CN217469102U

CN217469102U - On-chip integrated multi-wavelength laser applied to SWDM optical module

Info

Publication number: CN217469102U
Application number: CN202222213444.6U
Authority: CN
Inventors: 王坤; 鄢静舟; 季晓明; 薛婷; 杨奕; 吴建忠
Original assignee: Fujian Huixin Laser Technology Co ltd
Current assignee: Fujian Huixin Laser Technology Co ltd
Priority date: 2022-08-23
Filing date: 2022-08-23
Publication date: 2022-09-20
Anticipated expiration: 2032-08-23

Abstract

The utility model discloses an on-chip integrated multi-wavelength laser applied to an SWDM optical module, which relates to the technical field of semiconductor photoelectron, and comprises a substrate, a first VCSEL unit, a second VCSEL unit, a third VCSEL unit and a fourth VCSEL unit, wherein the first VCSEL unit, the second VCSEL unit, the third VCSEL unit and the fourth VCSEL unit are stacked on the surface of the substrate from top to bottom; the center wavelength of the first VCSEL unit is 940nm, and the center wavelength of the second VCSEL unit is 910 nm; the third VCSEL unit has a center wavelength of 880nm and the fourth VCSEL unit has a center wavelength of 850 nm. The utility model discloses pile up integrated design with the VCSEL unit of 4 different center wavelengths in same VCSEL chip, compare in the VCSEL chip that adopts 4 independent settings among the prior art, on-chip integrated form VCSEL chip has that occupation space is little, the encapsulation is with low costs, production efficiency is high, product yield is high and product reliability height advantage, can satisfy the design demand of following SWDM optical module better.

Description

On-chip integrated multi-wavelength laser applied to SWDM optical module

Technical Field

The utility model relates to a semiconductor photoelectron technical field, in particular to be applied to on chip integrated form multi-wavelength laser of SWDM optical module.

Background

With the rapid development of communication technology and the increasing abundance of application types, the traffic of the data center shows a situation of increasing by multiples year by year, the requirement of the data center on bandwidth is higher and higher, and the construction of the next generation data center needs a transmission scheme with lower cost and wider bandwidth.

The physical carrier for internal communication of the data center is an SWDM (short wave wavelength division multiplexing) optical module which comprises four optical transmitters with different wavelengths, four optical receivers with signal detectors, a wavelength division multiplexer, a demultiplexer and a multimode fiber duplex optical connector. The four optical transmitters with different wavelengths are four independent VCSEL chips, namely 850nm VCSELs, 880nm VCSELs, 910nm VCSELs and 940nm VCSELs. The four VCSEL chips are independently manufactured and integrated together through packaging (surface mounting and routing). However, the method of realizing integration by packaging has the disadvantages of large occupied space, high packaging cost, great yield loss in the packaging process, and influence on the overall reliability due to the introduction of too many potential defects of surface mounting and wire bonding.

Disclosure of Invention

The utility model provides a be applied to on-chip integrated form multi-wavelength laser of SWDM optical module, the problem that its main aim at exists solves prior art.

The utility model adopts the following technical scheme:

an on-chip integrated multi-wavelength laser applied to an SWDM optical module comprises a substrate, and a first VCSEL unit, a second VCSEL unit, a third VCSEL unit and a fourth VCSEL unit which are stacked on the surface of the substrate from bottom to top; the center wavelength of the first VCSEL unit is 940nm, and the center wavelength of the second VCSEL unit is 910 nm; the third VCSEL unit has a center wavelength of 880nm and the fourth VCSEL unit has a center wavelength of 850 nm.

Further, the first VCSEL unit includes, from bottom to top, a first bottom N-type DBR, a 940nm active region, a first buried tunnel junction, and a first top N-type DBR; the second VCSEL unit comprises a second bottom N-type DBR, a 910nm active region, a second buried tunnel junction and a second top N-type DBR from bottom to top; the third VCSEL unit comprises a third bottom N-type DBR, a 880nm active region, a third buried tunneling junction and a third top N-type DBR from bottom to top; the fourth VCSEL unit includes, from bottom to top, a fourth bottom N-type DBR, a 850nm active region, a fourth buried tunnel junction, and a fourth top N-type DBR.

Furthermore, the first bottom N-type DBR, the first top N-type DBR, the second bottom N-type DBR, the second top N-type DBR, the third bottom N-type DBR, the third top N-type DBR, the fourth bottom N-type DBR, and the fourth top N-type DBR are periodic structures alternately composed of a high refractive index film and a low refractive index film, and the period number is gradually reduced from bottom to top.

