Electroabsorption modulated laser, optical transmitting assembly and optical terminal

Abstract

This application discloses an electro-absorption modulated laser. The electro-absorption modulated laser includes a laser region, an electrically isolated region, and an electro-absorption modulator region. The electrically isolated region is disposed between the laser region and the electro-absorption modulator region. The laser region is used to generate laser light. The laser light is coupled into the electro-absorption modulator region connected to the laser region. The electro-absorption modulator region is used to modulate the laser light to obtain signal light. A waveguide layer is included below the first active layer of the electro-absorption modulator region. In this application, the electro-absorption modulator region can couple a portion of the laser light into the waveguide layer, thereby increasing the saturation absorption power of the electro-absorption modulator and increasing the output power of the electro-absorption modulated laser.

Description

Technical Field

[0001] This application relates to the field of optical communication, and in particular to electroabsorption modulated lasers, optical emitting components and optical terminals. Background Technology

[0002] In an optical communication system, the optical transmitting terminal generates signal light through a modulator. The signal light is transmitted through optical fiber to the optical receiving terminal. The optical receiving terminal demodulates the signal light using a demodulator to obtain an electrical signal.

[0003] An electro-absorption modulated laser (EAB) is a monolithically integrated externally modulated light source. An EAB consists of a laser region and an electro-absorption modulator region. The laser light generated in the laser region is coupled into the EAB, which is connected to the laser region. When an electro-modulation signal is applied to the EAB, it modulates the laser light to obtain the signal light. The output power of the laser region is the laser power, and the output power of the EAB or the EAB region is the signal light power. To a certain extent, the laser power and the signal light power are proportional. Therefore, the signal light power can be increased by increasing the laser power. However, as the laser power increases, the active layer of the EAB will saturate, thus limiting the output light power of the EAB. Summary of the Invention

[0004] This application provides an electro-absorption modulated laser, an optical emitting component, and an optical terminal. By adding a waveguide layer to the material structure of the modulator region, the technical solution disclosed in this application can increase the power of the laser when the electro-absorption modulator region enters saturation, thereby increasing the output power of the electro-absorption modulated laser.

[0005] This application provides an electrically absorbed modulated laser. The electrically absorbed modulated laser includes a laser region, an electrically isolated region, and an electrically absorbed modulator region located on the same semiconductor substrate. The electrically isolated region is disposed between the laser region and the electrically absorbed modulator region, serving to electrically isolate the laser region and the electrically absorbed modulator region. The laser region is used to generate laser light. The laser light is coupled into the electrically absorbed modulator region connected to the laser region. The electrically absorbed modulator region is used to modulate the laser light to obtain signal light. The electrically absorbed modulator region includes a first active layer and a waveguide layer. The waveguide layer is disposed between the substrate and the first active layer.

[0006] In this application, the optical confinement factor of the first active layer in the electro-absorption modulator region is reduced due to the introduction of a waveguide layer. At this time, a portion of the laser emitted from the laser region is coupled into the waveguide layer, increasing the saturated absorption power of the electro-absorption modulator region. Therefore, this application can improve the output power of the electro-absorption modulated laser.

[0007] In one alternative embodiment of the first aspect, the refractive index of the waveguide layer is less than the effective refractive index of the first active layer. In this embodiment, the waveguide layer absorbs a portion of the introduced laser light, thereby reducing the power of the signal light and causing loss. This application specifies that the refractive index of the waveguide layer is less than the effective refractive index of the first active layer, thus reducing laser loss within the waveguide layer.

[0008] In one alternative embodiment of the first aspect, the length of the electro-absorption modulator region is greater than 300 micrometers in a first direction. The first direction is the propagation direction of the laser in the laser region. In this application, by increasing the length of the electro-absorption modulator region, the extinction ratio of the signal light can be improved.

[0009] In one alternative embodiment of the first aspect, the electro-absorption modulator region includes a first P electrode and a first N electrode. The first P electrode and the first N electrode have a traveling-wave electrode structure. When the length of the electro-absorption modulator region is relatively long, the parasitic capacitance of the electro-absorption modulator region is large, thereby reducing the modulation bandwidth of the electro-absorption modulator region. When the first P electrode and the first N electrode have a traveling-wave electrode structure, the influence of the electrode's parasitic capacitance on the modulation bandwidth can be reduced. Furthermore, the modulation efficiency is highest when the propagation speed of the electro-modulated signal in the electrode is equal to the propagation speed of the optical signal in the waveguide, and their phases are consistent, and the theoretical modulation bandwidth is infinite.

[0010] In one alternative embodiment of the first aspect, the waveguide layer includes an upper cladding layer and a core layer. The upper cladding layer is disposed between the first active layer and the core layer. When the upper cladding layer has the same structure as the substrate material, the thickness of the core layer can be reduced by increasing the upper cladding layer. Furthermore, the processing cost of the core layer is generally greater than that of an upper cladding layer of the same thickness. This reduces processing costs.

[0011] In one alternative embodiment of the first aspect, the refractive index of the upper cladding is lower than the effective refractive index of the first active layer. In this embodiment, the upper cladding absorbs a portion of the introduced laser light, thereby reducing the power of the signal light and causing loss. This application specifies that the refractive index of the upper cladding is lower than the effective refractive index of the first active layer, thereby reducing laser loss in the upper cladding.

