Optics for coarse wavelength division multiplexed bands

Abstract

Optical devices for coarse wavelength division multiplexing bands and systems and methods for achieving modest bandwidth expansion (i.e., higher data transmission rates) for coarse wavelength division multiplexing (CWDM) and CWDM-4 technology are provided. Examples leverage a band architecture built around the CWDM wavelengths. This band architecture adds additional wavelength transmission lanes (which can equate to faster data transmission rates) while maintaining backward compatibility with existing CWDM / CWDM-4 technology. Examples can include band devices (e.g., band light sources, band transmitters, band receivers, band transceivers, etc.) designed to operate in one or more CWDM bands while maintaining backward compatibility with existing CWDM-4 technology.

Description

BACKGROUND

[0001] Wavelength Division Multiplexing (WDM) can refer to a technology that combines multiple optical signals of different wavelengths onto a common optical fiber. These optical signals can be transmitted simultaneously on the optical fiber via separate wavelength transmission channels (for conceptual illustration, these wavelength transmission channels can be viewed as separate lanes on a highway for different colors of light, e.g., a lane / transmission channel for green light, a lane / transmission channel for blue light, etc.). There are two traditional WDM methods: Coarse Wavelength Division Multiplexing (CWDM) and Dense Wavelength Division Multiplexing (DWDM).

[0002] CWDM uses wider wavelength transmission channel spacing than DWDM. For example, certain CWDM technologies can space wavelength transmission channels approximately 20 nanometers (nm) apart on the electromagnetic spectrum. These wavelengths can be referred to as CWDM wavelengths.

[0003] CWDM-4 is an industry standard that aims to provide a common specification for optical interconnects (such as pluggable optical transceiver modules) for various applications (such as data centers). The CWDM-4 standard uses four CWDM wavelengths: approximately 1271 nm, 1291 nm, 1311 nm, and 1331 nm. These four wavelengths can be referred to as CWDM-4 wavelengths.

[0004] In contrast to CWDM, DWDM generally uses a larger number of wavelength transmission channels per optical fiber. DWDM can accommodate these additional channels by packing the channels more densely than CWDM. For example, DWDM wavelengths can be spaced approximately 0.4 nm or 0.8 nm apart (i.e., approximately 25 to 50 times closer than CWDM). BRIEF DESCRIPTION OF DRAWINGS

[0005] The present disclosure is described in detail according to one or more various examples in connection with the accompanying drawings. The drawings are provided for purposes of illustration only and merely depict typical or exemplary examples.

[0006] Figure 1 is an example diagram illustrating a coarse wavelength division multiplexing band architecture in accordance with various examples of the technology of this disclosure.

[0007] Figure 2 depicts an example band light source in accordance with various examples of the technology of this disclosure.

[0008] Figure 3 depicts another example band light source in accordance with various examples of the technology of this disclosure.

[0009] Figure 4 depicts another example band light source in accordance with various examples of the technology of this disclosure.

[0010] Figure 5Another example waveband light source depicting various examples of the techniques of this disclosure.

[0011] Figure 6 Another example waveband light source depicting various examples of the techniques of this disclosure.

[0012] Figure 7 Another example waveband light source depicting various examples of the techniques of this disclosure.

[0013] Figure 8 An example waveband transmitter depicting various examples of the techniques of this disclosure.

[0014] Figure 9 Another example waveband transmitter depicting various examples of the techniques of this disclosure.

[0015] Figure 10 Another example waveband transmitter depicting various examples of the techniques of this disclosure.

[0016] Figure 11 Another example waveband transmitter depicting various examples of the techniques of this disclosure.

[0017] Figure 12 Another example waveband transmitter depicting various examples of the techniques of this disclosure.

[0018] Figure 13 An example waveband receiver depicting various examples of the techniques of this disclosure.

[0019] Figure 14 Another example waveband receiver depicting various examples of the techniques of this disclosure.

[0020] Figure 15 Another example waveband receiver depicting various examples of the techniques of this disclosure.

[0021] The accompanying drawings are not exclusively exhaustive, and do not limit the disclosure to the precise form disclosed. DETAILED DESCRIPTION

[0022] Optical interconnects (e.g., devices that use light to transmit signals from one location to another) are often used in high-performance computer networks because they can achieve high bandwidth over long distances at lower power than electrical interconnects.

[0023] Pluggable optical transceiver modules are components in optical interconnects that can contain a coherent light source (e.g., a laser), an optical data transmitter (an optical device capable of transmitting data into an optical signal by modulating the optical signal), and an optical receiver (an optical device capable of detecting a modulated optical signal) in the same physical package. Many of these pluggable optical transceiver modules are designed to operate in the CWDM-4 standard. Specifically, they are designed to generate, modulate, and detect one single wavelength (within a certain tolerance) per CDWM-4 passband (as used herein, a CWDM or CWDM-4 passband can refer to a spectrum of wavelengths that includes the CWDM / CWDM-4 wavelengths, which can be passed through an optical filter). In certain technical fields, such as data centers, CWDM-4 pluggable optical transceiver modules are commonly used. With industry standard 100 gigabit (G) serializer / deserializers (SERDES), these CDWM-4 modules can achieve data transfer rates of approximately 400 gigabits per second (Gbps) per optical fiber (i.e., 100G x 4 wavelength transmission lanes).

[0024] However, future networks are expected to require higher data transfer rates (e.g., 800 Gbps). Unfortunately, CWDM-4 pluggable optical transceiver modules (and other CWDM-4 devices) are unable to achieve these higher rates under the 100G SERDES standard.

[0025] One method of increasing the transfer rate under the current 100G SERDES standard would be to increase the number of wavelength transmission lanes per optical fiber (as the data transfer rate per optical fiber is approximately proportional to the number of transmission lanes per optical fiber). Accordingly, certain industries (e.g., the telecommunications industry) have moved to dense wavelength division multiplexing (DWDM). As mentioned above, DWDM can accommodate a large number of wavelength transmission lanes per optical fiber by packing the transmission lanes more densely than CWDM.

[0026] However, moving to DWDM comes at a cost. Because the wavelength transmission lanes of DWDM are packed more densely, DWDM devices (e.g., light sources / lasers) must be more precise and, therefore, more expensive. Additionally, in certain applications, such as data centers, the channel spacing of DWDM can be too close. This is because when data is transmitted into an optical signal, the spectrum of the optical signal becomes wider. In applications such as data centers, where large data packets (i.e., “large data payloads”) are transmitted into the optical signal, the widened optical signal can overlap / interfere as it travels along the densely packed transmission lanes, resulting in crosstalk and higher bit error rates.

[0027] In this context, examples of the technology of the present disclosure enable modest bandwidth expansion (i.e., higher data transmission rates) by utilizing a waveband architecture built around CWDM wavelengths. This waveband architecture adds additional wavelength transmission lanes (as noted above, additional transmission lanes can equate to higher data transmission rates) while maintaining backward compatibility with existing CWDM / CWDM-4 technology (e.g., CWDM-4 pluggable optical transceiver modules).

[0028] According to various examples, a CWDM waveband architecture can include one or more CWDM wavebands. A CWDM waveband can refer to two or more wavelengths within a CWDM passband. As noted above, a CWDM passband can refer to a spectrum of wavelengths that includes one CWDM wavelength that can pass through an optical filter.

[0029] Accordingly, examples of the technology of the present disclosure can include waveband devices (e.g., waveband light sources, waveband transmitters, waveband receivers, waveband transceivers, etc.) that are designed to operate one or more CWDM wavebands while maintaining backward compatibility with existing CWDM-4 technology. These waveband devices can be constructed using off-the-shelf building blocks used by existing CWDM-4 technology.

[0030] For example, utilizing the CWDM band concept of the present disclosure and building blocks found in silicon photonics and III-V foundry process design kits (e.g., CWDM-4 distributed feedback lasers, wideband fiber-to-chip couplers, CWDM-4 optical filters, etc.), a "band light source" can be constructed to operate in two modes. In a first mode, the band light source can produce one single wavelength per CWDM-4 passband (consistent / compliant with existing CWDM-4 technology). In a second mode, the band light source can produce multiple wavelengths per CWDM-4 passband (i.e., a CWDM band). To illustrate the concept, the band light source can be constructed using eight CWDM-4 distributed feedback lasers. Two of the lasers can be calibrated to produce light within a first CWDM-4 passband (the first CWDM-4 passband can include a spectrum of wavelengths between, for example, 1264.5 nm and 1277.5 nm). The two lasers can be calibrated to produce different optical wavelengths within the first CWDM-4 passband (e.g., 1268.5 nm and 1273.5 nm, respectively). In the same / similar manner: two lasers can be calibrated to produce optical wavelengths within a second CWDM-4 passband (e.g., 1284.5 nm to 1297.5 nm); two lasers can be calibrated to produce optical wavelengths within a third CWDM-4 passband (e.g., 1304.5 nm to 1317.5 nm); and two lasers can be calibrated to produce optical wavelengths within a fourth CWDM-4 passband (e.g., 1324.5 nm to 1337.5 nm). When the band light source is operated in the first mode, one laser per band / passband can be turned off. Thus, the band light source can operate seamlessly with existing CWDM-4 technology, which is designed to operate with one single wavelength per CWDM-4 passband (within certain tolerance values). When the band light source is operated in the second mode, all eight lasers can be turned on. Thus, the band light source can produce eight optical wavelengths within the four CWDM-4 passbands, thereby doubling the number of wavelength transmission channels used by existing CWDM-4 technology. When used in combination with a band transmitter and a band receiver designed to operate with the eight wavelengths, the band light source can facilitate a data transmission rate of approximately 800 Gbps when utilizing 100G SERDES (i.e., 100G x 8 wavelength transmission channels).

[0031] In certain examples, a waveband transmitter can be constructed using building blocks found in silicon photonics and III-V foundry process design kits (e.g., high-speed Mach Zehnder or micro-ring modulators, wideband fiber-to-chip couplers, etc.). Such a waveband transmitter can be capable of modulating (1) a single wavelength per CWDM-4 passband (which would be compatible with existing CWDM-4 technology), and (2) two or more wavelengths per CWDM-4 passband. To illustrate the concept, a waveband transmitter can be constructed using eight optical modulators. Two of the optical modulators can be calibrated to modulate light within a first CWDM-4 passband (e.g., 1264.5 nm to 1277.5 nm). These two optical modulators can be calibrated to modulate different optical wavelengths within the first CWDM-4 passband (e.g., 1268.5 nm and 1273.5 nm, respectively). In the same / similar manner: two optical modulators can be calibrated to modulate optical wavelengths within a second CWDM-4 passband (e.g., 1284.5 nm to 1297.5 nm); two optical modulators can be calibrated to modulate optical wavelengths within a third CWDM-4 passband (e.g., 1304.5 nm to 1317.5 nm); and two optical modulators can be calibrated to modulate optical wavelengths within a fourth CWDM-4 passband (e.g., 1324.5 nm to 1337.5 nm). Thus, this waveband transmitter can operate seamlessly with existing CWDM-4 optical sources and optical receivers (here, four of the eight optical modulators would be used). The waveband transmitter can also be used in combination with waveband optical sources and waveband receivers that operate using CWDM-4 wavebands (here, all eight optical modulators can be used). As noted above, when utilizing 100G SERDES, the combination of waveband devices can achieve a data transmission rate of approximately 800 Gbps (i.e., 100G x 8 wavelength transmission lanes).

[0032] In some examples, a waveband receiver can be constructed using building blocks found in silicon photonics and III-V foundry process design suites (e.g., a monitor or high-speed waveguide photodetector, a broadband fiber-to-chip coupler, etc.). This waveband receiver can be capable of detecting (1) a single modulated wavelength per CWDM-4 passband (the wavelength will be compatible with existing CWDM-4 technology), and (2) two or more modulated wavelengths per CWDM-4 passband. To illustrate the concept, a waveband receiver can be constructed using eight waveguide photodetectors. Two of the waveguide photodetectors can be calibrated to detect modulated light within a first CWDM-4 passband (e.g., 1264.5 nm to 1277.5 nm). These two waveguide photodetectors can be calibrated to detect different modulated wavelengths of light within the first CWDM-4 passband (e.g., 1268.5 nm and 1273.5 nm, respectively). In the same / similar manner: two waveguide photodetectors can be calibrated to detect modulated light wavelengths within a second CWDM-4 passband (e.g., 1284.5 nm to 1297.5 nm); two waveguide photodetectors can be calibrated to detect modulated light wavelengths within a third CWDM-4 passband (e.g., 1304.5 nm to 1317.5 nm); and two waveguide photodetectors can be calibrated to detect modulated light wavelengths within a fourth CWDM-4 passband (e.g., 1324.5 nm to 1337.5 nm). Thus, this waveband receiver can operate seamlessly with existing CWDM-4 light sources and optical data transmitters (here, four of the eight waveguide photodetectors will be used). The waveband receiver can also be used in combination with waveband light sources and waveband transmitters that operate using the CWDM-4 waveband (all eight waveguide photodetectors can be used here). As noted above, the combination of waveband devices can achieve a data transmission rate of approximately 800 Gbps when utilizing industry standard 100G SERDES (i.e., 100G x 8 wavelength transmission lanes).

[0033] In various examples, the waveband light source, waveband transmitter, and waveband receiver can be incorporated into a single physical structure (e.g., a pluggable waveband transceiver module and an electrical integrated circuit package). As noted above, the pluggable waveband transceiver module and the electrical integrated circuit package can be constructed using building blocks used to construct existing CWDM-4 pluggable optical transceiver modules.

[0034] Examples of the technology of the present disclosure provide a number of advantages over existing CWDM and DWDM technologies. For example, the band optical devices, transmitters, and receivers can be constructed using off-the-shelf building blocks used to construct existing CWDM-4 technology. In many cases, these building blocks are less expensive than the building blocks used to construct DWDM technology. Another advantage of the technology of the present disclosure is that the technology provides a modest bandwidth expansion option to technology sectors / industries that require wider wavelength transmission channel spacing than allowed by DWDM. For example, for large data payload applications such as data centers, it can not be feasible to utilize DWDM (because the sub-nanometer channel spacing of DWDM can be too tight for large data payloads / wider optical signals). However, band optical devices can be constructed to operate with, for example, two wavelength transmission channels per CWDM-4 passband. These wavelength transmission channels can be spaced apart by approximately 4-5 nm (as opposed to the 0.4 nm or 0.8 nm channel spacing of DWDM). Thus, the data transmission rate can be doubled while maintaining a wide enough wavelength transmission channel spacing for larger data payload applications. A third advantage of the technology of the present disclosure is that the technology is backward compatible with existing CWDM / CWDM-4 technology. While backward compatibility is generally advantageous for new technology, it is particularly so in this technical field because CWDM-4 equipment is widely used. Thus, for technology sectors / industries that have come to rely heavily on CWDM-4 equipment, band optical devices that facilitate 800 Gbps (or higher) data transmission rates while maintaining interoperability with legacy CWDM-4 equipment can be highly desirable.

