Photonic integrated circuit, system, and method for high-speed scanning laser ophthalmoscopy

Abstract

According to an aspect of the present inventive concept there is provided a photonic integrated circuit, PIC, (100) for scanning laser ophthalmoscopy, SLO, the PIC (100) comprising: a splitter (110), and a plurality of waveguide paths (120), wherein the splitter (110) is configured to receive a light signal (102), and split the light signal (102) into the plurality of waveguide paths (120), wherein each waveguide path (120) comprises: an interface component (122) configured to output a light beam (122o) and receive a response signal (122r) based on the outputted light beam (122o), and a photo detection module (124) configured to receive the response signal (122r) from the interface component (122), the photo detection module (124) comprising a photodetector (125) configured to detect the response signal (122r), wherein the interface components (122) of the waveguide paths (120) are configured to output the light beams (122o) in parallel to each other.

Description

[0001] PHOTONIC INTEGRATED CIRCUIT, SYSTEM, AND METHOD FOR HIGHSPEED SCANNING LASER OPHTHALMOSCOPY

[0002] Technical field

[0003] The present description relates to the field of ophthalmic imaging, specifically to an improved photonic integrated circuit, system, and method for Scanning Laser Ophthalmoscopy.

[0004] Background

[0005] Scanning Laser Ophthalmoscopy (SLO) is an advanced imaging technology used in ophthalmology to produce high-resolution reflectance and fluorescence images of the retina. This technique employs scanning laser beams of various colors to generate detailed retinal images, which are used for diagnosing and monitoring retinal diseases.

[0006] In the prior art, SLO systems typically utilize bulk optics where output beams from different light sources, such as lasers or super luminescent diodes, are combined into a single beam. This combined beam is directed towards the retina through an X- and Y-directional scanning mirror and a series of imaging optics. The imaging optics, in conjunction with the lens of the eye, focus the beam into a single illumination spot on the retina.

[0007] The illumination spot is raster scanned across the retina using the X-Y scanning mirrors. The scanning process then involves moving the beam from one side to the other (e.g., left to right, X-scan direction) and then shifting to a next line in a top-to-bottom progression (Y-scan direction). Such methods create a reflectance or fluorescence image. The reflected light is then separated by dichroic mirrors, which distinguish the light based on the different wavelengths of the illumination sources.

[0008] Raster scanning provides high-resolution, detailed images and comprehensive coverage of the retina. However, the process is slow, especially for high-density scans, and often requires steady patient cooperation to keep the eye still to avoid motion artifacts.

[0009] Hence, there is a need for an improved and faster Scanning Laser Ophthalmoscopy system that can provide high-resolution images with reduced scanning time and minimized motion artifacts. Summary

[0010] An objective of the present description is to enable high imaging speed of Scanning Laser Ophthalmoscopy (SLO) systems.

[0011] Another objective is to enable a low risk of motion artifacts in imaging and enable reliable imaging results to be acquired despite involuntary eye movements.

[0012] A further objective is to provide versatility of a photo integrated circuit (PIC), making it adaptable to various and multiple wavelengths.

[0013] These and other objectives are at least partly met by the invention as defined in the independent claims. Preferred embodiments are set out in the dependent claims.

[0014] According to an aspect, there is provided a photonic integrated circuit, PIC, for scanning laser ophthalmoscopy, SLO. The PIC comprises: a splitter, and a plurality of waveguide paths, wherein the splitter is configured to receive a light signal, and split the light signal into the plurality of waveguide paths, wherein each waveguide path comprises: an interface component configured to output a light beam and receive a response signal based on the outputted light beam, and a photo detection module configured to receive the response signal from the interface component, the photo detection module comprising a photodetector configured to detect the response signal, wherein the interface components of the waveguide paths are configured to output the light beams in parallel to each other.

[0015] In other words, multiple output light beams are provided in parallel such that the a plurality of light beams can be outputted via the waveguide paths simultaneously in a first direction.

[0016] In yet other words, the PIC can generate multiple beams and simultaneously detect reflections from each beam.

[0017] Hereby, there is provided an improved PIC for SLO, enabling faster acquisition of high-resolution images. In particular, the issue of motion artifacts caused by involuntary eye movements is addressed by the achieved increase of scanning speed. Hence, improved image quality may be achieved. In addition, a satisfactory image quality may be achieved in one attempt or possibly a few attempts of performing SLO on a patient, such that a low number of attempts are needed to obtain a clear scan.

[0018] The term ‘waveguide paths’ may here refer to the channels within the PIC that guide light signals. The waveguide path may include a waveguide. The waveguide may be any structure providing guiding of a light signal. The waveguide may be configured to confine light in a cross-section perpendicular to an extension of the waveguide. The waveguide may thus be configured restrict light to follow a path defined by the extension of the waveguide, whereby transmission of light with low loss may be provided. The waveguide may for instance guide light by light being reflected on inner walls of the waveguide by total internal reflection or by a reflective coating being provided on the walls of the waveguide. The waveguide is configured to propagate the light signal along the waveguide. The waveguide may extend from the splitter to the interface component for guiding light therebetween.

[0019] The interface component may be configured to output light from the PIC into free space. Thus, the interface component may form an interface between the PIC and a free space propagation of the light signal. The interface component is configured to control direction of the light signal and the response signal. Thus, the interface component enables output of light beam for SLO received from the splitter and capturing of the response signal.

[0020] The interface component may be configured to guide the light signal from the waveguide to output the light beam. The interface component may further be configured to guide the received response signal to the photo detection module for detecting the response signal.

[0021] Thanks to the use of the interface components, light beams may be output and response signals may be received in a common location. This implies that the PIC for SLO may be very compact.

[0022] The PIC is configured to provide output of a plurality of light beams and provide detection of response signals in a single integrated component. This enables a compact SLO system to be provided, avoiding or reducing a need for bulky components. For instance, thanks to the output of the plurality of light beams, the SLO system may only need limited scanning of the outputted light beams for forming an image of a retina.

[0023] It should be realized that the term “scanning laser ophthalmoscopy (SLO)" may often be associated with scanning in two dimensions. However, as mentioned above, thanks to the output of the plurality of light beams, the SLO system may only need limited scanning. Thus, the term SLO should not be construed as necessarily involving scanning in two directions. Rather, scanning may in some embodiments be performed only in a single direction. It should further be realized that in other embodiments, scanning in two directions may still be used.

[0024] The photo detection module may comprise any type of photodetector for detecting incident light. Thus, the photo detection module may be configured to generate a signal, such as an electrical signal, in response to the incident light, wherein an amplitude of the signal from the photo detection module may be dependent on intensity of the incident light. Given as nonlimiting examples, the photo detection module may comprise a photodiode, a phototransistor, or a photomultiplier tube for detecting the response signal.