[0012] In one alternative embodiment of the first aspect, the waveguide layer further includes a lower cladding layer. The lower cladding layer is disposed between the substrate and the core layer. By increasing the thickness of the lower cladding layer, the thickness of the core layer can be reduced. Furthermore, the processing cost of the core layer is generally greater than that of a lower cladding layer of the same thickness. Therefore, this application can reduce processing costs.

[0013] In one alternative embodiment of the first aspect, the refractive index of the lower cladding layer is less than the effective refractive index of the first active layer. In this embodiment, the lower cladding layer absorbs a portion of the introduced laser light, thereby reducing the power of the signal light and causing loss. This application specifies that the refractive index of the lower cladding layer is less than the effective refractive index of the first active layer, thus reducing laser loss in the lower cladding layer.

[0014] In one alternative of the first aspect, the thickness of the upper cladding layer is between 0.01 micrometers and 5 micrometers.

[0015] In one alternative of the first aspect, the thickness of the waveguide layer is between 0.03 micrometers and 6 micrometers.

[0016] In one alternative embodiment of the first aspect, the electro-absorption modulator region has a ridge structure. The electro-absorption modulator region includes a first portion and a second portion located below the first portion. The width of the second portion is greater than the width of the first portion. A first active layer belongs to the first portion. The substrate belongs to the second portion. The waveguide layer includes a first waveguide layer and a second waveguide layer. The first waveguide layer belongs to the first portion, and the second waveguide layer belongs to the second portion. Because the waveguide layer can have a relatively thick thickness, a larger process tolerance can be achieved when etching to form the first portion during the fabrication of the electro-absorption modulator region.

[0017] In one alternative embodiment of the first aspect, the second part is a ridge structure, comprising a third part and a fourth part located below the third part. The width of the fourth part is greater than the width of the third part. The second waveguide layer belongs to the third part, and the substrate belongs to the fourth part. This allows for flexible control of the output power of the electroabsorption modulated laser by varying the proportion of signal light in the first active layer and the waveguide layer according to the width of the third part.

[0018] In one alternative approach of the first aspect, in order to better ensure the process tolerance during processing, the difference between the width of the first part and the width of the third part is greater than 4 micrometers.

[0019] In one alternative embodiment of the first aspect, the first active layer includes a first quantum well layer. The laser region includes a second active layer, which in turn includes a second quantum well layer. The projections of the first and second quantum well layers onto a first plane share a common region. The first plane is perpendicular to the upper surface of the substrate. The normal to the first plane is parallel to the propagation direction of the laser in the laser region.

[0020] In one alternative of the first aspect, the waveguide layer is made of indium gallium arsenide phosphide (InGaAsP) or indium gallium aluminum arsenide (InGaAlAs).

[0021] In one alternative embodiment of the first aspect, the waveguide layer extends to the boundary between the electrically isolated region and the laser region. When the waveguide layer extends to the boundary between the electrically isolated region and the laser region, the waveguide layer lies below the lower beam-confining layer in the electrically isolated region. The waveguide layer has the function of increasing the output power of the electrically absorbed modulated laser. Therefore, this application can improve the utilization rate of the electrically isolated region.

[0022] In one alternative embodiment of the first aspect, the length of the laser region is between 400 micrometers and 2000 micrometers. Generally, the longer the laser region, the greater its output power. The output power of the laser region determines the output power of the electroabsorption modulated laser. This application increases the output power of the electroabsorption modulated laser by adding a waveguide layer. Accordingly, this application further increases the output power of the laser region by increasing its length.

[0023] A second aspect of this application provides an optical emitting component. The optical emitting component includes a photodetector and an electro-absorption modulated laser as described in the first aspect or any embodiment thereof. The signal light generated by the electro-absorption modulated laser includes backlight and forward light. The electro-absorption modulated laser is used to output forward light. The photodetector is used to receive the backlight and convert it into an electrical signal.

[0024] A third aspect of this application provides an optical terminal. The optical terminal includes a processor and an optical emitting component. The optical emitting component includes an electro-absorption modulated laser as described in the first aspect or any embodiment of the first aspect. The processor is used to provide an electro-modulation signal to the electro-absorption modulated laser. The electro-absorption modulated laser is used to modulate the laser according to the electro-modulation signal to obtain signal light. Attached Figure Description

[0025] Figure 1 A schematic diagram of the passive optical network system framework for the application scenario of this application;

[0026] Figure 2 This is a schematic diagram of the electroabsorption modulated laser provided in this application;

[0027] Figure 3 This is a side view of the electroabsorption modulated laser provided in this application;

[0028] Figure 4 This is a cross-sectional schematic diagram of the electroabsorption modulator region of the ridge-shaped structure provided in this application;

[0029] Figure 5 A cross-sectional schematic diagram of the electroabsorption modulator region of the double-ridged structure provided in this application;

[0030] Figure 6A cross-sectional schematic diagram of the electroabsorption modulator region, including the ridge structure of the upper cladding, provided in this application;

[0031] Figure 7 A cross-sectional schematic diagram of the electroabsorption modulator region, including the double-ridged structure of the upper cladding, provided in this application;

[0032] Figure 8 This is a schematic diagram of the electrical connections of the electroabsorption modulator region provided in this application;

[0033] Figure 9 This is another electrical connection diagram of the electroabsorption modulator region provided in this application;

[0034] Figure 10 This is a top view of the electroabsorption modulated laser provided in this application;

[0035] Figure 11 This is a schematic diagram of the structure of the optical emitting component provided in this application;

[0036] Figure 12 This is a schematic diagram of the structure of the optical terminal provided in this application. Detailed Implementation

[0037] This application provides an electro-absorption modulated laser, an optical emitting component, and an optical terminal. By introducing a waveguide layer, the technical solution of this application can improve the saturation absorption power of the electro-absorption modulator, thereby increasing the output power of the electro-absorption modulated laser.

