830 includes silicon dioxide (SiO2), and each of cores 1881 and 1882 includes a rare earth element (in Fig.23 Examples of suitable rare earth elements for doping core 1881 or 1882 include praseodymium (Pr), erbium (Er), ytterbium (Yb), etc. In some examples, the same rare earth element is used to dope both cores 1881 and 1882, while in other examples, different rare earth elements are used to dope cores 1881 and 1882, respectively. Figure 24 to Figure 29 The examples are described in more detail.

[0120] The specific dimensions of portions 1881 and 1882 and the vertical distance between portions 1881 and 1882 may vary from device to device depending on the materials selected and the design constraints. In some examples, in areas where core-to-core coupling is desired (such as in the case of forming a vertical coupler), the distance between core portions 1881 and 1882 is about 0.5 μm to 1 μm, while in areas where core-to-core coupling is not desired, the distance between core portions 1881 and 1882 may be greater than 1 μm.

[0121] Figure 24 to Figure 26 An optical device 1910 is illustrated as an example implementation of the optical device 1810. The optical device 1910 includes a plurality of layers vertically stacked atop a substrate (not shown), including at least a first layer 1910a and a second layer 1910b vertically stacked on the first layer 1910a. Fig.24 A plan view of the optical device 1910 with all layers is shown, and Fig.25 and Fig.26 Plan views of isolated first and second layers 1910a and 1910b are illustrated, respectively.

[0122] In the example optical device 1910, there are two doped waveguide amplifier sections 1921-1 and 1921-2 formed in layers 1910a and 1910b, respectively. Although formed in different layers, the doped waveguide amplifier sections 1921-1 and 1921-2 are two sections of the same waveguide amplifier 1920. The doped waveguide amplifier section 1921-1 includes a first doped waveguide core section 1981 (together with the cladding 1930) as an example of a waveguide core section 1981. The doped waveguide amplifier section 1921-2 includes a second doped waveguide core section 1982 (together with the cladding 1930) as an example of a waveguide core section 1982. The waveguide core portions 1981 and 1982 are optically coupled by an adiabatic vertical coupler 1983 including a first portion 1983a of the waveguide core 1981 and a second portion 1983b of the waveguide core 1982 arranged parallel to each other, vertically overlapping, and relatively close to each other (small vertical separation distance), so that light from the waveguide core portion 1981 is coupled to the waveguide core portion 1982 while passing through the adiabatic vertical coupler 1983. The specific dimensions of these portions and the distance between these portions can vary from device to device depending on the selected materials and design constraints. In some examples, the distance between the core portions 1981 and 1982 in the adiabatic vertical coupler 1983 is about 0.5 μm to 1 μm. In some examples, other portions of the amplifier portions 1981 and 1982 outside the coupler 1983 can be separated by a larger separation distance to prevent accidental coupling between them. In some examples, the vertical separation distance outside of coupler 1983 can be greater than 1 μm, and in some examples, between 1 μm and 10 μm.

[0123] By vertically stacking waveguide amplifier sections 1981 and 1982, the overall length of waveguide amplifier 1920 can be greatly increased without increasing the footprint of the waveguide amplifier (footprint refers to the 2D area occupied in a plan view). Although this does make the chip thicker in the vertical direction, increasing the thickness of the chip can sometimes be less costly than increasing the footprint of the chip. Although only two stacked amplifier sections are illustrated, any number of amplifier sections stacked vertically in any number of layers can be used to form a given amplifier.

[0124] In the illustrated example, the optical device 1910 further includes an integrated input WDM coupler 1951 and an output WDM coupler 1954 constructed in a manner similar to the other input WDM couplers and output WDM couplers described above. However, in this example, the input WDM coupler 1951 and the output WDM coupler 1954 can be formed in different vertical layers from each other. For example, the input WDM coupler 1951 can be formed in the first layer 1910a, while the output WDM coupler 1954 is formed in the second layer 1910b. In another example, one or both of the WDM couplers can be omitted. Although not shown, other optical components can also be integrated into the optical device 1910, such as polarization beam splitters and combiners similar to those described above.

[0125] In some examples, both core portions 1981 and 1982 are doped with Pr, and thus amplifier 1920 is a PDWA that amplifies O-band light. in Includes O-band light, and Pump fwd and Pump rvs Includes light with a wavelength of approximately 980nm.

