Optical module, laser epitaxial wafer, and method for preparing laser epitaxial wafer

Abstract

An optical module (200), a laser epitaxial wafer (410a), and a method for preparing the laser epitaxial wafer (410a). The optical module (200) comprises a laser chip (410), and the laser chip (410) is formed by etching the laser epitaxial wafer (410a). The laser epitaxial wafer (410a) comprises an N-type InP layer (411), a light spot expansion layer (412), an N-type confinement layer (413), and a quantum well layer (414) which are sequentially stacked. The light spot expansion layer (412) comprises a first InP layer (4121a), a first InGaAsP layer (4122a), a second InP layer (4121b), and a second InGaAsP layer (4122b) which are stacked from bottom to top, and the first InP layer (4121a) is located above the N-type InP layer (411). The refractive index of the first InGaAsP layer (4122a) is greater than the refractive index of the first InP layer (4121a), and the refractive index of the second InP layer (4121b) is less than the refractive index of the first InGaAsP layer (4122a). The refractive index of the second InGaAsP layer (4122b) is greater than the refractive index of the N-type confinement layer (413), and the refractive index of the second InGaAsP layer (4122b) is greater than the refractive index of the second InP layer (4121b), which helps reduce the loss of the laser chip (410).

Description

Optical module, laser epitaxial wafer and laser epitaxial wafer preparation method

[0001] This application claims priority to the application No. 202411376179.0 filed with the China Patent Office on September 29, 2024; the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the field of optical communication technology, in particular to an optical module, a laser epitaxial wafer and a laser epitaxial wafer preparation method. BACKGROUND

[0003] With the development of new business and application modes such as cloud computing, mobile Internet, video, etc., the development and progress of optical communication technology become increasingly important. In optical communication technology, optical modules are tools for converting optical and electrical signals, and are one of the key devices in optical communication equipment. With the development needs of optical communication technology, the transmission rate of optical modules is continuously increasing. In some optical modules, high-transmission-rate optical modules have higher integration density than low-transmission-rate optical modules, such as using multi-channel optical transceiver technology to realize the emission and reception of multi-wavelength optical signals of optical modules. SUMMARY

[0004] Some embodiments provide an optical module, comprising:

[0005] a circuit board;

[0006] an optical transmitting component electrically connected to the circuit board;

[0007] The optical transmitting component comprises:

[0008] a laser chip for generating an optical signal; the laser chip is formed by etching a laser epitaxial wafer;

[0009] The laser epitaxial wafer comprises:

[0010] an N-type InP layer;

[0011] an N-type confinement layer located above the N-type InP layer;

[0012] a quantum well layer located above the N-type confinement layer;

[0013] The N-type InP layer and the N-type confinement layer form a spot expansion layer therebetween, and the spot expansion layer comprises:

[0014] a first InP layer located above the N-type InP layer;

[0015] a first InGaAsP layer located above the first InP layer, the refractive index of the first InGaAsP layer being greater than the refractive index of the first InP layer;

[0016] a second InP layer located above the first InGaAsP layer, the second InP layer having a refractive index less than the refractive index of the first InGaAsP layer;

[0017] a second InGaAsP layer located above the second InP layer, the second InGaAsP layer being in contact with the top of the N-type confinement layer, the second InGaAsP layer having a refractive index greater than the refractive index of the N-type confinement layer and a refractive index greater than the refractive index of the second InP layer.

[0018] Some embodiments provide an optical module, comprising:

[0019] a circuit board;

[0020] a light emitting component electrically connected to the circuit board;

[0021] the light emitting component comprises: a laser chip for generating an optical signal; the laser chip is formed by etching a laser epitaxial wafer;

[0022] wherein the laser epitaxial wafer comprises:

[0023] an N-type InP layer;

[0024] an N-type confinement layer located above the N-type InP layer;

[0025] a quantum well layer located above the N-type confinement layer;

[0026] wherein a spot expansion layer is formed between the N-type InP layer and the N-type confinement layer, the spot expansion layer comprises:

[0027] an InP layer located above the N-type InP layer,

[0028] an InGaAsP layer located above the InP layer, the InGaAsP layer having a refractive index greater than the refractive index of the N-type InP layer and a refractive index greater than the refractive index of the InP layer.

[0029] Some embodiments provide a laser epitaxial wafer, comprising:

[0030] an N-type InP layer;

[0031] an N-type confinement layer located above the N-type InP layer;

[0032] a quantum well layer located above the N-type confinement layer;

[0033] wherein a spot expansion layer is formed between the N-type InP layer and the N-type confinement layer, the spot expansion layer comprises:

[0034] a first InP layer located above the N-type InP layer;

[0035] a first InGaAsP layer above the first InP layer, the first InGaAsP layer having a refractive index greater than a refractive index of the first InP layer;

[0036] a second InP layer above the first InGaAsP layer, the second InP layer having a refractive index less than a refractive index of the first InGaAsP layer;

[0037] a second InGaAsP layer above the second InP layer, the second InGaAsP layer being connected to the N-type confinement layer at a top portion, the second InGaAsP layer having a refractive index greater than a refractive index of the N-type confinement layer and a refractive index greater than a refractive index of the second InP layer.

[0038] Some embodiments provide a laser epitaxial wafer, comprising:

[0039] an N-type InP layer;

[0040] an N-type confinement layer above the N-type InP layer;

[0041] a quantum well layer above the N-type confinement layer;

[0042] wherein a spot expansion layer is formed between the N-type InP layer and the N-type confinement layer, the spot expansion layer comprising:

[0043] an InP layer above the N-type InP layer,

[0044] an InGaAsP layer above the InP layer, the InGaAsP layer having a refractive index greater than a refractive index of the N-type InP layer and a refractive index greater than a refractive index of the InP layer.

