CN108121034B

CN108121034B - Optical component integrating SOA and AWG and preparation method thereof

Info

Publication number: CN108121034B
Application number: CN201711399451.7A
Authority: CN
Inventors: 岳阳阳; 徐红春; 刘成刚; 宋小平
Original assignee: Wuhan Telecommunication Devices Co Ltd
Current assignee: Wuhan Telecommunication Devices Co Ltd
Priority date: 2017-12-22
Filing date: 2017-12-22
Publication date: 2020-07-28
Anticipated expiration: 2037-12-22
Also published as: CN108121034A

Abstract

The invention relates to an optical component and a preparation method thereof, which are used for realizing high integration of SOA and AWG, belong to the technical field of optical communication, and particularly relate to an optical component integrating SOA and AWG and a preparation method thereof. The invention can completely align the active layer of the SOA and the chip layer of the AWG by improving and controlling the production process of the SOA and the AWG, and can reduce the volume of the whole assembly and realize constant output of optical power by controlling the gain of the SOA by adding the isolation layer. In addition, a temperature sensing element, a lens and other elements are integrated on the basis of the basic components again, so that spectral matching with higher precision is realized.

Description

Optical component integrating SOA and AWG and preparation method thereof

Technical Field

The invention relates to an optical component and a preparation method thereof, which are used for realizing high integration of SOA and AWG, belong to the technical field of optical communication, and particularly relate to an optical component integrating SOA and AWG and a preparation method thereof.

Background

With the continuous progress of the optical communication industry, the speed and cost of optical devices severely restrict the development speed of optical communication, and how to effectively increase the transmission rate and transmission capacity of an optical fiber transmission network becomes an important issue of optical fiber communication. Limited by the development of optical chips, the development of optical communication is mainly realized by improving the system capacity at present, and the Wavelength Division Multiplexing (WDM) technology is the best choice for expanding the communication capacity. Array Waveguide Grating (AWG) is a wavelength division multiplexing device commonly used at present, and is widely used due to its advantages of small signal distortion, low error rate, compact structure, easy integration, high channel wavelength adjustment accuracy, low price, strong practicability, and the like.

Semiconductor Optical Amplifiers (SOA for short) are a way to realize long-distance Optical signal transmission, and have the advantages of large working wavelength range, small volume, low power consumption, fast reaction speed, large nonlinearity, capability of being mixed or monolithically integrated with other active and passive optoelectronic devices, mature manufacturing process and the like, so that the Semiconductor Optical Amplifiers play an increasingly important role in WDM system networks and are important devices for realizing all-Optical signal processing and compensating Optical loss in future all-Optical networks.

In long-distance transmission (especially 80km), the loss of the optical fiber reaches more than 20dBm, and the SOA is adopted to amplify the signal so as to counteract the influence caused by the loss of the optical fiber. Generally, when the SOA is used, the SOA is limited by the size of the SOA and is placed inside the module, and now with the miniaturization of the module, the trend of low power consumption is more and more obvious, in order to make full use of the internal space of the module, the SOA is necessarily placed out of the module, and the integrated idea of the SOA and the AWG is generated based on the situation.

At present, the SOA and the AWG are placed in two ways: separate placement and flip-chip integration. When the SOA and the AWG are separately placed as separate elements, the SOA and the AWG are limited by the size of the SOA, the SOA can only be placed in the module, and only the position of the AWG is reserved in the device, so that the whole module is crowded in structure, the power consumption of the module is increased, the SOA is influenced by temperature, and the gain stability of the SOA is poor. Furthermore, fiber connections are considered when using SOA and AWG. The method has the advantages that the ready SOA and AWG elements can be used without considering the corresponding relation between the SOA and the AWG; the disadvantages are insufficient space utilization rate, large volume occupied by elements and large power consumption. The disadvantage of this approach is fatal for low power consumption, miniaturized devices. SOA and AWG flip-chip integration, compare the former, the integrated level is high, and the volume can reduce to some extent, has reduced the device cost, but the passive coupling mode that adopts, to the position requirement height, and the technology operation is more complicated moreover, and luminous power can decline to some extent.

The invention integrates from the growth layers of SOA and AWG, integrates the AWG chip and the SOA chip on the same substrate, and aligns the active layer of SOA and the active region of AWG by controlling the thickness of the material layers of SOA and AWG.

