Switching engine assisted optical channel monitor

Abstract

The invention relates to an optical channel monitor assisted by a switching engine. Some embodiments relate to an optical channel monitor. The optical channel monitor may include a dispersive element positioned in an optical path of the optical signal, the dispersive element separating the optical signal into dispersive wavelength channels. An optical channel monitor may include a switching engine positioned in an optical path of a dispersive wavelength channel to direct one or more wavelength channel subsets of an optical signal. The optical channel monitor may include a tunable filter to scan respective wavelength channels through a subset of one or more wavelength channels of the optical signal.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 561,501, filed on March 5, 2024, and entitled “Switch Engine Assisted Silicon Photonics Optical Channel Monitor.” The disclosure of that prior application is considered a part of and incorporated by reference into this patent application. Technical Field

[0003] The present disclosure relates generally to optical networks and optical channel monitors facilitated by switching engines. Background Art

[0004] An optical channel monitor (OCM) is a device capable of measuring the optical power in a wavelength channel of an optical signal. An OCM can be connected to a point in an optical network to measure, for example, the power, frequency, and other characteristics of the optical channel at that point. In some cases, the OCM can scan multiple wavelength channels to measure the optical power in multiple channels (e.g., across a range of wavelengths). For example, an OCM can be used to monitor channels in a wavelength division multiplexing (WDM) system in which wavelength channels are multiplexed into a common carrier signal for transmission over an optical network (e.g., a dense wavelength division multiplexing (DWDM) system in which wavelength channels are spaced apart at frequencies of 50 gigahertz (GHz), among other examples). Summary of the Invention

[0005] Some embodiments relate to an optical device that combines a wavelength selective switch and an optical channel monitor. The optical device may include a first port group for wavelength division switching, the first port group including a first input port for transmitting a first optical signal. The optical device may include a second port group for optical channel monitoring, the second port group including a second input port for transmitting a second optical signal. The optical device may include a dispersive element positioned in the optical paths of the first and second optical signals, the dispersive element separating the first and second optical signals into dispersed wavelength channels. The optical device may include a switching engine positioned in the optical paths of the dispersed wavelength channels, the switching engine directing one or more wavelength channels of the first optical signal to corresponding output ports of the first port group, and directing one or more wavelength channel subsets of the second optical signal to output ports of the second port group. The optical device may include a tunable filter for scanning through corresponding wavelength channels of the one or more wavelength channel subsets of the second optical signal.

[0006] Some embodiments relate to an optical channel monitor. The optical channel monitor may include a dispersive element positioned in an optical path of an optical signal, the dispersive element separating the optical signal into dispersive wavelength channels. The optical channel monitor may include a switching engine positioned in the optical path of the dispersive wavelength channels, the switching engine configured to direct one or more wavelength-channel subsets of the optical signal. The optical channel monitor may include a tunable filter configured to scan corresponding wavelength channels of the one or more wavelength-channel subsets of the optical signal.

[0007] In some embodiments, a method includes directing, by a switching engine of an optical device, one or more wavelength-channel subsets of an optical signal to a tunable filter of the optical device, and scanning, by the tunable filter, respective wavelength-channels of the one or more wavelength-channel subsets of the optical signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram illustrating an example of an optical device.

[0009] Figure 2 is a schematic diagram illustrating an example of an optical device.

[0010] Figure 3A is a schematic diagram illustrating an example optical system that may be used in an optical device.

[0011] Figures 3B to 3D is a schematic diagram illustrating an example tunable filter.

[0012] Figure 4 is a schematic diagram illustrating an example ring filter.

[0013] Figure 5 is a flow chart of an example process associated with optical channel monitoring. DETAILED DESCRIPTION

[0014] The following detailed description of example embodiments refers to the accompanying drawings, in which the same reference numerals in different drawings may identify the same or similar elements.

[0015] An optical channel monitor (OCM) can be used in an optical network to measure characteristics associated with wavelength channels used in the optical network. An OCM equipped to handle fast and efficient monitoring of multiple wavelength channels can have a complex design and, therefore, can be expensive. In some examples, the OCM can be combined with a wavelength selective switch (WSS) to provide fast scanning through wavelength channels using a switching engine. The scanning speed of the OCM can depend on the switching speed of the switching engine. However, simple switching engines are generally associated with switching speeds that are insufficient to support the OCM, while a switching engine with switching speeds sufficient to support the OCM may add additional complexity and be costly.