[0045] Some embodiments provide a method for manufacturing a laser epitaxial wafer, the laser epitaxial wafer being used for etching to form a laser chip, the method comprising:

[0046] forming an N-type InP layer on a substrate;

[0047] forming a spot expansion layer on the N-type InP layer, the spot expansion layer comprising, from bottom to top, a first InP layer, a first InGaAsP layer, a second InP layer, and a second InGaAsP layer; wherein the first InGaAsP layer has a refractive index greater than a refractive index of the first InP layer, the second InGaAsP layer has a refractive index greater than a refractive index of the second InP layer, and the first InGaAsP layer has a refractive index greater than a refractive index of the second InP layer;

[0048] forming an N-type confinement layer on the spot expansion layer, the N-type confinement layer having a refractive index less than a refractive index of the second InGaAsP layer;

[0049] A quantum well layer is formed on the N-type confinement layer. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the present disclosure, the drawings used in some embodiments of the present disclosure will be briefly introduced as follows. Obviously, the drawings in the following description are only some drawings of the embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art according to these drawings. In addition, the drawings in the following description can be regarded as schematic diagrams, and are not a limitation on the actual size of the product, the actual flow of the method, the actual timing of the signal, etc. involved in the embodiments of the present disclosure.

[0051] FIG. 1 is a partial architecture diagram of an optical communication system according to some embodiments;

[0052] FIG. 2 is a partial structure diagram of a host computer according to some embodiments;

[0053] FIG. 3 is a structure diagram of an optical module according to some embodiments;

[0054] FIG. 4 is an exploded view of an optical module according to some embodiments;

[0055] FIG. 5 is an exploded view of an optical transmitting component according to some embodiments;

[0056] FIG. 6 is a structure diagram of a laser assembly according to some embodiments;

[0057] FIG. 7 is a structure diagram of a laser epitaxial wafer according to some embodiments;

[0058] FIG. 8 is an enlarged view of a quantum well layer according to some embodiments;

[0059] FIG. 9 is a band gap width relationship diagram of a well in a quantum well layer according to some embodiments;

[0060] FIG. 10 is a gain comparison diagram of a quantum well layer according to some embodiments;

[0061] FIG. 11 is a partial view of a laser epitaxial wafer according to some embodiments;

[0062] FIG. 12a is a light field effect diagram of a laser epitaxial wafer according to some embodiments;

[0063] FIG. 12b is a light field effect diagram of another laser epitaxial wafer according to some embodiments;

[0064] FIG. 13 is a partial view of another laser epitaxial wafer according to some embodiments;

[0065] FIG. 14 is a flowchart of a laser epitaxial wafer preparation method according to some embodiments. DETAILED DESCRIPTION

[0066] Some embodiments of the present disclosure will be described in detail below with reference to the drawings. However, the described embodiments are only a part of the embodiments of the present disclosure, not all the embodiments. Based on the embodiments provided in the present disclosure, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present disclosure.

[0067] Unless otherwise required by the context, throughout the specification and claims, the term "comprising" is interpreted to mean "including, but not limited to"; the terms "first", "second", etc. are not used to denote or imply relative importance or an upper limit on the number; the term "multiple" means two or more; the term "connected" should be interpreted broadly, for example, "connected" can be fixed connection, or detachable connection, or integral, can be directly connected, or indirectly connected through an intermediate medium; the use of the terms "adapted to" or "configured to" means open and inclusive language, which does not exclude devices adapted to or configured to perform additional tasks or steps; the terms "parallel", "vertical", "same", "consistent", "flush" and the like are not limited to absolute mathematical theoretical relationship, but also include acceptable error range generated in practice, and also include differences based on the same design concept but due to manufacturing reasons.

[0068] In optical communication technology, in order to establish information transmission between information processing devices, information is loaded onto light, and the transmission of information is carried out by using the propagation speed of light. Such information-loaded light is optical signal. Optical signal can reduce the loss of optical power when transmitted in optical information transmission equipment, and realize long-distance transmission of optical signal. At the same time, the cost of optical information transmission equipment such as optical fiber is lower than that of electrical information transmission equipment such as copper wire. Therefore, optical communication technology can realize high-speed, long-distance and low-cost information transmission.

[0069] Information processing devices usually include optical network terminal (ONU), gateway, router, switch, mobile phone, computer, server, tablet computer, television and the like, and optical information transmission equipment usually includes optical fiber and optical waveguide and the like. The signal that can be recognized and processed by the information processing device is electrical signal, while the optical communication technology uses optical signal for transmission, which needs optical module to convert optical signal and electrical signal.

[0070] The optical module can realize mutual conversion between optical signals and electrical signals between the information processing device and the optical information transmission device. In some embodiments, at least one of the optical signal input end or the optical signal output end of the optical module is connected with an optical fiber, and at least one of the electrical signal input end or the electrical signal output end of the optical module is connected with an optical network terminal; a first optical signal from the optical fiber is transmitted to the optical module, the optical module 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, the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber.

[0071] Since the information transmission between multiple information processing devices can be realized through electrical signals, at least one of the multiple information processing devices needs to be directly connected with the optical module, without the need of directly connecting all the information processing devices with the optical module. Here, the information processing device directly connected with the optical module is also referred to as the host computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module is referred to as an optical port, and the electrical signal input end or the electrical signal output end of the optical module is referred to as an electrical port.

[0072] FIG. 1 is a partial structure diagram of an optical communication system according to some embodiments. As shown in FIG. 1, the optical communication system mainly includes a remote information processing device 1000, a local information processing device 2000, a host computer 100 of an optical module, an optical module 200, an optical fiber 101, and a network cable 103, wherein the optical fiber 101 belongs to an optical information transmission device, and the network cable 103 belongs to an electrical information transmission device.

