Monolithic integrated light emitting chip and manufacturing method thereof

Abstract

The invention discloses a monolithic integrated light emitting chip and a manufacturing method thereof, and relates to the technical field of semiconductor devices.The chip comprises a substrate, a passive waveguide layer, a first laser layer, a second laser layer, a modulator layer, a wrapping layer and a contact layer, the passive waveguide layer is formed by etching according to a preset pattern, and the first laser layer is formed on the substrate; comprising two input branches and an output branch, a first laser layer is arranged on one of the input branches, a second laser layer and a modulator layer are arranged on the other optical signal input branch, paths of the two input branches are coupled into a path of the output branch, gratings are arranged on the two laser layers, and the modulator layer is arranged on the output branch. A cladding and a contact layer are disposed over the functional layers. The two different laser layers are integrated in the chip, and the optical signals emitted by the different laser layers are combined and output through the passive waveguide layer with the predetermined pattern, so that the cost of the optical emission module is effectively reduced, the power consumption is reduced, and the product reliability is improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and in particular to a monolithic integrated light emitting chip and a method for manufacturing the same. Background Art

[0002] Passive optical network (PON) is the future development direction of access network. On the one hand, it is widely favored in solving broadband access problems because the bandwidth it provides can meet the needs of various broadband services now and in the future; on the other hand, its cost is relatively low in terms of equipment cost and operation and maintenance management expenses. Comprehensive economic and technical analysis shows that PON is the main technology for realizing fiber to the building (FTTB) and fiber to the home (FTTH).

[0003] In order to achieve a smooth evolution of a large number of Gigabit Passive Optical Networks (GPON) in the existing network to 10G Passive Optical Networks (XGPON), the industry has proposed a combined passive optical network solution (Combo PON). This solution integrates two generations of PON into a single board and optical module to achieve compatibility between the two PON technologies, such as compatibility between GPON and XG-PON, and compatibility between GPON and symmetric 10G passive optical network (XGS-PON). Currently in the Combo PON solution, the two light source devices used for GPON and 10G GPON are combined in two channels in one optical module and output from the same optical port. Figure 4 As shown, since the light source devices of the two wavelengths need to be manufactured independently, and the technology and process required to package and integrate the light source devices of the two wavelengths λ1 and λ2 in the same optical module for combined output are relatively complex, the cost of the Combo PON optical transmitter module is relatively high, which is specifically reflected in the difficulty in coupling the independently manufactured light source devices and the high precision required for welding. The coupling structure needs to be accurately designed during the manufacturing process to improve the combining effect, and high-precision welding is required during integration to ensure the product yield; in addition, the use of discrete devices also leads to high power consumption and poor reliability of the module, and large optical fiber loss used to transmit optical signals. These problems have limited the widespread use of Combo PON. Summary of the invention

[0004] The purpose of this application is to provide a monolithic integrated optical transmission chip and a preparation method for Combo PON, integrate two different laser layers in the chip, and combine and output the optical signals emitted by different laser layers through a passive waveguide layer with a predetermined pattern, thereby reducing the production cost, reducing power consumption, and improving product reliability.

[0005] The technical solution of the present application is: to provide a method for manufacturing a monolithic integrated light emitting chip, the method comprising:

[0006] Step 1, preparing a substrate, growing a passive waveguide material on the substrate, and etching the passive waveguide material layer according to a predetermined pattern to form a passive waveguide layer, wherein the passive waveguide layer includes a first input branch, a second input branch, and an output branch, a first laser region and a first amplifier region are divided in the region where the first input branch is located, a second laser region, a modulator region, and a second amplifier region are divided in the region where the second input branch is located, and a third amplifier region is divided in the region where the output branch is located;

[0007] Step 2, growing a short-wavelength quantum well material layer at least in the region where the first input branch is located, and selectively removing the short-wavelength quantum well material in other regions except the first laser region and the first amplifier region to form a first laser layer and a first amplifier layer;

[0008] Step 3, respectively making a pair of selective area epitaxial masks with a specific spacing on both sides of the second laser region and the second amplifier region, then growing a long wavelength quantum well material layer at least in the region where the second input branch and the output branch are located, and selectively removing the long wavelength quantum well material in other regions except the second laser region, the modulator region, the second amplifier region and the third amplifier region, to form a second laser layer, a modulator layer, a second amplifier layer and a third amplifier layer;

[0009] Step 4, forming a first grating layer and a second grating layer on the first laser layer and the second laser layer respectively;

[0010] Step 5, growing cladding layers and contact layers on each functional layer from bottom to top, using a mask to cover the contact layers in areas other than the laser area, amplifier area and modulator area, and performing p-type doping on the cladding layers and contact layers in uncovered areas.