Disclosure of Invention

The invention provides an optical component integrating SOA and AWG and a preparation method thereof. The high integration of SOA and AWG is utilized, and the thicknesses of SOA and AWG structure layers are strictly controlled from the raw material growth layer, so that the coupling efficiency of optical power is improved, and the power loss is reduced.

The invention solves the problems by the following scheme:

a method for preparing an integrated SOA and AWG optical component comprises the following steps:

dividing a silicon substrate into an amplification region and a multiplexing region, and arranging an isolation region between the amplification region and the multiplexing region;

growing an isolation layer for preventing the SOA and the AWG materials from permeating in the isolation region;

depositing in the amplification region to obtain an SOA epitaxial wafer;

depositing an AWG lower cladding layer and a chip layer in the multiplexing region;

etching the waveguide layer, the active region and the chip layer of the AWG of the SOA epitaxial wafer;

depositing an AWG upper cladding layer.

Preferably, the above method for manufacturing an integrated SOA and AWG optical component further includes: preparing a P-surface electrode and an N-surface electrode of the SOA, preparing antireflection films at an optical signal input end and an optical signal output end of the SOA chip, and cleaving.

Preferably, in the above method for manufacturing an integrated SOA and AWG optical component, the isolation layer sequentially includes, from the substrate to the top: a lower layer, a fiber core layer and an upper layer; wherein the refractive index of the upper layer and the lower layer is smaller than that of the core layer.

Preferably, in the above method for manufacturing an integrated SOA and AWG optical component, a mask is formed on the chip layer, and the chip layer, the upper waveguide layer and the active region are etched simultaneously by using an inductively coupled plasma etching method.

Preferably, in the above method for manufacturing an integrated SOA and AWG optical component, the SOA epitaxial wafer sequentially includes, from the substrate to the top:

a substrate layer, the composition comprising InPut;

a buffer layer, the composition of which comprises N-InP;

the lower waveguide layer comprises N-InGaAsP;

an active layer having a composition comprising InGaAsP;

an upper waveguide layer, the composition of which comprises P-InGaAsP;

a buffer layer, the composition comprising: P-InP;

and a contact layer, the composition of which comprises InGaAs.

An integrated SOA and AWG optical component comprising:

a substrate having an amplification region, a multiplexing region, and an isolation region between the amplification region and the multiplexing region;

SOA and AWG, grow on amplification area and multiplexing zone of the said plaque separately;

wherein, the isolation layer includes from the base plate upwards in proper order: a lower layer, a fiber core layer and an upper layer; wherein the refractive index of the upper layer and the lower layer is smaller than that of the core layer.

Preferably, the above optical component integrating SOA and AWG includes: a lens is integrated at the AWG front end.

Preferably, in the optical assembly integrating the SOA and the AWG, the areas of the chip layer, the core layer of the isolation layer and the active region are sequentially increased or decreased or unchanged.

Preferably, in the above optical group integrating an SOA and an AWG, the SOA includes, in order from the substrate upward:

a substrate layer, the composition comprising InPut;

a buffer layer, the composition of which comprises N-InP;

the lower waveguide layer comprises N-InGaAsP;

an active layer having a composition comprising InGaAsP;

an upper waveguide layer, the composition of which comprises P-InGaAsP;

a buffer layer, the composition comprising: P-InP;

and a contact layer, the composition of which comprises InGaAs.

Therefore, the invention has the following advantages:

1. volume: the SOA and the AWG are integrated from the material growth layer, so that two elements can be integrated into one element, the thickness of each layer is controlled according to the volume of a device or a module to be applied, and the space volume of the device or the module is saved.

2. Power consumption: the mode of integrating the SOA and the AWG is started from the material growth layer, so that unnecessary structures in the SOA and the AWG can be completely eliminated, and the power consumption of the SOA and the AWG is reduced;

3. optical power: the mode of integrating the SOA and the AWG is started from the material growth layer, the core layer of the AWG and the active layer of the SOA can be completely corresponding, so that the laser can emit light completely through the SOA, and the mode has no optical power loss or small loss and is only related to the performance of the SOA and the AWG element.

