Multi-rate optical receiver and optical signal detection method thereof

Abstract

The embodiment of the invention provides a multi-rate optical receiver and an optical signal detection method thereof, and belongs to the technical field of photoelectricity. The multi-rate optical receiver comprises an optical chip unit which comprises a first detector used for detecting an optical signal and a second detector used for converting the optical signal into an optical current signal; the bias voltage regulation and control part is connected with the second detector and converts the light current signal output by the second detector into a bias voltage regulation and control signal; and the bias voltage providing part is interconnected with the first detector, provides bias voltage for the first detector according to the bias voltage regulation and control signal output by the bias voltage regulation and control part so as to change the working state of the first detector, converts the light current signal from the first detector into an electric signal, and outputs the electric signal to the output end of the multi-rate optical receiver. According to the multi-rate optical receiver, bias voltage control is carried out on the thin intrinsic layer in the first controller, so that the working bandwidth is flexibly adjusted for detecting and receiving optical signals at different rates.

Description

Technical Field

[0001] The invention belongs to the field of optoelectronic technology, and in particular relates to a multi-rate optical receiver and a method for detecting optical signals thereof. Background Art

[0002] Optical networks have the characteristics of high transmission speed and long transmission distance, and are rapidly developing in the direction of high speed, multi-channel and large capacity. As the single carrier rate gradually increases, the intercommunication and coexistence of optical modules with different rates is an important technical research direction to achieve smooth evolution of optical networks and optimize cost performance.

[0003] For example, in the optical path switches in the data center network, due to the existence of optical modules with different transmission rates (100G / 200G / 400G / 800G, etc.), in order to ensure data transmission speed and transmission quality, it is necessary to achieve arbitrary exchange between multi-rate optical modules. Another example is in the passive optical network where multiple generations coexist, the current PON optical network has evolved to 50G, so the existing GPON, 10G-PON, 50G-PON and other multi-rate optical modules need to be integrated to achieve smooth evolution.

[0004] Therefore, optical modules that can achieve multi-rate signal reception are obviously easier to reduce costs and improve network flexibility. At present, optical modules mainly rely on transimpedance amplifiers (TIAs) for multi-rate signal reception. When receiving low-rate and low-optical-power signals, TIAs increase the transimpedance gain and reduce the receiver's bandwidth. When receiving high-rate and high-optical-power signals, TIAs reduce the transimpedance gain and increase the receiver's bandwidth. In current single-channel optical switching with rates of 10GBd and 50GBd, the use of TIAs can meet multi-rate optical reception. However, when the single-channel rate is further increased to 100GBd or even 200GBd, it is difficult to achieve compatibility between high-speed and low-speed optical detection through TIAs.

[0005] In view of this, a new type of multi-rate optical receiver and optical signal detection method thereof is needed to realize fast conversion detection of optical signals of different rates. Summary of the invention

[0006] In order to solve at least one aspect of the above problems and defects in the prior art, an embodiment of the present invention provides a multi-rate optical receiver and a method for detecting an optical signal thereof, which flexibly adjusts the working bandwidth for detecting and receiving optical signals of different rates by biasing a thin intrinsic layer in a first controller. The technical solution is as follows:

[0007] According to one aspect of the present invention, a multi-rate optical receiver is provided. The multi-rate optical receiver comprises:

[0008] An optical chip unit, comprising a first detector for detecting an optical signal and a second detector for converting the optical signal into a photocurrent signal;

[0009] A bias control unit, connected to the second detector, converting the photocurrent signal output by the second detector into a bias control signal;

[0010] The bias supply unit is interconnected with the first detector. The bias supply unit provides a bias voltage to the first detector according to the bias control signal output by the bias control unit to change the working state of the first detector, and converts the photocurrent signal from the first detector into an electrical signal and outputs it to the output end of the multi-rate optical receiver.

[0011] Furthermore, the first detector includes a thin-layer intrinsic region that switches between low bandwidth and high bandwidth under different bias voltages, and the thickness of the thin-layer intrinsic region is 50-100 nm.

