Optical module

Abstract

The invention provides an optical module which comprises a light source comprising a laser assembly, the laser assembly comprises a semiconductor gain chip and a wavelength tuning chip which form a resonant cavity, and the wavelength tuning chip comprises at least one micro-ring filter. The at least one micro-ring filter is used for screening out a light beam with a specific wavelength from light beams emitted by the semiconductor gain chip, and comprises a silicon substrate, a covering layer arranged on the silicon substrate, a silicon waveguide ridge region positioned in the covering layer, a first flat plate region and a second flat plate region which are positioned on two sides of the silicon waveguide ridge region, and a contact electrode; an N-type doped region is arranged in the first flat plate region, a P-type doped region is arranged in the second flat plate region, the P-type doped region and the N-type doped region form a PN junction electrically connected with the contact electrode, and electron hole pairs in the silicon waveguide ridge region, the first flat plate region and the second flat plate region can be absorbed by applying reverse bias voltage to the PN junction. The PN junctions are additionally arranged on the two sides of the ridge region of the silicon waveguide, the nonlinear effect problem of the resonant cavity is solved, and the wavelength oscillation phenomenon is eliminated.

Description

Technical Field

[0001] The present disclosure relates to the field of optical communication technology, and in particular to an optical module. Background Art

[0002] Optical communication technology is used in new services and application models such as cloud computing, mobile Internet, and video. In optical communication, optical modules are devices that realize photoelectric signal conversion and are one of the key components in optical communication equipment.

[0003] With the development of coherent optical communication technology, high-performance tunable lasers have become increasingly indispensable. Tunable lasers generally include a spot coupler, a beam splitter, and two silicon microring filters with different circumferences. The spot coupler is used to couple with an external gain chip to provide optical gain for the entire laser resonant cavity; the beam splitter is used to split the main path and enter the two microring filters respectively. By adjusting the circumference of the two microring filters, the requirements of different wavelength tuning ranges can be met, thereby realizing the wavelength tunable function.

[0004] However, due to the two-photon absorption effect of silicon materials, especially when silicon microrings are used as laser resonant cavities and the internal optical power is very high, the two-photon absorption effect will be very significant, causing unstable oscillations in the laser output wavelength, limiting its application in practical scenarios. Summary of the invention

[0005] The embodiments of the present disclosure provide an optical module to solve the nonlinear effect problem of a silicon optical resonator as a laser resonant cavity under high optical power, and realize a high optical power, narrow linewidth, and widely adjustable laser.

[0006] In a first aspect, the present disclosure provides an optical module, comprising:

[0007] Circuit boards;

[0008] A light source, comprising a laser component, the laser component is electrically connected to the circuit board, the laser component comprises a semiconductor gain chip and a wavelength tuning chip, the semiconductor gain chip is used to emit a light beam in a wavelength range, the wavelength tuning chip and the semiconductor gain chip form a resonant cavity; wherein the wavelength tuning chip comprises:

[0009] An input coupler, used to receive the light beam emitted by the semiconductor gain chip and transmit a light beam of a specific wavelength to the semiconductor gain chip;

[0010] a power splitter connected to the input coupler, the power splitter being used to split the light beam input by the input coupler;

[0011] At least one micro-ring filter is connected to the output end of the power divider, and the micro-ring filter is used to filter out a light beam of a specific wavelength from the light beams in the wavelength range; wherein the micro-ring filter comprises:

[0012] Silicon substrate;

[0013] A covering layer is arranged on the silicon substrate along the epitaxial growth direction;

[0014] A silicon waveguide ridge region, located in the cover layer, the silicon waveguide ridge region is used to transmit the light beam and generate electron-hole pairs when transmitting the light beam;

[0015] A first slab region, located at one side of the silicon waveguide ridge region, wherein an N-type doped region is disposed in the first slab region;

[0016] A second slab region is located at the other side of the silicon waveguide ridge region, wherein a P-type doping region is provided in the second slab region, wherein the P-type doping region and the N-type doping region form a PN junction, wherein the PN junction is used to absorb electron-hole pairs in the silicon waveguide ridge region, the first slab region and the second slab region;

[0017] A contact electrode is located in the cover layer, and the contact electrode is electrically connected to the P-type doping region and the N-type doping region to provide a reverse bias voltage to the PN junction.

[0018] In a second aspect, the present disclosure provides an optical module, including:

[0019] Circuit boards;

[0020] A light source, comprising a laser component, the laser component is electrically connected to the circuit board, the laser component comprises a semiconductor gain chip and a wavelength tuning chip, the semiconductor gain chip is used to emit a light beam in a wavelength range, the wavelength tuning chip and the semiconductor gain chip form a resonant cavity; wherein the wavelength tuning chip comprises:

[0021] An input coupler, used to receive the light beam emitted by the semiconductor gain chip and transmit a light beam of a specific wavelength to the semiconductor gain chip;

[0022] a power splitter connected to the input coupler, the power splitter being used to split the light beam input by the input coupler;

[0023] At least one micro-ring filter is connected to the output end of the power divider, and the micro-ring filter is used to filter out a light beam of a specific wavelength from the light beams in the wavelength range; wherein the micro-ring filter comprises:

[0024] A silicon waveguide ridge region, used for transmitting a light beam and generating electron-hole pairs when transmitting the light beam;

[0025] A first slab region, located outside the silicon waveguide ridge region, the first slab region surrounds the silicon waveguide ridge region, an N-type doped region is disposed in the first slab region, and the N-type doped region surrounds the silicon waveguide ridge region;

[0026] A second slab region is located inside the silicon waveguide ridge region, the silicon waveguide ridge region surrounds the second slab region, a P-type doping region is provided in the second slab region, the silicon waveguide ridge region surrounds the P-type doping region, the P-type doping region and the N-type doping region form a PN junction, and the PN junction is used to absorb electron-hole pairs in the silicon waveguide ridge region, the first slab region and the second slab region;

[0027] A contact electrode is electrically connected to the P-type doping region and the N-type doping region to provide a reverse bias voltage to the PN junction.

[0028] It can be seen from the above embodiments that the optical module provided by the embodiments of the present disclosure includes a circuit board and a light source, the light source includes a laser component, the laser component is electrically connected to the circuit board, so that the laser component generates a light beam of a specific wavelength; the laser component includes a semiconductor gain chip and a wavelength tuning chip, the semiconductor gain chip is used to emit a light beam in a wavelength range, the wavelength tuning chip and the semiconductor gain chip form a resonant cavity, the wavelength tuning chip is used to screen out a light beam of a specific wavelength from the light beam in the wavelength range, so as to realize the wavelength tunable function of the laser component; the wavelength tuning chip includes an input coupler, a power divider and at least one microring filter, the input coupler is used to receive the light beam emitted by the semiconductor gain chip, the power divider is used to split the light beam input by the input coupler, the split light enters at least one microring filter, the microring filter is used to screen out a light beam of a specific wavelength from the light beam in the wavelength range; the microring filter includes a silicon substrate, a covering layer, a silicon waveguide ridge region, a first flat plate region, a second flat plate region and a contact electrode, the covering layer is arranged along the epitaxial The growth direction is set on the silicon substrate, the silicon waveguide ridge region is located in the covering layer, the silicon waveguide ridge region is used to transmit the light beam, and when the light beam is transmitted, electron-hole pairs are generated in the silicon waveguide ridge region, the first flat plate region and the second flat plate region; the first flat plate region and the second flat plate region are located on both sides of the silicon waveguide ridge region, an N-type doping region is arranged in the first flat plate region, and a P-type doping region is arranged in the second flat plate region, and the P-type doping region and the N-type doping region form a PN junction; the contact electrode is located in the covering layer, and the contact electrode is electrically connected to the P-type doping region and the N-type doping region to apply voltage to the PN junction to generate an electric field, and the silicon waveguide ridge region, the first flat plate region and the second flat plate region are located in the electric field formed by the PN junction, so that the PN junction can quickly absorb the electron-hole pairs generated by the two-photon absorption effect, and can avoid the heat generated by the electron-hole pair load to affect the refractive index of the resonant cavity, thereby being able to eliminate the wavelength oscillation phenomenon caused by the two-photon absorption effect, and realize a high-power, narrow-linewidth, and wide-adjustable silicon optical integrated laser, which is convenient for application in coherent optical communication, laser radar, sensing and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required to be used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not intended to limit the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0030] Figure 1 A partial structural diagram of an optical communication system provided according to some embodiments of the present disclosure;

