Far-field simulator and optical test system including same

Abstract

Disclosed in the present invention are: a far-field simulator that simulates a beam in a form of propagation from a remote point; and an optical test system including same. The far-field simulator comprises: a beam splitter configured to split an incident beam into a first beam and a second beam; a first far-field simulation unit configured to increase the curvature of a wavefront of the first beam passing through the beam splitter to simulate the first beam in a form of propagation from a remote point; and a second far-field simulation unit configured to increase the curvature of a wavefront of the second beam passing through the beam splitter to simulate the second beam in a form of propagation from a remote point, wherein the first beam emitted through the first far-field simulation unit is formed to have a greater diameter than the diameter of the second beam emitted through the second far-field simulation unit.

Description

Long-distance simulator and optical test system including same

[0001] The present invention relates to a long-distance simulator that simulates a beam in a form of propagation from a distant point and an optical test system including the same.

[0002] A far-field simulator (FFS) is a device that generally simulates a beam propagated over a long distance. Such far-field simulators can be particularly useful in technologies that transmit optical signals via space propagation between satellites.

[0003] Specifically, satellite payloads are equipped with various optical devices related to optical communications, which transmit optical signals between satellites via spatial propagation. Since testing an actual satellite is impossible during the design process for such optical communications, a method is needed to simulate the satellite's operating environment and test the optical communications of the optical devices on the payload in this simulated environment, thereby achieving a more accurate design.

[0004] Meanwhile, the satellite's payload may be equipped with a front-end optical system that primarily processes beams arriving from the outside, and a rear-end optical system that is positioned inside the payload and secondarily processes beams passing through the front-end optical system. In general, the diameter of the beam processed by the front-end optical system is formed to be relatively larger than the diameter of the beam processed by the rear-end optical system. In other words, the beams processed by the front-end optical system and the rear-end optical system equipped on the satellite's payload are formed to have different diameters.

[0005] However, conventional long-range simulators only output a single beam. Therefore, optical test devices utilizing these simulators require separate tests for the front-end and rear-end optical systems installed on satellite payloads. Consequently, conventional long-range simulators reduce the efficiency of satellite-mounted optical system testing.

[0006] One object of the present invention is to provide a long-distance simulator capable of simultaneously outputting a plurality of beams having different diameters, and an optical test system including the same.

[0007] In order to achieve the object of the present invention, a long-distance simulator according to one embodiment of the present invention includes a beam splitter configured to split an incident beam into a first beam and a second beam; a first long-distance simulator configured to increase the curvature of a wavefront of the first beam passing through the beam splitter and simulate the first beam in a form propagated from a distant point; and a second long-distance simulator configured to increase the curvature of a wavefront of the second beam passing through the beam splitter and simulate the second beam in a form propagated from a distant point, wherein the first beam emitted through the first long-distance simulator is formed to have a larger diameter than the second beam emitted through the second long-distance simulator.

[0008] According to an example related to the present invention, the first long-distance copying unit includes a first lens formed to focus the first beam passing through the beam splitter; a pinhole formed to pass the first beam focused in the form of a point source passing through the first lens; and a second lens configured to smooth the wavefront of the first beam diverging through the pinhole to form a collimated beam, and the second long-distance copying unit includes a first lens formed to focus the second beam passing through the beam splitter; a pinhole formed to pass the second beam focused in the form of a point source passing through the first lens; and a second lens configured to smooth the wavefront of the second beam diverging through the pinhole to form a collimated beam, and the size of the pinhole provided in the first long-distance copying unit may be formed smaller than the size of the pinhole provided in the second long-distance copying unit.

[0009] According to an example related to the present invention, the size of the pinhole provided in the second long-distance copying unit may be formed to be twice the size of the pinhole provided in the first long-distance copying unit.

[0010] According to an example related to the present invention, the long-distance copying machine may further include a first wavefront sensor unit configured to sense the wavefront flatness of the first beam output through the first long-distance copying unit in order to align the first lens, the pinhole, and the second lens of the first long-distance copying unit; and a second wavefront sensor unit configured to sense the wavefront flatness of the second beam output through the second long-distance copying unit in order to align the first lens, the pinhole, and the second lens of the second long-distance copying unit.