[0012] In some embodiments, the thin-layer intrinsic region of the first detector is located between the optical waveguide layer and the optical absorption layer of the first detector, and the PN junction direction of the first detector is perpendicular to the waveguide direction.

[0013] In some embodiments, the thin-layer intrinsic region of the first detector is located in the optical waveguide layer of the first detector, and the PN junction direction of the first detector is parallel to the waveguide direction.

[0014] In some embodiments, the bias regulation unit includes a current monitoring unit and a micro control unit; one end of the current monitoring unit is connected to the second detector and the other end is connected to the micro control unit, so that the micro control unit can receive the current from the current monitoring unit and convert it into a voltage signal and output a level to the bias providing unit according to the voltage signal.

[0015] In some embodiments, the bias providing unit includes a transimpedance amplifier, which receives a level, identifies the level, and then adjusts the bias voltage output to the first detector to change the working state of the first detector; the transimpedance amplifier receives a photocurrent signal from the first detector after the working state is changed and outputs it to the output end.

[0016] In some embodiments, the bias providing unit includes a boost circuit chip, which receives a level and adjusts the bias voltage output to the first detector after identifying the level to change the working state of the first detector; and a transimpedance amplifier, which receives a photocurrent signal from the first detector after the working state is changed and outputs it to an output end.

[0017] In some embodiments, the first detector is a high-speed photodetector; and the second detector is a monitoring photodetector.

[0018] In some embodiments, the optical chip unit further includes:

[0019] Edge coupler, which couples the optical signal into the single-mode waveguide of the optical chip unit;

[0020] An optical splitter, which divides the optical signal into a first branch, a second branch and a third branch;

[0021] Polarization beam splitter, which separates the two polarization states of the optical signal and couples them into two single-mode waveguides;

[0022] The adjustable optical attenuator can controllably attenuate the optical signal through voltage control;

[0023] Among them, the optical signal in the first branch passes through the first polarization beam splitter and the first adjustable optical attenuator in sequence and is transmitted through the single-mode waveguide to enter the first input end of the first detector; the optical signal in the second branch passes through the second polarization beam splitter and the second adjustable optical attenuator in sequence and is transmitted through the single-mode waveguide to enter the second input end of the first detector; the optical signal in the third branch is transmitted through the single-mode waveguide to enter the input end of the second detector.

[0024] In some embodiments, the optical splitter splits the optical signal in equal proportions; and the polarization beam splitter includes a light polarization rotating beam splitter.

[0025] According to another aspect of the present invention, a method for detecting a multi-rate optical signal is provided. The detection method uses the multi-rate optical receiver described in the above aspect, and the detection method comprises:

[0026] Inputting the optical signal into the optical chip unit, and transmitting the photocurrent signal to the bias control unit through the second detector;

[0027] The bias control unit converts the photocurrent signal output by the second detector into a bias control signal;

[0028] The bias voltage is provided to the first detector according to the bias control signal by the bias supply unit to change the working state of the first detector, and the photocurrent signal from the first detector is converted into an electrical signal and then output to the output end of the multi-rate optical receiver.

[0029] Furthermore, the thin-layer intrinsic region in the first detector is switched between low bandwidth and high bandwidth under different bias voltages.

[0030] Specifically, the bias voltage regulating unit is configured as follows:

[0031] When the input optical signal is at a first rate, the optical power of the optical signal is a first power, the bias voltage of the first detector is increased, and the thin-layer intrinsic region generates optical gain;

[0032] When the input optical signal is at the second rate, the optical power of the optical signal is at the second power, the bias voltage of the first detector is reduced, and the thin-layer intrinsic region does not generate optical gain;

[0033] The first rate is smaller than the second rate, and the first power is smaller than the second power.

