阅读说明：本技术 一种分光监控反馈控制的rosa模块及控制方法 (ROSA module for light splitting monitoring feedback control and control method ) 是由 潘儒胜 李连城 周益平 郑波 孙鼎 魏志坚 张伟 过开甲 于 2021-01-18 设计创作，主要内容包括：本发明提供一种分光监控反馈控制的ROSA模块及控制方法,该模块包括：分光波导用于对输入的汇聚光按照预设分光比例进行分光,以主光路和分光路两路光进行输出；SOA芯片与分光波导耦合对接,输出增益光；监控PD用于对输入的分光路的光进行检测得到检测光生电流,并根据检测光生电流得到外部光的功率大小,控制器用于根据外部光的功率大小进行SOA芯片的增益电流和光放大倍数的自动调节。本发明通过硅基波导分光,在外部光进入到SOA的同时进入监控PD,检测出外部光输入功率,当光功率大于预设最大值时,及时反馈调整SOA增益电流,及时调整光放大倍数并减小增益噪声；规避大的光功率对SOA芯片的损坏,保护SOA芯片。(The invention provides a ROSA module of light splitting monitoring feedback control and a control method, wherein the ROSA module comprises: the light splitting waveguide is used for splitting input converged light according to a preset light splitting ratio and outputting the light in a main light path and a light splitting path; the SOA chip is coupled and butted with the light splitting waveguide to output gain light; the monitoring PD is used for detecting input light of the light splitting path to obtain detection photo-generated current and obtaining the power of external light according to the detection photo-generated current, and the controller is used for automatically adjusting the gain current and the light amplification factor of the SOA chip according to the power of the external light. According to the invention, through silicon-based waveguide light splitting, external light enters a monitoring PD while entering an SOA, external light input power is detected, when the light power is greater than a preset maximum value, SOA gain current is fed back and adjusted in time, the light amplification factor is adjusted in time, and gain noise is reduced; the damage of large optical power to the SOA chip is avoided, and the SOA chip is protected.)

1. A feedback-controlled ROSA module for split-beam monitoring, comprising:

the light splitting waveguide is used for splitting the input converged light according to a preset light splitting ratio and outputting the light in a main light path and a light splitting path;

the SOA chip is coupled and butted with the light splitting waveguide and outputs gain light;

the monitoring PD is used for detecting the input light of the light splitting path to obtain detection photo-generated current and obtaining the power of external light according to the detection photo-generated current;

and the controller is used for automatically adjusting the gain current and the optical amplification factor of the SOA chip according to the power of the external light.

2. The optical-splitting-monitoring-feedback-controlled ROSA module of claim 1, further comprising: the device comprises a collimating lens and a converging lens, wherein the collimating lens is used for refracting external light into parallel light beams, and the converging lens is used for converging the incident parallel light beams into one point;

the light splitting waveguide is provided with an input end, and the focal point of the converging lens is positioned at the input end of the light splitting waveguide.

3. The optical splitter supervisory feedback controlled ROSA module of claim 1, wherein said optical splitter waveguide has a first optical output port for outputting light from a main optical path and a second optical output port for outputting light from a splitter optical path.

4. The optical splitting monitoring feedback controlled ROSA module of claim 1, wherein a main optical path of said optical splitting waveguide is coupled and interfaced with an SOA chip by an index matching glue, and an optical splitting path of said optical splitting waveguide is interfaced with a monitoring PD.

5. The optical splitting monitoring feedback controlled ROSA module of claim 1, wherein said predetermined splitting ratio is:

a main light path: optical splitting path = N1: n2, wherein N1 and N2 are natural numbers, and N1 > N2.

6. The optical-splitting-monitoring-feedback-controlled ROSA module of claim 1, further comprising:

and the optical multiplexing component is used for demultiplexing the gain light to obtain at least one path of demultiplexing light.

7. The optical supervisory feedback controlled ROSA module of claim 6, wherein said optical multiplexing component includes:

the input end of the demultiplexing unit is connected with the SOA chip and is used for demultiplexing light with different wavelengths and outputting at least one path of demultiplexing split light, and one path of demultiplexing split light corresponds to one light splitting lens.

8. A spectral monitoring feedback controlled ROSA module according to claim 7, further comprising:

a light reflecting element for reflecting the demultiplexed light from the spectral lens;

and a photo-generated PD for receiving the reflected light of the light reflection element and generating an output photo-generated current.

