CN115912054A - Silicon-based FP laser device, integrated tunable laser and preparation method thereof - Google Patents
Silicon-based FP laser device, integrated tunable laser and preparation method thereof Download PDFInfo
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Abstract
The embodiment of the invention discloses a silicon-based FP laser device, an integrated tunable laser and a preparation method thereof. In one embodiment, the device includes a silicon substrate; a first contact layer of a first conductivity type formed on the substrate; a first electrode and a coupling cavity structure formed on the first contact layer; the coupled cavity structure comprises a lower waveguide optical limiting layer and a III-V group quantum dot active layer which are formed on a first contact layer, a first ridge type waveguide and a second ridge type waveguide which are formed on the quantum dot active layer, and an isolation groove between the first ridge type waveguide and the second ridge type waveguide, wherein each ridge type waveguide comprises an upper waveguide optical limiting layer, a second contact layer of a second conduction type and a second electrode which are sequentially formed. The implementation method has simple process, avoids the Bragg grating and secondary epitaxy technology of the traditional distributed feedback laser, can realize larger wavelength coverage range of the laser array, and is suitable for the production of low-cost large-scale silicon optical integrated chips.
Description
Technical Field
The invention relates to the technical field of optical communication semiconductor lasers. And more particularly, to a silicon-based FP laser device, an integrated tunable laser, and methods of making the same.
Background
With the advent of the big data era and the push of new 5G infrastructure, the global traffic is increasing exponentially and the demand of people on data transmission technology is increasing continuously. Optical fiber communication using photons as an information carrier is gradually a new choice for people because it has extremely low transmission loss, extremely wide spectrum bandwidth and ultra-high transmission speed, and can rapidly and economically improve the rate and capacity of information transmission.
The photonic integrated chip is a core component in optical fiber communication and mainly comprises an indium phosphide-based photonic integrated chip and a silicon-based photonic integrated chip. The silicon substrate is low in price, the size of the substrate can reach 12 inches, and the silicon substrate is compatible with a CMOS (complementary metal oxide semiconductor) process. At present, silicon materials can realize most of optoelectronic devices and have the potential of becoming an excellent optoelectronic device platform. Meanwhile, the silicon-based photoelectronic chip has the advantages of being capable of being produced in batches, high in integration level, high in yield, low in cost and easy to integrate with a microelectronic circuit in a single chip mode, and the silicon-based photoelectronic chip is benefited from mature CMOS technology. However, the absence of silicon-based light sources (lasers) has been a major factor limiting large-scale silicon photonic integrated circuits.
Research shows that III-V compound material can be directly grown on silicon in a heteroepitaxy way, so that low-cost and ultra-large-scale silicon optical monolithic integration is realized. A series of optimized Molecular Beam Epitaxy (MBE) growth technologies are utilized to inhibit the defect problem caused by mismatching of material coefficients of III-V family and a silicon substrate, a novel Quantum Dot (QD) nanostructure is reused as an active region of a laser, and researchers have successfully realized direct Epitaxy of III-V family lasers on silicon which can be used practically.
Nevertheless, the conventional si-based direct epitaxial lasers are mainly multi-longitudinal mode Fabry-perot (FP) lasers. The main reason is that single longitudinal mode lasers such as Distributed Feedback (DFB) lasers and Bragg Reflector (DBR) lasers require grating etching and secondary epitaxy technology at a nanometer level, and research on secondary epitaxy of MBE is not yet mature, and it is difficult to realize a high-quality secondary epitaxial material. In addition, the grating etching and secondary epitaxy technology is complex in process and expensive, and is not beneficial to reducing the cost of the silicon optical monolithic integrated chip.
Therefore, there is a need for an optical wavelength division multiplexing technology that can avoid grating etching and secondary epitaxy, can realize silicon-based monolithic integration of a tunable laser array with wide-range coverage wavelength at low cost, wherein each laser can transmit laser with different wavelengths, and is thus suitable for multiple optical channels.