[0031] Figure 2 A partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0032] Figure 3 A structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0033] Figure 4 An exploded view of an optical module provided according to some embodiments of the present disclosure;

[0034] Figure 5 A partial structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0035] Figure 6 A structural diagram of a light source assembly in an optical module provided according to some embodiments of the present disclosure;

[0036] Figure 7 An exploded view of a light source assembly in an optical module provided according to some embodiments of the present disclosure;

[0037] Figure 8 is a cross-sectional view of a light source assembly in a light module provided according to some embodiments of the present disclosure;

[0038] Fig. 9 A schematic diagram of a wavelength tuning chip in an optical module provided according to some embodiments of the present disclosure;

[0039] Fig.10 A working principle diagram of a wavelength tuning chip in an optical module provided according to some embodiments of the present disclosure;

[0040] Fig.11 A structural diagram of a micro-ring filter in an optical module provided according to some embodiments of the present disclosure;

[0041] Fig.12A cross-sectional view of a micro-ring filter in an optical module provided according to some embodiments of the present disclosure;

[0042] Fig.13 A light path diagram of a light source assembly in an optical module provided according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings to clearly and in detail describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0044] In optical communication technology, in order to establish information transmission between information processing devices, it is necessary to load information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When optical signals are transmitted in information transmission equipment, the loss of optical power can be reduced, so high-speed, long-distance, and low-cost information transmission can be achieved. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment usually includes optical network terminals (Optical Network Unit, ONU), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment usually includes optical fibers and optical waveguides.

[0045] The optical module can realize the mutual conversion between optical signals and electrical signals between information processing equipment and information transmission equipment. For example, at least one of the optical signal input end or the optical signal output end of the optical module is connected to an optical fiber, and at least one of the electrical signal input end or the electrical signal output end of the optical module is connected to an optical network terminal; the first optical signal from the optical fiber is transmitted to the optical module, and the optical module converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the optical network terminal; the second electrical signal from the optical network terminal is transmitted to the optical module, and the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber. Since multiple information processing devices can transmit information through electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, and all information processing devices do not need to be directly connected to the optical module. Here, the information processing device directly connected to the optical module is called the upper computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module can be called an optical port, and the electrical signal input end or the electrical signal output end of the optical module can be called an electrical port.

[0046] Figure 1 FIG. 1 is a partial structural diagram of an optical communication system provided according to some embodiments of the present disclosure. Figure 1As shown, the optical communication system mainly includes a remote information processing device 1000 , a local information processing device 2000 , a host computer 100 , an optical module 200 , an optical fiber 101 and a network cable 103 .

[0047] One end of the optical fiber 101 extends toward the remote information processing device 1000, and the other end of the optical fiber 101 is connected to the optical module 200 through the optical port of the optical module 200. The optical signal can be totally reflected in the optical fiber 101, and the propagation of the optical signal in the total reflection direction can almost maintain the original optical power. The optical signal undergoes multiple total reflections in the optical fiber 101 to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or to transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance, low-power loss information transmission.

[0048] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 are detachably connected or fixedly connected to the optical module 200. The host computer 100 is configured to provide data signals to the optical module 200, receive data signals from the optical module 200, or monitor or control the working state of the optical module 200.

[0049] The host computer 100 includes a substantially rectangular housing and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to connect to the optical module 200 so that the host computer 100 and the optical module 200 establish a unidirectional or bidirectional electrical signal connection.

[0050] The host computer 100 also includes an external electrical interface, which can be connected to an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104, and the network cable interface 104 is configured to access the network cable 103 so that the host computer 100 establishes a unidirectional or bidirectional electrical signal connection with the network cable 103. One end of the network cable 103 is connected to the local information processing device 2000, and the other end of the network cable 103 is connected to the host computer 100, so as to establish an electrical signal connection between the local information processing device 2000 and the host computer 100 through the network cable 103. For example, the third electrical signal sent by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103, and the host computer 100 generates a second electrical signal according to the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200, and the optical module 200 converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber 101, and the second optical signal is transmitted to the remote information processing device 1000 in the optical fiber 101. For example, the first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101, and the first optical signal from the optical fiber 101 is transmitted to the optical module 200, and the optical module 200 converts the first optical signal into a first electrical signal, and the optical module 200 transmits the first electrical signal to the host computer 100, and the host computer 100 generates a fourth electrical signal according to the first electrical signal, and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that the optical module is a tool for realizing the mutual conversion between optical signals and electrical signals. During the conversion process between the optical signals and electrical signals, the information does not change, but the encoding and decoding methods of the information can change.

[0051] In addition to the optical network terminal, the host computer 100 also includes an optical line terminal (OLT), an optical network device (ONT), or a data center server.

[0052] Figure 2 1 is a partial structural diagram of a host computer provided according to some embodiments of the present disclosure. In order to clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 Only the structure of the host computer 100 related to the optical module 200 is shown. Figure 2 As shown, the host computer 100 further includes a PCB circuit board 105 disposed in the housing, a cage 106 disposed on the surface of the PCB circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access the electrical port of the optical module 200; the heat sink 107 has a protruding structure such as fins to increase the heat dissipation area.

[0053] The optical module 200 is inserted into the cage 106 of the host computer 100, and the cage 106 fixes the optical module 200. The heat generated by the optical module 200 is transferred to the cage 106 and then diffused through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 establishes a bidirectional electrical signal connection with the host computer 100. In addition, the optical port of the optical module 200 is connected to the optical fiber 101, so that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101.

[0054] Figure 3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure, Figure 4 FIG. 1 is an exploded view of an optical module provided according to some embodiments of the present disclosure. Figure 3 and Figure 4 As shown, the optical module 200 includes a shell, a circuit board 300 disposed in the shell, a light source 900, a coherent optical chip, a transmitting optical fiber adapter 700 and a receiving optical fiber adapter 800, but the present disclosure is not limited thereto.

[0055] The housing comprises an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing having two openings 204 and 205 . The outer contour of the housing is generally a square body.

[0056] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and arranged perpendicular to the bottom plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0057] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and vertically arranged with the bottom plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and vertically arranged with the cover plate 2011, and the two upper side plates are combined with the two lower side plates 2022 to realize that the upper shell 201 covers the lower shell 202.

[0058] The direction of the line connecting the two openings 204 and 205 may be consistent with the length direction of the optical module 200, or may be inconsistent with the length direction of the optical module 200. For example, the opening 204 is located at the end of the optical module 200 ( Figure 3 The opening 205 is also located at the end of the optical module 200 ( Figure 3Alternatively, the opening 204 is located at the end of the optical module 200, and the opening 205 is located at the side of the optical module 200. The opening 204 is an electrical port, and the gold finger of the circuit board 300 extends from the electrical port and is inserted into the electrical connector of the host computer 100; the opening 205 is an optical port, which is configured to access the external optical fiber 101 so that the optical fiber 101 is connected to the optical transceiver component 900 in the optical module 200.

[0059] The assembly method of combining the upper housing 201 and the lower housing 202 is adopted, so that the circuit board 300, the light source 900, the coherent optical chip, the transmitting optical fiber adapter 700, the receiving optical fiber adapter 800, etc. can be installed in the above housing, and the above components can be packaged and protected by the upper housing 201 and the lower housing 202. In addition, when assembling the circuit board 300, the light source 900, the coherent optical chip, the transmitting optical fiber adapter 700, the receiving optical fiber adapter 800, etc., the assembly method of the upper housing 201 and the lower housing 202 is adopted, which is convenient for the deployment of the positioning components, heat dissipation components and electromagnetic shielding components of these components, and is conducive to the automated production.

[0060] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials to facilitate electromagnetic shielding and heat dissipation.

[0061] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside its housing. The unlocking component 600 is configured to achieve a fixed connection between the optical module 200 and the host computer 100, or to release the fixed connection between the optical module 200 and the host computer 100.

