Laser chip

Abstract

A laser chip provided in the present invention. The laser chip comprises a first electrode layer, an active layer, a waveguide layer, and a second electrode layer, respectively. In an optical field propagation direction, the waveguide layer comprises a waveguide layer section I, a waveguide layer section II, and a waveguide layer section III. The waveguide layer section I uses a shallow-etched ridge waveguide structure, and the waveguide layer section III uses a deep-etched ridge waveguide structure. In order to improve the coupling efficiency between the waveguide layer section I and the waveguide layer section III, the waveguide layer section II is provided. In the optical field propagation direction, the waveguide layer section II is divided into a first connecting portion and a second connecting portion, the first connecting portion uses a shallow-etched ridge waveguide structure, and the second connecting portion uses a deep-etched ridge waveguide structure to realize continuity in etching depth. In addition, the second connecting portion comprises a first tapered section and a second tapered section, and the side walls, close to the ridge structure, in the first tapered section and the second tapered section progressively converge toward the ridge structure, achieving optical field mode matching, and improving the coupling efficiency of the laser chip.

Description

A laser chip

[0001] This disclosure claims priority to patent application number 202410154772.4 filed on February 2, 2024 with the China Patent Office and patent application number 202410154704.8 filed on February 2, 2024 with the China Patent Office, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of optical communication technology, and in particular to a laser chip. Background Art

[0003] With the rapid development of application markets such as big data, cloud computing, and artificial intelligence, the demand for data communication optical modules is also increasing rapidly. The optical device industry continues to develop towards higher speeds and lower power consumption. As key optical devices in optical communications, semiconductor laser chips face higher challenges. EML laser chips should have higher modulation rates, higher modulation efficiency, and wide temperature operating capabilities to meet the high-speed requirements of optical modules.

[0004] Summary of the Invention

[0005] The laser chip provided by the present disclosure comprises, from bottom to top, a first electrode layer; an active layer, comprising a first active layer partition, a second active layer partition, and a third active layer partition along the light field transmission direction; a waveguide layer, comprising, along the light field transmission direction, a first waveguide layer partition, stacked with the first active layer partition, the first waveguide layer partition comprising a ridge structure, a first ridge waveguide groove, and a second ridge waveguide groove provided on both sides of the ridge structure; the etching depth of the first ridge waveguide groove and the second ridge waveguide groove does not exceed the depth of the first active layer partition; a second waveguide layer partition, stacked with the second active layer partition, the second waveguide layer partition comprising a first connecting portion and a second connecting portion along the light field transmission direction; the first connecting portion comprising a ridge structure, a third ridge waveguide groove, and a fourth ridge waveguide groove provided on both sides of the ridge structure; the second connecting portion comprising a ridge structure, a fifth ridge waveguide groove, and a sixth ridge waveguide groove provided on both sides of the ridge structure; the third ridge waveguide groove The etching depths of the groove and the fourth ridge waveguide groove do not exceed the depth of the second partition of the active layer, and the etching depths of the fifth ridge waveguide groove and the sixth ridge waveguide groove exceed the depth of the second partition of the active layer; the fifth ridge waveguide groove includes a first gradient portion, and the sixth ridge waveguide groove includes a second gradient portion; the side walls close to the ridge structure in the first gradient portion and the second gradient portion gradually move closer to the ridge structure; the third partition of the waveguide layer is stacked with the third partition of the active layer, and the third partition of the waveguide layer includes a ridge structure, a seventh ridge waveguide groove and an eighth ridge waveguide groove arranged on both sides of the ridge structure; the etching depths of the seventh ridge waveguide groove and the eighth ridge waveguide groove exceed the depth of the third partition of the active layer; the second electrode layer includes a light-emitting electrode region and a modulation electrode region; the first electrode layer and the light-emitting electrode region provide carriers to the first partition of the active layer to emit light; the first electrode layer and the modulation electrode region provide a modulation current to the third partition of the active layer to modulate the light. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] To more clearly illustrate the technical solutions of the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure, and those skilled in the art can also derive other drawings based on these drawings. Furthermore, the drawings described below are schematic diagrams and are not intended to limit the actual dimensions of the products, actual processes of the methods, actual timing of signals, and the like involved in the embodiments of the present disclosure.

[0007] FIG1 is a partial architecture diagram of an optical communication system according to some embodiments of the present disclosure;

[0008] FIG2 is a partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0009] FIG3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0010] FIG4 is an exploded view of an optical module according to some embodiments of the present disclosure;

[0011] FIG5 is a structural diagram of a light emitting component provided according to some embodiments of the present disclosure;

[0012] FIG6 is an exploded view of a light emitting component according to some embodiments of the present disclosure;

[0013] FIG7 is a structural diagram of a laser chip provided according to some embodiments of the present disclosure;

[0014] FIG8 is an exploded structural diagram of a laser chip provided according to some embodiments of the present disclosure;

[0015] FIG9 is a structural diagram of a waveguide layer in a laser chip according to some embodiments of the present disclosure;

[0016] FIG10 is a structural diagram of a second partition of a waveguide layer according to some embodiments of the present disclosure;

[0017] FIG11 is a schematic diagram showing the relative relationship between the light-emitting region, the transition region, and the electro-absorption modulation region in a laser chip according to some embodiments of the present disclosure;

[0018] FIG12 is a top view of a laser chip according to some embodiments of the present disclosure;

[0019] FIG13 is a schematic diagram of etching partitions of a laser chip according to some embodiments of the present disclosure;

[0020] FIG14 is a cross-sectional structural diagram of a light-emitting region in a laser chip according to some embodiments of the present disclosure;

[0021] FIG15 is a first cross-sectional structural diagram of a transition region in a laser chip according to some embodiments of the present disclosure;

[0022] FIG16 is a second cross-sectional structural diagram of a transition region in a laser chip according to some embodiments of the present disclosure;

[0023] FIG17 is a cross-sectional structural diagram of an electro-absorption modulation region in a laser chip according to some embodiments of the present disclosure;

[0024] FIG18 is a schematic diagram of an exploded structure of a laser chip provided according to some embodiments of the present disclosure;

[0025] FIG19 is a partial structural diagram of a laser chip provided according to some embodiments of the present disclosure;

[0026] FIG20 is a schematic diagram of etching partitions of a waveguide layer in a laser chip according to some embodiments of the present disclosure;

[0027] FIG21 is a cross-sectional structural diagram of a light-emitting region in a laser chip according to some embodiments of the present disclosure;

[0028] FIG22 is a cross-sectional structural diagram of a transition region in a laser chip according to some embodiments of the present disclosure;

[0029] FIG23 is a cross-sectional structural diagram of an electro-absorption modulation region in a laser chip according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0030] Some embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, the embodiments described are only some of the embodiments of the present disclosure, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments provided in the present disclosure are within the scope of protection of the present disclosure.

[0031] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as open and inclusive, that is, "including, but not limited to"; the terms "first" and "second" are not to be understood as indicating or implying relative importance or indicating an upper limit on quantity; the term "plurality" means two or more; the term "connected" is to be understood in a broad sense, for example, "connected" can be a fixed connection, a detachable connection, or an integral connection, and can be directly connected or indirectly connected through an intermediate medium; the use of the terms "suitable for" or "configured to" means open and inclusive language, which does not exclude equipment that is suitable for or configured to perform additional tasks or steps; terms such as "parallel", "perpendicular", "same", "consistent", "level" and so on are not limited to absolute mathematical theoretical relationships, but also include acceptable error ranges generated in practice, and also include differences based on the same design concept but due to manufacturing reasons.

[0032] In optical communication technology, to establish information transmission between information processing devices, it is necessary to load the information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When transmitting optical signals within information transmission equipment, they can reduce optical power loss, thereby enabling high-speed, long-distance, and low-cost information transmission. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment typically includes optical network units (ONUs), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment typically includes optical fibers and optical waveguides.

[0033] Optical modules can convert optical signals into electrical signals between information processing devices and information transmission devices. For example, at least one of the optical signal input or output ends of an optical module is connected to an optical fiber, and at least one of the electrical signal input or output ends of the optical module is connected to an optical network terminal. A first optical signal from the optical fiber is transmitted to the optical module, which converts the first optical signal into a first electrical signal and transmits the first electrical signal to the optical network terminal. A second electrical signal from the optical network terminal is transmitted to the optical module, which converts the second electrical signal into a second optical signal and transmits the second optical signal to the optical fiber. Because multiple information processing devices can transmit information via electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, rather than all of them. Here, the information processing device directly connected to the optical module is referred to as the optical module's host computer. Furthermore, the optical signal input or output end of the optical module can be referred to as an optical port, and the electrical signal input or output end of the optical module can be referred to as an electrical port.

[0034] Figure 1 is a partial structural diagram of an optical communication system provided according to some embodiments of the present disclosure. As shown in Figure 1, 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.

[0035] One end of optical fiber 101 extends toward remote information processing device 1000, and the other end of optical fiber 101 is connected to optical module 200 through the optical port of optical module 200. Optical signals can be totally reflected in optical fiber 101, and the propagation of the optical signal in the direction of total reflection can almost maintain the original optical power. The optical signal undergoes multiple total reflections in optical fiber 101 to transmit the optical signal from remote information processing device 1000 to optical module 200, and vice versa, thereby achieving long-distance, low-power information transmission.

[0036] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 may be 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 operating status of the optical module 200.

[0037] 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 to establish a unidirectional or bidirectional electrical signal connection between the host computer 100 and the optical module 200.

[0038] The host computer 100 also includes an external electrical interface that can access an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104. The network cable interface 104 is configured to access a 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 that an electrical signal connection is established between the local information processing device 2000 and the host computer 100 via the network cable 103. For example, a third electrical signal emitted by the local information processing device 2000 is transmitted to the host computer 100 via the network cable 103. The host computer 100 generates a second electrical signal based on the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200. 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. The second optical signal is then transmitted to the remote information processing device 1000 via the optical fiber 101. For example, a first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101. The first optical signal from the optical fiber 101 is transmitted to the optical module 200. The optical module 200 converts the first optical signal into a first electrical signal. The optical module 200 transmits the first electrical signal to the host computer 100. The host computer 100 generates a fourth electrical signal based on the first electrical signal and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that optical modules are tools for converting optical signals into electrical signals. During this conversion process, the information does not change, but the encoding and decoding methods of the information can change.