[0016] Some embodiments described herein relate to optical devices that combine WSS and OCM. In some embodiments, the optical device includes a switching engine and a tunable filter. The switching engine can sequentially direct multiple filtered dispersed wavelength channel subsets of an optical signal to the tunable filter. For example, a first subset can include a first interleaved spectrum (e.g., having odd-numbered wavelength channels), and a second subset can include a second interleaved spectrum (e.g., having even-numbered wavelength channels). The tunable filter can scan through the corresponding wavelength channels of each filtered wavelength channel subset and can measure the corresponding wavelength channels in conjunction with optical channel monitoring.

[0017] A switching engine may be capable of filtering wavelength channels with high precision, but the switching speed may be relatively slow. Therefore, various low-complexity and low-cost switching engines may be used in optical devices. In contrast, a tunable filter may be associated with fast switching speeds, but may have relatively low filtering precision compared to a switching engine. Therefore, a tunable filter may also be associated with low complexity and low cost. For example, the tunable filter may be a silicon photonics (SiP) filter. The switching engine may be used to accurately pre-filter the total spectrum into several filtered spectra, where the spacing between the wavelength channels is suitable for fast scanning of the tunable filter without requiring high precision (e.g., due to the spacing between the wavelength channels). Therefore, combining the precise filtering of the switching engine with the high-speed scanning of the tunable filter enables accurate, fast, and low-cost OCM.

[0018] Figure 1 is a schematic diagram illustrating an example of an optical device 100. The optical device 100 includes a WSS and / or an OCM. For example, the optical device 100 implements a combination of the WSS and the OCM. As shown, the optical device 100 may include a first port group 102, a second port group 104, a dispersive element 106, a switching engine 108, a tunable filter 110, and / or a monitoring element 112.

[0019] The first port group 102 can be used for wavelength division switching (WDS). For example, the first port group 102 can be used for WSS of the optical device 100. Therefore, the first port group 102 can be referred to herein as "WSS port group 102," and the ports of the first port group 102 can be referred to herein as "WSS ports." The second port group 104 can be used for optical channel monitoring. Therefore, the second port group 104 can be referred to herein as "OCM port group 104," and the ports of the second port group 104 can be referred to herein as "OCM ports." The WSS port group 102 (e.g., for WSS operation of the optical device 100) and the OCM port group 104 (e.g., for OCM operation of the optical device 100) can use corresponding optical paths (e.g., dual paths) of the optical device 100, but can share the same optical system (e.g., dispersive element 106 and switching engine 108) of the optical device 100. Alternatively, the WSS port group 102 and the OCM port group 104 can use corresponding optical systems (e.g., corresponding dispersive element and switching engine groups). The WSS port group 102 and the OCM port group 104 may be included in the same port array (eg, the same physical unit) or in respective port arrays.

[0020] The WSS port group 102 may include a WSS input port 102a and a plurality of WSS output ports 102b, shown as WSS output ports 1 to N, where N is an integer greater than or equal to 2. Similarly, the OCM port group 104 may include an OCM input port 104a and an OCM output port 104b. In some embodiments, the OCM input port 104a may be one of the plurality of OCM input ports 104a of the OCM port group 104, such as in conjunction with Figure 2 In some embodiments, the WSS ports 102a, 102b of the WSS port group 102 and the OCM ports 104a, 104b of the OCM port group 104 are optically coupled to optical fibers and / or waveguides (not shown). For example, the WSS input port 102a and the OCM input port 104a can be optically coupled to corresponding input optical fibers, and the WSS output port 102b and the OCM output port 104b can be optically coupled to corresponding output optical fibers.

[0021] The WSS input port 102a can transmit a first optical signal (e.g., a signal carried by an input optical fiber) into the optical system of the optical device 100. The first optical signal may be referred to herein as a "WSS optical signal." Similarly, the OCM input port 104a can transmit a second optical signal (e.g., carried by an input optical fiber) into the optical system of the optical device 100. The second optical signal may be referred to herein as an "OCM optical signal." The WSS optical signal and the OCM optical signal may each be a wavelength division multiplexed signal. The WSS optical signal and the OCM optical signal may be separated from the same original signal, or the WSS optical signal and the OCM optical signal may be different signals.

[0022] The dispersive element 106 may include an element that separates a light beam into dispersed wavelength channel beamlets and combines (e.g., converges) the dispersed wavelength channel beamlets based on wavelength. Specifically, in the forward direction of light propagation, the dispersive element 106 can separate (e.g., spread or angularly diverge) a light beam (e.g., an input light beam emitted by the WSS input port 102a or the OCM input port 104a) into multiple beamlets, each beamlet carrying a wavelength channel of the light beam, the wavelength channel comprising one or more wavelengths within a specific wavelength range. In the reverse direction of light propagation, the dispersive element 106 can combine (e.g., angularly converge) the multiple groups of dispersed wavelength channel beamlets to form a wavelength division multiplexed signal (e.g., each signal comprising one or more dispersed wavelength channel beamlets). In some embodiments, the dispersive element 106 may include a diffractive optical device. The dispersive element 106 may include a diffraction grating, a prism, an echelle grating, a grism, or the like.