[0062] For example, the unlocking component 600 is located on the outside of the two lower side plates 2022 of the lower housing 202, and includes a snap-fit ​​component that matches the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the snap-fit ​​component of the unlocking component 600 fixes the optical module 200 in the cage 106; when the unlocking component 600 is pulled, the snap-fit ​​component of the unlocking component 600 moves accordingly, thereby changing the connection relationship between the snap-fit ​​component and the host computer, so as to release the fixation of the optical module 200 and the host computer, so that the optical module 200 can be pulled out of the cage 106.

[0063] The circuit board 300 includes circuit traces, electronic components and chips, etc. The electronic components and chips are connected according to the circuit design through the circuit traces to realize the functions of power supply, electrical signal transmission and grounding. The electronic components may include capacitors, resistors, transistors, metal-oxide-semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), etc. The chips may include microcontroller units (Microcontroller Unit, MCU), laser driver chips, transimpedance amplifiers (Transimpedance Amplifier, TIA), limiting amplifiers (Limiting amplifier, LA), clock and data recovery chips (Clock and Data Recovery, CDR), power management chips, digital signal processing (Digital Signal Processing, DSP) chips.

[0064] The circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also realize the load-bearing function. For example, the rigid circuit board can stably carry the above-mentioned electronic components and chips; the rigid circuit board can also be inserted into the electrical connector in the cage 106 of the host computer 100.

[0065] The circuit board 300 also includes a gold finger formed on the end surface thereof, and the gold finger is composed of a plurality of independent pins. The circuit board 300 is inserted into the cage 106, and the gold finger is connected to the electrical connector in the cage 106. The gold finger can be provided on the surface of only one side of the circuit board 300 (for example, Figure 4 The upper surface shown in the figure) can also be set on the upper and lower surfaces of the circuit board 300 to provide a larger number of pins, so as to adapt to occasions where the number of pins is large. The gold finger is configured to establish an electrical connection with the host computer to achieve power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, data signal transmission, etc. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement rigid circuit boards.

[0066] In some embodiments, the light source 900 and the coherent optical chip are physically separated from the circuit board 300 and then electrically connected to the circuit board 300 via a flexible circuit board or an electrical connector.

[0067] In some embodiments, the light source 900 and the coherent optical chip may be directly disposed on the circuit board 300. For example, the light source 900 and the coherent optical chip may be disposed on the surface of the circuit board 300 or on the side of the circuit board 300.

[0068] Figure 5FIG. 1 is a partial structural diagram of an optical module provided according to some embodiments of the present disclosure. Figure 5 As shown, the light source 900 is electrically connected to the circuit board 300, and the light source 900 is used to emit a light beam of a specific wavelength. The light source 900 may include a semiconductor gain chip and a wavelength tuning chip, the semiconductor gain chip emits a light beam in a wavelength range, the wavelength tuning chip selects a light beam of a specific wavelength from the light beam in a wavelength range, the wavelength tuning chip and the semiconductor gain chip form a resonant cavity, and the light beam of a specific wavelength is reflected back and forth between the wavelength tuning chip and the semiconductor gain chip, so that the light beam of a specific wavelength is stably output by the semiconductor gain chip.

[0069] The coherent optical chip 1100 is installed on the circuit board 300. The coherent optical chip 1100 is used to realize the conversion of high-speed optical and electrical signals, that is, the coherent optical chip includes an optical transmission interface, an optical receiving interface and a local oscillator optical interface. The optical transmission interface extends a first optical fiber, the optical receiving interface extends a second optical fiber, and the local oscillator optical interface extends a third optical fiber. The optical transmission interface is connected to the transmission optical fiber adapter 700 through the first optical fiber, the optical receiving interface is connected to the receiving optical fiber adapter 800 through the second optical fiber, and the local oscillator optical interface is connected to the light source 900 through the third light. The coherent optical chip 1100 is also connected to the DSP chip 302.

[0070] The narrow linewidth and high-power laser emitted by the light source 900 is input into the coherent optical chip 1100 through the local oscillator optical interface. The laser is split into beams inside the coherent optical chip 1100, and one beam is used as a transmission light beam and enters the coherent modulator inside the coherent optical chip. The electric-optical signal conversion is realized under the high-speed electrical signal drive of the DSP chip 302. The converted high-speed optical signal is output from the optical transmission interface and transmitted to the transmission optical fiber adapter 700 through the first optical fiber, thereby realizing the emission of coherent light.

[0071] The other beam is used as a local oscillator beam to receive the high-speed optical signal transmitted by the optical fiber adapter 800 and input into the coherent optical chip 1100 from the optical receiving interface. The local oscillator beam and the high-speed optical signal are coherently demodulated, and the demodulated electrical signal enters the DSP chip 302 for signal processing, thereby realizing the reception of coherent light.

[0072] In some embodiments, the narrow line width and high power laser emitted by the light source 900 is a laser of a specific wavelength.

[0073] Figure 6 is a structural diagram of a light source assembly in an optical module provided according to some embodiments of the present disclosure, Figure 7 FIG. 1 is an exploded view of a light source assembly in an optical module according to some embodiments of the present disclosure. Figure 6 and Figure 7As shown, the light source 900 includes a laser component 901 and an internal optical fiber adapter 902. The laser component 901 is used to generate laser light of a specific wavelength. The internal optical fiber adapter 902 is connected to the local oscillator optical interface of the coherent optical chip 1100 through the local oscillator optical fiber, so that the laser light generated by the laser component 901 is input to the coherent optical chip 1100 through the internal optical fiber adapter 902 and the local oscillator optical fiber.

[0074] The laser assembly 901 includes a tube shell 9011, an electrical connector 9012 and a cover plate 9013. The tube shell 9011 includes a bottom plate, a first side plate, a second side plate, a third side plate and a fourth side plate. The first side plate, the second side plate, the third side plate and the fourth side plate are connected to the bottom plate. The first side plate and the second side plate are arranged opposite to each other, and the third side plate and the fourth side plate are arranged opposite to each other. In this way, the bottom plate, the first side plate, the second side plate, the third side plate and the fourth side plate constitute a shell with a top opening.

[0075] The third side plate faces the transmitting optical fiber adapter 700, and the fourth side plate faces the coherent optical chip 1100. An opening groove is formed on the third side plate, and a mounting groove is formed on the fourth side plate. The opening groove is connected to the mounting groove, so that the opening groove and the mounting groove form an L-shaped groove. The electrical connector 9012 is an L-shaped structure, and the electrical connector 9012 is inserted into the L-shaped groove of the tube shell 9011 to achieve the connection between the electrical connector 9012 and the tube shell 9011.

[0076] The electrical connector 9012 has a plurality of metal pins formed on the side surface outside the tube shell 9011, and the plurality of metal pins are welded to the pin pads on the circuit board 300 to realize the electrical connection between the electrical connector 9012 and the circuit board 300; the electrical connector 9012 has a pad formed on the side surface inside the tube shell 9011.

[0077] In some embodiments, a through hole is formed on the fourth side plate, and one end of the internal optical fiber adapter 902 is inserted into the through hole to achieve assembly of the internal optical fiber adapter 902 and the tube shell 9011 .

[0078] A housing cavity 9014 is formed in the tube shell 9011, and an optical group 903 is installed in the housing cavity 9014. The optical group 903 is electrically connected to the solder pad on the electrical connector 9012 so that the optical group 903 generates a light beam of a specific wavelength; the light beam of the specific wavelength generated by the optical group 903 is transmitted to the local oscillator optical fiber via the internal optical fiber adapter 902, and then emitted into the coherent optical chip 1100 via the local oscillator optical fiber.

[0079] In some embodiments, the optical group 903 includes a wavelength tuning chip 9031, a semiconductor gain chip 9032, a first lens 9033, an isolator 9034, a second lens 9035, a semiconductor amplifier chip 9036, a third lens 9037, a beam splitter 9038, a power monitor 9039 and a fourth lens 9040, wherein:

[0080] The semiconductor gain chip 9032 is located between the electrical connector 9012 and the internal optical fiber adapter 902 . The semiconductor gain chip 9032 is used to emit a light beam within a wavelength range.