9. A spectral monitoring feedback controlled ROSA module according to any of claims 1-8 and wherein said controller comprises:

the adjusting unit is used for adjusting the gain current of the SOA chip and adjusting the optical amplification factor of the SOA chip when the power of external light is larger than a preset maximum value;

and the protection unit is used for generating a closing signal when the power of the external light exceeds the bearing capacity of the SOA chip.

10. A spectral control method of a ROSA module based on spectral monitoring feedback control is characterized by comprising the following steps:

splitting the input converged light according to a preset splitting ratio, and outputting the split light by a main light path and a splitting light path;

the main light path is coupled and butted with the SOA chip and outputs gain light;

detecting light of the branch light path to obtain detection photo-generated current;

obtaining the power of external light according to the detected photo-generated current;

and automatically adjusting the gain current and the optical amplification factor of the SOA chip according to the power of external light.

Technical Field

The invention relates to the technical field of optical communication, in particular to a ROSA module for optical splitting monitoring feedback control and a control method.

Background

In the application of optical fiber communication transmission optical modules, the transmission rate requirement is higher and higher, and due to high-rate transmission, the link budget of the transmission distance is higher and higher under the influence of multiple factors such as optical fiber dispersion and loss. At the distance of 40KM or 80KM for transmission at the speed of 4X25G or above, the conventional APD ROSA can not meet the requirement of IEEE802.3.ba 100GBASE ER4 protocol in sensitivity index, and can only be used as ER4 LITE. In order to meet the standard index requirements of 40KM and ER4 transmission, a Receiver Optical Subassembly (ROSA) of SOA + PIN scheme is adopted. An Optical Subassembly (OSA) is a semiconductor Optical amplifier, and has an amplification effect on a weak Optical signal, so that a small Optical power after long-distance transmission loss is amplified, and a PIN photodiode receives a signal capable of being judged, thereby achieving the sensitivity required by specifications. A Semiconductor Optical Amplifier (SOA) is composed of an active region and a passive region, and the active region is a gain region. When an optical signal passes through the active region, it causes these electrons to lose energy in the form of photons and return to the ground state. The excited photons have the same wavelength as the optical signal, thereby amplifying the optical signal. As the injected current increases, the gain of the SOA increases, and when the current increases to a certain value, the gain saturates and does not increase further. Similarly, when a certain current is injected and saturation is not reached, the input optical power is increased, the output optical power is increased along with the gain coefficient, and when saturation is reached, the output optical power is not increased continuously.

Fig. 1 is a schematic diagram of a general SOA + PIN ROSA structure in the prior art, and as shown in fig. 1, the structure mainly includes: an optical port structure 101, a lens 102, an SOA chip 103, a semiconductor cooler TEC 104, a photodiode PD 105, an optical reflection element 106, a transimpedance amplifier TIA 107, a housing 108, and the like. External input light directly enters, the lens 102 converges the light on the optical waveguide of the SOA chip 103, the SOA chip 103 amplifies the optical power through input current, and then outputs the optical power to the PD chip 105, and photo-generated current is generated and enters the TIA 107.

However, the application of the existing SOA chip mainly amplifies a low-power optical signal, and if the input optical power is large and exceeds the maximum optical power which can be borne by the SOA chip, the SOA chip may be damaged, and meanwhile, when a large optical power is input, gain noise may be caused.

The above drawbacks are expected to be overcome by those skilled in the art.

Disclosure of Invention

Technical problem to be solved

In order to solve the above problems in the prior art, the present invention provides a ROSA module for optical splitting monitoring feedback control and a control method thereof, which solve the problem in the prior art that a SOA chip is damaged by a large optical power input.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

in one aspect, the present invention provides a feedback-controlled ROSA module for optical splitting monitoring, including:

the light splitting waveguide is used for splitting the input converged light according to a preset light splitting ratio and outputting the light in a main light path and a light splitting path;

the SOA chip is coupled and butted with the light splitting waveguide and outputs gain light;

the monitoring PD is used for detecting the input light of the light splitting path to obtain detection photo-generated current and obtaining the power of external light according to the detection photo-generated current;

and the controller is used for automatically adjusting the gain current and the optical amplification factor of the SOA chip according to the power of the external light.

