A device for optical coherence tomography based on integrated photonics with simultaneous measurement in two wavelength ranges

Abstract

The utility model relates to the field of devices based on integrated photonics.The device for optical coherence tomography consists of a photonic integrated circuit, including a measuring arm for the first wavelength range, connected to the first tunable radiation source and including a series-connected first multimode coupler, an optical power divider and a second multimode coupler, a reference arm for the first wavelength range, including a series-connected first multimode coupler, a first delay line and a second multimode coupler, a measuring arm for the second wavelength range, connected to the second tunable radiation source and including a series-connected fourth multimode coupler, an optical power divider and a third multimode coupler, a reference arm for the second wavelength range, including a series-connected fourth multimode coupler, a second delay line and a third multimode coupler.The second and third multimode couplers are connected to the first and second balanced photodetectors, respectively, whose outputs are configured to be connected to external devices, and the output of the optical power divider is configured to output optical radiation toward the scanned sample. The technical result is improved image quality. 1 fig.

Description

[0001] The utility model relates to the field of devices based on integrated photonics, more specifically to the field of optical coherence tomography (OCT) systems.

[0002] A device for forming an image and a method for forming an image using OCT are known. The device comprises a switching unit that switches between a first state in which a return beam is combined with a reference beam (a state in which the return beam is conducted to a combining unit) and a second state (a state in which the path for the return beam is blocked or changed). A control unit controls the switching unit to change the first and second states. An interferometric information collection unit collects interferometric information about the return and reference beams using the reference beam or the return beam detected by the detecting unit in the second state and the combined beam. The invention ensures the production of a high-resolution tomographic image by removing noise caused by the autocorrelation component of the return beam [RU Patent No. 2503949, G01N 21 / 47, G01B 9 / 02, published [10.01.2014].

[0003] A differential OCT device is known that contains two radiation sources, two separation plates, optical mixers, a balanced photodetector, a reference arm, a sample arm, and a data processing and tomographic image formation unit, wherein both radiation sources generate radiation of a unique wavelength and have separate outputs for it, and the optical mixer is in optical communication with the reference arm and the sample arm.What is new in the developed differential OCT device is that both separator plates are in optical communication with an optical mixer, the support arm contains a rigidly articulated optical delay line and a collimating lens, wherein the optical delay line is fixed at a focal distance from this lens and is in optical communication with it, the sample arm contains a galvano-scanner and a focusing lens which are in optical communication, wherein the galvano-scanner mirror is placed in the plane of the focal distance from the focusing lens in such a way that with any rotation of the galvano-scanner mirror the focal distance is maintained, both separator plates are also optically connected to the inputs of a balanced photodetector, which is connected to a data processing and tomographic image formation unit via an amplifier, filter and analog-to-digital converter [RU Patent No. 158234, G01B 9 / 02, A61B 5 / 00, published 27.12.2015].

[0004] An OCT system is known, comprising an OCT light source, an OCT computing unit, a first OCT light guide, a second OCT light guide and a switching module. In this case, the light from the light source passes through the switching module, wherein the OCT light beam is transmitted to the input end of the first OCT light guide when the switching module is in its first state, and when the switching module is in its second state, the OCT light beam is transmitted to the input end of the second OCT light guide. Between the switching module and the plane of the object, a scanning device is located, correlated with the first OCT light guide. Moreover, the trajectory of the OCT beam of the first OCT light guide is introduced into the trajectory of the beam of a surgical microscope, and the trajectory of the OCT beam of the second OCT light guide is introduced into the trajectory of the beam of an endoscope, a surgical instrument or an OCT tip [RU Patent No. 2726272, G01B 9 / 02, published. [10.07.2020].

[0005] A device for OCT based on integrated photonics with a built-in trigger is known, containing a tunable radiation source connected to the input of a photonic integrated circuit, on which an optical trigger is located, connected to a first balanced photodiode, as well as optically connected measuring and reference arms connected to a second balanced photodiode, wherein the output of the first photodiode is connected to the synchronizing input of an analog-to-digital converter, and the output of the second - to the information input, the output of the analog-to-digital converter is configured to communicate with a personal computer [RU Patent No. 219337, A61B 6 / 08, G01B 9 / 02, published 12.07.2023].

