KR101374354B1 - A optical coherence tomography using a comb source - Google Patents

Abstract

According to the method of Patent Document 1 as described above, there is a problem in that the configuration of the interferometer becomes complicated and the system cost becomes high. The present invention solves the above-mentioned problems and provides a low cost optical coherence tomography apparatus with a simple structure. It is for.
According to one embodiment of the present invention, a light source for use in an optical coherence tomography apparatus (OCT) is provided. The light source may use an arrayed waveguide grating (AWG) for splitting light from a superluminescent LED (SLD) into a plurality of wavelengths.

Description

Optical coherence tomography apparatus using light source of comb pattern spectrum {A OPTICAL COHERENCE TOMOGRAPHY USING A COMB SOURCE}

The present invention relates to an optical coherence tomography apparatus using a light source of a comb pattern spectrum, and more particularly, to an optical coherence tomography apparatus generated from a light source using an arrayed waveguide grating (AWG).

As a conventional imaging device, tomography imaging techniques such as X-ray CT, MRI, and ultrasound imaging are widely used in the medical field. These techniques are used for diagnosis of specific fields depending on different physical properties, resolution, penetration depth, and the like. Recently, researches on the development of medical diagnostic devices using light have been actively conducted. Optical coherence tomography (OCT) is the most representative of these. Optical coherence tomography was a technique based on Optical Coherence Domain Tomography (OCDR), and Duguay and Mattick first proposed the possibility of "seeing through skin" in the early 1971s. This technique uses cross-sectional imaging in a non-invasive, non-contact way, by measuring the optical reflection to measure the internal structure of biological tissues using the low coherence characteristics of the laser. . The coherence property of light reflected from a biological tissue is a function of time-of-flight information from the reflective boundary and back-scattering of tissue. information. This optical coherence tomography (OCT) is harmless because of the use of light, and the most common diagnostic field is the diagnosis of the retina of the eye.

The image technique of the OCT system is based on a Michelson interferometer and the output of the light source with low visibility is divided into two directions of the interferometer arm. The reflected light returned from the reference end and the backward scattered light from the sample end are again brought into interference and imaged through signal processing.

Spectral domain OCT, one of frequency-domain OCTs, has recently been developed and based on a line scan CCD (Charge Coupled Device) or an area CCD camera, it is possible to image a living body surface rather than a conventional time domain OCT It does not require physical optical path scanning equipment, so data processing speed is fast, real-time imaging is possible and signal-to-noise ratio is excellent.

However, such a spectral region OCT should increase the signal reflected from the biological tissue by irradiating a broadband light source with high energy in order to secure sufficient dynamic range (DR). There was a problem that the intensity of light that can be irradiated by the laser safety standard is limited. Accordingly, there is a problem in that the measurement depth of the biological tissue and the improvement of the noise-to-signal ratio are limited, and thus the sensitivity of the detection signal is lowered in measuring the biological tissue, thereby degrading the measurement efficiency of the biological tissue.

Referring to FIG. 1, in order to solve the above problem, the conventional patent document 1 discloses an optical coherence tomography system using a light source having a comb-pattern spectrum, in which the system generates coherence light. A light source unit 20, an interferometer unit 40 generating an interference fringe from the sample S measured by receiving the emitted light from the light source unit 20, and an interference fringe irradiated from the interferometer unit 40. And a processing unit 80 for converting an electrical signal into an electrical signal and imaging the collected data by detecting the signal of the receiving unit 60, wherein the light source unit 20 and the interferometer unit 40 are included. The comb-shaped filter unit 120 is installed between the plurality of beams, and the light emitted from the light source unit 20 is converted into a multi-wavelength comb light source.

Registered Patent Publication No. 10-0082656 (Patent Document 1)

The following description provides a simplified description of one or more embodiments in order to provide a basic understanding of embodiments of the invention. This section is not a comprehensive overview of all possible embodiments and is not intended to identify key elements or to cover the scope of all embodiments of all elements. Its sole purpose is to present the concept of one or more embodiments in a simplified form as a prelude to the more detailed description that is presented later.