In an exemplary embodiment of the present invention, further comprising: the device comprises a collimating lens and a converging lens, wherein the collimating lens is used for refracting external light into parallel light beams, and the converging lens is used for converging the incident parallel light beams into one point;

the light splitting waveguide is provided with an input end, and the focal point of the converging lens is positioned at the input end of the light splitting waveguide.

In an exemplary embodiment of the present invention, the optical splitter waveguide has a first light outlet port for outputting light of the main optical path and a second light outlet port for outputting light of the optical splitter path.

In an exemplary embodiment of the present invention, the main optical path of the optical splitting waveguide is coupled and butted with the SOA chip through an index matching adhesive, and the optical splitting path of the optical splitting waveguide is butted with the monitoring PD.

In an exemplary embodiment of the present invention, the preset splitting ratio is:

a main light path: optical splitting path = N1: n2, wherein N1 and N2 are natural numbers, and N1 > N2.

In an exemplary embodiment of the present invention, further comprising:

and the optical multiplexing component is used for demultiplexing the gain light to obtain at least one path of demultiplexing light.

In one exemplary embodiment of the present invention, the optical multiplexing assembly includes:

the input end of the demultiplexing unit is connected with the SOA chip and is used for demultiplexing light with different wavelengths and outputting at least one path of demultiplexing split light, and one path of demultiplexing split light corresponds to one light splitting lens.

In an exemplary embodiment of the present invention, further comprising:

a light reflecting element for reflecting the demultiplexed light from the spectral lens;

and a photo-generated PD for receiving the reflected light of the light reflection element and generating an output photo-generated current.

In one exemplary embodiment of the present invention, the controller includes:

the adjusting unit is used for adjusting the gain current of the SOA chip and adjusting the optical amplification factor of the SOA chip when the power of external light is larger than a preset maximum value;

and the protection unit is used for generating a closing signal when the power of the external light exceeds the bearing capacity of the SOA chip.

On the other hand, the invention also provides a spectral control method of the ROSA module based on spectral monitoring feedback control, which comprises the following steps:

splitting the input converged light according to a preset splitting ratio, and outputting the split light by a main light path and a splitting light path;

the main light path is coupled and butted with the SOA chip and outputs gain light;

detecting light of the branch light path to obtain detection photo-generated current;

obtaining the power of external light according to the detected photo-generated current;

and automatically adjusting the gain current and the optical amplification factor of the SOA chip according to the power of external light.

(III) advantageous effects

The ROSA module and the control method for the light-splitting monitoring feedback control provided by the embodiment of the invention have the beneficial effects that:

by means of silicon-based waveguide light splitting, external light can enter a monitoring PD simultaneously when entering an SOA, external light input power is detected, when the light power is larger than a preset maximum value, SOA gain current is fed back and adjusted in time, light amplification times are adjusted in time, and gain noise is reduced; or when the optical power is judged to be too high to exceed the SOA bearing capacity, timely closing measures can be taken, the damage of the high optical power to the SOA chip is effectively avoided, and the SOA chip is protected.

Drawings

FIG. 1 is a schematic diagram of a typical SOA + PIN ROSA structure in the prior art;

fig. 2 is a schematic diagram illustrating a ROSA module for optical splitter monitoring feedback control according to an embodiment of the present invention;

fig. 3 is a schematic cross-sectional view of an SOA + PIN ROSA structure provided in an embodiment of the present invention;

fig. 4 is a top view of an SOA + PIN ROSA structure provided in an embodiment of the present invention;

FIG. 5 is a schematic illustration of a silicon-based waveguide 304 in accordance with an embodiment of the present invention;

FIG. 6 is a functional block diagram of a ROSA in accordance with one embodiment of the present invention;

fig. 7 is a flowchart illustrating a method for controlling the split of a ROSA module based on feedback control of split monitoring according to another embodiment of the present invention.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the prior art, the Signal Strength in the ROSA module is output to an applied optical module MCU by a Received Signal Strength Indication (RSSI) of the TIA. The optical module controls the input current of the SOA chip according to the RSSI intensity, so that the APC function of monitoring, adjusting and feeding back is achieved.

