Optical measurement system with multiple emission sites

Abstract

The present disclosure relates to optical measurement systems having multiple launch sites. Various embodiments disclosed herein describe optical measurement systems for characterizing a sample. The optical measurement systems are capable of selectively launching light from different numbers of launch groups, and can include a multi-stage optical switch network that can be controlled to route light to a desired number of launch groups. The optical measurement systems are also capable of measuring light using a corresponding number of detector groups. The optical measurement systems are capable of performing measurements using multiple different wavelengths, where different groups of these wavelengths can be measured using different numbers of launch groups (and corresponding detector groups).

Description

Technical Field

[0001] The embodiments described herein relate to optical measurement systems. More specifically, the embodiments describe optical measurement systems that can selectively output light to different sets of emission sites. Background Technology

[0002] Optical measurement systems can be used to identify the presence, type, and / or one or more properties of objects or substances in the environment surrounding the system. In some cases, optical measurement systems perform spectral measurements by emitting light at multiple wavelengths and measuring the light returning to the system. The relative amount of light returning at each wavelength provides information about the properties of one or more materials being measured. As the number of wavelengths measured by an optical measurement system and the number of unique measurement locations each increase, these optical systems may require increasingly complex architectures, which may further increase the power consumption and / or measurement time required to perform the measurements. Therefore, a compact, time-saving, and power-efficient optical measurement system may be required. Summary of the Invention

[0003] This document describes optical measurement systems and methods for determining one or more properties of a sample. In some embodiments of these embodiments, the optical measurement system includes a light source unit capable of generating light of any wavelength among a plurality of wavelengths, a multi-stage optical switch network optically connected to the light source unit and including a plurality of outputs, and a plurality of emission groups, each emission group being optically connected to a corresponding output of the plurality of outputs. The optical measurement system also includes a plurality of detector groups, and a controller configured to perform a measurement sequence using the light source unit, the multi-stage optical switch network, the plurality of emission groups, and the plurality of detector groups. The measurement sequence includes: dividing the plurality of wavelengths into a plurality of groups, wherein each of the plurality of groups is associated with a different corresponding output configuration; and performing a set of measurements at the corresponding output configuration for each of the plurality of wavelengths.

[0004] In some cases, the plurality of groups includes a first group associated with a first output configuration and a second group associated with a second output configuration. Performing the group measurement for each of the plurality of wavelengths includes performing the first group measurement for a first wavelength of the first group. Each measurement in the first group includes: generating light of a first wavelength using a light source unit; emitting the generated light from an emission group correspondence set selected from the plurality of emission groups and having a first number of emission groups corresponding to the first output configuration; and measuring the returned light received during the emission of the generated light using a detector group correspondence set selected from the plurality of detector groups and having a first number of detector groups.

[0005] The measurements in this set of measurements also include performing a second set of measurements on a second wavelength of the second set. Each measurement in the second set of measurements includes: generating light of the second wavelength using a light source unit; emitting the generated light from a set of emission group correspondences selected from the plurality of emission groups and having a second number of emission groups corresponding to the second output configuration; and measuring the returned light received during the emission of the generated light using a set of detector group correspondences selected from the plurality of detector groups and having a second number of detector groups.

[0006] In some cases, the first set of measurements includes multiple measurements with different emission group correspondence sets and different detector group correspondence sets. Additionally or alternatively, each measurement in the first set includes configuring a multi-stage optical switching network to route light of a first wavelength to the emission group correspondence set. In some cases, each of these measurements also includes measuring background light received before the emitted light is emitted using the detector group correspondence set, such that configuring the multi-stage optical switching network in each measurement of the first set is performed at least partially simultaneously with measuring the background light.

[0007] In other embodiments of these implementations, the optical measurement system includes a light source unit capable of generating light of any wavelength from a plurality of wavelengths, a multi-stage optical switch network optically connected to the light source unit, and a plurality of emission groups. The multi-stage optical switch network includes a plurality of outputs, each optically connected to a corresponding emission group among the plurality of emission groups. Furthermore, the multi-stage optical switch network can be controlled to selectively route light generated by the light source unit to the plurality of emission groups with different output configurations. In some cases, the multi-stage optical switch network includes a plurality of inputs.

[0008] In some variations, the optical measurement system further includes a photonic integrated circuit, which includes a light source unit, a multi-level optical network, and multiple emission groups. In some of these variations, each emission group includes a corresponding output coupler configured to emit light from the photonic integrated circuit. Additionally or alternatively, the optical measurement system also includes multiple detector groups and an interposer layer, wherein the photonic integrated circuit and the multiple detector groups are mounted on the interposer layer.

[0009] Additionally or alternatively, the optical measurement system may include a first wavelength locking unit. In some of these variations, the multi-stage optical switching network includes a first stage and a second stage, the first stage including a first controllable switch. The first controllable switch includes a first tap, and the first wavelength locking unit is optically connected to the multi-stage optical switching network via the first tap. In some of these variations, the first stage further includes a second controllable switch having a second tap, and the second wavelength locking unit is optically connected to the multi-stage optical switching network via the second tap.

[0010] In other embodiments, the method for characterizing a sample includes selecting a plurality of wavelengths and performing a sequence of measurements to generate a plurality of sets of output signals. The measurement sequence includes dividing the plurality of wavelengths into a plurality of groups, wherein each of the plurality of groups is associated with a different corresponding output configuration. The measurement sequence also includes performing a set of measurements on the sample for each of the plurality of wavelengths under the corresponding output configuration, and generating a corresponding set of output signals for each set of measurements. The method further includes using the plurality of sets of output signals to determine one or more properties of the sample.

[0011] In some of these methods, the plurality of groups includes a first group associated with a first output configuration and a second group associated with a second output configuration. Performing this group of measurements on the sample for each of the plurality of wavelengths includes performing a first group of measurements on the sample for a first wavelength of the first group. Each measurement in the first group of measurements includes generating light of a first wavelength and emitting the generated light from an emission group correspondence set selected from a plurality of emission groups and having a first number of emission groups corresponding to the first output configuration. Each measurement also includes measuring the returned light received during the emission of the generated light using a detector group correspondence set selected from a plurality of detector groups and having a first number of detector groups.

[0012] Performing this set of measurements on the sample for each of the plurality of wavelengths also includes performing a second set of measurements on the sample for a second wavelength of the second set. Each measurement in the second set includes generating light of the second wavelength and emitting the generated light from a set of emission group correspondences selected from a plurality of emission groups and having a second number of emission groups corresponding to the second output configuration. Each measurement also includes measuring the returned light received during the emission of the generated light using a set of detector group correspondences selected from the plurality of detector groups and having a second number of detector groups.

[0013] In some of these methods, the first set of measurements includes multiple measurements with different sets of emission group correspondences and different sets of detector group correspondences. Additionally or alternatively, each measurement in the first set of measurements further includes configuring a multi-stage optical switching network to route light generated at a first wavelength to the emission group correspondences. In some of these methods, each measurement in the first set of measurements further includes measuring background light received before the emitted light using the detector group correspondences. In these cases, configuring the multi-stage optical switching network in each measurement of the first set of measurements is performed at least partially simultaneously with the measurement of the background light.

[0014] In other variations of these methods, the measurement sequence is divided into multiple subsequences. In some examples, each subsequence has a corresponding set of wavelengths from the multiple wavelength groups and a set of emission group correspondences selected from multiple emission groups. Each subsequence includes sample measurements for each wavelength in the corresponding set of wavelengths, during which light of that wavelength is emitted from the set of emission group correspondences.

[0015] In addition to the exemplary aspects and embodiments described herein, further aspects and embodiments will become apparent from the accompanying drawings and by studying the following description. Attached Figure Description

[0016] This disclosure will be readily understood from the following detailed description taken in conjunction with the accompanying drawings, wherein similar reference numerals denote similar structural elements, and wherein:

[0017] Figure 1A A cross-sectional side view of the device incorporated into the optical measurement system as described herein is shown. Figure 1B It shows Figure 1A A top view of the device.

[0018] Figure 2 A schematic diagram of a variation of the optical measurement system as described herein is shown.

[0019] Figures 3A to 3D A schematic diagram depicts a variation of a controllable switch that can be used with the multi-stage optical switch network described herein.

[0020] Figure 4 A schematic diagram of a variant of an optical measurement system with a multi-stage optical switch network is shown, which has one input and four outputs.

[0021] Figure 5 A schematic diagram of a variant of an optical measurement system with a multi-stage optical switch network is shown, which has two inputs and four outputs.

[0022] Figure 6 A schematic diagram of a variant of an optical measurement system with a multi-stage optical switch network is shown, which has four inputs and four outputs.

[0023] Figure 7 A method for performing measurement sequences is described.

[0024] Figure 8 A block diagram depicts a measurement sequence comprising multiple subsequences corresponding to different emission groups.

[0025] Figure 9 A time series diagram depicting a measurement sequence comprising multiple individual measurements is presented.

[0026] It should be understood that the proportions and dimensions (relative or absolute) of various features and elements (and sets and subsets thereof), as well as the boundaries, spacing and positional relationships therebetween, are provided in the accompanying drawings solely to facilitate understanding of the various embodiments described herein, and are therefore unnecessarily presented or shown for scaling and are not intended to indicate any preference or requirement for the illustrated embodiments to exclude embodiments in combination with them.

[0027] Directional terms such as “top,” “bottom,” “upper,” “lower,” “front,” “rear,” “above,” “below,” “above,” “below,” “left,” “right,” “vertical,” and “horizontal,” etc., are used with reference to the orientation of some components in some of the figures described below and are not intended to be limiting. Because components in various embodiments may be positioned in multiple different orientations, directional terms are used for illustrative purposes only and are not intended to be limiting in any way. Directional terms are intended to be interpreted broadly and should therefore not be construed as excluding components oriented in different ways. Furthermore, as used herein, the phrase “at least one of” following a series of items separated by the terms “and” or “or” modifies the list as a whole, not each member of the list. The phrase “at least one of” does not require selection of at least one of each of the listed items; rather, the phrase allows for the inclusion of at least one of any item in the list and / or at least one of any combination of items and / or at least one of each item in the list. For example, the phrases "at least one of A, B, and C" or "at least one of A, B, or C" each refer to only A, only B, or only C; any combination of A, B, and C; and / or one or more of each of A, B, and C. Similarly, it should be understood that the order of elements presented with respect to the combined or separate lists provided herein should not be construed as limiting this disclosure to the order provided. Detailed Implementation

[0028] Cross-references to related applications

[0029] This application is a non-provisional application of U.S. Provisional Patent Application No. 63 / 323,721, filed March 25, 2022, and claims the benefit of that U.S. Provisional Patent Application under 35 U.S.SC §119(e), the contents of which are incorporated herein by reference as if fully disclosed herein.

[0030] Reference will now be made specifically to the representative embodiments shown in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to a single preferred embodiment. Rather, it is intended to cover alternative forms, modifications, and equivalents that may be included within the substance and scope of the embodiments defined by the appended claims.

[0031] The following disclosure relates to embodiments of an optical measurement system having multiple emission points, and methods for performing measurements using these optical measurement systems. The optical measurement system is capable of simultaneously routing light to an adjustable number of emission groups (each emission group associated with one or more emission points), thereby allowing the optical system to perform multiple measurements, each using a different number of emission groups. In other words, a first set of measurements involves simultaneously emitting light from a first number of emission groups, and a second set of measurements involves simultaneously emitting light from a second number (different from the first number) of emission groups.

[0032] Optical measurement systems can perform measurement sequences using multiple wavelengths, where a set of individual measurements (e.g., at least one measurement) is performed for each of these wavelengths. In these cases, the multiple wavelengths are divided into multiple groups, each group associated with a different number of emission groups (i.e., the light generated by the optical measurement system is split between emission groups). Therefore, for a given wavelength, this set of individual measurements will be performed using a certain number of simultaneous emission groups set based on the group to which the wavelength is assigned.

