Optical filter with independently adjustable central wavelength and full width at half maximum

Abstract

The invention relates to the technical field of optical filtering, and provides an optical filter with independently adjustable central wavelength and full width at half maximum, which comprises a first input port, a second input port, a polarized light beam combiner, an electro-optical crystal, a polarized light beam splitter, a first output port and a second output port, the first input port and the second input port are respectively used for receiving first horizontal polarized light and first vertical polarized light; the polarized light in the horizontal direction and the polarized light in the vertical direction pass through a polarized light beam combiner to obtain first light; the first light passes through an electro-optical crystal, the light refractive index of the electro-optical crystal is adjusted, and second light is obtained; the second light passes through the polarized light beam splitter to obtain second polarized light in the horizontal direction and second polarized light in the vertical direction; and the signals respectively enter the first output port and the second output port. The invention has the advantages that: the central wavelength and the full width at half maximum are independently adjustable, and the flexibility and the performance of an optical communication system are improved.

Description

Technical Field

[0001] The invention relates to the technical field of optical filtering, and in particular to an optical filter with a central wavelength and a half-maximum full width independently adjustable. Background Art

[0002] Current optical filter technology has some challenges and limitations in adjusting the center wavelength and half-maximum full width. The center wavelength of the laser is the wavelength corresponding to the center position of the half-maximum full width of the spectrum measured at a certain temperature and rated power. The half-maximum full width refers to the wavelength difference when the intensity on both sides of the spectrum peak drops to half of the peak. Traditional optical filters usually have a fixed center wavelength and half-maximum full width. Their adjustment is limited by material properties and design structure, and cannot be independently adjustable.

[0003] Traditional optical filters are instruments used for wavelength selection. They can select the required wavelength from a large number of wavelengths, and light other than this wavelength will be rejected. It can be used for wavelength selection, noise filtering of optical amplifiers, gain equalization, and optical multiplexing / demultiplexing. This limitation may limit the flexibility and applicability of the filter in some application scenarios. In some fields such as photonics, optical communications, and spectral analysis, it is necessary to flexibly adjust the center wavelength and half-width at half maximum of the filter according to specific needs to meet the requirements of different optical systems. However, traditional optical filter technology cannot meet this demand, resulting in technical defects and limitations in practical applications.

[0004] Therefore, how to provide an optical filter with independently adjustable central wavelength and half-width at half maximum is a technical problem that urgently needs to be solved in the current field. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an optical filter whose central wavelength and half-maximum full width are independently adjustable.

[0006] The present invention is implemented as follows: an optical filter with independently adjustable central wavelength and half-maximum full width, comprising:

[0007] a first input port, a second input port, a polarization light beam combiner, an electro-optical crystal, a polarization light beam splitter, a first output port, and a second output port;

[0008] The first input port and the second input port are used to receive a first horizontal polarized light and a first vertical polarized light respectively;

[0009] The horizontally polarized light and the vertically polarized light pass through the polarized light combiner to obtain a first light;

[0010] The first light passes through the electro-optic crystal, and the refractive index of the light of the electro-optic crystal is adjusted to obtain the second light;

[0011] The second light passes through the polarization beam splitter to obtain a second horizontal polarization light and a second vertical polarization light;

[0012] The second horizontal polarized light and the second vertical polarized light enter the first output port and the second output port respectively.

[0013] Further, the polarization light beam combiner is a first polarization beam splitter prism, and the polarization light beam splitter is a second polarization beam splitter prism.

[0014] Furthermore, the polarization beam combiner is a first YVO 4 wedge block, the polarization beam splitter is the second YVO 4 Wedge-shaped block.

[0015] Furthermore, it also includes an electric field control device, which is electrically connected to the electro-optical crystal and is used to adjust the refractive index of light of the electro-optical crystal through the action of an electric field.

[0016] Furthermore, the type of the electro-optical crystal is potassium dihydrogen phosphate or ammonium dihydrogen phosphate or lithium niobate or lithium tantalate.

[0017] Furthermore, it also includes a shell and an adjustment panel, the first input port, the second input port, the polarization light combiner, the electro-optical crystal, the polarization light splitter, the first output port, the second output port, and the electric field control device are all fixedly arranged inside the shell, the adjustment panel is electrically connected to the electric field control device, and the adjustment panel is fixedly arranged on the outer surface of the shell.