[0025] The light signal received by the splitter may be generated by a light source. The light source may be integrated within the PIC or positioned externally from the PIC (i.e. , the light source may be an external light source). When integrated within the PIC, the light source may be designed to be compact. The light source generating the light signal may, e.g., be a laser. However, it is further appreciated that other types of light sources may be employed.

[0026] The splitter may be a 1xN splitter and / or a splitter tree. For example, the splitter may be 1x16 splitter such that the light signal received by the splitter is split into 16 different parts.

[0027] The interface components may, e.g., be 2x2 splitters, polarization beam splitters, and / or optical circulators.

[0028] Further, the plurality of response signals received by the plurality of waveguide paths may be reflected signals or fluorescence signals. In other words, the outputted parallel light beams may be configured to be reflected back to the PIC, e.g. via the retina or cause fluorescence, e.g., in the retina, for forming the fluorescence signal. There may, e.g., be imaging optics between the PIC and a target (e.g., an eye) for forming an image of the response signals. The imaging optics may both focus light towards the target and capture signals from the target for providing imaging by confocal microscopy.

[0029] The outputted parallel light beams may correspond to a same color or wavelength, i.e., the PIC may be configured to output a single color. However, the outputted parallel light beams may each correspond to wider color wavelength bands, i.e., the parallel light beams may each cover a wider spectrum of wavelengths.

[0030] Alternatively, or additionally, a repeating wavelength pattern or color pattern (e.g., red, green, blue) may be employed. In other words, the parallel light beams may incorporate a repeating sequence of colors repeated throughout the (array of) outputted parallel light beams, e.g., in order, a first of the outputted light beams may be red, a second may be green, a third may be blue, a fourth may be red, a fifth may be green, a sixth may be blue, etc.

[0031] In an example, the outputted light beams may form a stack of light beams. The stacked light beams may be arranged orthogonally to a distribution of the parallel beams. In other words, a two-dimensional grid or square pattern of light beams may be provided. The PIC may hence comprise stacked layers of waveguides and / or interface components. Hence, multiple colors or wavelengths may be output in a stacked manner by one PIC.

[0032] According to one embodiment, the PIC may further comprise a modulator. The modulator may amplitude-modulate the light signal.

[0033] The amplitude-modulated light signal may be used for preventing interference from ambient light and / or other sources. The modulator may provide a modulation frequency to the light signal. Light modulated at the modulation frequency may be detected in the detected response signal allowing other frequencies to be filtered out. Hence, the detected response signal may be processed to increase a signal-to-noise ratio.

[0034] The modulator being part of the PIC may reduce the cost and complexity of an overall SLO system. However, it is appreciated that the modulator may alternatively be located externally to the PIC.

[0035] The modulator may be a device such as an electro-optic modulator or an acousto-optic modulator, which may physically alter properties of the light signal.

[0036] The modulator may be arranged such that the light signal is passed through the modulator before reaching the splitter. Thus, the light signal in each waveguide path may have a common amplitude-modulation.

[0037] However, according to an alternative, each waveguide path may comprise a modulator. This implies that the light signal in each of the plurality of waveguide paths may be amplitude-modulated with a unique frequency. This may be useful for differentiating between the light signals and to avoid or reduce the effect of crosstalk between different channels. However, having a separate modulator in each waveguide path implies that complexity of the PIC is substantially increased.

[0038] In an example, the PIC may further comprise an optical amplifier, e.g., after the modulator (in a direction of the light signal). The optical amplifier may be arranged such that the light signal is passed through the optical amplifier before reaching the splitter. According to an alternative, each waveguide path may comprise an optical amplifier for amplifying the light signal in the waveguide path. Thereby, the light signal may be amplified, e.g., in case where a power of a laser generating the light signal is not sufficiently high for being suitable for SLO, or the power of the laser is not sufficiently high for supporting a sufficient power in each of the plurality of waveguide paths.

[0039] According to one embodiment, the PIC may further comprise an entry waveguide for guiding the light signal to the splitter, wherein the entry waveguide may comprise an entry splitter configured to divert a portion of the light signal to an entry photodetector configured to monitor a power level of the light signal and / or compensate for intensity variations in the light signal.

[0040] In other words, the entry waveguide may be configured to lead the light signal from an external or internal light source of the PIC to the splitter. If the light source is part of the PIC, the entry waveguide may consequently receive the light signal internally on the PIC.

[0041] By monitoring the power level of the light signal and / or compensating for intensity variations in the light signal, dynamical adjustments may be enabled to maintain stable and efficient operation.

[0042] The modulator may be configured to modulate the light signal propagating in the entry waveguide.

[0043] According to one embodiment, each interface component may comprise an absorber, wherein each absorber may be configured to absorb residual light and optionally act as a monitoring photodetector for monitoring a power level of the outputted light beam.

[0044] The absorber may be arranged such that the light signal propagating in a waveguide towards the interface component may be partially provided to the absorber and partially output to form the light beam. The interface component may thus comprise a 2x2 splitter, which may provide a simple implementation for controlling the direction of the light in the interface component.

[0045] In other words, the absorbers may always absorb residual light (i.e., discard unused light). The interface component may be configured such that a small fraction of the light signal in the waveguide path is provided to the absorber to ensure that a small fraction of light is lost in the interface component.

[0046] However, the absorbers may further, in certain embodiments (e.g., when the absorbers are processed as photodetectors by doping and metallization) additionally provide a photodetection function for monitoring the outputted light beams. Hence, the absorbed light at each absorber may, e.g., be converted to current and used to, respectively, monitor the power level of each outgoing light signal beam.

[0047] According to one embodiment, each photo detection module may further comprise a filter configured to filter the response signal, wherein the filter may be configured to pass only a specific wavelength of light to the photodetector, and / or block excitation light from being received by the photodetector. In other words, filter may selectively allow only certain wavelengths of light to reach the photodetector, and the filter may block unwanted excitation light, preventing it from interfering with the detection of the response signal by the photodetector. The filter may, e.g., be configured to block excitation light such that only a fluorescence signal is passed.

[0048] Hence, the photodetector can detect specific types of light more accurately, without being affected by light from other light sources. By allowing only specific wavelengths of light to pass through, the filter ensures that the photodetector receives only the desired signals, reducing noise and potential errors.

[0049] The filtered signal may further be configured to be converted into an electrical signal by the photodetector.

[0050] According to one embodiment, the interface components may be 2-by- 2 splitters, polarization beam splitters, and / or optical circulators.