Disclosure of Invention
The invention aims to provide a silicon-based FP laser device, an integrated tunable laser and a preparation method thereof, which aim to solve at least one of the problems in the prior art.
In order to achieve the above object, a first aspect of the present invention provides a silicon-based FP laser device, which comprises
A silicon substrate;
a first contact layer of a first conductivity type formed on the substrate;
a first electrode and a coupling cavity structure formed on the first contact layer;
the coupled cavity structure includes a lower waveguide optical confinement layer and a III-V quantum dot active layer formed on a first contact layer, and first and second ridge waveguides and an isolation groove therebetween formed on the quantum dot active layer,
each ridge waveguide includes an upper waveguide optical confinement layer, a second contact layer of a second conductivity type, and a second electrode formed in this order.
A second aspect of the invention provides a silicon-based monolithically integrated tunable laser, comprising a silicon substrate;
a first contact layer of a first conductivity type formed on the substrate;
an array of multiple FP laser devices formed on the first contact layer, each laser device comprising
A first electrode and a coupling cavity structure formed on the first contact layer;
the coupled cavity structure includes a lower waveguide optical confinement layer and a III-V quantum dot active layer formed on a first contact layer, and first and second ridge waveguides and an isolation groove therebetween formed on the quantum dot active layer,
each ridge waveguide includes an upper waveguide optical confinement layer, a second contact layer of a second conductivity type, and a second electrode formed in this order.
Preferably, the coupling cavity structures of the laser devices have the same width,
the length of the isolation groove of the laser device and the length ratio of the first ridge waveguide to the second ridge waveguide are determined by the laser wavelength of the laser device, and the width of the isolation groove is an odd multiple of one fourth of the laser wavelength.
Preferably, the doping ions of the quantum dot active layer are selected from Mn ions, P ions, or Ga ions.
Preferably, the first conductivity type is N-type, and the second conductivity type is P-type; the first electrode is a negative electrode, and the second electrode is a positive electrode.
Preferably, the quantum dot active layer comprises a plurality of periods of InAs/GaAs DWELL quantum dot active regions.
In a third aspect, the present invention provides a method for preparing a silicon-based monolithically integrated tunable laser as described above, the method comprising
Sequentially forming an N-type contact layer, a first light limiting layer, a quantum dot active layer, a second light limiting layer, a P-type contact layer and a protective layer on a silicon substrate;
carrying out ion implantation on the quantum dot active layer, wherein the quantum dot active layer of each laser device has different ion implantation doses;
photoetching the obtained structure to the position above the quantum dot active layer, and limiting a coupling cavity, a ridge waveguide and an isolation groove of each laser device;
forming a second electrode on the surface of the ridge waveguide;
forming an insulating layer on the resultant structure;
etching the obtained structure to expose the surface of the N-type contact layer and the surface of the second electrode;
and forming a first electrode on the surface of the N-type contact layer of each laser device.
Preferably, the ion implantation of the quantum dot active layer is performed in an inclined manner, so as to avoid channeling.
Preferably, the step of forming the quantum dot active layer comprises forming the InAs/GaAs DWELL quantum dot active layer for 5-8 periods.
Preferably, the length of the laser device coupling cavity isolation groove and the length ratio of the first ridge type waveguide and the second ridge type waveguide are determined through simulation based on the emission wavelength of the laser device.
The invention has the following beneficial effects:
the invention discloses a silicon-based FP laser device, an integrated tunable laser and a preparation method thereof, which utilize ion/proton implantation to regionally change the energy band gap of an active region of a quantum dot laser and utilize a multi-section coupling cavity process to realize single longitudinal mode laser output. The integrated tunable laser and the preparation method thereof have simple process, avoid the Bragg grating and the secondary epitaxy technology of the traditional distributed feedback laser, realize larger wavelength coverage range of the laser array, and are suitable for the production of large-scale silicon optical integrated chips with low cost.