[0033] When performing spectral measurements using multiple different wavelengths, signal quality can exhibit wavelength-dependent variations. Depending on what the optical measurement system is measuring (e.g., the type or characteristics of the sample being measured in the environment surrounding the optical measurement system), the signal-to-noise ratio (“SNR”) measured individually at different wavelengths may be limited by different noise sources. For example, sample measurements performed at some wavelengths will be limited by fundamental noise. In these cases, the SNR can be increased by increasing the amount of light introduced into the sample for these wavelengths. On the other hand, measurements performed at other wavelengths may be limited by coherent noise. In these cases, increasing the amount of light introduced into the sample at these wavelengths will not improve the SNR. The optical measurement systems described herein can take into account the different noise sources expected when measuring the sample and can accordingly select different measurement types for different wavelengths (as will be discussed in more detail below).

[0034] The optical measurement system described herein typically includes a light source unit, a multi-stage optical switch network, multiple emission groups, and multiple detector groups. The light source unit has one or more outputs and is capable of generating light of any wavelength from a plurality of different wavelengths (including corresponding groups of wavelengths for each output of the light source unit). In other words, the light source unit can be controlled to generate light selected from these plurality of different wavelengths at any given time point (i.e., it is not necessary to generate multiple different wavelengths simultaneously).

[0035] The light source unit is optically connected (i.e., capable of transmitting light to) a multi-stage optical switch network, thereby allowing the multi-stage optical switch network to receive light from the light source unit (e.g., via one or more outputs of the light source unit). The multi-stage optical switch network includes multiple outputs, each optically connected to a corresponding emission group among the multiple emission groups (however, it should be understood that the multi-stage optical switch network may include one or more additional outputs not optically connected to a corresponding emission group). The multi-stage optical switch network can be controlled to selectively route light to some or all of its outputs (and thus to some or all of the multiple emission groups), which facilitates different measurement types as described herein. Each emission group is associated with a corresponding group of emission sites, where each emission site corresponds to a spatial location where light is emitted outward from the optical measurement system (e.g., toward the sample). Overall, the optical measurement system is capable of selectively emitting light to different locations on the sample, and the number of different emission locations receiving light simultaneously can be further selected.

[0036] The multiple detector array measures light received by the optical measurement system (e.g., light emitted from the optical measurement system toward the sample and returning to the optical measurement system). The light measured by the multiple detector array can be analyzed to determine one or more properties of the environment surrounding the optical measurement system (e.g., the presence, type, and / or one or more characteristics of an object measured by the optical measurement system), collectively referred to herein as the “sample.” Light can be measured by the detector array simultaneously with the emission array (to determine how the emitted light interacts with the sample), and optionally, light can be measured while the emission array is not actively emitting light (to measure background light that may aid in background correction operations).

[0037] For each measurement in a given measurement sequence, the optical measurement system controls (e.g., via a controller) a light source unit to generate light of the corresponding wavelength. The optical measurement system also controls a multi-stage optical switching network to route the light of that wavelength to a predetermined number of emission groups. The generated light is emitted from these emission groups (and thus can leave the optical measurement system), with a portion returning to the optical measurement system (e.g., through interaction with a sample outside the optical measurement system). When the optical measurement system emits the generated light, a detector group receives the returned light corresponding to the set of measurements.

[0038] The implementation scheme of the optical measurement system described herein can be incorporated into a device with a housing. In some cases, the wearable device can operate independently to perform measurements using the optical measurement system, or it can be a multifunctional device capable of performing additional functions (not discussed in detail herein). For example, in some cases, the optical measurement system can be incorporated into a smartphone, tablet computer, laptop or desktop computer, smartwatch, or other electronic device (collectively referred to herein as "electronic device" for ease of discussion).

[0039] The device may include a display (which may be a touchscreen display) that provides graphic output that can be viewed through or on the outer surface of the device. When the display is configured as a touchscreen, it may be able to receive touch input at the outer surface. The device may include a cover (e.g., a cover glass) located above the display, forming at least a portion of the outer surface. The display is capable of providing graphic output and, when configured as a touchscreen, is capable of receiving touch input through the cover. In some embodiments, the display includes one or more sensors (e.g., capacitive touch sensors, ultrasonic sensors, or other touch sensors) positioned above, below, or integrated with the display portion. In various embodiments, the graphic output of the display responds to input provided to the electronic device. Portable electronic devices may include typical additional components of computing devices, including processing units, memory, input devices, output devices, additional sensors, etc.

[0040] refer to Figures 1A to 9 These and other implementation schemes will be discussed here. However, those skilled in the art will readily understand that the detailed descriptions given herein with respect to the accompanying drawings are for illustrative purposes only and should not be construed as limiting.

[0041] Figure 1A and Figure 1B An example of a device 100 housing an optical measurement system 102 as described herein is shown. As shown, device 100 includes a housing 104 having a top outer surface 106. This outer surface 106 defines a sampling interface 107 for the optical measurement system 102, through which light emitted by the optical measurement system 102 can exit device 100 and re-enter device 100 to return to the optical measurement system 102. The sampling interface 107 includes at least one window defining one or more emission regions 108 through which light emitted by the optical measurement system 102 can exit device 100 and one or more collection regions 110 through which light entering device 100 can reach predetermined portions of the optical measurement system 102, such as detectors.

[0042] exist Figure 1A and Figure 1B In the variant shown, the device includes multiple emission areas 108 and multiple collection areas 110. Although Figure 1A and Figure 1BAn equal number of emission regions 108 and collection regions 110 are depicted; however, in other cases, the sampling interface 107 has an unequal number of emission regions 108 and collection regions 110. Each emission region 108 and collection region 110 is transparent at each wavelength (collectively, the “measurement wavelength”) used by the optical measurement system 102 to perform the measurements discussed herein. Each emission region 108 and collection region 110 may be defined by corresponding windows (transparent at the measurement wavelength) separated from each other by one or more opaque portions of the housing (i.e., absorbing or otherwise blocking light transmission at the measurement wavelength). In other variations, some or all of the emission regions 108 and / or collection regions 110 are defined within a common window (e.g., using a mask that is opaque at the measurement wavelength). Additionally or alternatively, the device 102 may include barriers, baffles, or other light-blocking structures (not shown) that may at least partially define some or all of the emission regions 108 and collection regions 110. These light-blocking structures block stray light and act as guides to limit the path that light can take between the optical measurement system 102 and the sampling interface 107.

[0043] like Figure 1A and Figure 1B As shown, the optical measurement system 102 includes a photonic integrated circuit 112. The photonic integrated circuit 112 includes at least a multi-level optical switching network (not shown) and multiple emission groups (not shown), and is capable of selectively emitting light from multiple spatial locations on the photonic integrated circuit 112 via the multiple emission groups. Light emitted from the photonic integrated circuit 112 exits the device 100 via a sampling interface 107 (e.g., via an emission region 108). In some variations, the optical measurement system 102 optionally includes one or more light modification components (schematically shown as block 114) positioned between the photonic integrated circuit 112 and the sampling interface 107, which alter the light-emitting photonic integrated circuit 112 before the light reaches the sampling interface 107. For example, the light modification component 114 may include one or more lenses (which alter the divergence and / or direction of light), one or more diffusers, mirrors, etc. Additionally or alternatively, the sampling interface itself may act as a light modification component (e.g., it may have integrated lenses, etc., capable of altering the divergence and / or direction of light passing through it). Each emission group interacts with the sampling interface 107 and any intermediate components (such as the light modification component 114) to control the position of light emitted from the device 100, and thus define the emission point of the optical measurement system 102.

[0044] The optical measurement system also includes multiple detector groups 116, each comprising a corresponding group of detectors. Each detector group 116 is positioned within the device 100 to receive light that has entered the device 100 through a sample interface (e.g., via a corresponding collection area 110). In some variations, the optical measurement system 102 includes one or more light-modifying components (schematically shown as box 118) positioned between a sampling interface 107 and at least one detector group 116, which modify the light entering the device 100 before it reaches the corresponding detector group (or groups). The light-modifying component 118 may include one or more lenses (which alter the divergence and / or direction of light), one or more diffusers, mirrors, etc. Additionally or alternatively, the sampling interface 107 may act as a light-modifying component.

[0045] In some cases, the photonic integrated circuit 112 and multiple detector groups 116 are mounted to a common component. For example, in Figure 1A and Figure 1B In the illustrated variant, the optical measurement system 102 includes an interposer 120. In these cases, the photonic integrated circuit 112 and the plurality of detectors 116 are all mounted on the interposer 120, which then serves as an electrical interface for these components (e.g., routing signals to and / or from these components). In some cases, the interposer also acts as a heat sink. In other variants, the photonic integrated circuit 112 is mounted to components that are separate from some or all of the plurality of detector groups 116. In still other variants, some or all of the plurality of detector groups 116 are directly mounted (or otherwise integrated into) a portion of the photonic integrated circuit 112.

[0046] Figure 1A and Figure 1B The device 100 shown can utilize any optical measurement system described herein (such as those described below relative to...). Figures 2 to 6 Those optical measurement systems described herein) and perform any measurement sequence described herein (such as those described below relative to...). Figures 7 to 9 Those measurement sequences mentioned above). For example, Figure 2 A schematic diagram of an optical measurement system 200 as described herein is shown. The optical measurement system 200 includes a light source unit 202, a multi-stage optical switch network 204, multiple emission groups 206, and multiple detector groups 208. The optical measurement system 200 is capable of generating light and selectively routing the light to some or all of the multiple emission groups 206. Light can exit the optical measurement system 200 via the multiple emission groups 206, and some or all of the detector groups 208 can be used to measure the light returning to the optical measurement system 200.

[0047] Specifically, the light source unit 202 includes a set of light sources (not shown), each of which can selectively operate to emit light of a corresponding set of wavelengths. Each light source can be any component capable of generating one or more specific wavelengths of light, such as a light-emitting diode or a laser. The laser can include semiconductor lasers, such as laser diodes (e.g., distributed Bragg reflector lasers, distributed feedback lasers, external cavity lasers), quantum cascade lasers, etc. A given light source can be single-frequency (fixed wavelength) or tunable to selectively generate one wavelength from a plurality of wavelengths (i.e., the light source can be controlled to output different wavelengths at different times). The set of light sources can include any suitable combination of light sources and can work together to generate light of any wavelength from a plurality of different wavelengths.

[0048] The light source unit 202 includes one or more output terminals 210, which are optically connected to a multi-stage optical switching network 204 to route light there. These one or more output terminals 210 collectively allow the light source unit 202 to route any wavelength from a plurality of different wavelengths to the multi-stage optical switching network 204. Although in Figure 2 A single output terminal 210 is shown, but it should be understood that in some variations, the light source unit 202 includes multiple output terminals. Each output terminal 210 can route a corresponding set of wavelengths to a multi-stage optical switching network 204, which together constitute multiple different wavelengths that can be routed to the multi-stage optical switching network 204. In some cases, the light source unit 202 includes more light sources than output terminals 210. In this case, the light source unit 202 includes one or more multiplexers (not shown) to allow multiple light sources to contribute light to a single output terminal 210. This allows the light source unit 202 to include several light sources (and thus be able to generate several different wavelengths) while having a relatively small number of output terminals 210.

[0049] It should be understood that the light source unit 202 may also include one or more additional outputs (i.e., those that do not route light to the multi-stage optical switching network 204), instead routing light to other parts of the optical measurement system 200. For example, one or more of these additional outputs may route light to wavelength-locking units (such as those discussed in more detail below). In some cases, the light source unit 202 is capable of generating more wavelengths than those routed to the multi-stage optical switching network 204 during operation of the optical measurement system 200 (i.e., the light source unit 202 is capable of generating any of the multiple wavelengths, but the optical measurement system 200 uses only a subset of these wavelengths as the measurement wavelengths for performing measurements using the multi-stage optical switching network 204). This can support additional functions of the optical measurement system 200 beyond those described in this application. The following is relative to... Figures 4 to 6 Examples of light source units applicable to the optical measurement system described herein are discussed in more detail.

