Laser and preparation method thereof

Abstract

According to the laser and the preparation method thereof provided by the invention, the laser comprises the packaging cavity, and the packaging cavity is internally provided with the gain chip, the wavelength selection assembly and the reflector. Each gain chip comprises a top layer, a bottom layer and a light-emitting layer. Each light-emitting layer comprises a first active area, a passive grating area and a second active area. The first active region emits a light beam of a wide wavelength range. The end face of the passive grating area can serve as a first resonance end face of the laser. The reflector serves as a second resonant end face of the laser and forms a resonant cavity with the first resonant end face. The wavelength selection assembly selects the light with the specific wavelength from the light beams with the wide wavelength range, the light with the specific wavelength oscillates back and forth in the resonant cavity to obtain the gain to form the laser, and the second active area further performs gain amplification on the laser, so that the output light power of the laser is improved. On-chip integration of the first active area and the second active area is realized through the passive grating area, so that the size of a packaging cavity is reduced, and the laser is miniaturized.

Description

Technical Field

[0001] The present disclosure relates to the field of optical communication technology, and in particular to a laser and a method for preparing the same. Background Art

[0002] Due to the increase in communication capacity requirements, coherent optical modules use modulation methods such as quadrature amplitude modulation (QAM) to maximize the capacity of optical fibers. However, the insertion loss of these modulation methods is relatively large, so tunable lasers are required to output higher optical power. Summary of the invention

[0003] The present disclosure provides a laser and a method for manufacturing the same, which integrates a gain chip with a semiconductor optical amplifier chip to output higher optical power while reducing the packaging volume.

[0004] The laser provided in the present disclosure includes a packaging cavity, and the packaging cavity is provided with:

[0005] Gain chips, including:

[0006] The top layer includes a first electrode region and a second electrode region, wherein a first electrical isolation groove is formed between the first electrode region and the second electrode region;

[0007] The bottom layer includes a third electrode region, and the third electrode region is electrically connected to the first electrode region and the second electrode region respectively to output carriers;

[0008] The light-emitting layer is located between the top layer and the bottom layer, and includes a light-emitting area, and the light-emitting area includes the following connected in sequence:

[0009] a first active region, located within a downwardly projected region of the first electrode region, for receiving carriers and for emitting a light beam in a wide wavelength range according to the injected carriers;

[0010] A passive grating region, located in the downward projection region of the first electrical isolation groove, includes a grating region and a waveguide region, and is used to provide a first resonant end face for the laser;

[0011] A second active region is located within a downwardly projected region of the second electrode region to receive carriers;

[0012] A wavelength selection component is disposed on one side of the first active region and is used to select light of a specific wavelength from the light beam emitted from the first active region;

[0013] A reflector, disposed on one side of the wavelength selection component, for providing a second resonant end face for the laser, so that the light of a specific wavelength selected by the wavelength selection component oscillates between the first resonant end face and the second resonant end face to form laser light, and transmits the laser light to the second active region;

[0014] The second active region is used to amplify the laser light according to the injected carriers.

[0015] In the laser and its preparation method provided by the present disclosure, the laser includes a packaging cavity, and a gain chip, a wavelength selection component and a reflector are respectively arranged inside the packaging cavity. Among them, the gain chip includes a top layer, a bottom layer and a light-emitting layer located between the top layer and the bottom layer, and the light-emitting layer includes a light-emitting area, and the light-emitting area includes a first active area, a passive grating area and a second active area connected in sequence. The top layer includes a first electrode area and a second electrode area, respectively, and a first electrical isolation groove is formed between the first electrode area and the second electrode area; the bottom layer includes a third electrode area, and the third electrode area is electrically connected to the first electrode area and the second electrode area, respectively, so as to inject carriers into the first active area and the second active area, respectively. Among them, the first active area is located in the downward projection area of ​​the first electrode area, and emits a light beam with a wide wavelength range according to the injected carriers. The passive grating area includes a grating, which acts as a reflector and can be used as the first resonant end face of the laser resonant cavity to reflect light of a specific wavelength. The wavelength reflected by the passive grating region is related to the effective refractive index of the passive grating region, and the effective refractive index is related to the current size. In order to ensure the stability of the effective refractive index of the passive grating region, the injection of carriers into the passive grating region should be avoided. Therefore, the passive grating region is located in the downward projection area of ​​the first electrical isolation groove. The setting of the first electrical isolation groove can prevent the flow of carriers into the passive grating region, play an electrical isolation role, and thus avoid the injection of carriers into the passive grating region. The second active region is located in the downward projection area of ​​the second electrode region. In the present disclosure, the reflector serves as the second resonant end face of the laser resonant cavity, and the first resonant end face and the second resonant end face constitute the resonant cavity of the laser. In the present disclosure, a wavelength selection component is used to select a light of a specific wavelength from the light beam with a wide wavelength range output by the first active region. The light of the specific wavelength is reflected and oscillated back and forth in the resonant cavity, and a positive gain is obtained to form a laser. The formed laser is transmitted along the passive grating region to the second active region. The second active region further amplifies the gain of the laser according to the injected carriers, thereby increasing the output optical power of the laser. In the laser provided by the present disclosure, the second active region is integrated into the gain chip through the passive grating region, and the second active region can amplify the laser formed after oscillation, thereby increasing the output optical power of the laser; at the same time, the first active region and the second active region are connected through the passive grating region, which can reduce problems such as interface reflection compared to using a lens or an optical fiber, thereby ensuring the output optical power of the laser. The present disclosure realizes on-chip integration of the first active region and the second active region through the passive grating region, the first active region is used as a gain region, and the second active region is used as an optical amplifier to increase the output optical power of the laser. The end face of the passive grating region provides an effective reflection end face for the laser, and there is no need to separately set a semiconductor optical amplifier outside the gain chip, thereby reducing the volume of the packaging cavity, which is conducive to the miniaturization of the laser. At the same time, it is also conducive to the discrete tuning of the laser specific and output optical power to adapt to different usage environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0017] Figure 1 A partial architecture diagram of an optical communication system provided according to some embodiments of the present disclosure;

[0018] Figure 2 A partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0019] Figure 3 A structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0020] Figure 4 An exploded view of an optical module provided according to some embodiments of the present disclosure;