[0039] 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.

[0040] FIG2 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, FIG2 only shows the structure of the host computer 100 related to the optical module 200. As shown in FIG2, the host computer 100 also 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 connect to the electrical port of the optical module 200; the heat sink 107 has a protruding structure such as fins that increase the heat dissipation area.

[0041] The optical module 200 is inserted into the cage 106 of the host computer 100. The cage 106 secures the optical module 200. Heat generated by the optical module 200 is transferred to the cage 106 and then dissipated through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 connects with the electrical connector inside the cage 106, thereby establishing a bidirectional electrical signal connection between the optical module 200 and the host computer 100. Furthermore, the optical port of the optical module 200 connects to the optical fiber 101, thereby establishing a bidirectional optical signal connection between the optical module 200 and the optical fiber 101.

[0042] Figure 3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure, and Figure 4 is an exploded view of an optical module provided according to some embodiments of the present disclosure. As shown in Figures 3 and 4, the optical module 200 includes a housing, a circuit board 300 disposed within the housing, a light emitting component 400, and a light receiving component 500. However, the present disclosure is not limited thereto. In some embodiments, the optical module 200 includes either the light emitting component 400 or the light receiving component 500.

[0043] The housing includes 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.

[0044] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicular to the base 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.

[0045] In some embodiments, the lower shell 202 includes a base plate 2021 and two lower side plates 2022 located on both sides of the base plate 2021 and arranged perpendicularly to the base 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 arranged perpendicularly to the cover plate 2011. The two upper side plates are combined with the two lower side plates 2022 to achieve the upper shell 201 covering the lower shell 202.

[0046] The direction of the line connecting the two openings 204 and 205 can be consistent with the length direction of the optical module 200, or it can 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 (the right end in Figure 3), and the opening 205 is also located at the end of the optical module 200 (the left end in Figure 3). Alternatively, the opening 204 is located at the end of the optical module 200, and the opening 205 is located on 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 connect to the external optical fiber 101, so that the optical fiber 101 connects the light emitting component 400 and the light receiving component 500 in the optical module 200.

[0047] The combined assembly of the upper housing 201 and the lower housing 202 facilitates the installation of the circuit board 300, the light emitting component 400, the light receiving component 500, and the like within the housing. The upper housing 201 and the lower housing 202 provide encapsulation and protection for these components. Furthermore, during assembly of the circuit board 300, the light emitting component 400, and the light receiving component 500, the positioning components, heat dissipation components, and electromagnetic shielding components of these components are easily positioned, facilitating automated production.

[0048] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0049] 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.

[0050] For example, the unlocking component 600 is located on the outside of the two lower side panels 2022 of the lower housing 202 and includes a snap-fit ​​component that mates with 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 secures 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 between the snap-fit ​​component and the host computer, thereby releasing the optical module 200 from the cage 106 and allowing the optical module 200 to be removed from the cage 106.

[0051] The circuit board 300 includes circuit traces, electronic components, and chips. The electronic components and chips are connected according to the circuit design through the circuit traces to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include, for example, microcontroller units (MCUs), laser driver chips, transimpedance amplifiers (TIAs), limiting amplifiers, clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0052] 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.

[0053] The circuit board 300 also includes a gold finger 301 formed on its end surface, and 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 set only on the surface of one side of the circuit board 300 (for example, the upper surface shown in Figure 4), or it can be set on the upper and lower surfaces of the circuit board 300 to provide a larger number of pins, thereby adapting to occasions where a large number of pins are required. 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.

[0054] At least one of the light emitting component 400 or the light receiving component 500 is located on a side of the circuit board 300 away from the gold finger 301 .

[0055] In some embodiments, the light emitting component 400 and the light receiving component 500 are physically separated from the circuit board 300 and then electrically connected to the circuit board 300 through corresponding flexible circuit boards or electrical connectors.

[0056] In some embodiments, at least one of the light emitting component or the light receiving component may be directly disposed on the circuit board 300. For example, at least one of the light emitting component or the light receiving component may be disposed on a surface of the circuit board 300 or a side of the circuit board 300.

[0057] As shown in FIG4 , in the optical module provided in this embodiment, the light emitting component 400 and the light receiving component 500 are both arranged on the round square tube body. The light emitting component 400 is used to generate and output signal light, and the light receiving component 500 is used to receive signal light from outside the optical module. An optical fiber adapter is provided on the round square tube body, and the optical fiber adapter is used to realize the connection between the optical module and the external optical fiber. A lens assembly is usually provided in the round square tube body, and the lens assembly is used to change the propagation direction of the signal light output by the light emitting component 400 or the signal light input by the external optical fiber. The light emitting component 400 and the light receiving component 500 are physically separated from the circuit board 300, so it is difficult for the light emitting component 400 and the light receiving component 500 to be directly connected to the circuit board 300. Therefore, in the embodiment of the present disclosure, the light emitting component 400 and the light receiving component 500 are electrically connected respectively through a flexible circuit board. However, in the embodiment of the present disclosure, the assembly structure of the light emitting component 400 and the light receiving component 500 is not limited to the structure shown in Figures 3 and 4, and can also be other assembly combination structures, such as the light emitting component 400 and the light receiving component 500 are arranged on different tube bodies. This embodiment only takes the structure shown in Figures 3 and 4 as an example.

[0058] Figure 5 is a structural diagram of a light emitting component provided according to some embodiments of the present disclosure. As shown in Figure 5, the light emitting component 400 provided in this embodiment includes a tube base 490, a tube cap 480, and other components disposed within the tube cap 480 and tube base 490. The tube cap 480 is disposed on one end of the tube base 490. The tube base 490 includes a number of pins, which are used to electrically connect the flexible circuit board to other electrical components within the light emitting component 400, and further to electrically connect the light emitting component 400 to the circuit board 300. This embodiment only uses the structure shown in Figure 5 as an example.

[0059] FIG6 is an exploded view of a light emitting component according to some embodiments of the present disclosure. As shown in FIG6 , the light emitting component 400 includes a laser assembly 410 , which generates signal light and transmits the generated signal light through a cap 480 .

[0060] In some embodiments, laser assembly 410 includes a laser chip 900 and a substrate. Circuitry is laid on the upper surface of the substrate, and the laser chip 900 is connected to the corresponding circuitry on the substrate via wire bonding. For example, laser chip 900 may be an electro-absorption module laser (EML) chip, which is a monolithic integration of a DFB laser and an EAM modulator. By using external modulation technology, EML laser chips avoid the interaction between photons and electrons in the laser during high-speed modulation, reducing the large chirp caused by direct modulation, thereby enabling higher-speed transmission.

[0061] Key performance indicators of the laser chip 900 include low power consumption, modulation rate, and modulation efficiency. A higher modulation rate improves the laser's bandwidth performance.

[0062] Figure 7 shows the structure of a laser chip according to some embodiments of the present disclosure; Figure 8 shows an exploded view of a laser chip according to some embodiments of the present disclosure. As shown in Figures 7 and 8, laser chip 900 may be an EML laser chip. The X direction indicated in Figures 7 and 8 represents the direction of light field transmission.

[0063] The laser chip 900 may include a first electrode layer 901 . The first electrode layer 901 is located at the bottom of the laser chip 900 .

[0064] The laser chip 900 may include an active layer 902 . The active layer 902 is located above the first electrode layer 901 .

[0065] Along the light field transmission direction, the active layer 902 includes a first active layer partition, a second active layer partition, and a third active layer partition. The first active layer partition, the second active layer partition, and the third active layer partition are sequentially arranged along the X direction.

[0066] The laser chip 900 may include a waveguide layer 903 . The waveguide layer 903 is located above the active layer 902 .

[0067] Along the light field transmission direction, the waveguide layer 903 includes a first waveguide layer partition 917, a second waveguide layer partition 924, and a third waveguide layer partition 934. The first waveguide layer partition 917, the second waveguide layer partition 924, and the third waveguide layer partition 934 are arranged in sequence along the X direction.

[0068] The first partition of the active layer is stacked with the first partition of the waveguide layer 917. The first partition of the active layer is located below the first partition of the waveguide layer 917.

[0069] The second partition of the active layer is stacked with the second partition of the waveguide layer 924. The second partition of the active layer is located below the second partition of the waveguide layer 924.

[0070] The third partition of the active layer is stacked with the third partition of the waveguide layer 934. The third partition of the active layer is located below the third partition of the waveguide layer 934.

[0071] The laser chip 900 may include a second electrode layer 904. The second electrode layer 904 is located above the waveguide layer 903. The waveguide layer 903 may include a light emitting electrode region 919 and a modulation electrode region 936.

[0072] The first electrode layer 901 and the light-emitting electrode region 919 provide carriers to the first sub-region of the active layer to emit light.

[0073] The first electrode layer 901 and the modulation electrode region 936 provide a modulation current to the third sub-region of the active layer to modulate the light emitted by the first sub-region of the active layer.

[0074] In some embodiments, by providing a reverse bias voltage and a modulation current to the third partition of the active layer, the light emitted by the first partition of the active layer has parameters such as phase, intensity, and frequency. Under the action of the reverse bias voltage, one of these parameters changes according to the law of the modulation current signal, thereby modulating the parameter, such as achieving intensity modulation.

[0075] Light can be emitted by providing carriers to the first active layer sub-area. Therefore, the first active layer sub-area and the first waveguide layer sub-area 917 are stacked to form a light-emitting region of the laser chip 900. The light-emitting region is a functionally divided region of the laser chip 900.

[0076] By providing a reverse bias voltage and a modulation current to the third partition of the active layer, the light emitted by the light-emitting area can be modulated. Therefore, the third partition of the active layer and the third partition of the waveguide layer 934 are stacked to form the electro-absorption modulation area of ​​the laser chip 900.

[0077] Cutting downward along the dotted line in Figure 8 , the first waveguide layer section 917 and its upper and lower structural layers constitute the light-emitting region of the laser chip 900. The third waveguide layer section 934 and its upper and lower structural layers constitute the electro-absorption modulation region of the laser chip 900. The area between the two dotted lines lies between the light-emitting region and the electro-absorption modulation region.

