Tunable electro-absorption modulated laser and preparation method thereof

Abstract

The present invention provides a tunable electro-absorption modulated laser, comprising: a first modulator region, a first front grating region, a first gain region, a first phase region, a rear grating region, a second phase region, a second gain region, a second front grating region and a second modulator region, which are located on the same substrate, have the same height and are sequentially bonded, wherein the first gain region and the second gain region both comprise a first lower waveguide layer, a first active layer and a first upper waveguide layer in a preset order, and the first lower waveguide layer is formed on the substrate; the first modulator region and the second modulator region both comprise a second lower waveguide layer, a second active layer and a second upper waveguide layer in a preset order, and the second lower waveguide layer is formed on the substrate; the first front grating region, the second front grating region, the rear grating region, the first phase region and the second phase region all comprise a passive layer, and the passive layer is formed on the substrate, and the first front grating region, the second front grating region and the rear grating region form a grating structure on the passive layer, and the grating structure comprises a sampled grating.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor optoelectronic integrated devices, and in particular, relates to a tunable electro-absorption modulated laser and a preparation method thereof. Background Art

[0002] With the rapid development of technologies such as mobile data networks and cloud computing, the communication capacity of data centers has shown explosive growth. Future data centers will require transmission solutions with higher capacity than 100G Ethernet. Therefore, higher requirements are placed on the wavelength coverage and rate of tunable laser optical emission chips.

[0003] The wavelength tuning range of traditional tunable lasers is about 10nm, while directly modulated lasers have limited bandwidth. In addition, traditional modulated lasers emit laser light from one end and cannot achieve dual-end dual-modulation light output. Summary of the invention

[0004] In view of this, in order to obtain a larger wavelength tuning range (wavelength greater than 40nm), realize double-end dual-modulation light output, and improve the integration of light emitting chips, the present invention provides a tunable electro-absorption modulated laser and a preparation method thereof, providing a new light emitting chip solution for optical communication systems.

[0005] In order to achieve the above-mentioned object, the present invention provides a tunable electro-absorption modulated laser, comprising: a first modulator region, a first front grating region, a first gain region, a first phase region, a back grating region, a second phase region, a second gain region, a second front grating region and a second modulator region, which are located on the same substrate, have the same height and are sequentially attached, wherein:

[0006] The first gain region and the second gain region each include a first lower waveguide layer, a first active layer and a first upper waveguide layer in a preset order, wherein the first lower waveguide layer is formed on a substrate;

[0007] The first modulator region and the second modulator region each include a second lower waveguide layer, a second active layer, and a second upper waveguide layer in a preset order, wherein the second lower waveguide layer is formed on a substrate;

[0008] The first front grating region, the second front grating region, the rear grating region, the first phase region and the second phase region all include a passive layer, the passive layer is formed on a substrate, the first front grating region, the second front grating region and the rear grating region form a grating structure on the passive layer, and the grating structure includes a sampling grating.

[0009] According to an embodiment of the present invention, the first active layer and the second active layer are both multi-quantum well active layers, the structure of the multi-quantum well active layer includes a plurality of alternately stacked barrier layers and well layers, the thickness of each barrier layer is 9 nm, the thickness of each well layer is 5 nm, and the multi-quantum well material is InGaAsP or InGaAlAs.

[0010] According to an embodiment of the present invention, the first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region all include a cladding and an electrical contact layer and a p-side electrode separated by an electrical isolation groove.

[0011] According to an embodiment of the present invention, the electrical contact layer and the p-side electrode are sequentially arranged on the cladding; the cladding of the first gain region and the second gain region is formed on the first upper waveguide layer; the cladding of the first modulator region and the second modulator region is formed on the second upper waveguide layer; the cladding of the first front grating region, the second front grating region, the first phase region, the second phase region and the back grating region is formed on the passive layer; and the n-side electrode is arranged on the lower surface of the substrate.

[0012] According to an embodiment of the present invention, the cladding layer and the electrical contact layer are inverted shallow ridge waveguide structures, and the side cross-section of the inverted shallow ridge waveguide structure is in an inverted trapezoidal shape.

[0013] According to an embodiment of the present invention, helium ions are implanted into the electrical isolation trench between the electrical contact layer and the p-side electrode.

[0014] According to an embodiment of the present invention, the sampling period length of the sampling gratings in the first front grating area and the second front grating area is smaller than the sampling period length of the sampling grating in the rear grating area; the sampling period number of the sampling gratings in the first front grating area and the second front grating area is smaller than the sampling period number of the sampling grating in the rear grating area.