[0021] Figure 5 An internal structure diagram of an optical module provided according to some embodiments of the present disclosure;

[0022] Figure 6 An internal structure diagram of a tunable laser provided according to some embodiments of the present disclosure;

[0023] Figure 7 A structural diagram of a gain chip provided according to some embodiments of the present disclosure;

[0024] Figure 8 is a cross-sectional view of a gain chip provided according to some embodiments of the present disclosure;

[0025] Fig. 9 A schematic diagram of optical transmission of a tunable laser provided according to some embodiments of the present disclosure;

[0026] Fig.10 A schematic diagram of a preparation process of a gain chip provided according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0027] In optical communication technology, in order to establish information transmission between information processing devices, it is necessary to load information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When optical signals are transmitted in information transmission equipment, the loss of optical power can be reduced, so high-speed, long-distance, and low-cost information transmission can be achieved. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment usually includes optical network terminals (Optical Network Unit, ONU), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment usually includes optical fibers and optical waveguides.

[0028] The optical module can realize the mutual conversion between optical signals and electrical signals between information processing equipment and information transmission equipment. For example, at least one of the optical signal input end or the optical signal output end of the optical module is connected to an optical fiber, and at least one of the electrical signal input end or the electrical signal output end of the optical module is connected to an optical network terminal; the first optical signal from the optical fiber is transmitted to the optical module, and the optical module converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the optical network terminal; the second electrical signal from the optical network terminal is transmitted to the optical module, and the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber. Since multiple information processing devices can transmit information through electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, and all information processing devices do not need to be directly connected to the optical module. Here, the information processing device directly connected to the optical module is called the upper computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module can be called an optical port, and the electrical signal input end or the electrical signal output end of the optical module can be called an electrical port.

[0029] Figure 1 FIG. 1 is a partial architecture diagram of an optical communication system provided according to some embodiments of the present disclosure. Figure 1 As shown, the optical communication system mainly includes a remote information processing device 1000 , a local information processing device 2000 , a host computer 100 , an optical module 200 , an optical fiber 101 and a network cable 103 .

[0030] One end of the optical fiber 101 extends toward the remote information processing device 1000, and the other end of the optical fiber 101 is connected to the optical module 200 through the optical port of the optical module 200. The optical signal can be totally reflected in the optical fiber 101, and the propagation of the optical signal in the total reflection direction can almost maintain the original optical power. The optical signal undergoes multiple total reflections in the optical fiber 101 to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or to transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance, low-power loss information transmission.

[0031] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 are detachably connected or fixedly connected to the optical module 200. The host computer 100 is configured to provide data signals to the optical module 200, receive data signals from the optical module 200, or monitor or control the working state of the optical module 200.

[0032] The host computer 100 includes a substantially rectangular housing and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to connect to the optical module 200 so that the host computer 100 and the optical module 200 establish a unidirectional or bidirectional electrical signal connection.

[0033] The host computer 100 also includes an external electrical interface, which can be connected to an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104, and the network cable interface 104 is configured to access the network cable 103 so that the host computer 100 establishes a unidirectional or bidirectional electrical signal connection with the network cable 103. One end of the network cable 103 is connected to the local information processing device 2000, and the other end of the network cable 103 is connected to the host computer 100, so as to establish an electrical signal connection between the local information processing device 2000 and the host computer 100 through the network cable 103. For example, the third electrical signal sent by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103, and the host computer 100 generates a second electrical signal according to the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200, and the optical module 200 converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber 101, and the second optical signal is transmitted to the remote information processing device 1000 in the optical fiber 101. For example, the first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101, and the first optical signal from the optical fiber 101 is transmitted to the optical module 200, and the optical module 200 converts the first optical signal into a first electrical signal, and the optical module 200 transmits the first electrical signal to the host computer 100, and the host computer 100 generates a fourth electrical signal according to the first electrical signal, and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that the optical module is a tool for realizing the mutual conversion between optical signals and electrical signals. During the conversion process between the optical signals and electrical signals, the information does not change, but the encoding and decoding methods of the information can change.

[0034] In addition to the optical network terminal, the host computer 100 also includes an optical line terminal (OLT), an optical network device (ONT), or a data center server.

[0035] Figure 2 1 is a partial structural diagram of a host computer provided according to some embodiments of the present disclosure. In order to clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 Only the structure of the host computer 100 related to the optical module 200 is shown. Figure 2 As shown, the host computer 100 further includes a PCB circuit board 105 disposed in the housing, a cage 106 disposed on the surface of the PCB circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access the electrical port of the optical module 200; the heat sink 107 has a protruding structure such as fins to increase the heat dissipation area.

[0036] The optical module 200 is inserted into the cage 106 of the host computer 100, and the cage 106 fixes the optical module 200. The heat generated by the optical module 200 is transferred to the cage 106 and then diffused through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 establishes a bidirectional electrical signal connection with the host computer 100. In addition, the optical port of the optical module 200 is connected to the optical fiber 101, so that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101.

[0037] Figure 3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure, Figure 4 FIG. 1 is an exploded view of an optical module provided according to some embodiments of the present disclosure. Figure 3 and Figure 4 As shown, the optical module 200 includes a shell, a circuit board 300 disposed in the shell, a tunable laser 900 , and a coherent optical component 1100 .

[0038] The housing comprises an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing having two openings 204 and 205 . The outer contour of the housing is generally a square body.

[0039] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and arranged perpendicular to the bottom plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0040] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and vertically arranged with the bottom plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and vertically arranged with the cover plate 2011, and the two upper side plates are combined with the two lower side plates 2022 to realize that the upper shell 201 covers the lower shell 202.

[0041] The direction of the line connecting the two openings 204 and 205 may be consistent with the length direction of the optical module 200, or may be inconsistent with the length direction of the optical module 200. For example, the opening 204 is located at the end of the optical module 200 ( Figure 3 The opening 205 is also located at the end of the optical module 200 ( Figure 3 Alternatively, the opening 204 is located at the end of the optical module 200, and the opening 205 is located at the side of the optical module 200. The opening 204 is an electrical port, and the gold finger 301 of the circuit board 300 extends from the opening 204 and is inserted into the electrical connector of the host computer 100; the opening 205 is an optical port, which is configured to access the external optical fiber 101, so that the optical fiber 101 is connected to the tunable laser 900 and the coherent optical component 1100 in the optical module 200.