[0006] The disadvantages of the given analogs are limited functionality due to the implementation of scanning in only one wavelength range.

[0007] The objective and technical result of the utility model is to improve the quality of OCT images by collecting diagnostic data simultaneously in two different wavelength ranges.

[0008] The stated problem is solved by an OCT device consisting of a photonic integrated circuit (PIC) including a measuring arm for a first wavelength range connected to a first tunable radiation source and including a first multimode coupler (MO), an optical power divider and a second MO connected in series, a reference arm for the first wavelength range including a first MO, a first delay line and a second MO connected in series, a measuring arm for a second wavelength range connected to a second tunable radiation source and including a fourth MO, an optical power divider and a third MO connected in series, a reference arm for the second wavelength range including a fourth MO, a second delay line and a third MO connected in series, wherein the second and third MO are connected to the first and second balanced photodetectors (BPD), respectively,the outputs of which are designed with the possibility of connection to external devices, and the output of the optical power divider is designed with the possibility of outputting optical radiation towards the scanned sample.

[0009] The essence of the utility model is explained by a drawing, which shows a structural diagram of a device for OCT, containing first and second tunable radiation sources 1 and 2, respectively, balanced photodetectors (BPD), 3 and 4, respectively, a photonic integrated circuit 5, on which the first through fourth multimode couplers (MO), 6, 7, 8 and 9, respectively, with a division ratio of 50 / 50, first and second delay lines, 10 and 11, respectively, and an optical power divider 12 are located.

[0010] The first MO 6, the optical power divider 12 and the second MO 7 connected in series constitute the measuring arm of the device for the first wavelength range, and the fourth MO 9, the optical power divider 6 and the third MO 8 connected in series constitute the measuring arm for the second wavelength range. The first MO 6, the first delay line 10 and the second MO 7 connected in series form the reference arm of the device for the first wavelength range, and the fourth MO 9, the second delay line 11 and the third MO 8 connected in series constitute the reference arm for the second wavelength range. The first tunable radiation source 1 is connected to the input of the optical frequency converter 5 via the first MO 6, and the second tunable radiation source 2 is connected to the input of the fourth MO 9. Optical communication between the measuring and reference arms for the first wavelength range is provided by the second MO 7, the outputs of which are connected to the first BFD 3.The optical connection between the measuring and reference shoulders for the second wavelength range is provided by the third MO 8, the outputs of which are connected to the second BFD 4. FIS 5 is the optical part of the device.

[0011] By using two wavelength ranges with different penetrating abilities and different resolutions, the quality of OCT images is improved.

[0012] The proposed device operates as follows: light from the first tunable radiation source 1 enters the first MO 6, where the first half of the optical signal is sent through the optical power divider 12 to the output of the device to the scanned sample, and the second half is sent to the first delay line 10. Further, in the second MO 7, the light coming from the first delay line 10 interferes with the backscattered light entering the input of the FIS 5 from the scanned sample through the optical power divider 12 and the first MO 6. The resulting optical OCT signal is converted into an electrical one using the first BFD 3. Simultaneously, at the output of the second channel in the second BFD 4, an electrical OCT signal obtained in the second wavelength range is similarly formed.

[0013] The first and second BFDs 3 and 4 are designed to accommodate analog-to-digital converters to enable processing of the received OCT electrical signal on a personal computer for visualization. They can be mounted on a single printed circuit board with the FIS via adhesive bonding or soldering, or directly on the FIS via inverted mounting using adhesive bonding. Tunable radiation sources 1 and 2 can be mounted in a similar manner.

[0014] The PIC is designed primarily for fabrication on a silicon nitride (Si3N4) production platform. The device also features flexible configuration and size adjustment of components placed on the PIC for implementation on other integrated photonics production platforms. The minimum PIC area required for implementation depends on the production platform and can be as small as 1 x 1 mm. 2For diagnostics using OCT, wavelength ranges of 1260-1360 nm and 820-880 nm can be used.

[0015] Thus, the proposed device, thanks to the integrated design of the optical part and due to the simultaneous collection of diagnostic data in two wavelength ranges, makes it possible to improve the quality of OCT images.

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