Spectrum detector and optical communication equipment

Abstract

The utility model relates to the technical field of optical communication, in particular to a spectrum detector and optical communication equipment. The spectrum detector comprises a double-fiber collimator used for inputting a detection light signal; the beam splitter prism is positioned on the light emitting side of the double-fiber collimator, and the light incident surface of the beam splitter prism is over against the light emitting side of the double-fiber collimator; the fixed spectroscope is positioned on one side, far away from the double-fiber collimator, of the beam splitter prism; the movable spectroscope is positioned on the reflected light emergent side of the beam splitter prism and can be close to or far away from the beam splitter prism along the light emergent direction of the beam splitter prism; the first photoelectric detector is located on the side, away from the movable spectroscope, of the beam splitter prism; the second photoelectric detector is located on the side, away from the beam splitter prism, of the fixed beam splitter. The volume of the spectrum detector can be effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of optical communication technology, and in particular to a spectral detector and an optical communication device. Background Technology

[0002] Spectroscopic detection devices have important applications in many fields; however, traditional spectroscopic detection devices often face the problems of large size and complex optical path systems. Taking spectroscopic analysis instruments as an example, these instruments typically require a large space to accommodate complex optical components and precision mechanical structures. These components and structures together constitute a large optical path system used to achieve functions such as light dispersion, focusing, and imaging. The complex optical path system not only increases the size and weight of the instrument but also makes the assembly and debugging process cumbersome and imposes high requirements on the operating environment. Utility Model Content

[0003] This utility model provides a spectral detector and an optical communication device to solve the problems of large size and complex structure of spectral detectors.

[0004] This utility model discloses a spectral detector, comprising:

[0005] A dual-fiber collimator is used to input the probe light signal;

[0006] The beam splitter is located on the light-emitting side of the dual-fiber collimator, with its light-incident surface facing the light-emitting side of the dual-fiber collimator.

[0007] A fixed beam splitter is located on the side of the beam splitter prism furthest from the dual-fiber collimator.

[0008] A movable beam splitter is located on the light-emitting side of the beam splitter prism and can move closer to or further away from the beam splitter prism along the light-emitting direction of the beam splitter prism.

[0009] The first photodetector is located on the side of the beam splitter away from the movable beam splitter.

[0010] The second photodetector is located on the side of the fixed beam splitter away from the beam splitter prism.

[0011] Optionally, the fixed beam splitter is located at the waist of the dual-fiber collimator.

[0012] Optionally, the first distance between the fixed beam splitter and the beam splitter prism is equal to the initial position of the movable beam splitter and the second distance between the beam splitter prisms.

[0013] Optionally, the incident angle of the beam splitter is 45 + / - 10°; the incident angles of the movable beam splitter and the fixed beam splitter are + / - 10°.

[0014] Optionally, the beam splitter has a beam splitting ratio of 1:2 and a polarization maintaining value >25dB; the fixed beam splitter has a beam splitting ratio of 1:1, and the movable beam splitter has a beam splitting ratio of 1:1.

[0015] Optionally, the first photodetector and the second photodetector are avalanche diodes and are packaged using a lens method.

[0016] Optionally, the dual-fiber collimator includes:

[0017] Two fiber optic pigtails, a collimating lens, and a beam splitter are arranged sequentially along the direction of light transmission.

[0018] Optionally, the collimating lens is a long focal length lens;

[0019] The spectral ratio of the spectral splitting film does not exceed 99:1.

[0020] Optionally, the movable beam splitter includes:

[0021] Piezoelectric ceramic and a beam splitter attached to the surface of the piezoelectric ceramic.

[0022] This utility model also discloses an optical communication device, including the spectral detector described above.

[0023] The beneficial effects of the spectral detector provided in this embodiment of the present invention are as follows:

[0024] The beam splitter is located on the output side of the dual-fiber collimator. After the detection light signal is input to the beam splitter, part of it is reflected to the movable beam splitter, and the other part is transmitted to the fixed beam splitter. A portion of the light signal reflected to the movable beam splitter is reflected back to the beam splitter, while a portion of the light signal transmitted to the fixed beam splitter is detected by the first photodetector, and the other portion is reflected back to the beam splitter. Thus, the two light signals are combined into a single beam within the beam splitter and emitted to the second photodetector. Since the position of the movable beam splitter is adjustable, the phase difference between the two light signals can be adjusted to meet the interference condition, resulting in interference. The second photodetector can then acquire the interference spectrum based on the interference signal, and the signal spectrum of the input light signal can be obtained from the interference spectrum. By setting the beam splitter so that the dual-fiber collimator, fixed beam splitter, movable beam splitter, first photodetector, and second photodetector are all arranged around the beam splitter, the structure is simple and highly integrated, effectively reducing the size of the spectral detector. Attached Figure Description

[0025] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0026] Figure 1This is a schematic diagram of the structure of an embodiment of the spectral detector provided by this utility model;

[0027] Figure 2 This is an interference spectrum obtained by a spectral detector in one embodiment of the present invention;

[0028] Figure 3 Based on Figure 2 The signal spectrum obtained from the interference spectrum is shown.