However, for the application of multi-channel SOA + PIN, such as 4 × 25G SOA PIN ROSA, external input light is first four-way combined wave and enters an SOA chip through an optical port structure. After four paths of low-power signal light are simultaneously amplified by the SOA chip, the four paths of low-power signal light enter a built-in DEMUX optical element for wavelength division demultiplexing, four wavelengths of light are separated, the four wavelengths of light respectively enter the PD chip and are output by four paths of RSSI monitoring ports. The disadvantage is that the light power of four wavelengths is inconsistent, which causes the strength of each RSSI to be inconsistent, so that it is difficult to accurately control the input current of the SOA chip.

Aiming at the problems, the prior ROSA structure is improved, and external light enters the monitoring PD simultaneously when entering the SOA through the silicon-based waveguide light splitting, so that the external light power is detected.

Fig. 2 is a schematic diagram illustrating a component of an optical splitter monitoring feedback controlled ROSA module according to an embodiment of the present invention, and as shown in fig. 2, the SOA + PIN ROSA module 200 includes: an optical splitter waveguide 210, an SOA chip 220, a monitoring PD 230, and a controller 240.

The light splitting waveguide 210 is configured to split input converged light according to a preset light splitting ratio, and output the split light as two paths of light, namely a main light path and a light splitting path; the SOA chip 220 is coupled and butted with the optical splitter waveguide 210 to output gain light; the monitoring PD 230 is configured to detect light of the input optical splitter to obtain a detection photo-generated current, and obtain a power of external light according to the detection photo-generated current; the controller 240 is used for automatically adjusting the gain current and the optical amplification factor of the SOA chip according to the power of the external light.

Above-mentioned SOA + PIN ROSA module is through setting up beam splitting waveguide, SOA chip, control PD and watch-dog, and silica-based waveguide carries out the beam splitting, can enter into the control PD when external light enters into the SOA chip, detects out the power size of external light, can effectively avoid big optical power to the damage of SOA chip, protection SOA chip to reduce the gain noise. In addition, the magnitude of the external light power can be judged by monitoring the photo-generated current generated by the PD, and the photo-generated current is fed back to the controller to regulate the SOA input current and implement the control of the light amplification gain.

Fig. 3 is a schematic cross-sectional view of an SOA + PIN ROSA structure provided in an embodiment of the present invention, and fig. 4 is a top view of the SOA + PIN ROSA structure provided in an embodiment of the present invention, as shown in fig. 3 and fig. 4, the present invention provides a 4X25Gbps SOA + PIN ROSA with forward light splitting and PD detection functions, which can be applied to long-distance optical fiber transmission.

The following describes a specific structure of the SOA + PIN ROSA module with reference to fig. 3 and 4:

as shown in fig. 3 and 4, the SOA + PIN ROSA module mainly includes: the optical module comprises a front-end optical port structure 301, a collimating lens 302, a converging lens 303, a silicon-based waveguide 304, an SOA chip 305, a monitoring PD 306, a demultiplexing unit 307, a light splitting lens 308, an optical reflection element 309, a photo-generated PD 310, a TIA chip 311 and an external PAD 320 (figure 4). The controller is not shown in fig. 3 and 4, and the front-end optical port structure 301 is the same as that in the prior art, and is not described herein again.

In one exemplary embodiment of the present invention, the lens assembly includes: a collimator lens 302 and a condenser lens 303; wherein the collimating lens 302 is mounted on the front end optical port structure 301 for refracting external light emitted from a focal length into parallel light beams, and the converging lens 303 is used for converging the incident parallel light beams into a point, i.e. to a focal point of the lens.

In an exemplary embodiment of the present invention, the optical splitting waveguide has an optical splitting function, and for example, a silicon-based waveguide may be used. Fig. 5 is a schematic diagram of a silicon-based waveguide 304 according to an embodiment of the invention, and as shown in fig. 5, the silicon-based waveguide 304 has an optical input port P0, and the focal point of the converging lens is located at the optical input port of the optical splitter waveguide. The silicon-based waveguide 304 further has a first light-exiting port P1 and a second light-exiting port P2, the first light-exiting port P1 is used for outputting light of the main optical path, and the second light-exiting port P2 is used for outputting light of the branch optical path.

In an exemplary embodiment of the present invention, the waveguides of the two light-emitting ports of the silicon-based waveguide have a certain splitting ratio, that is, a preset splitting ratio, where the preset splitting ratio is:

a main light path: optical splitting path = N1: n2, wherein N1 and N2 are natural numbers, and N1 > N2.