[0011] Furthermore, step 1 also includes:

[0012] A buffer layer is grown on the substrate, wherein the buffer layer is located between the passive waveguide layer and the substrate.

[0013] Furthermore, the length of the selective area epitaxial mask pairs on both sides of the second laser region is the same as the length of the second laser region, the length of the selective area epitaxial mask pairs on both sides of the second amplifier region is the same as the length of the second amplifier region, and the specific spacings of the two pairs of selective area epitaxial mask pairs both meet the condition that the light emission wavelength of the modulator layer and the third amplifier layer is 30 to 100 nm shorter than the light emission wavelength of the second laser layer and the second amplifier layer.

[0014] Furthermore, the preparation method also includes: selectively removing the contact layer in areas other than the areas where the laser layer, the amplifier layer and the modulator layer are located.

[0015] Further, the first laser layer uses a short-wavelength quantum well material InGaAsP or InGaAlAs, and the band gap wavelength is 1450 to 1510 nm;

[0016] The second laser layer uses a long wavelength quantum well material InGaAsP or InGaAlAs, and the band gap wavelength is 1450 to 1510nm;

[0017] The bandgap wavelength of the passive waveguide layer is 1100nm to 1400nm;

[0018] The Bragg wavelength of the first grating layer is 1450 to 1510 nm, and the Bragg wavelength of the second grating layer is 1530 to 1580 nm.

[0019] The present application also provides a monolithic integrated light emitting chip prepared by the method for preparing a monolithic integrated light emitting chip, the monolithic integrated light emitting chip comprising:

[0020] The monolithic integrated light emitting chip comprises: a substrate, a passive waveguide layer, a first laser layer, a first grating layer, a second laser layer, a second grating layer, a modulator layer, a cladding layer and a contact layer;

[0021] The passive waveguide layer is formed by etching the passive waveguide layer material grown on the entire surface of the substrate according to a predetermined pattern, and the passive waveguide layer includes a first input branch, a second input branch and an output branch, wherein the first input branch and the second input branch are commonly coupled to the output branch;

[0022] The first laser layer is arranged on the first input branch and is located at an end far away from the coupling position, and the first grating layer is arranged on the first laser layer;

[0023] A second laser layer is arranged in a selective growth region defined by the first mask pair on the second input branch, the second laser layer is located at an end away from the coupling position, and a second grating layer is arranged on the second laser layer;

[0024] The modulator layer is arranged on the second input branch and is located between the position where the second laser layer is located and the coupling position;

[0025] The cladding layer and the contact layer are sequentially arranged on each functional layer from bottom to top.

[0026] Further, the monolithic integrated light emitting chip further comprises a first amplifier layer, a second amplifier layer and a third amplifier layer;

[0027] The first amplifier layer is arranged on the first input branch and is located between the position where the first laser layer is located and the coupling position, and is used for amplifying the optical signal generated by the first laser layer;

[0028] The second amplifier layer is arranged in a selective growth region defined by a second mask pair on the second input branch and is located between a position where the modulator layer is located and a coupling position, and is used to amplify the modulated optical signal of the second laser layer. The width of the region where the second amplifier layer is located is limited by a second mask pair with a specific spacing.

[0029] The third amplifier layer is arranged on the output branch, and is used for amplifying the optical signal coupled to the output branch from the two input branches.

[0030] Further, the length of the first mask pair is the same as the length of the second laser layer, and the length of the second mask pair is the same as the length of the second amplifier layer;

[0031] The modulator layer is located between the area where the second laser layer is located and the area where the second amplifier layer is located;

[0032] The light emission wavelengths of the modulator layer and the third amplifier layer are shorter than the light emission wavelengths of the second laser layer and the second amplifier layer.

[0033] Further, the cladding includes a doped portion and an undoped portion;

[0034] The doped part is located above the first grating layer, the second grating layer, the modulator layer, the first amplifier layer, the second amplifier layer and the third amplifier layer. The doped part is formed by p-type doping. The undoped part is located above the passive waveguide layer. The contact layer is arranged above the doped part.

[0035] Furthermore, the monolithic integrated light emitting chip further includes a buffer layer, and the buffer layer is arranged between the substrate and the passive waveguide layer.

[0036] The beneficial effects of this application are:

[0037] The technical solution in the present application utilizes monolithic integration technology to manufacture lasers with different emission wavelengths for GPON and XGPON on the same substrate, and combines the optical signals emitted by different lasers through a passive waveguide layer with a specific pattern for output. Compared with the method in the prior art of packaging and integrating independently manufactured light source devices of different wavelengths in the same optical module for combined output, the technical solution in the present application directly uses a passive waveguide layer with a specific pattern for combining, thereby eliminating the steps of accurately designing a coupling structure for discrete devices in the optical module and performing high-precision welding during subsequent packaging and integration, and can effectively reduce the production cost of the Combo PON optical transmission module. Moreover, the technical solution in the present application is an integrated design with rigorous process, and has higher reliability and yield rate than the design that requires assembly in the prior art, thereby avoiding connection problems, material mismatch and other problems that occur during the assembly and integration process.