[0023] The WSS input port 102a can transmit the WSS optical signal into the dispersive element 106, and the OCM input port 104a can transmit the OCM optical signal into the dispersive element 106. For example, the dispersive element 106 can be positioned in the optical path of the WSS optical signal and the OCM optical signal. The dispersive element 106 can separate the WSS optical signal and the OCM optical signal into wavelength channels (e.g., sub-beams). In other words, the dispersive element 106 can separate the WSS optical signal into a first plurality of wavelength channels and separate the OCM optical signal into a second plurality of wavelength channels.

[0024] The switching engine 108 may include a switching array of switching elements for independent routing of dispersive wavelength channels. Each dispersive wavelength channel may be incident on a different switching element of the switching engine 108. Each switching element of the switching engine 108 may manipulate (e.g., based on the angle of the switching element) a corresponding dispersive wavelength channel. The switching engine 108 may include a digital light processor (DLP) switching engine (e.g., using a digital micromirror device), a liquid crystal on silicon (LCOS) switching engine, a microelectromechanical system (MEMS) mirror switching engine (e.g., using a tiltable MEMS mirror array), or a stack of liquid crystal cells and birefringent prisms, among others.

[0025] The switching engine 108 can be positioned in the optical path of the dispersive wavelength channels of the dispersive element 106. The switching engine 108 can direct (e.g., steer) the wavelength channels of the WSS optical signal to corresponding WSS output ports 102b (e.g., one wavelength channel per WSS output port 102b or multiple wavelength channels per WSS output port 102b). In addition, the switching engine 108 can direct (e.g., steer) one or more subsets of the wavelength channels (e.g., an appropriate subset) of the OCM optical signal to the tunable filter 110 via the OCM output port 104b. For example, the switching engine 108 can direct the subset of wavelength channels (e.g., a filtered optical spectrum) to the tunable filter 110 (e.g., via the OCM output port 104b) while blocking (e.g., transmitting or absorbing rather than reflecting, reflecting elsewhere, etc.) the remaining wavelength channels. The wavelength channel subsets may include any number of wavelength channels that are less than all of the dispersed wavelength channels (e.g., a subdivision of the entire optical spectrum); however, in some examples, the switching engine 108 may direct a set of all wavelength channels of the OCM optical signal to the tunable filter 110 (e.g., to facilitate measurement of total optical power, or measurement of light present at boundaries between wavelength channels).

[0026] To achieve this blocking, and also to facilitate monitoring of all dispersed wavelength channels of the OCM optical signal, the switching engine 108 may sequentially change the optical spectrum directed to the tunable filter 110 (e.g., via the OCM output port 104b). For example, the total dispersed wavelength channels may be subdivided into a plurality of wavelength channel subsets (e.g., wherein each subset has fewer than all dispersed wavelength channels). Each wavelength channel subset may be different from any other wavelength channel subset (e.g., differing by at least one wavelength channel). For example, each wavelength channel subset may have no common wavelength channels with any other wavelength channel subset (e.g., the wavelength channel subsets may be different subdivisions of the entire optical spectrum, which may depend on the mode or configuration). For example, a combination of multiple wavelength channel subsets may include all dispersed wavelength channels (e.g., the entire optical spectrum).

[0027] As an example, the switching engine 108 can direct a first subset of wavelength channels (e.g., the first spectrum) to the tunable filter 110 (e.g., via the OCM output port 104b) while blocking a second subset of wavelength channels (e.g., the second spectrum). Continuing with this example, after directing the first subset of wavelength channels, the switching engine 108 can direct the second subset of wavelength channels to the tunable filter 110 (e.g., via the OCM output port 104b) while blocking the first subset of wavelength channels. This sequential directing can be performed using any number of wavelength channel subsets.