[0051] A 2-by-2 splitter may divide an optical signal into two separate paths, a polarization beam splitter may separate light based on its polarization state, directing different polarizations into different paths, and an optical circulator may direct light from one port to another in a unidirectional manner. Alternatively, the interface components may be 2-by-1 splitters.

[0052] Light exiting the PIC may pass through the interface components (i.e. splitters or optical circulators) such that part of the light exits the PIC, while another part is absorbed (e.g., in the absorber). If the light is reflected back from the retina, it may be recaptured by the same interface component and corresponding waveguide that initially transmitted it. Upon returning to the spitter or optical circulator, a portion of the reflected light may continue through the waveguide of the waveguide path, while another portion of the light is directed towards the photo detection module.

[0053] Hence, flexible signal routing may be provided. Polarization beam splitters may improve management of polarized light, while optical circulators may enable efficient light direction control. Additionally, the ability to recapture and redirect reflected light may facilitate reliable measurements.

[0054] In another configuration, an additional interface component may be added to divert fluorescence wavelengths to a filter that passes fluorescent light to a separate photodetector. Hence, simultaneous detection of both fluorescence and reflection may be enabled.

[0055] In an embodiment where polarization beam splitters may be utilized as the interface components, light may be separated into two orthogonally polarized components, directing each polarization into a different path. When light generated by a light source in a transverse electric (TE) mode exits the PIC, most of the light may pass straight through the polarization beam splitter to a through port (i.e. for outputting a light beam and / or receiving a response signal), while only a transverse magnetic (TM) mode light is diverted to a cross port (i.e. for guiding light to an absorber).

[0056] In practice, a small portion of the TE-mode light may also be directed to the cross port due to imperfections in the splitter. This residual light may be absorbed by an absorber to prevent interference. When light is reflected back from the retina, some of the TE-mode (illuminating) light may undergo polarization rotation, resulting in the reflected light containing both TE and TM polarized components. The TE polarized light may continue from the through port to the waveguide, while the TM polarized light may be directed towards the filter and the photodetector.

[0057] Additionally, a quarter-wave plate may convert the reflected TE light into TM light. This may ensure that the reflected light can be efficiently detected, minimizing any loss of reflected light in the splitter.

[0058] According to one embodiment, the PIC may comprise 2 to 2048 waveguide paths. In other words, the PIC may include a variable number of waveguide paths. It is appreciated that any suitable number of waveguides may be used.

[0059] Hence, the PIC may be a scalable PIC.

[0060] The number of waveguides may, e.g., be related to the 1xN splitter or splitter tree, where N waveguides may connect to the 1xN splitter for guiding light signals to the interface components. The PIC may hence comprise N interface components for outputting N light beams, e.g., in parallel towards a retina.

[0061] In configurations with a limited or low number of waveguides, the PIC may be less complex, however, a more extensive scanning requiring a longer scanning time may be required to scan the entire target. Conversely, configurations with a greater number of waveguides may lead to increased PIC complexity, however, faster scanning may be enabled, thereby expediting the SLO.

[0062] According to another aspect, there is provided a scanning laser ophthalmoscopy, SLO, system. The SLO system comprises: a splitter, and a plurality of waveguide paths, wherein the splitter is configured to receive a light signal, and split the light signal into the plurality of waveguide paths, wherein each waveguide path comprises: an interface component configured to output a light beam and receive a response signal based on the outputted light beam, and a photo detection module configured to receive the response signal from the interface component, the photo detection module comprising a photodetector configured to detect the response signal, wherein the interface components of the waveguide paths are configured to output the light beams in parallel to each other.

[0063] In other words, there may be provided an SLO system comprising a PIC according to the former aspect. In yet other words, a PIC of the SLO system may be configured to receive a light signal, output a plurality of parallel light beams, and receive a plurality of response signals based on the outputted plurality of parallel light beams.

[0064] This aspect may generally present the same or corresponding advantages as the former aspect.

[0065] According to one embodiment, the SLO system may further comprise a scanning mirror, and imaging optics. In other words, a PIC according to the former aspect may be integrated in a system together with a scanning mirror and imaging optics.

[0066] The imaging optics may be lenses and / or other optical elements that focus and direct the outputted and reflected light beams.

[0067] The scanning mirror may be a device that is movable for directing the outputted light beams across the imaged area. Since the light beams are configured to be outputted in parallel to each other, the outputted light beams may be scanned across the imaged area in a parallel manner. The parallel scanning enables efficient imaging since the outputted light beams simultaneously cover different vertical (or horizontal) positions on the imaged area, e.g. in a single step of a scanning procedure.

[0068] Hence, the scanning mirror may be a single scanning mirror configured to provide a scanning movement in a single dimension, e.g., if the distribution of the outputted parallel light beams span the entire vertical range of the area being imaged. However, if the distance between the outputted light beams is not sufficiently small to obtain a desired resolution, two scanning mirrors or a multi-axis mirror (e.g., a gimbal mirror, a galvanometric, resonant or MEMS X- Y mirror pair) may be used.

[0069] The scanning mirror be an on-chip deflector. Hence, an on-chip beam steering device, such as an optical phase array, may be provided. Thus, a more compact design may be provided. Further, controlling and steering of light beams may be achieved within a smaller footprint.

[0070] According to one embodiment, the scanning mirror and the imaging optics may be configured to direct the outputted plurality of parallel light beams to a retina, and to direct the plurality of response signals from the retina to the interface components (e.g. of a PIC) of the SLO system.

[0071] Hence, the imaged area may be a retina. The outputted parallel light beams may be configured to span a major range or area of the retina. While scanning the parallel light beams over the retina, the reflected light from each beam may be collected by the same waveguide and interface component that output the light beam.

[0072] The parallel light beams may, e.g., span or cover a 2 cm line in the retina. In such a case, 1000 parallel light beams may provide a 20 pm resolution of the retina.

[0073] According to one embodiment, the SLO system may comprise a plurality of PICs according to the former aspect. Each PIC may be configured to handle a specific wavelength range, or a combination of specific wavelength ranges, such as a wavelength corresponding to red, blue, green, and / or near-infrared.

[0074] For example, one PIC may be dedicated to red light (e.g., wavelengths from about 620 to 750 nm), while another might handle blue light (e.g., ranging from 450 to 495 nm). Similarly, green light (with wavelengths from, e.g., 495 to 570 nm) and near-infrared light (e.g., ranging from 750 to 1400 nm) may each have a dedicated PIC.