4. Stability: the SOA and the AWG can be simultaneously controlled by adding the TEC controller below the component in a mode of integrating the SOA and the AWG from the material growth layer, no additional element is needed to be added, and the gain error can be stabilized to +/-1 dB.

Drawings

Figure 1 is a front view of an integrated SOA and AWG structure.

Figure 2 is a top view of an SOA and AWG integrated structure.

Figure 3 is a schematic diagram of the structure of an AWG.

Fig. 4 is a schematic diagram of the structure of an SOA.

Fig. 5 is a schematic view of the structure of the spacer layer.

Fig. 6, 7, 8 are schematic views of the positions of the AWG core layer and the SOA active layer.

In the figure, 1, a substrate, 2, a lens, 3, PD, 4, AWG, 5, an isolating device, 6, SOA, 7, an InPut waveguide, 8, an output waveguide, 9, a silicon substrate, 10, a lower cladding, 11, a core layer, 12, an upper cladding, 13 InGaAs contact layers, 14, a P-InP buffer layer, 15, a P-InGaAsP upper waveguide layer, 16, an InGaAsP active layer, 17, an N-InGaAsP lower waveguide layer, 18, an N-InP buffer layer, 19, an InPut substrate, 20, 21, a core layer, and 22 lower layers.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings.

Example 1

As shown in fig. 1 and 2, the substrate 1 is divided into three regions: AWG multiplexing region, isolation region, SOA amplifying region. In the AWG multiplexing region, the basic structure is a multichannel wavelength division multiplexing structure AWG, and the number of signal channels can be adjusted according to requirements, and can be 4, 8 or other; followed by an isolation region whose main function is 1) to prevent reflection of light and to achieve optical path transmission; 2) the situation of mutual permeation is prevented when the structural layers of the SOA and the AWG grow; in the SOA amplifying area, the main structure is a semiconductor optical amplifier SOA, the function is to provide gain and realize the amplification of AWG channel wavelength power, and the basic structure is a semiconductor PN junction. Anti-reflection coatings are applied across the SOA to reduce fresnel reflections at the interface of the semiconductor material and air. In addition, the lens 2 and the PD 3 can be integrated in the AWG multiplexing region.

In order to realize the integration of the SOA and AWG material production layers, the structure and the manufacturing mode of the SOA and AWG need to be analyzed, as shown in fig. 3 and fig. 4, for the AWG, the structure mainly includes four parts: silicon layer 9, lower cladding layer 10, core layer 11, and upper cladding layer 12. The specific manufacturing method comprises the following steps:

TABLE 1 preparation of AWG

The main structure of the SOA includes: an InGaAs contact layer, 14.P-InP buffer layer, 15.P-InGaAsP upper waveguide layer, 16.InGaAsP active layer, 17.N-InGaAsP lower waveguide layer, 18.N-InP buffer layer, 19.InPut substrate. The specific manufacturing method comprises the following steps:

1. the SOA partial structure layer was obtained using a molecular beam epitaxy deposition technique as shown in table 2.

Table 2 preparation method of SOA partial structure layer

2. And carrying out electron beam exposure or ultraviolet lithography on the epitaxial wafer, etching the upper waveguide layer 15 and the active region 16 by adopting a process of combining inductive coupling plasma etching and wet acid etching, wherein the etching depth reaches the SOA lower waveguide layer 17, and preparing the parabolic curved waveguide structure.

3. And growing the P-InP buffer layer 14 and the InGaAs contact layer 13 by using the molecular beam epitaxy equipment growth chamber again, and preparing a P-surface electrode and an N-surface electrode.

And 4, preparing an antireflection film for the input and output ends of the optical signals of the SOA chip, and cleaving.

The isolation region is an indispensable part of the present invention, which not only can transmit the optical path, but also can prevent the mutual penetration when the SOA and AWG are subjected to material growth. The partial structure is composed of reference optical fibers and is mainly divided into three parts: an upper layer 20, a core layer 21, and a lower layer 22. As shown in fig. 5, where the refractive index of the upper layer 20 and the lower layer 22 is smaller than that of the core layer 21, when the optical fiber is incident on the connection surface of the cladding layer and the core layer, the full emission occurs, and the transmission of the optical path in the core layer 21 is realized.