Drawings
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Fig. 1 shows a schematic structural diagram of a III-V quantum dot epitaxial structure layer grown on a silicon substrate according to an embodiment of the present invention.
Fig. 2 is a schematic cross-sectional view illustrating a light emitting surface of the epitaxial wafer sample shown in fig. 1 after ion/proton implantation and annealing according to an embodiment of the present invention.
Fig. 3 is a schematic diagram illustrating a cross-sectional structure of a light-emitting surface after multi-section type coupled cavity ridge waveguide etching is performed on the sample shown in fig. 2 according to an embodiment of the present invention.
Fig. 4 is a schematic diagram illustrating a cross-sectional structure of a light emitting surface after passivation layer deposition and metal evaporation/sputtering of a P-electrode ohmic electrode are performed on the sample shown in fig. 3 according to an embodiment of the present invention.
Fig. 5 is a schematic cross-sectional structure diagram of a light emitting surface after N-type region etching and N-type ohmic electrode metal evaporation/sputtering performed on the sample shown in fig. 4 according to an embodiment of the present invention.
Fig. 6 is a schematic diagram illustrating a cross-sectional structure of a light emitting surface after P-type ohmic electrode planarization and thick gold electroplating are performed on the sample shown in fig. 5 according to an embodiment of the present invention. The figure is a schematic diagram of the final structure of the silicon-based monolithically integrated laser array.
Fig. 7 shows a three-dimensional schematic diagram of a silicon-based monolithically integrated laser array provided by an embodiment of the present invention.
Detailed Description
In order to more clearly illustrate the present invention, the present invention will be further described with reference to the following examples and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.
The existing single longitudinal mode lasers such as a distributed feedback laser, a Bragg reflector laser and the like all need grating etching and secondary epitaxy technology at a nanometer level, and the research of MBE on secondary epitaxy is not mature, so that high-quality secondary epitaxy materials are difficult to realize. In addition, the grating etching and secondary epitaxy technology is complex in process and expensive, and is not beneficial to reducing the cost of the silicon optical monolithic integrated chip. Therefore, it is urgently needed to provide an optical wavelength division multiplexing technology which can avoid grating etching and secondary epitaxy technology, can realize silicon-based monolithic integration of laser arrays covering a large range of wavelengths and being tunable at low cost, wherein each laser can send laser with different wavelengths, so that the optical wavelength division multiplexing technology is suitable for multiple optical channels.
The invention provides a silicon-based FP laser device, which comprises a silicon substrate; a first contact layer of a first conductivity type formed on the substrate; a first electrode and a coupling cavity structure formed on the first contact layer; the coupled cavity structure comprises a lower waveguide optical limiting layer and a III-V compound quantum dot active layer which are formed on a first contact layer, a first ridge type waveguide and a second ridge type waveguide which are formed on the quantum dot active layer, and an isolation groove between the first ridge type waveguide and the second ridge type waveguide, wherein each ridge type waveguide comprises an upper waveguide optical limiting layer, a second contact layer of a second conduction type and a second electrode which are sequentially formed. As a preferred embodiment, the laser device further includes a thick gold plating layer formed on the second electrode.
The invention further provides a silicon-based monolithic integrated tunable laser, which comprises a silicon substrate; a first contact layer of a first conductivity type formed on the substrate; an array of a plurality of FP laser devices formed on the first contact layer, each laser device comprising a first electrode and a coupling cavity structure formed on the first contact layer; the coupled cavity structure comprises a lower waveguide optical confinement layer and a III-V quantum dot active layer which are formed on a first contact layer, a first ridge waveguide and a second ridge waveguide which are formed on the quantum dot active layer, and an isolation groove between the first ridge waveguide and the second ridge waveguide, wherein each ridge waveguide comprises an upper waveguide optical confinement layer, a second contact layer of a second conduction type and a second electrode which are sequentially formed. As a preferred embodiment, the coupling cavity structures of the laser devices have the same width, the length of the isolation groove of the laser device and the length ratio of the first ridge waveguide and the second ridge waveguide are determined by the laser wavelength of the laser device, and the width of the isolation groove is an odd multiple of one fourth of the laser wavelength. The width of the ridge waveguide is about 2-5 μm to ensure single transverse mode lasing of the device. The doping ions of the quantum dot active layer are selected from Mn ions, P ions or Ga ions. The first conduction type is a P type, and the second conduction type is an N type; the first electrode is a negative electrode, and the second electrode is a positive electrode. The quantum dot active layer includes multiple periods of, for example, inAs/GaAs DWELL quantum dot active regions.