[0028] In some embodiments, the wavelength channel subsets may include a pattern or configuration of wavelength channels based on one or more characteristics of the tunable filter 110 (e.g., the accuracy of the tunable filter 110, the switching speed of the tunable filter 110, etc.). In some embodiments, the wavelength channel subsets may have spacing between each wavelength channel included in the subset. For example, multiple wavelength channel subsets may include two or more interleaved spectrums to reduce adjacent channel crosstalk at the tunable filter 110. As an example, the switching engine 108 may direct a first interleaved spectrum (e.g., having odd-numbered wavelength channels) to the tunable filter 110 while blocking a second interleaved spectrum (e.g., having even-numbered wavelength channels). Continuing with this example, the switching engine 108 may then direct the second interleaved spectrum to the tunable filter 110 while blocking the first interleaved spectrum. An interleaved spectrum may include wavelength channels that alternate with wavelength channels of another interleaved spectrum in the frequency domain. In this manner, the switching engine 108 provides pre-filtering of dispersive wavelength channels prior to filtering by the tunable filter 110.

[0029] The tunable filter 110 can be optically coupled to the OCM output port 104b (eg, via an optical fiber). In some embodiments, the tunable filter 110 can be in the optical path of the subset of wavelength channels directed by the switching engine 108, such as in conjunction with Figure 3A The tunable filter 110 can provide filtering for wavelength channels directed to the tunable filter 110 (e.g., via the OCM output port 104b). For example, the tunable filter 110 can filter a particular wavelength channel while allowing one or more other wavelength channels to pass through. In addition, the wavelength channels filtered and passed by the tunable filter 110 can be dynamically controlled (e.g., by thermal tuning). The tunable filter 110 can be a SiP filter. In some embodiments, the SiP filter can be a ring filter, such as a filter incorporating Figure 4 Described Vernier ring filter.

[0030] The tunable filter 110 may scan through or swap (e.g., one at a time) respective wavelength channels of a subset (one or more) of wavelength channels directed to the tunable filter 110 (e.g., via the OCM output port 104b). For example, the tunable filter 110 may scan through respective wavelength channels of a first subset (e.g., a first spectrum) of wavelength channels directed to the tunable filter 110, and subsequently, after scanning through the first subset of wavelength channels, the tunable filter 110 may scan through respective wavelength channels of a second subset of wavelength channels directed to the tunable filter 110. "Scanning" through the wavelength channels may mean passing the first wavelength channel and filtering the other wavelength channels during a first time period, passing the second wavelength channel and filtering the other wavelength channels during a second subsequent time period, and so on.

[0031] While switching engine 108 may be capable of filtering wavelength channels with high precision, switching engine 108 may have a relatively slow switching speed (e.g., and therefore may be relatively low-cost and relatively uncomplicated). Consequently, switching engine 108 may be unable to scan through all dispersive wavelength channels within the allotted time (e.g., less than 1 second). For example, the update rate of switching engine 108 may be 60 Hz or lower. In contrast, tunable filter 110 may be associated with a fast switching speed (e.g., associated with an update time in the microsecond range), but may have a relatively lower filtering precision than switching engine 108 (e.g., and therefore may be relatively low-cost and relatively uncomplicated). Thus, switching engine 108 may be used to accurately pre-filter the total spectrum into a filtered spectrum that is suitable for rapid scanning by tunable filter 110 without requiring high precision. Thus, combining the precise filtering of switching engine 108 with the high-speed scanning of tunable filter 110 enables accurate, fast, and low-cost OCM.

[0032] During the allotted scan time, the switching engine 108 can generate M filtered spectra, where M is greater than or equal to 2 (e.g., where the upper limit of M is a function of the switching speed of the switching engine 108 and the allotted scan time). For example, as described above, the switching engine 108 can generate two interleaved spectra (M=2) during the allotted time. However, if the switching engine 108 has an update rate of 60 Hz, then during the allotted scan time of 500 milliseconds (ms), the switching engine 108 can generate up to 30 subdivided spectra (M=30). The tunable filter 110 can scan through the spectra (or through relevant portions of the spectra) during the time between spectral updates by the switching engine 108. For example, for two spectra (M=2) and an allotted scan time of 500 ms, the tunable filter 110 has 250 ms to scan each spectrum. As another example, for 30 spectra (M=30) and an allotted scan time of 500 ms, the tunable filter 110 has approximately 16 ms to scan each spectrum.

[0033] The monitoring element 112 may include one or more photodetectors 114 (e.g., photodiodes, etc.) and a signal processing unit 116. The signal processing unit 116 may include one or more analog-to-digital converters (ADCs) and / or digital signal processors, etc. The monitoring element 112 may monitor the corresponding wavelength channels output by the tunable filter 110. For example, the monitoring element 112 may detect each wavelength channel output by the tunable filter 110, convert the wavelength channel into an electrical signal, and / or convert the electrical signal into a digital signal, etc. The output of the monitoring element 112 may be provided to an analysis component (e.g., a computing device, a processor, etc.), which is configured to measure the characteristics of each wavelength channel based on the output. In some embodiments, the tunable filter 110 and / or the monitoring element 112 may be integrated into a SiP chip.