[0073] In some embodiments, one end of the optical fiber 101 extends to the direction of the remote information processing device 1000, and the other end of the optical fiber 101 is connected with the optical module 200 through the optical port of the optical module 200. The optical signal can be totally reflected in the optical fiber 101, and the propagation of the optical signal in the totally reflected direction can almost maintain the original optical power. The optical signal is totally reflected in the optical fiber 101 for multiple times, so as to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance information transmission based on low power loss.

[0074] The optical communication system includes one or more optical fibers 101. In some embodiments, the optical fiber 101 is detachably connected with the optical module 200; in some embodiments, the optical fiber 101 is non-detachably connected with the optical module 200.

[0075] The host computer 100 is configured to provide a data signal to the optical module 200, or receive a data signal from the optical module 200, or monitor or control the working state of the optical module 200.

[0076] The host computer 100 includes a housing accommodating the optical module 200, and an optical module interface 102 disposed on the housing. The optical module 200 is inserted into the housing through the optical module interface 102, so that the host computer 100 establishes a unidirectional or bidirectional electrical signal connection with the optical module 200.

[0077] The host computer 100 further includes an external electrical interface that can access an electrical signal network. In some embodiments, the external electrical interface includes a Universal Serial Bus (USB) 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.

[0078] 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 through the network cable 103. In some embodiments, a third electrical signal emitted by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103, the host computer 100 generates a second electrical signal according to the third electrical signal, the second electrical signal from the host computer 100 is transmitted to the optical module 200, the optical module 200 converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber 101, and the second optical signal is transmitted in the optical fiber 101 to the remote information processing device 1000.

[0079] In some embodiments, the first optical signal from the remote information processing device 1000 propagates 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 according to the first electrical signal, and transmits the fourth electrical signal to the local information processing device 2000.

[0080] In some embodiments, the optical module is a tool for converting optical signals and electrical signals, and in the conversion process of the optical signals and the electrical signals, the information does not change, and the encoding or decoding method of the information changes.

[0081] The host computer 100 includes an Optical Line Terminal (OLT), an Optical Network Terminal (ONT), or a data center server, in addition to the optical network terminal.

[0082] Figure 2 is a partial structural diagram of a host computer according to some embodiments. In order to clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 only shows the structure of the host computer 100 related to the optical module 200. As shown in Figure 2, in some embodiments, the host computer 100 further comprises a PCB circuit board 105 arranged in the accommodation cavity, and a cage 106 arranged on the surface of the PCB circuit board 105; the optical module 200 is inserted into the cage 106 and fixed by the cage 106.

[0083] In some embodiments, the cage 106 is provided with a heat sink 107, which can dissipate heat for the optical module; in some embodiments, the heat sink 107 has a protruding structure such as fins to increase the heat dissipation area.

[0084] In some embodiments, the cage 106 is internally provided with an electrical connector configured to access the electrical port of the optical module 200.

[0085] In some embodiments, the optical module 200 is inserted into the cage 106 of the host computer 100, and the optical module 200 is fixed by the cage 106. The heat generated by the optical module 200 is conducted to the cage 106, and then diffused through the heat sink 107.

[0086] In some embodiments, the optical module 200 is inserted into the cage 106 of the host computer 100, and the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 and the host computer 100 establish electrical signal connection.

[0087] In some embodiments, the optical port of the optical module 200 is connected to the optical fiber 101, so that the optical module 200 and the optical fiber 101 establish optical signal connection.

[0088] Figure 3 is a structural diagram of an optical module according to some embodiments, and Figure 4 is an exploded view of an optical module according to some embodiments. As shown in Figures 3 and 4, in some embodiments, the optical module 200 comprises a shell comprising an upper shell 201 and a lower shell 202. The upper shell 201 covers the lower shell 202 to form two openings 203 and 204, one of which is an electrical port and the other of which is an optical port. In some embodiments, the shell forms one opening which is both an electrical port and an optical port.

[0089] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal material, which is beneficial to realize electromagnetic shielding and heat dissipation.

[0090] The assembly method of the upper shell 201 and the lower shell 202 facilitates the installation of the circuit board 300, the light emitting component 400, the light receiving component 500 and the like into the shell, and the shell can encapsulate and protect the above-mentioned devices.

[0091] The direction of the line connecting the two openings 203 and 204 can be consistent with the length direction of the optical module 200, or can be inconsistent with the length direction of the optical module 200. For example, the opening 203 is located at the end of the optical module 200 (the right end of FIG. 3), and the opening 204 is also located at the end of the optical module 200 (the left end of FIG. 3). Alternatively, the opening 203 is located at the end of the optical module 200, and the opening 204 is located at the side of the optical module 200.

[0092] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and arranged perpendicularly to the bottom plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the shell.

[0093] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and arranged perpendicularly to the bottom plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and arranged perpendicularly to the cover plate 2011, and the two upper side plates and the two lower side plates 2022 are combined to realize that the upper shell 201 covers the lower shell 202.

[0094] As shown in FIGS. 3 and 4, in some embodiments, the optical module includes a circuit board 300 arranged in the shell, and the circuit board 300 includes circuit traces, electronic components, and chips, etc. The electronic components and chips are connected according to the circuit design through the circuit traces to realize power supply, electrical signal transmission, and grounding functions. The electronic components can include capacitors, resistors, transistors, and metal oxide semiconductor field effect transistors (MOSFETs). The chips can include microcontroller units (MCUs), laser drive chips, transimpedance amplifiers (TIAs), limiting amplifiers (LAs), clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0095] In some embodiments, the circuit board comprises a rigid circuit board, which can also serve as a carrier due to its relatively hard material, such as the rigid circuit board can stably carry the 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.

[0096] In some embodiments, the circuit board further comprises a flexible circuit board, which can be used independently; or can be used in cooperation with the rigid circuit board.