The invention further provides a preparation method of the silicon-based monolithic integration tunable laser, which comprises the steps of sequentially forming an N-type contact layer, a first optical limiting layer, a quantum dot active layer, a second optical limiting layer, a P-type contact layer and a protective layer on a silicon substrate; carrying out ion implantation on the quantum dot active layer, wherein the quantum dot active layer of each laser device has different ion implantation doses; photoetching the obtained structure above the quantum dot active layer, and limiting a coupling cavity, a ridge waveguide and an isolation groove of each laser device; forming a second electrode on the surface of the ridge waveguide; forming an insulating layer on the resultant structure; etching the obtained structure to expose the surface of the N-type contact layer and the surface of the second electrode; and forming a first electrode on the surface of the N-type contact layer of each laser device. As a preferred embodiment, the ion implantation to the quantum dot active layer is performed by tilt implantation, and the tilt angle is, for example, 7 ° away from the normal direction of the sample surface, so as to avoid channeling. The step of forming the quantum dot active layer comprises forming the InAs/GaAs DWELL quantum dot active layer for 5-8 periods. In the invention, based on the emission wavelength of the laser device, the length of the coupling cavity isolation groove of the laser device and the length ratio of the first ridge type waveguide to the second ridge type waveguide are determined through simulation.
The laser and the method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.
The invention discloses a method for preparing a silicon-based monolithic integrated laser array, which comprises the steps of growing a III-V group compound quantum dot heterojunction on a silicon substrate, wherein the heterojunction comprises a P-type contact layer, an active region and an N-type contact layer, carrying out ion implantation and annealing treatment on the active region of each laser with different energies, forming a multi-section coupling cavity ridge waveguide by using an etching technology, depositing a passivation layer of the multi-section coupling cavity ridge waveguide, and exposing the P-type contact layer by using patterning treatment and a top windowing technology to form a positive electrode; forming a negative electrode on the N-type contact layer; carrying out thick gold electroplating after the positive electrode is subjected to planarization treatment; and post-processing the silicon substrate.
In one possible implementation, the heterojunction further comprises a III-V compound buffer layer formed on the substrate, an N-type optical confinement layer and a P-type optical confinement layer formed on the N-type contact layer.
In one possible implementation, the active region includes multiple periods of InAs/GaAs DWELL quantum dot active regions.
As shown in FIG. 1, a III-V group quantum dot epitaxial structure layer including, but not limited to, III-V buffer layer 2,N type doped GaAs contact layer 3,N type doped AlGaAs optical confinement layer 4,5-8 cycles of InAs/GaAs DWELL quantum dot active region 5,P type doped AlGaAs optical confinement layer 6,P type highly doped GaAs contact layer 7 is epitaxially grown on silicon substrate 1 using MBE.
In one possible implementation, the ion implantation on the active region comprises forming 50nm-100nm of SiO on the surface of the epitaxial heterojunction 2 Or a SiN dielectric layer, and reserving the dielectric layer of each ridge waveguide to be subjected to ion implantation by utilizing patterned photoetching and etching.
In one possible implementation, the implanted ions are selected from Mn ions, P ions, protons, and Ga ions injected using a focused ion beam; wherein the ion beams are all implanted at 7 deg. from the heterojunction surface normal.