[0018] Furthermore, it also includes an optical wave splitter, an optical wave combiner, a first silicon optical modulator, a second silicon optical modulator, a first rotating plate, a second rotating plate, a third rotating plate, a first semiconductor optical amplifier, a second semiconductor optical amplifier, a first monitoring photodiode and a second monitoring photodiode;

[0019] The first output end of the optical wave splitter is connected to the input end of the first silicon optical modulator, and the output end of the first silicon optical modulator is connected to the first input port;

[0020] The second output end of the optical wave splitter is connected to the input end of the second silicon optical modulator, the output end of the second silicon optical modulator is connected to the input end of the first rotating plate, and the output end of the first rotating plate is connected to the second input port;

[0021] The first output port is connected to the input end of the first semiconductor optical amplifier, and the output end of the first semiconductor optical amplifier is connected to the first input end of the optical wave combiner;

[0022] The second output port is connected to the input end of the second rotating plate, the output end of the second rotating plate is connected to the input end of the second semiconductor optical amplifier, the output end of the second semiconductor optical amplifier is connected to the input end of the third rotating plate, and the output end of the third rotating plate is connected to the second input end of the optical wave combiner;

[0023] The monitoring end of the first monitoring photodiode is connected to the output end of the first semiconductor optical amplifier, and the monitoring end of the second monitoring photodiode is connected to the output end of the third rotating plate.

[0024] Compared with the background technology, the advantages of the present invention are: after the horizontally polarized light and the vertically polarized light are combined, they pass through the electro-optical crystal, and the electro-optical crystal changes the refractive index of the light through the action of the electric field, thereby changing the speed of the light. Since the frequency of the light remains unchanged, the central wavelength and half-maximum full width of the light will change, that is, the central wavelength and half-maximum full width of the light are independently adjustable, and the specific modulation effect depends on the type of the electro-optical crystal and the size of the external electric field; the optical filter of the present invention realizes independent adjustment of the central wavelength and half-maximum full width, thereby improving the flexibility and performance of the optical communication system; by changing the size of the electric field, the central wavelength and half-maximum full width of the light are modulated, the response speed is fast, and it is suitable for high-speed optical communication systems; the present invention has a simple structure and is easy to implement and integrate in existing optical systems; the optical filter of the present invention can be widely used in optical communication, optical sensors, optical signal processing and other fields, and provides new solutions for the design and optimization of optical communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0026] Figure 1 The structure of the optical filter of the present invention in which the central wavelength and the half-maximum full width are independently adjustable Figure 1 .

[0027] Figure 2 The structure of the optical filter of the present invention in which the central wavelength and the half-maximum full width are independently adjustable Figure 2 .

[0028] Figure 3 The structure of the optical filter of the present invention in which the central wavelength and the half-maximum full width are independently adjustable Figure 3 .

[0029] Figure 4It is a schematic diagram of the application of an optical filter with independently adjustable central wavelength and half-maximum full width of the present invention.

[0030] Figure numerals: first input port 11; first horizontal polarized light 111; second input port 12; first vertical polarized light 121; polarized light combiner 13; electro-optical crystal 14; first light 141; second light 142; polarized light beam splitter 15; first output port 16; second horizontal polarized light 161; second output port 17; second vertical polarized light 171; electric field control device 18; housing 19; adjustment panel 191; optical wave splitter 21; optical wave combiner 22; first silicon optical modulator 23; second silicon optical modulator 24; first rotating plate 25; second rotating plate 26; third rotating plate 27; first semiconductor optical amplifier 28; second semiconductor optical amplifier 29; first monitoring photodiode 210; second monitoring photodiode 220; laser 3; optical fiber 4; detector 5. DETAILED DESCRIPTION

[0031] The embodiment of the present invention provides an optical filter with independently adjustable center wavelength and half-width at half maximum, which overcomes the disadvantage that traditional optical filters in the background technology usually have fixed center wavelength and half-width at half maximum; the center wavelength and half-width at half maximum are independently adjustable, thereby improving the technical effect of the flexibility and performance of the optical communication system.

[0032] The overall idea of ​​the technical solution of the embodiment of the present invention is as follows:

[0033] The horizontally polarized light and the vertically polarized light enter the polarization beam combiner to obtain the first light, which passes through the electro-optical crystal and is rotated and reflected multiple times to reach the required central wavelength or half-height full width, and finally passes through the polarization beam splitter to output two beams of linear polarization perpendicular to each other.