[0126] In other examples, both core portions 1981 and 1982 are doped with Er, and thus amplifier 1920 is an EDWA that amplifies C-band light. in Including C-band light, and Pump fwd and Pump rvs The EDWA 1920 may include light having a wavelength of about 980 nm or 1480 nm. Such an EDWA 1920 differs from existing EDWAs at least in that it includes two portions formed in different vertical layers. In addition, examples in which the EDWA 1920 has an integrated WDM coupler or other integrated components formed on the same chip may also differ from existing EDWAs at least by having other integrated optical components. The EDWA 1920 may also differ from existing EDWAs in the shape of its waveguide core portions 1981 and 1982. Additionally, similar to any of the above-described example ODWAs, the EDWA 1920 may incorporate an undoped region in which a passive optical component (such as an integrated WDM coupler) may be formed.

[0127] In other examples, both core portions 1981 and 1982 are doped with some other rare earth elements, and / or can amplify light in bands other than the O-band or the C-band.

[0128] Figure 27 to Figure 29An optical device 2010 is illustrated as an example implementation of the optical device 1810. The optical device 2010 includes a plurality of layers vertically stacked atop a substrate (not shown), including at least a first layer 2010a and a second layer 2010b vertically stacked on the first layer 2010a. Fig. 27 A plan view of the optical device 2010 with all layers is shown, and Fig.28 and Fig.29 Plan views of isolated first and second layers 2010a and 2010b are illustrated, respectively.

[0129] As with the optical device 1910, in the example optical device 2010, there are two doped waveguide amplifier sections 2021-1 and 2021-2 formed in layers 2010a and 2010b, respectively. Unlike the optical device 1910, in the optical device, the doped waveguide amplifier sections 2021-1 and 2021-2 form two separate waveguide amplifiers 2020-1 and 2020-2, respectively. The doped waveguide amplifier section 2021-1 includes a first doped waveguide core section 2081 (together with the cladding 2030) as an example of a waveguide core section 2081. The doped waveguide amplifier section 2021-2 includes a second doped waveguide core section 2082 (together with the cladding 2030) as an example of a waveguide core section 2082. By vertically stacking the waveguide amplifiers 1920-1 and 1920-2, multiple amplifiers can be placed within the same footprint as a single amplifier.

[0130] In the illustrated example, the optical device 2010 further includes integrated input-end WDM couplers 2051-1, 2051-2 and output-end WDM couplers 2054-1, 2054-2 constructed in a manner similar to the other input-end WDM couplers and output-end WDM couplers described above. The WDM couplers 2051-1 and 2054-1 are disposed in the first layer 2010a and coupled to opposite sides of the waveguide core portion 2081, while the WDM couplers 2051-2 and 2054-2 are disposed in the second layer 2010b and coupled to opposite sides of the waveguide core portion 2082. In other examples, some or all of the WDM couplers may be omitted. Although not illustrated, other optical components may also be integrated into the optical device 2010, such as polarization beam splitters and combiners similar to those described above.

[0131] In some examples, both core portions 2081 and 2082 are doped with the same rare earth element as each other. In one example, both core portions 2081 and 2082 are doped with Pr, and thus amplifiers 2020 are both PDWAs that amplify separate O-band optical signals. In such an example, Sig in-1 and Signin-2 Including O-band signal, and Pump fwd-1 、Pump fwd-2 、Pump rvs-1 and Pump rvs-2 A pump light having a wavelength of about 980 nm may be included. In other examples, both core portions 2081 and 2082 are doped with Er, and thus amplifier 2010 is an EDWA that amplifies C-band light. In such an example, Sig in-1 and Sign in-2 Including C-band signal, and Pump fwd-1 、Pump fwd-2 、Pump rvs-1 and Pump rvs-2 Pump light having a wavelength of about 980 nm or 1480 nm may be included. Such an EDWA 2010 differs from existing EDWAs at least in that it includes two parts formed in different vertical layers. In addition, examples in which the EDWA 2010 has an integrated WDM coupler or other integrated components formed on the same chip may also differ from existing EDWAs at least by having other integrated optical components. The EDWA 1820 may also differ from existing EDWAs in the shape of its waveguide core parts 2081 and 2082. In other examples, both the core parts 2081 and 2082 are doped with some other rare earth elements, and / or may amplify light in a band different from the O-band or the C-band.