[0015] The present invention also provides a method for preparing a tunable electro-absorption modulated laser, comprising:

[0016] sequentially growing a first lower waveguide layer, a first active layer and a first upper waveguide layer on a substrate;

[0017] Etching away a portion of the first lower waveguide layer, the first active layer, and the first upper waveguide layer to expose the substrate, so that the remaining portion of the first lower waveguide layer, the first active layer, and the first upper waveguide layer that are not etched away are the first gain region and the second gain region;

[0018] sequentially growing a second lower waveguide layer, a second active layer and a second upper waveguide layer on the substrate corresponding to the first lower waveguide layer, the first active layer and the first upper waveguide layer with partial regions etched away;

[0019] Etching away a portion of the second lower waveguide layer, the second active layer, and the second upper waveguide layer to expose the substrate, so that the remaining portion of the second lower waveguide layer, the second active layer, and the second upper waveguide layer that are not etched away are the first modulator region and the second modulator region;

[0020] A passive layer is formed on the substrate corresponding to the second lower waveguide layer, the second active layer and the second upper waveguide layer, wherein the passive layer is flush with the first upper waveguide layer and the second upper waveguide layer, and the passive layer is divided into a first front grating region, a first phase region, a rear grating region, a second phase region and a second front grating region;

[0021] A grating structure is prepared in a partial region of the passive layer, wherein the grating structure is a sampled grating.

[0022] According to an embodiment of the present invention, the above preparation method further comprises:

[0023] sequentially growing a cladding layer and an electric contact layer on the first upper waveguide layer, the second upper waveguide layer and the passive layer;

[0024] Etching an electrical isolation groove on the electrical contact layer so that the electrical contact layers of the first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region are arranged at intervals;

[0025] Preparing a p-side electrode on the electrical contact layer of the first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region;

[0026] The substrate is thinned, and an n-side electrode is prepared on the lower surface of the substrate.

[0027] According to an embodiment of the present invention, the material of the passive layer is InGaAsP or InGaAlAs bulk material.

[0028] According to an embodiment of the present invention, a tunable electro-absorption modulated laser is integrated by sharing a rear grating region and adopting a sampled grating, so that the tunable electro-absorption modulated laser can achieve the effect of doubling the speed and wavelength tuning range of the laser by means of the vernier effect of the sampling gratings before and after the laser, and realize double-end dual-modulation laser emission by sharing the rear grating region, while also reducing the power consumption of the rear grating region, thereby providing a new solution for optical communication systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The schematic diagram of the structure of a tunable electro-absorption modulated laser according to an embodiment of the present invention is shown;

[0030] Figure 2A flow chart schematically shows a method for preparing a tunable electro-absorption modulated laser according to an embodiment of the present invention;

[0031] Figure 3 A front cross-sectional view schematically shows a structure after a first lower waveguide layer, a first active layer and a first upper waveguide layer are grown on a substrate according to an embodiment of the present invention;

[0032] Figure 4 A schematic diagram shows a top view of a structure after a mask pattern is prepared according to an embodiment of the present invention;

[0033] Figure 5 A front cross-sectional view after etching according to an embodiment of the present invention is schematically shown;

[0034] Figure 6 A front cross-sectional view schematically shows a structure after a second lower waveguide layer, a second active layer and a second upper waveguide layer are grown on a substrate according to an embodiment of the present invention;

[0035] Figure 7 A schematic top view of a structure after a mask pattern is prepared according to another embodiment of the present invention is shown;

[0036] Figure 8 A front cross-sectional view schematically shows a structure after etching according to another embodiment of the present invention;

[0037] Fig. 9 Schematically showing a front cross-sectional view of a structure after a passive layer is grown according to an embodiment of the present invention;

[0038] Fig.10 A front cross-sectional view schematically shows a structure after preparing a grating structure, a cladding layer and an electrical contact layer according to an embodiment of the present invention;

[0039] Fig.11 Schematically showing a side cross-sectional view of an inverted shallow ridge waveguide structure manufactured according to an embodiment of the present invention;

[0040] Fig.12 The front cross-sectional view of the structure after etching the electrical isolation trench and implanting helium ions according to an embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0041] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0042] Electro-absorption modulated lasers have become the preferred device for data center light sources due to their advantages such as high speed, low chirp, low insertion loss, and electrical tunability. In electro-absorption modulated lasers, gratings are evenly distributed in the entire distributed feedback laser area, and the mode selection characteristics of the gratings are used to achieve single longitudinal mode output. The electro-absorption modulator performs electro-absorption modulation on the laser emitted by the distributed feedback laser, and outputs the modulated laser signal through the end face of the electro-absorption modulator.