[0011] According to an example related to the present invention, the long-distance copying machine may further include a first alignment unit and a second alignment unit configured to align the first and second long-distance copying units, respectively, so that the first and second beams passing through the first and second long-distance copying units, respectively, have a flatness within a preset range based on the wavefront flatness of the first and second beams sensed by the first and second wavefront sensor units.

[0012] According to an example related to the present invention, the lengths of the optical paths of the first and second beams that are split by the beam splitter and incident on the first and second wavefront sensor units, respectively, are formed to be different from each other, and the beam splitter may be configured to split one of the first and second beams corresponding to one of the optical paths of the first and second beams that is formed to be longer at a higher ratio so as to reduce the difference in intensity of the first and second beams that are incident on the first and second wavefront sensor units, respectively.

[0013] An optical test system according to another embodiment of the present invention includes: the long-distance simulator; and an optical test unit configured to test an optical communication environment by receiving the first and second beams in an aligned state emitted from the long-distance simulator, wherein the optical test unit includes: a first beam splitter configured to split the first beam emitted through the first long-distance simulator so that one of the beams is incident on the first wavefront sensor unit and the other is incident on the optical test unit; and a second beam splitter configured to split the second beam emitted through the second long-distance simulator so that one of the beams is incident on the second wavefront sensor unit and the other is incident on the optical test unit.

[0014] According to an example related to the present invention, the optical test unit may be configured to receive one of the first and second beams in an aligned state emitted from the long-distance simulator, and may be configured to selectively test the optical communication environment for each of the first and second beams.

[0015] According to an example related to the present invention, the optical test unit may include a first optical test part and a second optical test part configured to receive the first and second beams in an aligned state emitted from the long-distance simulator, respectively, and to test the optical communication environment for the first and second beams, respectively.

[0016] According to an example related to the present invention, the optical test section may include a test for a Pointing, Acquisition and Tracking (PAT) algorithm designed to compensate for disturbance in an optical communication environment.

[0017] The effects of the present invention obtained through the above-described solution are as follows.

[0018] The long-distance simulator includes a beam splitter that splits an incident beam into a first beam and a second beam, a long-distance simulator that increases the curvature of the wavefront of the first beam split by the beam splitter to simulate the first beam in a form propagated from a distant point, and a long-distance simulator that increases the curvature of the wavefront of the second beam split by the beam splitter to simulate the second beam in a form propagated from a distant point, wherein the first beam emitted through the first long-distance simulator is formed to have a larger diameter than the second beam emitted through the second long-distance simulator.

[0019] According to the configuration of this long-distance simulator, since it is possible to simultaneously output first and second beams having different diameters, performance tests for multiple optical systems requiring different beam diameters can be performed more efficiently using a single long-distance simulator. In other words, multiple beams having different diameters can be simultaneously provided for optical tests of the front-end optical system and the rear-end optical system equipped on the satellite's payload.

[0020] Figure 1 is a conceptual diagram of a long-distance simulator and an optical test system equipped therewith according to one embodiment of the present invention.

[0021] Figure 2 is a conceptual diagram of the long-distance copying unit illustrated in Figure 1.

[0022] Hereinafter, a long-distance simulator (100) and an optical test system (10) including the same related to the present invention will be described in more detail with reference to the drawings.

[0023] In this specification, identical or similar components in different embodiments are given identical or similar reference numbers, and redundant descriptions thereof are omitted.

[0024] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0025] Fig. 1 is a conceptual diagram of a long-distance copying machine (100) and an optical testing system (10) equipped therewith according to one embodiment of the present invention. Fig. 2 is a conceptual diagram of the long-distance copying unit illustrated in Fig. 1.

[0026] Referring to FIGS. 1 and 2, the long-distance simulator (100) includes a beam splitter (110), a first long-distance simulator (120), and a second long-distance simulator (130).

[0027] The beam splitter (110) is configured to split the incident beam (B0) into a first beam (B1) and a second beam (B2). The beam (B0) incident on the beam splitter (110) may have a diameter of, for example, 4.56 mm. In addition, although not shown in the drawings of the present invention, the beam splitter (110) may be provided in multiple units. Accordingly, three or more beams may be split through the multiple beam splitters (110). Here, when the long-distance copying device is provided in multiple units, the long-distance copying device may further include a configuration that has the same or similar characteristics as the first and second long-distance copying devices (120, 130) and performs a function accordingly.