[0132] In some examples, core portions 2081 and 2082 are doped with rare earth elements that are different from each other. In one example, core portion 2081 is doped with Pr, and thus amplifier 2020-1 is a PDWA, while core portion 2082 is doped with Er, and thus amplifier 2020-2 is an EDWA. In such an example, Sig in-1 Including O-band signal, Sig in-2 Including C-band signal, Pump fwd-1 and Pump rvs-1 Includes wavelengths of about 980nm, and Pump fwd-2 and Pump rvs-2 Including wavelengths of about 980nm or 1480nm.In other examples, core portions 2081 and 2082 are doped with other rare earth elements.

[0133] The specific dimensions of these portions and the distances between these portions may vary from device to device depending on the materials chosen and the design constraints.In some examples, the vertical distance between core portions 2081 and 2082 is greater than 1 μm, and in some examples, between 1 μm and 10 μm.

[0134] Despite Figure 27 to Figure 29 Only two stacked amplifiers are shown in , but any number of amplifiers may be stacked vertically in any number of layers in this manner. Also, although not shown, multilayer amplifiers including waveguides formed in multiple vertical layers (such as amplifier 1920) may also be stacked vertically on top of each other on the same chip in a similar manner. Figure 27 to Figure 29 In the drawings, each of layers 2010a and 2010b includes a waveguide amplifier 2020-1 or 2020-2 and other optical components arranged in a configuration similar to that of optical device 910, but this is merely one example, and in other examples, the waveguide amplifiers and / or other optical components in the layers may be arranged according to any of the configurations similar to any of the above-described optical devices.

[0135] Now turn to Fig.30 , an example optical device 2110 will be described. The optical device 2110 includes a doped waveguide core portion 2181 and an undoped waveguide core portion 2145 disposed on the same substrate 2115 in the same vertical layer. The optical device 2110 is similar to the above-described optical device 710, except that in the optical device 2110, the doped waveguide core portion 2181 is not limited to being doped with Pr. Instead, the waveguide core portion 2181 may be doped with any rare earth element (such as Er, Yb, or others). The doped waveguide core portion 2181 and the cladding 2130 together form a waveguide optical amplifier 2120 similar to any of the waveguide optical amplifiers described above. The undoped core portion 2145 may form another optical component, such as a WDM coupler, a polarization beam splitter / combiner, or any other optical component integrated into the same photonic integrated circuit as the doped waveguide core portion 2181. In various examples, the optical device 2110 may be similar to Figures 14 to 21 The optical devices 910, 1010, 1110, 1210, 1310, 1410 and 1510 illustrated in FIG. 1 are configured in a manner similar to any one of the optical devices 910, 1010, 1110, 1210, 1310, 1410 and 1510 illustrated in FIG. 1 , except that the Pr-doped core portion is replaced by a waveguide core portion 2181 doped with another rare earth element.

[0136] The specific dimensions of these portions 2181 and 2145 and the distance between portions 2181 and 2145 can vary from device to device depending on the materials selected and design constraints. In some examples, in areas where core-to-core coupling is desired (such as in the case of forming a WMD coupler), the distance between core portions 2181 and 2145 is about 0.5 μm to 1 μm, while in areas where core-to-core coupling is not desired, the distance between core portions 2181 and 2145 can be greater than 1 μm.

[0137] Now turn to Fig.31, an example optical device 2210 will be described. The optical device 2210 includes a doped waveguide core portion 2281 and an undoped waveguide core portion 2246 disposed on the same substrate 2215 in different vertical layers. The optical device 2210 is similar to the optical device 810 described above, except that in the optical device 2210, the doped waveguide core portion 2281 is not limited to being doped with Pr. Instead, the waveguide core portion 2281 can be doped with any rare earth element (such as Er, Yb, or others). The doped waveguide core portion 2281 and the cladding 2230 together form a waveguide optical amplifier 2220 similar to any of the waveguide optical amplifiers described above. The undoped core portion 2246 can form another optical component, such as a WDM coupler, a polarization beam splitter / combiner, or any other optical component integrated into the same photonic integrated circuit as the doped waveguide core portion 2281. In various examples, the optical device 2210 can be similar to Fig.21 and Fig. 22 Either of the illustrated optical devices 1610 and 1710 is configured except that the Pr-doped core portion is replaced by a waveguide core portion 2181 doped with another rare earth element.