[0078] Figure 9 is a structural diagram of a waveguide layer in a laser chip according to some embodiments of the present disclosure. As shown in Figure 9, in the present disclosure, the waveguide layer 903 may adopt a ridge waveguide structure.

[0079] The ridge waveguide of the first waveguide layer partition 917 includes a ridge structure 9171, and a first ridge waveguide trench 9172 and a second ridge waveguide trench 9173 provided on both sides of the ridge structure 9171. The ridge structure 9171 protrudes relative to the first ridge waveguide trench 9172 and the second ridge waveguide trench 9173 on both sides.

[0080] The ridge waveguide of the third subarea 934 of the waveguide layer includes a ridge structure 9341, and a seventh ridge waveguide groove 9342 and an eighth ridge waveguide groove 9343 provided on both sides of the ridge structure 9341. The ridge structure 9341 protrudes relative to the seventh ridge waveguide groove 9342 and the eighth ridge waveguide groove 9343 on both sides.

[0081] Ridge waveguide grooves are formed on both sides of the ridge structure through an etching process. Ridge waveguides are classified into shallow-etched and deep-etched ridge waveguide structures based on the etch depth of the ridge waveguide grooves. A shallow-etched ridge waveguide structure is one in which the ridge waveguide grooves are etched down to a depth that does not exceed the depth of the corresponding active layer. A deep-etched ridge waveguide structure is one in which the ridge waveguide grooves are etched down to a depth that exceeds the depth of the corresponding active layer.

[0082] In this disclosure, Al-containing quantum wells can be used as the material for the first subregion of the active layer. When current is injected into the first subregion of the active layer, photons are generated, leading to light emission. Furthermore, Al-containing quantum wells have a larger valence band step, which better binds electrons. Therefore, Al-containing quantum wells enable the laser chip to operate over a wide temperature range, eliminating the need for energy-intensive semiconductor coolers and facilitating low power consumption for the laser chip.

[0083] Since the first partition of the active layer uses Al-containing quantum well as the material, and Al is easily oxidized, the first partition 917 of the waveguide layer adopts a shallow etched ridge waveguide structure, that is, the downward etching depth of the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173 does not exceed the depth of the first partition of the active layer.

[0084] The first partition 917 of the waveguide layer adopts a shallow etched ridge waveguide structure, so that the first partition of the active layer is located below the first partition 917 of the waveguide layer and is protected, thereby preventing the Al-containing quantum well from being directly exposed to the air and causing oxidation failure.

[0085] As the etching depth increases, the effective refractive index difference at the ridge waveguide location increases, and the confinement effect on the light field becomes stronger. More of the light field is confined within the deeply etched ridge waveguide structure, resulting in a higher optical confinement factor. The optical confinement factor is proportional to the modulation efficiency, thus enhancing the modulation efficiency of the electro-absorption modulation zone. For this reason, the ridge waveguides in the third sub-area 934 of the waveguide layer adopt a deeply etched ridge waveguide structure. When the third sub-area 934 of the waveguide layer adopts a deeply etched ridge waveguide structure, the optical confinement factor is stronger, allowing the third sub-area 934 of the waveguide layer to adopt a smaller ridge width, thereby enhancing the modulation rate of the electro-absorption modulation zone. Therefore, in the present disclosure, the use of a deeply etched ridge waveguide structure in the third sub-area 934 of the waveguide layer can simultaneously improve modulation efficiency and modulation rate.

[0086] The third subregion 934 of the waveguide layer adopts a deep-etched ridge waveguide structure to simultaneously improve the modulation efficiency and modulation rate of the laser chip 900 .

[0087] As the etching depth increases, the effective refractive index difference at the ridge waveguide position becomes larger, and the limiting effect on the light field becomes stronger. More light fields will be confined in the deeply etched ridge waveguide structure, and the corresponding light field mode spot will also be smaller.

[0088] In the present disclosure, the first waveguide layer section 917 employs a shallow-etched ridge waveguide structure, while the third waveguide layer section 934 employs a deep-etched ridge waveguide structure. Consequently, the light field mode spot of the light transmitted within the first waveguide layer section 917 is larger, while the light field mode spot of the light transmitted within the third waveguide layer section 934 is smaller. Consequently, the light field modes of the first waveguide layer section 917 and the third waveguide layer section 934 do not match, resulting in a sudden change in the light field mode interface. Directly connecting the first waveguide layer section 917 and the third waveguide layer section 934 would inevitably reduce coupling efficiency due to the light field mode mismatch. To this end, the present disclosure provides an active layer section 924 between the first and third active layer sections, and a second waveguide layer section 924 between the first and third waveguide layer sections 917 and 934. The active layer section 924 and the second waveguide layer section 924 are stacked together to form a transition region. The transition region lies between the light-emitting region and the electro-absorption modulation region. The transition region is the area between the two dashed lines in Figure 9.

[0089] Figure 10 illustrates the structure of a second waveguide layer partition according to some embodiments of the present disclosure. As shown in Figure 10 , the second waveguide layer partition 924 is located between the first waveguide layer partition 917 and the third waveguide layer partition 934. One end of the second waveguide layer partition 924 is connected to the first waveguide layer partition 917, and the other end is connected to the third waveguide layer partition 934.

[0090] The second subarea 924 of the waveguide layer along the light field transmission direction includes a first connecting portion 924a and a second connecting portion 924b. The first connecting portion 924a and the second connecting portion 924b are divided by the etching depth.

[0091] The first connection portion 924a may adopt a shallow etched ridge waveguide structure, and the second connection portion 924b may adopt a deep etched ridge waveguide structure.

[0092] The first connection portion 924a may include a ridge structure 9241a, a third ridge waveguide trench 9242a, and a fourth ridge waveguide trench 9243a respectively provided on both sides of the ridge structure 9241a.

[0093] The second connection portion 924b includes a ridge structure 9241b, a fifth ridge waveguide trench 9242b, and a sixth ridge waveguide trench 9243b respectively provided on both sides of the ridge structure 9241b.

[0094] To achieve continuity in etching depth with the first waveguide layer subsection 917, the first connecting portion 924a employs a shallow-etched ridge waveguide structure. To achieve continuity in etching depth with the third waveguide layer subsection 934, the second connecting portion 924b employs a deep-etched ridge waveguide structure. The transition zone allows for a transition in etching depth, avoiding abrupt interfaces at different etching depths and, consequently, minimizing optical field loss and reflection.

[0095] The first connecting portion 924a adopts a shallow etched ridge waveguide structure, and the downward etching depth of the third ridge waveguide groove 9242a and the fourth ridge waveguide groove 9243a does not exceed the depth of the corresponding second partition of the active layer.

[0096] The second connecting portion 924b adopts a deep-etched ridge waveguide structure, and the fifth ridge waveguide groove 9242b and the sixth ridge waveguide groove 9243b are etched downward to a depth exceeding the depth of the corresponding second partition of the active layer.

[0097] To achieve a smooth transition of the light field mode from the first waveguide layer subsection 917 to the third waveguide layer subsection 934 and improve coupling efficiency, the fifth ridge waveguide trench 9242b in the second connecting portion 924b includes a first gradual transition portion 9245b and a first non-gradient transition portion 9244b. The sixth ridge waveguide trench 9243b includes a second gradual transition portion 9247b and a second non-gradient transition portion 9246b. The first gradual transition portion 9245b is located at the end facing the first connecting portion 924a. The second gradual transition portion 9247b is located at the end facing the first connecting portion 924a.

[0098] The first gradual transition portion 9245b has a first sidewall 92451. The second gradual transition portion 9247b has a second sidewall 92471. The first sidewall 92451 and the second sidewall 92471 are sidewalls close to the ridge structure 9241b.

[0099] The surface of the closed area formed by the first gradient portion 9245b and the first non-gradient portion 9244b is recessed relative to the surface of the third ridge waveguide groove 9242a, that is, the surface is lower. Exemplarily, the closed area formed by the first gradient portion 9245b and the first non-gradient portion 9244b is hollowed out to a certain depth.

[0100] The surface of the enclosed region formed by the first gradually transitioning portion 9245b and the first non-gradient portion 9244b is lower than the surface of the remaining region in the fifth ridge waveguide trench 9242b. The remaining region in the fifth ridge waveguide trench 9242b refers to the remaining region in the fifth ridge waveguide trench 9242b excluding the enclosed region formed by the first gradually transitioning portion 9245b and the first non-gradient portion 9244b.

[0101] Similarly, the surface of the enclosed area formed by the second gradient portion 9247b and the second non-gradient portion 9246b is recessed relative to the surface of the fourth ridge waveguide groove 9243a, that is, the surface is lower. Exemplarily, the enclosed area formed by the second gradient portion 9247b and the second non-gradient portion 9246b is hollowed out downward to a certain depth.

[0102] The surface of the enclosed region formed by the second gradient portion 9247b and the second non-gradient portion 9246b is lower than the surface of the remaining region in the sixth ridge waveguide trench 9243b. The remaining region in the sixth ridge waveguide trench 9243b refers to the remaining region in the sixth ridge waveguide trench 9243b excluding the enclosed region formed by the second gradient portion 9247b and the second non-gradient portion 9246b.

[0103] The light field pattern output from the first waveguide layer subsection 917 is relatively large and may be transmitted along the ridge structure 9241a and the areas on either side. When the light field is transmitted to the first sidewall 92451, at the same top surface height, the medium within the enclosed region formed by the first sidewall 92451, the first gradient portion 9245b, and the first non-gradient portion 9244b is air, while the medium in the region outside the enclosed region from the first sidewall 92451 is semiconductor material. Therefore, the light field pattern is transmitted along the peripheral semiconductor material with a higher refractive index. The same transmission principle applies to the second sidewall 92471. The transmission area of ​​the light field pattern at the second connecting portion 924b is indicated by the shaded area in Figure 10.