[0050] The multi-stage optical switch network 204 has at least one input (in some cases, multiple inputs) and multiple outputs 210. The multi-stage optical switch network 204 receives light from the light source unit 202 via the one or more inputs, wherein each input is optically connected to a corresponding output 210 of the light source unit 202. The inputs of the multi-stage optical switch network 204 are located at... Figure 2 Unless otherwise specified, and it should be understood, the optical measurement system 200 may optionally include additional components (not shown) between the output 210 of the light source unit 202 and the corresponding input of the multi-stage optical switching network 204. These additional components may be useful, for example, in cases where it is desired to modify the light generated by the light source unit 202 before it reaches the multi-stage optical switching network 204. Each of the plurality of outputs 202 is optically connected to a corresponding emission group in the plurality of emission groups 206, thereby allowing the multi-stage optical switching network 204 to selectively route light to some or all of the plurality of emission groups 206.

[0051] Specifically, the multi-stage optical switching network 204 can be controlled to acquire light of a predetermined wavelength received at one of its inputs and simultaneously direct that light to one or more of its outputs 212. In some cases, the multi-stage optical switching network 204 is controlled to direct light to a single output 212. In other cases, the multi-stage optical switching network 204 is controlled to split the light among multiple outputs 212, such that the light is simultaneously directed to multiple outputs. For the purposes of this application, the “output configuration” (also referred to herein as “output resolution”) of an optical measurement system refers to the number of unique emission groups that simultaneously receive light. The optical measurement system is capable of emitting light in different output configurations, each output configuration corresponding to a different number of emission groups that simultaneously receive light.

[0052] A multi-stage optical switch network can be configured to set the output configuration of an optical measurement system by setting the number of output terminals that simultaneously output light received by the light source unit. The number of different output configurations of the optical measurement system depends on the number of output terminals of the multi-stage optical switch network. For example, in... Figure 2In the illustrated embodiment, the multi-stage optical switching network 204 has four outputs and can output light in four different output configurations (i.e., output to a single output 212 or split between two, three, or four of the outputs 212). In a given output configuration, particularly those using only a subset of the outputs of the multi-stage optical switching network 204, the optical measurement system can include multiple different sub-configurations where different subsets of the outputs simultaneously receive light. In other words, multiple unique emission groups 206 with the same output configuration may exist, and the optical measurement system can perform individual measurements at some or all of these unique emission groups during a measurement sequence. Each of these individual measurements is considered a measurement performed using the same output configuration because the same number of emission groups simultaneously receive light. When light is split between the multiple outputs of a given output configuration, the multi-stage optical switching network 204 can provide any light distribution (equal or unequal splits) among these outputs as needed. The details of how to control the multi-level optical switch network 204 to switch between different output configurations (and different groups of transmitters for a given output configuration) will be discussed in more detail below.

[0053] The multi-level optical switch network 204 and multiple emitter groups 206 are formed as part of the photonic integrated circuit 214. Some or all of the light source units 202 may also be integrated into the photonic integrated circuit 214. For example, in some cases, the light source of the light source unit 202 and any multiplexer are integrated into the photonic integrated circuit 214 (such as...). Figure 2 (As shown in the diagram). In other cases, some or all of the light sources generate light from outside the photonic integrated circuit 214, and the light from these sources is coupled into the photonic integrated circuit 214 to reach the multi-stage optical switching network 204. The photonic integrated circuit 214 may utilize waveguides to optically connect components on the photonic integrated circuit 214. For example, in Figure 2 In the embodiment shown, the output terminal 210 of the light source unit 202 and the input and output terminals 212 of the multi-level optical switch network 204 can be waveguides.

[0054] Each of the plurality of emitter groups 206 is optically connected to a corresponding output terminal 212 of the multi-stage optical switch network 204 and can emit light received from the light source unit 202 out of the photonic integrated circuit 214. For example, the photonic integrated circuit 214 may include a plurality of output couplers (e.g., edge couplers, vertical output couplers, etc.) for emitting light from the photonic integrated circuit 214, and each emitter group 206 may include at least one of these output couplers. Figure 2In the variant shown, each emission group 206 has an output coupler 216. Light emitted from the photonic integrated circuit 214 (e.g., via the output coupler 216) can exit the optical measurement system 200 (and any device incorporated into the optical measurement system 200) at one or more emission sites toward the sample (e.g., via the sampling interface discussed above with respect to FIG1).

[0055] Each emission group 206 is associated with at least one emission site, such that light delivered to the emission group 206 can exit the optical measurement system 200 (and any device incorporated into the optical measurement system 200) at the corresponding emission site. Each emission site provides a unique entry position and / or angle to the sample. In some cases, this means that each emission site is spatially separated from (and not adjacent to) other emission sites (e.g., in situations such as those described above relative to...). Figure 1A and Figure 1B (At the sampling interface). In other variations, two or more emission positions may at least partially overlap, but are positioned at different angles away from the optical measurement system 200, such that light is directed to different parts of the sample.

[0056] The emission group 206 can be associated with a single emission site or multiple emission sites. For example, in Figure 2 In the illustrated variants, each emitter group 206 includes two output couplers 216. In some of these variants, each output coupler 216 within a given emitter group 206 is associated with a separate emitter site, such that a first output coupler of the emitter group emits light from the photonic integrated circuit 214 to a first emitter site, and a second output coupler 216 within the emitter group emits light from the photonic integrated circuit 214 to a second emitter site. In other variants, multiple output couplers within the emitter group emit light from the photonic integrated circuit 214 to a single emitter site. Additionally or alternatively, light emitted from the photonic integrated circuit 214 by a given output coupler 216 may be routed to two or more emitter sites, in which case the optical measurement system 200 is configured to split the light emitted by the output coupler 216 into multiple separate beams (each beam being routed to its own emitter site).

[0057] Therefore, multiple emission groups 206 can be used to emit light from the optical measurement system 200 at any of a plurality of emission sites (the selection and number of emission sites emitting light at a given time are determined at least in part by the operation of the multi-stage optical switch network 204). This light can be used to illuminate one or more portions of the sample, and a portion of the light can be returned to the system due to interaction with the sample (e.g., via reflection, scattering, etc.). The returned light can then be measured by some or all of the plurality of detector groups 208.

[0058] Each of the multiple detector groups 208 can be associated with a corresponding emission group 206. In these cases, the optical measurement system 200 can be configured such that a given detector group 208 will receive light emitted by its corresponding emission group 206 (and reflected from the environment surrounding the optical measurement system 200), but will not receive light already emitted by other emission groups 206. It should be understood that the light received by the optical measurement system 200 depends on the actual sample being measured, and therefore the optical measurement system 200 can be designed assuming it will be used to measure a target sample having one or more predetermined characteristics. For example, the optical measurement system 200 can be configured such that light entering the optical measurement system 200 at positions and angles within a predetermined range will reach the detector group 208. These positions and angles can be selected such that when measuring a sample having certain characteristics matching the target sample, the detector group 208 effectively receives only light from the corresponding emission group 206 (and little or no light from emission groups associated with other detector groups).

[0059] Each detector group 208 includes one or more groups of detector elements, wherein each group of detector elements is schematically represented by a single block 218. Each group includes at least one detector element, and each detector element is capable of generating a corresponding signal representing the light incident thereon. Individual detector elements may be independent detectors or sensing elements of a detector array (e.g., photodiodes of a photodiode array). It should be understood that different sensing elements of a single detector array may be associated with different detector groups 208. For example, a detector array may include a first subset of sensing elements associated with a first detector group and a second subset of sensing elements associated with a second detector group.

[0060] It should also be understood that the detector elements within a given detector group 208 do not need to be adjacent to each other. For example, in Figure 2 In a variant of the illustrated optical measurement system 200, each detector group 208 includes two sets of detector elements 218. In some of these variants, the optical measurement system 200 is configured such that each set of detector elements 218 measures light from different emission sites of a corresponding emission group 206. For example, light emitted from a first output coupler in a first emission group is measured by a first set of detector elements in the first detector group, and light emitted from a second output coupler in the first emission group is measured by a second set of detector elements in the first detector group. This allows for physical spacing between emission sites of a given emission group without requiring light emitted from these emission sites to be measured by the same detector elements. Overall, multiple detector groups 208 measure light emitted from the optical measurement system 200 via multiple emission groups 206, which facilitates the various measurements described herein.

[0061] Figure 2The document also illustrates a controller 220 that controls the operation of the optical measurement system 200 to perform various measurements as described herein. Specifically, the controller 220 can control the light source unit 202 to generate light of a selected wavelength at a selected output of the light source unit 202. The controller 220 can further control a multi-stage optical switching network 204 to configure the multi-stage optical switching network 204 to route light received from a selected output of the light source unit 202 to a selected number of outputs of the multi-stage optical switching network 204 (which in turn routes the light to a selected group of emission groups 206). The controller 220 can also control a plurality of detector groups 208 to generate output signals from some or all of the detector groups 208, which represent the light received by the detector groups 208. These output signals can be processed and analyzed to determine one or more properties of the sample. The controller 220 may include any combination of software, hardware, and firmware required to perform these functions (including any method steps described below), including, for example, one or more processors and / or application-specific integrated circuits (ASICs).

[0062] In some variations, the optical measurement system 200 includes a wavelength locking unit 222. The wavelength locking unit 222 can output a signal indicating the wavelength or wavelength variation of the light received by the wavelength locking unit 222. This signal can be used by the controller 220 to control the light source unit 202 (e.g., a light source within the light source unit that is generating light) to stabilize or otherwise adjust the wavelength of the light emitted by the light source unit 202. Even for a fixed-wavelength laser, the precise emission wavelength may vary slightly with changes in temperature and / or injection current, and therefore the wavelength locking unit 222 can provide feedback to the controller 200 to set a stable wavelength output before or during the measurement.

[0063] In some cases, wavelength locking unit 222 is optically connected to light source unit 202, allowing wavelength locking unit 222 to receive light directly from light source unit 202. However, when light source unit 202 has multiple outputs, wavelength locking unit 222 will need to de-spin light from each output of light source unit 202 to stabilize each wavelength generated by light source unit 202. In other cases, wavelength locking unit 222 receives light downstream of multi-stage optical switching network 204 (i.e., wavelength locking unit 222 de-spins the light after it has passed through multi-stage optical switching network 204). In these cases, wavelength locking unit 222 will need to de-spin light from each output 212 of multi-stage optical switching network 204, or will need to route light to the de-spinned output 212 (or multiple outputs) to perform wavelength stabilization / locking for all wavelengths output by light source unit 202.

[0064] In other cases, such as Figure 2As shown, wavelength locking unit 222 can receive light from a portion of the multi-stage optical switching network 204 (i.e., wavelength locking unit 222 receives light from one or more stages of the multi-stage optical switching network 204). These configurations can reduce the number of taps and / or routing requirements required to stabilize each wavelength generated by the light source unit 202. The following will be relative to... Figure 5 and Figure 6 Let's discuss examples of this.

[0065] As described above, the optical measurement system described herein includes a multi-stage optical switch network that can selectively output light with different output configurations. For this purpose, the multi-stage optical switch network includes multiple controllable switches divided into multiple distinct stages (each stage includes a corresponding group of controllable switches). Each controllable switch has at least one input and two outputs, wherein each input of the controllable switch receives light from an input of the multi-stage optical switch network or a previous stage, and each output of the controllable switch directs light to an output of a subsequent stage or the multi-stage optical switch network. Each controllable switch can be controlled such that light of a predetermined wavelength introduced to a predetermined input of the controllable switch is controllably directed to a first output of the switch, a second output of the switch, or split between the first and second outputs. In general, the multiple controllable switches can be controlled to configure the multi-stage optical switch network to create the necessary path for light of a given wavelength to travel from a predetermined input of the multi-stage optical switch network to a desired group of outputs of the multi-stage optical switch network.