[0075] For example, when PICs configured for red, green, and blue wavelengths are utilized in conjunction, a color image may be produced. By combining the readings form the reflected response signals, the system can generate a spectrum of colors by mixing the different wavelengths in varying intensities to achieve desired colors. Consequently, the system may utilize different wavelengths to form color images. Further, the different wavelengths may be used for producing spectral images.

[0076] Phrased differently, to image a retina using light beam arrays with these multiple colors, when combined with the scanning mirror and imaging optics, enables fast color scanning of the retina. The different colored light beams may, e.g., trail each other during the scanning process, meaning that the red light is scanned in a line, followed closely by the green light, and subsequently by the blue light. The resulting scanning pattern may allow for the simultaneous capture of images in different wavelengths, hence producing a color image of the retina. Particularly, the sequential, yet simultaneous, scanning may ensure that each color is slightly offset from the previous one, allowing for precise color alignment and accurate image reproduction.

[0077] The PICs may be stacked PICs, e.g., forming two or more layers of parallel light beams. Alternatively, two or more layers of parallel light beams may be formed by a single PIC comprising two or more waveguide layers in one integrated unit, i.e. a multi-layered photonic circuit. Alternatively, the PICs may be arranged separately in the SLO system.

[0078] Stacked PICs may be fabricated using a simpler process compared to multi-layered PICs. Multi-layered PICs may involve more complex fabrication steps, however, they offer the advantage of having output beams positioned closer to each other. Thus, improved coverage of a larger imaging area with multiple colors is enabled, e.g., facilitating high-resolution and multiwavelength imaging.

[0079] According to one embodiment, the SLO system may be integrated with an Optical Coherence Tomography, OCT, module. The OCT module may be configured to use light to capture three-dimensional images from within biological tissues such as a retina.

[0080] In other words, the SLO system may be utilized in a system that combines it with an OCT system, creating a dual-modality SLO / OCT system. A light beam produced by the OCT system may, e.g., be integrated into the SLO system using a beam splitter.

[0081] The addition of the OCT imaging modality provides additional information about the retina and may increase diagnostic accuracy.

[0082] Further, by simultaneously acquiring OCT and SLO images, SLO images may be used to correct for motion artefacts and enable more accurate averaging in OCT imaging, e.g., since SLO imaging speed may be higher (such as 10 - 100 times higher) and produce more frames per second than OCT.

[0083] According to one embodiment, the SLO system may be integrated with a Hyperspectral Imaging, HSI, module. The HSI module may be configured to capture and process information across multiple wavelength bands.

[0084] Hyperspectral imaging refers to the imaging technique of information from across the spectrum, which may include visible light but may also include other parts of the electromagnetic spectrum, such as near-infrared light and infrared light.

[0085] Hyperspectral imaging refers to imaging of narrow spectral bands over a contiguous spectral range. Hyperspectral imaging may produce spectra for all pixels in an object to be imaged. For instance, hyperspectral imaging may refer to imaging using 8 or more wavelength bands, wherein each wavelength band may have a bandwidth of less than 50 nm, such as less than 20 nm.

[0086] Hereby, a more comprehensive analysis of the scanned area is provided. The HSI integration may enable the SLO system to further collect detailed spectral data from each point in a scanned image, such as of a retina.

[0087] Further, by capturing data across a wide range of wavelengths, the HSI module may identify and differentiate between various materials and structures based on their spectral signatures.

[0088] Moreover, HSI may contain wavelengths that are not available in SLO and thus provide additional spectral reflectance information.

[0089] According to another aspect, there is provided a method for optically scanning a retina, the method comprising: outputting a plurality of light beams in parallel to each other to the retina via a plurality of interface components, receiving, at the plurality of interface components, response signals based on the outputted plurality of light beams, and detecting the response signals at a plurality of photodetectors.

[0090] This aspect may generally present the same or corresponding advantages as the former aspects.

[0091] The method may be performed by a PIC or an SLO system according to the former aspects.

[0092] The method may comprise, on a PIC, receiving, a light signal, and splitting, in a splitter, the light signal into a plurality of waveguide paths. The method may further comprise a plurality of waveguides connected, respectively, to the plurality of interface component such that each waveguide path may output a light beam to the retina via the interface components.

[0093] Further, the method may comprise directing the parallel light beams to the retina via a scanning mirror and imaging optics. The plurality of response signals may further be directed from the retina to the interface components via the imaging optics and the scanning mirror.

[0094] According to one embodiment, the method may further comprise scanning the retina with a plurality different wavelengths, such as wavelengths corresponding to red, blue, green, and / or near-infrared.

[0095] The retina may be scanned with light of different wavelengths in a simultaneous manner. In other words, scanning the retina with a plurality of different wavelengths may be performed in single scan of the retina (i.e. one sweep of the outputted parallel light beams over the retina).

[0096] The method may, e.g., comprise employing a plurality of PICs, each PIC handling a specific wavelength, such as a wavelength corresponding to red, blue, green, or near-infrared.

[0097] Hereby, more detailed analysis of retinal structures may be provided. By using multiple wavelengths, the method may, in addition to creating color images of the retina, capture a wider range of information, as the different wavelengths may penetrate the retinal tissue to varying depths and interact differently with different components of the retina.

[0098] For instance, red light (620 to 750 nm) may provide information about deeper retinal layers, while blue light (450 to 495 nm) may be more effective for imaging the superficial layers. Green light (495 to 570 nm) may offer a balance, providing clear images of the intermediate layers. Near-infrared light (750 to 1400 nm) can penetrate deeper into the retina, offering insights into the choroid and other underlying structures. By combining data from the different wavelengths, the method may provide detailed images of the retina.

[0099] Brief description of the drawings

[0100] The above, as well as additional objects, features and advantages of the present inventive concept, will be better understood through the following illustrative and non-limiting detailed description, with reference to the appended drawings. In the drawings like reference numerals will be used for like elements unless stated otherwise.

[0101] Fig. 1 A is a schematic illustration of a photonic integrated circuit, PIC. Fig. 1 B is a schematic illustration of a splitter.

[0102] Fig. 1 C is a schematic illustration of an interface component comprising an absorber, and a photo detection module comprising a photodetector and a filter.

[0103] Fig. 2A is a schematic illustration of a PIC according to Fig. 1 A comprising a modulator and an optional amplifier.

[0104] Fig. 2B is a schematic illustration of a PIC according to Fig. 1 A or Fig. 2A, comprising an optional modulator, an optional amplifier, an entry splitter, and an entry photodetector.

[0105] Fig. 3A is a schematic illustration of a scanning laser ophthalmology, SLO, system for scanning a retina.

[0106] Fig. 3B is a schematic illustration of an SLO system according to Fig. 3A further comprising a fixation target.