[0138] The specific dimensions of these portions 2246 and 2281 and the vertical distance between portions 2246 and 2281 can vary from device to device depending on the materials selected and the design constraints. In some examples, in areas where core-to-core coupling is desired (such as in the case of forming a WMD coupler), the distance between core portions 2246 and 2281 is about 0.5 μm to 1 μm, while in areas where core-to-core coupling is not desired, the distance between core portions 2246 and 2281 can be greater than 1 μm.

[0139] Examples disclosed herein include but are not limited to at least the following configurations:

[0140] (1) An optical device comprising: a substrate; and a waveguide optical amplifier, the waveguide optical amplifier being formed on the substrate and comprising: a core defining an optical path through the waveguide optical amplifier; and a cladding adjacent to at least one side of the core, wherein the core comprises silicon nitride (Si3N4) doped with praseodymium (Pr), so that under the condition that pump light and O-band signal light pass through the waveguide optical amplifier, the waveguide optical amplifier amplifies the O-band signal light.

[0141] (2) The optical device according to Configuration 1, wherein the substrate is silicon, and the cladding is silicon oxide.

[0142] (3) The optical device according to Configuration 1, wherein the cladding surrounds the core in a cross section transverse to the optical path.

[0143] (4) The optical device according to Configuration 1, wherein the optical path defined by the core includes a double helix.

[0144] (5) An optical device as described in configuration 4 includes: an input end, which is located at a first edge of the optical device and is used to optically couple an input optical fiber to the core; and an output end, which is located at a second edge of the optical device and is used to optically couple an output optical fiber to the core, the second edge being opposite to the first edge.

[0145] (6) The optical device as described in configuration 4 includes: an input end, which is located at the first edge of the optical device and is used to optically couple the input optical fiber to the core; and an output end, which is located at the first edge of the optical device and adjacent to the input end and is used to optically couple the output optical fiber to the core.

[0146] (7) An optical device as described in any of Configurations 5 or 6, wherein the optical path extends along a first direction at the input end and extends along a second direction at the output end, wherein the first direction and the second direction are not perpendicular to either of the first edge and the second edge.

[0147] (8) An optical device as described in configuration 1, comprising: a second waveguide optical amplifier, the second waveguide optical amplifier being formed on the substrate and comprising: a second core, the second core defining a second optical path through the waveguide, and a second cladding, the second cladding being adjacent to at least one side of the second core, wherein the second core comprises silicon nitride (Si3N4) doped with praseodymium (Pr), so that under the condition that the pump light and the second O-band signal light pass through the second waveguide, the second waveguide amplifies the second O-band signal light.

[0148] (9) The optical device according to Configuration 8, wherein the waveguide and the second waveguide are adjacent to each other in the same vertical layer on the substrate.

[0149] (10) The optical device according to Configuration 8, wherein the waveguide and the second waveguide are staggered with each other in the same vertical layer on the substrate.

[0150] (11) The optical device of Configuration 10, wherein the optical path defined by the core includes a first double helix; and wherein the second optical path defined by the second core includes a second double helix.

[0151] (12) The optical device of Configuration 11, wherein the core intersects the second core at an adiabatic intersection at a common center of the first double helix and the second double helix.

[0152] (13) An optical device as described in configuration 10 includes: a first input end and a first output end, wherein the first input end and the first output end are coupled to the core; and a second input end and a second output end, wherein the second input end and the second output end are coupled to the second core, wherein the first input end and the second input end are disposed on a first edge of the optical device, and wherein the first output end and the second output end are disposed on a second edge of the optical device, and the second edge is opposite to the first edge.

[0153] (14) An optical device as described in configuration 10, a first input end and a first output end, the first input end and the first output end are coupled to the core; and a second input end and a second output end, the second input end and the second output end are coupled to the second core, wherein the first input end, the second input end, the first output end and the second output end are arranged on a first edge of the optical device.

[0154] (15) The optical device according to Configuration 1, wherein the optical path defined by the core includes a serpentine shape.