[0081] The wavelength tuning chip 9031 is located between the electrical connector 9012 and the semiconductor gain chip 9032. The wavelength tuning chip 9031 is electrically connected to the pad on the electrical connector 9012 through wire bonding. The wavelength tuning chip 9031 is used to receive a light beam in a wavelength range and filter out a light beam of a specific wavelength from the light beam in a wavelength range. The wavelength tuning chip 9031 is also used to inject a light beam of a specific wavelength into the semiconductor gain chip 9032. The wavelength tuning chip 9031 and the semiconductor gain chip 9032 form a resonant cavity. The light beam of a specific wavelength is reflected back and forth between the wavelength tuning chip 9031 and the semiconductor gain chip 9032, so that the characteristic wavelength light beam is stably output by the semiconductor gain chip. In some embodiments, the wavelength tuning chip 9031 is a silicon photonic chip.

[0082] In some embodiments, the semiconductor gain chip 9032 is made of III-V group gain materials and includes two optical waveguide end faces, one of which adopts an inclined waveguide structure and is coated with an anti-reflection film to achieve extremely low light field reflectivity, and is used to couple with the input coupler of the wavelength tuning chip 9031, so that a specific wavelength light beam can be reflected back and forth between the semiconductor gain chip 9032 and the wavelength tuning chip 9031; the other end face adopts a straight waveguide structure and is coated with a reflective film with a certain reflectivity to achieve light field reflection and transmission functions, so that when the specific wavelength light beam oscillates to a certain extent, the semiconductor gain chip 9032 can emit a specific wavelength light beam.

[0083] The fourth lens 9040 is located between the wavelength tuning chip 9031 and the semiconductor gain chip 9032 . The fourth lens 9040 is used to collimate the light beam within a wavelength range output by the semiconductor gain chip 9032 , so that the light beam output by the semiconductor gain chip 9032 is incident into the wavelength tuning chip 9031 .

[0084] The first lens 9033 is located between the semiconductor gain chip 9032 and the internal optical fiber adapter 902. The first lens 9033 is used to collimate the specific wavelength light beam output by the semiconductor gain chip 9032. In some embodiments, the first lens 9033 is a collimating lens.

[0085] The isolator 9034 is located between the first lens 9033 and the internal optical fiber adapter 902 . The isolator 9034 is used to prevent the light beam incident on the internal optical fiber adapter 902 from being reflected back into the semiconductor gain chip 9032 , so as to reduce the influence of the light path reflection and further reduce the noise level of the light source 900 .

[0086] The second lens 9035 is located between the isolator 9034 and the internal fiber adapter 902. The second lens 9035 is used to converge the light beam with a specific wavelength passing through the isolator 9034 to the internal fiber adapter 902. In some embodiments, the second lens 9035 is a convergent lens.

[0087] The semiconductor amplifier chip 9036 is located between the second lens 9035 and the internal optical fiber adapter 902. The second lens 9035 converges the specific wavelength light beam to the semiconductor amplifier chip 9036. The semiconductor amplifier chip 9036 is used to amplify the power of the specific wavelength light beam to increase the optical power of the specific wavelength light beam.

[0088] The third lens 9037 is located between the semiconductor amplifier chip 9036 and the internal optical fiber adapter 902. The third lens 9037 is used to collimate the specific wavelength light beam after power amplification. In some embodiments, the third lens 9037 is a collimating lens.

[0089] The beam splitter 9038 is located between the third lens 9037 and the internal optical fiber adapter 902 . The beam splitter 9038 is used to split the light beam of a specific wavelength into two paths, one path is coupled to the power monitor 9039 , and the other path is coupled to the internal optical fiber adapter 902 .

[0090] The power monitor 9039 is located between the beam splitter 9038 and the first side plate of the tube shell 9011. The power monitor 9039 is used to monitor the optical power of the specific wavelength light beam in real time. When the optical power of the specific wavelength light beam is less than the preset optical power range, the amplification factor of the semiconductor amplifier chip 9036 is increased so that the optical power of the specific wavelength light beam is within the preset optical power range; when the optical power of the specific wavelength light beam is greater than the preset optical power range, the amplification factor of the semiconductor amplifier chip 9036 is reduced so that the optical power of the specific wavelength light beam is within the preset optical power range.

[0091] Figure 8 FIG. 1 is a cross-sectional view of a light source assembly in a light module according to some embodiments of the present disclosure. Figure 8As shown, in some embodiments, a semiconductor cooler 905 is further provided in the accommodating cavity 9014, a substrate 904 is mounted on the cooling surface of the semiconductor cooler 905, and the optical group 903 is mounted on the substrate 904. The temperature of the wavelength tuning chip 9031 can be controlled by the semiconductor cooler 905 to adjust the wavelength of the light beam output by the wavelength tuning chip 9031, so that the wavelength tuning chip 9031 outputs a light beam of a specific wavelength.

[0092] An optical window 9021 and a fifth lens 9022 are provided in the internal optical fiber adapter 902. The optical window 9021 is close to the beam splitter 9038. A path of light emitted from the beam splitter 9038 is incident into the internal optical fiber adapter 902 through the optical window 9021, and then focused and coupled to the optical fiber core in the internal optical fiber adapter 902 through the fifth lens 9022, so as to couple the specific wavelength light beam emitted by the optical group 903 to the internal optical fiber adapter 902.

[0093] In some embodiments, in order to enable the optical group 903 to generate a light beam of a specific wavelength, a plurality of micro-ring filters are integrated in the wavelength tuning chip 9031 , and the wavelength tunable function of the wavelength tuning chip 9031 is realized by using the vernier effect of the plurality of different micro-ring filters.

[0094] Fig. 9 FIG. 1 is a schematic diagram of a wavelength tuning chip in an optical module according to some embodiments of the present disclosure. Fig. 9 As shown, an input coupler 906, a phase modulator 907, a power divider 908, a first micro-ring filter 909 and a second micro-ring filter 910 are formed in the wavelength tuning chip 9031. The input coupler 906, the phase modulator 907, the power divider 908, the first micro-ring filter 909 and the second micro-ring filter 910 are all formed by the wavelength tuning chip 9031 using a complementary metal oxide semiconductor (CMOS) process.

[0095] The input coupler 906 is disposed at one end face of the wavelength tuning chip 9031 . The input coupler 906 is used to receive a light beam in a wavelength range emitted by the semiconductor gain chip 9032 , and is also used to output a specific wavelength light beam screened by the wavelength tuning chip 9031 to the outside of the wavelength tuning chip 9031 .

[0096] The specific wavelength light beam is reflected back and forth between the wavelength tuning chip 9031 and the semiconductor gain chip 9032 , so that the semiconductor gain chip 9032 and the wavelength tuning chip 9031 form a resonant cavity, and the specific wavelength light beam is stably output by the semiconductor gain chip 9032 .

[0097] In some embodiments, the input coupler 906 adopts an inclined waveguide design, that is, the optical waveguide of the input coupler 906 is set at a certain angle to the end face of the wavelength tuning chip 9031. In this way, when the light beam emitted by the semiconductor gain chip 9032 enters the input coupler 906 from the upper right, part of the light beam may be reflected at the end face of the wavelength tuning chip 9031. The reflected light beam will be emitted from the upper right instead of returning to the semiconductor gain chip 9032 along the original path, thereby reducing the influence of the end face reflected light of the wavelength tuning chip 9031 on the semiconductor gain chip 9032.

[0098] Since one end face of the semiconductor gain chip 9032 adopts an inclined waveguide structure, the input coupler 906 and the inclined waveguide structure of the semiconductor gain chip 9032 are arranged in parallel in the optical path direction, so that the semiconductor gain chip 9032 matches the wavelength tuning chip 9031, reducing the reflection of the light field of the input coupler 906, so as to improve the quality of the light beam.

[0099] In some embodiments, the input coupler 906 and the tilted waveguide structure of the semiconductor gain chip 9032 may be arranged in parallel in the optical path direction, so that the output angle of the specific wavelength light beam output by the input coupler 906 is 20°.

[0100] The phase modulator 907 is located between the input coupler 906 and the power divider 908. The phase modulator 907 is used to adjust the wavelength of the light beam supported by the resonant cavity so that the specific wavelength light beam screened by the first microring filter 909 and the second microring filter 910 coincides with the light beam in the resonant cavity.