[0104] Along the direction from the first connecting portion 924a to the second connecting portion 924b, the first sidewall 92451 and the second sidewall 92471 can gradually move closer to the ridge structure 9241b. Consequently, the width of the semiconductor material enclosed by the first sidewall 92451 and the ridge structure 9241b gradually decreases, and the width of the semiconductor material enclosed by the second sidewall 92471 and the ridge structure 9241b gradually decreases, thereby gradually reducing the light field pattern of the first subsection 917 of the waveguide layer. The light field mode spots transmitted by the ridge structure 9241a and the semiconductor materials on both sides of the ridge structure 9241a are gradually gathered into the ridge structure 9241b, thereby realizing a smooth transition of the light field modes between the first partition 917 of the waveguide layer and the third partition 934 of the waveguide layer, so as to match the light field modes between the first partition 917 of the waveguide layer and the third partition 934 of the waveguide layer, thereby avoiding the formation of a sudden light field mode interface between the shallowly etched ridge waveguide structure and the deeply etched ridge waveguide structure, thereby avoiding light field loss and reflection, and thus improving the coupling efficiency between the first partition 917 of the waveguide layer and the third partition 934 of the waveguide layer.

[0105] Cutting downward along the dotted lines in Figure 8 , the first waveguide layer section 917 and its upper and lower structural layers constitute the light-emitting region of laser chip 900. The third waveguide layer section 934 and its upper and lower structural layers constitute the electro-absorption modulation region of laser chip 900. The area between the two dotted lines is the transition region. Therefore, functionally, laser chip 900 comprises a light-emitting region, an electro-absorption modulation region, and a transition region. The transition region is located between the light-emitting region and the electro-absorption modulation region. Furthermore, structurally, laser chip 900 comprises, from bottom to top, a first electrode layer 901, an active layer 902, a waveguide layer 903, and a second electrode layer 904.

[0106] Figure 11 illustrates the relative relationship between the light-emitting region, transition region, and electro-absorption modulation region of a laser chip according to some embodiments of the present disclosure. Figure 12 illustrates a top-down structural diagram of a laser chip according to some embodiments of the present disclosure. As shown in Figures 11 and 12, the waveguide structure of laser chip 900 can employ a ridge waveguide structure.

[0107] The laser chip 900 may include a light emitting region 910. The light emitting region 910 is configured to emit light that does not carry a signal.

[0108] The laser chip 900 may include an electro-absorption modulation region 930. The electro-absorption modulation region 930 is configured to perform signal modulation on the light emitted from the light emitting region 910 to generate an optical signal.

[0109] The laser chip 900 may include a transition region 920 . The transition region 920 is disposed between the light emitting region 910 and the electro-absorption modulation region 930 .

[0110] The transition zone 920 can realize the transition of etching depth between the light-emitting zone 910 and the electro-absorption modulation zone 930, as well as the transition of light field mode between the light-emitting zone 910 and the electro-absorption modulation zone 930, avoiding the occurrence of etching depth mutation interface and light field mode mutation interface, thereby avoiding light field loss and reflection, and ultimately improving the coupling efficiency between the light-emitting zone 910 and the electro-absorption modulation zone 930.

[0111] In some embodiments, the light-emitting region 910, transition region 920, and electro-absorption modulation region 930 are sequentially arranged along the direction of light field transmission. The light-emitting end of the light-emitting region 910 is connected to the light-incoming end of the transition region 920. The light-emitting end of the transition region 920 is connected to the light-incoming end of the electro-absorption modulation region 930. It is understood that the direction of light field transmission can be light-emitting region 910 → transition region 920 → electro-absorption modulation region 930.

[0112] Figure 13 is a schematic diagram of the etched zones of a laser chip according to some embodiments of the present disclosure. As shown in Figure 13, the light-emitting region 910, transition region 920, and electro-absorption modulation region 930 of laser chip 900 are sequentially arranged along the direction of light field transmission. The waveguide structure of laser chip 900 can adopt a ridge waveguide structure.

[0113] The ridge waveguide of the laser chip 900 may include a ridge structure.

[0114] The ridge waveguide of the laser chip 900 may include ridge waveguide grooves respectively provided on both sides of the ridge structure, wherein the ridge structure protrudes relative to the ridge waveguide grooves on both sides.

[0115] The light emitting region 910, the transition region 920, and the electro-absorption modulation region 930 each have a ridge structure and ridge waveguide grooves on both sides. In some embodiments, the ridge waveguide grooves on both sides are symmetrically arranged on both sides of the ridge structure.

[0116] In some embodiments, the light emitting region 910 may include, from bottom to top, a first electrode layer, a first sub-area of ​​the active layer, and a light emitting electrode region. The first electrode layer in the light emitting region is the portion of the light emitting region corresponding to the first electrode layer 901 .

[0117] The first electrode layer may be an N-type electrode layer configured to inject N-type carriers into the active layer, and the light-emitting electrode region may be a P-type electrode layer configured to inject P-type carriers into the active region.

[0118] When the light-emitting electrode region forms a PN junction with the first electrode layer, the carrier concentration difference causes diffusion. This carrier diffusion results in holes and negative ions in the light-emitting electrode region, and electrons and positive ions in the first electrode layer. Based on the charge principle, holes are driven downward into the first subsection of the active layer, while electrons are driven upward into the first subsection of the active layer. Therefore, the light-emitting electrode region is used to inject holes, which are P-type carriers, into the first subsection of the active layer; the first electrode layer is used to inject electrons, which are N-type carriers, into the first subsection of the active layer. Within the first subsection of the active layer, stimulated emission causes discrete electron-hole pairs to recombine, generating photons. This effectively converts the electrically injected carriers into photons and generates gain light. The photons generated by recombination within the first subsection of the active layer are reflected by the resonant cavity or distributed feedback grating, forming positive feedback, thereby generating lasing light.

[0119] The first partition of the active layer can adopt a quantum well structure of III-V mixed materials, such as InGaAsP quantum well, etc. III-V mixed materials are direct bandgap materials with strong linear electro-optical Pockels effect, which can easily realize optical gain function.

[0120] In some embodiments, laser chip 900 achieves low power consumption by eliminating the energy-intensive semiconductor cooler. This requires laser chip 900 to operate over a wide temperature range. The distribution of charge carriers in quantum wells follows the Fermi distribution. As the temperature rises, the distribution of high-energy electrons in the quantum wells increases, making it easier for electrons to escape from the quantum wells, resulting in a decrease in internal quantum efficiency.

[0121] For example, the first subregion of the active layer may be an InGaAsP quantum well. Since the valence band step of the InGaAsP quantum well structure is small and the electron binding ability is weak, it is difficult to operate in a wide temperature range.

[0122] For example, the first subregion of the active layer can employ an Al-containing quantum well, such as an AlInGaAs quantum well. The valence band step of the Al-containing quantum well is approximately 0.1 eV lower than that of the InGaAsP quantum well, allowing for better electron confinement. Therefore, the AlInGaAs quantum well enables the laser chip to operate over a wide temperature range, eliminating the need for energy-intensive semiconductor coolers and facilitating low power consumption for the laser chip.

[0123] In this disclosure, the luminescent region 910 and the electro-absorption modulation region 930 employ ridge waveguide structures with different etch depths. For example, the first subregion of the waveguide layer corresponding to the luminescent region 910 employs a shallowly etched ridge waveguide structure, while the third subregion of the waveguide layer corresponding to the electro-absorption modulation region 930 employs a deeply etched ridge waveguide structure.

[0124] When the first partition of the active layer adopts an Al-containing quantum well, since Al is easily oxidized, when the first partition of the waveguide layer adopts a shallow-etched ridge waveguide structure, the first partition of the active layer is located below the ridge waveguide structure and is protected, thereby avoiding the problem of oxidation failure caused by direct exposure of the Al-containing quantum well to the air.

[0125] In the present disclosure, the first partition of the waveguide layer corresponding to the light-emitting region 910 adopts a shallow-etched ridge waveguide structure to protect the first partition of the active layer.

[0126] In the present disclosure, the third subregion of the waveguide layer corresponding to the electro-absorption modulation region 930 adopts a deep-etched ridge waveguide structure, which can improve both the modulation efficiency and the modulation rate.

[0127] As the etching depth increases, the effective refractive index difference at the ridge waveguide position becomes larger, and the limiting effect on the light field becomes stronger. More light fields will be confined in the deeply etched ridge waveguide structure, and the corresponding light field mode spot will also be smaller.

[0128] In the present disclosure, the first subregion 917 of the waveguide layer in the light-emitting region 910 employs a shallowly etched ridge waveguide structure, while the third subregion 934 of the waveguide layer in the electro-absorption modulation region 930 employs a deeply etched ridge waveguide structure. This results in a larger light field pattern transmitted within the light-emitting region 910, while a smaller light field pattern transmitted within the electro-absorption modulation region 930. Consequently, the light field modes between the light-emitting region 910 and the electro-absorption modulation region 930 do not match, resulting in an abrupt interface in the light field modes. Directly connecting the light-emitting region 910 and the electro-absorption modulation region 930 would inevitably reduce coupling efficiency due to the light field pattern mismatch. To address this issue, the present disclosure provides a transition region 920 between the light-emitting region 910 and the electro-absorption modulation region 930.

[0129] The waveguide layer corresponding to the transition region 920 is the second subregion 924 of the waveguide layer.

[0130] The second subarea 924 of the waveguide layer along the light field transmission direction includes a first connecting portion 924a and a second connecting portion 924b. The first connecting portion 924a and the second connecting portion 924b are divided by the etching depth.

[0131] The first connection portion 924a may adopt a shallow etched ridge waveguide structure, and the second connection portion 924b may adopt a deep etched ridge waveguide structure.

[0132] The first connection portion 924a may include a ridge structure 9241a, a third ridge waveguide trench 9242a, and a fourth ridge waveguide trench 9243a respectively provided on both sides of the ridge structure 9241a.

[0133] The second connection portion 924b includes a ridge structure 9241b, a fifth ridge waveguide trench 9242b, and a sixth ridge waveguide trench 9243b respectively provided on both sides of the ridge structure 9241b.

[0134] To achieve continuity in etching depth with the light-emitting region 910, the first connecting portion 924a utilizes a shallowly etched ridge waveguide structure. To achieve continuity in etching depth with the electro-absorption modulation region 930, the second connecting portion 924b utilizes a deeply etched ridge waveguide structure. The transition region allows for a transition in etching depth, avoiding large abrupt interfaces in the etching depth, thereby minimizing light field loss and reflection.

[0135] The first connecting portion 924a adopts a shallow etched ridge waveguide structure, and the downward etching depth of the third ridge waveguide groove 9242a and the fourth ridge waveguide groove 9243a does not exceed the depth of the corresponding second partition of the active layer.