[0034] Electro-optic crystals change the refractive index of light through the action of electric field, thereby changing the speed of light in the medium. Since the frequency of a specific light does not change, the central wavelength and half-maximum full width of the light will change, that is, the central wavelength and half-maximum full width of the light can be adjusted independently; the specific modulation effect depends on the type of electro-optic crystal and the size of the external electric field.

[0035] The refractive index (n) indicates the ratio of the speed of light to that of vacuum (or air) when it propagates in a medium. The relationship between frequency (f) and wavelength (λ) satisfies the following formula: v = fλ, where v represents the speed of light in the medium.

[0036] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] See also Figures 1 to 3 , Embodiment 1 of the present invention.

[0038] An optical filter with independently adjustable central wavelength and half-maximum full width, comprising:

[0039] A first input port 11, a second input port 12, a polarization light beam combiner 13, an electro-optical crystal 14, a polarization light beam splitter 15, a first output port 16 and a second output port 17;

[0040] The first input port 11 and the second input port 12 are used to receive a first horizontal polarized light 111 and a first vertical polarized light 121 respectively;

[0041] The first horizontal polarized light 111 and the first vertical polarized light 121 pass through the polarized light combiner 13 to obtain a first light 141;

[0042] The first light 141 passes through the electro-optical crystal 14, and the refractive index of the light of the electro-optical crystal 14 is adjusted to obtain the second light 142;

[0043] The second light 142 passes through the polarization beam splitter 15 to obtain a second horizontal polarized light 161 and a second vertical polarized light 171;

[0044] The second horizontal polarized light 161 and the second vertical polarized light 171 enter the first output port 16 and the second output port 17 respectively.

[0045] After the horizontally polarized light and the vertically polarized light are combined, they pass through the electro-optical crystal. The electro-optical crystal changes the refractive index of the light through the action of the electric field, thereby changing the speed of the light. Since the frequency of the light remains unchanged, the central wavelength and the half-maximum full width of the light will change, that is, the central wavelength and the half-maximum full width of the light are independently adjustable, and the specific modulation effect depends on the type of the electro-optical crystal and the size of the external electric field; the optical filter of the present invention realizes that the central wavelength and the half-maximum full width are independently adjustable, thereby improving the flexibility and performance of the optical communication system; by changing the size of the electric field, the central wavelength and the half-maximum full width of the light are modulated, the response speed is fast, and it is suitable for high-speed optical communication systems; the present invention has a simple structure and is easy to implement and integrate in existing optical systems; the optical filter of the present invention can be widely used in optical communication, optical sensors, optical signal processing and other fields, and provides a new solution for the design and optimization of optical communication systems.

[0046] The polarization beam combiner 13 is a first polarization beam splitter prism, and the polarization beam splitter 15 is a second polarization beam splitter prism. The design here is based on a polarization beam splitter prism (PBS). The polarization beam splitter prism uses a combination of a polarization filter and a semi-reflecting mirror to separate and reflect the incident light according to the direction of the electric field, generating two beams of linearly polarized light that are perpendicular to each other. The electro-optical crystal 14 changes the refractive index of light through the action of the electric field, thereby achieving modulation of the center wavelength and half-maximum full width of the optical signal. The specific modulation effect depends on the type of the electro-optical crystal 14, such as potassium dihydrogen phosphate, ammonium dihydrogen phosphate, lithium niobate, lithium tantalate, etc. and the size of the external electric field. The light modulated by the electro-optical crystal 14 passes through a polarization beam splitter prism (PBS) again. The polarization beam splitter prism (PBS) ensures that the output is two linearly polarized beams perpendicular to each other, and the center wavelength and half-maximum full width have reached the preset requirements.

[0047] The polarization beam combiner 13 is a first YVO 4 wedge block, the polarization beam splitter 15 is a second YVO 4 Wedge block. This technical solution is based on YVO 4 Wedge material design. Input light enters YVO 4 Wedge material. YVO 4 It is a birefringent crystal with a specific refractive index, which can emit two mutually perpendicular linear polarized light beams. The two mutually perpendicular linear polarized light beams enter the electro-optic crystal 14; the electro-optic crystal 14 modulates the optical signal through the electric field to adjust the central wavelength and the half-maximum full width. The light modulated by the electro-optic crystal 14 directly passes through the YVO 4 Wedge material output, due to YVO 4 Due to the birefringence characteristics of the Wedge material, the output light is still two linearly polarized beams perpendicular to each other, and the central wavelength and half-maximum full width meet the preset requirements.