[0101] In some embodiments, a heater is provided on the phase modulator 907. By changing the heater, the cavity length of the phase modulator 907 is changed, and then the cavity length of the resonant cavity is changed, so that a light beam of a certain wavelength supported by the resonant cavity coincides with the light beam of a specific wavelength screened out by the two microring resonant cavities.

[0102] The power divider 908 is located between the phase modulator and the first micro-ring filter 909. The power divider 908 is used for light splitting, dividing the light beam output by the phase modulator 907 into two light beams; the power divider 908 is also used for light combining, combining the light beams of specific wavelengths screened out by the first micro-ring filter 909 and the second micro-ring filter 910.

[0103] A power divider generally refers to a power distributor. A power divider is a device that divides one input signal energy into two or more outputs with equal or unequal energy. It can also combine the energy of multiple signals into one output, which is also called a combiner.

[0104] The power divider 908 divides the light beam outputted by the phase modulator 907 into two light beams, wherein one light beam first passes through the first micro-ring filter 909 and then through the second micro-ring filter 910, and the other light beam first passes through the second micro-ring filter 910 and then through the first micro-ring filter 909. The power divider 908 can also combine the light beam of a specific wavelength first passed through the first micro-ring filter 909 and then through the second micro-ring filter 910 and the light beam of a specific wavelength first passed through the second micro-ring filter 910 and then through the first micro-ring filter 909 into one light beam of a specific wavelength.

[0105] In some embodiments, the splitting ratio of the power divider 908 may be 50%:50%, that is, the power divider 908 divides one light beam into two light beams at a ratio of 50%:50%, and the two light beams are filtered by the first microring filter 909 and the second microring filter 910 and then returned to the power divider 908. According to the reversible principle of the optical path, theoretically, except for the loss through the first microring filter 909, the second microring filter 910 and the optical waveguide, the other losses are zero.

[0106] The splitting ratio of the power divider 908 can also be 20%:80%. The power divider 908 divides one light beam into two light beams at a ratio of 20%:80%. The two light beams are filtered by the first microring filter 909 and the second microring filter 910 and then returned to the power divider 908. According to the reversible principle of the optical path, theoretically, other losses except the losses passing through the first microring filter 909, the second microring filter 910 and the optical waveguide are greater than zero.

[0107] In some embodiments, in order to minimize beam loss, the splitting ratio of the power splitter is 50%:50%.

[0108] The first microring filter 909 cooperates with the second microring filter 910 to filter out a light beam of a specific wavelength from a light beam in a wavelength range emitted by the semiconductor gain chip 9032. The first microring filter 909 is coupled to the power divider 908 through a first straight optical waveguide, the first microring filter 909 is coupled to the second microring filter 910 through a second straight optical waveguide, and the second microring filter 910 is coupled to the power divider 908 through a third straight optical waveguide.

[0109] The first microring filter 909 and the second microring filter 910 are both microring structures, but they have different circumferences, so that the wavelengths of the light beams screened out by the first microring filter 909 and the second microring filter 910 are different. The two microring filters of different sizes have different mode wavelength intervals. The position of the mode wavelength can be adjusted by changing the refractive index of the resonant cavity by using the thermo-optical effect. Based on the vernier effect, a specific wavelength can be selected only when the mode wavelengths of the two microring filters coincide, so that the wavelength tuning chip 9031 outputs a specific wavelength light beam, thereby realizing the wavelength tunable function.

[0110] Fig.10 FIG. 1 is a working principle diagram of a wavelength tuning chip in an optical module according to some embodiments of the present disclosure. Fig.10 As shown, in some embodiments, the principle of the first micro-ring filter 909 and the second micro-ring filter 910 screening a light beam of a specific wavelength is:

[0111] A light beam in a wavelength range is incident through the input end of the first straight optical waveguide (the end close to the power divider 908). When the light beam is transmitted to the first coupling region between the first straight optical waveguide and the first microring filter 909, part of the light beam is coupled into the first microring filter 909, and the remaining part of the light beam is output from the output end of the first straight optical waveguide (the end away from the power divider 908). When the light beam propagating in the first microring filter 909 passes through the second coupling region formed by the second straight optical waveguide and the first microring filter 909, part of the light beam is coupled into the second straight optical waveguide, and the remaining part of the light beam is still propagating in the first microring filter 909. When the light beam propagating in the first microring filter 909 meets the resonance condition mλ=nl of the first microring filter 909, resonance occurs, thereby obtaining coherent enhancement, and the optical power of the light beam obtained by the second straight optical waveguide from the first microring filter 909 will also increase, and the light beam that does not meet the resonance condition is output at the output end of the first straight optical waveguide. Wherein, λ is the wavelength of the light beam, l is the circumference of the first microring filter, n is the effective refractive index of the first microring filter, and m is a positive integer. That is, only the light beam that meets the resonance condition of the first microring filter 909 can be screened out by the first microring filter 909 and coupled to the second straight optical waveguide.

[0112] When the light beam is transmitted to the third coupling region between the second straight optical waveguide and the second microring filter 910, part of the light beam is coupled into the second microring filter 910, and the remaining part of the light beam is output from the second output end of the second straight optical waveguide. When the light beam propagating in the second microring filter 910 passes through the fourth coupling region formed by the third straight optical waveguide and the second microring filter 910, part of the light beam is coupled into the third straight optical waveguide, and the remaining part of the light beam is still propagating in the second microring filter 910. When the light beam propagating in the second microring filter 910 meets the resonance condition mλ=nl of the second microring filter 910, resonance occurs to obtain coherent enhancement, and the optical power of the light beam obtained by the third straight optical waveguide from the second microring filter 910 will also increase, and the light that does not meet the resonance condition is output at the second output end of the second straight optical waveguide. Wherein, λ is the wavelength of the light beam, l is the circumference of the second microring filter, n is the effective refractive index of the second microring filter, and m is a positive integer. That is, only the light beam that meets the resonance condition of the second microring filter 910 can be screened out by the second microring filter 910 and coupled to the third straight optical waveguide. At this time, the light beam received by the third straight optical waveguide is a light beam with a specific wavelength.

[0113] The above is the process of filtering out a specific wavelength light beam by the first micro-ring filter 909 and then by the second micro-ring filter 910. Similarly, the process of filtering out a specific wavelength light beam by the second micro-ring filter 910 and then by the first micro-ring filter 909 is as follows:

[0114] A light beam in a wavelength range is incident through the input end (the end close to the power divider 908) of the third straight optical waveguide. When the light beam is transmitted to the fourth coupling region between the third straight optical waveguide and the second microring filter 910, part of the light beam is coupled into the second microring filter 910, and the remaining part of the light beam is output from the output end (the end away from the power divider 908) of the third straight optical waveguide. When the light beam propagating in the second microring filter 910 passes through the third coupling region formed by the second straight optical waveguide and the second microring filter 910, part of the light beam is coupled into the second straight optical waveguide, and the remaining part of the light beam is still propagating in the second microring filter 910. When the light beam propagating in the second microring filter 910 meets the resonance condition mλ=nl of the second microring filter 910, resonance occurs, thereby obtaining coherent enhancement, and the optical power obtained by the second straight optical waveguide from the second microring filter 910 will also increase, and the light that does not meet the resonance condition is output at the output end of the third straight optical waveguide.

[0115] When the light beam is transmitted to the second coupling region between the second straight optical waveguide and the first microring filter 909, part of the light beam is coupled into the first microring filter 909, and the remaining part of the light beam is output from the first output end of the second straight optical waveguide. When the light beam propagating in the first microring filter 909 passes through the first coupling region formed by the first straight optical waveguide and the first microring filter 909, part of the light beam is coupled into the first straight optical waveguide, and the remaining part of the light beam is still propagating in the first microring filter 909. When the light beam propagating in the first microring filter 909 meets the resonance condition mλ=nl of the first microring filter 909, resonance occurs to obtain coherent enhancement, and the optical power of the light beam obtained by the first straight optical waveguide from the first microring filter 909 will also increase, and the light that does not meet the resonance condition is output at the second output end of the second straight optical waveguide. At this time, the light beam received by the first straight optical waveguide is a light beam of a specific wavelength.