[0043] However, the conventional electro-absorption modulated laser can only emit laser at one end, and cannot realize double-end dual-modulation laser emission, which reduces the integration of the light emitting chip, the light emission rate and the wavelength tuning performance. Therefore, the present invention provides a tunable electro-absorption modulated laser to solve at least one of the above problems.

[0044] Figure 1 The schematic diagram of the structure of a tunable electro-absorption modulated laser according to an embodiment of the present invention is shown schematically.

[0045] like Figure 1 As shown, the tunable electro-absorption modulated laser may include: a first modulator region 1, a first front grating region 2, a first gain region 3, a first phase region 4, a rear grating region 9, a second phase region 8, a second gain region 7, a second front grating region 6 and a second modulator region 5, which are located on the same substrate 10, are at the same height and are sequentially bonded.

[0046] According to the embodiment of the present invention, the first gain region 3 and the second gain region 7 each include a first lower waveguide layer 11 , a first active layer 12 and a first upper waveguide layer 13 in a preset order, and the first lower waveguide layer 11 is formed on a substrate 10 .

[0047] According to an embodiment of the present invention, the first modulator region 1 and the second modulator region 5 each include a second lower waveguide layer 15 , a second active layer 16 and a second upper waveguide layer 17 in a predetermined order. The second lower waveguide layer 15 is formed on the substrate 10 .

[0048] According to an embodiment of the present invention, the first front grating region 2, the second front grating region 6, the rear grating region 9, the first phase region 4 and the second phase region 8 all include a passive layer 19, and the passive layer 19 is formed on a substrate 10. The first front grating region 2, the second front grating region 6 and the rear grating region 9 form a grating structure 20 on the passive layer 19. The grating structure may include a sampled grating with a uniform periodic distribution.

[0049] According to an embodiment of the present invention, the sampling period length of the sampling gratings of the first front grating area 2 and the second front grating area 6 is smaller than the sampling period length of the sampling grating of the rear grating area 9; the number of sampling periods of the sampling gratings of the first front grating area 2 and the second front grating area 6 is smaller than the number of sampling periods of the rear grating area 9.

[0050] According to an embodiment of the present invention, the wavelength fine-tuning of the first phase region and the second phase region can be combined to change the laser phase, and the vernier effect of the laser sampling grating can be used to obtain a wavelength tuning range greater than 40nm.

[0051] According to an embodiment of the present invention, the length range of the first modulator zone and the second modulator zone is 0 to 300 μm, the length range of the first front grating zone and the second front grating zone is 0 to 200 μm, the length range of the first gain zone and the second gain zone is 0 to 500 μm, the length range of the first phase zone and the second phase zone is 0 to 300 μm, and the length range of the rear grating zone is 0 to 1000 μm.

[0052] According to an embodiment of the present invention, the first modulator region 1, the first front grating region 2, the first gain region 3, the first phase region 4, the back grating region 9, the second phase region 8, the second gain region 7, the second front grating region 6 and the second modulator region 5 all include: a cladding 21 and an electrical contact layer 22 and a p-side electrode 24 separated by an electrical isolation groove 26.

[0053] According to an embodiment of the present invention, the cladding 21 of the first gain region 3 and the second gain region 7 is formed on the first upper waveguide layer 13; the cladding 21 of the first modulator region 1 and the second modulator region 5 is formed on the second upper waveguide layer 17; the cladding 21 of the first front grating region 2, the second front grating region 6, the first phase region 4, the second phase region 8 and the back grating region 9 is formed on the passive layer.

[0054] According to the embodiment of the present invention, the lower surface of the substrate 10 is provided with an n-side electrode 25 .

[0055] According to an embodiment of the present invention, the wavelength of the modulator region is 20 to 100 microns shorter than the wavelength of the gain region, and the band gap wavelengths of the front and rear grating regions and the phase region are 90 to 200 nm shorter than the wavelength of the gain region. It should be noted that the modulator region includes a first modulator region and a second modulator region, the gain region includes a first gain region 3 and a second gain region 7, and the front grating region includes a first front grating region and a second front grating region.

