阅读说明：本技术 一种级联式可调硅基布拉格光栅色散补偿器 (Cascade type adjustable silicon-based Bragg grating dispersion compensator ) 是由 戴道锌 刘姝君 于 2021-01-19 设计创作，主要内容包括：本发明公开了一种级联式可调硅基布拉格光栅色散补偿器。多级光开关间经直波导和布拉格光栅色散补偿器串联,第一级光开关输入端连接输入端直波导,最后一级光开关输出端连接输出端直波导；每级布拉格光栅色散补偿器中,补偿器输入波导输入端和光开关输出端连接,补偿器输入波导输出端连接啁啾布拉格光栅输入端,补偿器输出波导输入端连接啁啾布拉格光栅输出端,补偿器输出波导输出端和光开关输入端连接,啁啾布拉格光栅上有加热电极。本发明通过级联布拉格光栅色散补偿器和集成加热电极精确调节和控制色散补偿值,以实现对色散值大范围精确补偿,具有集成度高、可调范围广、精度高等优点。(The invention discloses a cascade adjustable silicon-based Bragg grating dispersion compensator. The multistage optical switches are connected in series with the Bragg grating dispersion compensator through the straight waveguide, the input end of the first stage optical switch is connected with the straight waveguide at the input end, and the output end of the last stage optical switch is connected with the straight waveguide at the output end; in each stage of Bragg grating dispersion compensator, the input end of the compensator input waveguide is connected with the output end of the optical switch, the output end of the compensator input waveguide is connected with the input end of the chirped Bragg grating, the input end of the compensator output waveguide is connected with the output end of the chirped Bragg grating, the output end of the compensator output waveguide is connected with the input end of the optical switch, and the chirped Bragg grating is provided with a heating electrode. The invention realizes the large-range precise compensation of the dispersion value by precisely adjusting and controlling the dispersion compensation value through the cascade Bragg grating dispersion compensator and the integrated heating electrode, and has the advantages of high integration level, wide adjustable range, high precision and the like.)

1. A cascade type adjustable silicon-based Bragg grating dispersion compensator is characterized in that: the optical fiber switch comprises an input end straight waveguide (1), a multi-stage optical switch (2), a multi-stage Bragg grating dispersion compensator, straight waveguides (5) at all stages and an output end straight waveguide (8), wherein the multi-stage optical switch (2) is connected in series with the Bragg grating dispersion compensator through the straight waveguides (5), the input end straight waveguide (1) is connected with the input end of the first-stage optical switch (2), and the output end straight waveguide (8) is connected with the output end of the last-stage optical switch (2).

2. The cascaded tunable silicon-based bragg grating dispersion compensator of claim 1, wherein: one output end of the previous-stage optical switch (2) is connected with one input end of the next-stage optical switch (2) through a straight waveguide (5), and the other output end of the previous-stage optical switch (2) is connected with the other input end of the next-stage optical switch (2) through a Bragg grating dispersion compensator.

3. A cascaded tunable silicon-based bragg grating dispersion compensator according to claim 1 or 2, wherein: each stage of Bragg grating dispersion compensator mainly comprises a compensator input waveguide (3), a chirped Bragg grating (6), a heating electrode (7) and a compensator output waveguide (4); the input end of the compensator input waveguide (3) is connected with the output end of the previous stage optical switch (2), the output end of the compensator input waveguide (3) is connected with the input end of the chirped Bragg grating (6), the input end of the compensator output waveguide (4) is connected with the output end of the chirped Bragg grating (6), the output end of the compensator output waveguide (4) is connected with the input end of the next stage optical switch (2), and the chirped Bragg grating (6) is covered with the heating electrode (7).

4. The cascaded tunable silicon-based Bragg grating dispersion compensator of claim 3, wherein: input end straight waveguide (1) input optical signal, optical signal passes through optical switch (2) when every optical switch (2) the selection and connects next level Bragg grating dispersion compensator or connect next level straight waveguide (5), each level of optical signal gets into in the Bragg grating dispersion compensator, be through compensator input waveguide (3) input chirp Bragg grating (6), the light of different wavelength takes place to reflect and then change the optical distance and compensate in the different positions in Bragg grating (6), get into next level optical switch (2) through compensator output waveguide (4) after the compensation.

5. The cascaded tunable silicon-based Bragg grating dispersion compensator of claim 3, wherein: the compensator input waveguide (3) and the compensator output waveguide (4) are positioned on the same side of the chirped Bragg grating (6).