After the process of the SOA and the AWG is completely understood, the SOA and the AWG are integrally prepared by considering a material growth layer, and the steps are as follows:

1. taking a clean silicon chip as a silicon substrate 9 of the AWG and simultaneously as an integrated component substrate 1;

2. dividing the substrate into three parts according to the sizes of SOA and AWG chips, and respectively growing a lower layer 22, a fiber core layer 21 and an upper layer 20 in an isolation region according to the manufacturing process of the optical fiber;

3. obtaining an SOA partial structure by utilizing a molecular beam epitaxy deposition technology;

4. obtaining an AWG lower cladding layer 10 and a core layer 11 by using a plasma enhanced chemical vapor deposition method, wherein the refractive index of the core layer 11 is required to be larger than that of the lower cladding layer 10;

5. by electron beam exposure or ultraviolet lithography, a mask is made on the chip layer 11, and the core layer 11, the upper waveguide layer 15 and the active region 16 are etched on the SOA and the AWG simultaneously by adopting an inductively coupled plasma high-density etching method;

6. depositing the AWG upper cladding layer 12 by using a plasma enhanced chemical vapor deposition method;

7. and preparing a P-surface electrode and an N-surface electrode of the SOA, preparing an antireflection film on the optical signal input end and the optical signal output end of the SOA chip, and cleaving.

The structure may be encapsulated if necessary.

Table 3 design reference for height dimension of structural layer of each element

Fig. 6, 7 and 8 are the most critical parts in the invention: the core layer 11 in the AWG chip corresponds to the active layer 16 in the SOA chip. When the position of the core layer 11 in the AWG chip is higher or lower than the position of the active layer 16 in the SOA chip, as shown in fig. 6, the optical signal transmitted through the AWG cannot enter the SOA after passing through the isolation region, and the coupling efficiency at this time is substantially zero; when the position of the core layer 11 in the AWG chip partially overlaps the position of the active layer 16 in the SOA chip, as shown in fig. 8, after passing through the isolation region, a part of the optical signal transmitted through the AWG enters the SOA, and the coupling efficiency at this time is continuously improved along with the increase of the overlapping area, particularly when the position of the core layer 11 in the AWG chip completely overlaps the position of the active layer 16 in the SOA chip, the optical signal transmitted through the AWG enters the SOA completely after passing through the isolation region, and the coupling efficiency at this time is the largest.

In addition, in the integrated component, if the AWG is considered as a wave combining element, the areas of the core layer 11, the fiber core layer 21, and the active layer 16 may be sequentially increased, so as to ensure that the optical signal can completely enter the SOA; if the AWG is considered as a wavelength division element, the areas of the core layer 11, the fiber core layer 21, and the active layer 16 may be sequentially reduced, so as to ensure that the optical signal can completely enter the SOA; considering that the AWG wavelength multiplexing/demultiplexing function is provided, the sizes of the areas of the core layer 11, the core layer 21, and the active layer 16 must be the same.

Example 2

The present embodiment provides an integrated SOA optical component, including:

and the substrate is used for placing the SOA and the AWG, and can be a single layer structure or an extension of a silicon layer in the AWG structure.

And the group of wavelength division multiplexers AWG with N signal channels realizes the combination or the division of different wavelengths.

The semiconductor optical amplifier SOA can realize constant output of optical power by adjusting gain of the SOA. The SOA can be used as an input port to realize power amplification, and can also be used as an output port to realize optical power amplification.

A set of isolation devices. An isolation layer can be added between the integrated SOA and the AWG to realize the signal transmission of the optical path and organize the mutual permeation of materials.

In addition, the thickness of the growth layers of the SOA and the AWG is strictly controlled in the aspect of production process, the chip region of the AWG is completely aligned with the active region of the SOA, the coupling efficiency is improved, and the optical power loss is reduced.

The technical solution adopted in this embodiment may include, but need not necessarily include, an extended function unit:

1. and the lens group is used for shaping, expanding, paralleling or converging the light beams. The type may be a ball lens or a non-ball lens, and the material may be silicon, glass, or others.

2. And the temperature sensor is combined with the semiconductor cooler to regulate and control the ambient temperature of the AWG, reduce the channel loss of the AWG and improve the stability of the SOA. The temperature sensing element may be a thermistor or other type of temperature sensor, and the function performed is the same.