[0035] Figure 1 FIG. 1 illustrates an example diagram of a CWDM band architecture in accordance with various examples of the technology of the present disclosure. As depicted, the CWDM band architecture 100 includes four bands. However, in other examples, the CWDM band architecture can include one or more bands. As described above, a CWDM band can refer to two or more wavelengths within a CWDM passband. A CWDM passband can refer to a spectrum of wavelengths that includes CWDM wavelengths that are capable of passing through an optical filter. A CWDM wavelength can refer to a set of wavelengths that are spaced apart by approximately 20 nm on the electromagnetic spectrum. In some cases, the CWDM passband can be a spectrum of wavelengths that includes CWDM-4 wavelengths. A CWDM-4 wavelength can be one of four wavelengths that are between approximately 1271 nm and 1331 nm and spaced apart by approximately 20 nm on the electromagnetic spectrum (e.g., 1271 nm, 1291 nm, 1311 nm, 1331 nm).

[0036] As depicted, the CWDM band 110 includes two wavelengths spaced apart by approximately 4.3 nm: wavelength 110a and 110b. In other examples, the CWDM band 110 can include any number of wavelengths spaced apart by various lengths. However, in certain applications involving large data payloads, it can be preferable to limit the band to 16 or fewer wavelengths. This is because as data is transmitted to an optical signal, the optical signal becomes“wider.” Thus, as the wavelength transmission lanes are more densely packed, the wider optical signal can begin to overlap / interfere, resulting in crosstalk and bit errors in the data transmission.

[0037] The CWDM passband of the CWDM band 110 is centered at a first CWDM-4 wavelength of approximately 1271 nm and is approximately 13 nm wide. In other examples, the CWDM passband can have a different width (depending on the optical filters used) and need not be centered at a CWDM-4 wavelength.

[0038] The CWDM bands 120, 130, and 140 also include two wavelengths. Similar to the CWDM passband of the CWDM band 110, the CWDM passband of the CWDM bands 120, 130, and 140 are each centered at one wavelength of a CWDM-4. As described above, band architectures like the CWDM band 110 increase the number of wavelength transmission lanes for CWDM-based technology. Specifically, optical devices designed to operate with the band architecture 100 can utilize eight wavelength transmission lanes (two wavelength transmission lanes per CWDM band / passband). This is twice the number of wavelength transmission lanes used by existing CWDM-4 technology. As described above, by doubling the number of wavelength transmission lanes, examples of the present technology can double the data transmission rate. For conceptual purposes, if each of the depicted CWDM bands included three wavelengths instead of two wavelengths, the data transmission rate could be three times the data transmission rate of existing CWDM-4 technology. However, optical devices designed to operate with three wavelengths per CWDM band (versus two wavelengths) can require additional components / hardware (e.g., additional lasers, additional optical modulators, additional photodetectors, etc.), which can increase the cost of fabrication, operation, etc. Additionally, the narrower lane spacing required to provide three wavelengths per CWDM band can not be preferable / optimal for certain applications.

[0039] Figure 2 An example band light source is depicted that is in accordance with various examples of the technology of the present disclosure. The band light source 200 includes four laser arrays, a star coupler, eight input waveguides connecting the laser arrays to the star coupler, and eight output waveguides from the star coupler.

[0040] The laser arrays 210, 212, 214, and 216 can be any laser array capable of producing two or more optical wavelengths within the CWDM passband. As used herein, a laser array can refer to an arrangement of two or more lasers on a single physical structure such as a silicon chip. As depicted, each of the laser arrays includes two lasers, but in other examples, the laser arrays can include additional lasers. In various examples, these laser arrays can be constructed using off-the-shelf CWDM-4 distributed feedback lasers found in silicon photonics and III-V foundry process design kits.

[0041] Each laser in the laser array can produce coherent light at a particular wavelength within the CWDM passband. For example, the laser 210a can produce a first optical wavelength within the first CWDM passband, and the laser 210b can produce a second optical wavelength within the first CWDM passband (in practice, these wavelengths can shift slightly based on operating temperature, but the wavelengths will generally shift in the same direction and by the same amount, ensuring that the wavelength transmission channel spacing is maintained). Thus, the two wavelengths produced by the laser array 210 can be referred to as a first CWDM band. In the same / similar manner as the lasers 210a and 210b, the lasers 212a / 212b, 214a / 214b, and 216a / 216b can produce different coherent optical wavelengths within the second, third, and fourth CWDM passbands, respectively. Thus, the wavelengths produced by the laser arrays 212, 214, and 216 can be referred to as second, third, and fourth CWDM bands, respectively. In various embodiments, these four CWDM passbands / bands can be CWDM-4 passbands / bands.

[0042] In summary, each laser array in the band light source 200 can produce its own CWDM band. These four CWDM bands can include eight different wavelengths (i.e., eight wavelength transmission channels). Thus, the band light source 200 can simultaneously produce eight optical signals that can be carried on these eight different wavelength transmission channels. These optical signals are denoted as λ 11 , λ 12 , λ 21 , λ 22 , λ 31 , λ 32 , λ 41 , and λ 42 Here, the wavelengths of the optical signals λ 11 and λ 12 make up a first band; the wavelengths of the optical signals λ 21 and λ 22 make up a second band; the wavelengths of the optical signals λ 31 and λ 32 make up a third band; and the wavelengths of the optical signals λ 41 and λ42 The wavelengths constitute the fourth band. These eight optical signals can be collectively referred to as optical signal λ. 11 To λ 42 Or “input optical signal”.

[0043] In some examples, the light signal λ 11 To λ 42 Optical filters (not depicted) can be used. As mentioned above, these optical filters can determine / define the wavelength spectrum included in the CWDM passband of a given CWDM band. In other words, the CWDM passband of a given CWDM band can refer to the wavelength spectrum that can be transmitted through the optical filter without attenuation. In various examples, the optical filters used in conjunction with the band light source 200 can be off-the-shelf optical filters used in existing CWDM-4 technology.

[0044] After passing through the optical filter, the optical signal λ 11 To λ 42 Transmission can be made to star coupler 220 via a single waveguide (i.e., the input waveguide to star coupler 220). These waveguides can be constructed using off-the-shelf optical components (e.g., fiber-to-chip couplers, optical waveguides, etc.) found in silicon photonics factory process design kits.

[0045] The star coupler 220 can be any device (or combination of devices) that takes a given input signal and splits the signal into multiple output signals. For example, combining... Figures 3 to 5 In more detail, this star coupler 220 may be a single multimode interferometer (MMI) or a combination of MMIs (e.g., cascaded MMIs). As used herein, an MMI may refer to a microscale structure that splits or combines optical signals (and their corresponding powers) in a predictable manner.

[0046] The star coupler 220 can split each input optical signal into eight output optical signals. For example, the star coupler 220 can split the optical signal λ 11 It splits into eight output optical signals: λ 11(a) , λ 11(b) , λ 11(c) , λ 11(d) , λ 11(e) , λ 11(f) , λ 11(g) , λ 11(h) (These optical signals can be referred to as optical signals λ) 11(a-h) , or "input optical signal λ 11 The output optical signal (λ). As described, the optical signal λ 11(a-h) Each optical signal can be transmitted from the star coupler 220 to one of the eight output waveguides. In transmitting the optical signal λ... 11When split into eight output optical signals, the star coupler 220 splits the optical power of λ 11 into eight parts. In other words, the power split ratio between the input optical signal λ 11 and each of the output signals associated therewith is 1 :8. The optical signals λ 12 through λ 42 can be split in the same / similar manner as the optical signal λ 11 .

[0047] In addition to splitting each of the input optical signals into eight output optical signals, the star coupler 220 can also combine (i.e., multiplex) optical signals onto a common output waveguide. For example, the star coupler 220 can combine the output optical signals λ 11(a) , λ 12(a) , λ 21(a) , λ 22(a) , λ 31(a) , λ 32(a) , λ 41(a) , and λ 42(a) onto a first output waveguide. In the same / similar manner, the star coupler 220 can: combine the output optical signals λ 11(b) , λ 12(b) , λ 21(b) , λ 22(b) , λ 31(b) , λ 32(b) , λ 41(b) , and λ 42(b) onto a second output waveguide; combine the output optical signals λ 11(c) , λ 12(c) , λ 21(c) , λ 22(c) , λ 31(c) , λ 32(c) , λ 41(c) , and λ 42(c) onto a third output waveguide; and so on. As noted above, each of these output optical signals can be a power-reduced version of one of the input optical signals. For example: the output optical signals λ 11(a) , λ 11(b) , and λ 11(c) are power-reduced versions of the input optical signal λ 11 ; the output optical signals λ 12(a) , λ 12(b) , and λ 12(c) are power-reduced versions of the input optical signal λ 12 ; the output optical signals λ 21(a) , λ 21(b) , and λ 21(c) are power-reduced versions of the input optical signal λ 21power-reduced versions of the eight input optical signals. Thus, each of the eight waveguides exiting the star coupler 220 can receive / transmit a power-reduced version of each of the eight input optical signals.

[0048] In summary, the star coupler 220 can (1) split each of the input optical signals into eight power-reduced output optical signals; and (2) combine the power-reduced output optical signals corresponding to each of the input optical signals onto a common waveguide. Thus, each of the eight waveguides exiting the star coupler 220 can receive / transmit a single optical beam comprising eight output optical signals. Each of the eight output optical signals can be a power-reduced version of one of the input optical signals (i.e., optical signals λ 12 through λ 42 ). As will be described in greater detail below, each of the eight output waveguides can be connected to a separate waveband transmitter. A given waveband transmitter can modulate the eight (different wavelength) optical signals it receives. Thus, the total output signal from the eight waveband transmitters can be 64 modulated optical signals (i.e., eight waveband transmitters x eight optical signals per waveband transmitter). As noted above, the modulated optical signals can comprise imparting data to the signals. Thus, the four laser arrays of the waveband light source 200 can be used to simultaneously produce 64 optical signals capable of carrying data. This ratio of 16: 1 between the number of produced optical signals and the number of laser arrays can be extremely attractive to certain customers.

[0049] As noted above, the waveband light source 200 can operate in two modes. In a first mode, the waveband light source 200 can be backward compatible with existing CWDM-4 technology. In particular, one laser of each laser array can be turned off (or blocked, etc.) so that each laser array produces only a single wavelength of optical signal per CWDM-4 passband. Thus, in this first mode, the four laser arrays of the waveband light source 200 can be used to simultaneously produce / transmit 32 optical signals capable of carrying data (i.e., four input optical signals split into eight different output waveguides). In contrast, in a second mode, all of the lasers can be "turned on" (e.g., can be unblocked, etc.). Thus, the waveband light source 200 can be used to simultaneously produce / transmit 64 optical signals capable of carrying data.

[0050] Figure 3 Another example waveband light source is depicted that illustrates various examples in accordance with the techniques of this disclosure. The waveband light source 300 includes four laser arrays, an 8x8 multimode interferometric device (MMI), eight input waveguides connecting the laser arrays to the 8x8 MMI, and eight output waveguides from the 8x8 MMI.

[0051] Figure 3 may be used in conjunction withFigure 2 identical / similar to Figure 2 The generic star coupler of Figure 2 has been replaced by an 8x8 MMI 320. As mentioned above, an MMI can refer to a microscale structure that splits or combines optical signals (and their powers) in a predictable manner. Similar to the star coupler 220 of , the 8x8 MMI 320 has eight inputs as well as eight outputs (hence the 8x8 prefix), and combines a power-reduced version of each of the input optical signals (i.e., the optical signals 11 to 42 ) it receives onto eight different output waveguides. Thus, similar to the waveband light source 200, the waveband light source 300 can produce / emits 64 optical signals that can carry data.

[0052] Figure 4 depicts another example waveband light source in accordance with various examples of the technology of this disclosure. The waveband light source 400 includes four laser arrays, four 2x2 MMIs, two 4x4 MMIs, and various waveguides connecting the aforementioned components.

[0053] Here, the combination of six MMIs that make up the waveband light source 400 operate in the same / similar manner as the star coupler 220 of Figure 2 and the 8x8 MMI 320 of Figure 3 . In particular, the combination of MMIs (which can be referred to as a cascaded MMI) combines a power-reduced version of each of the input optical signals produced by the laser arrays 410, 412, 414, and 416 onto eight different output waveguides that exit the two 4x4 MMIs. In other words, each of the eight final output waveguides of the cascaded MMI combination can receive / emits a single optical beam that includes eight output optical signals, where each of the eight output optical signals is a power-reduced version of one of the input optical signals to . Thus, similar to the waveband light sources 200 and 300, the waveband light source 400 can produce 64 optical signals that can carry data.

[0054] In various examples, Figure 4 the cascaded MMI architecture of Figure 3 may be superior to the single 8x8 MMI architecture of Figure 4 because the cascaded MMI architecture of may have a smaller / shorter physical profile.

[0055] Figure 5 depicts another example waveband light source in accordance with various examples of the technology of this disclosure. The waveband light source 500 includes four laser arrays, four microring resonators, a 4x4 MMI, and various waveguides.

[0056] A microring resonator can refer to a closed loop waveguide that couples an input waveguide to an output waveguide. Here, a given microring resonator couples a waveguide carrying an optical signal produced by a first laser in the laser array to a waveguide carrying an optical signal produced by a second laser in the laser array. In other words, the microring resonator couples waveguides of a common waveband. Like the other components described above, these microring resonators can be constructed / obtained from an off-the-shelf silicon photonics foundry process design kit, or custom designed based on the kit.

[0057] In the example of waveband light source 500, four microring resonators can act as demultiplexers for optical signals of a certain wavelength. For example, microring resonator 520 can be tuned to "demultiplex" the wavelength of the optical signal produced by laser 510a (e.g., optical signal π 11 ). Microring resonator 520 can also be tuned to allow other wavelengths of optical signals to pass through unimpeded. Thus, microring resonator 520 can "demultiplex" optical signal π 11 onto a waveguide carrying optical signal π 12 , while allowing optical signal π 12 to pass through unimpeded. These two optical signals (which, as described above, can comprise a first CWDM waveband) can then be carried on a common waveguide to 4x4 MMI 530. Microring resonators 522, 524, and 526 can be tuned in the same / similar manner. Thus, 4x4 MMI 530 can have four input waveguides. As described above, each of the waveguides entering 4x4 MMI 530 can carry optical signals of a common CWDM waveband.