[0066] In some variations, the controllable switch includes a first coupler, a second coupler, and a controllable phase tuner between the first and second couplers. The controllable phase tuner allows the controllable switch to selectively split light between a first output and a second output of the controllable switch. Figures 3A to 3D A variation of the controllable switch suitable for use with the multi-level optical switch network described herein is depicted. Figure 3A A variation of a 1×2 controllable switch 300 with a single input 302 and two outputs (a first output 304 and a second output 306) is shown. As shown, the controllable switch has a 1×2 coupler 308, a 2×2 coupler 310, and a controllable phase tuner 312 located between the 1×2 coupler 308 and the 2×2 coupler 310. In some variations, the 1×2 controllable switch 300 may include a 2×2 coupler instead of a 1×2 coupler 308, but one input of the 2×2 coupler remains open, such that the other input of the 2×2 coupler acts as a single input of the 1×2 controllable switch.

[0067] exist Figure 3AIn the variation of the 1×2 controllable switch shown, the 1×2 coupler 308 uses input 302 as its single input terminal and uses first pin 314 and second pin 316 as output terminals. Light received at input 302 of the 1×2 controllable switch 300 is split by the 1×2 coupler 308 between first pin 314 and second pin 316 according to a predetermined splitting ratio. Similarly, the 2×2 coupler 310 receives light from first pin 314 and second pin 316 as input and uses first output 304 and second output 306 of the 1×2 controllable switch 300 as output terminals. Light received at each input terminal of the 2×2 coupler 310 is split between first output 304 and second output 306 according to a corresponding predetermined splitting ratio. It should be understood that input 302, first output 304, second output 306, first pin 314, and second pin 316 can all be waveguides.

[0068] The relative amount of light coupled to the first output terminal 304 and the second output terminal 306 depends at least on: 1) the relative amount of light in the first pin 314 and the second pin 316 when light enters the 2×2 coupler 310; 2) the phase difference between the light in the first pin 314 and the second pin 316 when light enters the 2×2 coupler 310; and 3) the wavelength of the light. Thus, changing the phase difference between the first pin 314 and the second pin 316 alters the distribution of light between the first output terminal 304 and the second output terminal 306. Therefore, the controllable phase tuner 312 can be controlled to selectively adjust the phase difference between the first pin 314 and the second pin 316, thereby allowing the 1×2 controllable switch to controllably split light between its first output terminal 304 and its second output terminal 306. For example, the 1×2 controllable switch can use a controllable phase tuner 312 to selectively route all light to the first output 304, all light to the second output 306, or simultaneously route light to both the first output 304 and the second output 306 (i.e., splitting the light between the two outputs according to a target split ratio). Furthermore, the controllable phase tuner 312 can be adjusted to take into account the wavelength of the light introduced into the 1×2 controllable switch, allowing the desired output of the 1×2 controllable switch to be achieved for either of the measured wavelengths.

[0069] To adjust the phase difference between the first pin 314 and the second pin 316, the controllable phase tuner 312 includes one or more phase shifters that selectively modulate the phase of light passing through the first pin 314 or the second pin 316. Examples of suitable phase shifters include, for example, electro-optic phase shifters that use an applied electric field (e.g., via carrier injection) to change the refractive index of a portion of the waveguide, thermo-optic phase shifters that change the refractive index of a portion of the waveguide by changing the temperature of the waveguide, and optomechanical phase shifters (e.g., suspending the waveguide) in which a movable structure (e.g., suspending the waveguide) is moved to change the amount of evanescent coupling with the waveguide.

[0070] The controllable phase tuner 312 may include a single phase shifter positioned to change the phase of light in one pin (first pin 314 or second pin 316), or may include multiple phase shifters (each of which can be controlled independently). In some cases, the controllable phase tuner 312 includes multiple phase shifters, wherein at least one phase shifter is positioned to change the phase of light in the first pin 314, and at least one phase shifter is positioned to change the phase of light in the second pin 316. Additionally or alternatively, the controllable phase tuner 312 may include multiple phase tuners positioned to change the phase of light in one of these pins. For example, in Figure 3A In the variant of the 1×2 controllable switch 300 shown, the controllable phase tuner 312 includes: a first phase shifter 318 and a second phase shifter 320, each of which is positioned to change the phase of light in the first pin 314; and a third phase shifter 322, which is positioned to change the phase of light in the second pin 316.

[0071] Including multiple phase shifters allows the controllable phase tuner 312 to divide the tuning range across multiple phase shifters (i.e., the phase shift range required to address different output distributions across the measurement wavelengths of the 1×2 controllable switch 300). This can improve the speed at which the controllable phase tuner 312 can adjust the phase difference and / or reduce the losses associated with adjusting the phase difference. Additionally or alternatively, different phase shifters can be used to create the target phase difference at different times. Specifically, different types of phase shifters can have different trade-offs in speed and optical loss (e.g., thermo-optical phase shifters are generally lossless, but the phase change rate is slower compared to some electro-optical phase shifters where losses are proportional to the amount of phase added), and therefore different types of phase shifters can be used to balance speed and loss.

[0072] For example, a first phase shifter can initially provide a target phase shift at a first loss level. A second phase shifter can also be controlled to provide a target phase shift at a lower loss level than the first phase shifter, but this phase shift is achieved more slowly. Once the first phase shifter has provided the target phase shift, it can be controlled to reduce the phase shift it provides while the second phase shifter increases its provided phase shift. This increase and decrease can be controlled to maintain the target phase shift during this transition. Thus, a controllable switch can quickly provide a target phase shift and then gradually reduce the losses associated with providing the target phase shift.

[0073] In other variations, the controllable switch includes a 2×2 controllable switch. For example, Figure 3B A variation of the 2×2 controllable switch 324 is shown. The 2×2 controllable switch 324 is similar to the one described above relative to... Figure 3A The 1×2 controllable switch 300 (where similar components are labeled the same) differs in that the 2×2 controllable switch 324 includes a first input terminal 326 and a second input terminal 328 fed to the first 2×2 coupler 330 and the second 2×2 coupler 332, instead of a single input terminal 302 fed to the 1×2 coupler 308 and the 2×2 coupler 310. For example... Figure 3B As shown, the first 2×2 coupler 324 receives light from the first input terminal 326 and / or the second input terminal 328 as input, and uses the first pin 314 and the second pin 316 as output terminals. Similarly, the second 2×2 coupler 332 receives light from the first pin 314 and the second pin 316 as input, and uses the first output terminal 304 and the second output terminal 306 as output terminals.

[0074] Light received by either the first input terminal 326 or the second input terminal 328 of the 2×2 controllable switch 324 is split between the first pin 314 and the second pin 316 by the first 2×2 coupler 330. The second 2×2 coupler 332 receives light from the first pin 314 and the second pin 316 and couples the light to the first output terminal 304 and / or the second output terminal 306 (as opposed to...). Figure 3A (Described in more detail). A controllable phase tuner 312 (located between the first 2×2 coupler 330 and the second 2×2 coupler 332) selectively adjusts the phase difference between light in the first pin 314 and the second pin 316, as described above. Although the adjustable phase tuner 312... Figure 3B The first phase shifter 318, shown as having only a first phase shifter 318 positioned to change the phase of light in the first pin 314, is also described above. However, it should be understood that the adjustable phase tuner 312 can be configured as described above relative to the first phase shifter 314. Figure 3AThe 1×2 controllable switch 300 can be configured in any of the ways described. By adjusting the phase difference between the first pin 314 and the second pin 316, the 2×2 controllable switch 324 can acquire light received from one of its inputs (e.g., the first input 326 or the second input 328) and selectively route the light entirely to the first output 304, entirely to the second output 306, or simultaneously to both the first output 304 and the second output 306 (i.e., splitting the light between the outputs according to a target split ratio).

[0075] In some cases, the controllable switch can also be configured to tap off a portion of the light received by the controllable switch. This may be desirable in cases where multi-stage optical network switches are used to pass light to a wavelength-locked unit as described above. Figure 3C An example of such a 2×2 controllable switch 334 is shown. The 2×2 controllable switch 334 is configured to... Figure 3A The 2×2 controllable switch 334 is identical to the 2×2 controllable switch 310 (where similar components are labeled as identical), except that the 2×2 controllable switch 334 includes a tap 336 (e.g., an optical waveguide tap) that extracts a portion of the light from the pins of the controllable switch 334 into a separate waveguide 338. Waveguide 338 can then transmit the light to another part of the optical measurement system (e.g., a wavelength-locked unit as discussed herein). Although shown as a pin with a phase shifter ( Figure 3C The first pin 314 in the circuit is used to tap the light, but tap 336 can optionally tap from a pin that does not include a phase shifter. Figure 3C The second pin (316) in the circuit is used to tap the light.

[0076] Placing a tap to extract light from a pin of the controllable switch introduces a wavelength-dependent phase shift into that pin. The controllable phase tuner 312 can be controlled to account for this wavelength-dependent phase shift based on the wavelength of the light currently passing through the controllable switch, but this can increase the complexity of the control scheme used to operate the controllable switch. To address this issue, in some variations, the controllable switch can be configured to include two taps, such that each tap extracts a portion of light from the corresponding pin of the controllable switch.

[0077] Figure 3D An example of such a 2×2 controllable switch 340 is shown. The 2×2 controllable switch 340 is configured to... Figure 3CThe 2×2 controllable switch 340 is identical to the 2×2 controllable switch 334 (where similar components are labeled as identical), except that the 2×2 controllable switch 340 includes an additional tap 342 (e.g., an optical waveguide tap). A first tap 336 extracts a portion of the light traveling through a first pin 314 of the controllable switch 340 into a first decoupling waveguide 338, and a second tap 342 extracts a portion of the light traveling through a second pin 316 of the controllable switch 340 into a second decoupling waveguide 344. The first tap 336 and the second tap 342 can be configured to provide the same wavelength-dependent phase change in each of the first pin 314 and the second pin 316. For example, in some cases, the first tap 336 and the second tap 342 can be identical, such that these taps extract the same percentage of light from the first pin 314 and the second pin 316, respectively, and introduce the same wavelength-dependent phase change into the first pin 314 and the second pin 316.

[0078] First waveguide 338 and second waveguide 344 can transmit light to other parts of the optical measurement system (e.g., wavelength-locked units as discussed herein). For example, in some variations, first tap 336 and second tap 342 route light to a single component, such as a wavelength-locked unit. Depending on the design of the wavelength-locked unit, first waveguide 338 and second waveguide 344 can be formed to a separate input of the wavelength-locked unit, or they can be multiplexed or otherwise combined to form a single input of the wavelength-locked unit (e.g., light from first tap 336 and second tap 342 can be directed to a common detector of the wavelength-locked unit, such that the detector measures the light collected from both first tap 336 and second tap 342). In cases where light from first waveguide 338 and second waveguide 344 is combined, it may be desirable for one or both of these waveguides to include a controllable phase tuner (as described herein) that can be used to control the relative phase of the light between first waveguide 338 and second waveguide 344. In other variations, the first tap 336 and the second tap 342 route light to different parts of the optical measurement system. For example, the first tap 336 may route light to a wavelength-locked system, while the second tap 336 may route light to a second wavelength-locked system or a different component (such as part of the optical measurement system that performs calibration, initiates a process, or monitors system performance).

[0079] The number and arrangement of controllable switches in a multi-stage optical switching network depend, at least in part, on the desired number of inputs and outputs of the network. For example, Figure 4A portion of a variant of an optical measurement system 400 with a multi-level optical switching network 402 is shown, the multi-level optical switching network having one input 401 and four outputs 403A-403D. As shown, the optical measurement system 400 also includes a light source unit 404 and multiple emission groups 406A-406D, wherein each emission group is optically connected to a corresponding output of the multi-level optical switching network 402. Although not shown, the optical measurement system 400 may include the components described above relative to... Figures 1A to 2 Any other component of the optical measurement system (e.g., multiple detector groups, controller).