3. And the detector is used for monitoring the laser current or the optical power.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Although the drawings are used more frequently, 1. substrate, 2. lens, 3.PD, 4.AWG, 5. isolation device, 6.SOA, 7. InPut waveguide, 8. output waveguide, 9. silicon substrate, 10. lower cladding, 11. chip layer, 12. upper cladding, 13.InGaAs contact layer, 14.P-InP buffer layer, 15.P-InGaAsP upper waveguide layer, 16.InGaAsP active layer, 17.N-InGaAsP lower waveguide layer, 18.N-InP buffer layer, 19.InPut substrate, 20 upper layer, 21 core layer, 22 lower layer. Etc., but does not exclude the possibility of using other terms. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.

Claims

1. A method for preparing an integrated SOA and AWG optical component is characterized by comprising the following steps:

growing an isolation layer for preventing the AWG and the SOA material from permeating in the isolation region;

depositing in the amplification region to obtain an SOA partial structure;

depositing a AWG lower cladding layer (10) and a chip layer (11) in the multiplexing region;

etching the SOA epitaxial wafer waveguide layer (15), the active layer (16) and the AWG chip layer (11);

depositing an AWG upper cladding layer (12);

wherein the isolation layer comprises, in order from the silicon substrate upward: a lower cladding layer, a core layer (21), and an upper cladding layer; wherein the refractive index of the upper cladding layer and the lower cladding layer is less than that of the core layer;

wherein the content of the first and second substances,

when the AWG is a wave combination element, the areas of the chip layer (11), the fiber core layer (21) and the active layer (16) are increased in sequence; when the AWG is a wave splitting element, the areas of the chip layer (11), the fiber core layer (21) and the active layer (16) are reduced in sequence; when the AWG has the function of combining and splitting waves, the areas of the chip layer (11), the core layer (21) and the active layer (16) are the same.

2. The method of making an integrated SOA and AWG optical component of claim 1, further comprising: preparing a P-surface electrode and an N-surface electrode of the SOA, preparing antireflection films at an optical signal input end and an optical signal output end of the SOA chip, and cleaving.

3. A method of manufacturing an integrated SOA and AWG optical component as claimed in claim 1, wherein the chip layer (11) is masked and the chip layer (11), the upper waveguide layer (15) and the active layer (16) are etched simultaneously by means of inductively coupled plasma etching.

4. The method of claim 1 wherein the SOA epitaxial wafer comprises, in order from the silicon substrate up:

a substrate layer, the composition comprising InPut;

a buffer layer, the composition of which comprises N-InP;

the lower waveguide layer comprises N-InGaAsP;

an active layer of composition including InGaAsP

An upper waveguide layer, the composition of which comprises P-InGaAsP;

a buffer layer, the composition comprising: P-InP;

and a contact layer, the composition of which comprises InGaAs.

5. An integrated SOA and AWG optical assembly, comprising:

a silicon substrate having an amplification region, a multiplexing region, and an isolation region between the amplification region and the multiplexing region; an isolation layer for preventing the AWG and the SOA materials from permeating grows in the isolation region;

SOA and AWG, grow on amplification area and multiplexing area of the said silicon base plate separately;

wherein the isolation layer comprises, in order from the silicon substrate upward: a lower layer, a fiber core layer and an upper layer; wherein the refractive index of the upper layer and the lower layer is less than that of the core layer;

wherein, a chip layer is arranged in the AWG, and an active layer/active layer is arranged in the SOA;

wherein the content of the first and second substances,

6. An integrated SOA and AWG optical component as claimed in claim 5, comprising: a lens (2) is integrated at the AWG front end.

7. An integrated SOA and AWG optical component as claimed in claim 5 wherein said SOA comprises, in order from said silicon substrate up:

a substrate layer, the composition comprising InPut;

a buffer layer, the composition of which comprises N-InP;

the lower waveguide layer comprises N-InGaAsP;

an active layer having a composition comprising InGaAsP;

an upper waveguide layer, the composition of which comprises P-InGaAsP;

a buffer layer, the composition comprising: P-InP;

and a contact layer, the composition of which comprises InGaAs.