[0058] 4x4 MMI 530 has four input waveguides as well as four output waveguides (hence the 4x4 prefix). Thus, 4x4 MMI 530 functions somewhat differently than the star coupler 220, the cascade MMI combination of 8x8 MMI 320 and Figure 4 . In particular, 4x4 MMI 530 combines power-reduced versions of the input optical signals produced by laser arrays 510, 512, 514, and 516 onto four different output waveguides. In other words, each of the input optical signals π 11 through π 42 is only split into four output signals (whereas in the star coupler 220, each input optical signal was split into eight output signals). Figures 2 to 4In each of the waveband light sources 200, 300, and 400, each input signal is split into eight output signals. Because each input signal is only split into four output signals, the power split ratio between the input signal and the output signals is only 1 :4. In applications that require higher power optical signals in the detection phase, this low power split ratio can be preferable. Unlike the waveband light sources 200, 300, and 400, which can produce / emits 64 optical signals, the waveband light source 500 can only produce 32 optical signals that can carry data. Thus, a light source like the waveband light source 500 can trade-off data transmission density to maintain higher power optical signals.

[0059] Figure 6 Another example waveband light source is depicted that is in accordance with various examples of the technology of this disclosure. The waveband light source 600 includes four laser arrays, two multiplexers (MUXs), a micro-ring interleaver MUX, and various waveguides that connect the aforementioned components.

[0060] As depicted, the laser array 610 can produce optical signals of a first waveband. In particular, the laser 610a can produce optical signals of a first wavelength of the first waveband (e.g., optical signal φ 11 ), and the laser 610b can produce optical signals of a second wavelength of the first waveband (e.g., optical signal φ 12 ). Here, the optical signals of the first wavelength of the first waveband (e.g., optical signal φ 11 ) can be carried to the MUX 620, and the optical signals of the second wavelength of the first waveband (e.g., optical signal φ 12 ) can be carried to the MUX 622. In the same / similar manner, the optical signals of a first wavelength of a second waveband (e.g., optical signal φ 21 ) can be carried to the MUX 620, and the optical signals of a second wavelength of the second waveband (e.g., optical signal φ 22 ) can be carried to the MUX 622. In the same / similar manner, the optical signals of a first wavelength of a third waveband (e.g., optical signal φ 31 ) can be carried to the MUX 620, and the optical signals of a second wavelength of the third waveband (e.g., optical signal φ 32 ) can be carried to the MUX 622. In the same / similar manner, the optical signals of a first wavelength of a fourth waveband (e.g., optical signal φ 41 ) can be carried to the MUX 620, and the optical signals of a second wavelength of the second waveband (e.g., optical signal φ 42 ) can be carried to the MUX 622. In sum, the MUX 620 can receive optical signals of a first wavelength of a CWDM waveband (which can be referred to as “odd optical signals”), and the MUX 622 can receive optical signals of a second wavelength of the CWDM waveband (which can be referred to as “even optical signals”).

[0061] As described above, a multiplexer (or MUX) can refer to an optical device that combines multiple optical signals of different wavelengths onto a common optical fiber / waveguide (in other words, an MUX can combine optical signals of different wavelengths into a common beam that can be transmitted along a single waveguide). Therefore, MUXs 620 and 622 can combine the different wavelength optical signals they receive onto a common waveguide. Specifically, MUX 620 can combine odd-numbered optical signals (e.g., optical signal φ) onto a common waveguide. 11 φ 21 φ 31 φ 41 The MUX 622 can combine even-numbered optical signals (e.g., optical signal φ) onto the first common waveguide. 12 φ 22 φ 32 φ 42 The signals are combined onto the second common waveguide. Here, since no optical signal is split by MUX 620 and 622, the power of the optical signal output from the MUX is not reduced. In other words, the power splitting ratio of MUX 620 and 622 is 1:1.

[0062] MUX 620 and MUX 622 can be different types of MUXs. In some embodiments, MUX 620 and MUX 622 can be lattice filter MUXs or arrayed waveguide grating (AWG) MUXs that can be constructed / obtained / designed from off-the-shelf silicon photonics factory process design kits.

[0063] The waveguides exiting MUX 620 and MUX 622 each lead to a micro-loop interleaver (MUX 630). A micro-loop interleaver (MUX) can be an optical device that combines even-numbered multiplexed optical signals with odd-numbered multiplexed optical signals onto a common fiber / waveguide. Similar to... Figure 5 The microring resonator, the microring interleaver MUX 630, can act as a filter for optical signals of certain wavelengths. Specifically, the microring interleaver MUX 630 can be tuned to filter odd-numbered optical signals (e.g., optical signal φ). 11 φ 21 φ 31 φ 41 The signal is "distributed" to the waveguide carrying an even number of optical signals, while allowing an even number of optical signals (e.g., optical signal φ) to be distributed. 12 φ 22 φ 32 φ 42 The micro-loop interleaver MUX 630 can transmit odd-numbered and even-numbered optical signals (e.g., optical signal φ) without interference. 11 To φ 42 They are combined onto a single output waveguide.

[0064] In certain examples, the micro-ring interleaver MUX 630 can have a free spectral range (FSR) that is periodic. This FSR can allow the micro-ring interleaver MUX 630 to "split" an optical signal of wavelengths spaced apart by some interval. For example, the lasers 610a, 612a, 614a, and 616a can be calibrated to produce "odd" wavelengths of light that are spaced apart by approximately 20 nm. Thus, the FSR of the micro-ring interleaver MUX 630 can be tuned to "split" the optical signal of these odd, periodically spaced wavelengths. In certain embodiments, the interleaver MUX can be constructed from one or more micro-rings, Mach-Zehnder interferometers, or the like.

[0065] Figure 7 Another example band light source is depicted that is in accordance with various examples of the technology of this disclosure. The band light source 700 can be viewed as a generic band light source from which the band light sources 200-600 can be derived.

[0066] The band light source 700 includes at least a first laser array (laser array 710), although the band light source 700 can include any number of laser arrays. For example, the band light source 700 can also include a second laser array (e.g., laser array 712), a third laser array (e.g., laser array 714), and a fourth laser array (e.g., laser array 716).

[0067] The laser array 710 can be any laser array that emits optical signals of at least a first wavelength and a second wavelength within a first CWDM passband. As described above, the first CWDM passband can refer to a spectrum of wavelengths that includes CWDM wavelengths that can pass through an optical filter. In certain examples, the first CWDM passband can include CWDM-4 wavelengths. In some of these examples, the first CWDM passband can include a first CWDM-4 wavelength (i.e., approximately 1271 nm).

[0068] The laser array 710 can refer to an arrangement of two or more lasers on a single physical structure such as a silicon or InP chip. Thus, a first laser (e.g., laser 710a) in the laser array 710 can emit an optical signal of a first wavelength within the first CWDM passband. A second laser (e.g., laser 710b) in the laser array 710 can emit an optical signal of a second wavelength within the first CWDM passband. In certain examples, the laser array 710 can include additional lasers that emit, for example, an optical signal of a third wavelength within the first CWDM passband; an optical signal of a fourth wavelength within the first CWDM passband; etc. In various examples, the laser array 710 can be constructed using off-the-shelf CWDM-4 distributed feedback lasers found in a silicon photonics foundry process design kit.

[0069] As described above, the waveband light source 700 can have a first mode and a second mode. In the first mode, the laser array 710 can emit only light signals of a first wavelength within a first CWDM passband (e.g., laser 710b can be turned off, blocked, etc.). Thus, when in this first mode, the waveband light source 700 can operate using existing CWDM technology that operates with only a single wavelength per CWDM passband. In the second mode, the laser array 710 can emit light signals of at least a first wavelength and a second wavelength within the first CWDM passband. In this second mode, the waveband light source 700 can operate with other waveband devices to increase the number of wavelength transmission lanes of the CWDM technology.

[0070] In various examples, the waveband light source 700 can include a star coupler 720. As described above, the star coupler 720 can be any device (or combination of devices) that takes a given input signal and splits the signal into multiple output signals. Thus, the star coupler 720 can include any one or combination of: one or more multi-mode interference devices (MMIs); one or more optical multiplexers (e.g., micro-ring resonator / de-multiplexers, lattice filter multiplexers, micro-ring interleaver multiplexers, arrayed waveguide gratings, echelle gratings, etc.); and one or more optical de-multiplexers (e.g., micro-ring resonator / de-multiplexers, lattice filter de-multiplexers, micro-ring interleaver de-multiplexers, arrayed waveguide gratings, echelle gratings, etc.).

[0071] Thus, when the waveband light source 700 is operating in the second mode, the star coupler 720 can receive a first optical signal (FS) from a first input waveguide. FS can have a first wavelength within the first CWDM passband. Similarly, the star coupler 720 can receive a second optical signal (SS) from a second input waveguide. SS can have a second wavelength within the first CWDM passband. The star coupler 720 can receive FS and SS in any manner described. Figures 2 to 6 The star coupler 720 can also receive optical signals in other manners.

[0072] Upon receiving FS and SS, the star coupler 720 can combine versions of FS and SS onto a common waveguide. In other words, the star coupler 720 can combine a first version of FS (i.e., FS 1 ) with a first version of SS (i.e., SS 1 ) onto a first output waveguide. In various examples, FS 1 may be the same as FS. In other examples, FS 1 may be a power-reduced version of FS. SS 1 may be related to SS in the same / similar manner.

[0073] In some embodiments, the star coupler 720 can combine a first version of an additional optical signal onto the first output waveguide. For example, the laser array 712 can emit optical signals of a first wavelength and a second wavelength within a second CWDM passband (i.e., a second CWDM band). Therefore, the star coupler 720 can combine all of the following onto the first output waveguide: FS 1 (It is the first wavelength within the first CWDM passband); SS 1 (which is the second wavelength within the first CWDM passband); the first version of the third optical signal (which may be the first wavelength within the second CWDM passband); and the first version of the fourth optical signal (which may be the second wavelength within the second CWDM passband); and so on.

[0074] The star coupler 720 can be combined Figures 2 to 6 These optical signals can be combined in any of the ways described. The star coupler 720 can also combine these optical signals in other ways.

[0075] In various examples, the star coupler 720 can split a power-reduced version of the FS (and other optical signals) onto two or more output waveguides. For example, the star coupler 720 can split a first power-reduced version of the FS (e.g., FS...) onto two or more output waveguides. 1 The second power-reduced version of the FS (e.g., FS) is split onto the first output waveguide and the second power-reduced version of the FS is also split onto the first output waveguide. 2 The first optical signal is split onto the second output waveguide. In various examples, the first power-reduced version of the first optical signal (e.g., FS) is split onto the second output waveguide. 1 ) and a second power-reduced version of the first optical signal (e.g., FS) 2 (They may be the same.)

[0076] In the same / similar manner, star coupler 720 can split a power-reduced version of another received optical signal onto a first output waveguide and a second output waveguide. In some examples, star coupler 720 can split a power-reduced version of the received optical signal onto additional output waveguides (e.g., a third output waveguide, a fourth output waveguide, etc.). Star coupler 720 can be combined with... Figures 2 to 6 Any method described can be used to split the input / received optical signal into a reduced-power version. The star coupler 720 can also split the optical signal in other ways.

[0077] In some examples, band light source 700 (and band light sources 200 to 600) may include one or more optical modulators that are calibrated / tuned to modulate the emitted wavelength of the optical signal. (As will be combined...) Figures 8 to 12In more detail, an optical modulator can be an optical device that imparts data to an optical signal by modulating the optical signal. An optical modulator can be calibrated to modulate an optical signal of a specific wavelength. For example, a first optical modulator can be calibrated / tuned to modulate an optical signal of a first wavelength within a first CWDM passband. Similarly, a second optical modulator can be calibrated / tuned to modulate an optical signal of a second wavelength within the first CWDM passband.

[0078] The optical modulator included within the bandlight source 700 can be of various types. For example, if the bandlight source 700 emits an optical signal including the CWDM-4 band, the bandlight source 700 can utilize readily available direct-modulation lasers, electro-absorption modulated lasers, and other optical modulators using existing CWDM-4 technology. In some examples, the optical modulator can be a microring modulator. In other examples, the optical modulator can be a Mach-Zehnder modulator.

[0079] In some examples, the band light source 700 (or more specifically, its laser and optical modulator) can modulate the optical signal before the optical signal enters the star coupler 720 or after the optical signal leaves the star coupler 720. In other examples, the optical modulator can be incorporated into the star coupler 720. In still other examples, the optical signal generated by the band light source 700 can be modulated outside the band light source 700. Therefore, Figures 8 to 12 An example of a band transmitter that can externally modulate optical signals generated by band light sources 200 to 700 is described.

[0080] Figure 8 An example band transmitter according to various embodiments of the technology according to this disclosure is depicted. The band transmitter 800 includes a band demultiplexer (DEMUX), four wavelength DEMUXs, eight optical modulators, four wavelength multiplexers (MUX), a band MUX, and various waveguides connecting the aforementioned optical components.

[0081] Typically, a band transmitter can receive optical signals from one or more CWDM bands on a common waveguide. These bands may include two or more wavelengths.

[0082] Here, the band transmitter 800 can receive eight optical signals of eight different wavelengths on a single input waveguide (i.e., optical signals θ). 11 θ 12 θ 21 θ 22 θ 31 θ 32 θ 41 θ 42 These eight different wavelengths can include four CWDM bands, each with two wavelengths. For example, the optical signal θ 11 and θ12 The wavelength can constitute the first CWDM band; optical signal θ 21 and θ 22 The wavelength can constitute a second CWDM band; optical signal θ 31 and θ 32 The wavelength can constitute the third CWDM band; and the optical signal θ 41 and θ 42 The wavelengths can constitute a fourth CWDM band. In various examples, these CWDM bands can be CWMD-4 bands. In other examples, the band transmitter 800 can receive optical signals of different numbers of CWDM bands (e.g., optical signals of two bands, three bands, five bands, etc.). Similarly, CWDM bands can include additional wavelengths (e.g., three wavelengths per CWDM band, four wavelengths per CWDM band, etc.).

[0083] exist Figure 8 In a specific example, the band transmitter 800 receives optical signals from four CWDM bands, where each CWDM band includes two wavelengths. In other words, the band transmitter 800 can receive eight optical signals on a single input waveguide. Therefore, the band transmitter 800 can be used in combination with... Figures 2 to 7 It can be operated using any of the described band light sources. As mentioned above, each of these band light sources can generate eight optical signals (including four CWDM bands, each with two wavelengths) on at least one common output waveguide.