[0155] (16) An optical device as described in configuration 1, wherein the waveguide optical amplifier includes a second core defining a second optical path, wherein the optical device includes a first polarization beam splitter rotator, the first polarization beam splitter rotator is configured to separate the first polarization mode and the second polarization mode of the signal light, guide the first mode downward along the optical path, and guide the second mode downward along the second optical path; and wherein the optical device includes a second polarization beam splitter rotator, the second polarization beam splitter rotator is configured to recombine the first mode and the second mode.

[0156] (17) An optical device comprising: a substrate; and a first waveguide core portion, the first waveguide core portion being formed on the substrate and comprising silicon nitride (Si3N4) doped with a rare earth element; a second waveguide core portion, the second waveguide core portion being formed on the substrate and comprising undoped silicon nitride (Si3N4) and optically coupled to the first core portion; and a cladding, the cladding being adjacent to the first waveguide core portion and the second waveguide core portion, wherein, under a condition in which pump light and signal light pass through the first waveguide core portion, the first waveguide core portion amplifies the signal light.

[0157] (18) An optical device as described in configuration 17, wherein the second waveguide core section forms a wavelength division multiplexing (WDM) coupler, and the WDM coupler is configured to receive the pump light and the signal light and guide the pump light and the signal light into the first waveguide core section.

[0158] (19) An optical device as described in configuration 18, wherein the second waveguide core portion includes a first segment and a second segment, the first segment is configured to receive the signal light, and the second segment is configured to receive the pump light, wherein the first segment is directly connected to the first core portion, and the second segment is arranged to optically couple the pump light from the second segment into the first segment.

[0159] (20) The optical device according to Configuration 19, wherein the first waveguide core portion and the second waveguide core portion are arranged in the same vertical layer.

[0160] (21) The optical device according to Configuration 19, wherein the first waveguide core portion and the second waveguide core portion are arranged in different vertical layers.

[0161] (22) An optical device as described in configuration 18, comprising: a third waveguide core portion, the third waveguide core portion comprising undoped silicon nitride (Si3N4) and optically coupled to the first waveguide core portion, wherein, in the optical path of the signal light through the optical device, the second waveguide core portion is located upstream of the first waveguide core portion, and the first waveguide core portion is located upstream of the third waveguide core portion, and wherein the third waveguide core portion forms a second WDM coupler, the second WDM coupler being configured to: receive a second pump light and guide the second pump light into the first waveguide core portion to travel backward through the first waveguide core portion, and receive an amplified signal light from the first waveguide core portion and guide the amplified signal light to an output end of the optical device.

[0162] (23) An optical device as described in configuration 22, wherein the WDM coupler includes a first input end for receiving the signal light and a second input end for receiving the pump light, and the first input end and the second input end are arranged adjacent to each other on a first edge of the optical device; wherein the second WDM coupler includes a first output end for outputting the signal light and a third input end for receiving the second pump light, and the first output end and the third input end are arranged adjacent to each other on a second edge of the optical device.

[0163] (24) An optical device as described in configuration 22, wherein the WDM coupler includes a first input end for receiving the signal light and a second input end for receiving the pump light, and the first input end and the second input end are arranged adjacent to each other on a first edge of the optical device; wherein the second WDM coupler includes a first output end for outputting the signal light and a third input end for receiving the second pump light, and the first output end and the third input end are arranged adjacent to each other on the first edge of the optical device.

[0164] (25) An optical device as described in configuration 22, wherein the WDM coupler includes a first input end for receiving the signal light and a second input end for receiving the pump light; wherein the second WDM coupler includes a first output end for outputting the signal light and a third input end for receiving the second pump light, wherein the first input end, the second input end and the third input end are continuously arranged adjacent to each other on a first edge of the optical device, wherein the first output end is arranged adjacent to the first input end.

[0165] (26) The optical device according to configuration 17, wherein the rare earth element includes praseodymium (Pr), and the signal light is in an O band.

[0166] (27) The optical device according to Configuration 17, wherein the rare earth element includes erbium (Er), and the signal light is in a C band.