[0038] The technical solution in this application uses a passive waveguide layer to complete the combined wave output, which has lower power consumption than the combined wave output method using optical fiber and combiner in the prior art. The technical solution in this application also performs p-type doping on the cladding and contact layer, and removes the contact layer above the passive waveguide layer, further reducing the waveguide transmission loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The advantages of the above and / or additional aspects of the present application will become apparent and easily understood in the description of the embodiments in conjunction with the following drawings, in which:

[0040] Figure 1 is a schematic structural diagram of a passive waveguide layer of a monolithically integrated light emitting chip according to the present application;

[0041] Figure 2 is a schematic diagram of the cross-sectional structure of the first laser layer of the monolithic integrated light emitting chip according to the present application;

[0042] Figure 3 is a schematic diagram of the cross-sectional structure of the second laser layer of the monolithically integrated light emitting chip according to the present application;

[0043] Figure 4 It is a partial structural diagram of an optical module compatible with two generations of PON in the prior art;

[0044] Among them, 10-substrate, 20-buffer layer, 30-passive waveguide layer, 40-first laser layer, 41-first grating layer, 50-second laser layer, 51-second grating layer, 60-modulator layer, 71-first amplifier layer, 72-second amplifier layer, 73-third amplifier layer, 80-cladding, 81-doped part, 82-undoped part, 90-contact layer, 100-first mask pair, 200-second mask pair. DETAILED DESCRIPTION

[0045] In order to more clearly understand the above-mentioned purposes, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0046] In the following description, many specific details are elaborated to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present application is not limited to the specific embodiments disclosed below.

[0047] Taking the InP-based material system as an example, a monolithic integrated light emitting chip and a manufacturing method thereof in an embodiment of the present invention are generally introduced below.

[0048] like Figures 1 to 3As shown, this embodiment provides a monolithic integrated light emitting chip, which includes a substrate 10, a passive waveguide layer 30, a first laser layer 40, a first grating layer 41, a second laser layer 50, a second grating layer 51, a modulator layer 60, a cladding layer 80 and a contact layer 90.

[0049] The passive waveguide layer 30 is formed by etching the passive waveguide layer material grown on the entire surface of the substrate 10 according to a predetermined pattern. The area where the passive waveguide layer 30 is located is a passive waveguide region (WG). The passive waveguide layer 30 includes a first input branch, a second input branch and an output branch. The first input branch and the second input branch are optical signal input branches, and the output branch is an optical signal output branch. The first input branch and the second input branch are coupled to the output branch together, wherein the position where the first input branch, the second input branch and the output branch are connected is a coupling position.

[0050] The first laser layer 40 is arranged on the first input branch of the passive waveguide layer 30 and is located at an end of the input branch away from the coupling position. The area where the first laser layer 40 is located is the first laser region (DFB1). The first grating layer 41 is arranged on the first laser layer 40. The first input branch is used to receive the optical signal emitted by the first laser layer 40. The second input branch is used to receive the optical signal emitted by the second laser layer 50.

[0051] The second laser layer 50 is arranged in a selective growth area of ​​a specific pitch on the second input branch limited by the first mask pair 100 (SAG mask) (that is, it is arranged on the second input branch by using the mask pair to adjust the width of the intermediate selective growth area), and the second laser layer 50 is located at an end of the second input branch away from the coupling position. The area where the second laser layer 50 is located is the second laser block (DFB2), and the second grating layer 51 is arranged on the second laser layer 50; wherein the length of the first mask pair 100 is the same as the length of the second laser layer 50.

[0052] The modulator layer 60 is arranged on the second input branch of the second laser layer 50 and is adjacent to the second laser layer 50. The modulator layer 60 is located between the position of the second laser layer 50 and the coupling position. The area where the modulator layer 60 is located is the modulator area (EAM). The light emission wavelength of the modulator layer 60 is 30nm to 100nm shorter than the light emission wavelength of the second laser layer 50.

[0053] The first grating layer 41 and the second grating layer 51 can be uniform periodic gratings, and a phase shift structure can also be introduced therein. The Bragg wavelength of the first grating layer 41 is 1450 to 1510 nm, and the Bragg wavelength of the second grating layer 51 is 1530 to 1580 nm. In this embodiment, the first grating layer 41 can be manufactured on the first laser layer 40, and the second grating layer 51 can be manufactured on the second laser layer 50 by etching.