[0048] It also includes an electric field control device 18, which is electrically connected to the electro-optical crystal 14 and is used to adjust the light refractive index of the electro-optical crystal 14 through the action of the electric field. The beneficial effect of this technical solution is that the central wavelength and the half-maximum full width are modulated by changing the size of the electric field, the response speed is fast, and it is suitable for high-speed optical communication systems.

[0049] The type of the electro-optical crystal 14 is potassium dihydrogen phosphate or ammonium dihydrogen phosphate or lithium niobate or lithium tantalate. The modulation effect of the central wavelength and the half-maximum full width of the light depends on the type of the electro-optical crystal 14 and the size of the external electric field.

[0050] It also includes a housing 19 and an adjustment panel 191, wherein the first input port 11, the second input port 12, the polarization light beam combiner 13, the electro-optical crystal 14, the polarization light beam splitter 15, the first output port 16, the second output port 17, and the electric field control device 18 are all fixedly arranged inside the housing 19, and the adjustment panel 191 is electrically connected to the electric field control device 18, and the adjustment panel 191 is fixedly arranged on the outer surface of the housing 19. The beneficial effect of this technical solution is that it is convenient for the staff to change the electric field of the electro-optical crystal 14 by operating the adjustment panel 191.

[0051] See also Figure 4 , Embodiment 2 of the present invention.

[0052] It also includes an optical wave splitter 21, an optical wave combiner 22, a first silicon optical modulator 23, a second silicon optical modulator 24, a first rotating plate 25, a second rotating plate 26, a third rotating plate 27, a first semiconductor optical amplifier 28, a second semiconductor optical amplifier 29, a first monitoring photodiode 210 and a second monitoring photodiode 220;

[0053] The first output end of the optical wavelength splitter 21 is connected to the input end of the first silicon optical modulator 23, and the output end of the first silicon optical modulator 23 is connected to the first input port 11;

[0054] The second output end of the optical wavelength splitter 21 is connected to the input end of the second silicon optical modulator 24, the output end of the second silicon optical modulator 24 is connected to the input end of the first rotating plate 25, and the output end of the first rotating plate 25 is connected to the second input port 12;

[0055] The first output port 16 is connected to the input end of the first semiconductor optical amplifier 28, and the output end of the first semiconductor optical amplifier 28 is connected to the first input end of the optical wave combiner 22;

[0056] The second output port 17 is connected to the input end of the second rotating plate 26, the output end of the second rotating plate 26 is connected to the input end of the second semiconductor optical amplifier 29, the output end of the second semiconductor optical amplifier 29 is connected to the input end of the third rotating plate 27, and the output end of the third rotating plate 27 is connected to the second input end of the optical wave combiner 22;

[0057] The monitoring end of the first monitoring photodiode 210 is connected to the output end of the first semiconductor optical amplifier 28 , and the monitoring end of the second monitoring photodiode 220 is connected to the output end of the third rotating plate 27 .

[0058] The working method of this technical solution is as follows: the horizontal linear polarized light emitted by the laser 3 passes through the optical wave splitter 21 and is divided into two equal beams of the first horizontal light and the second horizontal light. The first horizontal light and the second horizontal light enter the first silicon optical modulator 23 and the second silicon optical modulator 24 respectively. After coherent drive modulation, the first horizontal light and the second horizontal light are both loaded with signals; then the first horizontal light enters the first input port 11, and the second horizontal light passes through the first rotating plate 25 to become vertical light and then enters the second input port 12. In the polarized light beam combiner 13, the horizontal light and the vertical light are combined to obtain the first light 141. The first light 141 passes through the first rotating plate 25 to become the vertical light and then enter the second input port 12. After passing through the electro-optical crystal 14, the central wavelength and the full width at half maximum are modulated, and the obtained second light 142 is divided into two equal beams of linear polarized light with perpendicular polarization directions at the polarization beam splitter 15, one of which is horizontal light, which is amplified by the power of the first semiconductor optical amplifier 28, and then enters the optical wave combiner 22, and the other vertical light is first converted into horizontal light by the second rotating plate 26, then amplified by the power of the second semiconductor optical amplifier 29, and then converted back into vertical light by the third rotating plate 27, and finally enters the optical wave combiner 22, in which the horizontal light and the vertical light are combined, and finally a high-power optical signal is emitted outward. It is used to compensate for the loss during the transmission of the optical fiber 4 and maintain the quality of the optical signal.