[0029] The labels for the attached figures are as follows:

[0030] 10. Spectrometer; 11. Dual-fiber collimator; 111. Fiber optic pigtail; 112. Collimating lens; 113. Beam splitter; 12. Beam splitter prism; 13. Fixed beam splitter; 14. Movable beam splitter; 141. Piezoelectric ceramic; 142. Mirror; 15. First photodetector; 16. Second photodetector. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0032] Please see Figure 1 , Figure 1 This is a schematic diagram of an embodiment of the spectral detector provided by this utility model. The spectral detector 10 includes a dual-fiber collimator 11, a beam splitter 12, a fixed beam splitter 13, a movable beam splitter 14, a first photodetector 15, and a second photodetector 16.

[0033] The dual-fiber collimator 11 connects two optical fibers, one of which is the input fiber and the other is the output fiber. The input fiber provides the input optical signal, and the dual-fiber collimator 11 splits the input optical signal, separating a very small portion as the probe optical signal for spectral detection. The remaining optical signal continues to be transmitted as the input optical signal through the output fiber.

[0034] The beam splitter 12 is located on the light-emitting side of the dual-fiber collimator 11. In this way, the probe light signal output by the dual-fiber collimator 11 can be input into the beam splitter 12 and be reflected and transmitted at the beam splitting surface of the beam splitter 12. According to the beam splitting ratio of the beam splitting film on the beam splitting surface, part of the probe light signal will be reflected out of the beam splitter 12, and the remaining part of the probe light signal will be emitted through the beam splitter 12.

[0035] The fixed beam splitter 13 is located on the side of the beam splitter prism 12 away from the dual-fiber collimator 11. The probe light signal transmitted from the beam splitter prism 12 is sent to the fixed beam splitter 13. The fixed beam splitter 13 is provided with a beam splitting film, which can reflect part of this light signal and transmit the other part.

[0036] The movable beam splitter 14 is located on the light-emitting side of the reflected light of the beam splitter 12, so that a portion of the probe light signal reflected from the beam splitter 12 can be reflected back into the beam splitter 12 by the movable beam splitter 14.

[0037] The second photodetector 16 is located on the side of the fixed beam splitter 13 away from the beam splitter prism 12, so that the light signal transmitted through the fixed beam splitter 13 can be detected by the second photodetector 16.

[0038] The first photodetector 15 is located on the side of the beam splitter 12 away from the movable beam splitter. A portion of the light signal reflected by the movable beam splitter 14 will pass through the beam splitting surface of the beam splitter 12 and be denoted as light signal A. The light signal reflected by the fixed beam splitter 13 will reach the beam splitting surface of the beam splitter 12, and a portion of the light signal will be reflected by the beam splitting surface, denoted as light signal B. By adjusting the position of the movable beam splitter 14, the optical path difference between light signal A and light signal B can satisfy the interference condition. Therefore, the phase difference between light signal A and light signal B also satisfies the interference condition. Since light signal A and light signal B are both branches of the probe light signal, they are from the same source and have the same polarization, and there is a controllable optical path difference (phase difference) after beam combining. Therefore, by adjusting the position of the movable beam splitter 14, light signal A and light signal B can interfere.

[0039] The interference light signal generated after combining light signals A and B will be received by the first photodetector 15, and the second photodetector 16 can detect the light signal transmitted from the fixed beam splitter 13. Since the splitting ratios of the beam splitter 12, the fixed beam splitter 12, and the movable beam splitter 14 are all known, the second photodetector 16 can calculate the intensity of the interference light signal based on the detected light signal. Therefore, it can perform noise suppression based on the result of the first photodetector 15, and then perform a Fourier transform based on the spectrum of the interference light signal detected by the second photodetector 16 to obtain the spectrum of the input light signal corresponding to the detected light signal.