[0097] In some embodiments, the circuit board further comprises a gold finger formed on the end surface thereof, and the gold finger is composed of a plurality of pins independent of each other.

[0098] In some embodiments, the gold finger 301 is arranged on the surface (such as the upper surface shown in FIG. 4) of one side of the circuit board 300; in some embodiments, the gold finger 301 is arranged on the surfaces of both upper and lower sides of the circuit board 300 to provide a larger number of pins to adapt to occasions requiring a large number of pins.

[0099] In some embodiments, the gold finger of the circuit board extends from the electrical port 203 and is inserted into the electrical connector of the host computer 100; the circuit board is inserted into the cage 106, and the gold finger 301 is in conduction with the electrical connector in the cage 106. The gold finger 301 is configured to establish electrical connection with the host computer, and can realize functions such as power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, data signal transmission, etc.

[0100] In some embodiments, the optical module 200 further comprises an unlocking component 600 located outside the shell thereof. The unlocking component 600 is configured to realize the 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.

[0101] For example, the unlocking component 600 is located outside the two lower side plates 2022 of the lower shell 202, and comprises a clamping component matched with the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the optical module 200 is fixed in the cage 106 by the clamping component of the unlocking component 600; when the unlocking component 600 is pulled, the clamping component of the unlocking component 600 moves accordingly, thereby changing the connection relationship between the clamping component and the host computer, to release the fixation between the optical module 200 and the host computer, so that the optical module 200 can be pulled out of the cage 106.

[0102] In some embodiments, the light emitting component 400 and the light receiving component 500 can be physically separated from the circuit board 300, and then electrically connected to the circuit board 300 through corresponding flexible circuit boards or electrical connectors, respectively.

[0103] In some embodiments, 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 distal to the golden fingers 301.

[0104] In some embodiments, at least one of the light emitting component 400 or the light receiving component 500 can be directly disposed on the circuit board 300. For example, at least one of the light emitting component 400 or the light receiving component 500 can be disposed on a surface of the circuit board 300 or a side of the circuit board 300.

[0105] In some embodiments, the light emitting component 400 can include a cavity, and the cavity is configured to house an electrical device for generating an emitted optical signal and an optical device for transmitting the emitted optical signal; wherein the electrical device includes a laser, etc., and the optical device includes a collimating lens, etc.

[0106] In some embodiments, the light receiving component 500 can include a cavity, and the cavity is configured to house an optical device for transmitting a received optical signal and an electrical device for converting the received optical signal; wherein the optical device includes a converging lens, etc., and the electrical device includes a photodetector, etc.

[0107] In some embodiments, the light emitting component 400 and the light receiving component 500 can share a cavity, such as a double-layered cavity, one layer for the light emitting component 400 and the other layer for the light receiving component 500.

[0108] In some embodiments, the light emitting component 400 and the light receiving component 500 can not share a cavity, and the light emitting component 400 and the light receiving component 500 are independent of each other, and the light emitting component 400 and the light receiving component 500 can be disposed on the same side of the circuit board 300. Of course, in the embodiments of the present disclosure, the light emitting component 400 and the light receiving component 500 can also be disposed on different sides of the circuit board 300.

[0109] In some embodiments, the light emitting component 400 can generate optical signals of multiple wavelengths. For example, the light emitting component 400 can generate a beam of optical signals including four wavelengths.

[0110] FIG. 5 is an exploded view of a light emitting component according to some embodiments. In some embodiments, as shown in FIG. 5, the light emitting component 400 includes a cavity 401, and a laser assembly 400a is disposed in the cavity 401. For example, one side wall of the cavity 401 has an opening for insertion of the circuit board 300, and the circuit board 300 inserted into the cavity is electrically connected to the laser assembly 400a.

[0111] In some embodiments, the light emitting component 400 includes a cover plate 402 covering the cavity 401.

[0112] In some embodiments, the light emitting component 400 can include a plurality of laser assemblies 400a arranged in an array. Each laser assembly 400a can include a substrate and a laser chip, and the laser chip can generate light signals of a wavelength, and the laser chip can be disposed on the substrate. For example, the light emitting component 400 can include four laser assemblies 400a arranged in an array.

[0113] In some embodiments, in order to ensure the coupling efficiency of the light signals generated by the laser assemblies 400a, a lens can be disposed on the output light path of the laser assemblies 400a, and the assembly precision of the lens is required to be high. In order to ensure the assembly precision of the lens, the lens is usually disposed on the output light path of the corresponding laser assembly 400a by means of active coupling.

[0114] FIG. 6 is a structural diagram of a laser assembly according to some embodiments. In some embodiments, as shown in FIG. 6, the laser assembly 400a can include a laser chip 410 and a substrate 420, and the laser chip 410 can be disposed on the substrate 420. The laser chip 410 can be formed by etching a laser epitaxial wafer.

[0115] FIG. 7 is a structural diagram of a laser epitaxial wafer according to some embodiments. In some embodiments, the laser epitaxial wafer 410a can include an N-type InP layer 411. The N-type InP layer 411 can be formed by growing an N-type InP semiconductor material. For example, the N-type InP layer 411 can be formed by growing an N-type InP semiconductor material on an N-type InP semiconductor material substrate.

[0116] In some embodiments, the laser epitaxial wafer 410a can include a spot expansion layer 412 located above the N-type InP layer 411. The spot expansion layer 412 can be used to expand the light field of the laser to an N region, which is an N-doped region of the laser. The spot expansion layer 412 can be formed by growing an N-type InP semiconductor material with a relatively large refractive index. For example, the spot expansion layer 412 can be formed by growing an N-type InGaAsP on the N-type InP layer 411.