[0059] The light wave emitted by the laser 3 is not loaded with a signal, and needs to pass through a silicon optical modulator, through a coherent drive modulation method, that is, the external current and voltage signals are converted into parameters such as the intensity amplitude, phase, frequency, and polarization direction of the light wave, and the electrical signal data is loaded onto the light wave, thereby realizing optical transmission of the signal. The light emitted by the optical wave combiner 22 passes through the optical fiber 4 to the detector 5 at the receiving end, and the detector 5 converts the optical signal into an electrical signal for output.

[0060] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. An optical filter with independently adjustable central wavelength and half-width at half maximum, characterized in that: include: a first input port, a second input port, a polarization light beam combiner, an electro-optical crystal, a polarization light beam splitter, a first output port, and a second output port; The first input port and the second input port are used to receive a first horizontal polarized light and a first vertical polarized light respectively; The horizontally polarized light and the vertically polarized light pass through the polarized light combiner to obtain a first light; The first light passes through the electro-optic crystal, and the refractive index of the light of the electro-optic crystal is adjusted to obtain the second light; The second light passes through the polarization beam splitter to obtain a second horizontal polarization light and a second vertical polarization light; The second horizontal polarized light and the second vertical polarized light enter the first output port and the second output port respectively.

2. An optical filter with independently adjustable central wavelength and half-width at half maximum according to claim 1, characterized in that: The polarization light beam combiner is a first polarization beam splitter prism, and the polarization light beam splitter is a second polarization beam splitter prism.

3. The optical filter with independently adjustable central wavelength and half-width at half maximum according to claim 1, characterized in that: The polarization beam combiner is a first YVO4 wedge block, and the polarization beam splitter is a second YVO4 wedge block.

4. The optical filter with independently adjustable central wavelength and half-width at half maximum according to claim 1, characterized in that: It also includes an electric field control device, which is electrically connected to the electro-optical crystal and is used to adjust the light refractive index of the electro-optical crystal through the action of an electric field.

5. The optical filter with independently adjustable central wavelength and half-width at half maximum according to claim 1, characterized in that: The type of the electro-optical crystal is potassium dihydrogen phosphate or ammonium dihydrogen phosphate or lithium niobate or lithium tantalate.

6. The optical filter with independently adjustable central wavelength and half-width at half maximum according to claim 4, characterized in that: It also includes a shell and an adjustment panel, wherein the first input port, the second input port, the polarization light combiner, the electro-optical crystal, the polarization light splitter, the first output port, the second output port, and the electric field control device are all fixedly arranged inside the shell, and the adjustment panel is electrically connected to the electric field control device, and the adjustment panel is fixedly arranged on the outer surface of the shell.

7. The optical filter with independently adjustable central wavelength and half-width at half maximum according to claim 1, characterized in that: It also includes an optical wave splitter, an optical wave combiner, a first silicon optical modulator, a second silicon optical modulator, a first rotating plate, a second rotating plate, a third rotating plate, a first semiconductor optical amplifier, a second semiconductor optical amplifier, a first monitoring photodiode and a second monitoring photodiode; The first output end of the optical wave splitter is connected to the input end of the first silicon optical modulator, and the output end of the first silicon optical modulator is connected to the first input port; The second output end of the optical wave splitter is connected to the input end of the second silicon optical modulator, the output end of the second silicon optical modulator is connected to the input end of the first rotating plate, and the output end of the first rotating plate is connected to the second input port; The first output port is connected to the input end of the first semiconductor optical amplifier, and the output end of the first semiconductor optical amplifier is connected to the first input end of the optical wave combiner; The second output port is connected to the input end of the second rotating plate, the output end of the second rotating plate is connected to the input end of the second semiconductor optical amplifier, the output end of the second semiconductor optical amplifier is connected to the input end of the third rotating plate, and the output end of the third rotating plate is connected to the second input end of the optical wave combiner; The monitoring end of the first monitoring photodiode is connected to the output end of the first semiconductor optical amplifier, and the monitoring end of the second monitoring photodiode is connected to the output end of the third rotating plate.

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