[0040] In one implementation scenario, the beam splitter prism 12 has a splitting ratio of 1:2, the fixed beam splitter 13 has a splitting ratio of 1:1, and the movable beam splitter has a splitting ratio of 1:1. Assume the probe light signal provided by the bilinear collimator is... After passing through the beam splitter, The beam is split into two beams, with 2 / 3 being transmitted light. The reflected light is 1 / 3 The reflected light, after being split by the movable beam splitter 14, will pass through the beam splitter prism again, with 1 / 3 of the light signal reaching the second photodetector. ×1 / 2×2 / 3=1 / 9 A portion of the transmitted light is reflected by the fixed beam splitter and then returns to the beam splitter; this portion of the light signal is 2 / 3. ×1 / 2=1 / 3 Another portion was detected by the first photodetector; this portion of the light signal is... =2 / 3 ×1 / 2=1 / 3 1 / 3 The optical signal is further split at the beam-splitting surface of the beam-splitting prism, with 1 / 3 being reflected to the second photodetector, which is 1 / 9. With 1 / 9 Optical signals are generated after interference. The signal is transmitted to the second photodetector.

[0041] The intensity of the light signals detected by the first photodetector 15 and the second photodetector 16 satisfy the following relationship:

[0042]

[0043]

[0044] in, The light intensity detected by the first photodetector does not contain interference terms and only reflects the intensity of the light source and environmental noise. The light intensity detected by the second photodetector includes interference terms. τ represents the corresponding optical path time difference in the coherent optical path, and is related to the optical path difference. The relationship is: τ= / c (c is the speed of light). Wavelength, for The optical power at a given point characterizes the intensity distribution of different wavenumber (or wavelength) components in the incident light, which is called the interference spectrum. The signal spectrum of the input optical signal can be obtained through this interference spectrum. Please refer to [further details needed]. Figure 2 and Figure 3 , Figure 2 This is an interference spectrum obtained by a spectral detector in one embodiment of the present invention. Figure 3 Based on Figure 2 The signal spectrum obtained from the interference spectrum is shown.

[0045] Differential operations are used to eliminate noise and ensure... Unaffected by zero-frequency interference. The beam splitter prism 12 has a splitting ratio of 1:2, the fixed beam splitter 13 has a splitting ratio of 1:1, and the movable beam splitter 14 has a splitting ratio of 1:1, ensuring that the light intensities of the two interfering beams are equal (both 1 / 9). This results in a larger amplitude and more obvious peak value for the interference term, and also facilitates difference operations.

[0046] In one implementation scenario, the polarization maintaining value of the beam splitter 12 is >25dB, which can control polarization crosstalk within 0.3%, ensuring interference stability and thus obtaining higher spectral accuracy and reliability.

[0047] In one implementation scenario, the beam waist position of the dual-fiber collimator 11 is determined. The beam waist is the position where the beam diameter is smallest and the wavefront curvature is approximately flat within the Gaussian beam. The fixed beam splitter 13 is located at the beam waist position of the dual-fiber collimator 11, where the beam size is smallest. The wavefront curvature of the light signal reflected by the fixed beam splitter 13 is strictly matched with the light signal incident on the fixed beam splitter 13, which can also avoid energy loss or stray light interference caused by beam diffusion.

[0048] The movable beam splitter 14 can also be set to the initial position at the waist of the dual-fiber collimator 11 to ensure that the two interfering light signals have consistent wavefront curvature and form high-contrast interference fringes.

[0049] In one implementation scenario, the first distance between the fixed beam splitter 13 and the beam splitter prism 12 is equal to the second distance between the initial position of the movable beam splitter 14 and the beam splitter prism 12. This ensures that the initial optical path difference is 0, and the phase difference between the two light signals incident on the second photodetector 16 is 0. The movable beam splitter 14 is adjusted based on the initial position to avoid phase shift caused by the initial optical path difference, improve the contrast of interference fringes, reduce the complexity of phase correction during spectral reconstruction, and reduce the impact of environmental disturbances on the phase.

[0050] In one implementation scenario, the incident angle of the beam splitter 12 is 45 + / - 10°; the incident angles of the movable beam splitter 14 and the fixed beam splitter 13 are + / - 10°. When the incident angle of the beam splitter 12 is 45°, the beam splitting ratio has the lowest polarization sensitivity. An incident angle of 0° can reduce energy loss during optical signal transmission. The ±10° angle range can accommodate assembly errors and beam divergence angles.

[0051] In one implementation scenario, the first photodetector 15 and the second photodetector 16 are avalanche diodes and are packaged using a lens method. The APD utilizes the avalanche multiplication effect (gain coefficient M≈ This device can convert a single photon into a measurable current, making it suitable for pW-level low-light detection. The lens focuses the interference beam onto the sensitive area of ​​the APD (typically 50-100 μm in diameter), improving light energy utilization, reducing ambient light interference, and enhancing the signal-to-noise ratio. The first photodetector 15 and the second photodetector 16 can be from the same batch of APDs, with minimal differences and consistent gain, effectively improving spectral accuracy.