[0116] In some embodiments, the first microring filter 909 and the second microring filter 910 are both microring structures, but they have different circumferences. According to the resonance condition, the wavelengths of the light beams screened out by the first microring filter 909 and the second microring filter 910 are different. Based on the vernier effect, only when the light beam screened out by the first microring filter 909 coincides with the light beam screened out by the second microring filter 910, the light beam screened out by the wavelength tuning chip 9031 is a light beam of a specific wavelength.

[0117] The first microring filter 909 and the second microring filter 910 can adopt a strip waveguide or ridge waveguide structure. The requirements of different wavelength tuning ranges can be met by adjusting the circumference of the two microring filters. Usually, a heater is integrated above the microring filter, and the refractive index of the microring filter is changed by the heater, thereby achieving tuning of different working wavelengths.

[0118] The first micro-ring filter 909 and the second micro-ring filter 910 can filter a specific wavelength light beam from a light beam in a wavelength range emitted by the semiconductor gain chip 9032. This wavelength value is determined by the characteristics of the first micro-ring filter 909 and the second micro-ring filter 910. However, the resonant cavity composed of the semiconductor gain chip 9032 and the wavelength tuning chip 9031 will select and support multiple light beams of different wavelengths according to its own cavity structure. The multiple wavelengths of light beams supported by the resonant cavity do not necessarily coincide with the light beams of the specific wavelength filtered by the two micro-ring filters. If the multiple wavelengths of light beams supported by the resonant cavity do not coincide with the specific wavelength light beams filtered by the two micro-ring filters, the cavity length of the phase modulator 907 can be changed by changing the refractive index of the phase modulator 907, thereby changing the cavity length of the resonant cavity, so that a certain wavelength of light beam supported by the resonant cavity coincides with the specific wavelength light beam, so that the resonant cavity emits a specific wavelength light beam.

[0119] However, since the first microring filter 909 and the second microring filter 910 are silicon microrings, the silicon material has a large third-order nonlinear optical susceptibility, and the internal silicon waveguide may lead to an excessively high optical power density due to its own high refractive index difference and small cross-sectional size, resulting in a two-photon absorption effect (TPA) in the microring filter. In particular, when the silicon microring filter is used as a laser resonant cavity, the internal optical power is very high. At this time, the two-photon absorption effect will be very significant. The two-photon absorption effect will generate a large number of electron-hole pairs (free carriers). When the free carriers are absorbed, heat will be generated, which will in turn change the refractive index of the resonant cavity, thereby causing the output wavelength of the laser component 901 to have an unstable oscillation scene, limiting its application in actual scenarios.

[0120] Fig.11 is a structural diagram of a micro-ring filter in an optical module provided according to some embodiments of the present disclosure, Fig.12 FIG. 1 is a cross-sectional view of a micro-ring filter in an optical module according to some embodiments of the present disclosure. Fig.11 and Fig.12 As shown, in order to solve the nonlinear effect problem of the silicon optical resonator as a laser resonant cavity under high optical power, the microring filter adopts a ridge waveguide structure, and forms a PN junction by ion implantation in the flat plate area on both sides of the waveguide. By applying a reverse bias to the PN junction to form an electric field, the PN junction can quickly absorb the electron-hole pairs generated by the two-photon absorption effect, thereby eliminating the wavelength oscillation phenomenon of the laser component 901.

[0121] The first microring filter 909 and the second microring filter 910 have the same structure, but different circumferences. The requirements of different wavelength tuning ranges can be met by adjusting the circumferences of the two microring filters.

[0122] See also Fig.11 The first micro-ring filter 909 is a ring filter. When the ring filter is cross-sectioned, the ring filter includes a silicon waveguide ridge region 9104, a first flat region 9105, a second flat region 9106, and a contact electrode. The first flat region 9105 is located outside the silicon waveguide ridge region 9104, and the first flat region 9105 surrounds the silicon waveguide ridge region 9104; the second flat region 9106 is located inside the silicon waveguide ridge region 9104, and the silicon waveguide ridge region 9104 surrounds the second flat region 9106. In this way, from the inside to the outside, the second flat region 9106, the silicon waveguide ridge region 9104, and the first flat region 9105 are arranged in sequence.

[0123] An N-type doped region 9107 is arranged in the first flat region 9105, and the N-type doped region 9107 surrounds the silicon waveguide ridge region 9104; a P-type doped region 9108 is arranged in the second flat region 9106, and the silicon waveguide ridge region 9104 surrounds the P-type doped region 9108, so that the N-type doped region 9107 and the P-type doped region 9108 surround the silicon waveguide ridge region 9104.

[0124] The N-type doped region 9107 is electrically connected to the P-type doped region 9108 and the contact electrode so as to supply power to the N-type doped region 9107 and the P-type doped region 9108 through the contact electrode, so that a PN junction is formed between the N-type doped region 9107 and the P-type doped region 9108. The electric field formed by the PN junction surrounds the silicon waveguide ridge region 9104, so that the PN junction absorbs the electron-hole pairs in the silicon waveguide ridge region 9104, the first flat plate region 9105 and the second flat plate region 9106, thereby preventing the electron-hole pairs from generating heat to the load and affecting the refractive index of the resonant cavity, thereby eliminating the wavelength oscillation phenomenon caused by the two-photon absorption effect.

[0125] See also Fig.12 The first micro-ring filter 909 is a ring filter. When the first micro-ring filter 909 is longitudinally sectioned, the first micro-ring filter 909 includes a silicon substrate 9101, a cover layer 9103, a silicon waveguide ridge region 9104, a first flat plate region 9105 and a second flat plate region 9106, wherein:

[0126] The covering layer 9103 is arranged on the silicon substrate 9101 along the epitaxial growth direction. The silicon substrate 9101 can be made of silicon material, and the covering layer 9103 is made of silicon oxide material. The covering layer 9103 is formed by depositing a silicon dioxide material thin film.

[0127] The silicon waveguide ridge region 9104 is located in the covering layer 9103. The silicon waveguide ridge region 9104 is used to transmit the light beam coupled into the first microring filter 909. Since the silicon waveguide ridge region 9104 absorbs the photon transmission light beam, the optical power of the light beam transmitted by the silicon waveguide ridge region 9104 is relatively high, resulting in a large number of electron-hole pairs in the silicon waveguide ridge region 9104 and the first slab region 9105 and the second slab region 9106 on both sides of the silicon waveguide ridge region 9104.

[0128] The first flat plate region 9105 is located on one side of the silicon waveguide ridge region 9104. One side of the first flat plate region 9105 is connected to one side edge of the silicon waveguide ridge region 9104. An N-type doped region 9107 is provided in the first flat plate region 9105, that is, N-type ions are injected into the first flat plate region 9105 to form an N-type doped region 9107 in the first flat plate region 9105.

[0129] The second flat plate region 9106 is located on the other side of the silicon waveguide ridge region 9104. One side of the second flat plate region 9106 is connected to the edge of the other side of the silicon waveguide ridge region 9104. A P-type doped region 9108 is provided in the second flat plate region 9106. That is, P-type ions are injected into the second flat plate region 9106 to form a P-type doped region 9108 in the second flat plate region 9106. The P-type doped region 9108 and the N-type doped region 9107 can form a PN junction.

[0130] The N-type doped region 9107 in the first flat plate region 9105 and the P-type doped region 9108 in the second flat plate region 9106 form a PN junction, and the PN junction surrounds the silicon waveguide ridge region 9104 and part of the first flat plate region 9105 and part of the second flat plate region 9106 connected to the silicon waveguide ridge region 9104, so that the electric field formed by the PN junction passes through the silicon waveguide ridge region 9104, thereby causing the PN junction to absorb electron-hole pairs in the silicon waveguide ridge region 9104, the first flat plate region 9105 and the second flat plate region 9106.

[0131] In some embodiments, the N-type doped region 9107 and the silicon waveguide ridge region 9104 are directed toward the edge of the first slab region 9105 ( Fig.12 The P-type doped region 9108 and the edge of the silicon waveguide ridge region 9104 toward the second flat plate region 9106 ( Fig.12 There is a second preset distance between the left edge of the silicon waveguide ridge region 9104, and the first preset distance and the second preset distance may be equal, so that the first flat plate region 9105 and the second flat plate region 9106 are symmetrically arranged on both sides of the silicon waveguide ridge region 9104.

[0132] In some embodiments, the first preset distance and the second preset distance range from 500 nm to 1 μm.