[0117] In some embodiments, the laser epitaxial wafer 410a can include an N-type confinement layer 413 located above the spot expansion layer 412. The N-type confinement layer 413 can be formed by growing an N-type InP semiconductor material. For example, the N-type confinement layer 413 can be formed by growing an N-type InP semiconductor material on the spot expansion layer 412. The refractive index of the N-type confinement layer 413 is less than the refractive index of the spot expansion layer 412.

[0118] In some embodiments, the laser epitaxial wafer 410a can include a quantum well layer 414 that excites to generate light. The quantum well layer 414 includes multiple pairs of quantum wells, and the quantum well layer 414 is a multi-layer structure grown by alternating thin layers of different semiconductor materials. The multiple pairs of quantum wells include quantum wells with different band gap widths, i.e., the band gap widths of the quantum wells in the multiple pairs of quantum wells are not all the same. For example, the quantum well layer 414 includes quantum wells with different band gap widths, or the band gap widths of the quantum wells in the quantum well layer 414 are not all the same.

[0119] FIG. 8 is an enlarged view of a quantum well layer according to some embodiments, and FIG. 8 shows a detailed structure of a quantum well layer. In some embodiments, as shown in FIG. 8, the quantum well layer 414 includes a well 4141, a well 4142, a well 4143, a well 4144, and a well 4145, forming a quantum well layer 414 with 5 pairs of quantum wells; wherein the band gap widths of the wells in the 5 pairs of quantum wells are not all the same. For example, the 5 pairs of quantum wells include quantum wells with two different band gap widths, quantum wells with three different band gap widths, or quantum wells with four different band gap widths, etc. Of course, in some embodiments, the quantum well layer 414 is not limited to including 5 pairs of quantum wells, but can also include other numbers of pairs of quantum wells, such as 3 pairs of quantum wells, 6 pairs of quantum wells, etc.

[0120] FIG. 9 is a diagram of the relationship between the band gap widths of the wells in a quantum well layer according to some embodiments. In some embodiments, as shown in FIG. 9, the 5 pairs of quantum wells include quantum wells with two different band gap widths. Among them: the band gap widths of 3 pairs of quantum wells in the 5 pairs of quantum wells are the same, and this band gap width is denoted as a for convenience of description, and the band gap widths of the other 2 pairs of quantum wells are the same, and this band gap width is denoted as b. For example, the 5 pairs of quantum wells in the quantum well layer 414 include the well 4141, the well 4142, the well 4143, the well 4144, and the well 4145, and the band gap widths of three of the well 4141, the well 4142, the well 4143, the well 4144, and the well 4145 are a, and the band gap widths of the other two are b.

[0121] In some embodiments, the band gap widths of the well 4141, the well 4143, and the well 4145 are a, and the band gap widths of the well 4142 and the well 4144 are b. Of course, in some embodiments, the band gap widths of the well 4141, the well 4142, and the well 4143 are a, or the band gap widths of the well 4143, the well 4144, and the well 4145 are a, etc.

[0122] Figure 10 is a gain comparison diagram of a quantum well layer according to some embodiments, where curve 1 is a gain curve corresponding to the quantum well layer having different band gap widths of the wells, and curve 2 is a gain curve corresponding to the quantum well layer having the same band gap width of the wells. As shown in Figure 10, when the quantum well layer 414 has different band gap widths of the wells, the width of the gain spectrum of the quantum well layer 414 is increased, so that the quantum well layer 414 can support lasing at different temperatures, and the efficiency of the laser chip at different temperatures can be ensured.

[0123] In some embodiments, the laser epitaxial wafer 410a can include a P-type confinement layer 415 located above the quantum well layer 414. The P-type confinement layer 415 can be formed by growing P-type InP semiconductor material. For example, the P-type InP semiconductor material is grown above the quantum well layer 414 to form the P-type confinement layer 415. The P-type confinement layer 415 belongs to the P region of the laser, and the P region is the P-doped region of the laser.

[0124] In some embodiments, the laser epitaxial wafer 410a can include a P-type InP layer 416 located above the P-type confinement layer 415. The P-type InP layer 416 can be formed by growing P-type InP semiconductor material. For example, the P-type InP semiconductor material is grown above the P-type confinement layer 415 to form the P-type InP layer 416. An electrode can be formed above the P-type InP layer 416, and the P-type InP layer 416 supports the electrode, through which an electrical signal can be applied to the quantum well layer 414 and the like.

[0125] Since light has the characteristic of transmitting into a medium with relatively large refractive index, the light spot expansion layer 412 is provided below the N-type confinement layer 413, and the refractive index of the light spot expansion layer 412 is greater than that of the N-type confinement layer 413. The light generated by lasing of the quantum well layer 414 will expand in the direction of the light spot expansion layer 412, i.e., the light field of the laser epitaxial wafer 410a is expanded to the N-doped region. The absorption rate of light by the N-doped region is smaller than that by the P-doped region, and the light field of the laser epitaxial wafer 410a is expanded to the N-doped region, thereby reducing the loss of the light field in the P-doped region.

[0126] Figure 11 is a partial view of a laser epitaxial wafer according to some embodiments. In some embodiments, as shown in Figure 11, the light spot expansion layer 412 includes an InP layer 4121 and an InGaAsP layer 4122, the InGaAsP layer 4122 is located above the InP layer 4121, the refractive index of the InGaAsP layer 4122 is greater than that of the InP layer 4121, and the refractive index of the InGaAsP layer 4122 is greater than that of the N-type confinement layer 413. For example, the InP layer 4121 is located above the N-type InP layer 411, and the InGaAsP layer 4122 is located above the InP layer 4121.

[0127] The spot expansion layer 412 includes an InP layer 4121 and an InGaAsP layer 4122. The InGaAsP layer 4122 has a refractive index greater than that of the N-type confinement layer 413, so as to expand the light field of the laser epitaxial wafer 410a to the N-doped region. The InP layer 4121 has a refractive index less than that of the InGaAsP layer 4122, so as to reduce the excessive deviation of the light field of the laser epitaxial wafer 410a to the N-doped region, and to prevent the main peak of the light field of the laser epitaxial wafer 410a from deviating from the region of the quantum well layer 414.