[0136] The second connecting portion 924b adopts a deep-etched ridge waveguide structure, and the fifth ridge waveguide groove 9242b and the sixth ridge waveguide groove 9243b are etched downward to a depth exceeding the depth of the corresponding second partition of the active layer.

[0137] To achieve a smooth transition of the light field mode from the first waveguide layer subsection 917 to the third waveguide layer subsection 934 and improve coupling efficiency, the fifth ridge waveguide trench 9242b in the second connecting portion 924b includes a first gradual transition portion 9245b and a first non-gradient transition portion 9244b. The sixth ridge waveguide trench 9243b includes a second gradual transition portion 9247b and a second non-gradient transition portion 9246b. The first gradual transition portion 9245b is located at the end facing the first connecting portion 924a. The second gradual transition portion 9247b is located at the end facing the first connecting portion 924a.

[0138] The first gradual transition portion 9245b has a first sidewall 92451. The second gradual transition portion 9247b has a second sidewall 92471. The first sidewall 92451 and the second sidewall 92471 are sidewalls close to the ridge structure 9241b.

[0139] The surface of the closed area formed by the first gradient portion 9245b and the first non-gradient portion 9244b is recessed relative to the surface of the third ridge waveguide groove 9242a, that is, the surface is lower. Exemplarily, the closed area formed by the first gradient portion 9245b and the first non-gradient portion 9244b is hollowed out to a certain depth.

[0140] The surface of the enclosed region formed by the first gradually transitioning portion 9245b and the first non-gradient portion 9244b is lower than the surface of the remaining region in the fifth ridge waveguide trench 9242b. The remaining region in the fifth ridge waveguide trench 9242b refers to the remaining region in the fifth ridge waveguide trench 9242b excluding the enclosed region formed by the first gradually transitioning portion 9245b and the first non-gradient portion 9244b.

[0141] Similarly, the surface of the enclosed area formed by the second gradient portion 9247b and the second non-gradient portion 9246b is recessed relative to the surface of the fourth ridge waveguide groove 9243a, that is, the surface is lower. Exemplarily, the enclosed area formed by the second gradient portion 9247b and the second non-gradient portion 9246b is hollowed out downward to a certain depth.

[0142] The surface of the enclosed region formed by the second gradient portion 9247b and the second non-gradient portion 9246b is lower than the surface of the remaining region in the sixth ridge waveguide trench 9243b. The remaining region in the sixth ridge waveguide trench 9243b refers to the remaining region in the sixth ridge waveguide trench 9243b excluding the enclosed region formed by the second gradient portion 9247b and the second non-gradient portion 9246b.

[0143] The light field pattern output from the first waveguide layer subsection 917 is relatively large and may be transmitted along the ridge structure 9241a and the areas on either side. When the light field is transmitted to the first sidewall 92451, at the same top surface height, the medium within the enclosed region formed by the first sidewall 92451, the first gradient portion 9245b, and the first non-gradient portion 9244b is air, while the medium in the region outside the enclosed region from the first sidewall 92451 is semiconductor material. Therefore, the light field pattern is transmitted along the peripheral semiconductor material with a higher refractive index. The same transmission principle applies to the second sidewall 92471. The transmission area of ​​the light field pattern at the second connecting portion 924b is indicated by the shaded area in Figure 10.

[0144] Along the direction from the first connection portion 924a to the second connection portion 924b, the first side wall 92451 and the second side wall 92471 may gradually move closer to the ridge structure 9241b. The width of the semiconductor material enclosed by the first side wall 92451 and the ridge structure 9241b gradually decreases, and the width of the semiconductor material enclosed by the second side wall 92471 and the ridge structure 9241b gradually decreases, and the light field pattern spot emitted by the light-emitting area 910 gradually decreases. The light field pattern spot transmitted by the ridge structure 9241a and the semiconductor material on both sides of the ridge structure 9241a are gradually gathered into the ridge structure 9241b, thereby realizing a smooth transition of the light field mode between the light-emitting area 910 and the electro-absorption modulation area 930, so as to match the light field modes of the light-emitting area 910 and the electro-absorption modulation area 930, avoiding the formation of a light field mode mutation interface between the shallowly etched ridge waveguide structure and the deeply etched ridge waveguide structure, thereby avoiding light field loss and reflection, and thereby improving the coupling efficiency between the light-emitting area 910 and the electro-absorption modulation area 930.

[0145] In the present disclosure, along the direction from the first connecting portion 924a to the second connecting portion 924b, the first sidewall 92451 and the second sidewall 92471 gradually approach the ridge structure 9241b, achieving a smooth transition of the light field pattern between the light-emitting region 910 and the electro-absorption modulation region 930, thereby matching the light field pattern between the light-emitting region 910 and the electro-absorption modulation region 930. To ensure that the light field pattern emitted by the light-emitting region 910 is transmitted within the area defined by the first sidewall 92451 and the second sidewall 92471, the maximum distance between the first and second gradually transitioning portions 9245b and 9247b is greater than the size of the light field pattern emitted by the light-emitting region 910, thereby ensuring that the light field pattern emitted by the light-emitting region 910 is transmitted within the area defined by the first and second sidewalls 92451 and 92471.

[0146] Figure 14 illustrates a cross-sectional view of the light-emitting region of a laser chip according to some embodiments of the present disclosure. The structure shown in Figure 14 is obtained by sectioning the light-emitting region 910 along the Y direction indicated in Figure 11 . The Y direction is parallel to the direction of light field transmission. As shown in Figure 14 , in some embodiments, the light-emitting region 910 may include, from bottom to top, a first electrode layer 911, a substrate 912, a lower confinement layer 913, a first active layer subregion 914, an upper confinement layer 915, a grating layer 916, a first waveguide layer subregion 917, a passivation layer 918, and a light-emitting electrode region 919.

[0147] The first subarea 914 of the active layer is the active layer corresponding to the light-emitting area 910 .

[0148] The first subarea 917 of the waveguide layer is the waveguide layer corresponding to the light-emitting area 910 .

[0149] The first electrode layer 911 may be an N-type electrode layer configured to inject N-type carriers into the first partition 914 of the active layer.

[0150] The light emitting electrode region 919 may be a P-type electrode layer configured to inject P-type carriers into the first subregion 914 of the active layer.

[0151] When the light-emitting electrode region 919 forms a PN junction with the first electrode layer 911, the carrier concentration difference causes diffusion. This carrier diffusion results in the following: the light-emitting electrode region 919 injects holes, which are the aforementioned P-type carriers, into the first active layer subsection 914; and the first electrode layer 911 injects electrons, which are the aforementioned N-type carriers, into the first active layer subsection 914. Within the first active layer subsection 914, stimulated emission causes discrete electron-hole pairs to recombine, generating photons. This effectively converts the electrically injected carriers into photons, generating gain light.

[0152] The lower confinement layer 913 and the upper confinement layer 915 are respectively located on both sides of the active layer first subarea 914. The lower confinement layer 913 and the upper confinement layer 915 can confine the injected electrons and holes in the quantum well of the active layer first subarea 914, thereby ensuring the carrier concentration.

[0153] The first active layer subregion 914 utilizes an Al-containing quantum well, such as an AlInGaAs quantum well. The valence band step of the Al-containing quantum well is approximately 0.1 eV higher than that of the InGaAsP quantum well, allowing for better electron confinement. Therefore, the AlInGaAs quantum well enables the laser chip to operate over a wide temperature range, eliminating the need for energy-intensive semiconductor coolers and facilitating low power consumption for the laser chip.

[0154] Within the first active layer subsection 914, stimulated emission causes discrete electron-hole pairs to recombine and generate photons, effectively converting electrically injected carriers into photons and generating gain light. The gain light is reflected by the resonant cavity or distributed feedback grating, forming positive feedback, thereby generating lasing light. The grating layer 916 includes a distributed feedback grating (DFG) coupled to a Bragg grating (FBG). The grating layer 916 is typically located on the surface of the waveguide layer. The gain light undergoes feedback coupling within the grating layer 916. Since only light that meets the Bragg condition can form stable oscillations, the Bragg grating exhibits excellent frequency selection characteristics.

[0155] The first waveguide layer section 917 can be an InP waveguide layer having a ridge waveguide structure. The grating layer 916 is disposed on the bottom surface of the first waveguide layer section 917. The first waveguide layer section 917 includes a ridge structure 9171, and a first ridge waveguide trench 9172 and a second ridge waveguide trench 9173 disposed on either side of the ridge structure 9171. The ridge structure 9171 protrudes relative to the first ridge waveguide trench 9172 and the second ridge waveguide trench 9173 on either side.

[0156] The first ridge waveguide groove 9172 and the second ridge waveguide groove 9173 are formed by etching downward to a certain depth. In the present disclosure, the etching depth of the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173 is the depth H1 indicated in FIG10 . The etching depth of the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173 does not exceed the depth of the first partition 914 of the active layer. The deepest etching depth of the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173 is located above the first partition 914 of the active layer. The first partition 914 of the active layer is completely located below the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173, that is, the first partition 914 of the active layer is a certain distance away from the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173. The first active layer partition 914 is protected and isolated from the air, thereby preventing the Al-containing quantum well from being directly exposed to the air and causing oxidation failure.

[0157] A passivation layer 918 is grown on the first partition 917 of the waveguide layer. The passivation layer 918 is made of SiO 2 and has the functions of preventing oxidation and waterproofing, thereby protecting the laser chip 900 .

[0158] Figure 15 shows a cross-sectional structural diagram of a transition region in a laser chip according to some embodiments of the present disclosure. Figure 15 is a cross-sectional view taken along the Y direction shown in FIG11 , at the location of the first connecting portion 924a in the transition region 920. As shown in FIG15 , the transition region 920 may include, from bottom to top, a substrate 922, a second active layer subregion 923, a second waveguide layer subregion 924, and a passivation layer 925.

[0159] In some embodiments, when growing the laser chip 900 , in order to simplify the growth process, a first electrode layer is plated on the bottom surface of the laser chip 900 . The first electrode layer covers the light field transmission direction. Therefore, a first electrode layer 921 is also formed under the substrate 922 .

[0160] The transition region 920 does not need to inject current, and therefore, no second electrode layer is plated on the passivation layer 925 .