[0133] In some embodiments, the first preset distance and the second preset distance are 0.8 μm, so that the electric field formed by the PN junction can quickly absorb the electron-hole pairs generated by the two-photon absorption effect.

[0134] In some embodiments, in order to apply voltage to the PN junction, the first microring filter 909 also includes a contact electrode, through which the PN junction is powered; the contact electrode includes a first contact electrode 9109 and a second contact electrode 9110, the first contact electrode 9109 and the second contact electrode 9110 are located in the covering layer 9103, along the epitaxial growth direction, the first contact electrode 9109 is arranged above the first flat plate region 9105, and the first contact electrode 9109 is close to the N-type doped region 9107, so as to facilitate the power supply to the N-type doped region 9107 through the first contact electrode 9109.

[0135] Along the epitaxial growth direction, the second contact electrode 9110 is disposed above the second flat plate region 9106 , and the second contact electrode 9110 is close to the P-type doping region 9108 , so as to facilitate power supply to the P-type doping region 9108 through the second contact electrode 9110 .

[0136] In some embodiments, the width dimension of the first flat plate region 9105 may be the same as the width dimension of the second flat plate region 9106, the width dimension of the first flat plate region 9105 is larger than the width dimension of the silicon waveguide ridge region 9104, the width dimension of the N-type doped region 9107 is smaller than the width dimension of the first flat plate region 9105, the width dimension of the P-type doped region 9108 is smaller than the width dimension of the second flat plate region 9106, the width dimension of the N-type doped region 9107 is the same as the width dimension of the P-type doped region 9108, the width dimension of the first contact electrode 9109 may be equal to or slightly larger than the width dimension of the N-type doped region 9107, and the width dimension of the second contact electrode 9110 may be equal to or slightly larger than the width dimension of the P-type doped region 9108.

[0137] The first contact electrode 9109 can be electrically connected to the power chip on the circuit board 300 by wire bonding, so that the first contact electrode 9109 is connected to the first voltage; the second contact electrode 9110 can be electrically connected to the power chip on the circuit board 300 by wire bonding, so that the second contact electrode 9110 is connected to the second voltage. The first voltage is greater than the second voltage, that is, the first contact electrode 9109 is connected to a high voltage, and the second contact electrode 9110 is connected to a low voltage, so as to apply a reverse bias to the PN junction. The PN junction generates an electric field under the reverse bias, so that the PN junction can quickly absorb the electron-hole pairs generated by the two-photon absorption effect.

[0138] If a forward bias is applied to the PN junction through the first contact electrode 9109 and the second contact electrode 9110, the electric field formed by the PN junction is strong, which will absorb the photons transmitted in the silicon waveguide ridge region 9104, causing the first microring filter 909 to be unable to output light of a specific wavelength.

[0139] In some embodiments, the first slab region 9105 and the second slab region 9106 are slab waveguides, which can reduce the transmission loss of the waveguide. Since silicon has a large nonlinear optical susceptibility, the high refractive index difference and small cross-sectional size of the silicon waveguide itself may lead to an excessively high power density, causing a strong two-photon absorption effect and a free carrier absorption effect. The first slab region 9105 and the second slab region 9106 are respectively arranged on both sides of the silicon waveguide ridge region 9104, and an N-type doped region 9107 is arranged in the first slab region 9105, and a P-type doped region 9108 is arranged in the second slab region 9106. The P-type doped region 9108 is electrically connected to the N-type doped region 9107 to form a PN junction. A reverse bias is applied to the PN junction to form an electric field, so that the PN junction can absorb free carriers, thereby reducing the lifetime of free carriers in the microring filter, thereby reducing the heat generated by the free carrier absorption effect.

[0140] In some embodiments, the first microring filter 909 also includes a buried layer 9102, which is disposed above the silicon substrate 9101, and a covering layer 9103 is disposed above the buried layer 9102, that is, along the epitaxial growth direction, the silicon substrate 9101, the buried layer 9102 and the covering layer 9103 are disposed in sequence, the thickness dimension of the silicon substrate 9101 may be greater than the thickness dimension of the buried layer 9102, and the thickness dimension of the covering layer 9103 may be greater than the thickness dimension of the silicon substrate 9101.

[0141] If it is directly set on the silicon substrate 9101, the light field generated by the silicon waveguide ridge region 9104 may leak to the silicon substrate 9101, increasing the substrate leakage loss; while a buried layer 9102 is set on the silicon substrate 9101, and the silicon waveguide ridge region 9104 is set above the buried layer 9102. The buried layer 9102 can prevent the light field from leaking to the silicon substrate 9101, reducing the substrate leakage loss and ensuring the output optical power of the first microring filter 909.

[0142] In some embodiments, although the microring filter generates heat due to the two-photon absorption effect and changes the refractive index of the microring filter, the microring filter will only generate the two-photon absorption effect at a higher optical power. Due to the two-photon absorption effect, the optical power of the microring filter will be reduced, which will reduce the number of electron-hole pairs, and the heat generated by the movement of the electron-hole pairs will disappear. Therefore, the heat generated by the microring filter due to the two-photon absorption effect is unstable, and the cavity length of the resonant cavity cannot be stably changed by the heat, resulting in an unstable oscillation phenomenon in the output wavelength of the microring filter. In order to eliminate the wavelength oscillation phenomenon caused by the two-photon absorption effect of the microring filter, the electron-hole pairs need to be absorbed by the PN junction.

[0143] In some embodiments, in order to stably change the cavity length of the resonant cavity, the first microring filter 909 also includes a heater 920. The heater 920 is arranged above the covering layer 9103 along the epitaxial growth direction. The heater 920 can be electrically connected to the power chip on the circuit board 300 through wiring to supply power to generate heat to heat the covering layer 9103, thereby changing the refractive index of the first microring filter 909.

[0144] In some embodiments, the wavelength tuning chip 9031 further includes a plurality of absorbers, which are used to absorb the optical power of useless light beams to avoid reflection and generation of stray light.

[0145] The wavelength tuning chip 9031 includes a first absorber 911, a second absorber 912, a third absorber 913 and a fourth absorber 914, the power divider 908 is connected to the input end of the first straight light waveguide, the first absorber 911 is connected to the output end of the first straight light waveguide, the second absorber 912 is connected to the first output end of the second straight light waveguide, the third absorber 913 is connected to the second output end of the second straight light waveguide, the power divider 908 is connected to the input end of the third straight light waveguide, and the fourth absorber 914 is connected to the output end of the third straight light waveguide.

[0146] The first absorber 911 is used to absorb other light beams in the first straight light waveguide except those passing through the first microring filter 909 and the second microring filter 910. The second absorber 912 and the third absorber 913 are used to absorb other light beams in the second straight light waveguide except those passing through the first microring filter 909 and the second microring filter 910. The fourth absorber 914 is used to absorb other light beams in the third straight light waveguide except those passing through the first microring filter 909 and the second microring filter 910.

[0147] Reference Fig. 9In some embodiments, the wavelength tuning chip 9031 further includes a phase modulator 907, which is located between the input coupler 906 and the power divider 908. One end of the phase modulator 907 is connected to the input coupler 906, and the other end of the phase modulator 907 is connected to the input end of the power divider 908. The phase modulator 907 is used to adjust the wavelength of the light beam supported by the resonant cavity to coordinate with the specific wavelength light beam screened by the first microring filter 909 and the second microring filter 910 to coincide with the light beam in the resonant cavity.

[0148] The phase modulator 907 may be provided with a heater. By changing the heater, the cavity length of the phase modulator 907 is changed, and then the cavity length of the resonant cavity is changed, so that a light beam of a certain wavelength supported by the resonant cavity coincides with the light beam of a specific wavelength screened by the two microring filters.

[0149] In some embodiments, the first microring filter 909, the second microring filter 910 and the phase modulator 907 form a wavelength tunable component, and the first microring filter 909 and the second microring filter 910 can filter out a specific wavelength light beam from a light beam in a wavelength range emitted by the semiconductor gain chip 9032, and this wavelength value is determined by the characteristics of the first microring filter 909 and the second microring filter 910. However, the resonant cavity composed of the semiconductor gain chip 9032 and the silicon photonic chip can select to support multiple light beams of different wavelengths according to its own cavity structure, and the multiple wavelengths of light beams supported by the resonant cavity may not overlap with the light beams filtered out by the two microring filters.