6. The cascaded tunable silicon-based Bragg grating dispersion compensator of claim 3, wherein: the chirped Bragg grating (6) is of a trapezoidal structure with a larger size at one end and a smaller size at the other end, the length of the Bragg grating is multiplied by adjusting the height of the trapezoidal structure, and the chirped Bragg grating is connected with the compensator input waveguide (3) and the compensator output waveguide (4) to multiply the dispersion compensation value.

7. The cascaded tunable silicon-based Bragg grating dispersion compensator of claim 3, wherein: the chirped Bragg grating (6) is of a trapezoidal structure with one end being large in size and the other end being small in size, and the direction of the large end or the small end of the trapezoidal structure is adjusted to be connected with the compensator input waveguide (3) and the compensator output waveguide (4) so as to adjust the positive and negative of dispersion compensation.

8. The cascaded tunable silicon-based bragg grating dispersion compensator of claim 1, wherein: the Bragg grating dispersion compensators are all integrated with heating electrodes (7) above the chirped Bragg gratings (6), the heating temperature is controlled by controlling the applied voltage on the heating electrodes (7), and then the dispersion compensation value and the bandwidth range of the Bragg grating dispersion compensators are accurately adjusted, and further the total dispersion compensation within the same bandwidth range is accurately adjusted.

9. The cascaded tunable silicon-based bragg grating dispersion compensator of claim 1, wherein: the input end straight waveguide (1), each stage of optical switch (2), the compensator input waveguide (3), the chirped Bragg grating (6), the compensator output waveguide (4), each stage of straight waveguide (5) and the output end straight waveguide (8) are all arranged on the substrate silicon and are manufactured by adopting monolithic integration.

10. The cascaded tunable silicon-based bragg grating dispersion compensator of claim 1, wherein: the core layer materials adopted by the input end straight waveguide (1), the compensator input waveguide (3), the chirped Bragg grating (6), the compensator output waveguide (4), each level of straight waveguides (5) and the output end straight waveguide (8) are all silicon.

Technical Field

The invention relates to a dispersion compensator, in particular to a cascade type adjustable silicon-based Bragg grating dispersion compensator.

Background

In an optical communication system, an optical signal is generally accompanied by chromatic dispersion after being transmitted for a long distance, so that the optical signal is subjected to pulse broadening and deformation, further crosstalk is generated, the system error rate is increased, the transmission rate and the transmission bandwidth are reduced, and the transmission distance is sharply reduced. The dispersion compensation device can be used for accurately compensating dispersion to greatly improve the quality of optical signals and ensure that the transmission efficiency and the transmission distance are not greatly influenced by the dispersion. In a device structure for dispersion compensation, a Bragg grating is often selected as a dispersion compensation device due to the advantages of easy connection of a waveguide, insensitivity to polarization and the like, and a chirped Bragg grating has different equivalent refractive indexes at different positions, can reflect different wavelengths in optical signals at different positions corresponding to different Bragg wavelengths, and can generate a time delay difference value among different wavelengths to compensate dispersion, so that the chirped Bragg grating has excellent properties as a dispersion compensation device in an optical communication system.

Meanwhile, with the development of silicon-based integrated photonic technology, the integrated device compatible with the CMOS process is widely researched and applied. The silicon material has strong light constraint capability, can integrate a large number of optical devices on a single chip, and realizes an on-chip integrated optical interconnection system with low energy consumption, small size and low cost. The existing silicon-based dispersion compensation device usually adopts a single chirped Bragg grating to carry out quantitative dispersion compensation on a fixed wavelength range, and the wavelength of the Bragg grating can be adjusted only through a single heating electrode, so that the adjustable range is small. However, the dispersion generated in an actual optical communication system generally varies with various environmental factors, and the conventional static dispersion compensation device has a small adjustable range and low precision, can only perform rough compensation, and cannot meet the requirement of large-range adjustable dispersion compensation of the optical communication system, so that a dispersion compensation technology capable of performing precise and large-range compensation values along with the system requirement is urgently needed.

Disclosure of Invention

Aiming at the problems in the background art, the invention aims to provide a cascaded adjustable silicon-based Bragg grating dispersion compensation device, thereby realizing large-range and high-precision dispersion value compensation, and having important application value due to a high-integration device structure.