[0167] (28) An optical device as described in configuration 17, comprising: a fourth waveguide core portion, the fourth waveguide core portion comprising silicon nitride (Si3N4) doped with a second rare earth element; a fifth waveguide core portion, the fifth waveguide core portion comprising undoped silicon nitride (Si3N4) and optically coupled to the fourth waveguide core portion; wherein the cladding is adjacent to the fourth waveguide core portion and the fifth waveguide core portion, wherein, under the condition that a second pump light and a second signal light pass through the fourth waveguide core portion, the fourth waveguide core portion amplifies the second signal light.

[0168] (29) The optical device according to Configuration 28, wherein the first waveguide core portion and the fourth waveguide core portion are adjacent to each other in the same vertical layer on the substrate.

[0169] (30) The optical device according to Configuration 28, wherein the first waveguide core portion and the fourth waveguide core portion are staggered with each other in the same vertical layer on the substrate.

[0170] (31) The optical device of configuration 30, wherein the first waveguide core forms a first double helix; and wherein the fourth waveguide core forms a second double helix that is parallel and staggered with the first double helix.

[0171] (32) The optical device according to Configuration 28, wherein the first waveguide core portion and the fourth waveguide core portion are vertically stacked in different vertical layers on the substrate.

[0172] (33) The optical device as described in configuration 17 includes: a third waveguide core portion, the third waveguide core portion defining a second optical path, the third waveguide core comprising silicon nitride (Si3N4) doped with the rare earth element; wherein the second waveguide core portion forms a polarization beam splitter rotator, the polarization beam splitter rotator being configured to separate the first polarization mode and the second polarization mode of the signal light, guide the first mode downward along the first waveguide core portion, and guide the second mode downward along the third waveguide core portion.

[0173] (34) An optical device comprising: a substrate; and a first waveguide core portion, the first waveguide core portion being formed on the substrate and comprising silicon nitride (Si3N4) doped with a rare earth element and disposed in a first vertical layer; a second waveguide core portion, the second waveguide core portion being formed on the substrate and comprising silicon nitride (Si3N4), disposed in a second vertical layer and optically coupled to the first core portion; and a cladding, the cladding being adjacent to the first core portion and the second core portion, wherein, under a condition that pump light and signal light pass through the first waveguide core portion, the first waveguide core portion amplifies the signal light.

[0174] (35) The optical device according to configuration 34, wherein the second waveguide core portion includes undoped silicon nitride (Si3N4).

[0175] (36) An optical device as described in configuration 35, wherein the second waveguide core portion includes a wavelength division multiplexing (WDM) coupler, the WDM coupler being configured to receive the pump light and the signal light and guide the pump light and the signal light into the first waveguide core portion, and wherein at least a portion of the WDM coupler is vertically stacked on at least a portion of the first waveguide core portion.

[0176] (37) An optical device as described in configuration 34, wherein the second waveguide core portion includes silicon nitride (Si3N4) doped with the rare earth element, and under the condition that the pump light and the signal light pass through the second waveguide core portion, the second waveguide core portion amplifies the signal light.

[0177] (38) The optical device according to Configuration 34, wherein the first waveguide core portion forms a first double helix, and the second waveguide core portion forms a second double helix vertically stacked on the first double helix.

[0178] (39) An optical device, comprising: a substrate; and a first waveguide, the first waveguide being formed on the substrate, the first waveguide comprising: a first core portion, the first core portion comprising silicon nitride (Si3N4) doped with a first rare earth element and disposed in a first vertical layer; a first cladding, the first cladding being adjacent to the first core portion, wherein, under a condition that pump light and signal light pass through the first core portion, the first core portion amplifies the signal light; and a second waveguide, the second waveguide being formed on the substrate, the second waveguide comprising: a second core portion, the second core portion comprising silicon nitride (Si3N4) doped with a second rare earth element and disposed in a second vertical layer; a second cladding, the second cladding being adjacent to the second core portion, wherein, under a condition that second pump light and second signal light pass through the second core portion, the second core portion amplifies the second signal light, wherein at least a portion of the first waveguide is vertically stacked on at least a portion of the second waveguide.

[0179] (40) The optical device as described in Configuration 39, wherein the first rare earth element is the same as the second rare earth element.

[0180] (41) The optical device according to configuration 39, wherein the first rare earth element is different from the second rare earth element.