[0054] The passive waveguide layer 30 can be made of InGaAsP material with a thickness of 200 to 800 nm and a band gap wavelength of 1100 to 1400 nm. The first laser layer 40 can be made of short-wavelength quantum well material InGaAsP (indium gallium arsenic phosphide) or InGaAlAs (indium gallium aluminum arsenic) with a band gap wavelength of 1450 to 1510 nm. The second laser layer 50 can be made of long-wavelength quantum well material InGaAsP or InGaAlAs with a band gap wavelength of 1530 to 1580 nm. The substrate 10 can be made of InP substrate.

[0055] The first mask pair 100 is a selective area epitaxial mask pair, and silicon oxide material or silicon nitride material can be selected. After the first mask pair 100 is set in the second laser region, the long wavelength quantum well material of the second laser layer 50 can only grow in an area of ​​a specific width in the middle position of the first mask pair 100, and the area covered by the mask will not grow. By adjusting the spacing of the first mask pair 100, the width of the second laser layer 50 can be controlled, thereby achieving the adjustment of the emission wavelength of the second laser layer 50.

[0056] The monolithically integrated light emitting chip further includes a first amplifier layer 71 , a second amplifier layer 72 and a third amplifier layer 73 .

[0057] The first amplifier layer 71 is arranged on the first input branch and is located above the passive waveguide layer 30 between the position where the first laser layer 40 is located and the coupling position. The first amplifier layer 71 is close to the first laser layer 40 and is used to amplify the optical signal generated by the first laser layer 40. The area where the first amplifier layer 71 is located is the first amplifier area (SOA1).

[0058] The second amplifier layer 72 is arranged in a selective growth region of a specific width limited by the second mask pair 200 on the second input branch. The second amplifier layer 72 is located above the passive waveguide layer 30 between the position of the modulator layer 60 and the coupling position, that is, located on the side of the modulator layer 60 away from the second laser layer 50. The second amplifier layer 72 is close to the modulator layer 60 and is used to amplify the optical signal modulated by the modulator layer 60. The region where the second amplifier layer 72 is located is the second amplifier area (SOA2); wherein the length of the second mask pair 200 is the same as the length of the second amplifier layer 72.

[0059] The third amplifier layer 73 is disposed on the output branch of the passive waveguide layer 30, and is used to amplify the optical signal coupled from the two optical signal input branches to the optical signal output branch. The area where the third amplifier layer 73 is located is the third amplifier area (SOA3). The emission wavelength of the third amplifier layer 73 and the modulator layer 60 is 30nm to 100nm shorter than the emission wavelength of the second laser layer 50 and the second amplifier layer 72.

[0060] The first amplifier layer 71 can be made of short-wavelength quantum well material InGaAsP or InGaAlAs, with a band gap wavelength of 1450 to 1510 nm. The second amplifier layer 72 and the third amplifier layer 73 can be made of long-wavelength quantum well material InGaAsP or InGaAlAs, with a band gap wavelength of 1530 to 1580 nm. The second mask pair 200 is also a selective area epitaxy mask pair, and can be made of silicon oxide material or silicon nitride material.

[0061] The cladding 80 is arranged above each functional layer, and these functional layers include the first grating layer 41, the second grating layer 51, the modulator layer 60, the first amplifier layer 71, the second amplifier layer 72, the third amplifier layer 73 and part of the passive waveguide layer 30. The cladding 80 can be formed by etching the cladding material grown on the entire surface of the substrate 10 according to a predetermined pattern, that is, after etching, the cladding material above each functional layer forms the cladding 80, and the cladding 80 includes a doped part 81 and an undoped part 82.

[0062] The doped portion 81 is located above the first grating layer 41, the second grating layer 51, the modulator layer 60, the first amplifier layer 71, the second amplifier layer 72 and the third amplifier layer 73. The doped portion 81 is formed by performing p-type doping on the cladding 80 in the area where these functional layers are located. The undoped portion 82 is arranged above the passive waveguide layer 30 outside the area where the first grating layer 41, the second grating layer 51, the modulator layer 60, the first amplifier layer 71, the second amplifier layer 72 and the third amplifier layer 73 are located. The undoped portion 82 is the undoped portion of the cladding 80.

[0063] The contact layer 90 is disposed on the doped portion 81 and is a p-type doped contact layer 90. The contact layer 90 can be formed by etching the contact layer material grown on the entire surface of the substrate 10 according to a predetermined pattern, that is, the contact material in the area where the doped portion 81 is located is etched to form the contact layer 90.