[0161] The second active layer subregion 923 is the active layer of the transition region 920. The second waveguide layer subregion 924 is the waveguide layer of the transition region 920. Since no current needs to be injected into the transition region 920, it does not truly constitute an active layer. Instead, the active layer is uniformly grown during the growth process of the laser chip 900. The active layer of the laser chip 900 is then divided along the light field transmission direction into a first active layer subregion 914 corresponding to the light-emitting region 910, a second active layer subregion 923 corresponding to the transition region 920, and a third active layer subregion corresponding to the electro-absorption modulation region 930.

[0162] The second waveguide layer partition 924 can be divided into a first connecting portion 924a and a second connecting portion 924b. The first connecting portion 924a and the second connecting portion 924b are divided by etching depth. The first connecting portion 924a can adopt a shallow etched ridge waveguide structure, while the second connecting portion 924b can adopt a deep etched ridge waveguide structure.

[0163] It can be understood that the substrate 922 and the second active layer subregion 923 are common to the first connecting portion 924a and the second connecting portion 924b. The only difference between the first connecting portion 924a and the second connecting portion 924b lies in the second waveguide layer subregion 924. The second waveguide layer subregion 924 corresponding to the first connecting portion 924a is a shallow-etched ridge waveguide. The second waveguide layer subregion 924 corresponding to the second connecting portion 924b is a deep-etched ridge waveguide junction. In other words, the second waveguide layer subregion 924 is divided into the first connecting portion 924a and the second connecting portion 924b along the light field transmission direction based on the etching depth. This is equivalent to the transition region 920 being divided into the first connecting portion 924a and the second connecting portion 924b at the waveguide layer second subregion 924.

[0164] The first connection portion 924a may include a ridge structure 9241a, a third ridge waveguide trench 9242a, and a fourth ridge waveguide trench 9243a respectively provided on both sides of the ridge structure 9241a.

[0165] The first connecting portion 924a can employ a shallowly etched ridge waveguide structure. Specifically, the third ridge waveguide trench 9242a and the fourth ridge waveguide trench 9243a in the first connecting portion 924a are etched downward to a depth that does not exceed the depth of the second active layer sub-area 923. Thus, the second active layer sub-area 923 is located below the third ridge waveguide trench 9242a and the fourth ridge waveguide trench 9243a. The third ridge waveguide trench 9242a and the fourth ridge waveguide trench 9243a are still some distance away from the third ridge waveguide trench 9242a and the fourth ridge waveguide trench 9243a.

[0166] The third ridge waveguide groove 9242a and the fourth ridge waveguide groove 9243a can be set to be rectangular and respectively provided on both sides of the ridge structure 9241a.

[0167] The first connecting portion 924 a adopts a shallow etched ridge waveguide structure, and thus has continuity with the light emitting region 910 in terms of etching depth.

[0168] FIG16 is a second cross-sectional structural diagram of a transition region in a laser chip provided according to some embodiments of the present disclosure. The structure shown in FIG16 is obtained by cross-sectioning the gradient structure in the second connecting portion 924b of the transition region 920 along the Y direction indicated in FIG11 . In the second connecting portion 924b, the fifth ridge waveguide groove 9242b may include a first gradient portion 9245b and a first non-gradient portion 9244b. In the second connecting portion 924b, the sixth ridge waveguide groove 9243b may include a second gradient portion 9247b and a second non-gradient portion 9246b. The first gradient portion 9245b and the second gradient portion 9247b constitute the gradient structure in the second connecting portion 924b. That is, the second connecting portion 924b has a gradient structure.

[0169] As shown in FIG16 , the second connecting portion 924b can employ a deep-etched ridge waveguide structure. Specifically, the fifth ridge waveguide groove 9242b and the sixth ridge waveguide groove 9243b in the second connecting portion 924b are etched downward to a depth exceeding the depth of the active layer second sub-segment 923. In the second connecting portion 924b, the active layer second sub-segment 923 is interrupted by the fifth ridge waveguide groove 9242b and the sixth ridge waveguide groove 9243b. For example, the active layer second sub-segment 923 is divided into three sections by the fifth ridge waveguide groove 9242b and the sixth ridge waveguide groove 9243b, respectively.

[0170] The second connecting portion 924b utilizes a deep-etched ridge waveguide structure, ensuring continuity in etch depth with the electro-absorption modulation region 930. Furthermore, the second connecting portion 924b includes a gradient structure comprising a first gradient portion 9245b and a second gradient portion 9247b. By providing the first and second gradient portions 9245b and 9247b, a smooth transition of the light field patterns between the light-emitting region 910 and the electro-absorption modulation region 930 can be achieved, thereby matching the light field patterns between the light-emitting region 910 and the electro-absorption modulation region 930 and improving the coupling efficiency between the light-emitting region 910 and the electro-absorption modulation region 930.

[0171] Figure 17 illustrates a cross-sectional view of the electro-absorption modulation region in a laser chip according to some embodiments of the present disclosure. A cross-section of the electro-absorption modulation region 930 along the Y direction indicated in FIG11 yields the structure shown in FIG17 . As shown in FIG17 , the electro-absorption modulation region 930 comprises, from bottom to top, a first electrode layer 931, a substrate 932, a third active layer section 933, a third waveguide layer section 934, a passivation layer 935, and a modulation electrode region 936. The third active layer section 933 constitutes the active layer of the electro-absorption modulation region 930, and the third waveguide layer section 934 constitutes the waveguide layer of the electro-absorption modulation region 930.

[0172] The first electrode layer 931 can be an N-type electrode layer. The modulation electrode region 936 can be a P-type electrode layer. The first electrode layer 931 and the modulation electrode region 936 can provide a reverse bias voltage and a modulation current to the electro-absorption modulation region 930. The light emitted by the light-emitting region 910 has parameters such as phase, intensity, and frequency. Under the action of the reverse bias voltage, one of these parameters changes according to the modulation current signal, thereby modulating the parameter, such as achieving intensity modulation.

[0173] In the present disclosure, the electro-absorption modulation region 930 adopts a deep-etched ridge waveguide structure to improve both the modulation efficiency and the modulation rate.

[0174] For example, the third subregion 934 of the waveguide layer can employ a deeply etched ridge waveguide structure. The ridge waveguide at the second connection portion of the third subregion 934 of the waveguide layer includes a ridge structure 9341, and a seventh ridge waveguide trench 9342 and an eighth ridge waveguide trench 9343 disposed on either side of the ridge structure 9341. The etching depths of the seventh and eighth ridge waveguide trenches 9342 and 9343 exceed the depth of the third subregion 933 of the active layer. The third subregion 933 of the active layer is interrupted by the seventh and eighth ridge waveguide trenches 9342 and 9343.

[0175] In this disclosure, to protect the Al-containing quantum well structure in the light-emitting region 910, the light-emitting region 910 utilizes a shallow-etched ridge waveguide structure. To improve the modulation rate and efficiency of the electro-absorption modulation region 930, the electro-absorption modulation region 930 utilizes a deep-etched ridge waveguide structure. To match the light field modes of the light-emitting region 910 and the electro-absorption modulation region 930, a transition region 920 is provided between the two regions. The second subregion 924 of the waveguide layer in the transition region 920 is divided into a first connecting portion 924a and a second connecting portion 924b along the light field transmission direction. The first connecting portion 924a utilizes a shallow-etched ridge waveguide structure, maintaining continuity with the light-emitting region 910 in terms of etch depth. The second connecting portion 924b utilizes a deep-etched ridge waveguide structure, maintaining continuity with the electro-absorption modulation region 930 in terms of etch depth. Furthermore, the second connecting portion 924b has a gradient structure comprising a first gradient portion 9245b and a second gradient portion 9247b. By providing the first gradual transition portion 9245b and the second gradual transition portion 9247b, a smooth transition of the light field mode between the light-emitting region 910 and the electro-absorption modulation region 930 can be achieved, thereby matching the light field pattern between the light-emitting region 910 and the electro-absorption modulation region 930, and thereby improving the coupling efficiency between the light-emitting region 910 and the electro-absorption modulation region 930. For example, the first connecting portion 924a and the ridge waveguide in the light-emitting region 910 are both etched to a depth of H1. The second connecting portion 924b and the electro-absorption modulation region 930 are both etched to a depth of H2.

[0176] In the present disclosure, the second connecting portion 924b and the electro-absorption modulation region 930 adopt a deep etched ridge waveguide structure. For the deep etched ridge waveguide structure, if there is no special design, the corresponding second electrode layer will be covered along the first ridge waveguide groove and the second ridge waveguide groove corresponding to the deep etched ridge waveguide. This causes the second electrode layer to be closer to the first electrode layer, resulting in a larger parasitic capacitance and reducing the bandwidth performance. To this end, a low dielectric constant medium can be filled in the first ridge waveguide groove and the second ridge waveguide groove corresponding to the deep etched ridge waveguide to avoid introducing a large parasitic capacitance. The metal on both sides of the first ridge waveguide groove and the second ridge waveguide groove can also be suspended on the top surface of the first ridge waveguide groove and the second ridge waveguide groove corresponding to the deep etched ridge waveguide through an air bridge or organic matter, which can also avoid introducing a large parasitic capacitance.

[0177] Figure 18 is a schematic diagram of the exploded structure of a laser chip according to some embodiments of the present disclosure. As shown in Figure 18 , the upper surface of the laser chip 900 is formed with a light-emitting electrode region 919 of the light-emitting region 910 and a modulation electrode region 936 of the electro-absorption modulation region 930.

[0178] By decomposing the light-emitting electrode region 919 and the modulation electrode region 936 , the waveguide layer of the laser chip 900 can be seen.

[0179] Along the optical field transmission direction, the waveguide layer of the laser chip 900 is divided into a first waveguide layer sub-area 917 , a second waveguide layer sub-area 924 , and a third waveguide layer sub-area 934 .

[0180] Figure 19 illustrates a partial structural diagram of a laser chip provided according to some embodiments of the present disclosure. Figure 19 illustrates the waveguide layer structure of laser chip 900. As shown in Figure 19, the ridge structures within the first waveguide layer subsection 917, the second waveguide layer subsection 924, and the third waveguide layer subsection 934 constitute the complete ridge structure of laser chip 900. The complete ridge structure of laser chip 900 is a ridge-stripe structure.