[0038] The electro-absorption modulated laser of this application can be applied in the field of optical communication. For example, it can be applied to passive optical network (PON) systems. Figure 1 This is a schematic diagram of the PON system framework for the application scenario of this application. Figure 1 As shown, the PON system includes an optical line terminal (OLT) 101, an optical distribution network (ODN) 102, and optical terminals 103-105. The PON system is a point-to-multipoint single-fiber bidirectional optical access network (in... Figure 1In this PON system, one OLT corresponds to three optical terminals. The ODN 102 uses optical fiber and passive components (e.g., splitter / combiner 1021). In the PON system, the splitter / combiner 1021 is the core point-to-multipoint device, used to separate and collect signal light transmitted through the network. Specifically, in the downlink direction, the OLT 101 distributes the signal light to all optical terminals via the splitter / combiner 1021; in the uplink direction, signal light from each optical terminal is time-divisionally coupled to the same optical fiber via the splitter / combiner 1021 and transmitted to the OLT 101. Optical terminals 103-105 can be Optical Network Units (ONUs) or Optical Network Terminals (ONTs). It should be understood that optical terminals can also be called optical network terminals or PON customer-side equipment, etc. This application does not limit this terminology.

[0039] During signal light transmission, fiber optic cables and the splitter / combiner 1021 incur losses. The magnitude of these losses is generally proportional to the distance between the OLT 101 and the optical terminal, as well as the branching ratio of the splitter / combiner. Therefore, increasing the optical transmission power of the OLT 101 or optical terminal is beneficial for increasing the coverage area of ​​the PON system. The OLT 101 or optical terminal can use an electro-absorption modulated laser to generate the signal light. An electro-absorption modulated laser consists of a laser region and an electro-absorption modulator region. The output power of the laser region is the laser power, and the output power of the electro-absorption modulated laser or electro-absorption modulator region is the signal light power. To a certain extent, the laser power and the signal light power are proportional. Therefore, the signal light power can be increased by increasing the laser power. However, as the laser power increases, the active layer of the electro-absorption modulator region will saturate, thus limiting the output power of the electro-absorption modulated laser.

[0040] Therefore, this application provides an electrically absorbed modulated laser. The electrically absorbed modulated laser includes a laser region, an electrically isolated region, and an electrically absorbed modulator region located on the same semiconductor substrate. The electrically absorbed modulator region includes a waveguide layer and a first active layer. The waveguide layer is disposed between the substrate and the first active layer. In this case, the electrically absorbed modulator region can introduce a portion of the laser light into the waveguide layer, increasing the saturation absorption power of the electrically absorbed modulator. Therefore, this application can improve the output power of the electrically absorbed modulated laser.

[0041] It should be understood that Figure 1 The PON system described here is just one application scenario of the electroabsorption modulated laser in this application. In practical applications, the electroabsorption modulated laser can also be used in other scenarios. For example, fiber optic communication between gateways and wireless access points (APs), fiber optic communication between submarine cables or base stations, etc.

[0042] Figure 2 This is a schematic diagram of the electroabsorption modulated laser provided in this application. Figure 2 As shown, along the positive Z-axis, the electroabsorption modulated laser includes an electroabsorption modulator region, an electroisolation region, and a laser region located on the same semiconductor substrate 202. The boundary between the electroabsorption modulator region and the electroisolation region is located in plane 207, and the boundary between the electroisolation region and the laser region is located in plane 208. Along the positive Y-axis, the electroabsorption modulated laser includes an N-electrode layer 201, a substrate 202, an active layer, a ridge waveguide, and a P-electrode layer.

[0043] The active layer comprises an upper optical confinement layer, a quantum well layer, and a lower optical confinement layer. The upper and lower optical confinement layers provide carriers to the quantum well layer and confine photons in the vertical direction. The thickness of either the upper or lower optical confinement layer is between 0.05 and 0.1 micrometers. To reduce losses, the upper and lower optical confinement layers can be unintentionally doped quaternary materials, such as InGaAlAs with a graded refractive index. The quantum well layer is used to convert electrical energy into photons. The quantum well layer is also an unintentionally doped quaternary material, such as InGaAlAs with a graded refractive index. The quantum well layer can be a multi-quantum-well active region layer. The thickness of the quantum well layer is between 0.1 and 0.2 micrometers.

[0044] The P-electrode layer, also known as the upper electrode layer, is made of materials such as titanium, platinum, or gold alloys. Its thickness ranges from 0.5 to 2 micrometers. The N-electrode layer, also known as the lower electrode layer, is made of materials such as gold-germanium-nickel alloys or gold. Its thickness ranges from 0.2 to 0.5 micrometers. The N-electrode layers in the laser region and the electro-absorption modulator region have a common electrode structure (the same electrode). For traveling-wave electrode modulators, the N-electrode layer can be located on the front side of the electro-absorption modulated laser; please refer to the subsequent description of traveling-wave electrode structures for details.