[0064] The cladding 80 can be made of undoped InP material, and the contact layer 90 can be made of undoped InGaAs material. In this embodiment, the cladding 70 and the contact layer 80 can be set in the corresponding area by etching, and the Zn extended doping technology can be used to dope part of the cladding 80 and the contact layer 90, wherein the material of the mask can be SiO2. Specifically, the SiO2 mask can be used to cover the cladding 80 and the contact layer 90 outside the area where the first grating layer 41, the second grating layer 51, the first amplifier layer 71, the second amplifier layer 72 and the third amplifier layer 73 are located, and the Zn extended doping technology is used to perform p-type doping. After the p-type doping is completed, the mask is removed, and the area covered by the mask is the undoped part, and the undoped part can reduce the waveguide transmission loss. The contact layer 90 is not set above the cladding 80 outside the area where the first grating layer 41, the second grating layer 51, the modulator layer 60, the first amplifier layer 71, the second amplifier layer 72 and the third amplifier layer 73 are located, and the purpose is to reduce the waveguide transmission loss.

[0065] The monolithic integrated light emitting chip further includes a buffer layer 20. The buffer layer 20 is disposed between the substrate 10 and the passive waveguide layer 30 to alleviate the lattice mismatch problem between the substrate 10 and the functional layer, and reduce stress and manufacturing defects. The buffer layer 20 can be made of InP material.

[0066] This embodiment also provides a method for manufacturing a monolithic integrated light emitting chip, the manufacturing method comprising:

[0067] Step 1, preparing a substrate 10, sequentially growing a buffer layer 20 and a passive waveguide material on the substrate 10, and etching the passive waveguide material layer according to a predetermined pattern to form a passive waveguide layer 30, wherein the passive waveguide layer 30 includes a first input branch, a second input branch, and an output branch, wherein a first laser region and a first amplifier region are divided in an area where the first input branch is located, a second laser region, a modulator region, and a second amplifier region are divided in an area where the second input branch is located, and a third amplifier region is divided in an area where the output branch is located;

[0068] Step 2, growing a short-wavelength quantum well material layer at least in the region where the first input branch is located, selectively removing the short-wavelength quantum well material in other regions except the first laser region and the first amplifier region, the short-wavelength quantum well material in the first laser region forming the first laser layer 40, and the short-wavelength quantum well material in the first amplifier region forming the first amplifier layer 71;

[0069] Step 3, making a pair of selective epitaxial mask with a specific spacing on both sides of the second input branch of the second laser region and the second amplifier region respectively, then growing a long wavelength quantum well material layer at least in the region where the second input branch and the output branch are located, selectively removing the long wavelength quantum well material in other regions except the second laser region, the modulator region, the second amplifier region and the third amplifier region, to form a second laser layer 50, a modulator layer 60, a second amplifier layer 72 and a third amplifier layer 73; wherein the length of the selective epitaxial mask pair of the second laser region is the same as the length of the second laser region, the length of the selective epitaxial mask pair of the second amplifier region is the same as the length of the second amplifier region, and the specific spacing of the selective epitaxial mask pairs of the two regions both meet the condition that the emission wavelengths of the modulator layer 60 and the third amplifier layer 73 are 30 to 100 nm shorter than the emission wavelength of the second laser layer 50.

[0070] Step 4, forming a first grating layer 41 and a second grating layer 51 on the first laser layer 40 and the second laser layer 50 respectively;

[0071] Step 5, grow undoped cladding 80 and contact layer 90 on each functional layer from bottom to top, use a mask to cover other areas outside the laser area, amplifier area and modulator area, and perform p-type doping on the cladding 80 and contact layer 90 in the uncovered area, and selectively remove the contact layer 90 in other areas outside the laser area, amplifier area and modulator area.

[0072] In this embodiment, in order not to affect the function of the passive waveguide layer 30, it is necessary to etch the passive waveguide material layer according to a predetermined pattern after growing the passive waveguide material layer to form a passive waveguide layer 30 including two input branches and one output branch, so that the passive waveguide layer 30 can couple the optical signal to the output branch through the two input branches to achieve the function of combining waves. Taking the Y-type pattern as an example, during operation, a gap of 3-6 um can be set around the Y-type passive waveguide area by etching, and the passive waveguide material layer in the Y-type passive waveguide area is used as the passive waveguide layer 30.