Furthermore, the diameters of the first buried tunnel junction and the fourth buried tunnel junction are equal, and the value range is 5-150 μm.

Further, a first N-type metal electrode is arranged at the bottom of the substrate, and a second N-type metal electrode is arranged at the top of the fourth VCSEL unit.

Furthermore, a first common electrode is arranged on the top of the first VCSEL unit, a second common electrode is arranged on the top of the second VCSEL unit, and a third common electrode is arranged on the top of the third VCSEL unit; the first common electrode, the second common electrode and the third common electrode each include a positive electrode of the lower VCSEL unit and a negative electrode of the upper VCSEL unit.

Further, the substrate is a GaAs substrate.

Compared with the prior art, the utility model discloses the beneficial effect who produces lies in:

1. the utility model discloses pile up the integrated design with the VCSEL unit of 4 different wavelengths in same VCSEL chip, compare in the VCSEL chip that adopts 4 independent settings among the prior art, on-chip integrated form VCSEL chip has that occupation space is little, the encapsulation is with low costs, production efficiency is high, product yield is high and product reliability height advantage, can satisfy the design demand of SWDM optical module.

2. The utility model discloses well each VCSEL unit adopts the epitaxial structure of the structure of N type DBR-active area-buried tunnel junction-N type DBR, can realize following mesh from this: firstly, current limitation is realized by burying a tunneling junction, so that the problems of low production yield, poor product consistency and the like in the prior art by adopting an oxidation limitation method are solved; secondly, the polarity of the top N-type DBR in each VCSEL unit is reversed by utilizing the buried tunneling junction, so that the top N-type DBR can replace a P-type DBR, the optical loss and the series resistance are greatly reduced, the conversion efficiency is improved, and the high-speed operation is realized; and thirdly, after the top N-type DBR is used for replacing the top P-type DBR, the epitaxial non-uniformity caused by the fact that the top P-type DBR needs high C doping can be overcome, and the epitaxial uniformity and the yield are effectively improved.

Drawings

Fig. 1 is a schematic structural diagram of the on-chip integrated multi-wavelength laser of the present invention.

In the figure:

10. a substrate;

11. a first VCSEL unit;

111. a first bottom N-type DBR;

112. a 940nm active region;

113. a first buried tunnel junction;

114. a first top N-type DBR;

12. a second VCSEL unit;

121. a second bottom N-type DBR;

122. a 910nm active region;

123. a second buried tunnel junction;

124. a second top N-type DBR;

13. a third VCSEL unit;

131. a third bottom N-type DBR;

132. 880nm active region;

133. a third buried tunnel junction;

134. a third top N-type DBR;

14. a fourth VCSEL unit;

141. a fourth bottom N-type DBR;

142. an 850nm active region;

143. a fourth buried tunnel junction;

144. a fourth top N-type DBR;

15. a first N-type metal electrode;

16. a second N-type metal electrode;

17. a first common electrode;

18. a second common electrode;

19. a third common electrode.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings. Numerous details are set forth in the following description in order to provide a thorough understanding of the present invention, but it will be apparent to one skilled in the art that the present invention may be practiced without these details.

As shown in fig. 1, the present invention provides an on-chip integrated multi-wavelength laser applied to an SWDM optical module, which includes a substrate 10, and a first VCSEL unit 11, a second VCSEL unit 12, a third VCSEL unit 13, and a fourth VCSEL unit 14 stacked on the surface of the substrate from bottom to top; the center wavelength of the first VCSEL unit 11 is 940nm, and the center wavelength of the second VCSEL unit 12 is 910 nm; the third VCSEL unit 13 has a central wavelength of 880nm and the fourth VCSEL unit 14 has a central wavelength of 850 nm. The main inventive concept of the present invention is to stack and integrate 4 VCSEL units with different central wavelengths into the same VCSEL chip, so that the VCSEL chip can emit 4 laser beams required by the SWDM optical module, and since the band gap corresponding to the long wavelength material is smaller than the band gap corresponding to the short wavelength material, the short wavelength laser can be partially absorbed by the long wavelength material, based on this, the present invention provides a design principle: the central wavelength of the VCSEL units located in the next layer must be longer than the central wavelength of the VCSEL units located in the previous layer to avoid the absorption of the short wavelength laser light by the long wavelength material along the lasing direction.