[0181] The first ridge waveguide trenches in each of the first waveguide layer section 917, the second waveguide layer section 924, and the third waveguide layer section 934 constitute a complete first ridge waveguide trench of the laser chip 900. The complete first ridge waveguide trench of the laser chip 900 is configured as a continuous trench.

[0182] The second ridge waveguide trenches in each of the first waveguide layer section 917, the second waveguide layer section 924, and the third waveguide layer section 934 constitute a complete second ridge waveguide trench of the laser chip 900. The complete second ridge waveguide trench of the laser chip 900 is configured as a continuous trench.

[0183] The waveguide structure in the light emitting region 910 includes a ridge structure 9171 and a first ridge waveguide trench 9172 and a second ridge waveguide trench 9173 disposed on both sides of the ridge structure 9171 .

[0184] The waveguide structure of the electro-absorption modulation region 930 includes a ridge structure 9341 and a seventh ridge waveguide trench 9342 and an eighth ridge waveguide trench 9343 disposed on both sides of the ridge structure 9341 .

[0185] The second subarea 924 of the waveguide layer in the transition region 920 includes a first connecting portion 924a and a second connecting portion 924b.

[0186] The first connection portion 924a may include a ridge structure 9241a, a third ridge waveguide trench 9242a, and a fourth ridge waveguide trench 9243a respectively provided on both sides of the ridge structure 9241a.

[0187] The first connection portion 924a may adopt a shallow etched ridge waveguide structure, that is, the etching depth of the third ridge waveguide groove 9242a and the fourth ridge waveguide groove 9243a in the first connection portion 924a does not exceed the depth of the second partition 923 of the active layer.

[0188] The second connection portion 924b includes a ridge structure 9241b, a fifth ridge waveguide trench 9242b, and a sixth ridge waveguide trench 9243b respectively provided on both sides of the ridge structure 9241b.

[0189] The second connecting portion 924b adopts a deep-etched ridge waveguide structure, that is, the fifth ridge waveguide groove 9242b and the sixth ridge waveguide groove 9243b in the second connecting portion 924b are etched downward to a depth exceeding the depth of the active layer in the transition region 920 .

[0190] In the second connecting portion 924b, the fifth ridge waveguide trench 9242b may include a first gradual transition portion 9245b and a first non-gradual transition portion 9244b. The sixth ridge waveguide trench 9243b may include a second gradual transition portion 9247b and a second non-gradual transition portion 9246b. The first gradual transition portion 9245b and the second gradual transition portion 9247b constitute the gradual transition structure in the second connecting portion 924b.

[0191] The first gradual transition portion 9245b has a first sidewall 92451. The second gradual transition portion 9247b has a second sidewall 92471. Along the direction from the first connecting portion 924a to the second connecting portion 924b, the first sidewall 92451 and the second sidewall 92471 can gradually move closer to the ridge structure 9241b. The width of the semiconductor material enclosed by the first side wall 92451 and the ridge structure 9241b gradually decreases, and the width of the semiconductor material enclosed by the second side wall 92471 and the ridge structure 9241b gradually decreases, and the light field pattern spot emitted by the light-emitting area 910 gradually decreases. The light field pattern spot transmitted by the ridge structure 9241a and the semiconductor material on both sides of the ridge structure 9241a are gradually gathered into the ridge structure 9241b, thereby realizing a smooth transition of the light field mode between the light-emitting area 910 and the electro-absorption modulation area 930, so as to match the light field modes of the light-emitting area 910 and the electro-absorption modulation area 930, avoiding the formation of a light field mode mutation interface between the shallowly etched ridge waveguide structure and the deeply etched ridge waveguide structure, thereby avoiding light field loss and reflection, and thereby improving the coupling efficiency between the light-emitting area 910 and the electro-absorption modulation area 930.

[0192] Figure 20 is a schematic diagram of the etched zoning of the waveguide layer in a laser chip according to some embodiments of the present disclosure. As shown in Figure 20, the waveguide layer of laser chip 900 has lateral etch depth zones. The boundary between the first connecting portion 924a and the second connecting portion 924b in the waveguide layer of laser chip 900 serves as the watershed for the etch depth zones. From the boundary between the first connecting portion 924a and the second connecting portion 924b toward the light-emitting region 910, the etch depth zones are shallow. From the boundary between the first connecting portion 924a and the second connecting portion 924b toward the electro-absorption modulation region 930, the etch depth zones are deep. That is, the shallow etch zone is to the right of the watershed, while the deep etch zone is to the left of the watershed. Therefore, the ridge waveguide structures in the first connecting portion 924a and the light-emitting region 910 are both shallow etched ridge waveguide structures. The ridge waveguide structures in the second connecting portion 924b and the electro-absorption modulation region 930 are both deep etched ridge waveguide structures.

[0193] In the light emitting region 910 , the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173 are etched downward to a depth that does not exceed the depth of the first partition 914 of the active layer, so as to protect the Al-containing quantum well structure.

[0194] The waveguide structure of the transition region 920, namely the second subregion 924 of the waveguide layer, includes a first connecting portion 924a and a second connecting portion 924b. The third ridge waveguide trench 9242a and the fourth ridge waveguide trench 9243a in the first connecting portion 924a are etched downward to a depth that does not exceed the depth of the second subregion 923 of the active layer. The fifth ridge waveguide trench 9242b and the sixth ridge waveguide trench 9243b in the second connecting portion 924b are etched downward to a depth that exceeds the depth of the active layer in the transition region 920.

[0195] In the second connecting portion 924b, the fifth ridge waveguide trench 9242b may include a first gradual transition portion 9245b and a first non-gradual transition portion 9244b; and the sixth ridge waveguide trench 9243b may include a second gradual transition portion 9247b and a second non-gradual transition portion 9246b. The first gradual transition portion 9245b and the second gradual transition portion 9247b constitute the gradual transition structure in the second connecting portion 924b.

[0196] By gradually moving the first side wall 92451 and the second side wall 92471 in the gradient structure closer to the ridge structure 9241b, a smooth transition of the light field mode between the light-emitting area 910 and the electro-absorption modulation area 930 can be achieved, thereby matching the light field mode spots between the light-emitting area 910 and the electro-absorption modulation area 930, and thereby improving the coupling efficiency between the light-emitting area 910 and the electro-absorption modulation area 930.

[0197] In the electro-absorption modulation region 930 , the seventh ridge waveguide groove 9342 and the eighth ridge waveguide groove 9343 are etched downward to a depth exceeding the depth of the third partition 933 of the active layer, so as to improve the modulation rate and modulation efficiency.

[0198] In the present disclosure, the light-emitting region 910 is a shallowly etched ridge waveguide structure, resulting in a larger light field pattern from the light-emitting region 910. The ridge structure 9171 of the light-emitting region 910 can have a larger ridge width at the light-emitting end to match the larger light field pattern from the light-emitting region 910 and increase the emission power. The ridge structure width corresponding to the light-input end of the electro-absorption modulation region 930 can be smaller to reduce junction capacitance and thereby increase the modulation rate. To achieve a transition and gradual change in ridge structure width, the width of the ridge structure 9241a corresponding to the first connecting portion 924a in the transition region 920 can be equal to the width of the ridge structure 9171 of the light-emitting region 910, thereby connecting to the ridge width of the light-emitting region 910. The width of the ridge structure 9241b corresponding to the second connecting portion 924b in the transition region 920 gradually decreases toward the electro-absorption modulation region 930 until it reaches the same width as the ridge structure 9341 of the electro-absorption modulation region 930, thereby connecting to the ridge width of the electro-absorption modulation region 910. By gradually changing the ridge width of the transition zone 920 , a smooth transition of the ridge width from the light-emitting zone 910 to the electro-absorption modulation zone 930 is achieved.

[0199] Figure 21 is a cross-sectional view of the light-emitting region of a laser chip according to some embodiments of the present disclosure. As shown in Figure 21, the ridge waveguide in the light-emitting region 910 uses a shallowly etched ridge waveguide structure to protect the Al-containing quantum well structure.

[0200] In the light emitting area 910 , the etching depth of the first ridge waveguide groove 9172 and the second ridge waveguide groove 9173 does not exceed the depth of the first partition 914 of the active layer.

[0201] Figure 22 illustrates a cross-sectional structure of a transition region in a laser chip according to some embodiments of the present disclosure. As shown in Figure 22, the waveguide structure of the transition region 920, namely, the second subregion 924 of the waveguide layer, includes a first connecting portion 924a and a second connecting portion 924b. These first and second connecting portions 924a and 924b are arranged sequentially along the direction of light field transmission. The first connecting portion 924a is located adjacent to the light-emitting region 910. The second connecting portion 924b is located adjacent to the electro-absorption modulation region 930. The first connecting portion 924a and the light-emitting region 910 utilize the same shallow-etched ridge waveguide structure.

[0202] In the second connecting portion 924b, the fifth ridge waveguide trench 9242b may include a first gradual transition portion 9245b and a first non-gradual transition portion 9244b; and the sixth ridge waveguide trench 9243b may include a second gradual transition portion 9247b and a second non-gradual transition portion 9246b. The first gradual transition portion 9245b and the second gradual transition portion 9247b constitute the gradual transition structure in the second connecting portion 924b.

[0203] By gradually moving the first side wall 92451 and the second side wall 92471 in the gradient structure closer to the ridge structure 9241b, a smooth transition of the light field mode between the light-emitting area 910 and the electro-absorption modulation area 930 can be achieved, thereby matching the light field mode spots between the light-emitting area 910 and the electro-absorption modulation area 930, and thereby improving the coupling efficiency between the light-emitting area 910 and the electro-absorption modulation area 930.

[0204] Figure 23 is a cross-sectional view of an electro-absorption modulation region in a laser chip according to some embodiments of the present disclosure. As shown in Figure 23, to improve the modulation rate and modulation efficiency of the laser chip, the electro-absorption modulation region 930 adopts a deep-etched ridge waveguide structure.

[0205] In the electro-absorption modulation region 930 , the seventh ridge waveguide trench 9342 and the eighth ridge waveguide trench 9343 are etched downward to a depth exceeding the depth of the third partition 933 of the active layer.

[0206] In the present disclosure, the method for preparing the laser chip 900 may include:

[0207] Growth substrate.

[0208] The active layer grows upward along the substrate surface.