[0028] The first long-distance copying unit (120) is configured to increase the curvature of the wavefront of the first beam (B1) that has passed through the beam splitter (110) so as to copy the first beam (B1) in a form that has been propagated from a distant point.

[0029] The first long-distance copy unit (120) may include a first lens (121), a pinhole (122), and a second lens (123).

[0030] The first lens (121) is formed to focus the first beam (B1) that has passed through the beam splitter (110).

[0031] The pinhole (122) is formed to pass the first beam (B1) focused in the form of a point light source through the first lens (121). The pinhole (122) can be formed to remove the spatial high frequency component of the wavefront by passing the first beam (B1) focused in the form of a point light source through the first lens (121).

[0032] The second lens (123) is configured to make the wavefront of the first beam (B1) that passes through the pinhole uniform and diverge into a collimated beam. The collimated beam refers to a beam that is emitted when the optical system through which the first beam (B1) passes is aligned.

[0033] The second long-distance copying unit (130) is configured to increase the curvature of the wavefront of the second beam (B2) that has passed through the beam splitter (110) so as to copy the second beam (B2) in a form that has been propagated from a distant point. The second long-distance copying unit (130) may be configured to have the same or similar structure and perform functions accordingly as the first long-distance copying unit (120).

[0034] The second long-distance copying unit (130) may include a first lens (131), a pinhole (132), and a second lens (133). Here, the first lens (131) and the second lens (133) provided in the second long-distance copying unit (130) may be formed to have the same optical characteristics as the first lens (121) and the second lens (123) provided in the first long-distance copying unit (120). That is, the first and second long-distance copying units (120, 130) may be configured using the same two first lenses (121, 131) and the same two second lenses (123, 133).

[0035] The first lens (131) is formed to focus the second beam (B2) that has passed through the beam splitter (110).

[0036] The pinhole (132) is formed to pass the second beam (B2) focused in the form of a point light source through the first lens (131). The pinhole (132) can be formed to remove the spatial high frequency component of the wavefront by passing the second beam (B2) focused in the form of a point light source through the first lens (131).

[0037] The second lens (133) is configured to make the wavefront of the second beam (B2) that passes through the pinhole (132) even and diverge into a collimated beam. Here, the collimated beam refers to a beam that is emitted when the optical system through which the second beam (B2) passes is aligned.

[0038] Here, the first beam (B1) emitted through the first long-distance copy unit (120) is formed to have a larger diameter than the second beam (B2) emitted through the second long-distance copy unit (130).

[0039] In addition, in order to form the diameter of the first beam (B1) larger than the diameter of the second beam (B2), the size of the pinhole provided in the first long-distance copying unit (120) may be formed smaller than the size of the pinhole provided in the second long-distance copying unit (130).

[0040] For example, the size of the pinhole provided in the second long-distance copying unit (130) can be formed to be twice the size of the pinhole provided in the first long-distance copying unit (120). According to the configuration of the first and second long-distance copying units (120, 130) as described above, the diameter of the first beam (B1) emitted through the first long-distance copying unit (120) can be formed to be approximately twice the diameter of the second beam (B2) emitted through the second long-distance copying unit (130).

[0041] For example, the size of the pinhole (122) provided in the first long-distance copying unit (120) may be formed to be 25 μm, and the size of the pinhole (132) provided in the second long-distance copying unit (130) may be formed to be 50 μm. At this time, the diameter of the first beam (B1) emitted through the first long-distance copying unit (120) may be formed to be 49.6 mm, and the diameter of the second beam (B2) emitted through the second long-distance copying unit (130) may be formed to be 24.9 mm, which is about half of the diameter of the first beam (B1).