[0034] As mentioned above, Figure 1 Provided as an example. Other examples may differ from the Figure 1 described.

[0035] Figure 2 is a schematic diagram illustrating an example of the optical device 100 . Figure 2 An example is Figure 1 A modified embodiment of the optical device 100 described in Figure 2 As shown, the OCM port group 104 may include a plurality of OCM input ports 104a, shown as OCM input ports 1 through N, where N is an integer greater than or equal to 2. Each OCM input port 104a may be tapped to a corresponding location in the optical network, thereby facilitating monitoring of different locations in the optical network.

[0036] As described herein, each OCM input port 104a can transmit an OCM optical signal. The switching engine 108 can sequentially direct the filtered wavelength-channel subset of each OCM optical signal. For example, the switching engine 108 can direct the filtered wavelength-channel subset of a first OCM optical signal from the first OCM input port 104a to the OCM output port 104b, then the switching engine 108 can direct the filtered wavelength-channel subset of a second OCM optical signal from the second OCM input port 104a to the OCM output port 104b, and so on. In this manner, the switching engine 108 can operate as a port switch to scan multiple separate optical spectra.

[0037] As mentioned above, Figure 2 Provided as an example. Other examples may differ from the Figure 2 described.

[0038] Figure 3A FIG2 is a schematic diagram illustrating an example optical system 300 that can be used in an optical device, such as the optical device 100. The optical system 300 can include a polarization beam splitter 302 and a polarization rotator 304. The optical system 300 can be positioned in the optical path of an OCM optical signal emitted from the OCM input port 104 a. For example, the polarization beam splitter 302 and the polarization rotator 304 can be positioned between the OCM input port 104 a and the dispersive element 106.

[0039] As shown, the OCM optical signal emitted from OCM input port 104a can have different polarizations. Generally speaking, SiP devices do not propagate transverse magnetic (TM) mode light well, thus affecting polarization diversity in OCM. Furthermore, some types of switching engines, such as those using liquid crystals, may only operate on one polarization. However, many applications may require monitoring both the transverse electric (TE) polarization and the TM polarization of the OCM optical signal.

[0040] The polarization beam splitter 302 can separate the OCM optical signal into a first signal having a first polarization (e.g., TM polarization or one of the TM polarizations) and a second signal having a second polarization (e.g., TM polarization or the other of the TM polarizations). The polarization rotator 304 can rotate the polarization of the first signal or the second signal. For example, the polarization rotator 304 can rotate the polarization of the first signal or the second signal so that the first signal and the second signal have the same polarization (e.g., TM polarization). The first signal and the second signal can pass through the dispersive element 106 (e.g., to generate a dispersive wavelength channel) and propagate in corresponding paths to the switching engine 108, and the first signal and the second signal can be imaged onto the tunable filter 110, respectively.

[0041] The tunable filter 110 may include a first tunable filter component 110-1 (e.g., a first tunable filter) and a second tunable filter component 110-2 (e.g., a second tunable filter). In addition, the tunable filter 110 may include a first surface coupler 111-1 for (e.g., coupled to) the first tunable filter component 110-1 and a second surface coupler 111-2 for (e.g., coupled to) the second tunable filter component 110-2. The switching engine 108 may transmit the filtered wavelength channel subset of the first signal (in combination with the first surface coupler 111-1) to the first surface coupler 111-1. Figure 1 1 and 110-2. The first tunable filter component 110-1 can be configured to direct the two polarizations directly to the first surface coupler 111-1 and the second surface coupler 111-2. Figure 3A The example utilizes polarization separation, which enables the switching engine 108 to operate on two polarizations, thereby eliminating the additional steps of recombining the polarizations and then separating the polarizations again for the tunable filter 110.

[0042] The first tunable filter component 110-1 may scan through corresponding wavelength channels of the filtered subset of wavelength channels of the first signal, and the second tunable filter component 110-2 may scan through corresponding wavelength channels of the filtered subset of wavelength channels of the second signal (e.g., individually). Figure 3A (not shown) can be combined Figure 1 The respective wavelength channels output by each of the first and second tunable filter components 110-1, 110-2 can be monitored in a similar manner as described. In some embodiments, the first and second polarizations can be recombined in the digital domain (eg, at one or more monitoring elements 112).

[0043] As mentioned above, Figure 3A Provided as an example. Other examples may differ from the Figure 3A described.

