WO2018196689A1

WO2018196689A1 - Multi-wavelength hybrid integrated light emitting array

Info

Publication number: WO2018196689A1
Application number: PCT/CN2018/083892
Authority: WO
Inventors: 祝宁华; 黄庆超; 陈伟; 刘建国
Original assignee: 中国科学院半导体研究所
Priority date: 2017-04-27
Filing date: 2018-04-20
Publication date: 2018-11-01
Also published as: CN107026391A

Abstract

Disclosed is a multi-wavelength hybrid integrated light emitting array, comprising a plurality of light processing units, wherein each of the light processing units comprises: an active optical device (1), including a first substrate (11), with the material of the first substrate being an III-V group semiconductor material and same being used for emitting laser, and a beam splitting optical waveguide (2), including a second substrate (21), with the material of the second substrate being the same as that of the first substrate, and being used for splitting the laser to form beam split laser. The substrates of the active optical device and the beam splitting optical waveguide are the same III-V group semiconductor material, so that optical loss caused by coupling of different materials is reduced, the power consumption of the light emitting array is favorably reduced, and moreover, the preparation process and the size of the multi-wavelength hybrid integrated light emitting array are improved.

Description

Multi-wavelength hybrid integrated light emitting array

Technical field

The present invention relates to the field of semiconductor integration technologies, and in particular, to a multi-wavelength hybrid integrated light emitting array.

Background technique

Compared with discrete functional optical devices, photonic integration greatly reduces the size and power consumption of optical modules, and is a key technology that must be relied upon to realize high-capacity, low-power optical networks in the future. The high-speed multi-wavelength hybrid integrated light-emitting array is the core component of the high-speed optical transmission network. A common multi-wavelength laser emitting array is constructed such that an InP (indium phosphide)-based DFB (Distributed Feedback Laser) produces a multi-wavelength laser that is split into a lithium niobate via a Y-type optical waveguide on a silicon substrate. The optical waveguide is modulated and then intensity modulated by combining the silicon-based Y-waveguides. Silicon-based optical waveguides are ideal materials for optical waveguides due to their low loss and their refractive index can be adjusted by doping. However, since the active optoelectronic devices are mostly III-V semiconductor materials, the integration between the optical devices of different materials has a certain optical loss, and the preparation process is complicated. In addition, the size of the silicon-based Y-type optical waveguide is large, which is a challenge for photonic integration technology.

Summary of the invention

It is an object of the present invention to provide a multi-wavelength hybrid integrated light emitting array comprising a plurality of light processing units, each of the light processing units comprising:

An active optical device for emitting laser light, comprising a first substrate, the first substrate being a III-V semiconductor material;

A split beam optical waveguide for splitting the laser beam into a split beam laser, comprising a second substrate, the material of the second substrate being the same as the first substrate.

Optionally, the III-V semiconductor material comprises indium phosphide.

Optionally, each of the light processing units further includes:

a pair of parallel optical waveguides connected to the split optical waveguide for changing a phase of the split laser;

Three traveling wave electrodes for providing a modulation voltage for the parallel optical waveguide;

A combined optical waveguide is coupled to the parallel optical waveguide for combining the phase-modulated beam splitting lasers to form a combined laser.

Optionally, it also includes:

An arrayed waveguide grating is used to combine a plurality of combined beam lasers emitted by a plurality of light processing units into a multi-wavelength laser.

Optionally, the substrate material of the combined optical waveguide is the same as the material of the first substrate.

Optionally, the active optical device further includes:

a first buffer layer on the first substrate;

An active layer on the first buffer layer;

a grating layer on the active layer;

A first upper waveguide layer is located on the grating layer.

Optionally, the grating layer on one side of the beam splitting optical waveguide is coated with an anti-reflection film, and the other side of the grating layer is plated with a high reflective film.

Optionally, the split optical waveguide further includes:

a second buffer layer on the second substrate;

a core layer on the second buffer layer;

A second upper waveguide layer is located on the core layer.