As shown in FIG. 2, a layer of SiO 50nm-100nm is evaporated on the surface of the epitaxial structure layer 2 the/SiN is used as a surface protective cover layer of the epitaxial structure layer, namely the dielectric layer 100, so as to prevent the surface of the epitaxial structure layer from being damaged in the ion/proton implantation process; similarly, the dielectric layer 100 may generate stress due to a thermal expansion coefficient different from that of the epitaxial material in a subsequent annealing process, thereby promoting a quantum dot doping effect, increasing a change of an energy band gap, and realizing a peak shift exceeding 80 MeV. In addition, in the present embodiment, a non-destructive dielectric layer and cap layer hybrid can be usedThe technology utilizes dielectric layers with different thermal expansion coefficients to generate different stresses on an epitaxial structure layer so as to change the energy band gap of an active region.
After the dielectric layer 100 is evaporated, pattern photoetching and etching are carried out, and only the dielectric layer of the laser ridge waveguide part needing ion/proton injection is reserved. And then, carrying out ion/proton implantation on the epitaxial structure layer, adjusting the required implantation energy according to different ion/proton types, and carrying out analog simulation on the implantation energy to ensure that the implantation depth can reach the active region part of the quantum dot, but the excessive depth is required to be avoided so as to avoid influencing the light-emitting quality. Optional particle species include Mn ions, P ions, and protons, and Ga ions and the like can also be injected using a Focused Ion Beam (FIB). For example, when Mn ions are selected for injection, mn ions can be used in a dosage range of 1X 10 13 cm -3 -1×10 15 cm -3 . To avoid channeling, the ion beam is implanted at an angle of 7 ° from the normal to the sample surface. In this embodiment, different degrees of tuning of the active region can be achieved by implanting different ion/proton doses in different regions 510, 520, 530 and 540 (i.e., each laser ridge waveguide region).
The ion/proton injection is followed by a Rapid Thermal Annealing (RTA) of the epitaxial structure layer to activate the implanted ions/protons for active region intermixing. Also, a short time of high temperature anneal may also aid in the restoration of the damaged lattice. The annealing time and temperature need to be adjusted according to the type of the implanted particles. For example, when Mn ion implantation is selected for injection, the annealing temperature can be selected in the range of 600-800 ℃ for 30-60s. It is noted that too high temperatures may cause InAs/GaAs QDs to fail, thus requiring careful use of high temperatures. And after the annealing is finished, removing the sample protective cover layer by using hydrofluoric acid and a dry etching process.
In a possible implementation manner, the forming of the multi-section coupling cavity ridge waveguide by using the etching technology includes that the width of the multi-section coupling cavity ridge waveguide is 2um-5um, the etching stop depth is higher than the active region by 100nm-200nm, and the coupling cavity, the ridge waveguide and the isolation groove of each laser device are limited.
In a possible implementation manner, the forming the multi-section coupling cavity ridge waveguide by using the etching technology further includes performing isolation by using a plurality of vertically formed air slots by using the multi-section coupling cavity, wherein the length of the air slot is an odd multiple of a quarter of the laser wavelength.
As shown in fig. 3, laser Coupled cavity ridge waveguide etching is performed using photolithography and ICP (Inductively Coupled Plasma) etching techniques. The width of the ridge waveguide is about 2-5 μm to ensure single transverse mode laser of the device, and the etching stop depth is set to be 100-200nm higher than the active region to ensure that the etching does not contact the quantum dot active region.
The multi-section coupling cavity technology in this embodiment adopts a two-section coupling cavity. The design idea of the coupling cavity is to introduce vernier effect and control the output wavelength of the laser by changing the refractive index difference between the cavities. Therefore, the proportion of the two coupling cavities and the length of the air slot need to be simulated and calculated, and then preparation is determined. For example, a transmission matrix algorithm may be selected for the design. In this embodiment, the coupling cavity ratio is designed according to different target laser wavelengths, and in addition, the width of the air slot needs to satisfy an odd multiple of one quarter of the lasing wavelength.
In one possible implementation, the positive electrodes of each coupling cavity are not connected, and the resistivity of the positive electrodes is preferably greater than 2000 Ω.