[0045] The laser region is used to generate laser light. The laser region can be a distributed feedback laser region or a distributed Bragg reflector laser region. Along the positive Y-axis, the laser region includes a second N-electrode layer, a second substrate, a second active layer, a second ridge waveguide, and a second P-electrode layer 210. The second active layer includes a second upper optical confinement layer, a second quantum well layer, and a second lower optical confinement layer. When a forward bias current exceeding its threshold is applied to the laser region, the laser region generates laser light. Specifically, when a sufficiently strong forward bias current is applied to the second P-electrode layer 210, the second quantum well layer acts as a resonant cavity to generate stable laser oscillations. The second quantum well layer generates stimulated emission through laser oscillation, thereby generating laser light. Laser light is output from the left end face (plane 208) of the laser region. After passing through the electrically isolated region, the laser light is introduced into the electrically absorbed modulator region.

[0046] The electro-absorption modulator region is used to modulate the laser to obtain signal light. Along the positive Y-axis, the electro-absorption modulator region includes a first N-electrode layer, a first substrate, a waveguide layer 203, a first active layer, a first ridge waveguide, and a first P-electrode layer 209. The first active layer includes a first upper optical confinement layer 106, a first quantum well layer 205, and a first lower optical confinement layer 204. The waveguide layer is also called a passive waveguide layer. The waveguide layer can be made of indium gallium arsenide phosphide (InGaAsP) or indium gallium aluminum arsenide (InGaAlAs). When the laser is introduced into the electro-absorption modulator region, a portion of the laser light is introduced into the first active layer, and the remaining portion is introduced into the waveguide layer. When an electro-modulation signal is applied to the electro-absorption modulator region, the region modulates the laser light to obtain signal light.

[0047] The waveguide layer absorbs some of the introduced laser light, thereby reducing the signal light power to some extent and causing losses. Specifically, after some laser light is introduced into the waveguide layer, the waveguide layer absorbs some of it, causing a decrease in laser power. This application can limit the refractive index of the waveguide layer to be less than the effective refractive index of the first active layer, thereby reducing the laser power in the waveguide layer. Reducing the laser power in the waveguide layer also reduces losses within the waveguide layer. When the waveguide layer includes an upper cladding and / or a lower cladding, the refractive index of the waveguide layer refers to the effective refractive index.

[0048] An electrically isolated region is located between the laser region and the electro-absorption modulator region. Because the laser region operates under forward bias and the electro-absorption modulator region operates under reverse bias, a high-resistance electrically isolated region is needed to reduce crosstalk. The electrically isolated region can be formed by deep etching or ion implantation. Along the positive Y-axis, the electrically isolated region includes a first N-electrode layer, a first substrate, a waveguide layer, a first active layer, and a first ridge waveguide. By isolating the electrical connection between the laser region and the electro-absorption modulator region, the electrically isolated region isolates crosstalk between the electro-modulation signal and the laser bias current. Specifically, the electrically isolated region isolates the electrical connection between the first P-electrode layer and the second P-electrode layer. Furthermore, when a contact layer is included between the first ridge waveguide and the first P-electrode layer, the electrically isolated region may not include a contact layer.

[0049] In other embodiments, a high-reflectivity film is coated on the right end face of the laser region. The high-reflectivity film is used to increase the reflectivity of the right end face of the laser region, thereby increasing the output power of the laser region. An anti-reflection film can be coated on the left end face of the electro-absorption modulator region. The signal light output from the electro-absorption modulator region is emitted from the left end face. By adding an anti-reflection film, it is beneficial to reduce the reflection loss of the signal light and increase the output power of the electro-absorption modulator region.

[0050] It should be understood that Figure 2The electro-absorption modulated laser shown is merely an example. In practical applications, those skilled in the art can make adaptive modifications to the electro-absorption modulated laser according to their needs.

[0051] For example, such as Figure 2 As shown, the first quantum well layer and the second quantum well layer belong to the same quantum well layer. In practical applications, the first quantum well layer and the second quantum well layer can belong to different quantum well layers. Specifically, when the first quantum well layer and the second quantum well layer belong to different quantum well layers, the first quantum well layer and the second quantum well layer can include one or more of the following distinguishing features: The first quantum well layer and the second quantum well layer have different thicknesses. The first quantum well layer and the second quantum well layer are made of different materials. When the first quantum well layer and the second quantum well layer have the same thickness, the first quantum well layer and the second quantum well layer are misaligned in the Y-axis direction, or in other words, the projection of the first quantum well layer on plane 207 and the projection of the second quantum well layer on plane 207 do not coincide. Similarly, the first upper light-dispersing layer and the second upper light-dispersing layer can belong to different light-dispersing layers. The first lower light-dispersing layer and the second lower light-dispersing layer can belong to different light-dispersing layers.