[0042] The upper housing 201 and the lower housing 202 are combined to facilitate the installation of the circuit board 300, the tunable laser 900, the coherent optical component 1100, etc. into the above housing, and the upper housing 201 and the lower housing 202 can encapsulate and protect the above components. In addition, when assembling the circuit board 300, the tunable laser 900, the coherent optical component 1100, etc., it is convenient to deploy the positioning components, heat dissipation components, and electromagnetic shielding components of these components, which is conducive to the automated production.

[0043] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials to facilitate electromagnetic shielding and heat dissipation.

[0044] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside its housing. The unlocking component 600 is configured to achieve a fixed connection between the optical module 200 and the host computer, or to release the fixed connection between the optical module 200 and the host computer.

[0045] For example, the unlocking component 600 is located on the outside of the two lower side plates 2022 of the lower housing 202, and includes a snap-fit ​​component that matches the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the snap-fit ​​component of the unlocking component 600 fixes the optical module 200 in the cage 106; when the unlocking component 600 is pulled, the snap-fit ​​component of the unlocking component 600 moves accordingly, thereby changing the connection relationship between the snap-fit ​​component and the host computer, so as to release the fixation of the optical module 200 and the host computer, so that the optical module 200 can be pulled out of the cage 106.

[0046] The circuit board 300 includes circuit traces, electronic components and chips, etc. The electronic components and chips are connected according to the circuit design through the circuit traces to realize the functions of power supply, electrical signal transmission and grounding. The electronic components may include capacitors, resistors, transistors, metal-oxide-semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), etc. The chips may include microcontroller units (Microcontroller Unit, MCU), laser driver chips, transimpedance amplifiers (Transimpedance Amplifier, TIA), limiting amplifiers (Limiting amplifier), clock and data recovery chips (Clock and Data Recovery, CDR), power management chips, digital signal processing (Digital Signal Processing, DSP) chips.

[0047] The circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also realize the load-bearing function. For example, the rigid circuit board can stably carry the above-mentioned electronic components and chips; the rigid circuit board can also be inserted into the electrical connector in the cage 106 of the host computer 100.

[0048] The circuit board 300 also includes a gold finger 301 formed on the end surface thereof. The gold finger 301 is composed of a plurality of independent pins. The circuit board 300 is inserted into the cage 106, and the gold finger 301 is connected to the electrical connector in the cage 106. The gold finger 301 can be provided on only one side of the circuit board 300 (e.g. Figure 4The upper surface shown in the figure) can also be set on the upper and lower surfaces of the circuit board 300 to provide more pins, so as to adapt to occasions where the number of pins is large. The gold finger 301 is configured to establish an electrical connection with the host computer to achieve power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, data signal transmission, etc. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement rigid circuit boards.

[0049] Figure 5 FIG. 1 is an internal structure diagram of an optical module provided according to some embodiments of the present disclosure. Figure 5 As shown, in some embodiments, a tunable laser 900 and a coherent optical component 1100 are respectively provided on the surface of the circuit board 300. The coherent optical component 1100 includes an optical modulation chip inside, and the optical modulation chip is used to modulate and demodulate the optical signal. Exemplarily, the optical modulation chip is a silicon photonic chip or a thin-film lithium niobate chip.

[0050] The optical modulation chip itself does not have a light source. The tunable laser 900 is used as an external light source of the optical modulation chip. The tunable laser 900 emits light from the side, and the light it emits enters the optical modulation chip, thereby modulating the optical signal through the modulator built into the optical modulation chip. The external optical signal enters the optical modulation chip and is then coherently demodulated with the local oscillator light to achieve demodulation of the optical signal.

[0051] Figure 6 FIG. 1 is an internal structure diagram of a tunable laser provided according to some embodiments of the present disclosure. Figure 6 As shown, in some embodiments, the tunable laser 900 includes a package cavity, and the interior of the package cavity includes a gain chip 910, a lens 920, a wavelength selection component, a phase shifter 940, and a reflector 960. Exemplarily, the wavelength selection component includes a first filter and a second filter, such as a first etalon 930 and a second etalon 950.

[0052] In some embodiments, carriers are injected into the gain chip 910, and the gain chip 910 emits light of a wide wavelength range according to the carriers, and then specific currents are respectively input into the first etalon 930 and the second etalon 950 to heat the first etalon 930 and the second etalon 950 to a specific temperature, so that light of a specific wavelength can be screened out from the wide spectrum light to achieve wavelength selection. By providing currents of different magnitudes to the wavelength selection component to perform temperature tuning on the wavelength selection component, wavelength tuning is achieved.

[0053] The light emitted by the gain chip 910 is divergent light, so the divergent light beam emitted by the gain chip 910 is collimated into a parallel light beam through the lens 920, and then enters the first etalon 930 in the form of parallel light. Through the combination of the first etalon 930 and the second etalon 950, the wavelength that can pass through both of them is screened out. Specifically, by heating the first etalon 930 and the second etalon 950 respectively, the required wavelength (target wavelength) can be selected through the vernier effect of the two.

[0054] The first etalon 930 and the second etalon 950 are arranged at an interval to form a vernier etalon. The FSR (Freespectral range) of the two etalons is different. Based on the vernier principle, the light waves in the common passable wavelength band of the first etalon 930 and the second etalon 950 can be screened out, that is, when a wavelength in the transmission spectra of the two etalons coincides (i.e., is aligned), the light of the specific wavelength can be selected.

[0055] In some embodiments, by heating the first standard tool 930 and the second standard tool 950 to different temperatures, the refractive index of the two standards changes accordingly, and then the optical path of the two standards changes, and the cavity length of the resonant cavity changes accordingly, and the wavelength selected by the two standards changes, thereby achieving wavelength tuning.