[0107] Fig. 4 is a schematic illustration of an SLO system being integrated with an optical coherence tomography module, OCT.

[0108] Fig. 5 is a schematic illustration of an SLO system being integrated with a hyperspectral imaging, HSI, module.

[0109] Fig. 6A is a schematic illustration of outputted parallel light beams from a PIC or SLO system.

[0110] Fig. 6B is a schematic illustration of stacked outputted parallel light beams from a multi layered PIC, three separate PICs, or an SLO system.

[0111] Fig. 6C is a schematic illustration of outputted parallel light beams with a repeating sequence of different wavelengths in the parallel light beams.

[0112] Fig. 7 shows a diagram of a method for optically scanning a retina.

[0113] Detailed description

[0114] Fig. 1A illustrates a photonic integrated circuit, PIC, 100 for scanning laser ophthalmoscopy, SLO. The PIC 100 comprises a splitter 110, and a plurality of waveguide paths 120 (specifically N waveguide paths 120, where N may, e.g., be in the range of 2 to 2048).

[0115] The splitter 110 receives a light signal 102 and splits the light signal 102 into the plurality of waveguide paths 120. Further, each waveguide path 120 comprises an interface component 122 outputting a light beam 122o and receiving a response signal 122r. Each waveguide path 120 may comprise a waveguide 121 extending from the splitter 110 to the interface component 122 for transporting the light signal in the waveguide path 120 to the interface component 122. Although not shown in Fig. 1A, the response signal 122r received by each interface component 122 is based on (i.e., a result of) the outputted light beam 122o of each interface component 122.

[0116] Although not shown, the light signal 102 may be generated by a light source arranged externally to the PIC 100 or on the PIC 100.

[0117] In Fig. 1A, each waveguide path 120 further comprises a photo detection module 124 configured to receive the response signal 122r after having been received by the corresponding interface component 122. Hence, for detecting the response signal 122r in each photo detection module 124, each photo detection module 124 comprises a photodetector 125.

[0118] As illustrated by the arrangement of the waveguides 121 and interface components 122 in Fig. 1A, the interface components 122 of the waveguide paths 120 are configured to output the light beams 122o in parallel to each other. The parallel output of the light beams 122o will be further discussed in relation to Figs. 6A-B.

[0119] In other words, the waveguide paths 120 output an array of N light beams 122o, with each waveguide path 120 in the array configured to direct its respective light beam out from the PIC 100. The waveguide paths 120 may, e.g., include edge couplers, designed to expand the output optical mode of each light beam 122o. The expansion may serve to reduce the numerical aperture of the outputted light beams 122o, thereby improving the beam quality and reducing beam divergence. As illustrated in Figure 6A, a front view of the array of parallel light beams 122o is provided, showing the alignment of the outputted light beams 122o as they exit the waveguide paths 120.

[0120] Fig. 1 B illustrates an exemplary (optical) splitter 110 or splitter tree. The splitter 110 splits the incoming light signal 102 into a plurality of light signals. In the depicted embodiment, the splitter 110 is configured as a 1x16 splitter. This may be achieved by the single input light signal 102 being sequentially split in multiple 1x2 splitters into a total of 16 distinct light signals. Alternatively, a single input light signal may be directly split into 16 distinct light signals in a single splitter or in fewer sequential steps, e.g., using multiple 1x4 splitters. However, the splitter 110 may divide the light signal 102 into any suitable N number of light signals. For example, the splitter 110 may be configured as a 1x2, 1x4, 1x8, 1x2048, or higher-order splitter depending on a desired splitting ratio.

[0121] The splitter 110 divides incoming light signal 102 into multiple signals using passive optical components, which do not require external power or active components. The splitter 110 may distribute the light signal 102 uniformly for providing a balanced output to the plurality of waveguides.

[0122] In the case of a 1x16 splitter, the input light signal 102 is split into 16 equal portions, with each output carrying a fraction (1 / 16th) of the optical power from the input light signal 102.

[0123] In some configurations, the splitter 110 may be designed to split light signals based on wavelength. For example, the splitter 110 may split the light signal 102 into distinct wavelength bands.

[0124] Fig. 1 C illustrates an interface component 122 and a photo detection module 124. The interface component 122 comprises an absorber 123 configured to absorb residual light and optionally act as a monitoring photodetector for monitoring a power level of the outputted light beam 122o. The absorber 123 may act as a photodetector by employing doping and metallization techniques for allowing it to convert the absorbed light into an electrical current. In other words, the power level of the outgoing light beams 122o may be monitored, e.g., such that an optical power of each light beam 122o may be consistent or calibrated based on the detected power levels.

[0125] The interface component 122 may be utilized for the routing, splitting, and processing the outputted light beams 122o and incoming response signals 122r.

[0126] The interface component 122 in Fig. 1 C comprises a splitter 127. The splitter 127 of the interface component 122 may, e.g., be a 1x2 splitter, a 2x2 splitter (as illustrated in Fig. 1 C), a polarization beam splitter (PBS), and / or an optical circulator.

[0127] As a 1x2 splitter, the interface component 122 may take the incoming optical signal and divide it into one output light beam 122o and one signal for processing or control measurements. The splitting ratio may vary to optimize the signal to noise ratio depending on the power of the input light source, however, a half portion may represent the outputted light beam 122o, e.g., 50%. However, in an example, if 99% is outputted, on the way back 99% will continue through the same waveguide and 1% will go to the photodetector. Alternatively, 20% may be outputted and 80% may be absorbed. Then, if a power of the response signal 122r is sufficient, 80% of the reflected light may be coupled to the photodetector.

[0128] On the other hand, as a polarization beam splitter, the interface component 122 may separate an incoming response signal 122r based on its polarization state. The polarization beam splitter may have two input and two output ports, where light with one polarization (e.g., vertical) is transmitted through one output port, while light with the orthogonal polarization (e.g., horizontal) is guided to the second output port.

[0129] When the interface component 122 comprises an optical circulator, light signals may be routed from one port to another in a sequential manner, typically in a unidirectional loop. A typical circulator may have three ports: light entering from a Port 1 exits through a Port 2, and light entering from Port 2 exits through a Port 3, and so on. The circulator may prevent light from returning to the originating port (i.e., Port 1 in the above example).

[0130] In some embodiments, the interface components 122 may combine the functionalities of multiple devices. For instance, a polarization beam splitter may be integrated with an optical circulator to create a polarization-sensitive routing system (i.e., polarization sensitive imaging). In such a configuration, the polarization beam splitter may separate light based on polarization, and the circulator may ensure that the polarized signals are directed to the appropriate ports in a controlled, non-reciprocal manner.