[0080] The light source unit 404 has a single output terminal that is optically connected to the input terminal 401 of the multi-stage optical switch network 402. The output terminal of the light source unit 404 is... Figure 4 Not separately labeled, and it should be understood, the optical measurement system 400 may optionally include additional components, such as those discussed above, between the output and input 401 of the multi-stage optical switching network 402. Figure 4 In a variation of the illustrated light source unit 404, the light source unit 404 includes multiple light sources (labeled 408-1 to 408-N) connected to a multiplexer 410, which combines the outputs of the multiple light sources into a common output (i.e., the output of the light source unit 404). Therefore, the light source unit 404 can output light generated by any of the multiple light sources 408-1 to 408-N to a multi-stage optical switching network 402. If each of the N light sources can emit a wavelength at least different from the other light sources, then the light source unit 404 can generate at least N different wavelengths of light.

[0081] The multi-stage optical switch network 402 includes a first stage 414 with a 1×2 controllable switch 416 and a second stage 418 with a first 1×2 controllable switch 420 and a second 1×2 controllable switch 422. The 1×2 controllable switch 416 of the first stage 414 receives light from an input terminal 401 (i.e., the input terminal 401 of the multi-stage optical switch network 402 acts as the input terminal of the 1×2 controllable switch 416) and outputs light to the second stage 418. Specifically, a first waveguide 424 connects the first output terminal of the 1×2 controllable switch 416 of the first stage 414 to the input terminal of the first 1×2 controllable switch 420 of the second stage 418. Similarly, a second waveguide 426 connects the second output terminal of the 1×2 controllable switch 416 of the first stage 414 to the input terminal of the second 1×2 controllable switch 422 of the second stage 418. The output terminal of the first 1×2 controllable switch 420 of the second stage 418 forms the first output terminal 403A and the second output terminal 403B of the multi-stage optical switch network 402, and the output terminal of the second 1×2 controllable switch 422 of the second stage 418 forms the third output terminal 403C and the second output terminal 403D of the multi-stage optical switch network 402. In some cases, one or more of the 1×2 controllable switches include, for example, relative to... Figure 3C and Figure 3D The aforementioned tap or tap group (not shown) can be used to tap out a portion of the light received by the multi-stage optical switch network 402 (e.g., for wavelength stabilization / locking as discussed above). If the first-stage 1×2 controllable switch 416 includes a tap, that tap will be able to receive light generated by the light source unit 404, regardless of how the multi-stage optical switch network 402 is configured to route light to its outputs 403A-403D.

[0082] Figure 4The multi-stage optical switch network 402 depicted has four potential output configurations and can be controlled to selectively route light simultaneously to one, two, three, or four of the outputs 403A-403D (and associated transmitter groups 406A-406D). For example, in order to route light from input 401 only to the first output 403A and the first transmitter group 406A (i.e., in an output configuration with one simultaneous output), the 1×2 controllable switch 416 of the first stage 414 is controlled to route the input light only to the first waveguide 424 (and therefore only to the first 1×2 controllable switch 420 of the second stage 418). The first 1×2 controllable switch 420 of the second stage 418 is similarly controlled to route the light it receives only to the first output 403A. A multi-stage optical switch network can be similarly controlled to selectively route light with the output configuration of a single simultaneous output, but to different groups of outputs (only to the second output 403B, only to the third output 403C, or only to the fourth output 403D) and thus to different corresponding transmission groups (only to the second transmission group 406B, only to the third transmission group 406C, or only to the fourth transmission group 406D).

[0083] To simultaneously route the input light to all four outputs 403A-403D and all four transmitter groups 406A-406D (i.e., in a four-simultaneous output configuration), the 1×2 controllable switch 416 of the first stage 414 is controlled to split the input light between the first waveguide 424 and the second waveguide 426. The first 1×2 controllable switch 420 of the second stage 418 is controlled to split the light it receives (i.e., via the first waveguide 424) between the first output 403A and the second output 403B. Similarly, the second 1×2 controllable switch 422 of the second stage 418 is controlled to split the light it receives (i.e., via the second waveguide 426) between the third output 403C and the fourth output 403D. If all controllable switches uniformly split the light between their outputs, then all four outputs 403A-403D (and therefore all four emission groups 406A-406D) will receive an equal amount of light (however, it should be understood that different splitting ratios can be used to produce a non-uniform distribution of light between the four outputs 403A-403D and the corresponding emission groups 406A-406D). A similar principle can be applied to selectively routing light to two or three of the outputs 403A-403D simultaneously (i.e., configuring the outputs of two or three simultaneous outputs respectively).

[0084] Figure 5Another variation of the optical measurement system 500 is shown, which includes a multi-stage optical switching network 502 having two input terminals 503A, 501B and four output terminals 501A-503D. As shown, the optical measurement system 500 also includes a light source unit 504 and multiple emission groups 506A-506D, each emission group being optically connected to a corresponding output terminal 503A-503D of the multi-stage optical switching network 502. Although not shown, the optical measurement system 500 may include the components described above relative to... Figures 1A to 2 Any other component of the optical measurement system (e.g., multiple detector groups, controller).

[0085] The light source unit 504 has two output terminals optically connected to the input terminals of the multi-level optical switch network 502. Specifically, the first light source unit 504 has a first output terminal optically connected to a first input terminal 501A of the multi-level optical switch network 502 and a second output terminal optically connected to a second input terminal 501B of the multi-level optical switch network 502. The first and second output terminals of the light source unit 504 are located at... Figure 5 Unless otherwise specified, and it should be understood that the optical measurement system 500 may optionally include additional components, such as those discussed above, between any output of the light source unit 504 and the input of its corresponding multi-stage optical switching network 502.

[0086] The light source unit 504 has one or more light sources optically connected to each of its output terminals. Figure 5 In a variation of the illustrated light source unit 504, the light source unit 504 includes a first plurality of light sources 508-1 to 508-N connected to a first multiplexer 510 and a second plurality of light sources 512-1 to 512-M connected to a second multiplexer 514. The first multiplexer 510 combines the outputs of the first plurality of light sources into a first common output (i.e., the first output of the light source unit 504), and the second multiplexer 514 combines the outputs of the second plurality of light sources into a second common output (i.e., the second output of the light source unit 504). Therefore, the light source unit 504 can output light from any of the first plurality of light sources and the second plurality of light sources to a multi-stage optical switching network 502. If each of the N light sources in the first plurality of light sources and the M light sources in the second plurality of light sources can emit at least one wavelength that is unique relative to the other light sources, then the light source unit 504 can generate light of at least N+M different wavelengths. Splitting the light sources among different multiplexers allows the light source unit to generate a wider range of wavelengths while reducing the optical loss associated with multiplexed light sources.

[0087] The multi-stage optical switch network 502 includes a first stage 515 with a 2×2 controllable switch 516 and a second stage 518 with a first 1×2 controllable switch 520 and a second 1×2 controllable switch 522. A first input terminal 501A and a second input terminal 501B of the multi-stage optical switch network 502 serve as input terminals to the 2×2 controllable switch 516. Therefore, the 2×2 controllable switch 516 can receive light from either input terminal and route the light to the second stage 518. Specifically, a first waveguide 524 connects the first output terminal of the 2×2 controllable switch 516 to the input terminal of the first 1×2 controllable switch 520 in the second stage 518. Similarly, a second waveguide 526 connects the second output terminal of the 2×2 controllable switch 516 to the input terminal of the second 1×2 controllable switch 522 in the second stage 518. The output terminal of the first 1×2 controllable switch 520 of the second stage 518 forms the first output terminal 503A and the second output terminal 503B of the multi-level optical switch network 502, and the output terminal of the second 1×2 controllable switch 522 of the second stage 518 forms the third output terminal 503C and the second output terminal 503D of the multi-level optical switch network 502.

[0088] In some cases, one or more of the controllable switches in the multi-level optical switch network 502 include, for example, those relative to... Figure 3C The aforementioned tap. For example, in Figure 5 In the variant shown, the 2×2 controllable switch 516 includes a tap 528. As described above, the tap 528 can tap off a portion of the light received by the 2×2 controllable switch 516 and can route that light to a wavelength-locking unit 530, as discussed herein. Because all light entering the multi-stage optical switch network 502 passes through the 2×2 controllable switch 516, the tap 528 allows the optical measurement system 500 to use the wavelength-locking unit 530 to stabilize light of any wavelength generated by the light source unit 504 and received by the multi-stage optical switch network 502.

[0089] It should be understood that, in other cases, the 2×2 controllable switch 516 includes multiple taps, such as those described herein relative to... Figure 3D As described above. In these cases, the 2×2 controllable switch 516 includes a second tap 538, such that taps 528 and 538 extract light from different pins of the 2×2 controllable switch 516. The second tap 538 can route light from the 2×2 controllable switch 516 to the second wavelength locking unit 540, as... Figure 5 As shown, routing is to the first wavelength locking unit 530, or to another component such as described herein.

[0090] The multi-stage optical switch network 502 has four potential output configurations and can be controlled to receive light from either the first input 501A or the second input 501B, while selectively routing the light to one, two, three, or four of the outputs 503A-503D (and associated transmitter groups 506A-506D). For example, to route light from the first input 501A to only the first output 503A and the first transmitter group 506A, the 2×2 controllable switch 516 is controlled to route the light received from the first input 501A only to the first waveguide 524. Similarly, the first 1×2 controllable switch 520 of the second stage 518 is similarly controlled to route the light it receives only to the first output 503A. Alternatively, to route light from the second input 501B, the 2×2 controllable switch 516 can be switched to alternatively route the light received from the second input 501B only to the first waveguide 524. In this way, the multi-stage output switching network 502 can obtain light from any light source from the light source unit 504 and route it (via the first input 501A or the second input 501B) to the target group output and the corresponding emission group (first output 503A and first emission group 506A, second output 503B and second emission group 506B, third output 503C and third emission group 506C, or fourth output 503D and fourth emission group 506D) in a single output configuration.

[0091] To simultaneously route the light received from the light source unit 504 to all four output terminals 503A-503D and all four emission groups 506A-506D (i.e., in a configuration with four simultaneous output terminals), a 2×2 controllable switch 516 is controlled to simultaneously split the light received from one input terminal (either the first input terminal 501A or the second input terminal 501B) between the first waveguide 524 and the second waveguide 526. A first 1×2 controllable switch 520 of the second stage 518 is controlled to simultaneously split the light it receives (i.e., via the first waveguide 524) between the first output terminal 506A and the second output terminal 503B (and therefore the first emission group 503A and the second emission group 506B). Similarly, a second 1×2 controllable switch 522 of the second stage 518 is controlled to simultaneously split the light it receives (i.e., via the second waveguide 526) between the third output terminal 506C and the fourth output terminal 503D (and therefore the third emission group 503C and the fourth emission group 506D). If all controllable switches uniformly divide the light among their outputs, then all four outputs 503A-503D (and all four emitter groups 506A-506D) will receive an equal amount of light (however, it should be understood that different division ratios can be used to create a non-uniform distribution of light among the four outputs 503A-503D). A similar principle can be applied to selectively routing light simultaneously to two or three of the outputs 503A-503D (i.e., configuring the outputs of two or three simultaneous outputs respectively).

[0092] Figure 6 A further variation of the optical measurement system 600 is shown, comprising a multi-stage optical switching network 602 having four inputs 601A-601D and four outputs 603A-603D. As shown, the optical measurement system 600 also includes a light source unit 604 and multiple emission groups 606A-606D, each emission group being optically connected to a corresponding output of the multi-stage optical switching network 602. Although not shown, the optical measurement system 600 may include the components described above relative to... Figures 1A to 2 Any other component of the optical measurement system (e.g., multiple detector groups, controller).