[0084] As described, the light signal θ 11 to θ 42 It is received by the band transmitter 800 and carried to the band DEMUX 810.

[0085] As a reverse device for an optical MUX, an optical DEMUX (such as the band DEMUX 810) can split a multiplexed beam into two or more beams based on wavelength / band. In other words, an optical DEMUX can receive multiple optical signals of different wavelengths / bands traveling on a common waveguide and split the optical signals onto separate waveguides according to wavelength / band. As used herein, a band demultiplexer (such as the band DEMUX 810) can refer to an optical demultiplexer that splits an input beam by band. For example, a band demultiplexer can split an input beam containing optical signals of multiple bands into separate beams containing optical signals of each band. In some examples, a wavelength demultiplexer can refer to an optical demultiplexer that splits a beam by wavelength. For example, a wavelength demultiplexer can split a beam containing optical signals of multiple wavelengths into separate beams containing optical signals of a single wavelength. Band demultiplexers and wavelength demultiplexers can be, but are not limited to, lattice filter demultiplexers, echelle gratings, and arrayed waveguide gratings that can be constructed / obtained from off-the-shelf silicon photonics factory process design kits.

[0086] Here, the DEMUX 810 can transmit the optical signal θ via the CWDM band. 11 to θ 42 The light is split into four separate waveguides (i.e., the DEMUX 810 band can split a single received beam into four CWDM bands). Specifically, the DEMUX 810 band can split the optical signal θ... 11 and θ 12 Split onto the first waveguide; the optical signal θ 21 and θ 22 Split onto the second waveguide; the optical signal θ 31 and θ 32 Split onto the third waveguide; and transmit the optical signal θ 41 and θ 42 It is split onto the fourth output waveguide.

[0087] Once split into wavelengths, the optical signal θ 11 to θ 42 This allows for further splitting of the optical signal into individual wavelengths, specifically DEMUX 820 to 826. Therefore, the optical signal θ 11 to θ 42 Each optical signal can be split onto a separate waveguide based on its corresponding wavelength. These waveguides can then carry the optical signals to optical modulators 830 to 837.

[0088] As described above, an optical modulator can be an optical device that imparts data to an optical signal by modulating the optical signal. Each optical modulator can be calibrated to modulate an optical signal of a specific wavelength. For example, optical modulator 830 can be calibrated to modulate the optical signal θ. 11The optical signal of wavelength θ can be modulated by the optical modulator 831. 12 The optical signal has a wavelength of [insert wavelength here]. Therefore, optical modulators 830 to 837 can assign individual data packets to the optical signal θ. 11 to θ 42 These modulated optical signals can be represented as optical signal θ'. 11 ,θ' 12 ,θ' 21 ,θ' 22 ,θ' 31 ,θ' 32 ,θ' 41 ,θ' 42 .

[0089] Optical modulators 830 to 837 can be of various types. For example, if the optical signal θ 11 to θ 42 Including the CWDM-4 band, optical modulators 830 to 837 can be off-the-shelf optical modulators using existing CWDM-4 technology. In some examples, optical modulators 830 to 837 can be microring modulators. In other examples, the microring modulator can be, but is not limited to, a Mach-Zehnder modulator or an electroabsorption modulator.

[0090] Modulated optical signal θ' 11 to θ' 42 It can be carried to wavelengths from 840 to 846.

[0091] As mentioned above, a MUX can refer to an optical device that combines optical signals of different wavelengths onto a common waveguide. As used herein, a wavelength multiplexer can refer to an optical multiplexer that combines two or more beams by wavelength. In other words, a wavelength multiplexer can combine a first beam containing a first optical signal of a first wavelength with a second beam containing a second optical signal of a second wavelength into a common beam. As used herein, a band multiplexer can refer to an optical multiplexer that combines two or more beams by band. For example, a band multiplexer can combine a first beam containing an optical signal of a first CWDM band with a second beam containing an optical signal of a second CWDM band into a common beam. Wavelength multiplexers and band multiplexers can be, but are not limited to, lattice filter multiplexers, microring multiplexers, and arrayed waveguide grating multiplexers that can be constructed / obtained from off-the-shelf silicon photonics fab process design kits.

[0092] Therefore, wavelengths MUX 840 to 846 can combine the received modulated optical signals (of different wavelengths) onto a common waveguide. Specifically, wavelength MUX 840 can combine the modulated optical signal θ' 11 and θ' 12Combined onto the first waveguide; the wavelength MUX 842 can modulate the optical signal θ' 21 and θ' 22 Combined with the second waveguide; wavelength MUX 844 can modulate the optical signal θ' 31 and θ' 32 Combined onto the third waveguide; and the wavelength MUX 846 can modulate the optical signal θ' 41 and θ' 42 They are combined onto the fourth waveguide. Each of these four waveguides can carry modulated optical signals in a common band to the MUX850 band.

[0093] The band MUX 850 can combine modulated optical signals from four bands onto a single output waveguide. As described below, these modulated optical signals can be carried to a band receiver operated to detect the modulated optical signals. This corresponds to the "read / extract" of data assigned to the modulated optical signals.

[0094] Similar to combination Figures 2 to 6 The described band light source, band transmitter 800, can also be operated using existing CWDM / CWDM-4 technologies. For example, band transmitter 800 can be operated using existing CWDM-4 technologies by tuning an even number of optical modulators (i.e., optical modulators 830, 832, 834, and 836) or an odd number of optical modulators (i.e., optical modulators 831, 833, 835, and 837) to modulate optical signals of CWDM-4 wavelengths. Similarly, the DEMUX and MUX of band transmitter 800 can be calibrated to split or combine optical signals of CWDM-4 wavelengths. Therefore, band transmitter 800 can be operated using existing CWDM-4 technologies as well as extended CWDM band technologies utilizing the present disclosure.

[0095] Figure 9 Another example band transmitter, illustrating various embodiments of the technology according to this disclosure, is described. The band transmitter 900 includes a band demultiplexer (DEMUX), eight micro-ring modulators, eight monitor photodetectors, a band multiplexer (MUX), and various waveguides connecting the aforementioned optical components.

[0096] Similar to band transmitter 800, band transmitter 900 can receive eight optical signals (i.e., optical signals) of eight different wavelengths on a single input waveguide. These eight different wavelengths can include four CWDM bands, each with two wavelengths. For example, optical signals. and The wavelengths can constitute the first CWDM band; optical signal and The wavelength can constitute a second CWDM band; optical signal and The wavelength can constitute the third CWDM band; and the optical signal and The wavelengths can constitute a fourth CWDM band. These CWDM bands can be CWMD-4 bands. In other examples, band transmitter 900 can receive optical signals from different numbers of CWDM bands. Similarly, CWDM bands can include additional wavelengths (e.g., three wavelengths per CWDM band, four wavelengths per CWDM band, etc.). Typically, a band transmitter (e.g., band transmitter 900) can receive optical signals from one or more CWDM bands on a common waveguide. These bands can include two or more wavelengths.

[0097] As described, light signals to It can be received by band transmitter 900 and carried to band DEMUX910 (band DEMUX910 can be the same as / similar to DEMUX 810). Therefore, band DEMUX910 can be combined with [other devices] according to the band. Figure 8 Splitting optical signals in the same / similar manner as described to (That is, the DEMUX910 band can split a received single beam into four CWDM bands). Specifically, the DEMUX910 band can split optical signals... and Split onto the first waveguide; transmit the optical signal and Split onto the second waveguide; transmit the optical signal and Split onto the third waveguide; and transmit the optical signal and It splits onto the fourth waveguide.

[0098] Micro-ring modulators 930a, 930b, 932a, 932b, 934a, 934b, 936a, and 936b can be coupled to these four waveguides. Specifically, micro-ring modulators 930a and 930b can be coupled to the first waveguide, micro-ring modulators 932a and 932b can be coupled to the second waveguide, micro-ring modulators 934a and 934b can be coupled to the third waveguide, and micro-ring modulators 936a and 936b can be coupled to the fourth waveguide.

[0099] A microring modulator can be an optical device that imparts data to an optical signal by modulating the optical signal. Here, each microring modulator can be tuned to modulate an optical signal of a specific wavelength while allowing optical signals of different wavelengths to pass through without interference. For example, microring modulator 930a can be tuned to modulate an optical signal. The wavelength of the light signal is allowed, while other wavelengths of light signals (e.g., light signals) are also permitted. It passes through undisturbed. Similarly, the micro-ring modulator 930b can be tuned to modulate the optical signal. The wavelength of the light signal is allowed, while other wavelengths of light signals (e.g., light signals) are also permitted. The light passes through undisturbed. The other micro-ring modulators depicted can be tuned in the same / similar manner. Therefore, these eight micro-ring modulators can modulate the optical signal. to These modulated optical signals can be represented as modulated optical signals. to In various embodiments, these microring modulators can be obtained from off-the-shelf silicon photonics factory process design kits or custom-designed.

[0100] The monitor photodetectors 920a, 920b, 922a, 922b, 924a, 924b, 926a, and 926b can be coupled to microring modulators 930a, 930b, 932a, 932b, 934a, 934b, 936a, and 936b, respectively. A monitor photodetector can refer to an optical device capable of detecting modulated or unmodulated optical signals of a certain wavelength (or multiple wavelengths). For example, monitor photodetector 920a can be tuned to detect modulated optical signals. The photodetector 920b can be tuned to detect modulated optical signals of a specific wavelength. The photodetector 922a can be tuned to detect the modulated optical signal of the specified wavelength. The modulated optical signal has a specific wavelength. Here, a monitor photodetector may be included within the band transmitter 900 to monitor and set the offset point of the modulator. In various embodiments, these monitor photodetectors may be obtained from off-the-shelf silicon photonics fab process design kits or custom-designed.

[0101] Once modulated, the optical signal to It can then be carried to band MUX 940 (the band can be the same as / similar to band MUX 850). For combination with Figure 8 In a similar manner, the band MUX 940 can combine modulated optical signals from four bands onto a single output waveguide. As described below, these modulated optical signals can be carried to a band receiver operated to detect the modulated optical signals. This corresponds to the "read / extract" of data assigned to the modulated optical signals.

[0102] Similar to band transmitter 800, band transmitter 900 can also operate using existing CWDM / CWDM-4 technologies. For example, band transmitter 900 can modulate optical signals of CWDM-4 wavelengths using existing CWDM-4 technologies by tuning "a" optical ring modulators (i.e., optical ring modulators 930a, 932a, 934a, and 936a) or "b" optical modulators (i.e., optical ring modulators 930b, 932b, 934b, and 936b). Similarly, the band DEMUX and band MUX of band transmitter 900 can be calibrated to split or combine optical signals of CWDM-4 wavelengths, respectively. Therefore, band transmitter 900 can operate using existing CWDM-4 technologies as well as extended CWDM band technologies utilizing the present disclosure.

[0103] Figure 10 Another example band transmitter is depicted, illustrating various examples of the technology according to this disclosure.

[0104] Similar to band transmitters 800 and 900, band transmitter 1000 can receive eight optical signals of eight different wavelengths on a single input waveguide (i.e., optical signal β). 11 β 12 β 21 β 22 β 31 β 32 β 41 β 42 These eight different wavelengths can include four CWDM bands, each with two wavelengths. For example, the optical signal β 11 and β 12 The wavelength can constitute the first CWDM band; optical signal β 21 and β 22 The wavelength can constitute a second CWDM band; optical signal β 31 and β 32 The wavelength can constitute the third CWDM band; and the optical signal β 41 and β 42 The wavelengths can constitute a fourth CWDM band. In various examples, these CWDM bands can be CWMD-4 bands. In other examples, the band transmitter 1000 can receive optical signals from different numbers of CWDM bands. Similarly, CWDM bands can include additional wavelengths (e.g., three wavelengths per CWDM band, four wavelengths per CWDM band, etc.). Typically, a band transmitter (e.g., band transmitter 1000) can receive optical signals from one or more CWDM bands on a common waveguide. These bands can include two or more wavelengths.

[0105] As mentioned above, the first wavelength of each CWDM band (i.e., the optical signal β) 11β 21 β 31 and β 41 The wavelength of the light signal (β) can be referred to as the "odd wavelength". The second wavelength of each CWDM band (i.e., the optical signal β) can be called the "odd wavelength". 12 β 22 β 32 and β 42 The wavelength of an even number (e.g., 10 ...

[0106] As described, the light signal β 11 To β 42 It can be received by the band transmitter 1000 and carried to the interleaver DEMUX 1010. An interleaver DEMUX can refer to an optical device that splits multiplexed optical signals of odd and even wavelengths onto separate waveguides. Therefore, the interleaver DEMUX 1010 can split odd-wavelength optical signals (e.g., optical signal β) onto separate waveguides. 11 β 21 β s1 and β 41 The optical signal is split onto the first waveguide and the even-wavelength optical signal (e.g., optical signal β) is split into two waves. 12 β 22 β 32 and β 42 It is split onto the second waveguide.

[0107] Even-numbered and odd-numbered optical signals can be carried to DEMUX 1020 and 1022 respectively on their corresponding waveguides. DEMUX 1020 and 1022 can split the received optical signals onto separate waveguides by wavelength. Specifically, DEMUX 1020 can split odd-numbered wavelength optical signals (e.g., optical signal β) onto separate waveguides by wavelength. 11 β 21 β 31 and β 41 The signal is split into four separate waveguides. For example, the DEMUX 1020 can split the optical signal β onto four separate waveguides. 11 Split onto the first waveguide; transmit the optical signal β 21 Split onto the second waveguide; the optical signal β 31 Split onto the third waveguide; and transmit the optical signal β 41 Split onto the fourth waveguide. The DEMUX 1022 can split even-numbered wavelength optical signals (e.g., optical signal β) in the same / similar manner. 12 β 22 β 32 and β 42In various embodiments, DEMUX 1020 and 1022 may be, but are not limited to, lattice filter DEMUX, micro-ring DEMUX, arrayed waveguide grating DEMUX, and echelle grating DEMUX that can be constructed / obtained from off-the-shelf silicon photonics factory process design kits.

[0108] Once on its corresponding waveguide, an optical signal of a given wavelength can be carried to an optical modulator, which is calibrated to modulate the optical signal of the given wavelength. For example, optical signal β 11 It can be carried to an optical modulator 1031, which can be calibrated to modulate the optical signal β. 11 The optical signal is at a specific wavelength. Other optical signals can be modulated in the same / similar way.