Alternatively, the width of the optical waveguide composed of the first buffer layer, the active layer, and the first upper waveguide layer becomes smaller as the forbidden band width of the core layer becomes larger.

Optionally, the parallel optical waveguide material is lithium niobate.

The active optical devices are mostly III-V semiconductor materials, so the split-beam optical waveguide using the III-V semiconductor material as the base can greatly simplify the preparation process of the light-emitting array and improve the yield;

Since the same III-V semiconductor material is used between the active optical device and the passive splitting optical waveguide, the optical loss due to the coupling of different materials can be greatly reduced, which is beneficial to the reduction of the power consumption of the optical transmitting array;

Although the silicon-based splitting optical waveguide has less loss due to materials, the size of the silicon-based splitting waveguide is large, and the size of the multi-wavelength laser emitting array can be greatly reduced after using the InP-based splitting optical waveguide;

The combined optical waveguide also uses a III-V semiconductor material, which can be well integrated with the latter InP-based AWG (array waveguide grating), and the loss, preparation process and size of the optical integrated emission array are improved;

In the modulator, the phase-modulated parallel optical waveguide is made of lithium niobate, and the modulation bandwidth of the light-emitting array can reach several tens of gigahertz.

DRAWINGS

1 is a schematic structural diagram of a multi-wavelength hybrid integrated light emitting array according to an embodiment of the present invention;

2 is a schematic diagram of an active optical device and a split optical waveguide according to an embodiment of the present invention.

detailed description

In the prior art, the multi-wavelength laser emitting array is mainly composed of an InP (indium phosphide)-based DFB laser, a silicon-based Y-beam splitting optical waveguide, a modulator, and a silicon-based Y-type combined optical waveguide. Although the loss of the silicon-based optical waveguide is small, and its refractive index can be adjusted by doping, it is an ideal material for the optical waveguide. However, since the active optoelectronic devices are mostly III-V semiconductor materials, the integration between the optical devices of different materials has a certain optical loss, and the preparation process is complicated. In addition, the size of the silicon-based Y-type optical waveguide is large, which is a challenge for photonic integration technology. Based on the foregoing technical problems, the present invention provides a multi-wavelength hybrid integrated light emitting array in which both the active optical device and the passive splitting optical waveguide use the same III-V semiconductor material as the substrate. In addition, the present invention also employs a plurality of active optical devices that can emit lasers of different wavelengths to form a hybrid integration of multi-wavelength lasers. Since the high-reflection film is a reflection film having a high reflectance, in general, the reflectance of the high-reflection film is 90% or more, and most of the incident light or almost all of the incident light can be reflected back. Therefore, the present invention is to make the grating structure. Other light energy outside of the selected mode is reflected back to convert to lasing mode energy, thereby enhancing the emitted laser energy, increasing the efficiency of the multi-wavelength hybrid integrated light emitting array.

The present invention will be further described in detail below with reference to the specific embodiments of the invention,

1 is a schematic structural diagram of a multi-wavelength hybrid integrated light emitting array according to an embodiment of the present invention. As shown in FIG. 1 , an embodiment of the present invention provides a multi-wavelength hybrid integrated light emitting array, including multiple optical processing units, each of which The optical processing unit includes an active optical device 1, a split optical waveguide 2, a parallel optical waveguide 3, a traveling wave electrode 4, a combined optical waveguide 5, and an AWG 6. Wherein, the active optical device 1 emits laser light; the split optical waveguide 2 receives the laser light emitted by the active optical device 1 and splits the same, obtains a split laser and transmits the split laser to the parallel optical waveguide 3; After receiving the beam splitting laser, the waveguide 3 changes its phase in combination with the modulation voltage supplied from the traveling wave electrode 4. The combined optical waveguide 5 receives the split laser and combines it to form a combined laser. Finally, the multi-beam combined laser emitted by the plurality of cells is emitted to the AWG (array beam grating) 6, and the AWG6 combines the multi-beam combined laser to obtain a multi-wavelength laser, and the multi-beam laser is passed through an optical fiber. transmission.