[0056] In some embodiments, the resonant cavity of the tunable laser 900 is relatively long, and there are many cavity modes that may oscillate. The filter transmission spectrum allows only one of the cavity modes to have a lower loss and form a laser oscillation output. Since the cavity mode is easily drifted due to the influence of temperature, stress, etc., and the output wavelength is related to the cavity mode, which causes the output wavelength to drift, it is necessary to lock the specific wavelength selected by the wavelength selection component. In some embodiments, by changing the temperature of the phase shifter 940 to change the refractive index of the phase shifter 940, the optical length of the phase shifter 940 is changed, and then the cavity length of the resonant cavity is changed to lock the cavity length of the resonant cavity, and correspondingly lock the cavity mode of the resonant cavity, and then lock the wavelength.

[0057] In some embodiments, one end face of the gain chip 910 serves as the first resonant end face of the resonant cavity of the tunable laser 900, and the reflector 960 serves as the second resonant end face of the resonant cavity. The first resonant end face and the second resonant end face constitute a resonant cavity. The resonant cavity has a laser mode wavelength (i.e., resonant wavelength) supported by it. The laser mode can be a longitudinal mode or a transverse mode. The laser mode wavelength is related to the length of the resonant cavity. When the current wavelength is the laser mode wavelength supported by the resonant cavity, the light of the current wavelength can oscillate in the resonant cavity to obtain a positive net gain, and finally form a laser output. When the current wavelength is not the wavelength supported by the resonant cavity, the light cannot oscillate in the resonant cavity and eventually disappears in the resonant cavity. By tuning the temperature of the wavelength selection component and tuning the length of the resonant cavity to the resonant cavity length corresponding to the light of a specific wavelength (i.e., the target wavelength), the light of the specific wavelength selected by the wavelength selection component reflects and oscillates back and forth in the resonant cavity. When the gain is equal to the loss, the spontaneous emission is converted into stimulated emission, thereby forming a laser output.

[0058] In some embodiments of the present disclosure, in order to increase the laser output optical power, a semiconductor optical amplifier is further provided inside the packaging cavity. In some embodiments, an optical fiber adapter is provided on the outer wall of the packaging cavity, and the optical fiber adapter is close to the reflector 960. The semiconductor optical amplifier is provided between the optical fiber adapter and the reflector 960, and the oscillated laser is amplified by the semiconductor optical amplifier to increase the laser output optical power. When a semiconductor optical amplifier is used to further amplify the optical power, a lens is added between the discrete gain chip and the semiconductor optical amplifier, or the discrete devices are coupled with optical fiber to obtain a higher power output. However, due to the problems of interface reflection and large loss in lens or optical fiber coupling, the optical power is reduced.

[0059] In some embodiments of the present disclosure, in order to increase the laser output optical power and avoid setting the gain chip and the semiconductor optical amplifier separately, the gain chip and the semiconductor optical amplifier can be integrated. Since one of the end faces of the gain chip is the first resonant end face, a reflective film should be plated on the end face of the gain chip. The semiconductor optical amplifier is a one-way optical device, so the two end faces of the gain chip should be plated with high-transmittance films respectively and the waveguide should be bent and tilted to prevent the end face feedback light from affecting the laser mode selection.

[0060] Figure 7 A structural diagram of a gain chip provided according to some embodiments of the present disclosure; Figure 8 FIG. 1 is a cross-sectional view of a gain chip provided according to some embodiments of the present disclosure. Figure 7 and Figure 8As shown, in some embodiments of the present disclosure, the gain chip 910 includes, from top to bottom, a top layer 911, a contact layer 912, an upper limiting layer 913, a light emitting layer 914, a lower limiting layer 915, and a bottom layer 916. Among them, the top layer 911 is mainly a protective layer, which is a passivation layer, and plays the role of anti-oxidation, waterproofing, etc., so as to protect the gain chip 910.

[0061] An upper electrode is formed on the surface of the top layer 911, and a lower electrode is formed on the surface of the bottom layer 916. The upper and lower electrodes are respectively connected to the positive and negative electrodes of the power supply, thereby forming an electrical circuit to output carriers. The contact layer 912 is an ohmic contact layer, and its material is InGaAs. The upper limiting layer 913 and the lower limiting layer 915 are respectively located on both sides of the light-emitting layer 914, and are mainly used to provide a heterojunction to better regulate and limit the recombination area of ​​the carriers, and to limit the light within the light-emitting layer 914.

[0062] In some embodiments, the light emitting layer 914 includes a light emitting area 914a, and the light emitting area 914a includes a first active area 9141, a passive grating area 9142, and a second active area 9143 connected in sequence. Exemplarily, the first active area 9141 and the second active area 9143 need to be powered, and the passive grating area 9142 is not powered. The passive grating area 9142 includes a grating area 9144 and a waveguide area 9145.

[0063] In some embodiments, the first active region 9141 and the second active region 9143 both adopt a multi-quantum well structure, thereby improving the ability of the active region to collect carriers and increasing the ability of radiation recombination.

[0064] In some embodiments, the passive grating region 9142 can achieve a flat reflection spectrum and act as a reflector, which can serve as the first resonant end face of the laser resonant cavity to reflect light of a specific wavelength. The wavelength range reflected by the passive grating region is affected by the refractive index of the passive grating region, and the fluctuation of the carrier concentration in the region will affect the refractive index. In order to ensure the stability of the effective refractive index of the passive grating region, the injection of carriers into the passive grating region should be avoided. Therefore, in the present disclosure, the surface of the top layer 911 is recessed downward to form a first electrical isolation groove 917. At this time, the first electrical isolation groove 917 splits the upper electrode into a first electrode region 9111 and a second electrode region 9112, that is, the first electrical isolation groove 917 is located between the first electrode region 9111 and the second electrode region 9112. At the same time, the first active area 9141 is arranged in the downward projection area of ​​the first electrode area 9111, the second active area 9143 is arranged in the downward projection area of ​​the second electrode area 9112, and the passive grating area 9142 is located in the downward projection area of ​​the first electrical isolation groove 917. The arrangement of the first electrical isolation groove 917 can ensure that more carriers are effectively injected into the first active area 9141 and the second active area 9143, thereby ensuring the carrier concentration of the first active area 9141 and the second active area 9143. At the same time, the arrangement of the first electrical isolation groove 917 can prevent the injection of carriers into the passive grating area 9142, play an electrical isolation role, thereby preventing the injection of carriers into the passive grating area 9142, and ensuring the stability of the effective refractive index of the passive grating area 9142.