Wherein the size of presetting the beam split proportion can be set for according to the concrete demand of product, and the beam split proportion of main light path is great, and the beam split proportion of beam split path is less, can set up to N1 for example: n2= 9: 1, the main light path is 9 times of the light splitting path.

In an exemplary embodiment of the present invention, the main optical path of the optical splitting waveguide is coupled and butted with the SOA chip through an index matching adhesive, and the optical splitting path of the optical splitting waveguide is butted with the monitoring PD. The refractive index matching glue is selected according to different optical materials to match the refractive index, and after light of a main light path enters the SOA chip, the SOA chip amplifies an incident light signal and outputs gain light under the power-on condition.

In an exemplary embodiment of the present invention, the SOA + PIN ROSA module further includes: and the optical multiplexing component is used for demultiplexing the gain light to obtain at least one path of demultiplexing light. In the embodiment of the present invention, the optical multiplexing component is disposed behind the SOA chip, and the gain light output by the SOA chip is demultiplexed, and the structure shown in this embodiment is 4 channels as an example. It should be noted that the structure provided by the present invention is not limited to 4 channels, and can be used in a one-channel to multi-channel SOA product.

In an exemplary embodiment of the present invention, the optical multiplexing component includes a demultiplexing unit 307 and at least one optical splitting lens 308, an input end of the demultiplexing unit is connected to the SOA chip, and is configured to split light with different wavelengths and output at least one path of demultiplexed light, where one path of demultiplexed light corresponds to one optical splitting lens. The light input into the SOA chip is a light source of multipath wave, and after the SOA chip amplifies the light, the SOA chip performs demultiplexing unit to separate out the light with different wavelengths and correspondingly output the light to the PDs of all channels. As shown in fig. 4, taking 4 paths as an example, the light output from the demultiplexing unit 307 passes through 4 beam splitting lenses 308 with different wavelengths, such as 1270nm, 1290nm, 1310nm and 1330 nm.

In an exemplary embodiment of the present invention, the SOA + PIN ROSA module further includes: a light reflecting element 309 and a light-generating PD 310, the light reflecting element 309 being for reflecting the demultiplexed light from the beam splitting lens 308; the photo-generated PD 310 is for receiving the reflected light of the light reflecting element 309 and generating an output photo-generated current.

As shown in fig. 3, 312, 313, 315, and 316 are carriers, and 314 is a TEC. In addition, the structure comprises a shell and a connecting PAD and the like, and the description is omitted.

Fig. 6 is a functional block diagram of an SOA + PIN ROSA according to an embodiment of the present invention, as shown in fig. 6, the ROSA includes functional PINs such as VCC, GND, VPD, ISOA, TEC, Itec, and Re, and the monitoring PD (i.e., MPD) 306 has a positive PIN (MPD +) and a negative PIN (MPD-), which are respectively connected to the SOA chip and the optical port structure, and a photo-generated current Impd generated by the MPD further includes a thermal sensing element, and is connected to the Re PIN.

In one exemplary embodiment of the present invention, a controller includes: the adjusting unit is used for adjusting the gain current of the SOA chip and adjusting the optical amplification factor of the SOA chip when the power of external light is larger than a preset maximum value; the protection unit is used for generating a closing signal when the power of external light exceeds the bearing capacity of the SOA chip. Therefore, when the optical power is larger than the preset maximum value, the SOA gain current is fed back and adjusted in time, the optical amplification factor can be adjusted in time, and the gain noise is reduced; or when the optical power is too high to exceed the bearing capacity of the SOA chip, timely closing measures can be taken, the damage of the high optical power to the SOA chip is effectively avoided, and the SOA chip is protected.

Based on the SOA + PIN ROSA structure, the working principle is as follows:

the optical path enters from an external optical adapter interface, is coupled to the silicon-based waveguide light inlet port through a lens, the silicon-based waveguide performs light splitting, the main optical path is coupled and butted with the SOA through appropriate refractive index matching glue, the loss and reflection of optical coupling are reduced, and the light splitting path is directly butted with the monitoring PD. On one hand, after light of the main optical path enters the SOA, the SOA amplifies an incident light signal under the condition of being electrified, outputs gain light, enters a demultiplexing unit (namely, DEMUX) for demultiplexing and splitting, enters the PD after splitting, generates a photo-generated current signal, and outputs a converted signal after the photo-generated current signal enters the TIA. On the other hand, the light of the light splitting path goes to the monitoring PD, and photo-generated current is generated and transmitted to the external control through the lead wire. The magnitude of the external light power can be judged by monitoring the photo-generated current generated by the PD, the photo-generated current is fed back to the controller, the SOA input current is regulated, and the control on the light amplification gain is implemented. And finally, calculating the light power entering the SOA chip according to the light splitting ratio and the detection photo-generated current obtained by monitoring the PD detection.

