A spectral domain OCT configuration that enhances sample arm signal
By employing a combination of N×M couplers and circulators in the spectral domain OCT system and altering the optical path design, the problem of sample arm signal attenuation was solved, thereby improving the signal-to-noise ratio and maximizing the utilization of sample information.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SU ZHOU KA MEN HA SI JI GUANG JI SHU YOU XIAN ZE REN GONG SI
- Filing Date
- 2025-09-30
- Publication Date
- 2026-05-29
Smart Images
Figure CN224302981U_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of spectroscopic isolation technology, and in particular to a spectral domain OCT structure for enhancing the signal of a sample arm. Background Technology
[0002] Spectral domain optical coherence tomography utilizes low-coherence interferometry to split the light emitted from the light source into two parts, which enter the reference arm and the sample arm respectively. The reference light returning along its original path and the backscattered light carrying sample depth information interfere within the coupler. The interference signal enters the spectrometer, enabling the detection of the interference spectral signal. After image processing, the interference spectrum carrying sample structural information can reconstruct the depth direction information of the sample under test. During the detection process, the splitting of the light emitted from the light source and the interference of the returning light from the two arms are all completed in the same location, namely the fiber coupler. When the light source power is constant, only a small portion of the sample light is scattered back to form the signal light when it illuminates the sample under test. For the reference arm, since the light illuminates a mirror, almost all of it is reflected back to form the reference light. At this point, the shot noise of the system mainly comes from the reference light. To maximize the system signal-to-noise ratio, commercially available 50:50 couplers are typically used to approach the theoretical optimal value, while devices such as polarization controllers are added to the reference arm to fine-tune the intensity of the reference light. Currently, 2×2 couplers with a splitting ratio of 50:50 are commonly used in the market for beam splitting, such as... Figure 1 As shown, the 2×2 coupler (7) is connected between the light source emitter (1) and the spectrometer (6), as well as between the reference arm (4) and the sample arm. When the interference light passes through the 2×2 coupler, only 50% of the light can reach the spectrometer (6), which further weakens the already weak sample signal. Utility Model Content
[0003] This invention aims to at least solve the technical problems existing in the prior art, and innovatively proposes a spectral domain OCT structure to enhance the signal of the sample arm.
[0004] To achieve the above-mentioned objectives of this utility model, this utility model provides a spectral domain OCT structure for enhancing sample arm signals, including a light source emitter, a circulator, a coupler, a reference arm, a sample arm, and a spectrometer. The output terminal of the light source emitter is connected to the first terminal of the circulator, the second terminal of the circulator is connected to the input terminal of the coupler, the first output terminal of the coupler is connected to the input terminal of the reference arm, the second output terminal of the coupler is connected to the input terminal of the sample arm, and the third terminal of the circulator is connected to the input terminal of the spectrometer.
[0005] When the light emitted by the light source emitter enters the circulator through the first end of the circulator, it is output to the coupler through the second end of the circulator. The light is split by the coupler and enters the reference arm and the sample arm respectively. The reference light and the sample light returning along the original path interfere in the coupler and enter the second end of the circulator, and are transmitted to the spectrometer through the third end of the circulator.
[0006] In a preferred embodiment of this invention, the coupler is an N×M coupler, where N is a positive integer greater than or equal to 1, and N is a positive integer greater than or equal to 2. For example, it can be a 9×7 coupler, a 7×6 coupler, etc.; it can also be a 1×3 coupler with a splitting ratio of 30:30:40 or 10:10:80.
[0007] In a preferred embodiment of this invention, when N = M, an N×N coupler is used.
[0008] In a preferred embodiment of this utility model, the coupler is a 2×2 coupler.
[0009] In a preferred embodiment of this utility model, the coupler is a 1×2 coupler.
[0010] In a preferred embodiment of this invention, the spectral ratio is 50:50 or 80:20. However, the spectral ratio is not limited and can be any ratio.
[0011] In a preferred embodiment of this invention, the light source emitted by the light source emitter has an OCT wavelength.
[0012] In a preferred embodiment of this utility model, the wavelength of the light source emitted by the light source emitter is 850nm.