[0131] Fig. 1 C further illustrates a photo detection module 124 comprising a filter 126. The filter 126 is configured to filter the response signal 122r by only passing a specific wavelength of light to the photodetector 125 and / or by blocking excitation light from being received by the photodetector 125.

[0132] Hence, the filter 126 of the photo detection module 124 ensures that only desired optical signals are received by the photodetector 125. The filter 126 may specifically be configured to process the response signal 122r by selectively allowing only a particular wavelength or wavelength band of light to pass through to the photodetector 125.

[0133] The photodetector 125 may subsequently convert the filtered light signal into an electrical signal.

[0134] As further illustrated in Fig. 1 C, the interface component 122 is connected to the photo detection module 124. The interface component 122 and photo detection module 124 are here connected by a waveguide arm which directs a portion of the received response signal 122r towards the filter 126 of the photodetection module 124. In other words, the waveguide arm may connect to the interface component 122 for receiving a major portion of the response signal 122r entering the interface component 122.

[0135] Alternatively, the photo detection module 124 may be integrated within the interface component 122. In other words, the interface component 122 may comprise the photo detection module 124. In such a configuration, the interface component 122 may handle both signal routing, filtering, and detection.

[0136] Generally, as seen in Fig. 1 C, at the interface component 122, the light signal transported by the waveguide 121 is divided into two portions: one portion which continues to propagate through the system, while the other portion is directed towards the absorber 123. The absorber 123 may discard unused light by absorbing it, preventing reflections or unwanted signals.

[0137] Upon reflection of the outputted light beams 122o from a target, such as the retina, the response signals 122r are recaptured by the same waveguide path 120 that originally transmitted the corresponding light beam 122o out, as illustrated in Fig. 1 C. As the reflected light, i.e. response signal 122r, travels back to the splitter 127 of the interface component 122, the splitter 127 once again divides the light. A portion of the reflected light continues through the waveguide 121 , while the waveguide arm directs the reflected light towards the filter 126 of the photo detection module 124 (the filter 126, e.g., only passing a wavelength or color of outputted light signal 122o that was used for imaging the target).

[0138] Although not shown, in some configurations, an additional interface component and / or photo detection module may be integrated to enable simultaneous detection of response signals 122r corresponding to both reflectance and fluorescence signals. Hence, fluorescence wavelengths may, e.g., be diverted to a separate filter tuned to pass the fluorescent light and guiding it to a separate photodetector. Thus, capture of both reflective properties and the fluorescence properties of the target material in parallel, without interference, may be enabled.

[0139] Fig. 2A illustrates a PIC 100, e.g., according to Fig. 1A, comprising a modulator 130. The light signal 102 is configured to be amplitude-modulated by the modulator 130 to prevent interference from ambient light and / or other sources. In other words, the light signal 102 can be amplitude-modulated at a specific desired frequency. Hence, this may allow only light modulated at the desired modulation frequency to be processed, while other frequencies are filtered out.

[0140] After modulation, the light signal 102 may be amplified in an (optical) amplifier 140, e.g., if a light source generating the light signal is not sufficient to reach near a maximum permissible power to illuminate the target, e.g., retina, at a desired wavelength. After the amplifier 140, the light signal 102 enters the splitter 110, etc., as described in detail in relation to Figs. 1A-B. It should also be realized that the amplifier 140 need not necessarily be used in combination with the modulator 130. Thus, the PIC 100 may comprise the optical amplifier 140 without including the modulator 130.

[0141] Fig. 2B illustrates a PIC 100, e.g., according to Fig. 1A, or 2A further comprising an entry waveguide for guiding the light signal 102 to the splitter 110. Specifically, here, the entry waveguide comprises an entry splitter 150 configured to divert a portion of the light signal 102 to an entry photodetector 152. The entry photodetector 152 is configured to monitor a power level of the light signal 102 and / or to compensate for intensity variations in the light signal 102.

[0142] Hence, the entry splitter 150 is in Fig. 2B configured to split the light signal 102 in a way that allows the majority of the light signal 102 to continue through the entry waveguide and towards the splitter 110 (optionally via a modulator 130 and / or an amplifier 140), while a smaller portion (e.g., 1 %) is directed to the entry photodetector 152.

[0143] Fig. 3A illustrates a scanning laser ophthalmoscopy, SLO, system 1000. The SLO system 1000 comprises a scanning mirror 200, imaging optics 300, and a PIC 100, e.g. according to Figs. 1A or 2A-B.

[0144] However, although not shown, it is appreciated that the SLO system 1000 may comprise the components of the PIC 100 without the PIC components being integrated or arranged on a PIC. In particular, the SLO system may comprise a splitter 110, and a plurality of waveguide paths 120, wherein the splitter 110 is configured to receive a light signal 102, and split the light signal 102 into the plurality of waveguide paths 120. Each waveguide path 120 then comprises an interface component 122 configured to output a light beam 122o and receive a response signal 122r based on the outputted light beam 122o, and a photo detection module 124 configured to receive the response signal 122r from the interface component 122, wherein the photo detection module 124 comprises a photodetector 125 configured to detect the response signal (122r). The interface components 122 of the waveguide paths 120 being configured to output the light beams 122o in parallel to each other.

[0145] In Fig. 3A, the scanning mirror 200 and the imaging optics 300 direct the outputted plurality of parallel light beams 122o (here illustrated with a single line) to a retina 400. The scanning mirror 200 and the imaging optics 300 further direct the plurality of response signals 122r from the retina 400 to PIC 100 (specifically to the interface components 122 of the PIC 100). Phrased differently, by using a combination of a scanning mirror 200 and imaging optics 300, as shown in Figure 3A, the plurality of parallel light beams 122o, generated an outputted by the PIC 100, can be focused onto the retina 400. The outputted parallel light beams 122o are then scanned across the retina 400 in a parallel manner, as further depicted in Figure 6A.

[0146] The scanning with simultaneously outputted parallel light beams 122o enables the scan to simultaneously cover different vertical or horizontal positions on the retina 400. Consequently, the single scanning mirror 200 is sufficient if the parallel light beams 122o span the entire vertical or horizontal range of the area being imaged. However, it is appreciated that two scanning mirrors may also be used (e.g. one for vertical alignment and one for horizontal alignment).

[0147] Although not shown, the SLO system 1000 may comprise a plurality of PICs 100, e.g., according to Figs. 1A or 2A-B. Each PIC 100 in the plurality of PICs 100 may be configured to handle a specific wavelength or wavelength band. For example, one PIC 100 may emit red light, another PIC 100 may emit blue light, yet another PIC 100 may emit green light, and / or a further PIC 100 may emit near-infrared light. Hence, the retina may be scanned using, e.g., four different wavelengths at the same time, see Fig. 6B.