[0052] For example, such as Figure 2 As shown, the first active layer, waveguide layer, first N-electrode layer, and first ridge waveguide extend to plane 208. In practical applications, the second active layer, waveguide layer, second N-electrode layer, and second ridge waveguide can extend to plane 207. In this case, along the positive Y-axis, the electrically isolated region includes the second N-electrode layer, second substrate, waveguide layer, second active layer, and second ridge waveguide. It should be understood that in practical applications, the second active layer, waveguide layer, second N-electrode layer, and second ridge waveguide can extend to the middle region of the isolation region. In this case, along the positive Y-axis, the electrically isolated region includes the first N-electrode layer, second N-electrode layer, first substrate, second substrate, waveguide layer, first active layer, second active layer, first ridge waveguide, and second ridge waveguide.

[0053] For example, such as Figure 2 As shown, the first N-electrode layer extends to plane 208, and the second N-electrode layer extends to plane 208. The first N-electrode layer and the second N-electrode layer belong to the same N-electrode layer. In practical applications, the electrical isolation region may not include the first N-electrode layer. In this case, the first N-electrode layer extends to plane 207, and the second N-electrode layer extends to plane 208. The second N-electrode layer and the first N-electrode layer are isolated by the isolation region.

[0054] For example, Figure 3 This is a side view of the electroabsorption modulated laser provided in this application. Figure 3As shown, the electroabsorption modulated laser also includes a grating 302, a capping layer 303, and a contact layer 304. The waveguide layer 203 includes a lower cladding layer 301 and a core layer 305. The material of the lower cladding layer 301 can be indium phosphide (InP). The lower cladding layer 301 is divided into a first lower cladding layer and a second lower cladding layer by a plane 208. The electroabsorption modulator region and the electroisolation region include the first lower cladding layer, and the laser region includes the second lower cladding layer. The grating 302 is located in the laser region. The grating 302 is used for mode selection of the laser to achieve single-mode lasing. The material of the capping layer 303 can be InP. The capping layer 303 is located between the upper light confinement layer and the contact layer 304. The thickness of the contact layer 304 is between 0.05 micrometers and 0.3 micrometers. To facilitate ohmic contact with the P-electrode layer, the contact layer 304 is heavily doped In. 0.53 Ga 0.47 As. Doping concentration greater than 1E19cm -3 .

[0055] In this application, the output power of the electroabsorption modulated laser can be increased by adding a waveguide layer. However, this application will reduce the extinction ratio of the signal light to some extent. Specifically, the formula for calculating the extinction ratio (ER) of the signal light is as follows:

[0056] ER=4.343×Γ×[α QW (V off )-α QW (V on )]×L

[0057] Where Γ is the light confinement factor of the second quantum well layer. α QW (V off α represents the absorption coefficient of the electro-absorption modulator region when a low-level signal is applied. QW (V on Let be the absorption coefficient of the electro-absorption modulator region when a high-level signal is applied. Let L be the length of the electro-absorption modulator region. After adding the waveguide layer, the optical confinement factor of the second quantum well layer will decrease. At this time, according to the above formula, the ER of the signal light will decrease. Therefore, this application increases the ER by increasing the length of the electro-absorption modulator region. Specifically, this application can limit the length of the electro-absorption modulator region in the first direction to be greater than 300 micrometers or greater than 700 micrometers. The first direction is the propagation direction of the laser in the laser region. Figure 2 The negative direction of the Z-axis in the diagram.

[0058] In the foregoing Figure 2In the design, the electro-absorption modulator region has a ridge-shaped structure. The electro-absorption modulator region includes a first portion and a second portion located below the first portion. The width of the second portion is greater than the width of the first portion. The second portion includes an active layer, a waveguide layer, and a substrate. To improve process tolerance, the boundary between the second and first portions can be placed in the waveguide layer. Specifically, Figure 4 This is a cross-sectional schematic diagram of the electroabsorption modulator region of the ridge structure provided in this application. Figure 4 for Figure 3 A schematic diagram of the cross-section of plane 207. (See diagram below.) Figure 4 As shown, along the positive Y-axis, the electroabsorption modulator region includes a first N-electrode layer 201, a substrate 202, a waveguide layer 203, a first lower optical confinement layer 204, a first quantum well layer 205, a first upper optical confinement layer 206, an upper cover layer 303, a first contact layer 304, and a first P-electrode layer 209. The waveguide layer 203 includes a lower cladding layer 301 and a core layer 305.

[0059] The electro-absorption modulator region has a ridge structure. It comprises an upper first part and a lower second part. A first N-electrode layer 201 and a substrate 202 belong to the lower second part. A first lower optical confinement layer 204, a first quantum well layer 205, a first upper optical confinement layer 206, a capping layer 303, a first contact layer 304, and a first P-electrode layer 209 belong to the upper first part. The boundary between the first and second parts is a straight line 401. Line 401 divides the waveguide layer 203 into a first waveguide layer and a second waveguide layer. The first waveguide layer belongs to the first part, and the second waveguide layer belongs to the second part. When line 401 is located within the waveguide layer, because the waveguide layer can have a relatively thick thickness, there can be a larger process tolerance during the fabrication of the electro-absorption modulator region. Furthermore, this makes it easier for the electro-absorption modulator region to achieve fundamental transverse mode operation.