[0073] Taking the InP-based material system as an example, the substrate 10 is an InP substrate, the buffer layer 20 is an InP buffer layer material, the passive waveguide layer 30 is an InGaAsP material, the first laser layer 40 and the first amplifier layer 71 are short-wavelength quantum well materials InGaAsP or InGaAlAs, and the band gap wavelength is controlled between 1450 and 1510 nm by adjusting the ratio of the elements, and the second laser layer 50, the modulator layer 60, the second amplifier layer 72 and the third amplifier layer 73 are long-wavelength quantum well materials InGaAsP or InGaAlAs The band gap wavelength is controlled between 1530 and 1580 nm by adjusting the ratio of elements. The first grating layer 41 and the second grating layer 51 use uniform periodic gratings or gratings with phase shift structures. The Bragg wavelength of the first grating layer 41 is adjusted to between 1450 and 1510 nm, and the Bragg wavelength of the second grating layer 51 is adjusted to between 1530 and 1580 nm. The cladding layer 80 uses InP cladding material, the contact layer 90 uses InGaAs contact layer material, and the selective area epitaxial mask and other masks use silicon oxide material or silicon nitride material, such as SiO2 film.

[0074] The specific production method is:

[0075] First, InP buffer layer material and passive waveguide layer material are sequentially grown on the entire surface of a cleaned InP substrate, wherein the thickness of the passive waveguide layer material is between 200 and 800 nm, and the passive waveguide layer material is etched according to a predetermined pattern of the WG region to form a passive waveguide layer 30 including a first input branch, a second input branch and an output branch, and the WG region is divided into a DFB1 region, a DFB2 region, an EAM region, a SOA1 region, a SOA2 region and a SOA3 region; a short-wavelength quantum well material is grown on the first input branch, and the short-wavelength quantum well materials of the DFB1 region and the SOA1 region are retained, and the short-wavelength quantum well materials of other regions are removed, and the material of the DFB1 region is used as the first laser layer 40, and the material of the SOA1 region is used as the first amplifier layer 71.

[0076] In this embodiment, each functional layer can be grown on the InP substrate by using molecular beam epitaxy (MBE) or chemical vapor deposition (MOCVD) technology, and the whole surface growth or partial growth can be selected. After the growth is completed, the material affecting the functional layer in other areas can be removed by etching. In order not to affect the function of the passive waveguide material layer in the passive waveguide area, the passive waveguide material layer is etched according to a predetermined pattern by etching, and a gap of 3-6 um is set around the passive waveguide area.

[0077] Then, a first mask pair 100 with a specific spacing is made on both sides of the passive waveguide layer 30 in the DFB2 region, and a second mask pair 200 with a specific spacing is made on both sides of the passive waveguide layer 30 in the SOA2 region. After the mask pair is made, a long wavelength quantum well material is grown on the second input branch and the output branch, and the long wavelength quantum well materials in the DFB2 region, the EAM region, the SOA2 region and the SOA3 region are retained, and the long wavelength quantum well materials in other regions are removed. The long wavelength quantum well materials in the DFB2 region, the EAM region, the SOA2 region and the SOA3 region are used as the second laser layer 50, the modulator layer 60, the second amplifier layer 72 and the third amplifier layer 73 in sequence, wherein, under the effect of the specific spacing between the first mask pair 100 and the second mask pair 200, the light emission wavelengths of the modulator layer 60 and the third amplifier layer 73 are 30nm to 100nm shorter than the light emission wavelengths of the second laser layer 50 and the second amplifier layer 72.

[0078] In this embodiment, when a selective area epitaxial mask pair with a specific pitch is manufactured in the DFB2 region and the SOA2 region, in order to better control the emission wavelength of the functional layer, the specific range of the specific pitch can be determined by simulation or experiment before manufacturing.

[0079] A first grating layer 41 is made on the first laser layer 40, and a second grating layer 51 is made on the second laser layer 50, wherein the laser layer and the grating layer form a resonant cavity structure, and the grating layer can provide Bragg reflection at a wavelength corresponding to the grating period, thereby forming a feedback mechanism. This mechanism allows photons (the photons are spontaneously radiated by the material itself, and after an external driving current enters the quantum well material, the quantum well material produces a recombination of electrons and holes, and then spontaneously radiates photons) to reflect back and forth in the resonant cavity, and form laser oscillation at a specific wavelength to generate an optical signal output.

[0080] Finally, undoped InP cladding material and InGaAs contact layer material are grown in sequence on top of each functional layer to form a cladding 80 and a contact layer 90. The contact layer 90 in other areas except the DFB1 area, the DFB2 area, the EAM area, the SOA1 area, the SOA2 area and the SOA3 area is covered with a SiO2 film. The cladding 80 and the contact layer 90 in the uncovered area are p-doped using a Zn extended joining technique. After the doping is completed, the SiO2 film is removed. Due to the covering effect of the SiO2 film, the cladding 80 above the passive waveguide layer 30 is an undoped part 82, which can reduce the waveguide transmission loss. The contact layer 90 above the passive waveguide layer 30 is selectively removed to reduce the waveguide transmission loss.