[0052] In one implementation scenario, the movable beam splitter 14 includes a piezoelectric ceramic 141 and a beam splitter lens 142 mounted on the surface of the piezoelectric ceramic 141. When a voltage is applied to the piezoelectric ceramic 141, it undergoes axial deformation, thereby driving the beam splitter lens 142 to move closer to or further away from the mirror surface of the beam splitter prism 12. Under voltage drive, the piezoelectric ceramic 141 can produce a nanometer-level displacement with a typical step of 0.1 nm, directly corresponding to the optical path difference adjustment accuracy.

[0053] In one implementation scenario, the dual-fiber collimator 11 includes: two fiber optic pigtails 111 arranged sequentially along the light transmission direction, a collimating lens 112, and a beam splitter 113. One fiber optic pigtail 111 is used to input the input optical signal. The input optical signal is incident on the collimating lens 112, where it is collimated before being input to the beam splitter 113. The beam splitter 113 has a splitting ratio of no more than 99:1, meaning that most of the light is reflected by the beam splitter 113 and transmitted through the other fiber optic pigtail 111. A very small portion passes through the beam splitter 113 and is emitted as a probe light signal.

[0054] As described above, in this embodiment, the beam splitter is located on the output side of the dual-fiber collimator. After the probe light signal is input to the beam splitter, part of it is reflected to the movable beam splitter, and the other part is transmitted to the fixed beam splitter. A portion of the light signal reflected to the movable beam splitter is reflected back to the beam splitter, while a portion of the light signal transmitted to the fixed beam splitter is detected by the first photodetector, and the other portion is reflected back to the beam splitter. Thus, the two light signals can be combined into a single beam in the beam splitter and emitted to the second photodetector. Since the position of the movable beam splitter is adjustable, adjusting its position can ensure that the phase difference between the two light signals satisfies the interference condition, resulting in interference. The second photodetector can obtain the interference spectrum based on the interference light signal, and from the interference spectrum, the signal spectrum of the input light signal can be obtained. By using the beam splitter, the dual-fiber collimator, fixed beam splitter, movable beam splitter, first photodetector, and second photodetector are all arranged around the beam splitter, resulting in a simple structure with high integration, effectively reducing the size of the spectral detector.

[0055] This invention also provides an optical communication device, including the spectral detector described above. The spectral detector has a simple structure and high integration, effectively reducing its size and making the overall design of the optical communication device more compact, thus adapting to more space-constrained application scenarios.

[0056] It should be understood that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of this utility model.

Claims

1. A spectral detector, characterized in that, include: A dual-fiber collimator is used to input the probe light signal; The beam splitter is located on the light-emitting side of the dual-fiber collimator, with its light-incident surface facing the light-emitting side of the dual-fiber collimator. A fixed beam splitter is located on the side of the beam splitter prism furthest from the dual-fiber collimator. A movable beam splitter is located on the light-emitting side of the beam splitter prism and can move closer to or further away from the beam splitter prism along the light-emitting direction of the beam splitter prism. The first photodetector is located on the side of the beam splitter away from the movable beam splitter; The second photodetector is located on the side of the fixed beam splitter away from the beam splitter prism.

2. The spectral detector according to claim 1, characterized in that, The fixed beam splitter is located at the waist of the dual-fiber collimator.

3. The spectral detector according to claim 2, characterized in that, The first distance between the fixed beam splitter and the beam splitter prism is equal to the second distance between the initial position of the movable beam splitter and the beam splitter prism.

4. The spectral detector according to claim 1, characterized in that, The incident angle of the beam splitter is 45 + / - 10°; the incident angles of the movable beam splitter and the fixed beam splitter are + / - 10°.

5. The spectral detector according to claim 4, characterized in that, The beam splitter has a beam splitting ratio of 1:2 and a polarization maintaining value >25dB; the fixed beam splitter has a beam splitting ratio of 1:1 and the movable beam splitter has a beam splitting ratio of 1:

1.

6. The spectral detector according to claim 1, characterized in that, The first photodetector and the second photodetector are avalanche diodes and are packaged using a lens method.

7. The spectral detector according to claim 1, characterized in that, The dual-fiber collimator includes: Two fiber optic pigtails, a collimating lens, and a beam splitter are arranged sequentially along the direction of light transmission.

8. The spectral detector according to claim 7, characterized in that, The collimating lens is a long focal length lens; The spectral ratio of the spectral splitting film does not exceed 99:

1.

9. The spectral detector according to claim 1, characterized in that, The movable beam splitter includes: Piezoelectric ceramic and a spectral-splitting film attached to the surface of the piezoelectric ceramic.

10. An optical communication device, characterized in that, Including the spectral detector as described in any one of claims 1-9.

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