[0013] In a preferred embodiment of this invention, the circulator is a circulator with at least three ports.
[0014] In a preferred embodiment of this utility model, the circulator is a three-port circulator.
[0015] In summary, by adopting the above technical solution, this utility model can prevent the weakening of interference signals.
[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0017] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0018] Figure 1 This is a schematic diagram of the optical path structure connection in existing technology.
[0019] Figure 2 This is a schematic diagram of the structure of a three-port circulator in the prior art.
[0020] Figure 3 This is a schematic diagram of the optical path structure connection of this utility model. Detailed Implementation
[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0022] This invention provides a spectral domain OCT structure to enhance the signal of a sample arm, such as... Figure 3 As shown, the system includes a light source emitter 1, a three-port circulator 2, a 1×2 coupler 3 with a splitting ratio of 50:50 or 80:20, a reference arm 4, a sample arm 5, and a spectrometer 6. The output of the light source emitter 1 is connected to the first end of the three-port circulator 2, the second end of the three-port circulator 2 is connected to the input of the 1×2 coupler 3, the first output of the 1×2 coupler 3 is connected to the input of the reference arm 4, and the second output of the 1×2 coupler 3 is connected to the input of the sample arm 5; the third... The light source emitter 1 is connected to the input terminal of the spectrometer 6. When the light source emitter 1 emits a light source with a center wavelength of 850nm, it enters the three-port circulator 2 through the first terminal of the three-port circulator 2 and is output from the second terminal of the three-port circulator 2 to the 1×2 coupler 3. The light is split by the 1×2 coupler 3 and enters the reference arm 4 and the sample arm 5 respectively. The reference light and the sample light returning along the original path interfere with each other in the 1×2 coupler 3 and enter the second terminal of the three-port circulator 2. The light is then transmitted to the spectrometer 6 through the third terminal of the three-port circulator 2.
[0023] The three-port circulator includes three ports: the first port, the second port, and the third port. Figure 2As shown, a signal is input from terminal A of the three-port circulator and output from terminal B; a signal is input from terminal B of the three-port circulator and output from terminal C of the three-port circulator; a signal is input from terminal C of the three-port circulator and output from terminal A of the three-port circulator; a four-port circulator includes four ports, namely the first terminal, the second terminal, the third terminal, and the fourth terminal of the four-port circulator; correspondingly, an N-port circulator includes N ports, namely the first terminal, the second terminal, the third terminal, ..., the Nth terminal of the N-port circulator;
[0024] A 1×2 coupler includes an input terminal, a first output terminal, and a second output terminal; a 2×2 coupler includes a first input terminal, a second input terminal, a first output terminal, and a second output terminal; correspondingly, an N×2 coupler includes a first input terminal, a second input terminal, a third input terminal, ..., an Nth input terminal, and so on. The first output terminal and the second output terminal of the N×2 coupler; the N×M coupler includes the first input terminal, the second input terminal, the third input terminal, ..., the Nth input terminal, the first output terminal, the second output terminal, the third output terminal, ..., the Mth output terminal; wherein, the input terminal of the coupler can be used as both an input terminal and an output terminal, and the output terminal of the coupler can be used as both an output terminal and an input terminal.
[0025] This invention provides a spectral domain OCT structure to enhance the signal of a sample arm, such as... Figure 3As shown, the system includes a light source emitter 1, a four-port circulator 2, a 1×2 coupler 3, a reference arm 4, a sample arm 5, and a spectrometer 6. The output of the light source emitter 1 is connected to the first end of the four-port circulator 2, the second end of the four-port circulator 2 is connected to the input of the 1×2 coupler 3, the first output of the 1×2 coupler 3 is connected to the input of the reference arm 4, and the second output of the 1×2 coupler 3 is connected to the input of the sample arm 5. The third end of the four-port circulator 2 is connected to the input of the spectrometer 6. The fourth end of the circulator 2 is temporarily not connected; when the light source emitter 1 emits a light source with a center wavelength of 850nm, it enters the four-port circulator 2 through the first end of the four-port circulator 2, and is output from the second end of the four-port circulator 2 to the 1×2 coupler 3. The light is split by the 1×2 coupler 3 and enters the reference arm 4 and the sample arm 5 respectively; the reference light and the sample light returning along the original path interfere in the 1×2 coupler 3 and enter the second end of the four-port circulator 2, and are transmitted to the spectrometer 6 through the third end of the four-port circulator 2.