[0042] Meanwhile, the optical paths (B1a, B2a) formed between the first lens (121, 131) and the second lens (131, 133) of the first and second long-distance copying units (120, 130) may not be in a straight line. Accordingly, a mirror (M1, M2, M3, M4) may be provided between the first lens (121) and the second lens (123) of the first long-distance copying unit (120) to reflect the incident first beam (B1) in a specific direction so that the first beam (B1) passing through the first lens (121) proceeds toward the second lens (123), thereby forming the optical path (B1a) of the first beam (B1). Likewise, a mirror (M5, M6, M7, M8, M9) may be provided between the first and second lenses (131, 133) of the second long-distance copy unit (130) to form an optical path (B2a) of the second beam (B2) by reflecting the incident second beam (B2) and directing it toward the second lens (133).

[0043] Meanwhile, the satellite's payload may be equipped with a front-end optical system that primarily processes beams arriving from the outside, and a rear-end optical system that is arranged inside the payload and secondarily processes beams passing through the front-end optical system. The beam processed by the front-end optical system has a diameter that is relatively larger than the diameter of the beam processed by the rear-end optical system. Accordingly, the first beam (B1) output through the first and second long-distance copying units (120, 130) may be used to verify the performance of the front-end optical system equipped on the satellite's payload, and the second beam (B2) may be used to verify the performance of the rear-end optical system equipped on the satellite's payload.

[0044] Meanwhile, since the long-distance simulator (100) simulates a beam transmitted from a long distance, a high level of flatness of the wavefront of the emitted beam must be maintained. The long-distance simulator (100) may be provided with a first wavefront sensor unit (140) and a second wavefront sensor unit (150) that are arranged at the rear ends of the first and second long-distance simulators (120, 130) to maintain the flatness of the wavefront of the first and second beams (B1, B2) emitted from the first and second long-distance simulators (120, 130) and used for optical system alignment.

[0045] The first wavefront sensor unit (140) is configured to sense the wavefront flatness of the first beam (B1) emitted through the first long-distance copy unit (120) in order to align the first lens (121), pinhole (122), and second lens (123) of the first long-distance copy unit (120).

[0046] The second wavefront sensor unit (150) is configured to sense the wavefront flatness of the second beam (B2) output through the second long-distance copy unit (130) in order to align the first lens (131), pinhole (132), and second lens (133) of the second long-distance copy unit (130).

[0047] Meanwhile, the long-distance copy machine (100) may further include a first alignment unit (160) and a second alignment unit (170).

[0048] The first alignment unit (160) and the second alignment unit (170) can be configured to align the first and second long-distance copying units (120, 130), respectively, so that the first and second beams (B1, B2) that have passed through the first and second long-distance copying units (120, 130), respectively, have a flatness within a preset range based on the wavefront flatness of the first and second beams (B2) sensed by the first and second wavefront sensor units (140, 150).

[0049] The first alignment unit (160) and the second alignment unit (170) are configured with mounts that are respectively coupled to the optical systems constituting the first and second long-distance copy units (120, 130), and can provide the optical systems with a high degree of freedom for attitude adjustment.

[0050] In addition, the beam splitter (110) can be configured so that the ratio of the intensities of the first and second beams (B1, B2) incident on the first and second wave sensor units (140, 150), respectively, can be conveniently adjusted so that the intensities of the beams to be tested become the intensities of the beams to be tested.

[0051] Meanwhile, the lengths of the optical paths (B1a, B2a) of the first and second beams (B1, B2) that are split by the beam splitter (110) and incident on the first and second wave sensor units (140, 150), respectively, may be formed differently.

[0052] Here, the beam splitter (110) may be configured to split one of the first and second beams (B1, B2) corresponding to the longer optical path (B1a, B2a) of the first and second beams (B1, B2) at a higher ratio so as to reduce the difference in intensity of the first and second beams (B1, B2) incident on the first and second wave sensor units (140, 150), respectively. According to the structure of the beam splitter (110) as described above, in the process of aligning the optical systems of the first and second long-distance copying units (120, 130), by analyzing the wavefront flatness for the first and second beams (B1, B2) of similar intensity incident on the first and second wavefront sensor units (140, 150), considerations due to the intensity difference in the incident first and second beams (B1, B2) are excluded, so that the alignment work of the optical systems can be performed more effectively.