[0093] The light source unit 604 has four output terminals optically connected to the input terminals of the multi-level optical switch network 602. Specifically, the first light source unit 604 has a first output terminal optically connected to a first input terminal 601A of the multi-level optical switch network 602, a second output terminal optically connected to a second input terminal 601B, a third output terminal optically connected to a third input terminal 601C, and a fourth output terminal optically connected to a fourth input terminal 601D. The output terminals of the light source unit 604 are located at... Figure 6Unless otherwise specified, and it should be understood that the optical measurement system 600 may optionally include additional components, such as those discussed above, between any output of the light source unit 604 and the input of its corresponding multi-stage optical switching network 602.

[0094] The light source unit 604 has one or more light sources optically connected to each of its output terminals. Figure 6 In a variant of the illustrated light source unit 604, the light source unit 604 includes a first plurality of light sources 608-1 to 608-N connected to a first multiplexer 610, a second plurality of light sources 612-1 to 612-M connected to a second multiplexer 614, a third plurality of light sources 616-1 to 616-P connected to a third multiplexer 618, and a fourth plurality of light sources 620-1 to 620-Q connected to a fourth multiplexer 621. Each of these multiplexers combines the outputs of its associated plurality of light sources into a common output (collectively forming the four outputs of the light source unit 604). Therefore, the light source unit 604 can output light from any of the four plurality of light sources. If each of the four plurality of light sources can emit light of at least one wavelength that is unique relative to the other light sources, then the light source unit 604 can generate at least N+M+P+Q different wavelengths of light. Splitting the light sources among different multiplexers allows the light source unit to generate a wider range of wavelengths while reducing the optical loss associated with multiplexed light sources.

[0095] The multi-stage optical switch network 602 includes a first stage 622 having a first 2×2 controllable switch 624 and a second 2×2 controllable switch 626, and a second stage 628 having a first 2×2 controllable switch 630 and a second 2×2 controllable switch 632. Each of these controllable switches has two inputs and two outputs, and can selectively route light received from one of the inputs to either output or both outputs simultaneously, as described above. The first input 601A and the second input 601B of the multi-stage optical switch network 602 serve as inputs to the first 2×2 controllable switch 624 of the first stage 622. Similarly, the third input 601C and the fourth input 601D of the multi-stage optical switch network 602 serve as inputs to the second 2×2 controllable switch 626 of the first stage 622. Therefore, each input of the multi-stage optical switch network 602 is routed to either the first 2×2 controllable switch 624 or the second 2×2 controllable switch 626 of the first stage 622.

[0096] Each of the controllable switches in the first stage 622 routes optical light to one or both of the controllable switches in the second stage 628. Specifically, the first waveguide 634 connects the first output of the first 2×2 controllable switch 624 in the first stage 622 to the first input of the first 2×2 controllable switch 630 in the second stage 628. The second waveguide 636 connects the second output of the first 2×2 controllable switch 624 in the first stage 622 to the first output of the second 2×2 controllable switch 632 in the second stage 628. Similarly, the third waveguide 638 connects the first output of the second 2×2 controllable switch 626 in the first stage 622 to the second input of the first 2×2 controllable switch 630 in the second stage 628. The fourth waveguide 640 connects the second output of the second 2×2 controllable switch 626 in the first stage 622 to the second output of the second 2×2 controllable switch 632 in the second stage 628. The output terminal of the first 2×2 controllable switch 630 of the second stage 628 forms the first output terminal 603A and the second output terminal 603B of the multi-stage optical switch network 602, and the output terminal of the second 2×2 controllable switch 632 of the second stage 628 forms the third output terminal 603C and the fourth output terminal 603D of the multi-stage optical switch network 602.

[0097] In some cases, one or more of the controllable switches in the multi-level optical switch network 602 include, for example, those relative to... Figure 3C The aforementioned tap. For example, in Figure 6 In the illustrated variant, the first 2×2 controllable switch 624 of the first stage 622 includes a first tap 642, and the second 2×2 controllable switch 626 of the first stage 622 includes a second tap 644. The first tap 642 taps out a portion of the light received by the first 2×2 controllable switch 624 of the first stage 622 (e.g., from a light source among a first plurality of light sources or a second plurality of light sources), and this light can be routed to a first wavelength locking unit 646, as discussed above. Similarly, the second tap 644 taps out a portion of the light received by the second 2×2 controllable switch 626 of the first stage 622 (e.g., from a light source among a third plurality of light sources or a fourth plurality of light sources), and this light can be routed to a second wavelength locking unit 648. Although the optical measurement system 600 in… Figure 6The image is shown as having two separate wavelength-locked units, but in other variations, the first tap 642 and the second tap 644 route light to a single wavelength-locked unit (e.g., light from the first tap 642 and the second tap 644 can be multiplexed into a single waveguide). Because all light entering the multi-stage optical switching network 602 passes through either of the controllable switches in the first stage, the first tap 642 and the second tap 644 together allow the optical measurement system 600 to stabilize any wavelength generated by the light source unit 604 and received by the multi-stage optical switching network 602. It should be understood that either or both of the first 2×2 controllable switch 624 and the second 2×2 controllable switch 626 may include attachment taps, such as those described herein with respect to… Figure 3D As stated above.

[0098] The multi-stage optical switch network 602 has four potential output configurations and can be controlled to receive light received from any of the four inputs 601A-601D and simultaneously route it to one, two, three, or four of the outputs 603A-603D (and their associated transmission groups 606A-606D). For example, to route light from the first input 601A or the second input 601B only to the first output 603A and the first transmission group 606A (i.e., in an output configuration with one simultaneous output), the first 2×2 controllable switch 624 of the first stage 622 is controlled to route light received from the selected input only to the first waveguide 634. Similarly, the first 2×2 controllable switch 630 of the second stage 628 is controlled to route light received from the first waveguide 634 only to the first output 603A (and thus to the first transmission group 606A). To alternatively route light from the third input 601C or the fourth input 601D, the second 2×2 controllable switch 626 of the first stage 622 is controlled to route light received at that input only to the third waveguide 638. The first 2×2 controllable switch 630 of the second stage 628 is controlled to route light received from the third waveguide 638 only to the first output 603A. In this way, the multi-stage output switch network 602 can acquire light from any light source of the light source unit 604 and route it to the first output 603A and the first emission group 606A. The multi-stage optical switch network 602 can also be controlled to route light from any light source of the light source unit 604 in a single output configuration to any other group output and the corresponding set of emission groups (the second output 603B and the second emission group 606B, the third output 603C, or the fourth output 603D). A similar principle can be applied to selectively routing light simultaneously to a group of outputs, including two, three, or four of the outputs in the 603A-603D series (i.e., with outputs of two, three, or four simultaneous outputs).

[0099] For the multi-stage optical switch network described herein, how each controllable switch is controlled depends on which inputs and outputs of the multi-stage optical switch network will receive and output light, respectively, and what wavelengths of light the multi-stage optical switch network receives. Therefore, when any of these parameters changes, the control of the switches will be modified to achieve the desired output. Each controllable switch will have its own default splitting behavior (i.e., when it is not actively controlled), and thus the multi-stage optical switch network will have its own default routing configuration based on the default behavior of its controllable switches. Controllable switches can be designed to achieve the desired routing configuration of the multi-stage optical switch network. For example, in some cases, the default switching behavior of the controllable switches is selected to minimize the average loss associated with controlling the multi-stage optical switch network to route each wavelength of the measurement wavelengths during a predetermined measurement sequence. In other cases, it may be desirable to minimize the average time required for the multi-stage optical switch network to change from its default routing configuration to another set of routing configurations (which could be a subset of all routing configurations used during a predetermined measurement sequence).

[0100] It should be understood that the principle of the aforementioned multi-stage optical switch network can be extended to provide a network for routing any combination of inputs and outputs. As the number of inputs and / or outputs increases, the multi-stage optical switch network can include additional stages and / or controllable switches within each stage to provide different possible routing paths between each input and multiple outputs. For example, to accommodate more than four inputs and / or more than four outputs, the multi-stage optical switch network can be configured to include three or more stages, and at least one of these stages can include at least three controllable switches. Therefore, these multi-stage optical switch networks can be used with a wide range of possible optical measurement system designs to achieve a series of different output configurations.

[0101] As described above, the optical measurement system described herein can be used to measure one or more properties of a sample. Specifically, the optical measurement system can execute a sequence of measurements to generate multiple output signals that can be used to determine one or more properties of the sample. These measurement sequences are repeatable, wherein multiple output signals associated with a successive measurement sequence are used together to determine one or more properties of the sample or to perform a successive determination of one or more properties of the sample at later points in time. One or more parameters of the measurement sequence can be updated before executing the successive measurement sequence, as discussed in more detail below.

[0102] Each measurement sequence comprises multiple individual measurements, each generating at least one output signal (these together form the multiple output signals of the measurement sequence). Each individual measurement is performed at a corresponding wavelength (i.e., light is generated and emitted from the optical measurement system at the corresponding wavelength during a portion of the individual measurement), such that at least one individual measurement is performed for each of the multiple wavelengths. The results of the individual measurements of the measurement sequence (i.e., the multiple output signals) are used to derive one or more properties of the sample (e.g., using spectroscopic analysis techniques). As will be readily understood by those skilled in the art, optical measurement systems facilitate a wide range of analytical techniques; therefore, the individual techniques used to derive properties from a sample using measurements performed at multiple different wavelengths will not be discussed herein.

[0103] Figure 7 A method 700 for performing a measurement sequence using multiple different wavelengths is described. This method 700 can be performed by any of the optical measurement systems described herein. Initially, method 700 includes selecting multiple wavelengths at step 702. These multiple wavelengths will be the wavelengths used to measure the sample and can be selected based on the expected sample to be measured and one or more desired properties to be determined from the sample. For example, when an optical measurement system having a light source unit as described above is used to perform the measurement sequence, the multiple wavelengths can be a subset of wavelengths that the light source unit is capable of generating. Different subsets of these wavelengths can be selected for different measurement scenarios. In some cases, selecting the multiple wavelengths includes performing a set of preliminary measurements (e.g., using one or more wavelengths) to generate a set of preliminary output signals, and using this set of preliminary output signals to select the multiple wavelengths. For example, preliminary measurements may allow for initial characterization or estimation of certain properties of the sample, which can be used to select the multiple wavelengths.

[0104] Once the multiple wavelengths have been selected, they are divided into groups at step 704. Each group (and therefore each wavelength within a group) is associated with a different corresponding output configuration. The number of groups may depend on how many different output configurations the measurement sequence requires, and it is not necessary to utilize every output configuration that can be implemented by a given optical measurement system. For example, in the case of an optical measurement system with four emission groups, the multiple wavelengths may be divided into two, three, or four different groups, each associated with a different corresponding output configuration. In some cases, assigning a given wavelength to a group may be based on which noise source is expected to limit the SNR of individual measurements performed at that wavelength.

[0105] For example, in some cases, it may be desirable to maximize the SNR of measurements performed at each wavelength. Regardless of the output configuration, some wavelengths may be limited by fundamental noise. These wavelengths can be assigned to the group with the finest output configuration (i.e., where the light is split across the fewest number of emission groups), which in turn improves the SNR of these wavelengths. As a non-limiting example, these wavelengths can be assigned to a group with an output configuration having one simultaneous output, such that only one emission group receives light at a time and receives all the light generated by a given light source (without any losses associated with the optical measurement system).

[0106] Conversely, other wavelengths can be limited by different noise sources (e.g., coherent noise) regardless of the output configuration of the measurement. These wavelengths can be assigned to the group with the coarsest output configuration (i.e., where light is simultaneously split across most emission groups), which saves time and power compared to performing individual measurements with higher output configurations (i.e., a larger number of simultaneous outputs). As a non-limiting example, these wavelengths can be assigned to a group with an output configuration of four simultaneous outputs. Each emission group receives less light than a measurement at that emission group with an output configuration of one simultaneous output, but still results in a similar SNR. By simultaneously splitting light across multiple emission groups, such measurements reduce the time required to measure all emission groups and save power compared to multiple measurements for a finer output configuration.