[0109] As described above, optical modulators 1030 to 1037 can be various types of optical modulators. For example, if the optical signal β 11 To β 42 Including the CWDM-4 band, optical modulators 1030 to 1037 can be off-the-shelf optical modulators using existing CWDM-4 technology. In some examples, optical modulators 1030 to 1037 can be micro-ring modulators. In other examples, the optical modulator can be a Mach-Zehnder modulator.

[0110] Odd-number modulated optical signals (the modulated optical signals can be represented as β') 11 ,β' 21 ,β' 31 and β' 41 ) can be carried to the MUX 1040, and even-numbered modulated optical signals (the modulated optical signals can be represented as β') 12 ,β' 22 ,β' 32 and β' 42 The modulated optical signal can be carried to MUX 1042. In the same / similar manner as described in the previous images, MUX 1040 can combine odd-numbered modulated optical signals onto one waveguide, and MUX 1042 can combine even-numbered modulated optical signals onto another waveguide. These two waveguides can then carry the modulated optical signal to the interleaver MUX 1050.

[0111] An interleaver (MUX) can refer to an optical device that combines odd-wavelength optical signals with even-wavelength optical signals onto a common waveguide. Therefore, the MUX 1050 can combine odd-wavelength modulated optical signals (e.g., optical signal β') onto a common waveguide. 11 ,β' 21 ,β' 31 and β' 41 ) and modulated optical signals of even wavelengths (e.g., optical signal β')12 ,β' 22 ,β' 32 and β' 42 These modulated optical signals are combined onto a common output waveguide. As will be described below, these modulated optical signals can be carried to a band receiver operated to detect the modulated optical signals. This corresponds to the "read / extract" of data assigned to the modulated optical signals.

[0112] Similar to band transmitters 800 and 900, band transmitter 1000 can also operate using existing CWDM / CWDM-4 technologies. For example, band transmitter 1000 can modulate optical signals of CWDM-4 wavelengths using existing CWDM-4 technologies by tuning odd-numbered optical modulators (i.e., optical modulators 1031, 1033, 1035, and 1037) or even-numbered optical modulators (i.e., optical modulators 1030, 1032, 1034, and 1036). Similarly, the DEMUX and MUX of band transmitter 1000 can be calibrated to split or combine optical signals of CWDM-4 wavelengths. Therefore, band transmitter 1000 can be operated using existing CWDM-4 technologies as well as extended CWDM band technologies utilizing the present disclosure.

[0113] Figure 11 Another example band transmitter is depicted, illustrating various embodiments of the technology according to this disclosure. Band transmitter 1100 includes a micro-ring interleaver DEMUX, two additional DEMUXs following the micro-ring interleaver DEMUX, eight Mach-Zehnder modulators, two MUXs, one micro-ring interleaver MUX, and various waveguides connecting the aforementioned optical components.

[0114] Similar to band transmitters 800 to 1000, band transmitter 1100 can receive eight optical signals of eight different wavelengths on a single input waveguide (i.e., optical signal κ). 11 κ 12 κ 21 κ 22 κ 31 κ 32 κ 41 κ 42 These eight different wavelengths can include four CWDM bands, each with two wavelengths. For example, the optical signal κ... 11 and κ 12 The wavelength can constitute the first CWDM band; optical signal κ 21 and κ 22 The wavelength can constitute a second CWDM band; optical signal κ 31 and κ 32 The wavelength can constitute the third CWDM band; and the optical signal κ 41 and κ 42The wavelengths can constitute a fourth CWDM band. In various examples, these CWDM bands can be CWDM-4 bands. In other examples, band transmitter 1100 can receive optical signals from different numbers of CWDM bands. Similarly, CWDM bands can include additional wavelengths (e.g., three wavelengths per CWDM band, four wavelengths per CWDM band, etc.). Typically, a band transmitter (e.g., band transmitter 1100) can receive optical signals from one or more CWDM bands on a common waveguide. These bands can include two or more wavelengths.

[0115] As mentioned above, the first wavelength of each CWDM band (i.e., the optical signal κ) 11 κ 21 κ 31 and κ 41 The wavelength of the light signal (κ) can be referred to as the "odd wavelength". The second wavelength of each CWDM band (i.e., the optical signal κ) can be called the "odd wavelength". 12 κ 22 κ 32 and κ 42 The wavelength of an even number (e.g., 10 ...

[0116] As described, the light signal κ 11 To κ 42 The signal can be received by the band transmitter 1100 and carried to the micro-ring interleaver DEMUX 1110. An interleaver DEMUX can refer to an optical device that splits multiplexed optical signals of odd and even wavelengths onto separate waveguides. The micro-ring interleaver DEMUX 1110 can act as a filter for optical signals of certain wavelengths. Specifically, the micro-ring interleaver DEMUX 1110 can be tuned to split odd-numbered optical signals (e.g., optical signal κ) onto separate waveguides. 11 κ 21 κ 31 κ 41 The signal is "distributed" to carry odd-numbered optical signals onto the waveguide of the DEMUX 1120, while allowing even-numbered optical signals (e.g., optical signal κ) to also be carried. 12 κ 22 κ 32 κ 42 The micro-ring interleaver DEMUX 1110 can transmit odd-numbered and even-numbered optical signals (e.g., optical signal κ) without interference. 11 To κ 42 () Split onto individual waveguides.

[0117] In some examples, the microring interleaver DEMUX 1110 can have a periodic free spectral range (FSR). This FSR allows the microring interleaver DEMUX 1110 to "divide" optical signals of wavelengths spaced apart at a certain interval. For example, the FSR of the microring interleaver DEMUX can be tuned to "divide" equal to the optical signal κ. 11 κ 21 κ 31 κ 41 Optical signals with odd wavelengths. In some embodiments, these odd wavelengths may be spaced approximately 20 nm apart.

[0118] Even-numbered and odd-numbered optical signals can be carried to DEMUX 1120 and 1122 respectively on their corresponding waveguides. DEMUX 1120 and 1122 can split the received optical signals onto separate waveguides by wavelength. Specifically, DEMUX 1120 can split odd-numbered wavelength optical signals (e.g., optical signal κ) onto separate waveguides by wavelength. 11 κ 21 κ 31 κ 41 The signal is split into four separate waveguides. For example, the DEMUX 1120 can split the optical signal into four separate waveguides. 11 Split onto the first waveguide; transmit the optical signal κ 21 Split onto the second waveguide; transmit the optical signal κ 31 Split onto the third waveguide; and transmit the optical signal κ 41 Split onto the fourth waveguide. The DEMUX 1122 can split even-numbered wavelength optical signals (e.g., optical signal κ) in the same / similar manner. 12 κ 22 κ 32 κ 42 In various embodiments, DEMUX 1120 and 1122 may be, but are not limited to, lattice filter DEMUX, micro-ring DEMUX, arrayed waveguide grating DEMUX, and echelle grating DEMUX that can be designed / constructed / obtained from off-the-shelf silicon photonics factory process design kits.

[0119] Once on its corresponding waveguide, an optical signal of a given wavelength can be carried to a Mach-Zehnder modulator, which is calibrated to modulate the optical signal of the given wavelength. For example, the optical signal κ 11 It can be carried to an optical modulator 1131, which can be calibrated to modulate the optical signal κ. 11 The optical signal is at a specific wavelength. Other optical signals can be modulated in the same / similar way.

[0120] Odd-number modulated optical signals (which can be represented as κ') 11 ,κ' 21,κ' 31 ,κ' 41 ) can be carried to the MUX 1140, and even-numbered modulated optical signals (which can be represented as κ') 12 ,κ' 22 ,κ' 32 ,κ' 42 The modulated optical signal can be carried to MUX 1142. In the same / similar manner as described in the previous images, MUX 1140 can combine odd-numbered modulated optical signals onto one waveguide, and MUX 1142 can combine even-numbered modulated optical signals onto another waveguide. These two waveguides can then carry the modulated optical signal to the microring interleaver MUX 1150.

[0121] A micro-loop interleaver (MUX) can be an optical device that combines optical signals of odd and even wavelengths onto a common fiber / waveguide. The MUX 1150 can act as a filter for optical signals of certain wavelengths. Specifically, the MUX 1150 can be tuned to combine odd-modulated optical signals (e.g., optical signal κ') 11 ,κ' 21 ,κ' 31 ,κ' 41 The signal is "distributed" onto the waveguide carrying an even number of modulated optical signals, while simultaneously allowing even numbers of optical signals (e.g., optical signal κ') to be transmitted. 12 ,κ' 22 ,κ' 32 ,κ' 42 The micro-loop interleaver MUX 1150 can transmit both odd-modulated and even-modulated optical signals (e.g., optical signal κ') without interference. 11 To κ' 42 These modulated optical signals are combined onto a single output waveguide. As will be described below, these modulated optical signals can be carried to a band receiver operated to detect the modulated optical signals. This corresponds to the "read / extract" of data assigned to the modulated optical signals.

[0122] In some examples, the micro-ring interleaver MUX 1150 can have a periodic free spectral range (FSR). This FSR allows the micro-ring interleaver MUX 1150 to "divide" optical signals of wavelengths spaced apart at a certain interval. For example, the FSR of the micro-ring interleaver DEMUX can be tuned to be "divided" to be equal to the modulated optical signal κ'. 11 ,κ' 21 ,κ' 31 ,κ' 41 Optical signals with odd wavelengths. In some embodiments, these odd wavelengths may be spaced approximately 20 nm apart.

[0123] Similar to band transmitters 800 to 1000, band transmitter 1100 can also operate using existing CWDM / CWDM-4 technologies. For example, band transmitter 1100 can modulate optical signals of CWDM-4 wavelengths using existing CWDM-4 technologies by tuning odd-numbered optical modulators (i.e., optical modulators 1131, 1133, 1135, and 1137) or even-numbered optical modulators (i.e., optical modulators 1130, 1132, 1134, and 1136). Similarly, the DEMUX and MUX of band transmitter 1100 can be calibrated to split or combine optical signals of CWDM-4 wavelengths. Therefore, band transmitter 1100 can be operated using existing CWDM-4 technologies as well as extended CWDM band technologies utilizing the present disclosure.

[0124] Figure 12 Another example band transmitter is depicted, illustrating various examples of the technology according to this disclosure. Band transmitter 1200 can be considered as a general-purpose band transmitter from band transmitter 800 to 1100.

[0125] The band transmitter 1200 may include: a combination of one or more optical demultiplexers 1210; at least a first optical modulator 1220 and a second optical modulator 1222; and a combination of one or more optical multiplexers 1230. These components may be connected via various waveguides.

[0126] A combination of one or more optical multiplexers 1210 can split an input beam into at least a first demultiplexed beam and a second demultiplexed beam.

[0127] The input beam may include at least a first optical signal (FS) and a second optical signal (SS). FS may be a first wavelength in a first CWDM band, and SS may be a second wavelength in the first CWDM band. The first CWDM band may include at least a first wavelength and a second wavelength within a first CWDM passband. The first CWDM passband may include a wavelength spectrum comprising the first CWDM wavelength that can be passed through an optical filter. In various examples, the input beam may include optical signals in additional CWDM bands (e.g., optical signals in a second CWDM band, optical signals in a third CWDM band, etc.), or optical signals with additional wavelengths within the first CWDM passband / band (e.g., optical signals with a third wavelength within the first CWDM passband, optical signals with a fourth wavelength within the first CWDM passband, etc.).

[0128] A demultiplexed beam can refer to a beam that has been split by one or more optical demultiplexers (this can include a beam that was initially split by an optical demultiplexer and then combined with another beam using an optical multiplexer).

[0129] The first demultiplexed beam may include at least the FS. In various examples, the first demultiplexed beam may include an optical signal with an additional wavelength. For example, in band transmitter 900, the first demultiplexed beam will include FS and SS (whose wavelengths include the first and second wavelengths of the first CWDM band, respectively). Similarly, in band transmitter 900, the second demultiplexed beam will include a third and a fourth optical signal, wherein the third and fourth optical signals are the first and second wavelengths of the second CWDM band, respectively.

[0130] The second demultiplexed beam may include at least one optical signal of a wavelength different from FS. In some embodiments, such as band transmitters 800, 1000, and 1100, the second demultiplexed beam may include SS. In other examples, such as band transmitter 900, SS may alternatively be a portion of the first demultiplexed beam. Therefore, at least one optical signal of a wavelength different from FS may be, for example, a third optical signal, a fourth optical signal, etc. Here, the third optical signal may be a first wavelength of the second CWDM band, the fourth optical signal may be a second wavelength of the second CWDM band, etc.

[0131] A combination of one or more optical multiplexers 1210 can split an input beam into additional demultiplexed beams. For example, a combination of one or more optical multiplexers 1210 can split the input beam into a first demultiplexed beam, a second demultiplexed beam, a third demultiplexed beam, and so on. In some embodiments, each of these demultiplexed beams may include a separate CWDM band optical signal. For example, the first demultiplexed beam may include a first CWDM band optical signal, the second demultiplexed beam may include a second CWDM band optical signal, the third demultiplexed beam may include a third CWDM band optical signal, and so on.

[0132] The combination of one or more optical demultiplexers 1210 can include any number and any type of optical demultiplexers.

[0133] For example, according to band transmitter 800, a combination of one or more optical demultiplexers 1210 may include a band demultiplexer and multiple wavelength demultiplexers. As used herein, a band demultiplexer may refer to an optical demultiplexer that splits an input beam by band. For example, a band demultiplexer can split an input beam comprising optical signals of multiple bands into separate beams comprising optical signals of each band. In some examples, a wavelength demultiplexer may refer to an optical demultiplexer that splits a beam by wavelength. For example, a wavelength demultiplexer can split a beam comprising optical signals of multiple wavelengths into separate beams comprising optical signals of a single wavelength. Band demultiplexers and wavelength demultiplexers may be, but are not limited to, lattice filter demultiplexers, microring demultiplexers, arrayed waveguide grating demultiplexers, or echelle grating demultiplexers that can be designed / constructed / obtained from off-the-shelf silicon photonics fab process design kits.

[0134] In another example, depending on the band transmitter 900, a combination of one or more optical demultiplexers 1210 may include a single band demultiplexer (which may also be designed / constructed / obtained from off-the-shelf silicon photonics factory process design kits).

[0135] In some examples (e.g., band transmitters 1000 and 1100, respectively), a combination of one or more optical demultiplexers 1210 may also include an interleaver demultiplexer (which can split the input beam into a first beam comprising an odd-wavelength optical signal and a second beam comprising an even-wavelength optical signal) and a microring interleaver demultiplexer. As described above, the microring interleaver demultiplexer may be a specific type of interleaver demultiplexer that acts as a “splitter” filter for either odd-wavelength or even-wavelength optical signals that are periodically spaced apart on the electromagnetic spectrum.