It should be noted that, because the SOA + PIN ROSA module is used as a transmission link light detection, when a transmission link fails, that is, if a communication interruption occurs in the transmission link, whether light is incident or not can be detected through the silicon-based waveguide light splitting, so that whether the ROSA module is damaged or not has light source input is judged, whether a link problem or a device problem is identified, and the use is convenient.

It should be noted that the invention can solve the disadvantage that the input optical power is judged by the RSSI in the general scheme, i.e. the multi-channel RSSI values are inconsistent, the regulation procedure is complex, and the control is not accurate. The embodiment of the invention can determine the size of external input light by directly detecting the photo-generated current of the monitoring PD and combining the photo-generated current with the silicon-based waveguide to obtain the light splitting ratio.

In summary, in the ROSA module with the optical splitting monitoring feedback control provided in the embodiment of the present invention, by providing the lens assembly, the optical splitting waveguide, the SOA chip, and the monitoring PD, external light is split by the silicon-based waveguide after being incident, and the silicon-based waveguide is aligned with the SOA chip, so that light in a main optical path enters the SOA chip, and light in the optical splitting path enters the monitoring PD at the same time, the power of the external light is detected, and therefore, the damage of the SOA chip by a large optical power can be effectively avoided, the SOA chip is protected, and gain noise is reduced. In addition, the magnitude of the external light power can be judged by monitoring the photo-generated current generated by the PD, and the photo-generated current is fed back to the controller to regulate the SOA input current and implement the control of the light amplification gain. When the optical power is larger than a preset maximum value, the SOA gain current is fed back and adjusted in time, the optical amplification factor is adjusted in time, and the gain noise is reduced; or when the optical power is judged to be too high to exceed the SOA bearing capacity, timely closing measures can be taken, the damage of the high optical power to the SOA chip is effectively avoided, and the SOA chip is protected. In addition, if a communication interruption occurs in the transmission link, whether light is incident or not can be detected through the silicon-based waveguide light splitting, so that whether ROSA is damaged or whether no light source is input is judged, and whether the ROSA is in a link problem or a device problem is identified.

Fig. 7 is a flowchart illustrating a step of a method for controlling a spectral power of a ROSA module based on spectral monitoring feedback control according to another embodiment of the present invention, as shown in fig. 7, which specifically includes the following steps:

step S1, splitting the input convergent light according to a preset splitting ratio, and outputting the light by a main light path and a splitting light path;

step S2, coupling and butting the main light path and the SOA chip to output gain light;

step S3, detecting the light of the branch light path to obtain a detection photo-generated current;

step S4, obtaining the power of external light according to the detected photo-generated current;

and step S5, automatically adjusting the gain current and the optical amplification factor of the SOA chip according to the power of the external light.

Before step S1, the external light transmitted through the optical fiber needs to be received by the front-end optical port structure, and is collimated by the collimating lens and converged by the converging lens.

Based on the structure of the SOA + PIN ROSA module, the method can detect the input power of external light by splitting light through the silicon-based waveguide and simultaneously entering the monitoring PD when the external light enters the SOA. The damage of the high optical power to the SOA chip can be effectively avoided, and the SOA chip is protected. By means of silicon-based waveguide light splitting, large input light can be split, overlarge light entering the SOA is reduced, and hidden danger of increasing gain noise is avoided.

In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium; either as communication within the two elements or as an interactive relationship of the two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, a first feature may be "on" or "under" a second feature, and the first and second features may be in direct contact, or the first and second features may be in indirect contact via an intermediate. Also, a first feature "on," "above," and "over" a second feature may be directly or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lower level than the second feature.

In the description herein, the description of the terms "one embodiment," "some embodiments," "an embodiment," "an example," "a specific example" or "some examples" or the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are illustrative and not restrictive, and that those skilled in the art may make changes, modifications, substitutions and alterations to the above embodiments without departing from the scope of the present invention.