The active optical device 1, such as a DFB (Distributed Feedback Laser) active region, includes a first substrate, and the first substrate material is a III-V semiconductor. The material of the first substrate is the same as the material of the second substrate of the splitting optical waveguide 2, and the active optical device 1 and the split optical waveguide 2 (the Y-beam splitting optical waveguide which can select the deep-ridge optical waveguide structure) pass The active-passive-end coupling method is coupled. Because the substrate materials are the same, the optical loss caused by the coupling of different materials can be greatly reduced, which is beneficial to the reduction of power consumption of the light-emitting array. At the same time, the III-V semiconductor material is used. The splitting optical waveguide 2 as a substrate can greatly simplify the preparation process of the light emitting array and improve the yield. Since indium phosphide is the most common and is the most widely used in the art, the III-V semiconductor in the embodiment of the present invention selects indium phosphide, and in other embodiments, it can also be GaAs (gallium arsenide) or GaN. Other III-V compounds such as (GaN).

According to an embodiment of the present invention, the combined optical waveguide 5 also selects an InP-based Y-type optical waveguide having a deep ridge type optical waveguide structure identical to the split optical waveguide, and the deep ridge type optical waveguide structure has polarization independent and small bending The advantage of radius helps to reduce size and increase integration.

Further, the material of the parallel optical waveguide can be lithium niobate, which has a good electrooptic effect, a short response time, and a wide transparent wavelength range, and is an ideal modulation material. Since the splitting optical waveguide splits a laser beam into two laser beams, the present invention provides a pair of parallel optical waveguides, three traveling wave electrodes placed in parallel with the parallel optical waveguides, and two parallel optical waves for each two traveling wave electrodes. The waveguide provides a modulation voltage, and different modulation voltages are applied to the parallel optical waveguide, which can change the refractive index of the lithium niobate, so that the phase of the original phase-convergent beam splitting laser also changes accordingly. After the phase-changed beam splitting laser passes through the combined optical waveguide, a combined laser is formed, and the intensity of the combined laser is also changed accordingly. For example, if the phases of the two beam splitting lasers are 180° out of phase, the intensity of the combined laser is 0; if the phase of the two beam splitting lasers does not change, the intensity of the combined laser does not change. This achieves modulation of the combined laser intensity.

Further, since the AWG 6 is an InP-based AWG, in order to better integrate with the AWG 6 and reduce optical loss due to material difference, the combined optical waveguide 5 in the present embodiment is also an InP substrate.

2 is a schematic diagram of an active optical device and a split optical waveguide according to an embodiment of the present invention. As shown in FIG. 2, the active optical device 1 includes:

A first substrate 11, in the embodiment of the present invention, the material of the first substrate 11 is InP (may be other III-V semiconductors).

A first buffer layer 12 is disposed on the first substrate 11. In the embodiment of the present invention, an InP semiconductor material is also selected.

An active layer 13 on the first buffer layer 12, using a strained InGaAsP multiple quantum well of a lattice matching material, wherein different active layer 13 materials are used, and the wavelength of the laser emitted by the active optical device is also different In order to achieve the purpose of multi-wavelength laser hybrid integration.

A grating layer 14 is disposed on the active layer 13, wherein the grating layer 14 can be fabricated by holographic interference exposure, two-beam interferometry or nanoimprinting. In addition, since there is a laser oscillation in the active optical device, the grating layer on the side of the beam splitting optical waveguide (ie, the grating layer along the optical path direction) is coated with an anti-reflection film in the grating layer. The other side is coated with a high-reflection film with a reflectivity of 90% or more, which can reflect most of the incident light or almost all of the incident light, while reflecting other light energy outside the selected mode of the grating structure. The energy is injected to enhance the emitted laser energy.

A first upper waveguide layer 15 is located on the grating layer 14 and is a lattice matched InP waveguide layer.