[0056] According to an embodiment of the present invention, the first active layer 12 and the second active layer 16 are both multi-quantum well active layers. The structure of the multi-quantum well active layer may include a plurality of alternately stacked barrier layers and well layers. For example, the structure of the multi-quantum well active layer may include 5 compressively strained well layers and 6 tensile strained barrier layers, each barrier layer may have a thickness of 9 nm, and each well layer may have a thickness of 5 nm. The multi-quantum well material may be InGaAsP or InGaAlAs.

[0057] According to an embodiment of the present invention, the band gap wavelength of the multi-quantum well material is smaller than 10-100 nm of the laser emission wavelength.

[0058] According to the embodiments of the present invention, using InGaAsP or InGaAlAs material as the multi-quantum well material can improve the temperature characteristics and high-frequency characteristics of the tunable electro-absorption modulated laser, so that the tunable electro-absorption modulated laser can operate in a larger range and at a higher modulation frequency.

[0059] According to the embodiment of the present invention, the first active layer 12 may be sandwiched between the first lower waveguide layer 11 and the first upper waveguide layer 12 to form a sandwich structure; the second active layer 16 may be sandwiched between the second lower waveguide layer 15 and the second upper waveguide layer 17 to form a sandwich structure. It should be noted that the structure of the first active layer, the first lower waveguide layer and the first upper waveguide layer is not specifically limited, and the structure of the second active layer, the second lower waveguide layer and the second upper waveguide layer is not specifically limited.

[0060] According to an embodiment of the present invention, the cladding 21 and the electrical contact layer 22 of the first modulator region 1, the first front grating region 2, the first gain region 3, the first phase region 4, the back grating region 9, the second phase region 8, the second gain region 7, the second front grating region 6 and the second modulator region 5 are an inverted shallow ridge waveguide structure, and the side interface of the inverted shallow ridge waveguide structure is an inverted trapezoidal structure.

[0061] According to an embodiment of the present invention, helium ions 23 are injected into the cladding 21 through the electrical isolation groove 26 of the electrical contact layer 22 and the p-side electrode 24, so as to form electrical isolation between the various functional areas and effectively prevent the accumulation of materials at the docking interface during the docking growth between the areas, thereby reducing light loss and light reflection at the interface.

[0062] According to an embodiment of the present invention, a tunable electro-absorption modulated laser is integrated by sharing a rear grating region and adopting a sampled grating, so that the tunable electro-absorption modulated laser can achieve the effect of doubling the speed and wavelength tuning range of the laser by means of the vernier effect of the sampling gratings before and after the laser, and realize double-end dual-modulation laser emission by sharing the rear grating region, while also reducing the power consumption of the rear grating region, thereby providing a new solution for optical communication systems.

[0063] The present invention also provides a method for preparing the above-mentioned tunable electro-absorption modulated laser. For example, Figure 2 The flowchart of the method for preparing a tunable electro-absorption modulated laser according to an embodiment of the present invention is schematically shown.

[0064] like Figure 2 As shown, the preparation method includes operations S210 to S260.

[0065] In operation S210 , a first lower waveguide layer 11 , a first active layer 12 , and a first upper waveguide layer 13 are sequentially grown on a substrate 10 .

[0066] According to an embodiment of the present invention, the substrate 10 may be an indium phosphide substrate, and an InGaAsP first lower waveguide layer 11, a first active layer 12, and a first upper waveguide layer 13 may be sequentially grown on the substrate 10 by using a metal organic compound vapor deposition method (MOVCD). The band gap wavelength of the first lower waveguide layer 11 is 1200 nm, the band gap wavelength of the first active layer 12 is 1550 nm, and the band gap wavelength of the first upper waveguide layer 13 is 1200 nm.

[0067] According to an embodiment of the present invention, process parameters for growing the first lower waveguide layer 11, the first active layer 12 and the first upper waveguide layer 13 on the substrate 10 by using an organic metal compound vapor deposition method may be: a growth temperature of 680° C., a growth pressure of 100 mbar, a thickness of the first lower waveguide layer 11 and the first upper waveguide layer 13 are both 90 nm, and a structure of the first active layer 12 may be a plurality of multi-quantum well active layer structures, which may include 5 compressive strain well layers and 6 tensile strain barrier layers, each well layer having a thickness of 5 nm, and each barrier layer having a thickness of 9 nm.

[0068] For example, Figure 3 The diagram schematically shows a front cross-sectional view of a structure after a first lower waveguide layer, a first active layer and a first upper waveguide layer are grown on a substrate according to an embodiment of the present invention.