[0128] In some embodiments, the thickness of the InGaAsP layer 4122b is greater than that of the InP layer 4121. For example, the thickness of the InGaAsP layer 4122b is twice that of the InP layer 4121. Of course, in some embodiments, the thickness of the InGaAsP layer 4122b is not limited to twice that of the InP layer 4121, and can be 1.5 times or 2.5 times that of the InP layer 4121. In this way, the performance of the spot expansion layer 412 in expanding the light field of the laser epitaxial wafer 410a to the N-doped region is ensured.

[0129] In some embodiments, the InP layer 4121 is formed by growing N-type InP material, and the InGaAsP layer 4122 is formed by growing N-type InGaAsP material. For example, the N-type InP material is grown on the N-type InP layer 411 to form the InP layer 4121, and the N-type InGaAsP material is grown on the InP layer 4121 to form the InGaAsP layer 4122.

[0130] In some embodiments, the spot expansion layer 412 includes multiple InGaAsP layers 4122 and multiple InP layers 4121, and the InGaAsP layers 4122 and the InP layers 4121 are arranged in an interlaced manner from top to bottom. The InGaAsP layer 4122 has a refractive index greater than that of the InP layer 4121. The use of the interlaced arrangement of the InGaAsP layer 4122 and the InP layer 4121 in the spot expansion layer 412 facilitates the expansion of the light field of the laser epitaxial wafer 410a to the N-doped region, and reduces the excessive deviation of the light field of the laser epitaxial wafer 410a to the N-doped region.

[0131] In some embodiments, the number of layers of the InGaAsP layer 4122 in the spot expansion layer 412 is greater than or equal to 2, and the number of layers of the InP layer 4121 in the spot expansion layer 412 is greater than or equal to 2. For example, the number of layers of the InGaAsP layer 4122 in the spot expansion layer 412 is 2 or 3, and the number of layers of the InP layer 4121 in the spot expansion layer 412 is 2 or 3.

[0132] In some embodiments, the number of layers of InGaAsP layer 4122 and the number of layers of InP layer 4121 in spot expansion layer 412 is less than or equal to 3. This satisfies the requirement of expanding the light field of laser epitaxial wafer 410a to the N-doped region, and effectively controls the complexity of preparing spot expansion layer 412.

[0133] FIG. 12a is a light field effect diagram of a laser epitaxial wafer according to some embodiments, which shows the light field distribution of a laser epitaxial wafer 410a without a spot expansion layer 412. As shown in FIG. 12a, the light field of laser epitaxial wafer 410a is mainly concentrated in quantum well layer 414, and the light field of laser epitaxial wafer 410a expands to both sides of quantum well layer 414, i.e., the light field of laser epitaxial wafer 410a expands to P-doped region and N-doped region with quantum well layer 414 as the center. The P-doped region has a relatively large light absorption rate, and the light field has a large loss in the P-doped region. When the loss of light in the P-doped region is too large, the output optical power of laser epitaxial wafer 410a will decrease.

[0134] FIG. 12b is a light field effect diagram of another laser epitaxial wafer according to some embodiments, which shows the light field distribution of a laser epitaxial wafer 410a with a spot expansion layer 412. As shown in FIG. 12b, the main peak of the light field of laser epitaxial wafer 410a is concentrated in quantum well layer 414, and the light field of laser epitaxial wafer 410a mainly expands to N-doped region, so that the light field of laser epitaxial wafer 410a is mainly distributed in quantum well layer 414 and N-doped region. The light absorption rate of N-doped region is smaller than that of P-doped region, which reduces the loss of light field in P-doped region.

[0135] FIG. 13 is a partial view of another laser epitaxial wafer according to some embodiments. As shown in FIG. 13, the spot expansion layer 412 includes a first InP layer 4121a, a first InGaAsP layer 4122a, a second InP layer 4121b, and a second InGaAsP layer 4122b. The first InP layer 4121a is located above the N-type InP layer 411, the first InGaAsP layer 4122a is located above the first InP layer 4121a, the second InP layer 4121b is located above the first InGaAsP layer 4122a, and the second InGaAsP layer 4122b is located above the second InP layer 4121b. The refractive index of the first InGaAsP layer 4122a is greater than the refractive index of the first InP layer 4121a, the refractive index of the second InGaAsP layer 4122b is greater than the refractive index of the second InP layer 4121b, the refractive index of the second InGaAsP layer 4122b is greater than the refractive index of the N-type confinement layer 413, and the refractive index of the first InGaAsP layer 4122a is greater than the refractive index of the second InP layer 4121b. The second InGaAsP layer 4122b and the first InGaAsP layer 4122a can expand the optical field of the laser epitaxial wafer 410a towards the N-doped region, and the second InP layer 4121b and the first InP layer 4121a can reduce the over-expansion of the optical field of the laser epitaxial wafer 410a towards the N-doped region. Thus, the second InGaAsP layer 4122b and the first InGaAsP layer 4122a in combination with the second InP layer 4121b and the first InP layer 4121a can expand the optical field of the laser epitaxial wafer 410a towards the N-doped region while ensuring that the main peak of the optical field of the laser epitaxial wafer 410a is located in the region of the quantum well layer 414.

[0136] In some embodiments, the first InP layer 4121a, the first InGaAsP layer 4122a, the second InP layer 4121b, and the second InGaAsP layer 4122b are sequentially grown above the N-type InP layer 411. The first InP layer 4121a and the second InP layer 4121b can be formed by growing N-type InP material, and the refractive index of the first InP layer 4121a and the second InP layer 4121b can be equal. The first InGaAsP layer 4122a and the second InGaAsP layer 4122b can be formed by growing N-type InGaAsP material, and the refractive index of the first InGaAsP layer 4122a and the second InGaAsP layer 4122b can be equal.