In this embodiment, the two positive electrodes on the two ridge waveguides of the coupling cavity are not connected, and the resistivity of the two electrodes is greater than 2000 Ω, so that the current is independently controlled to realize the function of tuning the wavelength.
As shown in fig. 4, for the etched ridge waveguide dielectric layer, the material of the dielectric layer is SiO 2 and/SiN. Patterning and top-level windowing are then performed to achieve the device's insulating layer structures 901, 902, 903 and 904. The top layer of the insulating layer is windowed to expose the P-type contact layers 710, 720, 730, and 740 of the ridge waveguide. Then, the P- type electrodes 810, 820, 830 and 840 are evaporated on the P-type contact layers 710, 720, 730 and 740 by photolithography, electron beam sputtering or magnetron sputtering, and then RTA treatment is performed to form low resistanceIs used for ohmic contact. It is noted that the electrodes of the two coupling cavities are not connected here.
As shown in fig. 5, photolithography and ICP etching are used to reach the epitaxial layer N-type contact layer 3, negative electrodes 101, 102, 103 and 104 are vapor-deposited on the N-type contact layer 3 using electron beam sputtering or magnetron sputtering, and finally RTP processing is performed to form low-resistance ohmic contact.
As shown in fig. 6, a planarization material spin coating, curing bake, and planarization etch are performed. The laser anodes are subjected to thick gold plating layers 910, 920, 930 and 940 using photolithography and plating techniques.
In one possible implementation, the post-processing of the silicon substrate includes thinning and cleaving, wherein the thinning includes thinning the silicon substrate to 200-120 um using a grinder.
The silicon substrate is thinned to 200-120 μm by a grinder, thereby reducing the influence of thermal effects on the device.
Fig. 7 is a three-dimensional perspective view of a laser array consisting of four silicon substrate directly grown lasers (S1, S2, S3 and S4). Each laser employs a two-segment coupled cavity structure with two FP cavities separated by etched air slots (601, 602, 603, and 604). Each laser contains two independent P-type electrodes: 911 and 912 are the electrodes of laser S1; 921 and 922 are the electrodes of laser S2; 931 and 932 are the electrodes of laser S3; 941 and 942 are the electrodes of the laser S4. According to the cavity theory, the width of the air slot must be equal to an odd multiple of one quarter of the laser wavelength. The length proportion of the two cavities is changed by adjusting the position of the etched air groove, and the refractive index of the material is changed by changing the current injected by the two independent electrodes (such as 911 and 912), the resonance peak of the two cavities is controlled, and the mode selection of the laser in a certain range is realized. In addition, the active region of each laser is subjected to ion/proton implantation and annealing treatment with different energy, so that the quantum dot gain spectrum curve of each laser is changed. Therefore, a group of tunable single longitudinal mode laser arrays with different lasing wavelengths can be obtained.
According to the method for silicon-based monolithic integration of the laser array, the energy band gap of the active region of a quantum dot laser is changed by ion/proton implantation regionally, single longitudinal mode laser output is realized by utilizing a multi-section coupling cavity process, the manufacturing process is simple, bragg gratings and secondary epitaxial technology of the traditional distributed feedback laser are avoided, the large wavelength coverage range of the laser array can be realized, and the method is suitable for low-cost large-scale silicon optical chip production.
Another embodiment of the invention provides a silicon-based monolithically integrated laser array device comprising growing a III-V quantum dot heterojunction on a silicon substrate, the heterojunction comprising an active region, a P-type contact layer, and an N-type contact layer; forming a multi-section coupling cavity ridge waveguide on the active region; forming a positive electrode on a P-type contact layer of the multi-section coupling cavity ridge waveguide; forming a negative electrode on the N-type contact layer; forming a thick gold plating layer after the positive electrode planarization treatment; and forming a post-integrated laser array after the silicon substrate is subjected to post-processing.