[0136] The first optical modulator (i.e., optical modulator 1220) can modulate the first demultiplexed beam by modulating the FS. As described above, the optical modulator can be an optical device that imparts data to an optical signal by modulating the optical signal. The optical modulator can be calibrated to modulate an optical signal of a certain wavelength. For example, the optical modulator 1220 can be calibrated to modulate an optical signal of the wavelength of the FS (i.e., the first wavelength of the first CWDM band).

[0137] The optical modulator 1220 can be any type of optical modulator. For example, if FS is a first CWDM-4 wavelength, the optical modulator 1220 can be an off-the-shelf optical modulator using existing CWDM-4 technology. In some examples, the optical modulator 1220 can be a micro-ring modulator tuned to modulate an optical signal of the wavelength of FS. In other examples, the optical modulator 1220 can be a Mach-Zehnder modulator.

[0138] The second optical modulator (i.e., optical modulator 1222) can modulate the second demultiplexed beam by modulating at least one optical signal with a wavelength different from FS. Similar to optical modulator 1220, optical modulator 1222 can be any type of optical modulator. Therefore, optical modulator 1222 can be calibrated / tuned to modulate an optical signal with a wavelength different from FS. For example, if the at least one optical signal with a wavelength different from FS is SS, optical modulator 1222 can be calibrated / tuned to modulate an optical signal with a second wavelength in a first CWDM band. Conversely, if the at least one optical signal with a wavelength different from FS is a third optical signal, and the third optical signal is a first wavelength in a second CWDM band, optical modulator 1222 can be calibrated / tuned to modulate an optical signal with a first wavelength in a second CWDM band.

[0139] In some examples, the band transmitter 1200 may include additional optical modulators. Therefore, each optical modulator can be calibrated / tuned to modulate optical signals of different wavelengths within the respective CWDM passband.

[0140] A combination of one or more optical multiplexers 1230 can combine a modulated first demultiplexed beam and a modulated second demultiplexed beam into a modulated output beam.

[0141] A combination of one or more optical multiplexers 1230 may include any number and any type of optical multiplexers.

[0142] For example, according to band transmitter 800, a combination of one or more optical multiplexers 1230 may include multiple wavelength multiplexers and one band multiplexer. A wavelength multiplexer may refer to an optical multiplexer that combines wavelengths. For example, a wavelength multiplexer can combine a first beam of light including a first optical signal of a first wavelength with a second beam of light including a second optical signal of a second wavelength into a common beam. As used herein, a band multiplexer may refer to an optical multiplexer that combines bands. In other words, a band multiplexer can combine a first beam of light including an optical signal of a first CWDM band with a second beam of light including an optical signal of a second CWDM band into a common beam. Wavelength multiplexers and band multiplexers may be, but are not limited to, lattice filter multiplexers, microring multiplexers, arrayed waveguide grating multiplexers, and echelle grating multiplexers that can be designed / constructed / obtained from off-the-shelf silicon photonics factory process design kits.

[0143] In another example, depending on the band transmitter 900, a combination of one or more optical multiplexers 1230 may include a single band multiplexer (which may also be designed / constructed / obtained from off-the-shelf silicon photonics factory process design kits).

[0144] In some examples (e.g., band transmitters 1000 and 1100, respectively), a combination of one or more optical multiplexers 1230 may also include an interleaved multiplexer (which can combine a first beam of optical signals including odd wavelengths and a second beam of optical signals including even wavelengths into a common beam) and a micro-ring interleaved multiplexer (which may be a specific type of interleaved multiplexer that acts as a “splitter” filter for optical signals of odd or even wavelengths spaced at periodic intervals).

[0145] Similar to band transmitters 800 to 1100, band transmitter 1200 can also operate using existing CWDM / CWDM-4 technologies. For example, band transmitter 1200 can be combined with existing CWDM-4 technologies by at least tuning a first optical modulator 1220 to modulate an optical signal of a first CWDM-4 wavelength. Similarly, combinations of one or more demultiplexers 1210 and one or more multiplexers 1230 can be calibrated to split or combine optical signals of CWDM-4 wavelengths. Therefore, band transmitter 1200 can operate using existing CWDM-4 technologies as well as extended CWDM band technologies utilizing the present disclosure.

[0146] Figure 13 Example band receivers according to various embodiments of the technology of this disclosure are depicted. Band receiver 1300 may include a polarization beam splitter, a polarization rotator, two band demultiplexers, eight wavelength demultiplexers, eight phase shifters, eight waveguide photodetectors, and various waveguides connecting the above components.

[0147] Typically, a band receiver can detect modulated optical signals from one or more CWDM bands received from a common waveguide. These bands may include two or more wavelengths. As described above, by detecting the modulated optical signals, the band receiver can read / extract the data assigned to the modulated optical signals. Here, the band receiver 1300 can receive eight modulated optical signals (i.e., optical signals ψ') at eight different wavelengths on a single input waveguide. 11 、ψ' 12 、ψ' 21 、ψ' 22 、ψ' 31 、ψ' 32 、ψ' 41 、ψ' 42 These eight different wavelengths can include four CWDM bands, each with two wavelengths. For example, the optical signal ψ' 12 and ψ' 21 The wavelength can constitute the first CWDM band; optical signal ψ' 21 and ψ'22 The wavelength can constitute a second CWDM band; optical signal ψ' 31 and ψ' 32 The wavelength can constitute the third CWDM band; and the optical signal ψ' 41 and ψ' 42 The wavelengths can constitute a fourth CWDM band. In various examples, these CWDM bands can be CWMD-4 bands. In other examples, the band receiver 1300 can receive modulated optical signals of different numbers of CWDM bands (e.g., optical signals of two bands, three bands, five bands, etc.). Similarly, CWDM bands can include additional wavelengths (e.g., three wavelengths per CWDM band, four wavelengths per CWDM band, etc.).

[0148] exist Figure 13 In a specific example, band receiver 1300 receives optical signals from four CWDM bands, where each CWDM band includes two wavelengths. In other words, band receiver 1300 can receive eight optical signals on a single input waveguide. Therefore, band receiver 1300 can be used in combination with... Figures 2 to 12 Any of the described band light sources and band transmitters can be used for operation. As a reminder above, each of these band light sources can generate optical signals of eight different wavelengths (including four CWDM bands, each with two wavelengths), and each of the band transmitters can modulate these eight wavelength optical signals.

[0149] In each example, the band receiver 1300 can implement a polarization diversity scheme.

[0150] Polarization is a property of transverse waves (such as electromagnetic waves) that specifies the geometric direction of vibration. In a transverse wave, the direction of vibration is perpendicular to the direction of wave motion. Electromagnetic waves, such as light, are composed of coupled vibrating electric and magnetic fields that are usually perpendicular to each other. Typically, when light travels in an optical fiber / waveguide, polarization rotation is allowed. Therefore, when the band receiver 1300 receives the modulated optical signal ψ' 11 to ψ' 42 In this case, the modulated optical signal will typically have an unknown polarization. In other words, the directions of the vibrating electric and magnetic fields of these optical signals may be unknown.

[0151] Typically, the response of an optical receiver depends on polarization. In other words, an optical receiver may respond better to one polarization than to another. Similarly, optical waveguides are typically polarization-dependent, and photonic integrated circuits are more easily designed for individual polarizations. Therefore, many photonic integrated circuits, especially those found in silicon factory PDKs, are polarization-dependent, and the optics built from these waveguides are optimized for individual polarizations. In most cases, these optics are optimized for TE modes.

[0152] Therefore, waveguide 1302 can be polarization-dependent. In other words, waveguide 1302 can have two modes. The first mode can be transverse electric (TE) mode. The modulated optical signal ψ' 11 to ψ' 42 The vibrational electric field can partially activate the TE mode. This TE mode can have a known polarization state (e.g., a "horizontal" polarization state). The second mode can be a transverse magnetic (TM) mode. The modulated optical signal ψ' 11 to ψ' 42 The vibrational electric field can partially activate this TM mode. This TM mode can have a known polarization state (e.g., a "vertical" polarization state). As part of the polarization diversity scheme of the band receiver 1300, the two modes can be spatially split onto two separate waveguides.

[0153] Therefore, waveguide 1302 can modulate the optical signal ψ' 11 to ψ' 42 The beam is carried to the polarization beam splitter 1310. The polarization beam splitter can refer to splitting a light beam (such as including modulated optical signals ψ') into two beams. 11 to ψ' 42 An optical device that splits a beam of light into two physically separate beams orthogonal to each other and having a known polarization state. Therefore, the polarization beam splitter 1310 can split a beam including a modulated optical signal ψ' 11 to ψ' 42 The light beam is split into two separate beams. The first beam may include the TE mode (i.e., the "horizontal" polarization state) of the input beam and may continue to propagate along waveguide 1304 (which may have only a single TE mode). The second beam may include the TM mode (i.e., the "vertical" polarization state) of the input beam and may continue to propagate along waveguide 1306 (which may have only a single TM mode). The modulated optical signal of this first beam can be represented as the modulated optical signal ψ'. 11(TE) to ψ' 42(TE) The modulated optical signal of the second beam can be represented as optical signal ψ'. 11(TM) to' 42(TM) (Not depicted).

[0154] In some examples, waveguide 1306 can modulate the optical signal ψ' 11(TM) to ψ' 42(TM) The signal is carried to polarization rotator 1320. A polarization rotator can refer to an optical device that rotates the polarization state of a light beam. Therefore, polarization rotator 1320 can carry the modulated light signal ψ' to the polarization rotator. 11(TM) to ψ' 42(TM) The polarization state is rotated by 90 degrees, so that the modulated optical signal also propagates in TE mode. The rotated modulated optical signal can be represented as ψ' 11(TF’) to ψ' 42(TE') It can also propagate along waveguide 1308 in TE mode.

[0155] After polarization beam splitting (and in some examples, polarization rotation), the modulated optical signal with known polarization can be carried to a band demultiplexer. Specifically, waveguide 1304 can carry the modulated optical signal ψ' 11(TE) to ψ' 42(TE) The signal is carried to the band demultiplexer 1330, and the waveguide 1308 can carry the modulated optical signal ψ'. 11(TE’) to ψ' 42(TE’) It is carried to the band demultiplexer 1332.

[0156] Band demultiplexers 1330 and 1332 may be the same as / similar to the band demultiplexer described in conjunction with the previous images. Therefore, band demultiplexer 1330 can split the modulated optical signal ψ' by band. 11(TE) to ψ' 42(TE) (that is, the modulated optical signal ψ') 11(TE) and ψ' 12(TE) It can be split onto the first waveguide; modulated optical signal ψ' 21(TE) and ψ' 22(TE) (It can be split onto a second waveguide, etc.). In the same / similar way, the band demultiplexer 1332 can split the modulated optical signal ψ' via band. 11(TE’) to ψ' 42(TE’) (that is, the modulated optical signal ψ') 11(TE’) and ψ' 12(TE') It can be split onto the first waveguide; modulated optical signal ψ' 21(TE’) and ψ' 22(TE’) It can be split onto a second waveguide, etc.

[0157] After the modulated optical signal has been split across wavelengths, it can be carried to wavelength demultiplexers 1340 to 1347. These wavelength demultiplexers can be the same as / similar to those described in conjunction with the previous figures. Therefore, the wavelength demultiplexers can split the modulated optical signal by wavelength. For example, wavelength demultiplexer 1340 can split the modulated optical signal ψ'11(TE) and ψ' 12(TE) The wavelength is split into two separate waveguides; the wavelength demultiplexer 1341 can convert the modulated optical signal ψ' 21(TE) and ψ' 22(TE) Split onto the second waveguide; and so on. In the same / similar manner, the wavelength demultiplexer 1344 can convert the modulated optical signal ψ' 11(TE’) and ψ' 12(TE' The wavelength is split into two separate waveguides; the wavelength demultiplexer 1345 can convert the modulated optical signal ψ' 21(TE') and ψ' 22(TE') Split into two separate waveguides; and so on.

[0158] Once the optical signal ψ' is modulated 11(TE) to ψ' 42(TE) (That is, the optical signal propagating along waveguide 1304) has been split onto its own individual waveguide, and the modulated optical signal can then be carried to waveguide photodetectors 1360 to 1367. A waveguide photodetector can refer to an optical device that, when mounted on a waveguide, can detect modulated optical signals. In some examples, waveguide photodetectors can be calibrated to detect modulated optical signals of a specific wavelength. For example, waveguide photodetector 1360 can be calibrated to detect the modulated optical signal ψ'. 11(TE) The modulated optical signal at the wavelength (i.e., the first wavelength of the first CWDM band). In the same / similar manner: the waveguide photodetector 1361 can be calibrated to detect the modulated optical signal ψ'. 12(TE) The modulated optical signal at the wavelength (i.e., the second wavelength of the first CWDM band) can be used to calibrate the waveguide photodetector 1362 to detect the modulated optical signal ψ'. 21(TE) The modulated optical signal at the wavelength (i.e., the first wavelength of the second CWDM band) can be used to calibrate the waveguide photodetector 1363 to detect the modulated optical signal ψ'. 22(TE) Modulated optical signals of wavelength (i.e., the second wavelength of the second CWDM band); etc.

[0159] In the same / similar manner, the optical signal ψ' is modulated. 11(TE’) to ψ' 42(TE’) (That is, the optical signal propagating along waveguide 1308) can be carried to waveguide photodetectors 1360 to 1367 and detected by said waveguide photodetectors. For example, waveguide photodetector 1360 can be calibrated to detect the modulated optical signal ψ'. 11(TE’) The modulated optical signal at the wavelength (i.e., the first wavelength of the first CWDM band). In the same / similar manner: the waveguide photodetector 1361 can be calibrated to detect the modulated optical signal ψ'. 12(TE')The modulated optical signal at the wavelength (i.e., the second wavelength of the first CWDM band) can be used to calibrate the waveguide photodetector 1362 to detect the modulated optical signal ψ'. 21(TE’) The modulated optical signal at the wavelength (i.e., the first wavelength of the second CWDM band) can be used to calibrate the waveguide photodetector 1363 to detect the modulated optical signal ψ'. 22(TE') Modulated optical signals of wavelength (i.e., the second wavelength of the second CWDM band); etc.