[0137] In some embodiments, the thickness of the first InGaAsP layer 4122a is greater than the thickness of the first InP layer 4121a, and the thickness of the second InGaAsP layer 4122b is greater than the thickness of the second InP layer 4121b. For example, the thickness of the first InGaAsP layer 4122a is twice the thickness of the first InP layer 4121a, and the thickness of the second InGaAsP layer 4122b is twice the thickness of the second InP layer 4121b, although the embodiments are not limited thereto in some embodiments.

[0138] In some embodiments, the thickness of the first InGaAsP layer 4122a can be equal to the thickness of the second InGaAsP layer 4122b, and the thickness of the first InP layer 4121a can be equal to the thickness of the second InP layer 4121b, although the embodiments are not limited thereto in some embodiments.

[0139] Based on the laser epitaxial wafer 410a provided in the above embodiments, a laser epitaxial wafer preparation method is also provided in some embodiments. FIG. 14 is a flowchart of a laser epitaxial wafer preparation method according to some embodiments. In some embodiments, as shown in FIG. 14, the laser epitaxial wafer preparation method includes:

[0140] S100: forming an N-type InP layer on a substrate.

[0141] The N-type InP layer 411 is grown on a substrate. The substrate can be an InP substrate. In some embodiments, the N-type InP semiconductor material is grown on the InP substrate to form the N-type InP layer 411.

[0142] S200: forming a spot expansion layer on the N-type InP layer.

[0143] The spot expansion layer 411 can be grown using an N-type InP semiconductor material with relatively large refractive index, such as N-type InGaAsP.

[0144] In some embodiments, S200: forming a spot expansion layer on the N-type InP layer includes:

[0145] S210: sequentially forming an InP layer and an InGaAsP layer on the N-type InP, the refractive index of the InGaAsP being greater than the refractive index of the InP layer.

[0146] In some embodiments, the InP layer 4121 is grown on the N-type InP 411, and the InGaAsP layer 4122 is formed on the InP layer 4121. The InP layer 4121 can be grown using N-type InP material, and the InGaAsP layer 4122 can be grown using N-type InGaAsP material.

[0147] In some embodiments, S200: forming a spot expansion layer on the N-type InP layer, comprises:

[0148] S220: sequentially forming a first InP layer, a first InGaAsP layer, a second InP layer and a second InGaAsP layer on the N-type InP layer; the refractive index of the first InGaAsP layer is greater than the refractive index of the first InP layer, the refractive index of the second InGaAsP layer is greater than the refractive index of the second InP layer, and the refractive index of the first InGaAsP layer is greater than the refractive index of the second InP layer.

[0149] In some embodiments, the first InP layer 4121a is formed by growing on the N-type InP 411, the first InGaAsP layer 4122a is formed by growing on the first InP layer 4121a, the second InP layer 4121b is formed by growing on the first InGaAsP layer 4122a, and the second InGaAsP layer 4122b is formed by growing on the second InP layer 4121b. The refractive index of the first InGaAsP layer 4122a is greater than the refractive index of the first InP layer 4121a, the refractive index of the second InGaAsP layer 4122b is greater than the refractive index of the second InP layer 4121b, and the refractive index of the first InGaAsP layer 4122a is greater than the refractive index of the second InP layer 4121b. The first InP layer 4121a and the second InP layer 4121b can be formed by growing N-type InP material, and the first InGaAsP layer 4122a and the second InGaAsP layer 4122b can be formed by growing N-type InGaAsP material.

[0150] S300: forming an N-type confinement layer on the spot expansion layer, the refractive index of the N-type confinement layer being less than the refractive index of the second InGaAsP layer.

[0151] In some embodiments, the N-type confinement layer 413 is formed by growing on the spot expansion layer 412, and the refractive index of the N-type confinement layer 413 is less than the refractive index of the spot expansion layer 412. The N-type confinement layer 413 can be formed by growing N-type InP semiconductor material. For example, the N-type InP semiconductor material is grown on the spot expansion layer 412 to form the N-type confinement layer 413.

[0152] In some embodiments, the N-type confinement layer 413 is formed by growing on the InGaAsP layer 4122.

[0153] In some embodiments, the N-type confinement layer 413 is formed by growing on the second InGaAsP layer 4122b.

[0154] S400: forming a quantum well layer on the N-type confinement layer.

[0155] In some embodiments, the quantum well layer 414 includes multiple pairs of quantum wells. The quantum well layer 414 can be a multi-layer structure grown by alternating thin layers of different semiconductor materials.

[0156] In some embodiments, S400: forming a quantum well layer on the N-type confinement layer, includes:

[0157] S410: sequentially forming multiple pairs of quantum wells on the N-type confinement layer, the multiple pairs of quantum wells including wells with different band gap widths.

[0158] In some embodiments, each pair of quantum wells is grown sequentially on the N-type confinement layer 413, and the multiple pairs of quantum wells include wells with different band gap widths. Each pair of quantum wells is formed by alternating thin layers of different semiconductor materials, and the band gap width of the wells in the quantum well is related to the composition of the semiconductor material. The material used to form the quantum well can be InGaAsP, and the band gap width of the wells in the quantum well can be adjusted by adjusting the proportion of each element in the InGaAsP.

[0159] In some embodiments, the laser epitaxial wafer preparation method further includes: forming a P-type confinement layer on the quantum well layer.

[0160] In some embodiments, the P-type confinement layer 415 can be grown from P-type InP semiconductor material. The P-type confinement layer 415 is grown on the quantum well layer 414 using P-type InP semiconductor material.