According to the method of Patent Document 1 as described above, there is a problem in that the configuration of the interferometer becomes complicated and the system cost becomes high. The present invention solves the above-mentioned problems and provides a low cost optical coherence tomography apparatus with a simple structure. It is for.

According to one embodiment of the present invention, a light source for use in an optical coherence tomography apparatus (OCT) is provided. The light source may use an arrayed waveguide grating (AWG) for splitting light from a superluminescent LED (SLD) into a plurality of wavelengths.

The light source may further include a mirror for reflecting light branched from the AWG; And a semiconductor optical amplifier (SOA) for amplifying the light reflected from the mirror.

According to another embodiment of the present invention, an optical coherence tomography apparatus (OCT) is provided. The optical coherence tomography apparatus includes: a light source for splitting and outputting light from a superluminescent LED (SLD) into a plurality of wavelengths using an arrayed waveguide grating (AWG); Dividing the output light into a first light incident to the reference stage and a second light incident to the sample stage, and combining and outputting the first light reflected from the reference stage and the second light reflected from the sample stage Optical splitter for; It may include a detector for detecting the interference signal by receiving the light output from the optical splitter.

The light source may further include a mirror for reflecting light branched from the AWG; And a semiconductor optical amplifier (SOA) for amplifying the light reflected from the mirror.

According to the configuration of the present invention as described above, the optical coherence tomography apparatus can be produced in a low cost and simple configuration because it can be used to obtain the optical coherence tomography image by generating light of the comb-pattern spectrum in a cheap and simple configuration You can get the effect.

To the accomplishment of the foregoing and related ends, the one or more embodiments comprise the features hereinafter described and particularly pointed out in the claims. The following description and the annexed drawings set forth in further detail certain illustrative aspects of these embodiments. Those skilled in the art will appreciate that these aspects are merely exemplary and that various modifications are possible. Furthermore, the presented embodiments are construed to include both these embodiments and equivalents of such embodiments.

According to convention, various features of the drawings may not be shown by actual measurement. Thus, the dimensions of the various features may optionally be enlarged or reduced for simplicity. Also, some of the figures may be simplified for simplicity. Accordingly, the drawings may not show all components of the presented device (e.g., device) or method. Finally, like reference numerals may be used to indicate similar features throughout the description and drawings.
1 shows an optical coherence tomography apparatus according to a conventional patent document 1.
2 shows an optical coherence tomography apparatus according to an embodiment of the present invention.
3 illustrates a light source of an optical coherence tomography apparatus according to an embodiment of the present invention.
4A and 4B illustrate light of a comb-tooth spectrum generated by a light source of an optical coherence tomography apparatus according to an embodiment of the present invention.

Various embodiments are now described with reference to the drawings, wherein like reference numerals are used throughout the drawings to refer to like elements. For purposes of explanation, various descriptions are set forth herein to provide an understanding of the present invention. It is evident, however, that such embodiments may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing embodiments.

2 shows an optical coherence tomography apparatus according to an embodiment of the present invention.

Referring to FIG. 2, an optical coherence tomography apparatus (OCT) using a light source that generates a comb pattern spectrum is provided. The optical coherence tomography apparatus includes a light source 201 for splitting and outputting light from a superluminescent LED (SLD) into a plurality of wavelengths using an arrayed waveguide grating (AWG); The output light is divided into a first light incident to the reference stage 202 and a second light incident to the sample stage 203, and the first light and the sample stage 203 reflected from the reference stage 202. A light splitter 205 for combining and outputting the second light reflected from the light; It may include a detector 204 for receiving the light output from the optical splitter 205 to detect the interference signal.

AWG refers to a waveguide optical element that can act as a prism that can combine light of various wavelengths into one light beam and conversely split light of one light beam by wavelength.