[0065] In the present disclosure, the bottom layer 916 includes a third electrode region, the third electrode region and the first electrode region 9111 serve as a negative electrode and a positive electrode, respectively, and the first active region 9141 is located below the first electrode region 9111, thereby effectively injecting carriers into the first active region 9141. Similarly, the second active region 9143 is located below the second electrode region 9112, thereby effectively injecting carriers into the second active region 9143.

[0066] In some embodiments, the conductivity of the contact layer 912 is relatively high. In order to prevent carriers from being transmitted to the passive grating region 9142 through the contact layer 912, the first electrical isolation groove 917 is extended downward to the contact layer 912, and the contact layer 912 is divided into a first contact region 9121 and a second contact region 9122. Exemplarily, the first contact region 9121 is located below the first electrode region 9111, and the second contact region 9122 is located below the second electrode region 9112. Further, the first electrical isolation groove 917 may continue to extend downward to the upper limiting layer 913.

[0067] In some embodiments, the first active region 9141 is located directly below the first electrode region 9111, and the second active region 9143 is located directly below the second electrode region 9112. In order to prevent carriers from flowing to both sides of the first active region 9141 and the second active region 9143, thereby reducing the concentration of carriers injected into the first active region 9141 and the second active region 9143, a second electrical isolation groove 918 and a third electrical isolation groove 919 are respectively formed on both sides of the first electrical isolation groove 917. Exemplarily, on one side of the first electrical isolation groove 917, the second electrical isolation groove 918 is hollowed out from the top layer 911 downwards, and the second electrical isolation groove 918 is located on one side of the light-emitting region 914a; on the other side of the first electrical isolation groove 917, the third electrical isolation groove 919 is hollowed out from the top layer 911 downwards, and the third electrical isolation groove 919 is located on the other side of the light-emitting region 914a.

[0068] The lengths of the second electrical isolation groove 918 and the third electrical isolation groove 919 are consistent with the length of the gain chip 910. The lengths of the second electrical isolation groove 918 and the third electrical isolation groove 919 respectively cover the first active area 9141, the passive grating area 9142 and the second active area 9143 laterally. The depths of the two can extend downward to the upper confinement layer 913 to fully confine the output carriers to the first active area 9141 and the second active area 9143, avoid the transmission of carriers to the two sides of the first active area 9141 and the second active area 9143, and further ensure the concentration of carriers transmitted to the first active area 9141 and the second active area 9143.

[0069] In some embodiments, the first active region 9141 emits spontaneous emission light with a wide wavelength range according to the carriers injected from the first electrode region 9111, and by tuning the temperature of the wavelength selection component, light of a specific wavelength is selected from the light beam emitted by the first active region 9141. The selected light of a specific wavelength has reduced loss in the resonant cavity formed by the passive grating region 9142 and the reflector 960, and reflects and oscillates back and forth in the resonant cavity. When the gain is equal to the loss, the spontaneous emission light emitted by the first active region 9141 begins to be converted into stimulated emission, forming laser output. The formed laser is transmitted to the second active region 9143 through the passive grating region 9142, and the second active region 9143 amplifies the optical power of the laser according to the injected carriers, thereby increasing the laser output optical power.

[0070] In some embodiments, an optical fiber adapter 970 is provided on the outer wall of the packaging cavity, and the optical fiber adapter 970 is located on a side close to the gain chip 910. The laser amplified by the second active region 9143 is transmitted to the optical fiber adapter 970, and then transmitted to the outside of the tunable laser 900 through the optical fiber adapter 970 to achieve laser emission.

[0071] In some embodiments of the present disclosure, the first electrode region 9111, the first contact region 9121, the upper limiting layer region corresponding to the first contact region 9121, the first active region 9141, the lower limiting layer region corresponding to the first active region 9141 and the corresponding third electrode region are arranged in sequence from top to bottom to constitute a gain region 910a.

[0072] The second electrode region 9112, the second contact region 9122, the upper limiting layer region corresponding to the second contact region 9122, the second active region 9143, the lower limiting layer region corresponding to the second active region 9143 and the corresponding third electrode region are arranged in sequence from top to bottom to constitute the light amplification region 910c.

[0073] The grating region 910b is located between the gain region 910a and the optical amplifier region 910c. In the present disclosure, the optical amplifier region 910c is equivalent to an optical amplifier, which is integrated into the gain chip 910 and connected to the gain region 910a and the optical amplifier region 910c through the grating region 910b, thereby achieving optical power amplification.

[0074] In the present disclosure, the grating region 910b can achieve a flat reflection spectrum in the C band, so the grating region 910b serves as the first resonant end face of the resonant cavity, and the reflector 960 serves as the second resonant end face of the resonant cavity. The selected light of a specific wavelength reflects and oscillates back and forth between the grating region 910b and the reflector 960, and reflects and oscillates back and forth in the resonant cavity. When the gain is equal to the loss, the spontaneous emission light emitted by the first active region 9141 begins to be converted into stimulated emission, forming laser output.

[0075] In the present disclosure, the gain region 910a and the optical amplification region 910c are electrically isolated by the first electrical isolation groove 917. Therefore, the gain region 910a and the optical amplification region 910c can be electrically tuned separately. For example, different currents can be provided to the gain region 910a and the optical amplification region 910c separately.

[0076] In some embodiments of the present disclosure, the first high-transmittance film 910d and the second high-transmittance film 910e are respectively plated at both ends of the gain chip 910. The first high-transmittance film 910d is disposed adjacent to the first active area 9141, which is beneficial to increase the transmittance of light incident on and out of the first active area 9141; the second high-transmittance film 910e is disposed adjacent to the second active area 9143, which is beneficial to increase the transmittance of light incident on and out of the second active area 9143.

[0077] In the present disclosure, due to the presence of the grating region 910b, the integration of the optical amplifier into the gain chip is realized. The gain region 910a is connected to the optical amplifier region 910c through the grating region 910b. At the same time, the grating region 910b provides a first resonant end face, so that light of a specific wavelength is reflected and oscillated back and forth between the grating region 910b and the reflector 960, and a positive gain layer is obtained, thereby forming a laser. At the same time, the two ends of the gain chip 910 are respectively coated with a first high-transmittance film 910d and a second high-transmittance film 910e, so as to ensure the normal operation of the optical amplifier.