The invention realizes the precise compensation of the dispersion value in a large range by precisely adjusting and controlling the dispersion compensation value through the cascade Bragg grating dispersion compensator and the integrated heating electrode, and has the advantages of high integration level, wide adjustable range, high precision and the like.

The technical scheme adopted by the invention is as follows:

the invention comprises an input end straight waveguide, a multi-stage optical switch, a multi-stage Bragg grating dispersion compensator, all stages of straight waveguides and output end straight waveguides, wherein the multi-stage optical switches are connected in series through the straight waveguides and the Bragg grating dispersion compensator, the input end of the first stage optical switch is connected with the input end straight waveguide, and the output end of the last stage optical switch is connected with the output end straight waveguide.

One output end of the upper-stage optical switch is connected with one input end of the lower-stage optical switch through the straight waveguide, and the other output end of the upper-stage optical switch is connected with the other input end of the lower-stage optical switch through the Bragg grating dispersion compensator.

Each stage of Bragg grating dispersion compensator mainly comprises a compensator input waveguide, a chirped Bragg grating, a heating electrode and a compensator output waveguide; the input end of the compensator input waveguide is connected with the output end of the upper stage optical switch, the output end of the compensator input waveguide is connected with the input end of the chirped Bragg grating, the input end of the compensator output waveguide is connected with the output end of the chirped Bragg grating, the output end of the compensator output waveguide is connected with the input end of the lower stage optical switch, and the chirped Bragg grating is covered with the heating electrode.

The input end of the straight waveguide inputs optical signals, the optical signals are selectively connected with a next stage of Bragg grating dispersion compensator or connected with a next stage of straight waveguide through the optical switch when passing through each optical switch, each stage of optical signals enter the Bragg grating dispersion compensator and are input into the chirped Bragg grating through the compensator input waveguide, light with different wavelengths is reflected at different positions in the Bragg grating so as to change the optical path for compensation, and the light with different wavelengths enters the next stage of optical switch through the compensator output waveguide after compensation.

The Bragg grating dispersion compensators at each stage correspond to different Bragg wavelengths at different positions through the chirped Bragg grating, and the reflected light signals generate time delay difference to realize the compensation of dispersion, wherein the chirped Bragg grating with doubled dispersion value can be a positive dispersion compensation Bragg grating and a negative dispersion compensation Bragg grating. Different stages of bragg-grating dispersion compensators have the same bragg wavelength bandwidth range. The number of cascades is increased to increase the total dispersion compensation value.

The compensator input waveguide and the compensator output waveguide are positioned on the same side of the chirped Bragg grating.

The chirped Bragg grating is of a trapezoidal structure with a larger size at one end and a smaller size at the other end, the length of the Bragg grating is multiplied by adjusting the height of the trapezoidal structure, and the chirped Bragg grating is connected with the input waveguide of the compensator and the output waveguide of the compensator so as to multiply the dispersion compensation value.

The chirped Bragg grating is of a trapezoidal structure with one end being larger in size and the other end being smaller in size, and the direction of the large end or the small end of the trapezoidal structure is adjusted to be connected with the input waveguide of the compensator and the output waveguide of the compensator so as to adjust the positive and negative of dispersion compensation.

The Bragg grating dispersion compensators are integrated with heating electrodes above the chirped Bragg gratings, the heating temperature is controlled by controlling the applied voltage on the heating electrodes, and then the dispersion compensation value and the bandwidth range of each Bragg grating dispersion compensator are accurately adjusted, and further the total dispersion compensation within the same bandwidth range is accurately adjusted.

The input end straight waveguide, each level of optical switch, the compensator input waveguide, the chirped Bragg grating, the compensator output waveguide, each level of straight waveguide and the output end straight waveguide are all arranged on the substrate silicon and are manufactured by adopting single-chip integration.

The core layer materials adopted by the input end straight waveguide, the compensator input waveguide, the chirped Bragg grating, the compensator output waveguide, each level of straight waveguide and the output end straight waveguide are all silicon.

The existing large number of single chirped Bragg gratings perform quantitative dispersion compensation in a fixed wavelength range, and the static dispersion compensation can only perform rough compensation. If the heating electrode is adopted to adjust the corresponding wavelength position of the single Bragg grating, the adjustable range is also very small. The cascade design of the invention greatly increases the compensation value of dispersion compensation, and can select the required dispersion compensation value through the optical switch to realize the adjustment as required within the compensation dispersion value range.