[0081] In this embodiment, the first laser layer 40 and the first grating layer 41 form a first laser, and the modulator layer is not provided on the first input branch. The first laser can be a directly modulated laser. During operation, an external modulation signal can be loaded into the driving current to modulate the light intensity of the first laser. The second laser layer 50 and the second grating layer 51 form a second laser. When the second laser is operating, the driving current remains unchanged, and the optical signal generated by the second laser is externally modulated by the modulator layer 60. The modulator layer 60 is an electro-absorption modulator (EAM). When a voltage is applied by an external power supply, an electric field is generated inside the modulator layer 60 to change the absorption characteristics of the material itself, and the optical signal is modulated by the electro-absorption effect of the material. Specifically, the electric field can increase the absorption coefficient of the modulator layer material. When the optical signal passes through the modulator layer, part of the light is absorbed, resulting in a weakening of the intensity of the optical signal passing through. The absorption coefficient of the modulator layer is controlled by adjusting the magnitude of the applied voltage, thereby dynamically modulating the intensity of the optical signal.

[0082] The first input branch and the second input branch of the passive waveguide layer 30 form a combiner at the coupling position, and the light emitted by the first laser layer 40 and the second laser layer 50 enters the output branch after being combined by the combiner. In this embodiment, the combiner formed by the passive waveguide layer 30 can be a Y-waveguide, an MMI coupler or a directional coupler.

[0083] The first amplifier layer 71 and the second amplifier layer 72 are used to amplify the light emitted by the first laser layer 40 and the second laser layer 50 before combining, respectively, and the third amplifier layer 73 is used to amplify the combined optical signal. After the external current is injected, the amplifier layer forms high-density electrons and holes. When the optical signal passes through the amplifier layer, it induces the electrons and holes to recombine and generate more photons. These new photons increase the intensity of the optical signal, thereby achieving amplification. The amplified optical signal continues to be transmitted through the passive waveguide layer and is finally output.

[0084] Example: InGaAsP is selected as the short-wavelength quantum well material with an element ratio of 0.55:0.45:0.3:0.7, and InGaAsP is selected as the long-wavelength quantum well material with an element ratio of 0.75:0.25:0.93:0.07. After the chip is manufactured, the emission wavelength of the first laser is detected to be approximately 1480nm, and the emission wavelength of the second laser is approximately 1550nm. When a driving current of 100mA is applied, the power of the first input branch optical signal is 30mW, the power of the second input branch optical signal is 28mW, and the power after combined wave is 55mW, which meets the design requirements of this example.

[0085] The steps in this application can be adjusted in order, combined, and deleted according to actual needs.

[0086] The units in the device of the present application can be combined, divided and deleted according to actual needs.

[0087] Although the present application is disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and are not intended to limit the application of the present application. The scope of protection of the present application is defined by the appended claims and may include various modifications, alterations and equivalents made to the invention without departing from the scope and spirit of the present application.

Claims

1. A method for preparing a monolithic integrated light emitting chip, characterized in that: The preparation method comprises: Step 1, preparing a substrate (10), growing a passive waveguide material on the substrate (10), and etching the passive waveguide material layer according to a predetermined pattern to form a passive waveguide layer (30), wherein the passive waveguide layer (30) comprises a first input branch, a second input branch, and an output branch, a first laser region and a first amplifier region are divided in the region where the first input branch is located, a second laser region, a modulator region, and a second amplifier region are divided in the region where the second input branch is located, and a third amplifier region is divided in the region where the output branch is located; Step 2, growing a short-wavelength quantum well material layer at least in the region where the first input branch is located, and selectively removing the short-wavelength quantum well material in other regions except the first laser region and the first amplifier region to form a first laser layer (40) and a first amplifier layer (71); Step 3, respectively making a pair of selective area epitaxial mask with a specific spacing on both sides of the second laser region and the second amplifier region, then growing a long wavelength quantum well material layer at least in the region where the second input branch and the output branch are located, and selectively removing the long wavelength quantum well material in other regions except the second laser region, the modulator region, the second amplifier region and the third amplifier region, to form a second laser layer (50), a modulator layer (60), a second amplifier layer (72) and a third amplifier layer (73); Step 4, forming a first grating layer (41) and a second grating layer (51) on the first laser layer (40) and the second laser layer (50), respectively; Step 5, growing a cladding layer (80) and a contact layer (90) on each functional layer from bottom to top, using a mask to cover the contact layer (90) in other areas except the laser area, the amplifier area and the modulator area, and performing p-type doping on the cladding layer (80) and the contact layer (90) in the uncovered area.

2. The method for preparing a monolithic integrated light emitting chip according to claim 1, characterized in that: The step 1 also includes: A buffer layer (20) is grown on a substrate (10), wherein the buffer layer (20) is located between a passive waveguide layer (30) and the substrate (10).