[0181] (42) The optical device of configuration 41, wherein the first signal light is in one of the O-band and the C-band, and the second signal light is in the other of the O-band and the C-band.

[0182] It should be understood that both the general description and the detailed description provide examples that are illustrative in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. Various mechanical, compositional, structural, electronic and operational changes may be made without departing from the scope of the present specification and claims. In some instances, well-known circuits, structures and techniques are not shown or described in detail to avoid blurring these examples. In two or more drawings, the same number represents the same or similar element.

[0183] In addition, unless the context indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms as well. In addition, the terms "comprise", "include", "includes", etc. indicate the presence of the stated features, steps, operations, elements, and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or groups. Unless explicitly stated otherwise, the parts described as being coupled may be directly electrically or mechanically coupled, or may be indirectly coupled via one or more intermediate parts. Unless the context of the specification indicates otherwise, mathematical and geometric terms do not necessarily have to be used in accordance with their strict definitions, as one of ordinary skill in the art will understand that, for example, substantially similar elements that function in a substantially similar manner can easily fall within the scope of a descriptive term, even if the term also has a strict definition.

[0184] And / or: Occasionally, the phrase "and / or" is used herein in conjunction with a list of enumerated items. This phrase is meant to include any combination of the items in the list - from a single item to all items, and any permutations in between. Thus, for example, "A, B, and / or C" means one of "{A}, {B}, {C}, {A, B}, {A, C}, {C, B}, and {A, C, B}".

[0185] Elements and related aspects described in detail with reference to one example may be included in other examples where they are not specifically shown or described when feasible. For example, if an element is described in detail with reference to one example and is not described with reference to a second example, the element may still be claimed to be included in the second example.

[0186] In addition, unless otherwise stated herein or the context implies otherwise, when approximate terms such as "substantially," "approximately," "about," "around," "roughly," and the like are used, this should be understood to mean that mathematical precision is not required, but rather refers to a range of variation that includes but is not strictly limited to the stated value, characteristic, or relationship. In particular, in addition to any ranges (if any) explicitly recited herein, the range of variation implied by the use of such approximate terms includes at least any insignificant variations and those variations that are typical for items of the type in question due to manufacturing tolerances or other tolerances in the relevant art. In any case, unless otherwise indicated, the range of variation may at least include values ​​within the range of ±1% of the recited value, characteristic, or relationship.

[0187] In view of the disclosure of this article, many modifications and changes will be clear to those of ordinary skill in the art. For example, devices and methods may include additional components or steps omitted from the figures and descriptions for operational clarity. Accordingly, this description is only interpreted as illustrative and is to teach those skilled in the art the general way of performing this teaching. It should be understood that the various examples shown and described herein will be considered exemplary. Elements and materials, and the arrangement of these elements and materials can be used to replace those shown and described herein, parts and processes can be reversed, and certain features of this teaching can be independently utilized, all of which will be clear to those skilled in the art after benefiting from the description of this article. Without departing from the scope of this teaching and the appended claims, the elements described herein may be changed.

[0188] It is to be understood that the specific examples set forth herein are non-limiting and that modifications in structure, dimensions, materials, and methods may be made without departing from the scope of the present teachings.

[0189] Other examples from this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered exemplary only, and that the following claims be given their fullest breadth, including equivalents under applicable law.

Claims

1. An optical device, comprising: substrate; as well as A waveguide optical amplifier is formed on the substrate and comprises: a core defining an optical path through the waveguide optical amplifier; and A cladding is adjacent to at least one side of the core, wherein the core includes a silicon-based material doped with praseodymium (Pr), so that when pump light and O-band signal light pass through the waveguide optical amplifier, the waveguide optical amplifier amplifies the O-band signal light.

2. The optical device according to claim 1, in, The core includes silicon nitride (Si3N4), silicon-rich nitride, silicon oxide (SiO2), or silicon oxynitride (Si(x)O(y)N(z)); and in, The cladding layer includes nitride (Si3N4), silicon oxide (SiO2) or silicon oxynitride (Si(x)O(y)N(z)).

3. The optical device according to claim 1, in, The substrate is silicon or glass.

4. The optical device according to claim 1, in, The optical path defined by the core comprises a double helix.

5. The optical device according to claim 1, comprising: an input end located at a first edge of the optical device for optically coupling an input optical fiber to the core; as well as An output end is located at a second edge of the optical device for optically coupling an output optical fiber to the core, the second edge being different from the first edge.