The Bragg grating dispersion compensator realizes dispersion compensation through the chirped Bragg grating, and the chirped Bragg grating can realize gradual change of corresponding equivalent refractive index in a mode of changing the period or the waveguide width so as to realize that different Bragg wavelength values are corresponding to different positions and optical signals with different wavelengths are reflected to form time delay difference among different wavelengths and realize the compensation of dispersion.

The Bragg grating dispersion compensator integrates a heating electrode above each stage of Bragg grating, and utilizes the heating electrode to finely adjust the compensation range of the grating, so as to accurately control the dispersion compensation range and the compensation value according to requirements. The voltage of each level of heating electrode can be adjusted through the integrated electric control system, so that accurate feedback of each level of dispersion compensation value is realized, and the same compensation bandwidth between different levels can be ensured by adjusting the voltage of the heating electrode.

The invention has the beneficial effects that:

the invention has a cascade structure, so that the range of the dispersion compensation value is greatly increased, the positive and negative of the dispersion compensation value can be selected, and the range of the required dispersion compensation value can be selected through the optical switch.

The invention precisely adjusts the dispersion compensation range and the compensation value by integrating the heating electrode, controls the voltage of the heating electrode to finely adjust the dispersion compensation range and the compensation value of each stage of grating, and ensures that the dispersion compensation bandwidths are the same among different stages. The voltage of the integrated heating electrode can be adjusted by an electric control system.

The invention has the advantages of simple and convenient process, high integration level and the like by silicon substrate integration, and has the excellent performances of large band-pass range, accurate compensation, low loss and the like.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of a cascaded tunable silicon-based Bragg grating dispersion compensator according to the present invention.

Figure 2 is a schematic diagram of an embodiment of the chirped bragg grating of the present invention.

FIG. 3 is a schematic structural diagram of an embodiment of a cascaded tunable silicon-based Bragg grating dispersion compensator according to the present invention.

In the figure: 1. an input end straight waveguide, 2, an optical switch, 3, a compensator input waveguide, 4, a compensator output waveguide, 5, a straight waveguide, 6, a chirped Bragg grating, 6a-6c, a chirped Bragg grating, 7, a heating electrode, 7a-c, a heating electrode, 8 and an output end straight waveguide.

Detailed Description

The invention is further illustrated by the following figures and examples.

As shown in fig. 1, the dispersion compensator implemented specifically includes an input end straight waveguide 1, a multi-stage optical switch 2, a multi-stage bragg grating dispersion compensator, each stage of straight waveguides 5 and an output end straight waveguide 8, the multi-stage optical switches 2 are connected in series through the straight waveguides 5 and the bragg grating dispersion compensator, the input end of the first stage optical switch 2 is connected to the input end straight waveguide 1, and the output end of the last stage optical switch 2 is connected to the output end straight waveguide 8; one output end of the upper-stage optical switch 2 is connected with one input end of the lower-stage optical switch 2 through a straight waveguide 5, and the other output end of the upper-stage optical switch 2 is connected with the other input end of the lower-stage optical switch 2 through a Bragg grating dispersion compensator.

As shown in fig. 1, each stage of bragg grating dispersion compensator mainly consists of a compensator input waveguide 3, a chirped bragg grating 6, a heating electrode 7 and a compensator output waveguide 4; the input end of the compensator input waveguide 3 is connected with the output end of the upper stage optical switch 2, the output end of the compensator input waveguide 3 is connected with the input end of the chirped Bragg grating 6, the input end of the compensator output waveguide 4 is connected with the output end of the chirped Bragg grating 6, the output end of the compensator output waveguide 4 is connected with the input end of the lower stage optical switch 2, and the chirped Bragg grating 6 is covered with a heating electrode 7; the cascade of each level is input through the input end straight waveguide 1, the upper level optical switch 2 is connected with the lower level optical switch 2 through the compensator input waveguide 3 and each level of straight waveguide 5 in each level of Bragg grating dispersion compensator, the compensator output waveguide 4 and each level of straight waveguide 5 in each level of Bragg grating dispersion compensator are connected with the lower level optical switch 2, and the cascade of each level is output through the output waveguide 8.