[0026] This invention provides a spectral domain OCT structure to enhance the signal of a sample arm, such as... Figure 3 As shown, the system includes a light source emitter 1, a three-port circulator 2, a 2×2 coupler 3, a reference arm 4, a sample arm 5, and a spectrometer 6. The output of the light source emitter 1 is connected to the first end of the three-port circulator 2. The second end of the three-port circulator 2 is connected to the input of the 2×2 coupler 3 (also called the first input of the 2×2 coupler). The first output of the 2×2 coupler 3 is connected to the input of the reference arm 4. The second output of the 2×2 coupler 3 is connected to the input of the sample arm 5. The third end of the three-port circulator 2 is connected to the input of the spectrometer 6. The light source is connected; the second input of the 2×2 coupler is not connected yet; when the light source emitter 1 emits a light source with a center wavelength of 850nm, it enters the three-port circulator 2 through the first end of the three-port circulator 2, and is output from the second end of the three-port circulator 2 to the 2×2 coupler 3. The light is split by the 2×2 coupler 3 and enters the reference arm 4 and the sample arm 5 respectively; the reference light and the sample light returning along the original path interfere in the 2×2 coupler 3 and enter the second end of the three-port circulator 2, and are transmitted to the spectrometer 6 through the third end of the three-port circulator 2.
[0027] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.
Claims
1. A spectral domain OCT structure for enhancing sample arm signals, comprising a light source emitter (1), a circulator (2), a coupler (3), a reference arm (4), a sample arm (5), and a spectrometer (6), characterized in that, The output end of the light source emitter (1) is connected to the first end of the circulator (2), the second end of the circulator (2) is connected to the input end of the coupler (3), the first output end of the coupler (3) is connected to the input end of the reference arm (4), the second output end of the coupler (3) is connected to the input end of the sample arm (5); the third end of the circulator (2) is connected to the input end of the spectrometer (6). When the light emitted by the light source emitter (1) enters the circulator (2) through the first end of the circulator (2), it is output to the coupler (3) through the second end of the circulator (2). The light is split by the coupler (3) and enters the reference arm (4) and the sample arm (5) respectively. The reference light and the sample light returning along the original path interfere in the coupler (3) and enter the second end of the circulator (2), and are transmitted to the spectrometer (6) through the third end of the circulator (2).
2. The spectral domain OCT structure for enhancing sample arm signals according to claim 1, characterized in that, Coupler (3) is an N×M coupler, where N is a positive integer greater than or equal to 1 and N is a positive integer greater than or equal to 2.
3. The spectral domain OCT structure for enhancing sample arm signals according to claim 2, characterized in that, When N = M, an N×N coupler is used.
4. The spectral domain OCT structure for enhancing sample arm signals according to claim 3, characterized in that, Coupler (3) is a 2×2 coupler.
5. The spectral domain OCT structure for enhancing sample arm signals according to claim 2, characterized in that, Coupler (3) is a 1×2 coupler.
6. The spectral domain OCT structure for enhancing sample arm signals according to claim 4 or 5, characterized in that, The spectrophotometric ratio is 50:50 or 80:
20.
7. The spectral domain OCT structure for enhancing sample arm signals according to claim 1, characterized in that, The light source emitted by the light source emitter (1) has an OCT wavelength.
8. The spectral domain OCT structure for enhancing sample arm signals according to claim 7, characterized in that, The light source emitted by the light source emitter (1) has a wavelength of 850nm.
9. The spectral domain OCT structure for enhancing sample arm signals according to claim 1, characterized in that, The circulator (2) is a circulator with at least three ports.
10. The spectral domain OCT structure for enhancing sample arm signals according to claim 8, characterized in that, The circulator (2) is a three-port circulator.