6. The optical device according to claim 1, comprising: an input end located at a first edge of the optical device for optically coupling an input optical fiber to the core; as well as An output end is located at a first edge of the optical device adjacent to the input end for optically coupling an output optical fiber to the core.

7. The optical device according to claim 5, in, The optical path extends in a first direction at the input end and in a second direction at the output end, wherein the first direction is at an acute angle relative to the first edge and the second direction is at an acute angle relative to the second edge.

8. The optical device according to claim 1, comprising: A second waveguide optical amplifier is formed on the substrate and comprises: a second core defining a second optical path through the second waveguide optical amplifier, and a second cladding, wherein the second cladding is adjacent to at least one side of the second core, wherein the second core comprises a silicon-based material doped with praseodymium (Pr), so that when the pump light and the second O-band signal light pass through the second waveguide optical amplifier, the second waveguide optical amplifier amplifies the second O-band signal light.

9. The optical device according to claim 8, in, The waveguide optical amplifier and the second waveguide optical amplifier are adjacent to each other in the same vertical layer on the substrate or are interleaved with each other in the same vertical layer on the substrate.

10. The optical device according to claim 1, in, The waveguide optical amplifier comprises a second core defining a second optical path, wherein the optical device comprises a polarization beam splitter rotator configured to separate a first polarization mode and a second polarization mode of the signal light, rotate the first mode and direct the rotated first mode downward along the optical path, and direct the second mode downward along the second optical path; and Wherein, the optical device comprises a polarization rotator combiner configured to rotate the second mode and combine the rotated first mode with the rotated second mode.

11. The optical device according to claim 1, in, The cladding layer includes a silicon-based material, and the cladding layer includes a first region doped with a rare earth element and an undoped second region.

12. An optical device comprising: substrate; as well as a first waveguide core portion formed on the substrate and comprising a silicon-based material doped with a rare earth element; a second waveguide core portion formed on the substrate and comprising an undoped silicon-based material and optically coupled to the first core portion; a cladding adjoining the first waveguide core portion and the second waveguide core portion, Wherein, under the condition that pump light and signal light pass through the first waveguide core portion, the first waveguide core portion amplifies the signal light.

13. The optical device according to claim 12, in, The second waveguide core portion forms a wavelength division multiplexing (WDM) coupler configured to receive the pump light and the signal light and guide the pump light and the signal light into the first waveguide core portion.

14. The optical device according to claim 13, in, The second waveguide core portion includes a first segment and a second segment, the first segment is configured to receive the signal light, and the second segment is configured to receive the pump light, wherein the first segment is directly connected to the first core portion and the second segment is arranged to optically couple the pump light from the second segment into the first segment.

15. The optical device according to claim 12, in, The first waveguide core portion and the second waveguide core portion are arranged in a same vertical layer.

16. The optical device according to claim 12, in, The first waveguide core portion and the second waveguide core portion are arranged in different vertical layers.

17. The optical device according to claim 12, comprising: a third waveguide core portion comprising an undoped silicon-based material and optically coupled to the first waveguide core portion, wherein, in an optical path of the signal light passing through the optical device, the second waveguide core portion is located upstream of the first waveguide core portion, and the first waveguide core portion is located upstream of the third waveguide core portion.

18. The optical device according to claim 17, comprising: a fourth waveguide core portion, the fourth waveguide core portion comprising a silicon-based material doped with a second rare earth element; a fifth waveguide core portion comprising an undoped silicon-based material and optically coupled to the fourth waveguide core portion; wherein the cladding adjoins the fourth waveguide core portion and the fifth waveguide core portion, Wherein, under the condition that the second pump light and the second signal light pass through the fourth waveguide core portion, the fourth waveguide core portion amplifies the second signal light.

19. The optical device according to claim 18, in, The first waveguide core portion and the fourth waveguide core portion are adjacent to each other in the same vertical layer on the substrate or are staggered with each other in the same vertical layer on the substrate.

20. The optical device according to claim 18, in, The first waveguide core portion and the fourth waveguide core portion are vertically stacked in different vertical layers on the substrate.

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