[0107] Other wavelengths may be limited by fundamental noise in some output configurations, but by other noise sources (e.g., coherent noise) in others. These wavelengths can be assigned to groups corresponding to output configurations where the measurement will no longer be limited by fundamental noise. For example, for a measurement performed with four simultaneous outputs, the wavelength may be limited by fundamental noise, but for a measurement performed with two simultaneous outputs, the wavelength may be limited by fundamental noise. In these cases, it may be necessary to assign the wavelength to a group corresponding to the two simultaneous outputs (which still saves time and power compared to a separate measurement with one simultaneous output). It should be understood that this is merely an illustrative example, and these wavelengths can be assigned to different groups to achieve any desired trade-offs in SNR, power consumption, and time requirements for performing the measurements described herein.

[0108] In some cases, each of the multiple wavelengths has a default group (among the multiple groups) that is assigned for a given measurement sequence. In other cases, one or more parameters associated with the sample can be used to divide the multiple wavelengths into the multiple groups (which may result in deviations from the default behavior). For example, certain properties of the sample (e.g., scattering or absorption coefficients, the material type of the sample) can be used to divide the wavelengths. In some cases, this information can be known in advance (e.g., manually entered before measuring the sample, or saved from previous measurements of the same sample).

[0109] Additionally or alternatively, a set of preliminary measurements may be used to generate a corresponding group output signal for classifying the plurality of wavelengths into the plurality of groups. When performing a set of preliminary measurements (“first set of preliminary measurements”) as part of selecting the plurality of wavelengths, a set of preliminary corrections (“second set of preliminary measurements”) for classifying the plurality of wavelengths may include some or all of the measurements in the first set of preliminary measurements. Additionally or alternatively, the second set of preliminary measurements includes one or more additional preliminary measurements. For example, the output signal of the preliminary measurements may be used to determine a measure of optical power (i.e., signal strength) at one or more detectors in one or more detector groups associated with one or more emission groups. This measure of optical power (e.g., optical power measured by a single detector, the average of optical power measured by multiple different detectors, or other combinations) may be used to determine which group of the plurality of wavelengths the wavelength is assigned to. For example, if the measure is below a predetermined threshold for a given wavelength, then the wavelength may be assigned to a group with a finer output configuration than its default group. It should be understood that each wavelength measured using the preliminary measurements (which may collectively be only a subset of the plurality of wavelengths) may have its own set of thresholds for determining which group the wavelength should be assigned to.

[0110] For each of the plurality of wavelengths, method 700 includes performing a set of individual measurements of the sample for each of the plurality of wavelengths at step 706, wherein each set of individual measurements is performed with an output configuration corresponding to that wavelength. A corresponding set of output signals is generated for each set of individual measurements, thus the measurement sequence generates a plurality of output signals consisting of these corresponding sets of output signals.

[0111] For example, the plurality of wavelength groups includes a first group associated with a first output configuration and a second group associated with a second output configuration. For each wavelength in the first group, a corresponding group measurement is performed in the first output configuration (e.g., performing a first group measurement of the sample for a first wavelength in the first group). This includes: generating light of that wavelength (e.g., the first wavelength), emitting the generated light from a set of emission group correspondences selected from the plurality of emission groups (the corresponding group having a first number of emission groups corresponding to the first output configuration), and measuring the returned light received during the emission of the generated light using a set of detector group correspondences selected from the plurality of detector groups (the corresponding group having a first number of detector groups).

[0112] Similarly, for each wavelength in the second group, the corresponding group measurement is performed in a first output configuration (e.g., performing a second group measurement of the sample for a second wavelength in the second group). This includes: generating light at that wavelength (e.g., the second wavelength), emitting the generated light from a set of emission group correspondences selected from the plurality of emission groups (the corresponding group has a second number of emission groups corresponding to the second output configuration), and measuring the returned light received during the emission of the generated light using a set of detector group correspondences selected from the plurality of detector groups (the corresponding group has a second number of detector groups).

[0113] In some cases, this set of individual measurements comprises multiple measurements with different sets of emission group correspondences and different corresponding group detectors. In the example just discussed above, the first set of measurements performed at the first wavelength may include multiple measurements, each with a different unique set of emission groups (while still maintaining the first output configuration). Similarly, since each emission group is associated with a corresponding set of detectors, these multiple measurements can each use a different unique set of detectors.

[0114] Additionally or alternatively, the individual measurements for a particular wavelength are performed jointly using each emission group, with at least one measurement executed. Specifically, performing individual measurements with a given output configuration involves emitting light into the sample from multiple emission groups (and emission sites associated with these emission groups), where the number of emission groups corresponds to the given output configuration. For example, if the optical measurement system has four emission groups, then if the light is split simultaneously among all four emission groups, the individual measurements for that wavelength may include a single individual measurement. If the light is split simultaneously among two emission groups or among three emission groups, then the individual measurements for another wavelength may include two individual measurements. If the light is sent to only one emission group at a time (i.e., one measurement per emission group), then the individual measurements for yet another wavelength may include four individual measurements. In this way, the measurement sequence ensures that each of the multiple emission groups is used to measure all wavelengths among the multiple wavelengths.

[0115] In some of these variations, the individual measurement for a given wavelength may optionally include individual measurements for each unique group of emission groups having a corresponding output configuration (i.e., each of the possible sub-configurations of the output configuration). For example, when the optical measurement system has four emission groups, there exist a unique group of emission groups in which light is simultaneously split among all four emission groups (i.e., the output configuration of four simultaneous outputs), six unique group of emission groups in which light is simultaneously split among two emission groups (i.e., the output configuration of two simultaneous outputs), four unique group of emission groups in which light is simultaneously split among three emission groups (i.e., the output configuration of three simultaneous outputs), and four unique group of emission groups in which light is routed to only a single emission group (i.e., the output configuration of one simultaneous output). In other words, these output configurations have one sub-configuration, six sub-configurations, four sub-configurations, and four sub-configurations, respectively.

[0116] When light is emitted by one or more emission groups for a given individual measurement, one or more detector groups corresponding to the emission groups measure the light received by their associated detectors. Each detector can provide its own output signal, so a given individual measurement will produce one or more output signals (i.e., the outputs of the detectors in the detector groups used during that measurement). Because the measurement sequence performs a set of individual measurements for each wavelength, the method will generate a set of output signals for each wavelength. Additionally, in variations of the measurement sequence that measure each wavelength at each emission group, the method will correspondingly generate a set of output signals for each emission group at each wavelength. At step 708, the results of the measurement sequence (i.e., using the multiple sets of output signals generated from the individual measurements) can be used to determine one or more properties of the sample.

[0117] In some cases, such as as shown in step 710, the method may optionally update the plurality of groups to reassign at least one wavelength to a different group (and thereby associate the reassigned wavelength with a different output configuration before performing a subsequent measurement sequence). For example, for a given wavelength, the output signal of that group, generated by individual measurements performed at that wavelength, can be analyzed to determine whether that wavelength should be assigned to a different group with different output configurations. For example, if a measure of optical power derived from one or more output signals meets certain predetermined criteria for that wavelength (e.g., above a threshold, below a threshold), the wavelength can be assigned to a different default group for future measurement sequences. This allows the optical measurement system to tailor its measurement techniques for a range of samples with a range of different properties, such as when a measurement at a wavelength is expected to be limited by fundamental noise but actually by coherent noise.

[0118] While the method 700 described above discusses performing a measurement sequence comprising a set of individual measurements for each of a plurality of wavelengths, it should be understood that various individual measurements can be performed in any suitable order. In some cases, it may be desirable to divide the measurement sequence into multiple subsequences, where each subsequence includes the performance of consecutive measurements at a common wavelength among the plurality of wavelengths. In other words, individual measurements are grouped according to wavelength so that all measurements in a set of individual measurements for a particular wavelength are performed sequentially before measurements begin using another wavelength.

[0119] In other cases, it may be desirable to group measurements according to a set of emission groups. Each of these multiple subsequences comprises successive measurements performed at different wavelengths for the same emission group. Each subsequence has a corresponding group of wavelengths (i.e., the group of wavelengths from which the measurement of that emission group is taken) within these multiple wavelengths. In other words, all measurements for a given emission group (and therefore with its given output configuration or subconfiguration) are performed before moving to another emission group (which may include a different output configuration or a different subconfiguration). This may be desirable when switching between wavelengths is faster than switching between emission groups.

[0120] Figure 8 A measurement sequence 800 is shown. For illustrative purposes, the multiple wavelengths are divided into two groups and performed using an optical measurement system with four emission groups. The first group (“Group A”) has an output configuration with one simultaneous output, such that individual measurements using these wavelengths are routed to a single emission group. Figure 8 In the variant shown, the group-specific measurements for each wavelength in group A comprise a total of four measurements: one measurement for each emission group (labeled "Emission Group A-1" to "Emission Group A-4"). The second group ("Group B") has an output configuration with four simultaneous outputs, such that the individual measurements using these wavelengths are simultaneously split across all four outputs ("Emission Group B-1").

[0121] The measurement sequence shown here is divided into emission groups, such that at step 802, a first subsequence is performed, which includes individual measurements for each wavelength in group A at the first emission group (emission group A-1). At step 804, a second subsequence is performed, which includes individual measurements for each wavelength in group A at the second emission group (emission group A-2). At step 806, a third subsequence is performed, which includes individual measurements for each wavelength in group B, where the light is split among the four emission groups (emission group B-1). At step 808, a fourth subsequence is performed, which includes individual measurements for each wavelength in group A at the third emission group (emission group A-3). Finally, at step 810, a fifth subsequence is performed, which includes individual measurements for each wavelength in group A at the fourth emission group (emission group A-4). The first through fifth subsequences together perform all measurements of the measurement sequence, including four individual measurements for each wavelength in group A and one individual measurement for each wavelength in group B. It should be understood that the order of these subsequences is for illustrative purposes only, and the number and order of the subsequences can be determined at least in part by the number of groups and how many unique group emission groups are measured for each group.

[0122] As described above, a single measurement involves emitting light from a set of emission groups in a predetermined output configuration and measuring the light using a set of detectors corresponding to that set of emission groups to generate a set of output signals. It should be understood that additional steps may be associated with the single measurement. For example, when a multi-stage optical switching network is used to route light of a given wavelength to a specific set of emission groups (e.g., each measurement in the first set of measurements of the first wavelength described above), the single measurement may include a setup step in which the multi-stage optical switching network is reconfigured for this routing operation. Additionally or alternatively, a wavelength locking step may be used to set and stabilize the wavelength of the emitted light before measuring the light using the detector groups. Additionally or alternatively, the single measurement may include a background measurement in which background light is measured by one or more detector groups when the emission groups do not emit light simultaneously (e.g., before the emission of the generated light). These background measurements allow measurement corrections to account for detector dark current, stray light, and / or ambient light present during sample measurement.

[0123] Any optical measurement system described in this article can be used to perform the above-mentioned... Figure 7 and Figure 8The measurement sequence is described. In these cases, a light source unit can be used to generate each of the multiple wavelengths, and the light is provided to a multi-stage optical switching network via one or more outputs of the light source unit. For each individual measurement, the multi-stage optical switching network is controlled to route the light of the generated wavelength between one of its inputs (corresponding to the output of the light source unit that is outputting light) to a selected emission group. A detector group associated with the selected emission group measures the light during the measurement and generates an output signal for determining one or more properties of the sample being measured.