[0160] Therefore, waveguide photodetectors 1360 to 1367 can detect the modulated optical signal ψ' 11(TE) to' 42(TE) and ψ' 11(TE’) to ψ' 42(TE’) This can correspond to reading / extracting the data assigned to the modulated optical signal.

[0161] In some examples, the optical signal ψ' is modulated before detection by waveguide photodetectors 1360 to 1367. 11(TE) to ψ' 42(TE) and modulated optical signal ψ' 11(TE’) to ψ' 42(TE’) One (or both) of them can be transmitted via one of phase shifters 1370 to 1377. A phase shifter is an optical device that directs the phase shift of an optical signal. Therefore, the band receiver 1300 may include a phase shifter to account for any polarization mode dispersion in the optical fiber and the time delay caused by the modulated optical signal reaching the waveguide photodetector via different paths (e.g., waveguide 1308 may be larger than waveguide 1304). For example, the modulated optical signal ψ' is transmitted via one of the phase shifters 1370 to the waveguide photodetector 1360. 11(TE’) The signal can be transmitted via phase shifter 1370 to ensure that when the two modulated optical signals are detected by waveguide photodetector 1360, the modulated optical signal ψ' 11(TE’) With modulated optical signal ψ' 11(TE) Same phase. Here, the modulated optical signals have the same phase and arrive simultaneously when they are detected, which is ideal to ensure that the waveguide photodetector receives the same data stream from the left and right sides.

[0162] Similar to band transmitters 800 to 1200, band receiver 1300 can also operate using existing CWDM / CWDM-4 technology. For example, band receiver 1300 can be configured using existing CWDM-4 technology by calibration / tuning to combine: waveguide photodetector 1360 to detect a modulated optical signal at a first CWDM-4 wavelength; waveguide photodetector 1362 to detect a modulated optical signal at a second CWDM-4 wavelength; waveguide photodetector 1364 to detect a modulated optical signal at a third CWDM-4 wavelength; and waveguide photodetector 1366 to detect a modulated optical signal at a fourth CWDM-4 wavelength. Similarly, other optical components of band receiver 1300 can be calibrated / tuned to operate with these CWDM-4 wavelengths. Therefore, band receiver 1300 can operate using existing CWDM-4 technology, as well as scaling techniques utilizing the CWDM bands disclosed herein.

[0163] Similar to the aforementioned band devices, the band receiver 1300 can be constructed using many off-the-shelf building blocks found in silicon photonics and III-V factory process design kits (e.g., broadband fiber-to-chip couplers, CWDM-4 waveguide photodetectors, etc.).

[0164] Figure 14 Another example band receiver is depicted, illustrating various embodiments of the technology according to this disclosure. The band receiver 1400 may include a polarization beamsplitter, a polarization rotator, two band demultiplexers, eight microring resonators / splitters, various phase shifters, eight waveguide photodetectors, and various waveguides connecting the aforementioned components.

[0165] Similar to band receiver 1300, band receiver 1400 can detect modulated optical signals from one or more CWDM bands received from a common waveguide. These bands may include two or more wavelengths. As described above, by detecting the modulated optical signals, the band receiver can read / extract the data assigned to the modulated optical signals.

[0166] Here, the band receiver 1400 can receive eight modulated optical signals (i.e., modulated optical signals) of eight different wavelengths on a single input waveguide. These eight different wavelengths can include four CWDM bands, each with two wavelengths. For example, optical signals. and The wavelengths can constitute the first CWDM band; optical signal and The wavelength can constitute a second CWDM band; optical signal and The wavelength can constitute the third CWDM band; and the optical signal and The wavelengths can constitute a fourth CWDM band. In various examples, these CWDM bands can be CWMD-4 bands. In other examples, the band receiver 1400 can receive modulated optical signals of different numbers of CWDM bands (e.g., optical signals of two bands, three bands, five bands, etc.). Similarly, CWDM bands can include additional wavelengths (e.g., three wavelengths per CWDM band, four wavelengths per CWDM band, etc.).

[0167] exist Figures 2 to 12 In a specific example, band receiver 1400 receives modulated optical signals from four CWDM bands, where each CWDM band includes two wavelengths. In other words, band receiver 1400 can receive eight optical signals on a single input waveguide. Therefore, band receiver 1400 can be used in combination with... Figure 15 Any of the described band light sources and band transmitters can be used for operation. As a reminder above, each of these band light sources can generate optical signals of eight different wavelengths (including four CWDM bands, each with two wavelengths), and each of the band transmitters can modulate these eight wavelength optical signals.

[0168] Similar to band receiver 1300, band receiver 1400 can implement polarization diversity schemes.

[0169] Therefore, waveguide 1402 can be polarization-dependent. In other words, waveguide 1402 can have two modes. The first mode can be transverse electric (TE) mode. The modulated optical signal... to The vibrating electric field can partially activate this TE mode. This TE mode can have a known polarization state (e.g., a "horizontal" polarization state). The second mode can be a transverse magnetic (TM) mode. Modulated optical signal to The vibrating magnetic field can partially activate this TM mode. This TM mode can have a known polarization state (e.g., a "vertical" polarization state). As part of the polarization diversity scheme of the band receiver 1400, the two modes can be spatially split onto two separate waveguides.

[0170] Therefore, waveguide 1402 can modulate the optical signal to The signal is carried to polarization beamsplitter 1410. Polarization beamsplitter 1410 can carry the modulated optical signal... to The light beam is split into two separate beams. The first beam may include the TE mode (i.e., the "horizontal" polarization state) of the input beam and may continue to propagate along waveguide 1404 (which may have only a single TE mode). The second beam may include the TM mode (i.e., the "vertical" polarization state) of the input beam and may continue to propagate along waveguide 1406 (which may have only a single TM mode). The modulated optical signal of this first beam can be represented as a modulated optical signal. The modulated optical signal of this second beam can be represented as the modulated optical signal. to (Not depicted).

[0171] In some examples, waveguide 1406 can modulate optical signals. to The signal is carried to the polarization rotator 1420. Therefore, the polarization rotator 1420 can carry the modulated optical signal... to The polarization state is rotated by 90 degrees, causing the modulated optical signals to propagate in TE mode. The rotated modulated optical signal can be represented as... to It can also propagate along waveguide 1408 in TE mode.

[0172] After polarization beam splitting (and in some examples, polarization rotation), the modulated optical signal with known polarization can be carried to a band demultiplexer. Specifically, waveguide 1404 can carry the modulated optical signal... to The signal is carried to the band demultiplexer 1430, and the waveguide 1408 can carry the modulated optical signal. to Carry it to the band demultiplexer 1432.

[0173] Band demultiplexers 1430 and 1432 may be the same as / similar to the band demultiplexer described in conjunction with the previous figures. Therefore, band demultiplexer 1430 can modulate optical signals according to band splitting. to Specifically: modulated optical signals and It can be split onto waveguide 1440; the optical signal is modulated. and It can be split onto waveguide 1442; modulated optical signal and It can be split onto waveguide 1444; and the optical signal can be modulated. and It can be split onto waveguide 1446. In the same / similar manner, band demultiplexer 1432 can modulate the optical signal according to the band split. to Specifically: modulated optical signals and It can be split onto waveguide 1440; the optical signal is modulated. and It can be split onto waveguide 1442; modulated optical signal and It can be split onto waveguide 1444; and the optical signal can be modulated. and It can be split onto waveguide 1446.

[0174] As described above, after demultiplexing, each of waveguides 1440 to 1446 can carry a common CWDM band modulated optical signal. Specifically, waveguide 1440 can carry a first CWDM band modulated optical signal (i.e., a modulated optical signal...). and Waveguide 1442 can carry modulated optical signals in the second CWDM band (i.e., modulated optical signals). and Waveguide 1444 can carry modulated optical signals in the third CWDM band (i.e., modulated optical signals). and Furthermore, waveguide 1446 can carry modulated optical signals in the fourth CWDM band (i.e., modulated optical signals). and ).

[0175] Each waveguide adjacent to waveguides 1440 to 1446 may be two microring resonators. As mentioned above, a microring resonator can refer to a closed-loop waveguide that couples an input waveguide to an output waveguide. Here, the microring resonators couple waveguides 1440 to 1446 to waveguides including waveguide photodetectors 1460 to 1467. Specifically: microring resonator 1450 couples waveguide 1440 to a waveguide including waveguide photodetector 1460; microring resonator 1451 couples waveguide 1440 to a waveguide including waveguide photodetector 1461; microring resonator 1452 couples waveguide 1442 to a waveguide including waveguide photodetector 1462; microring resonator 1453 couples waveguide 1442 to a waveguide including waveguide photodetector 1463; microring resonator 1454 couples waveguide 1444 to a waveguide including waveguide photodetector 1464; microring resonator 1455 couples waveguide 1444 to a waveguide including waveguide photodetector 1465; microring resonator 1456 couples waveguide 1446 to a waveguide including waveguide photodetector 1466; and microring resonator 1457 couples waveguide 1446 to a waveguide including waveguide photodetector 1467. Similar to the other components mentioned above, these microring resonators can be constructed / obtained from readily available silicon photonics and III-V factory process design kits.

[0176] In the example of band receiver 1400, four microring resonators can be used as filters to divide optical signals of certain wavelengths. For example, microring resonators 1450 can be tuned to "divide" modulated optical signals of a first wavelength in a first CWDM band (e.g., modulated optical signals). and While allowing modulated optical signals of other wavelengths to pass through without interference, the microring resonator 1450 can simultaneously modulate optical signals... and The signal is distributed to the waveguide, including the waveguide photodetector 1460, while allowing the modulated optical signal to be transmitted. and Passing through undisturbed. In the same / similar manner, the microring resonator 1451 can modulate the optical signal... and The signal is distributed to the waveguide, including the waveguide photodetector 1461, while allowing the modulated optical signal to be transmitted. and Uninterrupted passage. Microring resonators 1452 to 1457 can be tuned in the same / similar manner such that the microring resonators "divide" one wavelength of modulated optical signal for each CWDM band, while allowing other wavelengths of modulated optical signal to pass through undisturbed.

[0177] Therefore, the waveguide photodetector 1460 can detect modulated optical signals. and The waveguide photodetector 1461 can detect modulated optical signals. and The waveguide photodetector 1462 can detect modulated optical signals. and The waveguide photodetector 1463 can detect modulated optical signals. and The waveguide photodetector 1464 can detect modulated optical signals. and The waveguide photodetector 1465 can detect modulated optical signals. and The waveguide photodetector 1466 can detect modulated optical signals. and Furthermore, the waveguide photodetector 1467 can detect modulated optical signals. and As described above, detecting the modulated optical signal can correspond to reading / extracting the data assigned to the modulated optical signal.

[0178] In some examples, the optical signal is modulated before being detected by waveguide photodetectors 1460 to 1467. to and modulated optical signal to One (or both) can be transmitted via phase shifters (PS) located on the same waveguides as waveguide photodetectors 1460 to 1467. These phase shifters can be used to account for any polarization mode dispersion in the optical fiber and the time delay caused by the modulated optical signal arriving at the waveguide photodetector via different paths (e.g., waveguide 1408 may be larger than waveguide 1404).

[0179] Similar to band receiver 1300, band receiver 1400 can also operate using existing CWDM / CWDM-4 technology. For example, band receiver 1400 can be configured using existing CWDM-4 technology by calibration / tuning to combine: waveguide photodetector 1460 to detect a modulated optical signal at a first CWDM-4 wavelength; waveguide photodetector 1462 to detect a modulated optical signal at a second CWDM-4 wavelength; waveguide photodetector 1464 to detect a modulated optical signal at a third CWDM-4 wavelength; and waveguide photodetector 1466 to detect a modulated optical signal at a fourth CWDM-4 wavelength. Similarly, other optical components of band receiver 1400 can be calibrated / tuned to operate with these CWDM-4 wavelengths. Therefore, band receiver 1400 can operate using existing CWDM-4 technology, as well as scaling techniques utilizing the CWDM bands disclosed herein.

[0180] Similar to the aforementioned band devices, the band receiver 1400 can be constructed using many off-the-shelf building blocks found in silicon photonics and III-V factory process design kits (e.g., broadband fiber-to-chip couplers, CWDM-4 waveguide photodetectors, etc.).

[0181] Figures 8 to 12 Another example band receiver is depicted, illustrating various examples of the technology according to this disclosure. Band receiver 1500 can be considered as a general-purpose band receiver from which band receivers 1300 and 1400 can be obtained.

[0182] The band receiver 1500 may include a first combination of one or more optical demultiplexers 1510, and at least a first optical photodetector 1520. These components may be connected via various waveguides. In some examples, the band receiver 1500 may also include a polarization beamsplitter 1530, a polarization rotator 1540, an optical phase shifter (not depicted), and other optical devices / components (e.g., a second combination of one or more optical demultiplexers 1512, a second optical photodetector 1522, etc.).

[0183] A first combination of one or more optical demultiplexers 1510 can split a first version of a modulated input beam into at least a first demultiplexed beam and a second demultiplexed beam.

[0184] The first version of the modulated input beam may include at least a first version (FMS) of the first modulated optical signal. 1 ) and the first version of the second modulated optical signal (SMS) 1 FMS 1 It can be the first wavelength within the first CWDM passband, and SMS 1 It can be a second wavelength within the first CWDM passband. As described above, the first CWDM passband can include a wavelength spectrum that includes CWDM wavelengths that can pass through an optical filter. In some examples, the first CWDM passband can include a first CWDM-4 wavelength.

[0185] FMS 1 It can be correlated with / obtained from the first modulated optical signal (FMS) in various ways. In some examples, the FMS... 1 It can be the same as FMS. In other examples, FMS 1 It can be either the transverse electric (TE) mode or the transverse magnetic (TM) mode of the FMS. In another example, the FMS... 1 It can be a TM mode of the FMS that has been rotated 90 degrees, causing the optical signal to propagate in TE mode. As mentioned above, the FMS can be a modulated version of the first optical signal (FS). The FS may have been modulated by combining... ​Modulation is performed on any of the described band transmitters.

[0186] SMS 1 It can be associated with SMS in the same / similar way.

[0187] The beam after the first demultiplexing can include at least FMS 1 As described above, a demultiplexed beam can refer to a beam that has been split by one or more optical demultiplexers. In various examples, the first demultiplexed beam may include additional modulated optical signals of different wavelengths. For example, in band receiver 1400 (which may be obtained from band receiver 1500), the first demultiplexed beam will also include a first version of a second modulated optical signal (i.e., SMS). 1 ).