[0044] Figures 3B to 3D is a schematic diagram illustrating an example tunable filter 110 . Figures 3B to 3D The tunable filter 110 includes polarization separation and rotation functionality (e.g., on a chip) rather than in the optical system 300, such as in combination with Figure 3A As stated.

[0045] Figure 3B FIG. 1 shows a tunable filter 110 in an edge-coupled configuration. Figure 3B As shown, light from the switching engine 108 (e.g., from the free-space portion) can be coupled directly into the tunable filter 110 (e.g., into a tunable filter chip) via a lens or an optical fiber, which is coupled to the tunable filter 110. The tunable filter 110 can include a polarization beam splitter 302 and a polarization rotator 304. In this way, the first tunable filter component 110-1 and the second tunable filter component 110-2 can use only a single polarization state.

[0046] Figure 3C The tunable filter 110 is shown in a surface grating coupler configuration. The surface grating 306 can diffract and focus a light beam incident on the top surface of the tunable filter 110 (e.g., a tunable filter chip) into a single-mode waveguide. Due to the geometry, only light initially polarized perpendicular to the output waveguide will be diffracted. Thus, the single grating 306 acts as a polarizer. A second grating 306, arranged orthogonally to the first grating 306 and positioned in the beam spot, couples the opposite polarization to the first grating 306.

[0047] Figure 3D FIG. 1 shows a tunable filter 110 in a dual polarization grating configuration. Figure 3D As shown, the gratings 306 can overlap each other to form a two-dimensional grating. In this way, the coupling efficiency is improved by positioning each grating 306 at the center of the beam spot.

[0048] As mentioned above, Figures 3B to 3D Provided as an example. Other examples may differ from the Figures 3B to 3D described.

[0049] Figure 4 is a schematic diagram illustrating an example loop filter 400. The loop filter 400 may correspond to the tunable filter 110 and / or the tunable filter components 110-1, 110-2. The loop filter 400 may be a Vernier loop filter.

[0050] As shown, the ring filter 400 may include an input 402 and an output 404 that define a direction of light propagation. The ring filter 400 may include a first band-selective Mach-Zehnder interferometer 406 and a second band-selective Mach-Zehnder interferometer 408 coupled to the output of the first band-selective Mach-Zehnder interferometer 406. In addition, the ring filter 400 may include a first Vernier ring 410 coupled to the output of the second band-selective Mach-Zehnder interferometer 408, and a second Vernier ring 412 coupled to the output of the first Vernier ring 410. The ring filter 400 may include one or more heating elements (not shown) configured to heat the Vernier rings 410, 412 to different temperatures, thereby changing the wavelengths filtered by the Vernier rings 410, 412.

[0051] In some embodiments, the tunable filter 110 can include a series of Mach-Zehnder interferometers, each with a delay arm of a different length, which together form a bandpass filter. Tuning can be performed using heating elements on the delay arms. In some embodiments, the tunable filter 110 can include a ring coupled to the input and output bus waveguides, which provides a narrow bandpass filter. Tuning can be performed using heating elements on the ring segments. The filter can be periodic in optical frequency, with a period F of the free spectral range (FSR). A single ring can be used if the FSR is wide enough so that the free-space wavelength selection elements (e.g., the dispersive element 106 and the switching engine 108) can remove unwanted wavelengths from the current scan region. Sharper filtering can be achieved by using multiple (e.g., two) rings to create a higher-order filter. The FSRs of the two rings can be offset by a small amount, F2 = F1 – df, thereby increasing the effective FSR to F1 × F2 / df (Vernier effect). This relaxes the pre-filtering requirements for free-space wavelength selection. In some embodiments, two or more ring filters with different FSRs can be placed in series (e.g., cascaded rings) to narrow the passband and increase the overall FSR through the Vernier effect. The ring filters can be single-ring filters or multi-ring filters connected in series. In some embodiments, the tunable filter 110 can employ a combination of a Mach-Zehnder interferometer and rings. For example, a Mach-Zehnder filter can be used to eliminate unwanted transmission passbands of a periodic ring filter. Here, the ring filter can provide fine wavelength filtering, and the Mach-Zehnder filter can provide a coarse blocking function.

[0052] As mentioned above, Figure 4Provided as an example. Other examples may differ from the Figure 4 described.

[0053] Figure 5 is a flow chart of an example process 500 associated with optical channel monitoring. In some embodiments, Figure 5 One or more process blocks of are performed by an optical device (eg, optical device 100).