[0150] If the multiple wavelengths of light beams supported by the resonant cavity do not overlap with the specific wavelength light beams screened out by the two microring filters, the cavity length of the phase modulator 907 can be changed by changing the refractive index of the phase modulator 907, thereby changing the cavity length of the resonant cavity, so that a certain wavelength of light beam supported by the resonant cavity overlaps with the specific wavelength light beam, so that the resonant cavity emits a light beam of the specific wavelength.

[0151] Fig.13 FIG. 1 is a light path diagram of a light source assembly in an optical module according to some embodiments of the present disclosure. Fig.13As shown, when the laser assembly 901 is used as a light source, the semiconductor gain chip 9032 emits light of a wavelength range, and the light is injected into the wavelength tuning chip 9031 through the input coupler 906. The input light is split by the power divider 908 and enters the first microring filter 909 and the second microring filter 910. After the split light passes through the first microring filter 909, the wavelength that satisfies FSR1 is selected to pass through the first microring filter 909, and the wavelength period satisfies FSR1; then the screened light passes through the second microring filter 910, and the wavelength that satisfies FSR2 is selected to pass through the second microring filter 910, and the wavelength period satisfies FSR2. Only the wavelength that satisfies both FSR1 and FSR2 will be output by the second microring filter 910. The light beam output by the second microring filter 910 is transmitted to the semiconductor gain chip 9032 via the power divider 908 and the input coupler 906. The light beam is reflected back and forth between the semiconductor gain chip 9032 and the wavelength tuning chip 9031, so as to achieve the stable output of the specific wavelength light beam by the semiconductor gain chip 9032.

[0152] The specific wavelength light beam output by the semiconductor gain chip 9032 is converted into collimated light by the first lens 9033. The collimated light directly passes through the isolator 9034 and enters the second lens 9035. The second lens 9035 converges the collimated light passing through the isolator 9034 to the semiconductor amplifier chip 9036. The semiconductor amplifier chip 9036 amplifies the power of the specific wavelength light beam. The amplified light is converted into collimated light by the third lens 9037. The collimated light is divided into two beams by the beam splitter 9038. One beam is coupled into the internal optical fiber adapter 902 and transmitted to the coherent optical chip 1100 through the internal optical fiber adapter 902; the other beam is injected into the power monitor 9039. The optical power of the specific wavelength light beam is monitored in real time by the power monitor so that the optical power of the specific wavelength light beam is within the preset optical power range.

[0153] The optical module provided by the present invention adopts a silicon filter and a silicon optically adjustable wavelength tuning chip. The silicon filter adopts a microring resonant cavity structure, and forms a PN junction on both sides of the microring waveguide by ion injection. Compared with a microring resonant cavity without an integrated PN junction, applying a reverse bias to the PN junction can quickly absorb electron-hole pairs generated by the nonlinear effect of silicon under high power, thereby eliminating the wavelength oscillation phenomenon caused by the nonlinear effect, and realizing a high-power, narrow-linewidth, and widely adjustable silicon optical integrated laser, which is convenient for application in coherent optical communication, laser radar, sensing and other fields.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. An optical module, characterized in that: include: Circuit boards; A light source, comprising a laser component, the laser component is electrically connected to the circuit board, the laser component comprises a semiconductor gain chip and a wavelength tuning chip, the semiconductor gain chip is used to emit a light beam in a wavelength range, the wavelength tuning chip and the semiconductor gain chip form a resonant cavity; wherein the wavelength tuning chip comprises: An input coupler, used to receive the light beam emitted by the semiconductor gain chip and transmit a light beam of a specific wavelength to the semiconductor gain chip; a power splitter connected to the input coupler, the power splitter being used to split the light beam input by the input coupler; At least one micro-ring filter is connected to the output end of the power divider, and the micro-ring filter is used to filter out a light beam of a specific wavelength from the light beams in the wavelength range; wherein the micro-ring filter comprises: Silicon substrate; A covering layer is arranged on the silicon substrate along the epitaxial growth direction; A silicon waveguide ridge region, located in the cover layer, the silicon waveguide ridge region is used to transmit the light beam and generate electron-hole pairs when transmitting the light beam; A first slab region, located at one side of the silicon waveguide ridge region, wherein an N-type doped region is disposed in the first slab region; A second slab region is located at the other side of the silicon waveguide ridge region, wherein a P-type doping region is provided in the second slab region, wherein the P-type doping region and the N-type doping region form a PN junction, wherein the PN junction is used to absorb electron-hole pairs in the silicon waveguide ridge region, the first slab region and the second slab region; A contact electrode is located in the cover layer, and the contact electrode is electrically connected to the P-type doping region and the N-type doping region to provide a reverse bias voltage to the PN junction.

2. The optical module according to claim 1, characterized in that: At least one microring filter comprises: A first micro-ring filter connected to the first output end of the power divider; A second microring filter is connected to the second output end of the power divider. The second microring filter is connected in series with the first microring filter. The circumference of the second microring filter is different from that of the first microring filter. The second microring filter cooperates with the first microring filter to screen out a light beam of a specific wavelength from the split light.

3. The optical module according to claim 1, characterized in that: The contact electrode includes a first contact electrode and a second contact electrode, the first contact electrode is electrically connected to the N-type doping region, the second contact electrode is electrically connected to the P-type doping region, the first contact electrode is connected to a first voltage, the second contact electrode is connected to a second voltage, and the first voltage is greater than the second voltage to apply a reverse bias to the PN junction.

4. The optical module according to claim 3, characterized in that: Along the epitaxial growth direction, the first contact electrode is disposed on the first flat plate region, and the second contact electrode is disposed on the second flat plate region.

5. The optical module according to claim 1, characterized in that: There is a first preset distance between the N-type doped region and the edge of the silicon waveguide ridge region facing the first flat plate region, and there is a second preset distance between the P-type doped region and the edge of the silicon waveguide ridge region facing the second flat plate region, and the first preset distance is equal to the second preset distance.

6. The optical module according to claim 5, characterized in that: The first preset distance ranges from 500 nm to 1 μm.

7. The optical module according to claim 6, characterized in that: The first preset distance is 0.8 μm.

8. The optical module according to claim 1, characterized in that: The microring filter further comprises a heater, which is arranged on the cover layer along the epitaxial growth direction and is used to heat the silicon waveguide ridge region to change the refractive index of the microring filter.

9. The optical module according to claim 1, characterized in that: The wavelength tuning chip is a silicon photonic chip, and the covering layer is a silicon oxide covering layer.

10. An optical module, characterized in that: include: Circuit boards; A light source, comprising a laser component, the laser component is electrically connected to the circuit board, the laser component comprises a semiconductor gain chip and a wavelength tuning chip, the semiconductor gain chip is used to emit a light beam in a wavelength range, the wavelength tuning chip and the semiconductor gain chip form a resonant cavity; wherein the wavelength tuning chip comprises: An input coupler, used to receive the light beam emitted by the semiconductor gain chip and transmit a light beam of a specific wavelength to the semiconductor gain chip; a power splitter connected to the input coupler, the power splitter being used to split the light beam input by the input coupler; At least one micro-ring filter is connected to the output end of the power divider, and the micro-ring filter is used to filter out a light beam of a specific wavelength from the light beams in the wavelength range; wherein the micro-ring filter comprises: A silicon waveguide ridge region, used for transmitting a light beam and generating electron-hole pairs when transmitting the light beam; A first slab region, located outside the silicon waveguide ridge region, the first slab region surrounds the silicon waveguide ridge region, an N-type doped region is disposed in the first slab region, and the N-type doped region surrounds the silicon waveguide ridge region; A second slab region is located inside the silicon waveguide ridge region, the silicon waveguide ridge region surrounds the second slab region, a P-type doping region is provided in the second slab region, the silicon waveguide ridge region surrounds the P-type doping region, the P-type doping region and the N-type doping region form a PN junction, and the PN junction is used to absorb electron-hole pairs in the silicon waveguide ridge region, the first slab region and the second slab region; A contact electrode is electrically connected to the P-type doping region and the N-type doping region to provide a reverse bias voltage to the PN junction.

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