[0078] In the laser provided by the present disclosure, the second active region 9143 is integrated into the gain chip 910 through the passive grating region 9142, and the second active region 9143 can amplify the laser formed after oscillation, thereby increasing the output optical power of the laser. At the same time, the first active region 9141 and the second active region 9143 are connected through the passive grating region 9142, which can reduce problems such as interface reflection compared to using a lens or optical fiber, thereby ensuring the output optical power of the laser. The present disclosure integrates the second active region 9143 inside the gain chip 910, and the second active region 9143 can increase the output optical power of the laser as an optical amplifier, thereby eliminating the need to separately set up a semiconductor optical amplifier outside the gain chip, thereby reducing the volume of the packaging cavity, which is conducive to the miniaturization of the laser.

[0079] The present invention realizes on-chip integration of the first active region 9141 and the second active region 9143 through the passive grating region 9142. The first active region 9141 is used as a gain region, and the second active region 9143 is used as an optical amplifier to increase the output optical power of the laser. The end face of the passive grating region 9142 provides an effective reflection end face for the laser, and thus there is no need to separately set a semiconductor optical amplifier outside the gain chip, thereby reducing the volume of the packaging cavity, which is conducive to miniaturization of the laser. At the same time, it is also conducive to discrete tuning of the laser specific and output optical power to adapt to different use environments.

[0080] In some embodiments of the present disclosure, the passive grating region 9142 includes a grating region 9144 and a waveguide region 9145. The light of a wide range of wavelengths emitted by the first active region 9141 is transmitted along the waveguide region 9145. In some embodiments, the light spot emitted by the first active region 9141 is relatively large and will cover the grating region 9144 and the waveguide region 9145 for transmission. Exemplarily, the grating region 9144 reflects the wavelength that meets the Bragg condition.

[0081] In the present disclosure, the tunable laser is expected to achieve stable power output within a wide wavelength range. If the end reflectivity difference is large, it will have a greater impact on the threshold, power and SMSR of the laser at different wavelengths, and will increase the difficulty of adjusting the module output power and the power consumption difference. To this end, the grating area 9144 adopts a passive apodized chirped grating. By transforming the grating structure, a wide-spectrum reflection with uniform reflectivity within the wavelength range can be achieved, thereby achieving a stable output of optical power within the band. The grating period of the apodized chirped grating varies gradually with the spatial position, and the feedback intensity varies with the apodization function along the light propagation direction. The grating intensity variation is regulated by a series of m grating periods as a group, and n high refractive index regions are retained in the m grating periods. The reflectivity of the grating and the reflection spectrum width can be adjusted by adjusting the grating structure and the grating refractive index difference. Exemplarily, by adjusting the values ​​of m and n to adjust the grating structure, and then adjusting the reflectivity and reflection spectrum width of the grating, wide-spectrum reflection with uniform reflectivity within the wavelength range is achieved, thereby achieving stable output of optical power within the band.

[0082] In some embodiments of the present disclosure, the coherent optical communication system uses the phase of light to increase the communication capacity, thus requiring the tunable laser 900 to have a lower phase noise. From 10G to 400G communication systems, there are higher requirements for indicators such as the line width and relative intensity noise of the laser, and the line width is reduced from 5MHz to 300kHz accordingly. For the 16-QAM modulation format, the line width of the laser is required to be less than 100kHz, and the relative intensity noise is reduced to -145dB / Hz.

[0083] In some implementations, the passive grating region 9142 is undoped to reduce losses. However, undoped semiconductor materials will still introduce some impurities during the growth process. These impurities will form shallow donor or acceptor energy levels in the bandgap. The semiconductor material absorbs photons and generates carriers. The carriers are in a dynamic equilibrium state. The fluctuation of carrier concentration causes the change of refractive index, which leads to the broadening of the laser spectrum, thereby affecting the line width, relative intensity noise, etc. of the laser.

[0084] In some embodiments, the grating region 9144 and the waveguide region 9145 in the passive grating region 9142 are doped with Fe during the growth process. The doped Fe can serve as a donor energy level to compensate for the shallow donor impurity energy level, thereby reducing the free carrier concentration in the material and forming an insulating layer, thereby reducing the free carrier absorption loss in the material, thereby increasing the light output power of the device and reducing the line width, relative intensity noise, etc. of the laser.

[0085] Fig. 9 FIG. 1 is a schematic diagram of optical transmission of a tunable laser according to some embodiments of the present disclosure. Fig. 9As shown, in some embodiments of the present disclosure, the optical fiber adapter 970 is located at one side of the optical amplification region 910c, and the following are arranged in sequence from the side where the optical fiber adapter 970 is located to the other side: the optical fiber adapter 970, the optical amplification region 910c, the grating region 910b, the gain region 910, the wavelength selection component and the reflector 960. Exemplarily, the wavelength selection component includes a first etalon 930 and a second etalon 950.

[0086] The grating region 910 is the first resonant end face of the resonant cavity, and the reflector 960 is the second resonant end face of the resonant cavity. The gain region 910 emits a light beam with a wide range of wavelengths according to the injected carriers; by tuning the temperature of the wavelength selection component, light of a specific wavelength is selected from the light beam with a wide range of wavelengths. The light of the specific wavelength is the target wavelength, and the light of the specific wavelength is reflected and oscillated back and forth in the resonant cavity to obtain positive gain, thereby forming a laser. The laser formed after oscillation is transmitted to the optical fiber adapter 970 through the grating region 910b, and then transmitted to the outside of the tunable laser 900 through the optical fiber adapter 970, thereby providing a light source for the coherent optical component.

[0087] In some embodiments, a second high-transmittance film 910e is plated on the side of the optical amplifier region 910 facing the optical fiber adapter 970, and a first high-transmittance film 910d is plated on the side of the gain region 910a facing the first etalon 930. The first high-transmittance film 910d is disposed adjacent to the first active region 9141 in the gain region 910a, which is beneficial to increasing the transmittance of light incident on and out of the first active region 9141; the second high-transmittance film 910e is disposed adjacent to the second active region 9143 in the optical amplifier region 910, which is beneficial to increasing the transmittance of light incident on and out of the second active region 9143.