[0060] To flexibly control the output power of the signal light, the electroabsorption modulator region can have a double-ridge structure. Specifically, Figure 5 This is a cross-sectional schematic diagram of the electroabsorption modulator region of the double-ridged structure provided in this application. Figure 5 As shown, in Figure 4Based on this, the second part of the electro-absorption modulator region includes a third part and a fourth part located below the third part. The width of the fourth part is greater than the width of the third part. The boundary line between the fourth part and the third part is a straight line 501. The second waveguide layer belongs to the third part. The substrate 202 and the first N-electrode layer 201 belong to the fourth part. The proportion of signal light in the first active layer and waveguide layer is related to the ratio of the width of the second waveguide layer to the width of the first waveguide layer, that is, the power ratio of the first laser and the second laser is related to the width of the second waveguide layer. Therefore, by adjusting the width of the second waveguide layer (i.e., the width of the third part), the ratio of the width of the second waveguide layer to the width of the first waveguide layer can be changed, thereby changing the proportion of signal light in the first active layer and waveguide layer. Furthermore, the proportion of signal light in the first active layer and waveguide layer is related to the output power of the electro-absorption modulator region. Therefore, this application can flexibly control the output power of the electro-absorption modulator region by adjusting the width of the second waveguide layer.

[0061] To reduce the fabrication cost of waveguide layer 203, waveguide layer 203 may include an upper cladding layer, a core layer, and a lower cladding layer. Specifically, Figure 6 This is a cross-sectional schematic diagram of the electroabsorption modulator region, which includes a ridge-shaped structure with an upper cladding, as provided in this application. Figure 6 As shown, in Figure 4 Based on this, the waveguide layer 203 includes an upper cladding layer 601, a core layer 305, and a lower cladding layer 301. The upper cladding layer 601 is disposed between the first lower optical confinement layer 204 and the core layer 305. The processing cost of the core layer 305 is generally greater than that of the upper cladding layer 601 or the lower cladding layer 301 of the same thickness. Therefore, when the waveguide layer 203 includes a lower cladding layer or an upper cladding layer, the processing cost can be reduced by decreasing the thickness of the core layer.

[0062] It should be understood that when the waveguide layer includes the upper cladding, Figure 6 The electroabsorption modulator region in the image has a ridge-shaped structure. In practical applications, the electroabsorption modulator region can also have a double-ridge structure. Specifically, Figure 7 This is a cross-sectional schematic diagram of the electroabsorption modulator region, including the upper cladding, of the double-ridged structure provided in this application. Figure 7 As shown, in Figure 5 Based on this, the waveguide layer 203 includes an upper cladding layer 601, a core layer 305, and a lower cladding layer 301. The upper cladding layer 601 is disposed between the first lower optical confinement layer 204 and the core layer 305.

[0063] At this point, the upper cladding 601, core layer 305, and lower cladding 301 form a waveguide, thereby reducing the thickness of the core layer 305. The thickness of the upper cladding 601 can be from 0.01 micrometers to 5 micrometers. The thickness of the waveguide layer 203 can be from 0.03 micrometers to 6 micrometers. Furthermore, since the waveguide layer absorbs some of the introduced laser light, it reduces the power of the second signal light to a certain extent, resulting in loss. This application can limit the refractive index of the upper cladding 601 and / or the lower cladding 301 to be less than the effective refractive index of the first active layer, reducing laser loss in the waveguide layer.

[0064] When the electroabsorption modulator region has a double-ridge structure, the width of the first part is d1 micrometers, and the width of the third part is d2 micrometers. To better ensure the process tolerance during manufacturing, the difference between d2 and d1 can be limited to be greater than 4.

[0065] Increasing the length of the electro-absorption modulator region increases the parasitic capacitance, thereby reducing the modulation bandwidth. Furthermore, the equivalent circuit of the electro-absorption modulator region is no longer a lumped-parameter circuit, and the electro-modulated signal will reflect at both ends of the region, further reducing the modulation bandwidth. Specifically, Figure 8 This is a schematic diagram of the electrical connections of the electroabsorption modulator region provided in this application. Figure 8 As shown, the electromodulation signal is applied to the middle of the first P-electrode layer 209. Therefore, the electromodulation signal is reflected at both ends of the electroabsorption modulator region, thus affecting the modulation bandwidth of the electroabsorption modulator region. Furthermore, the longer the electroabsorption modulator region, the greater the effect of the reflection.

[0066] Therefore, the P electrode and N electrode in this application are traveling-wave electrode structures. The electroabsorption modulator region with the traveling-wave electrode structure is a traveling-wave electrode modulator. Figure 9 This is another electrical connection diagram of the electroabsorption modulator region provided in this application. (See diagram below.) Figure 9 As shown. An electrical modulation signal is applied to the input terminal of the first P-electrode layer 209. The input terminal is... Figure 2 Plane 207 in the middle. The direction of light transmission is as follows: Figure 9 As indicated by the arrows, the optical transmission direction is the same as the transmission direction of the electrically modulated signal. The output terminal of the first P-electrode layer 209 is connected to a matching load. The matching load is connected to the first N-electrode layer 201. The first N-electrode layer 201 is grounded. At this time, within each small segment of the transmission direction of the electrically modulated signal, the parallel capacitance C of the electro-absorption modulator region is compensated by the series-connected matching load, thereby forming a characteristic impedance. The characteristic impedance can prevent the reflection of the electrically modulated signal from the output terminal of the first P-electrode layer 209, thereby reducing the impact of reflection on the modulation bandwidth.