[0054] like Figure 5 As shown, process 500 may include directing, by a switching engine of an optical device, one or more wavelength-channel subsets of an optical signal to a tunable filter of the optical device (block 510). In some embodiments, directing the one or more wavelength-channel subsets of the optical signal includes sequentially directing a first wavelength-channel subset of the optical signal to the tunable filter while blocking a second wavelength-channel subset of the optical signal, and directing a second wavelength-channel subset of the optical signal to the tunable filter while blocking the first wavelength-channel subset of the optical signal. In some embodiments, the one or more wavelength-channel subsets include two or more interleaved optical spectra.

[0055] like Figure 5 As further shown in FIG5 , process 500 may include scanning, by a tunable filter, respective wavelength channels of one or more subsets of wavelength channels of the optical signal (block 520). In some embodiments, scanning through the respective wavelength channels includes sequentially: scanning through the respective wavelength channels of a first subset of wavelength channels of the optical signal, and scanning through the respective wavelength channels of a second subset of wavelength channels of the optical signal. In some embodiments, process 500 includes measuring the respective wavelength channels output by the tunable filter.

[0056] although Figure 5 Example blocks of process 500 are shown, but in some implementations, process 500 includes Figure 5 5. In some embodiments, the process 500 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. Additionally or alternatively, two or more blocks of process 500 may be executed in parallel.

[0057] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementation to the precise form disclosed. Modifications and variations may be made based on the above disclosure or may be obtained from the practice of implementation. In addition, any embodiment described herein may be combined, unless the foregoing disclosure clearly provides reasons why one or more embodiments may not be combined.

[0058] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. It will be apparent that the systems and / or methods described herein can be implemented in different forms of hardware, firmware, or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit these embodiments. Therefore, the operation and behavior of the systems and / or methods are described herein without reference to specific software code—it should be understood that software and hardware can be designed to implement the systems and / or methods based on the description herein. The use of the term "sequentially" and its derivatives is merely intended to indicate that a second condition or operation follows a first condition or operation at a later time period. This is not intended to exclude other intervening or recurring situations or operations.

[0059] Even though particular combinations of features are listed in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various embodiments. In fact, many of these features can be combined in ways not specifically stated in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of the various embodiments includes the combination of each dependent claim with every other claim in the claim set. As used herein, a phrase referring to "at least one of..." in a series of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiple identical items.

[0060] When a component or one or more components is described or stated (in a single claim or across multiple claims) as performing multiple operations or being configured to perform multiple operations, the language is intended to broadly encompass a variety of architectures and environments. For example, unless otherwise expressly stated (e.g., via the use of "first component" and "second component" or other language that distinguishes components in a claim), the language is intended to encompass a single component that performs or is configured to perform all operations, a group of components that collectively perform or are configured to perform all operations, a first component that performs or is configured to perform a first operation and a second component that performs or is configured to perform a second operation, or any combination of components that perform or are configured to perform operations. For example, when a claim has "one or more components configured to: perform X; perform Y; and perform Z," the claim should be interpreted to mean "configured to perform X; one or more (possibly different) components configured to perform Y; and one or more (possibly different) components configured to perform Z."

[0061] Unless explicitly stated, any element, action or instruction used herein should not be considered as key or necessary. In addition, as used herein, the articles "one" and "an" are intended to include one or more projects and can be used interchangeably with "one or more". In addition, as used herein, the article "the" is intended to include one or more projects related to the article "the", and can be used interchangeably with "the one or more". In addition, as used herein, the term "set" is intended to include one or more projects (for example, related projects, unrelated projects, or a combination of related and unrelated projects), and can be used interchangeably with "one or more". In the case of only being intended to a project, phrase "only one" or similar language is used. In addition, as used herein, the terms "have (has)", "have (have)", "having (having)" etc. are intended to be open terms. In addition, the phrase "based on" is intended to mean "based at least in part on", unless explicitly stated otherwise. Furthermore, as used herein, the term "or" when used in a series is inclusive and can be used interchangeably with "and / or" unless expressly stated otherwise (e.g., if used in conjunction with "any of" or "only one of").

Claims

1. An optical device combining a wavelength selective switch and an optical channel monitor, comprising: A first port group, the first port group is used for wavelength division switching, and includes a first input port for transmitting a first optical signal; a second port group, the second port group being used for optical channel monitoring and comprising a second input port for transmitting a second optical signal; a dispersive element, the dispersive element being positioned in an optical path of the first optical signal and the second optical signal, the dispersive element being configured to separate the first optical signal and the second optical signal into dispersed wavelength channels; a switching engine, the switching engine being positioned in an optical path of the dispersive wavelength channel, the switching engine being configured to: directing one or more wavelength channels of the first optical signal to corresponding output ports of the first port group, and directing one or more wavelength-channel subsets of the second optical signal to output ports of the second port group; as well as A tunable filter is provided to scan through corresponding wavelength channels of the one or more subsets of wavelength channels of the second optical signal.