[0088] In some embodiments of the present disclosure, the two sides of the grating region 910b are connected to the gain region 910a and the optical amplifier region 910c respectively by a butt-jointed growth process, thereby integrating the optical amplifier into the gain chip in order to obtain a gain chip that can output higher optical power.

[0089] The embodiment of the present disclosure provides a method for preparing a laser, which is applied to the above-mentioned laser. A gain chip is packaged in the laser, so the method for preparing the laser includes a method for preparing the gain chip.

[0090] Fig.10 FIG. 1 is a schematic diagram of a process for preparing a gain chip according to some embodiments of the present disclosure. Fig.10 As shown, in some embodiments of the present disclosure, the preparation process of the gain chip 110 includes:

[0091] S110: growing a buffer layer c, a multi-quantum well structure layer b and a cap layer a in sequence from bottom to top.

[0092] In some embodiments, the multi-quantum well structure layer b is wrapped between the buffer layer c and the cap layer a. The multi-quantum well structure layer b is used for the subsequent preparation of the first active region 9141 and the second active region 9143. The first active region 9141 and the second active region 9143 both adopt a multi-quantum well structure, thereby improving the ability of the active region to collect carriers and increasing the ability of radiation recombination. As the number of quantum wells increases, the number of activated substances increases, and the optical gain gradually increases, thereby increasing the output optical power.

[0093] S120: Etching longitudinally downward along the local surface of the cap layer to the surface of the buffer layer to form a vacant area A.

[0094] In some embodiments, one side of the empty region A corresponds to the optical amplification region 910c, the other side of the empty region A corresponds to the gain region 910a, and the empty region A corresponds to the grating region 910b. Exemplarily, the empty region A is excavated for the subsequent growth of the passive grating region 9142.

[0095] S130: growing a passive structure on the surface of the empty area A, the passive structure comprising two layers of passive waveguides, making a grating area 9144 on the surface of the upper passive waveguide; then growing a grating covering layer on the surface of the grating area 9144 to make the grating covering layer flush with the surface of the cover layer a.

[0096] In some embodiments, a passive structure is grown on the surface of the empty area A, and the passive structure includes two layers of InGaAsP passive waveguide structures, and the top, bottom and middle of the material are filled with InP material.

[0097] In some embodiments, the grating region 9144 uses a passive apodized chirped grating. By transforming the grating structure, wide-spectrum reflection with uniform reflectivity within the wavelength range can be achieved, thereby achieving stable output of optical power.

[0098] S140: Etching along the surface of the cap layer downward to the surface of the buffer layer to form a first active region, a passive grating region and a second active region.

[0099] In some embodiments, etching is performed along the surface of the cap layer downward to the surface of the buffer layer while retaining the light emitting region 914 a , thereby forming a first active region 9141 , a passive grating region 9142 , and a second active region 9143 .

[0100] S150: After the side surfaces of the first active area, the passive grating area and the second active area are completed, a sidewall current blocking layer is grown on both sides; an upper limiting layer, a contact layer and a top layer are grown upward along the surfaces of the first active area, the passive grating area and the second active area until an upper limiting layer, a contact layer and a top layer are formed in sequence; at the same time, the growth continues along the bottom surface of the buffer layer until a lower limiting layer is formed.

[0101] In some embodiments, after the side surfaces of the first active region 9141 , the passive grating region 9142 , and the second active region 9143 are completed, sidewall current blocking layers are grown on both sides.

[0102] It grows upward along the surfaces of the first active region 9141, the passive grating region 9142 and the second active region 9143 until an upper confinement layer, a contact layer and a top layer are formed in sequence; and at the same time, it continues to grow along the bottom surface of the buffer layer until a lower confinement layer is formed.

[0103] S160: Etching downwards along the projection area of ​​the passive grating region on the top layer to form a first electrical isolation groove, wherein a first partition and a second partition are respectively formed on both sides of the first electrical isolation groove.

[0104] In some embodiments, etching is performed downward along the projection area of ​​the passive grating region on the top layer to form a first electrical isolation groove 917. At the same time, a second electrical isolation groove 918 and a third electrical isolation groove 919 are respectively formed on both sides of the first electrical isolation groove 917. Exemplarily, on one side of the first electrical isolation groove 917, the top layer 911 is hollowed out downward to form the second electrical isolation groove 918, and the second electrical isolation groove 918 is located on one side of the light-emitting region 914a; on the other side of the first electrical isolation groove 917, the top layer 911 is hollowed out downward to form the third electrical isolation groove 919, and the third electrical isolation groove 919 is located on the other side of the light-emitting region 914a.

[0105] S170: growing a protection layer on the current top surface to form a top layer.

[0106] In some embodiments, a protection layer is grown on the current top surface, and the protection layer is a passivation layer, which plays a role of anti-oxidation, waterproofing, etc., so as to protect the gain chip 910.

[0107] S180: Opening electrode windows on the surfaces of the first partition and the second partition respectively.

[0108] In some embodiments, electrode window B and electrode window C are respectively opened on the surface of the first partition and the surface of the second partition.

[0109] S190: Fabricating electrodes on the surface of the electrode window to form a first electrode region and a second electrode region respectively.

[0110] In some embodiments, electrodes are fabricated on the surfaces of electrode window B and electrode window C to form a first electrode region 9111 and a second electrode region 9112 , respectively.

[0111] S200: Bottom surface at the lower limiting layer

[0112] Electrodes are fabricated on the surface to form a third electrode region.

[0113] In some embodiments, the bottom surface of the lower confinement layer 915 is thinned and electrode fabrication is performed to form a third electrode region, which is located at the bottom layer of the laser.

[0114] The third electrode region is electrically connected to the first electrode region 9111, and the first active region 9141 is located below the first electrode region 9111, thereby effectively injecting carriers into the first active region 9141. Similarly, the third electrode region is electrically connected to the second electrode region 9112, and the second active region 9143 is located below the second electrode region 9112, thereby effectively injecting carriers into the second active region 9143.

[0115] In some embodiments of the present disclosure, the first high-transmittance film 910d and the second high-transmittance film 910e are respectively plated at both ends of the gain chip 910. The first high-transmittance film 910d is disposed adjacent to the first active area 9141, which is beneficial to increase the transmittance of light incident on and out of the first active area 9141; the second high-transmittance film 910e is disposed adjacent to the second active area 9143, which is beneficial to increase the transmittance of light incident on and out of the second active area 9143.