As shown in fig. 1, the first VCSEL11 cell includes, from bottom to top, a first bottom N-type DBR111, a 940nm active region 112, a first buried tunnel junction 113, and a first top N-type DBR 114; the second VCSEL unit 12 comprises, from below and above, a second bottom N-type DBR121, a 910nm active region 122, a second buried tunneling junction 123, and a second top N-type DBR 124; the third VCSEL unit 13 includes, from below and above, a third bottom N-type DBR131, a 880nm active region 132, a third buried tunnel junction 133, and a third top N-type DBR 134; the fourth VCSEL unit 14 includes, from below and above, a fourth bottom N-type DBR141, an 850nm active region 142, a fourth buried tunnel junction 143, and a fourth top N-type DBR 144.

As shown in fig. 1, the function of the buried tunnel junction of the present invention includes: firstly, current limitation is realized by burying a tunnel junction, so that the problems of low production yield, poor product consistency and the like in the prior art by adopting an oxidation limitation method are solved; secondly, the polarity of the top N-type DBR in each VCSEL unit is reversed by utilizing the buried tunneling junctions, so that the top P-type DBR can be replaced, the optical loss and the series resistance are greatly reduced, the conversion efficiency is improved, and the high-speed operation is realized; thirdly, after the top N-type DBR is used for replacing the top P-type DBR, the epitaxial non-uniformity caused by the fact that the top P-type DBR needs high C doping can be overcome, and the epitaxial uniformity and the yield are effectively improved.

As shown in fig. 1, the first buried tunnel junction 113 to the fourth buried tunnel junction 143 have the same structure, and include a P-type heavily doped layer and an N-type heavily doped layer from bottom to top. Wherein, the material of the P-type heavily doped layer includes but is not limited to InGaAsP, InGaAlAs, AlInAs, GaAs, AlGaAs, GaAsSb, the material of the N-type heavily doped layer includes but is not limited to AlGaAs, GaAs, GaInAs, InP; doping atoms of the P-type heavily doped layer comprise C, Mg, Zn or Be, and doping atoms of the N-type heavily doped layer comprise Se or Te; p-type heavily doped layer and N-type heavily doped layerLayer doping concentration of 10 ¹⁹ -10 ²⁰ cm ^-3 An order of magnitude; the thickness range of the P-type heavily doped layer is 8-50 nm, and the thickness range of the N-type heavily doped layer is 8-50 nm. The diameters of the first buried tunnel junction 113 to the fourth buried tunnel junction 143 are all equal, and the value range is 5-150 μm.

As shown in fig. 1, the first bottom N-type DBR111, the first top N-type DBR114, the second bottom N-type DBR121, the second top N-type DBR124, the third bottom N-type DBR131, the third top N-type DBR134, the fourth bottom N-type DBR141, and the fourth top N-type DBR144 are periodic structures formed by alternately high-refractive-index films and low-refractive-index films, and the period number is gradually reduced from bottom to top, thereby ensuring that the laser emits light upward.

As shown in fig. 1, the bottom of the substrate 10 is provided with a first N-type metal electrode 15, and the top 14 of the fourth VCSEL unit is provided with a second N-type metal electrode 16, so that 4 VCSEL unit cells can be simultaneously lit. For realizing the individual modulation, the first VCSEL unit top 11 is provided with a first common electrode 17, the second VCSEL unit 12 is provided with a second common electrode 18, and the third VCSEL unit 13 is provided with a third common electrode 19; the first common electrode 17, the second common electrode 18 and the third common electrode 19 each include a positive electrode of the lower VCSEL unit and a negative electrode of the upper VCSEL unit

As shown in fig. 1, the substrate 10 is a GaAs substrate, and based on this, AlGaAs/GaAs, AlAs/GaAs, InGaAlAs/InP, InGaAsP/InP, and AlGaInAs/AlInAs semiconductor materials can be used for the bottom N-type DBR and the top N-type DBR of each VCSEL unit, the active layer of each VCSEL unit can be designed as a plurality of multiple quantum well layers (MQW) arranged in an overlapping manner, and the MQWs layers are stacked and arranged by GaAs, AlGaAs, GaAsP, and InGaAs materials.

As shown in fig. 1, the main inventive concept of the present invention is to stack and integrate 4 VCSEL units with different wavelengths into one VCSEL chip, and compare to the prior art that adopts 4 independently arranged VCSEL chips, the present invention has the advantages that:

(1) the VCSEL units with 4 different wavelengths are stacked and integrated in the same VCSEL chip, so that the occupied space can be effectively reduced, the chip packaging area is greatly saved, and the miniaturization design requirement of the SWDM optical module can be conveniently met.