[0067] exist Figure 2In this configuration, the first N-electrode layer is located on the opposite side of the electro-absorption modulator region. When the electro-absorption modulator region has a ridge or double-ridge structure, if the boundary between the first and second parts is below the waveguide layer, the first N-electrode layer can be located on the front side of the electro-absorption modulator region. For example, the first N-electrode layer is located on... Figure 5 On the boundary line 501 in the middle. Figure 10 This is a top view of the electroabsorption modulated laser provided in this application. Figure 10 As shown, the electroabsorption modulated laser includes an electroabsorption modulator region, an electroisolation region, and a laser region. The electroabsorption modulator region includes a first P-electrode layer 1002, a first N-electrode layer 1001, and a first N-electrode layer 1003. The first N-electrode layers 1001 and 1003 are on the front side of the electroabsorption modulator region. Furthermore, the first P-electrode layer 1002 serves as the signal electrode of the coplanar waveguide, while the first N-electrode layers 1001 and 1003 on either side serve as ground electrodes. A coplanar waveguide is also called a coplanar microstrip transmission line. Coplanar waveguides propagate transverse electromagnetic waves, and their characteristic impedance can be flexibly designed to match the load, reducing electrical signal reflection from the load and increasing the modulation bandwidth.

[0068] In other embodiments, the second N-electrode layer of the laser region is located on the front side of the laser region. For example... Figure 10 As shown, the laser region includes a second P-electrode layer 1005, a second N-electrode layer 1004, and a second N-electrode layer 1006. In the side view, the second P-electrode layer 1005 and the second N-electrode layer 1004, or the second N-electrode layer 1006, are located in different planes. For example, Figure 5 In this configuration, the second P-electrode layer 1005 may be located on the contact layer 304. The second N-electrode layer 1004 and the second N-electrode layer 1006 may be located on the boundary line 501.

[0069] In other embodiments, the output direction of the signal light is at an angle of 4 to 15 degrees to the first direction. Specifically, when the output direction of the signal light is perpendicular to the output end face (the left end face of the electroabsorption modulator region), the signal light will produce end face reflection at the output end face. End face reflection will affect the characteristics of the laser region, such as causing a drift in the lasing wavelength of the laser region or causing deterioration of the eye diagram of the electroabsorption modulator region. Figure 2 As shown, the first and second ridge waveguides are straight waveguides parallel to the Z-axis. In this application, the first ridge waveguide can be a curved waveguide. In this case, the first ridge waveguide bends towards the X-axis. The tangent of the curved first ridge waveguide on the output end face (the left end face of the electroabsorption modulator region) is the output direction of the signal light. There is an angle of 4 to 15 degrees between the output direction and the positive direction of the Z-axis (the first direction).

[0070] In other embodiments, as shown in the figure, when there is a misalignment between the first active layer and the second active layer in the Y-axis direction, there is a certain misalignment error range between the first active layer and the second active layer. Specifically, the projections of the first quantum well layer and the second quantum well layer onto a first plane have a common region. The first plane is perpendicular to the upper surface of the substrate, and the normal of the first plane is parallel to the propagation direction of the laser in the laser region. For example, the first plane can be plane 207 or plane 208.

[0071] In other embodiments, the length of the laser region is 400 micrometers to 2000 micrometers. According to the foregoing... Figure 2 As described in the paper on electro-absorption modulated lasers, by introducing a waveguide layer, the electro-absorption modulator region can introduce a portion of the laser light into the waveguide layer, thereby increasing the laser power when the electro-absorption modulator region reaches saturation. Therefore, this application can increase the output power of the laser region. Generally, the longer the laser region, the greater its output power. In practical applications, the length of the laser region is typically less than 400 micrometers. This application limits the length of the laser region to 400 micrometers to 2000 micrometers.

[0072] The electro-absorption modulated laser has been described above. In this application, the electro-absorption modulator region can introduce a portion of the laser light into the waveguide layer, thereby increasing the saturation absorption power of the electro-absorption modulator. Therefore, this application can improve the output power of the electro-absorption modulated laser.

[0073] The optical emitting component provided in this application is described below. Figure 11 This is a schematic diagram of the structure of the light emitting component provided in this application. Figure 11 As shown, the optical emitting component 1101 includes an electro-absorption modulated laser 1103 and a photodetector 102. The signal light generated by the electro-absorption modulated laser 1103 includes backlight and forward light. The electro-absorption modulated laser 1103 is used to output forward light. The photodetector 1102 is used to receive the backlight and convert it into an electrical signal. The electrical signal can be compared with the electrical modulation signal to determine whether the electro-absorption modulated laser 1103 is operating normally. Specifically, when the electrical signal and the electrical modulation signal are the same, it indicates that the electro-absorption modulated laser 1103 is operating normally; when the electrical signal and the electrical modulation signal are different, it indicates that the electro-absorption modulated laser 1103 is not operating normally.

[0074] The electroabsorption modulated laser 1103 can be referred to the aforementioned. Figures 2 to 4 , Figures 6 to 7 An electrically absorbed modulated laser according to any of the embodiments. For example, such as Figure 2 As shown, the electro-absorption modulated laser 1103 includes an electro-absorption modulator region and a laser region. A waveguide layer is included between the first active layer of the electro-absorption modulator region and the substrate. For example, as... Figure 6As shown, the electroabsorption modulator region of the electroabsorption modulated laser 1103 includes an upper cladding.