[0116] In the tunable laser provided by the present disclosure, the grating region is located between the gain region and the optical amplification region. The optical amplification region is equivalent to an optical amplifier, which is integrated into the gain chip and connected to the optical amplification region through the grating region, thereby achieving optical power amplification, in order to output higher optical power.

[0117] In the present disclosure, the grating region can realize flat reflection spectrum light in a wide wavelength range, so the grating region serves as the first resonant end face of the resonant cavity, and the reflector serves as the second resonant end face of the resonant cavity. The selected light of a specific wavelength is reflected and oscillated back and forth between the grating region and the reflector. When the gain is greater than the loss, the spontaneous emission light emitted by the first active region is converted into stimulated emission to form laser output. The formed laser is transmitted to the second active region through the passive grating region, and the second active region amplifies the optical power of the laser according to the injected carriers, thereby increasing the laser output optical power.

[0118] In the present disclosure, the gain region and the optical amplification region are electrically isolated by the first electrical isolation groove, so the gain region and the optical amplification region can be tuned separately. For example, different currents can be provided to the gain region and the optical amplification region separately.

[0119] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A laser, characterized in that: It includes a packaging cavity, and the packaging cavity is provided with: Gain chips, including: A top layer, comprising a first electrode region and a second electrode region, wherein a first electrical isolation groove is formed between the first electrode region and the second electrode region; A bottom layer, comprising a third electrode region, wherein the third electrode region is electrically connected to the first electrode region and the second electrode region respectively to output carriers; The light-emitting layer is located between the top layer and the bottom layer, and includes a light-emitting area, wherein the light-emitting area includes: a first active region, located within a downwardly projected region of the first electrode region, to receive the carriers and to emit a light beam with a wide wavelength range according to the injected carriers; A passive grating region, located in the downward projection area of ​​the first electrical isolation groove, including a grating region and a waveguide region, and used to provide a first resonant end face for the laser; a second active region, located within a downwardly projected region of the second electrode region, to receive the carriers; a wavelength selection component, disposed on one side of the first active region, for selecting light of a specific wavelength from the light beam emitted from the first active region; a reflector, disposed at one side of the wavelength selection component, for providing a second resonant end facet for the laser, so that the light of a specific wavelength selected by the wavelength selection component oscillates between the first resonant end facet and the second resonant end facet to form laser light, and transmits the laser light to the second active region; The second active region is used to amplify the laser light according to the injected carriers.

2. The laser according to claim 1, characterized in that A contact layer and an upper limiting layer are respectively formed between the top layer and the light-emitting layer from top to bottom; A lower limiting layer is formed between the light-emitting layer and the bottom layer; The first electrical isolation groove extends downward to the contact layer, so that the contact layer is divided into a first contact region and a second contact region, wherein the first contact region is located below the first electrode region and the second contact region is located below the second electrode region.

3. The laser according to claim 1, characterized in that On one side of the first electrical isolation groove, a second electrical isolation groove is formed by hollowing out from the top layer downwards, and the second electrical isolation groove is located on one side of the light emitting area; On the other side of the first electrical isolation groove, a third electrical isolation groove is hollowed out downward from the top layer to form the third electrical isolation groove, and the third electrical isolation groove is located on the other side of the light emitting area.

4. The laser according to claim 1, characterized in that The grating region includes an apodized chirped grating.

5. The laser according to claim 1, characterized in that The two side end surfaces of the gain chip are respectively plated with a first anti-reflection film and a second anti-reflection film.

6. The laser according to claim 1, characterized in that An optical fiber adapter is provided on the outer wall of the packaging cavity, and the optical fiber adapter is located at one side of the second active area; The light amplified by the second active region is output through the optical fiber adapter.

7. The laser according to claim 6, characterized in that The optical fiber adapter, the gain chip, the wavelength selection component and the reflector are respectively arranged along one side to the other side of the packaging cavity; The second active region is closer to the optical fiber adapter than to the grating region.

8. A method for preparing a laser, applied to the laser according to any one of claims 1 to 7, wherein a gain chip is packaged in the laser, characterized in that: The preparation method includes a preparation method of the gain chip, and the preparation method of the gain chip includes: Growing a buffer layer, a multi-quantum well structure layer and a cap layer in sequence from bottom to top; Etching longitudinally downward along the local surface of the cap layer to the surface of the buffer layer to form a void area; A passive structure is grown on the surface of the empty area, wherein the passive structure includes two layers of passive waveguides, and a grating is made on the surface of the passive waveguide on the upper layer; then a grating cover layer is grown on the surface of the grating so that the grating cover layer is flush with the surface of the cover layer; Etching along the surface of the cap layer downward to the surface of the buffer layer to form a first active region, a passive grating region and a second active region respectively; After the side surfaces of the first active area, the passive grating area and the second active area are completed, a sidewall current blocking layer is formed on both sides; an upper limiting layer, a contact layer and a top layer are grown upward along the surfaces of the first active area, the passive grating area and the second active area until an upper limiting layer, a contact layer and a top layer are formed in sequence; and at the same time, the bottom surface of the buffer layer is continued to grow until a lower limiting layer is formed; Etching downwards along the projection area of ​​the passive grating region on the top layer to form a first electrical isolation groove, wherein a first partition and a second partition are respectively formed on both sides of the first electrical isolation groove; Opening electrode windows on the surfaces of the first subarea and the second subarea respectively, and performing electrode manufacturing to form a first electrode area and a second electrode area respectively; Electrode manufacturing is performed on the bottom surface of the lower confinement layer to form a third electrode region.

9. The method for preparing a laser according to claim 8, characterized in that: While forming the first electrical isolation groove, on one side of the first electrical isolation groove, hollowing out from the top layer downwards to form a second electrical isolation groove, wherein the second electrical isolation groove is located on one side of the light-emitting layer; On the other side of the first electrical isolation groove, a third electrical isolation groove is formed by hollowing out from the top layer downwards. The third electrical isolation groove is located on the other side of the light-emitting layer.

10. The method for preparing a laser according to claim 8, characterized in that: After the third electrode region is formed, a first anti-reflection film and a second anti-reflection film are respectively plated on both side end surfaces of the gain chip.

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