[0209] A waveguide layer is grown upward along the surface of the active layer, and the waveguide layer is etched to form a ridge structure and ridge waveguide grooves located on both sides of the ridge structure. When etching the waveguide layer, etching is performed according to a first waveguide layer partition, a second waveguide layer partition, and a third waveguide layer partition. The ridge waveguide grooves located on both sides of the ridge structure in the first waveguide layer partition are etched downward to a depth that does not exceed the depth of the active layer. The second waveguide layer partition includes a first connecting portion and a second connecting portion along the light field transmission direction. The ridge waveguide grooves located on both sides of the ridge structure in the first connecting portion are etched downward to a depth that does not exceed the depth of the active layer, and the ridge waveguide grooves located on both sides of the ridge structure in the second connecting portion are etched downward to a depth that exceeds the depth of the active layer. The ridge waveguide grooves located on both sides of the ridge structure in the third waveguide layer partition are etched downward to a depth that exceeds the depth of the active layer.

[0210] The ridge waveguide groove located on one side of the ridge structure in the second connecting portion is etched toward one end of the first connecting portion to form a first gradient portion, and the ridge waveguide groove located on the other side of the ridge structure is etched toward one end of the first connecting portion to form a second gradient portion. The side walls of the first gradient portion and the second gradient portion close to the ridge structure gradually move closer to the ridge structure.

[0211] A first electrode layer is deposited below the substrate, and a second electrode layer is deposited above the waveguide layer.

[0212] In some embodiments, the active layer vertically corresponding to the first partition of the waveguide layer is the first partition of the active layer; the active layer vertically corresponding to the second partition of the waveguide layer is the second partition of the active layer; and the active layer vertically corresponding to the third partition of the waveguide layer is the third partition of the active layer.

[0213] In some embodiments, the ridge waveguide of the first subregion 917 of the waveguide layer includes a ridge structure 9171, a first ridge waveguide trench 9172, and a second ridge waveguide trench 9173 disposed on both sides of the ridge structure 9171. The etching depth of the first ridge waveguide trench 9172 and the second ridge waveguide trench 9173 does not exceed the depth of the first subregion of the active layer.

[0214] The ridge waveguide in the second connection portion of the third subregion 934 of the waveguide layer includes a ridge structure 9341, and a seventh ridge waveguide trench 9342 and an eighth ridge waveguide trench 9343 disposed on either side of the ridge structure 9341. The etching depth of the seventh ridge waveguide trench 9342 and the eighth ridge waveguide trench 9343 exceeds the depth of the third subregion 933 of the active layer.

[0215] The first connection portion 924a may include a ridge structure 9241a, a third ridge waveguide trench 9242a, and a fourth ridge waveguide trench 9243a respectively provided on both sides of the ridge structure 9241a.

[0216] The second connection portion 924b includes a ridge structure 9241b, a fifth ridge waveguide trench 9242b, and a sixth ridge waveguide trench 9243b respectively provided on both sides of the ridge structure 9241b.

[0217] The first connecting portion 924a adopts a shallow etched ridge waveguide structure, and the downward etching depth of the third ridge waveguide groove 9242a and the fourth ridge waveguide groove 9243a does not exceed the depth of the corresponding second partition of the active layer.

[0218] The second connecting portion 924b adopts a deep-etched ridge waveguide structure, and the fifth ridge waveguide groove 9242b and the sixth ridge waveguide groove 9243b are etched downward to a depth exceeding the depth of the corresponding second partition of the active layer.

[0219] In some embodiments, a grating layer is formed by etching between the first sub-region of the active layer and the first sub-region of the waveguide layer.

[0220] In some embodiments, when etching the ridge structure, the width of the ridge structure corresponding to the light output end of the first partition of the waveguide layer is greater than the width of the ridge structure corresponding to the light input end of the third partition of the waveguide layer.

[0221] The width of the ridge structure corresponding to one end of the second partition of the waveguide layer is the same as the width of the ridge structure corresponding to the light output end of the first partition of the waveguide layer, and the width of the ridge structure corresponding to the other end gradually decreases toward the light input end of the third partition of the waveguide layer.

[0222] In the present disclosure, a laser chip includes a light-emitting region, a transition region, and an electro-absorption modulation region, arranged in sequence. The ridge waveguide structure in the light-emitting region utilizes a shallowly etched ridge waveguide structure to protect the Al-containing quantum well structure from air oxidation. To improve the modulation rate and modulation efficiency of the laser chip, the electro-absorption modulation region utilizes a deeply etched ridge waveguide structure. Due to the characteristics of deep and shallow etching, the light field mode spot emitted by the light-emitting region is larger, while the light field mode spot of the electro-absorption modulation region is smaller. This results in a mismatch between the light field modes of the light-emitting region and the electro-absorption modulation region, thereby reducing the coupling efficiency between the two regions. To this end, the waveguide in the transition region is divided into a first connecting portion and a second connecting portion along the direction of light field transmission. The first connecting portion utilizes a shallowly etched ridge waveguide structure, maintaining continuity with the light-emitting region in terms of etching depth. The second connecting portion utilizes a deeply etched ridge waveguide structure, maintaining continuity with the electro-absorption modulation region in terms of etching depth. The second connecting portion also has a gradient structure, comprising a first gradient portion and a second gradient portion. By gradually bringing the first side wall and the second side wall in the gradient structure closer to the ridge structure, a smooth transition of the light field mode between the light-emitting area and the electro-absorption modulation area can be achieved, thereby matching the light field mode spots between the light-emitting area and the electro-absorption modulation area, avoiding light field back reflection and loss, and thus improving the coupling efficiency between the light-emitting area and the electro-absorption modulation area.

[0223] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present disclosure should be included within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A laser chip, characterized in that: From bottom to top, this includes: a first electrode layer; The active layer includes a first active layer partition, a second active layer partition, and a third active layer partition along the light field transmission direction; The waveguide layer, along the direction of light field transmission, includes: The first partition of the waveguide layer is stacked with the first partition of the active layer, and the first partition of the waveguide layer includes a ridge structure, and a first ridge waveguide groove and a second ridge waveguide groove provided on both sides of the ridge structure; the etching depth of the first ridge waveguide groove and the second ridge waveguide groove does not exceed the depth of the first partition of the active layer; The second partition of the waveguide layer is stacked with the second partition of the active layer. Along the light field transmission direction, the second partition of the waveguide layer includes a first connecting portion and a second connecting portion. The first connecting portion includes a ridge structure, a third ridge waveguide groove and a fourth ridge waveguide groove provided on both sides of the ridge structure. The second connecting portion includes a ridge structure, a fifth ridge waveguide groove and a sixth ridge waveguide groove provided on both sides of the ridge structure. The etching depth of the third ridge waveguide groove and the fourth ridge waveguide groove does not exceed the depth of the second partition of the active layer, and the etching depth of the fifth ridge waveguide groove and the sixth ridge waveguide groove exceeds the depth of the second partition of the active layer. The fifth ridge waveguide groove includes a first gradual transition portion, and the sixth ridge waveguide groove includes a second gradual transition portion. The sidewalls of the first gradual transition portion and the second gradual transition portion close to the ridge structure gradually move closer to the ridge structure. The third subregion of the waveguide layer is stacked with the third subregion of the active layer, and the third subregion of the waveguide layer includes a ridge structure, and a seventh ridge waveguide groove and an eighth ridge waveguide groove provided on both sides of the ridge structure; the etching depth of the seventh ridge waveguide groove and the eighth ridge waveguide groove exceeds the depth of the third subregion of the active layer; The second electrode layer includes a light-emitting electrode area and a modulation electrode area; the first electrode layer and the light-emitting electrode area provide carriers to the first partition of the active layer to emit light; the first electrode layer and the modulation electrode area provide modulation current to the third partition of the active layer to modulate the light.

2. The laser chip according to claim 1, characterized in that The ridge structures of the first partition of the waveguide layer, the second partition of the waveguide layer, and the third partition of the waveguide layer are continuous; the width of the ridge structure corresponding to the light output end of the first partition of the waveguide layer is greater than the width of the ridge structure corresponding to the light input end of the third partition of the waveguide layer; The width of the ridge structure corresponding to one end of the second partition of the waveguide layer is the same as the width of the ridge structure corresponding to the light output end of the first partition of the waveguide layer, and the width of the ridge structure corresponding to the other end gradually decreases toward the third partition of the waveguide layer.

3. The laser chip according to claim 1, wherein The first gradient portion has a first sidewall, and the second gradient portion has a second sidewall; along a direction from the first connecting portion to the second connecting portion, the first sidewall and the second sidewall gradually approach the ridge structure; the maximum distance between the first sidewall and the second sidewall is greater than a size of a light field mode spot emitted by the first partition of the waveguide layer, so that the light field mode spot emitted by the first partition of the waveguide layer is transmitted between the first sidewall and the second sidewall.

4. The laser chip according to claim 1, wherein: The fifth ridge waveguide trench includes a first non-gradually transitioned portion and the first gradually transitioned portion, and the sixth ridge waveguide trench includes a second non-gradually transitioned portion and the second gradually transitioned portion; The surface of the closed area enclosed by the first gradient portion and the first non-gradient portion is lower than the surface of the third ridge waveguide groove; The surface of the closed area enclosed by the second gradient portion and the second non-gradient portion is lower than the surface of the fourth ridge waveguide groove; The surface of the closed area enclosed by the first gradient portion and the first non-gradient portion is lower than the surface of the remaining area in the fifth ridge waveguide groove; A surface of a closed area enclosed by the second gradient portion and the second non-gradient portion is lower than surfaces of other areas in the sixth ridge waveguide groove.

5. The laser chip according to claim 1, wherein: The first connecting portion is connected to the first partition of the waveguide layer, and the second connecting portion is connected to the third partition of the waveguide layer; The first connecting portion and the first partition of the waveguide layer respectively adopt a shallow etched ridge waveguide structure, and the second connecting portion and the third partition of the waveguide layer respectively adopt a deep etched ridge waveguide structure.

6. The laser chip according to claim 1, characterized in that A grating layer is provided between the first subregion of the active layer and the first subregion of the waveguide layer.

7. The laser chip according to claim 1, characterized in that The growth material of the first subregion of the active layer includes AlInGaAs.

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