[0075] The optical emitting component of this application has been described above. The optical terminal provided in this application is described below. Figure 12 This is a schematic diagram of the structure of the optical terminal provided in this application. Figure 12 As shown, the optical terminal 1201 includes a processor 1202 and an optical transmitter 1203. Specifically, the optical terminal 1201 can be... Figure 1 The optical terminal 1201 is an OLT or optical terminal in the system. It should be understood that in practical applications, the optical terminal 1201 can also be a switch or a data center, etc.

[0076] The light emitting component 1203 can be referred to the above. Figure 12 The optical emitting component 1201 is described above. The electroabsorption modulated laser can be referred to in the preceding text. Figures 2 to 4 , Figures 6 to 7 The electroabsorption modulated laser is described in any of the embodiments. The processor 1202 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor 1202 may further include a hardware chip or other general-purpose processor. The aforementioned hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof.

[0077] The optical emitting component 1203 includes an electro-absorption modulated laser. The processor 1202 provides an electrical modulation signal to the electro-absorption modulated laser. The electro-absorption modulated laser modulates the laser beam according to the electrical modulation signal to obtain signal light. Specifically, the signal light can refer to forward light.

[0078] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. An electroabsorption modulated laser, characterized in that, include: The laser region, electrically isolated region, and electrically absorbed modulator region are located on the same semiconductor substrate; The electrically isolated region is disposed between the laser region and the electrically absorbed modulator region; The laser region is used to generate laser light, which is coupled into the electroabsorption modulator region connected to the laser region; The electro-absorption modulator region is used to modulate the laser to obtain signal light; The electro-absorption modulator region includes a first active layer and a waveguide layer, wherein the waveguide layer is disposed between the substrate and the first active layer; the electro-absorption modulator region is used to introduce a portion of the laser light into the waveguide layer; the refractive index of the waveguide layer is less than the refractive index of the first active layer; The electroabsorption modulator region has a ridge-shaped structure, and the electroabsorption modulator region includes a first part and a second part located below the first part, wherein the width of the second part is greater than the width of the first part; The first active layer belongs to the first part; The substrate belongs to the second part; The waveguide layer includes a first waveguide layer and a second waveguide layer, wherein the first waveguide layer belongs to the first part and the second waveguide layer belongs to the second part.

2. The electroabsorption modulated laser according to claim 1, characterized in that, The length of the electroabsorption modulator region is greater than 300 micrometers in a first direction, which is the propagation direction of the laser in the laser region.

3. The electroabsorption modulated laser according to claim 1 or 2, characterized in that, The electroabsorption modulator region includes a first P electrode and a first N electrode, wherein the first P electrode and the first N electrode are traveling wave electrode structures.

4. The electroabsorption modulated laser according to any one of claims 1 to 3, characterized in that, The waveguide layer includes an upper cladding layer and a core layer, with the upper cladding layer disposed between the first active layer and the core layer.

5. The electroabsorption modulated laser according to claim 4, characterized in that, The waveguide layer further includes a lower cladding layer disposed between the substrate and the core layer.

6. The electroabsorption modulated laser according to claim 4 or 5, characterized in that, The thickness of the upper cladding layer is between 0.01 micrometers and 5 micrometers.

7. The electroabsorption modulated laser according to any one of claims 4 to 6, characterized in that, The thickness of the waveguide layer is between 0.03 micrometers and 6 micrometers.

8. The electroabsorption modulated laser according to claim 1, characterized in that, The second part is a ridge-shaped structure, which includes a third part and a fourth part located below the third part. The width of the fourth part is greater than the width of the third part. The second waveguide layer belongs to the third part, and the substrate belongs to the fourth part.

9. The electroabsorption modulated laser according to claim 8, characterized in that, The difference between the width of the first part and the width of the third part is greater than 4 micrometers.

10. The electroabsorption modulated laser according to any one of claims 1 to 9, characterized in that, The first active layer includes a first quantum well layer, and the laser region includes a second active layer, which in turn includes a second quantum well layer. The projections of the first quantum well layer and the second quantum well layer onto the first plane have a common area. The first plane is perpendicular to the upper surface of the substrate, and the normal of the first plane is parallel to the propagation direction of the laser in the laser region.

11. The electroabsorption modulated laser according to any one of claims 1 to 10, characterized in that, The waveguide layer is made of indium gallium arsenide phosphide (InGaAsP) or indium gallium aluminum arsenide (InGaAlAs).

12. The electroabsorption modulated laser according to any one of claims 1 to 11, characterized in that, The waveguide layer extends to the boundary between the electrically isolated region and the laser region.

13. The electroabsorption modulated laser according to any one of claims 1 to 12, characterized in that, The length of the laser region is 400 micrometers to 2000 micrometers.

14. A light-emitting component, characterized in that, include: The photodetector and the electroabsorption modulated laser as described in any one of claims 1-13; The signal light generated by the electroabsorption modulated laser includes backlight and frontlight; The electro-absorption modulated laser is used to output the forward light; The photodetector is used to receive the backlight and convert the backlight into an electrical signal.

15. An optical terminal, characterized in that, include: Processor and light-emitting components; The optical emitting component includes the electro-absorption modulated laser as described in any one of claims 1-13; The processor is used to provide an electrical modulation signal for the electro-absorption modulated laser; The electro-absorption modulated laser is used to modulate the laser according to the electro-modulation signal to obtain signal light.

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