[0053] According to the configuration of the long-distance simulator (100) described above, since it is possible to simultaneously output the first beam (B1) and the second beam (B2) having different diameters, performance tests for multiple optical systems requiring different beam diameters can be performed more efficiently using a single long-distance simulator (100). That is, multiple beams having different diameters for optical tests of the front-end optical system and the rear-end optical system equipped on the satellite's payload can be provided simultaneously. In addition, the optical test unit of the optical test system (10) is configured to be capable of testing each of the multiple beams output from the long-distance simulator (100), so that verification work for multiple types of optical systems can be performed simultaneously.

[0054] Meanwhile, an optical testing system (10) according to one embodiment of the present invention includes a long-distance simulator (100) and an optical testing unit (12). In the following description of the optical testing system (10), any description of the long-distance simulator (100) that overlaps with the previously described content will be omitted for convenience of explanation.

[0055] The optical test section is configured to test the optical communication environment by receiving aligned first and second beams (B1, B2) emitted from a long-distance simulator (100).

[0056] And the optical test section includes a first beam splitter (12a) and a second beam splitter (12b).

[0057] The first beam splitter (12a) is configured to split the first beam (B1) emitted through the first long-distance copying unit (120) so that one of the first beams (B1) is incident on the first wavefront sensor unit (140) and the other is incident on the optical test unit.

[0058] The second beam splitter (12b) splits the second beam (B2) emitted through the second long-distance copy unit (130) so that one of the second beams (B2) is incident on the second wavefront sensor unit (150) and the other is incident on the optical test unit.

[0059] In addition, the optical test section may be configured to receive one of the first and second beams (B1, B2) in an aligned state emitted from a long-distance simulator (100), and may be configured to selectively test each optical communication environment for the first and second beams (B1, B2).

[0060] Meanwhile, the optical test section may be equipped with a first optical test part and a second optical test part configured to receive the aligned first and second beams (B1, B2) emitted from the long-distance simulator (100), respectively, and test the optical communication environment for the first and second beams (B1, B2), respectively.

[0061] Additionally, the optical test section may include testing of a Pointing, Acquisition and Tracking (PAT) algorithm designed to compensate for disturbances in an optical communication environment.

[0062] In addition, the optical test unit (12) configured for testing the PAT algorithm may include, for example, a first high-speed steering mirror, a second high-speed steering mirror, an optical lens, and an image acquisition device. The first high-speed steering mirror, the second high-speed steering mirror, the optical lens, and the image acquisition device may be sequentially arranged along the optical paths (B1a, B2a) of the first beam (B1) and the second beam (B2) emitted from the first and second long-distance copying units (120, 130). At this time, the optical paths (B1a, B2a) of the first and second beams (B1, B2) reflected and propagated by the first and second beam splitters (12a, 12b), respectively, may be configured to overlap at least partially or form separate optical paths without overlapping each other.

[0063] The first high-speed steering mirror may be configured to receive the first beam (B1) and generate jitter. The jitter is a phenomenon in which a digital pulse signal waveform is distorted along the time axis, and refers to a deviation in timing that provides an operating moment.

[0064] The second high-speed steering mirror may be configured to correct the jitter by receiving the first beam (B1) reflected from the first high-speed steering mirror.

[0065] The optical lens may be arranged on the optical path (B1a) of the first beam (B1) reflected from the second high-speed steering mirror, so as to form an optical path (B1a) of the first beam (B1) directed toward the image acquisition device.

[0066] The above image acquisition device is configured to acquire image information about the first beam (B1) incident through the optical lens. The optical test unit (12) may be configured to perform a test on the PAT algorithm based on the image information about the first beam (B1) obtained through the image acquisition device.

[0067] Meanwhile, the optical test system (10) may include a light source unit (11) arranged in front of a long-distance simulator (100) as shown in FIG. 1 and configured to generate a beam and transmit it to a long-distance simulator (120).

[0068] The light source unit (11) may include, for example, a light source generation unit (11a), a beam isolator (11b), and a collimator (11c).

[0069] The light source generating unit (11a) can be configured to generate a beam that travels in a specific direction, such as a laser.

[0070] The beam isolator (11b) can be configured to allow light generated from the light source generation unit (11a) to pass through when it moves in the direction of travel, and to block the beam that is reflected and returns toward the light source generation unit (11a).