AWGs have waveguide matrices with different radii of curvature, and the time that light passes through the waveguide depends on the length of the waveguide, that is, the radius of curvature of the waveguide, which causes the light to slap at the end of the waveguide matrix. As it passes, the light bends in a certain direction. Since the refractive index of the waveguide varies depending on the wavelength, the bending angle of the light also varies depending on the wavelength, thereby splitting the light of the plurality of wavelengths in the plurality of waveguides along the AWG end.

Such AWGs are advantageous in that they are inexpensive and easy to branch light of a desired wavelength.

The light source according to an embodiment of the present invention splits the light from the SLD into a plurality of wavelengths by using the AWG. The SLD may be the same as that used as the light source in the existing OCT, but is not limited thereto.

Light from the SLD is branched to have a plurality of wavelengths as it passes through the AWG, and is converted into light of a spectrum having a comb pattern, as shown in FIG. 3.

The light of the spectrum having the comb-tooth pattern as described above is very suitable for being incident on the sample stage because it has a low power and does not decrease the measurement efficiency of the biological tissue.

The light splitter 205 splits the light output from the light source 201 into a first light incident to the reference stage 202 and a second light incident to the sample stage 203. The light splitter 205 may be an optical coupler that splits the first light and the second light into 50:50. The split ratio of the first light and the second light is exemplary and not limited thereto, and may have various split ratios.

The first light split from the optical splitter 205 is incident on the reference stage 202, is reflected from the reference stage 202, and then inputs to the optical splitter 205. In addition, the second light split from the light splitter 205 is incident on the sample stage 203, and after being scanned, for example, a biological sample such as an eye at the sample stage 203, is reflected again to the light splitter 205. ) Is entered.

The light splitter 205 may combine the first light and the second light reflected from the reference end 202 and the sample end 203 and output the combined light.

Light output from the light splitter 205 is received from the detector 204. The detector 204 may detect an interference signal between the first light and the second light. For example, the detector 204 may be, but is not limited to, a linear CCD.

The interfering signal detected at the detector 204 may be signal processed by a computer to produce a tomographic image of the sample.

3 illustrates a light source of an optical coherence tomography apparatus according to an embodiment of the present invention. Referring to FIG. 3, the light source 201 includes an SLD 303 that emits light, an AWG 302 that splits the light emitted from the SLD 303 into a plurality of wavelengths, and light that is branched from the AWG. A mirror 301 for reflecting the light; A semiconductor optical amplifier (SOA) 304 for amplifying the light reflected from the mirror 301; And an isolator 305 for outputting the amplified light in one direction.

4A and 4B illustrate light of a comb-tooth spectrum generated by a light source of an optical coherence tomography apparatus according to an embodiment of the present invention.

Referring to FIG. 4A, the graph labeled 401 shows the light source output when no AWG is used.

On the other hand, according to the light source of the present invention for splitting light using AWG, the light is converted into the light of the comb-tooth spectrum like the portion indicated by 402, and filtering this part to the light of the comb-pattern spectrum such as 403 of FIG. 4B. I can convert it.

Since the light of the comb-pattern spectrum has a low power and does not reduce the measurement efficiency of biological tissue, it is suitable for use in an optical coherence tomography apparatus. Since the AWG is inexpensive, the light of the comb-pattern spectrum is manufactured using the AWG. The optical coherence tomography apparatus can be manufactured inexpensively and simply.

The description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features presented herein.

Claims (4)

delete delete As an optical coherence tomography device (OCT),
A light source for dividing and outputting light from a superluminescent led (SLD) into a plurality of wavelengths using an arrayed waveguide grating (AWG);
Dividing the output light into a first light incident to the reference stage and a second light incident to the sample stage, and combining and outputting the first light reflected from the reference stage and the second light reflected from the sample stage Optical splitter for;
Detector for detecting the interference signal by receiving the light output from the optical splitter
Lt; / RTI >
The light source includes:
A mirror for reflecting light branched from the AWG;
A semiconductor optical amplifier (SOA) for amplifying the light reflected from the mirror; And
Isolator for outputting the amplified light in one direction
It further comprises an optical coherence tomography device (OCT).
delete

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