The embodiment discloses a silicon-based monolithic integrated laser array device, which realizes the band gap adjustment of an active region of a laser by using ion/proton implantation with different doses, and realizes single longitudinal mode laser lasing by combining a coupling cavity technology, thereby realizing multi-channel light source emission without high cost and technically complicated grating etching and secondary epitaxy technology.
In the description of the present invention, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present invention. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
It should also be noted that, in the description of the present invention, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the invention and are not intended to limit the embodiments of the present invention, and that various other modifications and variations can be made by one skilled in the art in light of the above description.
Claims (10)
1. A silicon-based FP laser device is characterized in that the device comprises
A silicon substrate;
a first contact layer of a first conductivity type formed on the substrate;
a first electrode and a coupling cavity structure formed on the first contact layer;
the coupled cavity structure includes a lower waveguide optical confinement layer and a III-V quantum dot active layer formed on a first contact layer, and first and second ridge waveguides and an isolation groove therebetween formed on the quantum dot active layer,
each ridge waveguide includes an upper waveguide optical confinement layer, a second contact layer of a second conductivity type, and a second electrode formed in this order.
2. A silicon-based monolithic integrated tunable laser, characterized in that the laser comprises
A silicon substrate;
a first contact layer of a first conductivity type formed on the substrate;
an array of multiple FP laser devices formed on the first contact layer, each laser device comprising
A first electrode and a coupling cavity structure formed on the first contact layer;
the coupled cavity structure comprises a lower waveguide optical confinement layer and a III-V quantum dot active layer formed on a first contact layer, and a first ridge waveguide and a second ridge waveguide formed on the quantum dot active layer and an isolation groove therebetween,
each ridge waveguide includes an upper waveguide optical confinement layer, a second contact layer of a second conductivity type, and a second electrode formed in this order.
3. The silicon-based monolithically integrated tunable laser of claim 2,
the coupling cavity structures of the laser devices have the same width,
the length of the isolation groove of the laser device and the length ratio of the first ridge waveguide and the second ridge waveguide are determined by the laser wavelength of the laser device, and the width of the isolation groove is an odd multiple of one fourth of the laser wavelength.
4. The silicon-based monolithically integrated tunable laser of claim 2, wherein doping ions of the quantum dot active layer are selected from Mn ions, P ions, or Ga ions.
5. The silicon-based monolithically integrated tunable laser of claim 2, wherein the first conductivity type is N-type and the second conductivity type is P-type; the first electrode is a negative electrode, and the second electrode is a positive electrode.
6. The silicon-based monolithically integrated tunable laser of claim 2, wherein said quantum dot active layer comprises multiple periods of InAs/GaAsDWELL quantum dot active regions.
7. A method of fabricating a silicon-based monolithically integrated tunable laser according to any of claims 2-6, comprising
Sequentially forming an N-type contact layer, a first optical limiting layer, a quantum dot active layer, a second optical limiting layer, a P-type contact layer and a protective layer on a silicon substrate;
carrying out ion implantation on the quantum dot active layer, wherein the quantum dot active layer of each laser device has different ion implantation doses;
photoetching the obtained structure above the quantum dot active layer, and limiting a coupling cavity, a ridge waveguide and an isolation groove of each laser device;
forming a second electrode on the surface of the ridge waveguide;
forming an insulating layer on the resultant structure;
etching the obtained structure to expose the surface of the N-type contact layer and the surface of the second electrode;
and forming a first electrode on the surface of the N-type contact layer of each laser device.
8. The method for manufacturing the silicon-based monolithic tunable laser as claimed in claim 7, wherein the ion implantation of the quantum dot active layer is performed by tilt implantation to avoid channeling.
9. The method of claim 7, wherein the step of forming the quantum dot active layer comprises forming a 5-8 period InAs/GaAs DWELL quantum dot active layer.
10. The method of claim 7, wherein the length of the isolation trench of the coupling cavity of the laser device and the length ratio of the first ridge waveguide to the second ridge waveguide are determined by simulation based on the emission wavelength of the laser device.
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