[0071] The collimator (11c) can be configured to make the incident beam from the beam isolator (11b) incident and the passing incident beam parallel. Accordingly, the beam emitted from the light source unit (11) can be configured to proceed along the optical path in a collimated state and be incident on the long-distance copy unit (120).

[0072] The foregoing description is merely exemplary, and various modifications may be made by those skilled in the art to which the present invention pertains without departing from the scope and technical spirit of the described embodiments. The above-described embodiments may be implemented individually or in any combination.

Claims

1. A beam splitter configured to split an incident beam into a first beam and a second beam; A first long-distance simulating unit configured to increase the curvature of the wavefront of the first beam passing through the beam splitter and to simulate the first beam in a form propagated from a distant point; and A second long-distance simulating unit is included to increase the curvature of the wavefront of the second beam passing through the beam splitter and to simulate the second beam in a form propagated from a distant point, A long-distance copying machine, characterized in that the first beam emitted through the first long-distance copying unit has a larger diameter than the second beam emitted through the second long-distance copying unit.

2. In paragraph 1, The above first long-distance copy unit, A first lens formed to focus the first beam passing through the beam splitter; A pinhole formed to pass the first beam focused in the form of a point light source through the first lens; and It includes a second lens configured to make the wavefront of the first beam diverging through the pinhole uniform and into a collimated beam. The above second long-distance copy unit, A first lens formed to focus the second beam passing through the beam splitter; A pinhole formed to pass the second beam focused in the form of a point light source through the first lens; and It includes a second lens configured to make the wavefront of the second beam emitted through the pinhole uniform and make it a collimated beam. A long-distance copying machine, characterized in that the size of the pinhole provided in the first long-distance copying unit is smaller than the size of the pinhole provided in the second long-distance copying unit.

3. In paragraph 2, A long-distance copying machine, characterized in that the size of the pinhole provided in the second long-distance copying unit is twice the size of the pinhole provided in the first long-distance copying unit.

4. In paragraph 2, A first wavefront sensor unit configured to sense the wavefront flatness of the first beam emitted through the first long-distance copy unit in order to align the first lens, the pinhole, and the second lens of the first long-distance copy unit; and A long-distance copying machine characterized in that it further includes a second wavefront sensor unit configured to sense the wavefront flatness of the second beam output through the second long-distance copying unit in order to align the first lens, the pinhole, and the second lens of the second long-distance copying unit.

5. In paragraph 4, A long-distance copying machine further comprising a first alignment unit and a second alignment unit configured to align the first and second long-distance copying units, respectively, so that the first and second beams passing through the first and second long-distance copying units, respectively, have a flatness within a preset range based on the wavefront flatness of the first and second beams sensed by the first and second wavefront sensor units.

6. In paragraph 4, The lengths of the optical paths of the first and second beams, which are split by the beam splitter and incident on the first and second wave sensor units, respectively, are formed to be different from each other, A long-distance simulator characterized in that the beam splitter is configured to divide one of the first and second beams corresponding to a longer optical path of the first and second beams at a higher ratio so as to reduce the difference in intensity of the first and second beams incident on the first and second wavefront sensor units, respectively.

7. Long-distance copying machine according to Article 4; and An optical test unit is provided to test an optical communication environment by receiving the first and second beams in an aligned state emitted from the long-distance simulator. The above optical test section, A first beam splitter that splits the first beam emitted through the first long-distance copying unit so that one of the beams is incident on the first wavefront sensor unit and the other is incident on the optical test unit; and An optical test system characterized by including a second beam splitter that splits the second beam emitted through the second long-distance copying unit so that one of the beams is incident on the second wavefront sensor unit and the other is incident on the optical test unit.

8. In paragraph 7, An optical test system characterized in that the optical test section is configured to receive one of the first and second beams in an aligned state emitted from the long-distance simulator, and to selectively test the optical communication environment for each of the first and second beams.

9. In paragraph 7, The above optical test section, An optical test system characterized by comprising a first optical test part and a second optical test part configured to receive the first and second beams in an aligned state emitted from the long-distance simulator, respectively, and to test the optical communication environment for the first and second beams, respectively.

10. In paragraph 7, The above optical test section, An optical test system comprising a test for a Pointing, Acquisition and Tracking (PAT) algorithm designed to compensate for disturbances in an optical communication environment.

Images