The input end straight waveguide 1 inputs optical signals, the optical signals are selectively connected with a next-stage Bragg grating dispersion compensator or a next-stage straight waveguide 5 through the optical switch 2 when passing through each optical switch 2, and a dispersion value compensation range is selected according to actual requirements, specifically, the optical signals output by the input end straight waveguide 1, each stage of compensator output waveguide 4 or each stage of straight waveguide 5 enter the Bragg grating dispersion compensator or the next-stage straight waveguide 5 through the optical switch 2; each level of optical signal enters the Bragg grating dispersion compensator, the chirped Bragg grating 6 is input through the compensator input waveguide 3, light with different wavelengths is reflected at different positions in the Bragg grating 6 so as to change the optical path for compensation, the compensated optical signal enters the next-level optical switch 2 through the compensator output waveguide 4, whether the next-level dispersion compensation value is needed or not is selected through the next-level optical switch 2, and the input and output signal separation mode can be a circulator, a multimode interference coupler MMI, mode regulation and control and the like.

Each stage of Bragg grating dispersion compensator compensates dispersion through the chirped grating, and meanwhile, an integrated heating electrode is used for acting on the grating to perform dispersion compensation adjustment.

The compensator input waveguide 3 and the compensator output waveguide 4 are located on the same side of the chirped bragg grating 6, as shown in fig. 2, the chirped bragg grating 6 is in a trapezoidal structure with one end having a larger size and the other end having a smaller size, and the large end or the small end of the trapezoidal structure is adjusted to face and connect the compensator input waveguide 3 and the compensator output waveguide 4 so as to adjust the positive and negative of dispersion compensation. When the small end of the trapezoid structure faces and connects the compensator input waveguide 3 and the compensator output waveguide 4, the dispersion compensation is positive; negative compensation of dispersion compensation occurs when the large end of the ladder structure is directed towards and connects the compensator input waveguide 3 and the compensator output waveguide 4.

As shown in fig. 3, the height of the trapezoid structure is adjusted to increase the length of the bragg grating by multiple times, and the input waveguide 3 of the compensator and the output waveguide 4 of the compensator are connected to increase the dispersion compensation value by multiple times. When the height of the ladder structure is doubled and the compensator input waveguide 3 and the compensator output waveguide 4 are connected, the dispersion compensation is doubled at this time; when the height of the ladder structure is increased by two times and the compensator input waveguide 3 and the compensator output waveguide 4 are connected, the dispersion compensation is increased by two times at this time;

the Bragg grating dispersion compensators are integrated with the heating electrodes 7 above the chirped Bragg gratings 6, the heating temperature is controlled by controlling the applied voltage on the heating electrodes 7, and then the dispersion compensation value and the bandwidth range of each Bragg grating dispersion compensator are accurately adjusted, and further the total dispersion compensation in the same bandwidth is accurately adjusted.

Each stage of Bragg grating dispersion compensator realizes dispersion compensation effect through the chirped Bragg grating 6, realizes gradual change of corresponding equivalent refractive index by using the chirped Bragg grating through a mode of changing the period or the waveguide width, compensates dispersion values corresponding to different Bragg wavelengths at different positions, reflects optical signals with different wavelengths at different positions to form time delay difference among different wavelengths, and realizes the compensation of dispersion.

As shown in fig. 2, a positive dispersion compensation bragg grating and a negative dispersion compensation bragg grating may be cascaded, where the bragg grating of each stage corresponds to a certain dispersion compensation range, and the bragg grating dispersion compensators of different stages have different dispersion compensation ranges, and in the specific implementation process, the total dispersion compensation value range may be increased by increasing the number of cascades, and the range of the required dispersion compensation value may be selected by an optical switch. And a heating electrode is integrated above each stage of Bragg grating, the compensation range of the Bragg grating is finely adjusted by utilizing the heating electrode, and the dispersion is accurately compensated according to the requirement. The voltage of each level of heating electrode is regulated through the integrated electric control system, accurate feedback of each compensation wave band is achieved, synchronization of compensation values among compensation ranges of each level is achieved, and overlapping and gap influences among corresponding optical wave bands of different levels are removed through regulation.

Specific example 1 of the present invention is given below:

in the embodiment, a silicon-based optical waveguide based on a silicon-on-insulator (SOI) material is selected, a core layer of the silicon-based optical waveguide is made of a silicon material, the thickness of the core layer is 220nm, the refractive index of the core layer is 3.4744, the working waveband is a communication waveband, and the Bragg grating micro-regulation and control are realized by covering a heating electrode on an upper layer. Selecting a single-mode waveguide with the waveguide width of 500nm, selecting each level of symmetrical chirped Bragg grating with the period of 285nm, and gradually changing the width of the Bragg grating to form an equivalent refractive index, wherein the reflection waveband is a communication waveband near 1550 nm.