(2) The on-chip integrated VCSEL chip saves the total chip manufacturing process cost, the testing cost and the packaging cost, and also saves a coupler required by horizontal arrangement of 4 independent VCSEL chips in the conventional SWDM optical module. In addition, the failure rate of the on-chip integrated VCSEL chip is low, so that the maintenance and replacement cost can be saved.

(3) The on-chip integrated VCSEL chip can complete the manufacture of various chips through one-time flow sheet, and the VCSEL chips with different wavelengths are not required to be produced by multiple chip processes, so that the total chip manufacturing process and time can be greatly reduced, and the production efficiency is improved in multiples.

(4) Generally, the production yield of a single VCSEL chip is only 90% or more, and the cumulative production yield of 4 VCSEL chips is lower. Therefore, the on-chip integrated VCSEL chip can greatly reduce the total production reject ratio and improve the overall yield of products.

(5) The failure rate of the on-chip integrated VCSEL chip is lower than that of a multi-chip packaging level by a plurality of orders of magnitude, potential defects and early failures caused by packaging patch and wire bonding can be greatly reduced, and the simplified design principle of reliability design is met.

To sum up, the utility model has the advantages of occupation space is little, the encapsulation is with low costs, production efficiency is high, the product yield is high and the product reliability is high, can satisfy the design demand of SWDM optical module.

The above is only a specific embodiment of the present invention, but the design concept of the present invention is not limited thereto. All utilize the utility model discloses a design concept is right the utility model discloses carry out insubstantial change, all should belong to the infringement the utility model discloses the action of protection scope.

Claims

1. An on-chip integrated multi-wavelength laser applied to an SWDM optical module is characterized in that: the device comprises a substrate, and a first VCSEL unit, a second VCSEL unit, a third VCSEL unit and a fourth VCSEL unit which are stacked on the surface of the substrate from bottom to top; the center wavelength of the first VCSEL unit is 940nm, and the center wavelength of the second VCSEL unit is 910 nm; the third VCSEL unit has a center wavelength of 880nm and the fourth VCSEL unit has a center wavelength of 850 nm.

2. An on-chip integrated multi-wavelength laser applied to an SWDM optical module as claimed in claim 1, wherein: the first VCSEL unit comprises a first bottom N-type DBR, a 940nm active region, a first buried tunnel junction and a first top N-type DBR from bottom to top; the second VCSEL unit comprises a second bottom N-type DBR, a 910nm active region, a second buried tunnel junction and a second top N-type DBR from bottom to top; the third VCSEL unit comprises a third bottom N-type DBR, a 880nm active region, a third buried tunneling junction and a third top N-type DBR from bottom to top; the fourth VCSEL unit includes, from bottom to top, a fourth bottom N-type DBR, a 850nm active region, a fourth buried tunnel junction, and a fourth top N-type DBR.

3. An on-chip integrated multi-wavelength laser applied to an SWDM optical module as claimed in claim 2, wherein: the first bottom N-type DBR, the first top N-type DBR, the second bottom N-type DBR, the second top N-type DBR, the third bottom N-type DBR, the third top N-type DBR, the fourth bottom N-type DBR and the fourth top N-type DBR are all periodic structures formed by alternately arranging high-refractive-index thin films and low-refractive-index thin films, and the periodicity is gradually reduced from bottom to top.

4. An on-chip integrated multi-wavelength laser applied to an SWDM optical module as claimed in claim 2, wherein: the diameters of the first buried tunnel junction and the fourth buried tunnel junction are equal, and the value range is 5-150 mu m.

5. An on-chip integrated multi-wavelength laser applied to an SWDM optical module, as defined in claim 1, wherein: and a first N-type metal electrode is arranged at the bottom of the substrate, and a second N-type metal electrode is arranged at the top of the fourth VCSEL unit.

6. An on-chip integrated multi-wavelength laser applied to an SWDM optical module as claimed in claim 5, wherein: the top of the first VCSEL unit is provided with a first common electrode, the top of the second VCSEL unit is provided with a second common electrode, and the top of the third VCSEL unit is provided with a third common electrode; the first common electrode, the second common electrode and the third common electrode each include a positive electrode of the lower VCSEL unit and a negative electrode of the upper VCSEL unit.

7. An on-chip integrated multi-wavelength laser applied to an SWDM optical module as claimed in claim 1, wherein: the substrate is a GaAs substrate.