[0188] The second demultiplexed beam can include wavelengths different from FMS. 1 At least a first version of a modulated optical signal. In some examples (e.g., band receiver 1300), the wavelength is different from FMS. 1 A first version of a modulated optical signal can be SMS 1 In other examples (e.g., band transmitter 1400), the wavelength differs from FMS. 1 A first version of a modulated optical signal may be a first version of a third modulated optical signal (not depicted). In some of these examples, the first version of the third modulated optical signal may be a first wavelength within the second CWDM passband.

[0189] The first optical photodetector (i.e., optical photodetector 1520) can detect FMS 1 To detect the beam after the first demultiplexing. An optical photodetector can refer to an optical device capable of detecting modulated optical signals. An optical photodetector can be calibrated to detect modulated optical signals of a specific wavelength. For example, an optical photodetector 1520 can be calibrated to detect FMS. 1 The modulated optical signal has a wavelength (i.e., the first wavelength within the first CWDM passband). The first optical photodetector 1520 can be of different types, including waveguide photodetectors.

[0190] As described above, the band receiver 1500 may include additional components. For example, the band receiver 1500 may include a polarization beamsplitter 1530. The polarization beamsplitter 1530 may split the modulated input beam into a first version of the modulated input beam and a second version of the modulated input beam. The second version of the modulated input beam may include at least a second version (FMS) of the first modulated optical signal. 2 ) and the second version of the modulated optical signal (SMS)2 ).

[0191] In some examples, a first version of the modulated input beam may be in TE mode, and a second version of the modulated input beam may be in TM mode. In some of these examples, the band receiver 1500 may include a polarization rotator 1540 that rotates the second version of the modulated input beam by 90 degrees, such that the second version of the modulated input beam also propagates in TE mode.

[0192] In an example where the band receiver 1500 splits a modulated input beam into a first and a second version of the modulated input beam, the band receiver 1500 may include a second combination of one or more optical demultiplexers 1512 that splits the second version of the modulated input beam into a third and a fourth demultiplexed beam.

[0193] The third demultiplexed beam can include at least FMS 2 In various examples, the third demultiplexed beam may include additional modulated optical signals of different wavelengths. For example, in band receiver 1400 (which may be obtained from band receiver 1500), the third demultiplexed beam will also include a second version of the second modulated optical signal (i.e., SMS). 2 ).

[0194] The fourth demultiplexed beam can include wavelengths different from FMS. 2 At least a second version of a modulated optical signal. In some examples (e.g., band receiver 1300), the wavelength is different from FMS. 2 A second version of a modulated optical signal can be SMS. 2 In other examples (e.g., band transmitter 1400), the wavelength differs from FMS. 2 A second version of a modulated optical signal can be a second version of a third modulated optical signal (not depicted). In some of these examples, the second version of the third modulated optical signal can be a first wavelength within the second CWDM passband.

[0195] The band receiver 1500 may also include additional optical photodetectors. For example, the band receiver 1500 may have a detection wavelength different from that of the FMS. 1 and FMS 2 A second optical photodetector 1522 for detecting modulated optical signals. For example, the second optical photodetector can be calibrated to detect modulated optical signals (e.g., SMS) of a second wavelength in the first CWDM passband. 1 and SMS 2), the first wavelength of the second CWDM passband, etc.

[0196] Similar to band receivers 1300 and 1400, band receiver 1500 can also operate using existing CWDM / CWDM-4 technologies. For example, band receiver 1500 can be combined using existing CWDM-4 technology by calibrating / tuning a first optical photodetector 1520 to detect modulated optical signals at a first CWDM-4 wavelength. Additional optical photodetectors that may be included in band receiver 1500 can also be calibrated to detect modulated optical signals at CWDM-4 wavelengths. Similarly, other optical components of band receiver 1500 (e.g., a combination of one or more demultiplexers) can be calibrated / tuned to operate with these CWDM-4 wavelengths. Therefore, band receiver 1500 can operate using existing CWDM-4 technology, as well as scaling techniques utilizing the CWDM bands disclosed herein.

[0197] Furthermore, similar to the aforementioned band devices, the band receiver 1500 can be constructed using many off-the-shelf building blocks found in silicon photonics and III-V factory process design kits (e.g., broadband fiber-to-chip couplers, CWDM-4 waveguide photodetectors, etc.).

[0198] As used herein, the term “or” can be interpreted in an inclusive or exclusive sense. Furthermore, descriptions of resources, operations, or structures in the singular form should not be construed as excluding the plural. Unless explicitly stated otherwise, or understood otherwise in the context in which they are used, conditional language (among others, such as “can,” “could,” “might,” or “may”) is generally intended to convey that certain examples include certain features, elements, and / or steps while others do not.

[0199] Unless otherwise explicitly stated, the terms and phrases used in this document, and their variations thereof, should be interpreted as open-ended rather than restrictive. Adjectives (such as “conventional,” “traditional,” “normal,” “standard,” “known,” and similar terms) should not be interpreted as limiting the described items to items available for a given period of time or at a given time, but should be understood to encompass conventional, traditional, normal, or standard techniques that may be available or known at any time now or in the future. In some cases, the presence of broad words and phrases (such as “one or more,” “at least,” “but not limited to,” or other similar phrases) should not be interpreted as indicating an intention or requirement for a narrower situation where such broad phrases may not exist.

Claims

1. A light source having a first mode and a second mode, the light source comprising: at least a first laser array, wherein: in the first mode, the first laser array emits optical signals of only a first wavelength within a first coarse wavelength division multiplexing CWDM passband, wherein the first coarse wavelength division multiplexing CWDM passband is a wavelength spectrum including first CWDM wavelengths; and in the second mode, the first laser array emits optical signals of at least the first wavelength within the first coarse wavelength division multiplexing CWDM passband and a second wavelength within the first coarse wavelength division multiplexing CWDM passband.

2. The light source of claim 1, further comprising a second laser array, a third laser array, and a fourth laser array, wherein: in the second mode: the second laser array emits optical signals of at least a first wavelength and a second wavelength within a second coarse wavelength division multiplexing CWDM passband, wherein the second coarse wavelength division multiplexing CWDM passband is a wavelength spectrum including second CWDM wavelengths, the third laser array emits optical signals of at least a first wavelength and a second wavelength within a third coarse wavelength division multiplexing CWDM passband, wherein the third coarse wavelength division multiplexing CWDM passband is a wavelength spectrum including third CWDM wavelengths, and the fourth laser array emits optical signals of at least a first wavelength and a second wavelength within a fourth coarse wavelength division multiplexing CWDM passband, wherein the fourth coarse wavelength division multiplexing CWDM passband is a wavelength spectrum including fourth CWDM wavelengths, and in the first mode: the second laser array emits optical signals of only a first wavelength within the second coarse wavelength division multiplexing CWDM passband, the third laser array emits optical signals of only a first wavelength within the third coarse wavelength division multiplexing CWDM passband, and the fourth laser array emits optical signals of only a first wavelength within the fourth coarse wavelength division multiplexing CWDM passband.

3. The light source of claim 2, wherein: the first CWDM wavelength is a first CWDM-4 wavelength; the second CWDM wavelength is a second CWDM-4 wavelength; the third CWDM wavelength is a third CWDM-4 wavelength; and the fourth CWDM wavelength is a fourth CWDM-4 wavelength.

4. The light source of claim 2, wherein: the first wavelength within the first coarse wavelength division multiplexing CWDM passband is a first CWDM-4 wavelength; the first wavelength within the second coarse wavelength division multiplexing CWDM passband is a second CWDM-4 wavelength; the first wavelength within the third coarse wavelength division multiplexing CWDM passband is a third CWDM-4 wavelength; and the first wavelength within the fourth coarse wavelength division multiplexing CWDM passband is a fourth CWDM-4 wavelength.

5. The light source of claim 1, further comprising an optical coupler, wherein, in the second mode, the optical coupler: receives a first optical signal from a first input waveguide, wherein the first optical signal is a first wavelength within the first coarse wavelength division multiplexing CWDM passband; receives a second optical signal from a second input waveguide, wherein the second optical signal is a second wavelength within the first coarse wavelength division multiplexing CWDM passband; and combining a version of the first optical signal with a version of the second optical signal onto a first output waveguide.

6. The optical source of claim 5, wherein: the version of the first optical signal is a first power-reduced version of the first optical signal; and the optical coupler: splits the first power-reduced version of the first optical signal onto the first output waveguide; and splits a second power-reduced version of the first optical signal onto a second output waveguide.

7. The optical source of claim 5, wherein the optical coupler comprises a star coupler.

8. The light source of claim 7, wherein, the star coupler comprises one or more multimode interference devices.

9. An optical source having a first mode and a second mode, the optical source comprising: at least a first laser array, wherein: in the first mode, the first laser array emits an optical signal of only a first wavelength within a first coarse wavelength division multiplexing CWDM passband, wherein the first coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a first CWDM wavelength; and in the second mode, the first laser array emits an optical signal of at least the first wavelength within the first coarse wavelength division multiplexing CWDM passband and a second wavelength within the first coarse wavelength division multiplexing CWDM passband; and an optical coupler, wherein, in the second mode, the optical coupler: receives a first optical signal from a first input waveguide, wherein the first optical signal is the first wavelength within the first coarse wavelength division multiplexing CWDM passband; receives a second optical signal from a second input waveguide, wherein the second optical signal is the second wavelength within the first coarse wavelength division multiplexing CWDM passband; and combines a version of the first optical signal with a version of the second optical signal onto a first output waveguide.

10. The optical source of claim 9, further comprising a second laser array, a third laser array, and a fourth laser array, wherein: in the second mode: the second laser array emits an optical signal of at least the first wavelength and the second wavelength within a second coarse wavelength division multiplexing CWDM passband, wherein the second coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a second CWDM wavelength, the third laser array emits an optical signal of at least the first wavelength and the second wavelength within a third coarse wavelength division multiplexing CWDM passband, wherein the third coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a third CWDM wavelength, and the fourth laser array emits an optical signal of at least the first wavelength and the second wavelength within a fourth coarse wavelength division multiplexing CWDM passband, wherein the fourth coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a fourth CWDM wavelength, and in the first mode: the second laser array emits an optical signal of only the first wavelength within the second coarse wavelength division multiplexing CWDM passband, the third laser array emits an optical signal of only the first wavelength within the third coarse wavelength division multiplexing CWDM passband, and the fourth laser array emits an optical signal of only the first wavelength within the fourth coarse wavelength division multiplexing CWDM passband.

11. The optical source of claim 10, wherein: the first CWDM wavelength is a first CWDM-4 wavelength; the second CWDM wavelength is a second CWDM-4 wavelength; the third CWDM wavelength is a third CWDM-4 wavelength; and the fourth CWDM wavelength is a fourth CWDM-4 wavelength.

12. The optical source of claim 10, wherein: the first wavelength within the first coarse wavelength division multiplexing CWDM passband is a first CWDM-4 wavelength; the first wavelength within the second coarse wavelength division multiplexing CWDM passband is a second CWDM-4 wavelength; the first wavelength within the third coarse wavelength division multiplexing CWDM passband is a third CWDM-4 wavelength; and the first wavelength within the fourth coarse wavelength division multiplexing CWDM passband is a fourth CWDM-4 wavelength.

13. The optical source of claim 9, wherein the optical coupler comprises one or more of a star coupler or a multimode interference device.

14. The optical source of claim 9, wherein: the version of the first optical signal is a first power-reduced version of the first optical signal; and the optical coupler: splits the first power-reduced version of the first optical signal onto the first output waveguide; and splits a second power-reduced version of the first optical signal onto a second output waveguide.

15. A method comprising: in a first mode of an optical source, emitting, by a first laser array, an optical signal of only a first wavelength within a first coarse wavelength division multiplexing CWDM passband, wherein the first coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a first CWDM wavelength; and in a second mode of the optical source, emitting, by the first laser array, an optical signal of at least the first wavelength within the first coarse wavelength division multiplexing CWDM passband and a second wavelength within the first coarse wavelength division multiplexing CWDM passband.

16. The method of claim 15, wherein the optical source comprises a second laser array, a third laser array, and a fourth laser array, wherein: in the second mode: emitting, by the second laser array, an optical signal of at least the first wavelength and the second wavelength within a second coarse wavelength division multiplexing CWDM passband, wherein the second coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a second CWDM wavelength, emitting, by the third laser array, an optical signal of at least the first wavelength and the second wavelength within a third coarse wavelength division multiplexing CWDM passband, wherein the third coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a third CWDM wavelength, and emitting, by the fourth laser array, an optical signal of at least the first wavelength and the second wavelength within a fourth coarse wavelength division multiplexing CWDM passband, wherein the fourth coarse wavelength division multiplexing CWDM passband is a spectrum of wavelengths including a fourth CWDM wavelength, and in the first mode: emitting, by the second laser array, an optical signal of only the first wavelength within the second coarse wavelength division multiplexing CWDM passband, emitting, by the third laser array, an optical signal of only the first wavelength within the third coarse wavelength division multiplexing CWDM passband, and emitting, by the fourth laser array, an optical signal of only the first wavelength within the fourth coarse wavelength division multiplexing CWDM passband.

17. The method of claim 16, wherein: the first CWDM wavelength is a first CWDM-4 wavelength; the second CWDM wavelength is a second CWDM-4 wavelength; the third CWDM wavelength is a third CWDM-4 wavelength; and the fourth CWDM wavelength is a fourth CWDM-4 wavelength.

18. The method of claim 16, wherein: the first wavelength within the first coarse wavelength division multiplexing, CWDM, passband is a first CWDM-4 wavelength; the first wavelength within the second coarse wavelength division multiplexing, CWDM, passband is a second CWDM-4 wavelength; the first wavelength within the third coarse wavelength division multiplexing, CWDM, passband is a third CWDM-4 wavelength; and the first wavelength within the fourth coarse wavelength division multiplexing, CWDM, passband is a fourth CWDM-4 wavelength.

19. The method of claim 15, wherein the optical source comprises an optical coupler, wherein the method comprises, in the second mode, receiving a first optical signal from a first input waveguide by the optical coupler, wherein, the first optical signal is a first wavelength within the first coarse wavelength division multiplexing, CWDM, passband; receiving, by the optical coupler, a second optical signal from a second input waveguide, wherein the second optical signal is a second wavelength within the first coarse wavelength division multiplexing, CWDM, passband; and combining a version of the first optical signal and a version of the second optical signal onto a first output waveguide.

20. The method of claim 19, wherein: the version of the first optical signal is a first power reduced version of the first optical signal; and the method comprises: splitting, by the optical coupler, the first power reduced version of the first optical signal onto the first output waveguide; and splitting, by the optical coupler, a second power reduced version of the first optical signal onto a second output waveguide.

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