3. The method for preparing a monolithic integrated light emitting chip according to claim 2, characterized in that: The length of the selective epitaxial mask pairs on both sides of the second laser region is the same as that of the second laser region, the length of the selective epitaxial mask pairs on both sides of the second amplifier region is the same as that of the second amplifier region, and the specific spacings of the two pairs of selective epitaxial mask pairs both meet the condition that the light emission wavelengths of the modulator layer (60) and the third amplifier layer (73) are 30 to 100 nm shorter than the light emission wavelengths of the second laser layer (50) and the second amplifier layer (72).

4. The method for preparing a monolithic integrated light emitting chip according to claim 3, characterized in that: The preparation method further comprises: selectively removing the contact layer (90) in other areas except the areas where the laser layer, the amplifier layer and the modulator layer (60) are located.

5. The method for preparing a monolithic integrated light emitting chip according to claim 1, characterized in that: The first laser layer (40) uses short-wavelength quantum well material InGaAsP or InGaAlAs, and the band gap wavelength is 1450 to 1510 nm; The second laser layer (50) uses a long wavelength quantum well material InGaAsP or InGaAlAs, and the band gap wavelength is 1450 to 1510 nm; The band gap wavelength of the passive waveguide layer (30) is 1100nm to 1400nm; The Bragg wavelength of the first grating layer (41) is 1450 to 1510 nm, and the Bragg wavelength of the second grating layer (51) is 1530 to 1580 nm.

6. A monolithic integrated light emitting chip manufactured by the method for manufacturing a monolithic integrated light emitting chip according to any one of claims 1 to 5, characterized in that: The monolithic integrated light emitting chip comprises: a substrate (10), a passive waveguide layer (30), a first laser layer (40), a first grating layer (41), a second laser layer (50), a second grating layer (51), a modulator layer (60), a cladding layer (80) and a contact layer (90); The passive waveguide layer (30) is formed by etching the passive waveguide layer material grown on the entire surface of the substrate (10) according to a predetermined pattern, and the passive waveguide layer (30) comprises a first input branch, a second input branch and an output branch, wherein the first input branch and the second input branch are coupled to the output branch. The first laser layer (40) is arranged on the first input branch and is located at an end far away from the coupling position, and the first grating layer (41) is arranged on the first laser layer (40); A second laser layer (50) is arranged in a selective growth region defined by a first mask pair (100) on a second input branch, the second laser layer (50) is located at an end away from a coupling position, and a second grating layer (51) is arranged on the second laser layer (50); The modulator layer (60) is arranged on the second input branch and is located between the position where the second laser layer (50) is located and the coupling position; The cladding layer (80) and the contact layer (90) are sequentially arranged on each functional layer from bottom to top.

7. The monolithic integrated light emitting chip according to claim 6, characterized in that: The monolithic integrated light emitting chip further comprises a first amplifier layer (71), a second amplifier layer (72) and a third amplifier layer (73); The first amplifier layer (71) is arranged on the first input branch and is located between the position where the first laser layer (40) is located and the coupling position, and is used to amplify the optical signal generated by the first laser layer (40); The second amplifier layer (72) is arranged in a selective growth region defined by a second mask pair (200) on the second input branch and is located between a position where the modulator layer (60) is located and a coupling position, and is used to amplify the modulated optical signal of the second laser layer (50), and the width of the region where the second amplifier layer (72) is located is limited by a second mask pair (200) with a specific spacing; The third amplifier layer (73) is arranged on the output branch and is used to amplify the optical signal coupled to the output branch from the two input branches.

8. The monolithic integrated light emitting chip according to claim 7, characterized in that: The length of the first mask pair (100) is the same as the length of the second laser layer (50), and the length of the second mask pair (200) is the same as the length of the second amplifier layer (72); The modulator layer (60) is located between the area where the second laser layer (50) is located and the area where the second amplifier layer (72) is located; The light emission wavelengths of the modulator layer (60) and the third amplifier layer (73) are shorter than the light emission wavelengths of the second laser layer (50) and the second amplifier layer (72).

9. The monolithic integrated light emitting chip according to claim 7, characterized in that: The cladding (80) includes a doped portion (81) and an undoped portion (82); The doped portion (81) is located above the first grating layer (41), the second grating layer (51), the modulator layer (60), the first amplifier layer (71), the second amplifier layer (72) and the third amplifier layer (73); the doped portion (81) is formed by p-type doping; the undoped portion (82) is located above the passive waveguide layer (30); and the contact layer (90) is arranged above the doped portion (81).

10. The monolithic integrated light emitting chip according to claim 6, characterized in that: The monolithic integrated light emitting chip further comprises a buffer layer (20), wherein the buffer layer (20) is arranged between the substrate (10) and the passive waveguide layer (30).

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