[0161] In some embodiments, the laser epitaxial wafer preparation method further includes: forming a P-type InP layer on the P-type confinement layer.

[0162] In some embodiments, the P-type confinement layer 416 can be grown from P-type InP semiconductor material. The P-type InP layer 416 is grown above the P-type confinement layer 415 using P-type InP semiconductor material.

[0163] Based on the laser epitaxial wafer 410a or the laser epitaxial wafer preparation method provided in the above embodiments, in some embodiments, a laser chip preparation method is also provided. In some embodiments, the laser chip preparation method includes: growing a laser epitaxial wafer; etching the laser epitaxial wafer to form a ridge waveguide, the etching depth being to the N-type confinement layer of the laser epitaxial wafer; and forming an electrode on the ridge waveguide.

[0164] The above description is merely a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who thinks of changes or replacements within the technical scope disclosed by the present disclosure should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. An optical module comprising: a circuit board; an optical transmitting component electrically connected to the circuit board; the optical transmitting component comprising: a laser chip for generating an optical signal; the laser chip being formed from an etched laser epitaxial wafer; wherein the laser epitaxial wafer comprises: an N-type InP layer; an N-type confinement layer located above the N-type InP layer; a quantum well layer located above the N-type confinement layer; wherein a spot expansion layer is formed between the N-type InP layer and the N-type confinement layer, the spot expansion layer comprising: a first InP layer located above the N-type InP layer; a first InGaAsP layer located above the first InP layer, the first InGaAsP layer having a refractive index greater than the refractive index of the first InP layer; a second InP layer located above the first InGaAsP layer, the second InP layer having a refractive index less than the refractive index of the first InGaAsP layer; a second InGaAsP layer located above the second InP layer, the top of the second InGaAsP layer being connected to the N-type confinement layer; the second InGaAsP layer having a refractive index greater than the refractive index of the N-type confinement layer and the second InGaAsP layer having a refractive index greater than the refractive index of the second InP layer.

2. The optical module according to claim 1, wherein the quantum well layer comprising a plurality of pairs of quantum wells, the plurality of pairs of quantum wells comprising wells having different bandgaps.

3. An optical module comprising: a circuit board; an optical transmitting component electrically connected to the circuit board; the optical transmitting component comprising: a laser chip for generating an optical signal; the laser chip being formed from an etched laser epitaxial wafer; wherein the laser epitaxial wafer comprises: an N-type InP layer; an N-type confinement layer located above the N-type InP layer; a quantum well layer located above the N-type confinement layer; wherein a spot expansion layer is formed between the N-type InP layer and the N-type confinement layer, the spot expansion layer comprising: an InP layer located above the N-type InP layer, an InGaAsP layer located above the InP layer, the InGaAsP layer having a refractive index greater than the refractive index of the N-type InP layer and the InGaAsP layer having a refractive index greater than the refractive index of the InP layer.

4. The optical module according to claim 3, wherein the quantum well layer comprising a plurality of pairs of quantum wells, the plurality of pairs of quantum wells comprising wells having different bandgaps.

5. A laser epitaxial wafer comprising: an N-type InP layer; an N-type confinement layer located above the N-type InP layer; a quantum well layer located above the N-type confinement layer; wherein a spot expansion layer is formed between the N-type InP layer and the N-type confinement layer, the spot expansion layer comprising: a first InP layer located above the N-type InP layer; a first InGaAsP layer located above the first InP layer, the first InGaAsP layer having a refractive index greater than the refractive index of the first InP layer; a second InP layer located above the first InGaAsP layer, the second InP layer having a refractive index less than the refractive index of the first InGaAsP layer. A second InGaAsP layer is located above the second InP layer and is connected to the N-type confinement layer at the top; the refractive index of the second InGaAsP layer is greater than the refractive index of the N-type confinement layer and the refractive index of the second InGaAsP layer is greater than the refractive index of the second InP layer.

6. The laser epitaxial wafer of claim 5, wherein, The quantum well layer includes multiple pairs of quantum wells, and the multiple pairs of quantum wells include wells with different band gap widths.

7. A laser epitaxial wafer, comprising: An N-type InP layer; An N-type confinement layer located above the N-type InP layer; A quantum well layer located above the N-type confinement layer; The N-type InP layer and the N-type confinement layer form a spot expansion layer therebetween, and the spot expansion layer includes: An InP layer located above the N-type InP layer, An InGaAsP layer located above the InP layer, the refractive index of the InGaAsP layer is greater than the refractive index of the N-type InP layer, and the refractive index of the InGaAsP layer is greater than the refractive index of the InP layer.

8. The laser epitaxial wafer of claim 7, wherein, The quantum well layer includes multiple pairs of quantum wells, and the multiple pairs of quantum wells include wells with different band gap widths.

9. A laser epitaxial wafer preparation method for preparing a laser epitaxial wafer for etching to form a laser chip; the preparation method comprises: forming an N-type InP layer on a substrate; forming a spot expansion layer on the N-type InP layer, the spot expansion layer includes a first InP layer, a first InGaAsP layer, a second InP layer, and a second InGaAsP layer stacked from bottom to top; wherein the refractive index of the first InGaAsP layer is greater than the refractive index of the first InP layer, the refractive index of the second InGaAsP layer is greater than the refractive index of the second InP layer, and the refractive index of the first InGaAsP layer is greater than the refractive index of the second InP layer; forming an N-type confinement layer on the spot expansion layer, the refractive index of the N-type confinement layer is less than the refractive index of the second InGaAsP layer; forming a quantum well layer on the N-type confinement layer.

10. The production method according to claim 9, wherein forming a quantum well layer on the N-type confinement layer, including: forming multiple pairs of quantum wells on the N-type confinement layer in sequence, and the multiple pairs of quantum wells include wells with different band gap widths.

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