According to an embodiment of the invention, the beam splitting optical waveguide 2 comprises:

a second substrate 21, the material of the second substrate 21 should be identical to the first substrate 11, and thus InP is used. In other embodiments, the active optical device 1 and the split optical waveguide 2 can share the same substrate. ;

A second buffer layer 22 is disposed on the second substrate 21, and the second buffer layer 22 may also be selected from the same material as the first buffer layer 12, or the split optical waveguide 2 may be shared with the active optical device 1. The same buffer layer, that is, the first buffer layer 12 and the second buffer layer 22 are the same buffer layer.

A core layer 23 is disposed on the second buffer layer 22, and the core layer 23 is an InGaAsP core layer; the second upper waveguide layer 24 is an undoped or semi-insulating InP to reduce material absorption loss.

a second upper waveguide layer 24 is disposed on the core layer 23. The first buffer layer 12, the active layer 13, and the first upper waveguide layer 15 constitute an optical waveguide, and the width of the optical waveguide conforms to the InGaAsP core layer. The forbidden band width is different, and the smaller the forbidden band width of the selected core layer is, the width of the optical waveguide is larger when the polarization is independent, and the lithography process tolerance is large.

In summary, the multi-wavelength hybrid integrated light-emitting array provided by the invention can greatly simplify the preparation process of the light-emitting array, improve the yield, reduce the power consumption of the light-emitting array, and the modulation bandwidth can reach several tens of gigahertz, and can be greatly reduced. The size of the multi-wavelength laser emitting array has greatly improved its preparation process and size.

The specific embodiments of the present invention have been described in detail, and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A multi-wavelength hybrid integrated light emitting array, comprising: a plurality of light processing units, each light processing unit comprising:

An active optical device for emitting laser light, comprising a first substrate, the first substrate being a III-V semiconductor material;

A split beam optical waveguide for splitting the laser beam into a split beam laser, comprising a second substrate, the material of the second substrate being the same as the first substrate.
The multi-wavelength hybrid integrated light emitting array of claim 1 wherein said III-V semiconductor material comprises indium phosphide.
The multi-wavelength hybrid integrated light emitting array of claim 1 , wherein each of the light processing units further comprises:

a pair of parallel optical waveguides connected to the split optical waveguide for changing a phase of the split laser;

Three traveling wave electrodes for providing a modulation voltage for the parallel optical waveguide;

A combined optical waveguide is coupled to the parallel optical waveguide for combining the phase-modulated beam splitting lasers to form a combined laser.
The multi-wavelength hybrid integrated light emitting array of claim 3, further comprising:

An arrayed waveguide grating is used to combine a plurality of combined beam lasers emitted by a plurality of light processing units into a multi-wavelength laser.
The multi-wavelength hybrid integrated light emitting array according to claim 3, wherein the substrate material of the combined optical waveguide is the same as the material of the first substrate.
The multi-wavelength hybrid integrated light emitting array of claim 1 , wherein the active optical device further comprises:

a first buffer layer on the first substrate;

An active layer on the first buffer layer;

a grating layer on the active layer;

A first upper waveguide layer is located on the grating layer.
The multi-wavelength hybrid integrated light emitting array according to claim 6, wherein the grating layer on one side of the beam splitting optical waveguide is plated with an anti-reflection film, and the other side of the grating layer is plated with a high reflective film.
The multi-wavelength hybrid integrated light emitting array according to claim 1 or 7, wherein the beam splitting optical waveguide further comprises:

a second buffer layer on the second substrate;

a core layer on the second buffer layer;

A second upper waveguide layer is located on the core layer.
The multi-wavelength hybrid integrated light emitting array according to claim 8, wherein a width of the optical waveguide composed of the first buffer layer, the active layer, and the first upper waveguide layer is along with the core layer The forbidden band width becomes larger and smaller.
The multi-wavelength hybrid integrated light emitting array of claim 3 wherein said parallel optical waveguide material is lithium niobate.