Firstly, determining the dispersion value of an optical signal to be compensated in the dispersion value adjusting range within the bandwidth provided by the cascade type adjustable silicon-based Bragg grating dispersion compensator, determining the positions of all stages required for compensation in a cascade type structure, selecting an input compensator input waveguide 3 at the front end of each stage required by the optical switch, inputting the input compensator into the Bragg grating dispersion compensator, or else, entering a straight waveguide 5. The compensator input waveguide 3 and the compensator output waveguide 4 are connected to the chirped bragg grating 6 by a circulator.

An optical signal is input from an input end straight waveguide 1, is selectively input into a Bragg grating dispersion compensator input waveguide 3 or a straight waveguide 5 through an optical switch 2, and directly selects the compensation of the next stage through a next stage switch 2 if the optical signal enters the straight waveguide. The optical signal separates the incoming signal from the outgoing signal at the output of the bragg dispersion compensator by a circulator. The outgoing optical signal after dispersion compensation is input from the compensator output waveguide 4 to the next-stage optical switch 2 to select the next-stage compensation. The optical signal is output through the output waveguide 8 after being cascaded at each stage to selectively compensate chromatic dispersion. The whole cascade device utilizes the heating electrode integrated on the chirped Bragg grating to slightly adjust the compensation range, and accurately compensates the dispersion value and the range according to the transmission condition of the optical signal. The voltage of each level of heating electrode is regulated through the integrated electric control system, so that accurate feedback of compensation bandwidth and compensation values among different levels is realized, and synchronization of different levels of compensation wave bands is ensured.

Specific example 2 of the present invention is given below:

the example is a multiple type dispersion compensation grating array, a silicon-based optical waveguide based on a silicon-on-insulator (SOI) material is selected, a core layer of the multiple type dispersion compensation grating array is made of a silicon material, the thickness of the core layer is 220nm, the refractive index of the multiple type dispersion compensation grating array is 3.4744, the working waveband is a communication waveband near 1550nm, and the Bragg grating micro-regulation and control are realized in a mode that an upper layer covers a heating electrode. Selecting a multimode waveguide with the waveguide width of 1000nm, selecting each level of asymmetric chirped Bragg grating with the period of 300nm and the length gradually doubled, and gradually changing the equivalent refractive index through the gradual change of the Bragg grating width to form a communication waveband with the reflection waveband near 1550 nm.

Firstly, determining the dispersion value of an optical signal to be compensated in the dispersion value adjusting range within the bandwidth provided by the cascade type adjustable silicon-based Bragg grating dispersion compensator, determining the positions of all stages required for compensation in a cascade type structure, selecting an input compensator input waveguide 3 at the front end of each stage required by the optical switch, inputting the input compensator into the Bragg grating dispersion compensator, or else, entering a straight waveguide 5. The compensator input waveguide 3 and the compensator output waveguide 4 are connected to the chirped bragg grating 6 by a circulator.

As shown in fig. 3, an optical signal is input from an input end straight waveguide 1, and is selectively input to a bragg grating dispersion compensator input waveguide 3 or a straight waveguide 5 via an optical switch 2, and when the optical signal enters the straight waveguide, the next stage of compensation is directly selected via a next stage switch 2. The optical signal to be compensated passes through the asymmetric Bragg dispersion compensator in a TE0 mode and then outputs a TE1 mode at the output end, and the optical signal is output through the mode-downloading waveguide to separate an incident signal and an emergent signal. The outgoing optical signal after dispersion compensation is input from the compensator output waveguide 4 to the next-stage optical switch 2 to select the next-stage compensation. The optical signal is output through the output waveguide 8 after being cascaded at each stage to selectively compensate chromatic dispersion. The whole cascade device doubles the compensation value of the chirped Bragg grating with doubled length in the same wave band, slightly adjusts the compensation value and the bandwidth range by the heating electrode integrated on the chirped Bragg grating, and realizes the dispersion precise compensation in the same wave band range according to the transmission condition of optical signals. The voltage of each level of heating electrode is adjusted through the integrated electric control system, accurate feedback of the compensation waveband dispersion value is achieved, and the corresponding optical wavebands of different levels are the same through adjustment.

The above-described embodiments are intended to illustrate rather than to limit the invention, and any modifications and variations of the present invention are within the spirit of the invention and the scope of the appended claims.