[0069] like Figure 3 As shown, the first modulator region 1, the first front grating region 2, the first gain region 3, the first phase region 4, the rear grating region 9, the second phase region 8, the second gain region 7, the second front grating region 6 and the second modulator region 5 are distinguished by dotted lines.

[0070] In operation S220, a portion of the first lower waveguide layer 11, the first active layer 12, and the first upper waveguide layer 13 is etched away to expose the substrate 10, so that the remaining portion of the first lower waveguide layer 11, the first active layer 12, and the first upper waveguide layer 13 that is not etched away is the first gain region 3 and the second gain region 7.

[0071] According to an embodiment of the present invention, operation S220 may include:

[0072] Operation S220-1: growing a 150 nm thick SiO2 layer on the first upper waveguide layer 13, and using a 1 μm thick photoresist mask, etching out 30 μm wide SiO2 strip structures 14 of the first gain region 3 and the second gain region 7 using a buffered oxide etching solution (BOE).

[0073] For example, Figure 4 The top view of the structure after preparing the mask pattern according to an embodiment of the present invention is schematically shown. Figure 4 As shown, the mask pattern 14 is a stripe structure.

[0074] Operation S220-2: Reactive ion etching (RIE) is used to etch away a portion of the first lower waveguide layer 11, the first active layer 12, and the first upper waveguide layer 13 to expose the substrate 10, so that the remaining portions of the first lower waveguide layer 11, the first active layer 12, and the first upper waveguide layer 13 that are not etched away are the first gain region and the second gain region. For example, Figure 5 The front cross-sectional view after etching according to an embodiment of the present invention is schematically shown.

[0075] like Figure 5 As shown, the first lower waveguide layer 11, the first active layer 12 and the first upper waveguide layer 13 in partially etched areas may be materials from which the first modulator region 1, the first front grating region 2, the first phase region 4, the rear grating region 9, the second phase region 8, the second front grating region 6 and the second modulator region 5 are etched, and the first lower waveguide layer 11, the first active layer 12 and the first upper waveguide layer 13 in partially etched areas are used to prepare the first gain region 3 and the second gain region 7.

[0076] According to an embodiment of the present invention, by using freezing-point H2SiO4 and H2O2 solutions to etch the remaining materials on the substrate of the first modulator region 1, the first front grating region 2, the first phase region 4, the rear grating region 9, the second phase region 8, the second front grating region 6 and the second modulator region 5, and cleaning the substrate with deionized water, a front cross-sectional view of the structure obtained in this step is obtained, as shown in FIG. Figure 5 shown.

[0077] In operation S230, a second lower waveguide layer 15, a second active layer 16 and a second upper waveguide layer 17 are sequentially grown on the substrate 10 corresponding to the first lower waveguide layer 11, the first active layer 12 and the first upper waveguide layer 13 where parts of the first lower waveguide layer 11, the first active layer 12 and the first upper waveguide layer 13 are etched away.

[0078] According to an embodiment of the present invention, MOVCD is used to sequentially grow the second lower waveguide layer 15, the second active layer 16, and the second upper waveguide layer 17 on the substrate 10 corresponding to the first lower waveguide layer, the first active layer, and the first upper waveguide layer, which are partially etched in operation S220-2. The growth process may include: the growth temperature is 680° C., the growth pressure is 100 mbar, and the thickness of the second lower waveguide layer 15 and the second upper waveguide layer 17 are both 90 nm. The structure of the second active layer 16 may be a plurality of multi-quantum well active layer structures, which may include 5 compressive strain well layers and 6 tensile strain barrier layers, each well layer has a thickness of 5 nm, and each barrier layer has a thickness of 9 nm.

[0079] For example, Figure 6 The front cross-sectional view of the structure after the second lower waveguide layer, the second active layer and the second upper waveguide layer are grown on the substrate according to an embodiment of the present invention is schematically shown. Figure 6 shown.

[0080] According to an embodiment of the present invention, the bandgap wavelength of the second lower waveguide layer 15 is 1200 nm, the bandgap wavelength of the second active layer 16 is 1500 nm, and the bandgap wavelength of the second upper waveguide layer 17 is 1200 nm.

[0081] In operation S240, a portion of the second lower waveguide layer 15, the second active layer 16 and the second upper waveguide layer 17 is etched away to expose the substrate 10, so that the remaining portion of the second lower waveguide layer 15, the second active layer 16 and the second upper waveguide layer 17 that is not etched away is the first modulator region 1 and the second modulator region 5.