[0124] Figure 9 A timing diagram of a portion of measurement sequence 900 and exemplary steps associated with individual measurements of measurement sequence 900 are depicted. Measurement sequence 900 can be performed using an optical measurement system including a light source unit, multiple detector groups, and a multi-stage optical switching network that selectively routes light to multiple emission groups, as discussed in more detail above. Figure 9 In the variant shown, this portion of measurement sequence 900 involves a set of N wavelengths, each of which is measured individually at M different sets of emission groups (e.g., M different subsequences of N individually measured). Figure 9 A subset of these measurements is described, including: a first separate measurement 902, wherein a first wavelength (“λ-1”) is measured for a first group of emitters (“L-1”); a second separate measurement 904, wherein a second wavelength (“λ-2”) is measured for the first group of emitters; and a third separate measurement 906, wherein an Nth wavelength (“λ-1”) is measured for the first group of emitters. Similarly, Figure 9 A fourth separate measurement 908 is depicted, in which a first wavelength is measured for the Mth emission group (“LM”); a fifth separate measurement 910, in which a first wavelength is measured for the Mth emission group; and a sixth separate measurement 912, in which a Nth wavelength is measured for the Mth emission group.

[0125] Using the first individual measurement 902 as an example, each individual measurement includes a setup step (labeled "Setting L-1λ-1" for measurement 902). During this step, the multi-stage optical switching network is configured (i.e., by controlling the individual switches of the multi-stage optical switching network) to route the optical wavelength (i.e., λ-1) from the input of the network corresponding to that wavelength to the output corresponding to the selected group of emitters (i.e., the first group of emitters L-1). It should be understood that the time required to set the multi-stage optical switching network to the desired routing configuration may depend on the previous routing configuration. As mentioned above, in some cases, adjusting the multi-stage optical switching network to accommodate a new wavelength (while maintaining the same group of emitters) may be faster than switching between different groups of emitters, as indicated by the shorter setup step in the second individual measurement 904 (labeled "Setting L-1λ-2" for measurement 904). Once the setup step is complete, the multi-stage optical switching network can remain in this routing configuration (labeled "Maintaining L-1λ-1" for measurement 902) during the sample measurement.

[0126] During sample measurement, the light source unit generates light at the wavelength (i.e., λ-1) required for the measurement, which is labeled “λ-1 measurement” for measurement 902. Since wavelength deviations in the generated light can adversely affect the accuracy of the measurement, it may be desirable to ensure that the light source unit has reached a threshold level of wavelength accuracy before measuring the sample. Therefore, a separate measurement before measuring the sample may include a wavelength locking step (labeled “λ-1 locking” for measurement 902). During the wavelength locking step, the light source unit generates light and tunes the wavelength (e.g., via the wavelength locking unit as described above) until the desired wavelength (i.e., λ-1) is achieved (and in some cases, has threshold level stability). It should be understood that the wavelength locking step can be performed at any suitable time relative to the setup step of the multi-stage optical switching network. However, in some cases, it is desirable that the wavelength locking step and the setup step occur at least partially simultaneously, which can save time by allowing wavelength locking and setup to occur concurrently.

[0127] While the light source unit is generating light (i.e., during the λ-1 measurement step) and the multi-stage optical switch network is configured to output the generated light to the desired emission group (i.e., during the L1-λ-1 holding step), a set of detectors corresponding to that emission group will measure the light it receives during the emission of the generated light from that emission group (marked as "L-1 bright" in measurement 902). The duration of the sample measurement is defined by the amount of time during which the emission group and the detector set are activated simultaneously to measure the light. The detector set can output a corresponding set of output signals corresponding to the sample measurement.

[0128] Additionally, in some variations, the standalone measurement may include a background measurement (labeled "L-1 dark" for measurement 902), wherein the detector group (i.e., the detector group corresponding to the L-1 emission group) measures the light incident on the light source unit when the light source unit does not actively generate light. This detector group can output a set of output signals corresponding to the background measurement, which, together with the output signals corresponding to the sample measurement, can be used to calculate one or more properties of the sample (e.g., by performing dark signal correction on the output signals from the sample measurement). While the background measurement can be performed before or after the sample measurement, in some cases (such as...) Figure 9 As shown in the diagram, it may be desirable to perform at least a portion of the background measurements simultaneously with the setup steps of the multi-stage optical switch network. This saves time because the background measurements can be performed while the optical measurements are being prepared for sample measurement.

[0129] The foregoing description uses specific nomenclature to provide a thorough understanding of the described embodiments for the purpose of explanation. However, it will be apparent to those skilled in the art that, after reading this specification, the specific details are not required to practice the described embodiments. Therefore, the foregoing description of specific embodiments described herein is presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to those skilled in the art that, after reading this specification and in light of the teachings above, many modifications and variations are possible.

Claims

1. An optical measurement system, comprising: A light source unit capable of generating light of any wavelength among multiple wavelengths; A multi-level optical switch network, which is optically connected to the light source unit and includes multiple output terminals; Multiple transmitter groups, each of the multiple transmitter groups being optically connected to a corresponding output terminal of the multiple output terminals; Multiple detector groups; and A controller configured to perform spectral measurements of a sample, the spectral measurements including a measurement sequence using the light source unit, the multi-level optical switch network, the plurality of emission groups, and the plurality of detector groups; as well as Analyzing the spectroscopic measurements to determine one or more properties of the sample, wherein the measurement sequence includes: The plurality of wavelengths are divided into a plurality of groups, wherein each of the plurality of groups is associated with a different corresponding output configuration, and the different corresponding output configurations have a different number of emission groups that will simultaneously receive light; as well as A set of measurements is performed for each of the plurality of wavelengths with a corresponding output configuration for that wavelength, such that for each of the set of measurements for each wavelength, light is simultaneously emitted from a corresponding number of the plurality of emission groups.

2. The optical measurement system according to claim 1, wherein: The plurality of groups includes a first group associated with a first output configuration and a second group associated with a second output configuration; and Performing the set of measurements for each of the plurality of wavelengths includes: Perform a first set of measurements for a first wavelength in the first set, each measurement in the first set including: The light source unit is used to generate light of the first wavelength; Light generated from a set of emission groups selected from the plurality of emission groups and having a first number of emission groups corresponding to the first output configuration; and The return light received during the emission of the generated light is measured using a set of detector group correspondences selected from the plurality of detector groups and having the first number of detector groups; and Perform a second set of measurements for the second wavelength in the second set, each measurement in the second set including: The light source unit is used to generate light of the second wavelength; Light generated is emitted from a set of emission groups selected from the plurality of emission groups and having a second number of emission groups corresponding to the second output configuration; and The return light received during the emission of the generated light is measured using a set of detector group correspondences selected from the plurality of detector groups and having the second number of detector groups.

3. The optical measurement system according to claim 2, wherein: The first set of measurements includes multiple measurements with different sets of emission group correspondences and different sets of detector group correspondences.

4. The optical measurement system according to claim 2, wherein: Each measurement in the first set of measurements also includes: The multi-level optical switch network is configured to route the light of the first wavelength to the set corresponding to the emission group.

5. The optical measurement system according to claim 4, wherein: Each measurement in the first set of measurements also includes: The background light received before the emission of the generated light is measured using the corresponding set of detectors; and In each of the first set of measurements, the multi-level optical switch network is configured to be performed at least partially simultaneously with the measurement of the background light.

6. An optical measurement system, comprising: A light source unit capable of generating light of any wavelength among multiple wavelengths; A multi-level optical switch network, optically connected to the light source unit; and Multiple launch groups; and The controller is configured to: Spectral measurements of the sample are performed using the aforementioned multiple wavelengths; as well as The spectral measurements are analyzed to determine one or more properties of the sample, wherein: The multi-level optical switch network includes multiple output terminals, each of which is optically connected to a corresponding transmission group in the multiple transmission groups. The multi-level optical switch network can be controlled to selectively route the light generated by the light source unit to the plurality of emission groups with different output configurations, the different output configurations having different numbers of emission groups that will simultaneously receive light; Each of the plurality of wavelengths is associated with a different corresponding output configuration; and The controller is also configured to perform a set of measurements for each of the plurality of wavelengths with a corresponding output configuration for that wavelength, such that for each of the set of measurements for each wavelength, light is simultaneously emitted from a corresponding number of the plurality of emission groups.

7. The optical measurement system according to claim 6 further includes a photonic integrated circuit, wherein: The photonic integrated circuit includes the light source unit, the multi-level optical switch network, and the plurality of emission groups.

8. The optical measurement system of claim 7, wherein each emission group includes a corresponding output coupler configured to emit light from the photonic integrated circuit.

9. The optical measurement system according to claim 7, further comprising: Multiple detector groups.

10. The optical measurement system according to claim 9, further comprising: Intermediate layer, wherein: The photonic integrated circuit and the plurality of detector groups are mounted on the interposer layer.

11. The optical measurement system according to claim 6 further includes a first wavelength locking unit.

12. The optical measurement system according to claim 11, wherein: The multi-level optical switch network includes a first level and a second level, wherein the first level includes a first controllable switch; The first controllable switch includes a first tap; and The first wavelength locking unit is optically connected to the multi-stage optical switch network via the first tap.

13. The optical measurement system according to claim 12, further comprising: The second wavelength locking unit, wherein: The first stage includes a second controllable switch; The second controllable switch includes a second tap; and The second wavelength locking unit is optically connected to the multi-stage optical switch network via the second tap.

14. The optical measurement system according to claim 12, wherein: The first controllable switch includes an additional tap; The first tap extracts light from the first pin of the first controllable switch; and The additional tap extracts light from the second pin of the first controllable switch.

15. A method for characterizing a sample, comprising: Select multiple wavelengths; Spectral measurements of the sample are performed using the multiple wavelengths; as well as The spectral measurements are analyzed to determine one or more properties of the sample, wherein: Performing the spectral measurements includes executing a measurement sequence to generate multiple sets of output signals, the measurement sequence including: The plurality of wavelengths are divided into a plurality of groups, wherein each of the plurality of groups is associated with a different corresponding output configuration, and the different corresponding output configurations have a different number of emission groups that will simultaneously receive light; A set of measurements of the sample is performed for each of the plurality of wavelengths with a corresponding output configuration for that wavelength, such that for each measurement in the set of measurements for each wavelength, light is simultaneously emitted from a corresponding number of the plurality of emission groups; and For each set of measurements, a corresponding set of output signals is generated from the plurality of output signals; and The multiple sets of output signals are used to determine one or more properties of the sample.

16. The method of claim 15, wherein: The plurality of groups includes a first group associated with a first output configuration and a second group associated with a second output configuration; and Performing the set of measurements on the sample for each of the plurality of wavelengths includes: Perform a first set of measurements on the sample for a first wavelength in the first set, each measurement in the first set including: Generate light of the first wavelength; Light generated from a set of emission groups selected from the plurality of emission groups and having a first number of emission groups corresponding to the first output configuration; and The return light received during the emission of the generated light is measured using a set of detector group correspondences selected from multiple detector groups and having the first number of detector groups; and Perform a second set of measurements on the sample for the second wavelength in the second set, each measurement in the second set including: Generate light of the second wavelength; Light generated is emitted from a set of emission groups selected from the plurality of emission groups and having a second number of emission groups corresponding to the second output configuration; and The return light received during the emission of the generated light is measured using a set of detector group correspondences selected from the plurality of detector groups and having the second number of detector groups.

17. The method of claim 16, wherein: The first set of measurements includes multiple measurements with different sets of emission group correspondences and different sets of detector group correspondences.

18. The method of claim 16, wherein: Each measurement in the first set of measurements also includes: The multi-level optical switch network is configured to route the light generated at the first wavelength to the corresponding set of the emission groups.

19. The method of claim 18, wherein: Each measurement in the first set of measurements also includes: The background light received before the emission of the generated light is measured using the corresponding set of detectors; and In each of the first set of measurements, the multi-level optical switch network is configured to be performed at least partially simultaneously with the measurement of the background light.

20. The method of claim 15, wherein the measurement sequence is divided into a plurality of subsequences, wherein: Each subsequence has a corresponding group of wavelengths from the plurality of wavelengths and a set of corresponding emission groups selected from the plurality of emission groups, and Each subsequence includes a measurement of the sample for each wavelength in the corresponding group of wavelengths, during which light of that wavelength is emitted from the corresponding set of emission groups.

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