[0148] Fig. 3B illustrates an SLO system 1000, e.g., according to Fig. 3A further comprising a fixation target 500.

[0149] The fixation target 500 may be used to help a patient maintain consistent focus during imaging of the patient's retina 400, thereby further improving the accuracy and quality of the retinal images obtained by the SLO system 1000.

[0150] The fixation target 500 may, e.g., be an LED, a small LED matrix, or an LCD display. The fixation target 500 may typically be of a crosshair shape, a dot, or a similar pattern, displayed on a screen.

[0151] The fixation target 500 is here integrated into the SLO system 1000 using further imaging optics. In Fig. 3B, a lens 504 is employed to focus the light of the fixation target 500. Additionally, a deflecting optics 502, such as a beam splitter, is used to direct light of the fixation target 500 to the retina 400 without obstructing the imaging path of the SLO system 1000 (i.e., without obstructing the light beams 122o and the response signals 122r).

[0152] Fig. 4 illustrates an exemplary SLO system, e.g., SLO system 1000 according to Fig. 3B, being integrated with an optical coherence tomography, OCT, module 600. The OCT module 600 is configured to use light to capture three- dimensional images from within biological tissues of the retina 400. In other words, the OCT module 600 may be an OCT system.

[0153] Further, OCT is a non-invasive imaging technique that employs broadband light to produce high-resolution cross-sectional images. An OCT system works by directing a beam of light onto the retina and interferometrically measuring the intensity of the reflected light. This data is then used to construct detailed images of retinal layers, allowing for the visualization of microstructural features.

[0154] An OCT system may typically include components such as: a light source, e.g., with a broadband light source such as a superluminescent diode femtosecond laser or swept source laser, which provides the necessary spectrum for depth resolution; a beam splitter that divides the light into reference and sample beams; a reference arm containing a fixed mirror that reflects light back to the detector; a sample arm that directs light to the tissue and collects the backscattered light; a detection system, often a spectrometer for broadband light source system or a balanced photodetector a swept- source laser system, that detects the spectral interference pattern from the recombined light and scanning and beam delivery mechanisms, which may utilize galvanometer scanners for 2D and 3D imaging.

[0155] In Fig. 4, the OCT module 600 is integrated into the SLO system 1000 through a deflecting optics 602, such as a beam splitter, used to direct light from the OCT module 600 to the retina 400 without obstructing the imaging path of the SLO system 1000. Further, a lens 604 that focuses the light from the OCT module 600 and a two-directional scanning mirror 606 to scan the light from the OCT module 600 across the retina 400, are used.

[0156] It is to be understood that the SLO system 1000 with the integrated OCT module 600 may be realized without the fixation target 500.

[0157] It should be further realized that the OCT module 600 may comprise parts that may be formed in a photonic integrated circuit which may possibly be integrated in the PIC 100 or in a separate PIC that may be arranged with the PIC 100 in a compact form factor.

[0158] The OCT module 600 may for instance provide waveguide(s) for guiding light from a light source in a PIC. The waveguides may be configured to provide a plurality of parallel channels for providing simultaneous imaging of multiple locations of the retina in the OCT module 600. In addition, or alternatively, the light source for the OCT module 600 may be integrated on the PIC of the OCT module 600.

[0159] Fig. 5 illustrates an SLO system 1000 integrated with a hyperspectral imaging, HSI, module 700. The HSI module 700 is here configured to capture and process information across multiple wavelength bands.

[0160] In addition to the PIC 100 and components of the SLO system 1000, e.g., described in relation to Fig 3B, the SLO system 1000 with the integrated HSI module 700 comprises a splitter 202 for directing the light beams 122o and response signals 122r to and from the PIC 100 and the retina 400, respectively. Further, an illumination source 706 for the HSI module 700, a deflecting optics 702, such as a mirror or beam splitter, and a lens 704 are provided to integrate the HSI module 700 with the SLO system 1000.

[0161] HSI is a technique that captures and processes data across the electromagnetic spectrum, collecting information from narrow wavelength bands instead of the traditional three primary colors (red, green, and blue). This enables the identification and analysis of materials based on their spectral signatures, providing detailed information about the composition and properties of observed objects.

[0162] The illumination source 706 hence provides a light output to the HSI module 700, which may be an HSI camera. The deflecting optics 702 directs light toward the HSI module 700 while allowing the SLO system 1000 to maintain its imaging functions. Additionally, the lens 704 provides focusing and high-resolution capture of spectral information across multiple wavelength bands.

[0163] An HSI system may generally include a high-resolution sensor capable of detecting a broad range of wavelengths (i.e., the HSI module 700), an illumination source 706 providing uniform lighting, and optics (i.e., such as the deflecting optics 702 and the lens 704). Furthermore, software for processing and analyzing the captured spectral data may be provided.

[0164] It is to be understood that the SLO system 1000 with the integrated HSI module 700 may be realized without the fixation target 500.

[0165] Fig. 6A illustrates a cross-section of outputted parallel light beams 122o from a PIC or SLO system as previously described herein.

[0166] The parallel light beams 122o are here seen from a perspective of a patient whose retina is being scanned, or from a front side of the PIC where the parallel light beams 122o are outputted form the PIC. It is to be understood that neither the circumference of the light beams 122o nor the distance between the light beams 122o are to scale in Fig. 6A. The light beams 122o may, e.g., each have a size of 2 - 20 pm. Further, the light beams 122o may be distanced from each other 2 - 50 pm. Having smaller beam sizes may help with scanning larger area and require additional magnification before light beams reach the retina, while larger beams require smaller numerical aperture optics.

[0167] In Fig. 6A, a scanning direction (i.e., movement of the parallel light beams 122o) is in a y-direction. In other words, the array of parallel light beams 122o may be scanned in a direction orthogonal to spread of the array.

[0168] Further, in Fig. 6A, the parallel light beams 122o comprises a first wavelength 160.

[0169] Fig. 6B illustrates a cross-section of stacked parallel light beams 122o outputted from one or more PICs or an SLO system as previously described herein.

[0170] Here, each layer of parallel light beams 122o comprises different wavelengths. In particular, the top layer comprises a first wavelength 160, the middle layer comprises a second wavelength 162, and the bottom layer comprises a third wavelength 164.