[0082] According to an embodiment of the present invention, operation S240 may include:

[0083] Operation S240-1: Etch and remove the SiO2 mask layer of the first gain region 3 and the second gain region 7, and then generate a SiO2 mask layer 18 on the first upper waveguide layer of the first gain region 3 and the second gain region 7 and the second upper waveguide layer of other functional regions (first modulator region 1, first front grating region 2, first phase region 4, rear grating region 9, second phase region 8, second front grating region 6 and second modulator region 5), using a 1 μm thick photoresist mask and a buffered oxide etching solution (BOE) to etch out a 20 μm wide SiO2 strip structure 18.

[0084] For example, Figure 7 A top view of a structure after a mask pattern is prepared according to another embodiment of the present invention is schematically shown.

[0085] like Figure 7 As shown, the mask pattern 18 is a stripe structure, and the mask pattern 18 is a SiO2 mask pattern of the first modulator region 1 and the second modulator region 5 , the first gain region 3 and the second gain region 7 .

[0086] Operation S240-2: Reactive ion etching (RIE) is used to etch away a portion of the second lower waveguide layer 15, the second active layer 16, and the second upper waveguide layer 17 to expose the substrate 10, so that the remaining portion of the second lower waveguide layer 15, the second active layer 16, and the second upper waveguide layer 17 that are not etched away are the first modulator region 1 and the second modulator region 5. For example, Figure 8 A front cross-sectional view of a structure after etching is completed according to another embodiment of the present invention is schematically shown.

[0087] like Figure 8As shown, the second lower waveguide layer 15, the second active layer 16 and the second upper waveguide layer 17 from which a portion of the area is etched may be the material from which the first front grating region 2, the first phase region 4, the rear grating region 9, the second phase region 8 and the second front grating region 6 are etched, and the remaining portion of the second lower waveguide layer 15, the second active layer 16 and the second upper waveguide layer 17 from which a portion of the area is not etched may be used to prepare the first modulator region 1 and the second modulator region 5.

[0088] According to an embodiment of the present invention, by using freezing point H2SiO4 and H2O2 solutions to etch the remaining materials on the substrate of the first front grating area 2, the first phase area 4, the rear grating area 9, the second phase area 8 and the second front grating area 6, and cleaning the substrate with deionized water, a front cross-sectional view of the structure obtained in this step is obtained, as shown in FIG. Figure 8 shown.

[0089] In operation S250, a passive layer is formed on the substrate corresponding to the second lower waveguide layer, the second active layer, and the second upper waveguide layer in which partial areas are etched by a butt growth method, wherein the passive layer is flush with the first upper waveguide layer and the second upper waveguide layer, and the passive layer is divided into a first front grating region, a first phase region, a rear grating region, a second phase region, and a second front grating region.

[0090] According to an embodiment of the present invention, MOCVD is used to butt-grow the passive layer 19 of the first front grating region 2, the first phase region 4, the rear grating region 9, the second phase region 8 and the second front grating region 6. The specific growth process can be: the growth temperature is 630°C, the growth pressure is 100mbar, and the band gap wavelength is smaller than the laser emission wavelength. In this embodiment, the band gap wavelength can be 1400nm. For example, Fig. 9 The front cross-sectional view of the structure after the passive layer is grown according to an embodiment of the present invention is schematically shown.

[0091] According to an embodiment of the present disclosure, the material of the passive layer may be InGaAsP or InGaAlAs bulk material.

[0092] In operation S260, a grating structure is prepared in a partial region of the passive layer, wherein the grating structure is a sampled grating.

[0093] According to an embodiment of the present disclosure, a partial region of the passive layer may include the passive layer of the first front grating region 2, the rear grating region 9 and the second front grating region 6. A grating structure 20 is prepared on the passive layer of the first front grating region 2, the rear grating region 9 and the second front grating region 6, and the grating structure may include a sampled grating.

[0094] According to an embodiment of the present disclosure, when preparing a sampled grating, the sampling period length of the sampled gratings in the first front grating area and the second front grating area is smaller than the sampling period length of the sampled grating in the rear grating area; the number of sampling periods of the sampled gratings in the first front grating area and the second front grating area is smaller than the sampling period number of the sampled grating in the rear grating area.

[0095] According to an embodiment of the present disclosure, the above-mentioned preparation method further includes sequentially growing a cladding layer and an electric contact layer on the first upper waveguide layer, the second upper waveguide layer and the passive layer.