2. The optical device of claim 1 , wherein to direct the one or more wavelength-channel subsets of the second optical signal, the switching engine is to sequentially: directing a first subset of wavelength channels of the second optical signal to the output ports of the second port group while blocking a second subset of wavelength channels of the second optical signal; and directing the second subset of wavelength channels of the second optical signal to the output ports of the second port group while blocking the first subset of wavelength channels of the second optical signal, The first subset of wavelength channels is different from the second subset of wavelength channels.

3. The optical device of claim 2, wherein the first subset of wavelength channels has no common wavelength channels with the second subset of wavelength channels.

4. The optical device of claim 1, wherein the one or more subsets of wavelength channels comprise two or more interleaved optical spectra. 5 . The optical device according to claim 1 , wherein the second input port is one second input port among a plurality of second input ports of the second port group.

6. The optical device of claim 1, wherein the switching engine comprises a digital light processor switching engine, a liquid crystal on silicon switching engine, or a micro-electromechanical mirror system switching engine.

7. The optical device according to claim 1, further comprising: A monitoring element is used to measure the corresponding wavelength channel output by the tunable filter, and the monitoring element includes one or more photodetectors and a signal processing unit.

8. The optical device according to claim 7, wherein the tunable filter and the monitoring element are integrated in a silicon photonic chip.

9. An optical channel monitor, comprising: a dispersive element positioned in a light path of an optical signal, the dispersive element being configured to separate the optical signal into dispersed wavelength channels; a switching engine positioned in an optical path of the dispersive wavelength channels, the switching engine configured to direct one or more subsets of the wavelength channels of the optical signal; as well as A tunable filter is provided for scanning corresponding wavelength channels of the one or more subsets of wavelength channels through the optical signal.

10. The optical channel monitor of claim 9, further comprising: a polarization beam splitter, configured to separate the optical signal into a first signal having a first polarization and a second signal having a second polarization; as well as a polarization rotator, the polarization rotator being configured to rotate the polarization of the first signal or the second signal, wherein the tunable filter comprises a first tunable filter component and a second tunable filter component, and wherein the switching engine is configured to direct the wavelength-channel subset of the first signal to a first surface coupler of the tunable filter for the first tunable filter component, and to direct the wavelength-channel subset of the second signal to a second surface coupler of the tunable filter for the second tunable filter component.

11. The optical channel monitor of claim 9, wherein to direct the one or more wavelength-channel subsets of the optical signal, the switching engine is to sequentially: directing a first subset of wavelength channels of the optical signal while blocking a second subset of wavelength channels of the optical signal; and directing the second subset of wavelength channels of the optical signal while blocking the first subset of wavelength channels of the optical signal, The first subset of wavelength channels is different from the second subset of wavelength channels.

12. The optical channel monitor of claim 9, wherein the tunable filter is integrated into a silicon photonic chip.

13. The optical channel monitor of claim 9, further comprising: A monitoring element is used to measure the corresponding wavelength channel output by the tunable filter, and the monitoring element includes one or more photodetectors and a signal processing unit.

14. The optical channel monitor of claim 9, wherein the switch engine comprises a digital light processor switch engine, a liquid crystal on silicon switch engine, or a micro-electromechanical mirror system switch engine.

15. The optical channel monitor of claim 9, wherein the one or more subsets of wavelength channels comprise two or more interleaved optical spectrums.

16. A method comprising: directing, by a switching engine of an optical device, one or more subsets of wavelength channels of an optical signal to a tunable filter of the optical device; as well as A corresponding wavelength channel of the one or more subsets of wavelength channels of the optical signal is scanned by the tunable filter.

17. The method of claim 16, wherein directing the one or more wavelength-channel subsets of the optical signal comprises sequentially: directing a first subset of wavelength channels of the optical signal to the tunable filter while blocking a second subset of wavelength channels of the optical signal; and The second subset of wavelength channels of the optical signal is directed to the tunable filter while blocking the first subset of wavelength channels of the optical signal.

18. The method of claim 17, wherein scanning through the respective wavelength channels comprises sequentially: scanning the corresponding wavelength-channels of the first subset of wavelength-channels through the optical signal; and The corresponding wavelength-channels of the second subset of wavelength-channels are scanned through the optical signal.

19. The method according to claim 16, further comprising: The corresponding wavelength channel output by the tunable filter is measured.

20. The method of claim 16, wherein the one or more subsets of wavelength channels comprise two or more interleaved optical spectra.

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