[0171] The first wavelength 160 may, e.g., correspond to red light (e.g., 620 to 750 nm), the second wavelength 162 may correspond to blue light (e.g., 450 to 495 nm), and / or the third wavelength may correspond to green light (e.g., 495 to 570 nm). Although not shown, at least a fourth layer of parallel light beams 122o may form part of the stacked parallel light beams 122o, such a fourth layer of parallel light beams 122o may, e.g., comprise near-infrared light (e.g., 750 to 1400 nm).

[0172] The stacked parallel light beams 122o are configured to be scanned along the y-direction.

[0173] Fig. 6C illustrates a cross-section of parallel light beams 122o outputted from a PIC or an SLO system as previously described herein. Here, the array of parallel light beams 122o comprises three light beams of three different wavelengths.

[0174] The first wavelength 160 may correspond to red light, the second wavelength 162 may correspond to blue light, and / or the third wavelength may correspond to green light.

[0175] Hence, a repeating wavelength pattern or color pattern (e.g., red, green, blue) is employed. In other words, the parallel light beams 122o incorporate a repeating sequence of colors repeated throughout the array of parallel light beams 122o. Further, the sequence of repeating wavelengths may comprise further wavelengths, e.g., a fourth wavelength (such as near near-infrared).

[0176] Similarly as in Figs. 6A-B, the parallel light beams 122o are configured to be scanned along the y-direction.

[0177] Fig. 7 illustrates a diagram of method 2000 for optically scanning a retina. The method 2000 comprises: outputting 2100 a plurality of light beams in parallel to each other to the retina via a plurality of interface components, receiving 2200, at the plurality of interface components, response signals based on the outputted plurality of light beams, and detecting 2300 the response signals at a plurality of photodetectors.

[0178] The method 2000 may comprise using a PIC, e.g., as described in relation to Figs. 1A or 2A-B for outputting 2100 the plurality of light beams in parallel to each other to the retina. The PIC may, e.g., be integrated in an SLO system as described in relation to any one of Figs. 3A-B, 4, and 5.

[0179] The method 2000 further comprising: scanning the retina with a plurality different wavelengths, such as wavelengths corresponding to red, blue, green, and / or near-infrared. The retina may be scanned with the plurality of different wavelengths simultaneously, e.g., in one scan or sweep.

[0180] In the above the inventive concept has mainly been described with reference to a limited number of examples. However, as is readily appreciated by a person skilled in the art, other examples than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.

Claims

25CLAIMS1. A photonic integrated circuit, PIC, (100) for scanning laser ophthalmoscopy, SLO, the PIC (100) comprising: a splitter (110), and a plurality of waveguide paths (120), wherein the splitter (110) is configured to receive a light signal (102), and split the light signal (102) into the plurality of waveguide paths (120), wherein each waveguide path (120) comprises: an interface component (122) configured to output a light beam (122o) and receive a response signal (122r) based on the outputted light beam (122o), and a photo detection module (124) configured to receive the response signal (122r) from the interface component (122), the photo detection module (124) comprising a photodetector (125) configured to detect the response signal (122r), wherein the interface components (122) of the waveguide paths (120) are configured to output the light beams (122o) in parallel to each other.

2. The PIC (100) according to claim 1 , wherein the PIC (100) further comprises a modulator (130), and wherein the light signal (102) is amplitude- modulated by the modulator (130) to prevent interference from ambient light and / or other sources.

3. The PIC (100) according to claim 1 or 2, further comprising an entry waveguide for guiding the light signal (102) to the splitter (110), wherein the entry waveguide comprises an entry splitter (150) configured to divert a portion of the light signal (102) to an entry photodetector (152) configured to monitor a power level of the light signal (102) and / or compensate for intensity variations in the light signal (102).

4. The PIC (100) according to any one of the preceding claims, wherein each interface component (122) comprises an absorber (123), wherein each absorber (123) is configured to absorb residual light and optionally act as a monitoring photodetector for monitoring a power level of the outputted light beam (122o).

5. The PIC (100) according to any one of the preceding claims, wherein each photo detection module (124) further comprises a filter configured to filter the response signal (122r), wherein the filter (126) is configured to pass only a specific wavelength of light to the photodetector (125), and / or block excitation light from being received by the photodetector (125).

6. The PIC (100) according to any one of the preceding claims, wherein the interface components (122) are 2-by-2 splitters, polarization beam splitters, and / or optical circulators.

7. The PIC (100) according to any one of the preceding claims, wherein the PIC (100) comprises 2 to 2048 waveguide paths (120).

8. A scanning laser ophthalmoscopy, SLO, system (1000) comprising: a splitter (110), and a plurality of waveguide paths (120), wherein the splitter (110) is configured to receive a light signal (102), and split the light signal (102) into the plurality of waveguide paths (120), wherein each waveguide path (120) comprises: an interface component (122) configured to output a light beam (122o) and receive a response signal (122r) based on the outputted light beam (122o), and a photo detection module (124) configured to receive the response signal (122r) from the interface component (122), the photo detection module (124) comprising a photodetector (125) configured to detect the response signal (122r), wherein the interface components (122) of the waveguide paths (120) are configured to output the light beams (122o) in parallel to each other.

9. The SLO system (1000) according to claim 8, further comprising: a scanning mirror (200), and imaging optics (300).

10. The SLO system (1000) according to claim 9, wherein the scanning mirror (200) and the imaging optics (300) are configured to direct the outputted plurality of parallel light beams (122o) to a retina (400), and to direct theplurality of response signals (122r) from the retina (400) to the interface components (122).11 . The SLO system (1000) according to any one of claims 8-10, comprising a plurality of PICs (100) according to any one of claims 1 -7, each PIC (100) being configured to handle a specific wavelength, such as a wavelength corresponding to red, blue, green, or near-infrared.

12. The SLO system (1000) according to any one of claims 8-11 , wherein the SLO system (1000) is integrated with an Optical Coherence Tomography, OCT, module (600), the OCT module (600) being configured to use light to capture three-dimensional images from within biological tissues such as a retina (400).

13. The SLO system (1000) according to any one of claims 8-12, wherein the SLO system (1000) is integrated with a Hyperspectral Imaging, HSI, module (700), the HSI module (700) being configured to capture and process information across multiple wavelength bands.

14. A method (2000) for optically scanning a retina, the method (2000) comprising: outputting (2100) a plurality of light beams in parallel to each other to the retina via a plurality of interface components,Receiving (2200), at the plurality of interface components, response signals based on the outputted plurality of light beams, and detecting (2300) the response signals at a plurality of photodetectors.

15. The method (2000) according to claim 14 further comprising: scanning the retina with a plurality of different wavelengths, such as wavelengths corresponding to red, blue, green, and / or near-infrared.

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