[0096] According to an embodiment of the present disclosure, a P-type Zn-doped InP cladding layer 21 and an InGaAs electrical contact layer 22 are sequentially grown on the first upper waveguide layer 13, the second upper waveguide layer 17 and the passive layer 19 by MOCVD, the growth temperature is 630°C, and the growth pressure is 100 mbar. The thickness of the cladding layer can be 1500 nm, and the thickness of the electrical contact layer can be 200 nm. For example, Fig.10 The front cross-sectional view schematically shows a structure after preparing a grating structure, a cladding layer and an electrical contact layer according to an embodiment of the present invention.

[0097] According to the embodiment of the present disclosure, on the cladding layer 21 and the electrical contact layer 22 of each functional region, a 3 μm wide photoresist strip mask is photoetched using a 1 μm thick photoresist, and an etching solution of Br2:HBr:H2O=1:25:80 is used for etching time of 40 seconds; and an etching solution of HCl:H2O=9:1 is used for etching time of 3 minutes to produce an inverted shallow ridge waveguide structure. For example, Fig.11 The side cross-sectional view of the inverted shallow ridge waveguide structure manufactured according to an embodiment of the present invention is schematically shown. Fig.11 As shown, the side cross-section of the inverted shallow ridge waveguide structure made of the cladding layer 21 and the electric contact layer 22 can be an inverted trapezoid.

[0098] According to an embodiment of the present disclosure, the above-mentioned preparation method also includes: etching an electrical isolation groove on the electrical contact layer so that the electrical contact layers of the first modulator region, the first front grating region, the first gain region, the first phase region, the rear grating region, the second phase region, the second gain region, the second front grating region and the second modulator region are spaced apart.

[0099] According to an embodiment of the present invention, an isolation groove pattern 26 is photolithographically formed on the electrical contact layer 22 using a 3 μm rear photoresist, and an etching solution H2SiO4:H2O2:H2O=3:1:1 is used for etching for 10 seconds to form an electrical isolation groove 26 between each functional area, and at the same time, helium ions 23 are implanted into the cladding 21 through the electrical isolation groove. The implantation of helium ions can achieve electrical isolation between each functional area of ​​the first modulator area 1, the first front grating area 2, the first gain area 3, the first phase area 4, the rear grating area 9, the second phase area 8, the second gain area 7, the second front grating area 6 and the second modulator area 5. For example, Fig.12 Schematically shows a front cross-sectional view of a structure after etching an electrical isolation trench and implanting helium ions according to an embodiment of the present invention. Fig.12 shown.

[0100] According to an embodiment of the present invention, the width of the electrical isolation trench may be 50 μm, the injection energy of the helium ions 23 may be 200 KeV, and the injection dose may be 10 14 cm -2 .

[0101] According to an embodiment of the present invention, the above-mentioned preparation method further includes: preparing a p-side electrode 24 on the electrical contact layer of the first modulator region 1, the first front grating region 2, the first gain region 3, the first phase region 4, the back grating region 9, the second phase region 8, the second gain region 7, the second front grating region 6 and the second modulator region 5; thinning the substrate 10, and preparing an n-side electrode 25 on the lower surface of the substrate 10, thereby completing the preparation of the tunable electro-absorption modulated laser. For example, Figure 1 Shown is the fabricated tunable electro-absorption modulated laser.

[0102] According to an embodiment of the present invention, a tunable electro-absorption modulated laser is integrated by sharing a rear grating region and adopting a sampled grating, so that the tunable electro-absorption modulated laser can achieve the effect of doubling the speed and wavelength tuning range of the laser by means of the vernier effect of the sampling gratings before and after the laser, and realize double-end dual-modulation laser emission by sharing the rear grating region, while also reducing the power consumption of the rear grating region, thereby providing a new solution for optical communication systems.

[0103] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present invention.

[0104] Moreover, the shapes and sizes of the components in the figures do not reflect the actual size and proportion, but only illustrate the contents of the embodiments of the present invention. Furthermore, the word "comprising" does not exclude the existence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the existence of a plurality of such elements.

[0105] Similarly, it should be understood that in order to streamline the present invention and aid in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this method of invention should not be interpreted as reflecting the following intention: that the claimed invention requires more features than the features explicitly recited in each claim. More specifically, as reflected in the claims below, the inventive aspects lie in less than all the features of the individual embodiments of the preceding invention. Therefore, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present invention.

[0106] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A tunable electro-absorption modulated laser, comprising: The first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region are located on the same substrate, have the same height and are sequentially attached, wherein: The first gain region and the second gain region each include a first lower waveguide layer, a first active layer and a first upper waveguide layer in a preset order, wherein the first lower waveguide layer is formed on a substrate; The first modulator region and the second modulator region each include a second lower waveguide layer, a second active layer, and a second upper waveguide layer in the preset order, wherein the second lower waveguide layer is formed on the substrate; The first front grating region, the second front grating region, the rear grating region, the first phase region and the second phase region all include a passive layer, and the passive layer is formed on the substrate. The first front grating region, the second front grating region and the rear grating region form a grating structure on the passive layer, and the grating structure includes a sampling grating, wherein double-end double-modulation laser emission is achieved by sharing the rear grating region.

2. The tunable electro-absorption modulated laser according to claim 1, wherein: The first active layer and the second active layer are both multi-quantum well active layers, and the structure of the multi-quantum well active layer includes a plurality of alternately stacked barrier layers and well layers, each of the barrier layers has a thickness of 9 nm, each of the well layers has a thickness of 5 nm, and the multi-quantum well material is InGaAsP or InGaAlAs.

3. The tunable electro-absorption modulated laser according to claim 1, wherein: The first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region all include a cladding layer and an electrical contact layer and a p-side electrode separated by an electrical isolation groove.

4. The tunable electro-absorption modulated laser according to claim 3, wherein: The electrical contact layer and the p-side electrode are sequentially arranged on the cladding layer; The claddings of the first gain region and the second gain region are formed on the first upper waveguide layer; the claddings of the first modulator region and the second modulator region are formed on the second upper waveguide layer; the claddings of the first front grating region, the second front grating region, the first phase region, the second phase region and the back grating region are formed on the passive layer; The lower surface of the substrate is arranged on an n-side electrode.

5. The tunable electro-absorption modulated laser according to claim 3, wherein: The cladding layer and the electrical contact layer are inverted shallow ridge waveguide structures, and the side section of the inverted shallow ridge waveguide structure is in an inverted trapezoidal shape.

6. The tunable electro-absorption modulated laser according to claim 3, wherein: Helium ions are implanted into the electrical isolation trench of the electrical contact layer and the p-side electrode.

7. The tunable electro-absorption modulated laser according to claim 1, wherein: The sampling period lengths of the sampled gratings of the first front grating region and the second front grating region are shorter than the sampling period length of the sampled gratings of the rear grating region; The sampling period number of the sampled gratings of the first front grating area and the second front grating area is smaller than the sampling period number of the sampled gratings of the rear grating area.

8. A method for preparing a tunable electro-absorption modulated laser according to any one of claims 1 to 7, comprising: sequentially growing a first lower waveguide layer, a first active layer and a first upper waveguide layer on a substrate; Etching away a portion of the first lower waveguide layer, the first active layer, and the first upper waveguide layer to expose the substrate, so that the remaining portion of the first lower waveguide layer, the first active layer, and the first upper waveguide layer that are not etched away are the first gain region and the second gain region; sequentially growing a second lower waveguide layer, a second active layer and a second upper waveguide layer on the substrate corresponding to the first lower waveguide layer, the first active layer and the first upper waveguide layer in which a part of the area is etched; Etching away a portion of the second lower waveguide layer, the second active layer, and the second upper waveguide layer to expose the substrate, so that the remaining portion of the second lower waveguide layer, the second active layer, and the second upper waveguide layer that are not etched away are the first modulator region and the second modulator region; Forming a passive layer on the substrate corresponding to the second lower waveguide layer, the second active layer and the second upper waveguide layer whose partial regions are etched by a butt-jointed growth method, wherein the passive layer is flush with the first upper waveguide layer and the second upper waveguide layer, and the passive layer is divided into a first front grating region, a first phase region, a rear grating region, a second phase region and a second front grating region; A grating structure is prepared in a partial area of ​​the passive layer, wherein the grating structure is a sampled grating.

9. The preparation method according to claim 8, further comprising: sequentially growing a cladding layer and an electrical contact layer on the first upper waveguide layer, the second upper waveguide layer and the passive layer; Etching an electrical isolation groove on the electrical contact layer so that the electrical contact layers of the first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region are arranged at intervals; Preparing a p-side electrode on the electrical contact layer of the first modulator region, the first front grating region, the first gain region, the first phase region, the back grating region, the second phase region, the second gain region, the second front grating region and the second modulator region; The substrate is thinned, and an n-side electrode is prepared on the lower surface of the substrate.

10. The method according to claim 8, wherein: The material of the passive layer is InGaAsP or InGaAlAs bulk material.

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