[0034] In some embodiments, the step of switching the thin-layer intrinsic region in the first detector between low bandwidth and high bandwidth under different bias voltages comprises:

[0035] The input optical signal is divided into a first branch, a second branch and a third branch after passing through an edge coupler and an optical splitter in sequence, wherein the optical signals of the first branch and the second branch are coupled to the first detector in sequence through a polarization beam splitter and an adjustable optical attenuator, and the optical signal of the third branch is input to the second detector;

[0036] The input optical signal is converted into a photocurrent signal by a second detector and outputted to a current monitoring unit of the bias voltage control unit;

[0037] The micro control unit receives the current from the current monitoring unit through the bias voltage regulation unit and converts the current into a voltage signal and outputs a level to the transimpedance amplifier of the bias voltage providing unit according to the voltage signal;

[0038] After receiving and identifying the level through a transimpedance amplifier, a bias voltage output to the first detector is adjusted to change the working state of the first detector, and a photocurrent signal from the first detector after the working state is changed is received;

[0039] When the input optical signal is at a first rate, the transimpedance amplifier outputs an increased bias voltage, the thin-layer intrinsic region of the first detector generates optical gain, and the first detector reduces its bandwidth;

[0040] When the input optical signal is at the second rate, the transimpedance amplifier outputs a reduced bias voltage, the thin-layer intrinsic region of the first detector does not generate optical gain, and the first detector increases its bandwidth.

[0041] In some embodiments, the step of switching the thin-layer intrinsic region in the first detector between low bandwidth and high bandwidth under different bias voltages comprises:

[0042] The input optical signal is divided into a first branch, a second branch and a third branch after passing through an edge coupler and an optical splitter in sequence, wherein the optical signals of the first branch and the second branch are coupled to the first detector in sequence through a polarization beam splitter and an adjustable optical attenuator, and the optical signal of the third branch is input to the second detector;

[0043] The input optical signal is converted into a photocurrent signal by a second detector and outputted to a current monitoring unit of the bias voltage control unit;

[0044] The micro control unit receives the current from the current monitoring unit through the bias voltage regulation unit and converts it into a voltage signal and outputs a level to the boost circuit chip of the bias voltage providing unit according to the voltage signal;

[0045] After receiving and identifying the level through the boost circuit chip, the bias voltage output to the first detector is adjusted to change the working state of the first detector;

[0046] receiving a photocurrent signal from the first detector after the working state is changed via a transimpedance amplifier of a bias voltage providing unit;

[0047] When the input optical signal is at the first rate, the boost circuit chip outputs a boosted bias voltage, the thin-layer intrinsic region of the first detector generates optical gain, and the first detector reduces its bandwidth;

[0048] When the input optical signal is at the second rate, the boost circuit chip outputs a reduced bias voltage, the thin-layer intrinsic region of the first detector does not generate optical gain, and the first detector increases its bandwidth.

[0049] The present invention also provides a plurality of embodiments according to the following aspects, which are specifically as follows:

[0050] Aspect 1: An optical chip, used for the multi-rate optical receiver described in the above aspects, the optical chip comprising:

[0051] At least one input channel, used to receive at least one optical signal input to the optical chip;

[0052] An edge coupler, coupling one of the at least one optical signal into a single-mode waveguide of the optical chip unit;

[0053] An optical splitter divides the optical signal into a first branch, a second branch and a third branch;

[0054] A polarization beam splitter is used to separate the two polarization states of the optical signal and couple them into two single-mode waveguides;

[0055] The adjustable optical attenuator can control the attenuation of the optical signal through voltage control;

[0056] in,

[0057] The optical signal in the first branch is transmitted through the first polarization beam splitter and the first adjustable optical attenuator in sequence through the single-mode waveguide and enters the first input end of the first detector;

[0058] The optical signal in the second branch is transmitted through the second polarization beam splitter and the second adjustable optical attenuator in sequence through the single-mode waveguide and enters the second input end of the first detector;

[0059] The optical signal in the third branch is transmitted through the single-mode waveguide and enters the input end of the second detector.

[0060] Aspect 2: An optical chip according to Aspect 1, wherein when the number of channels of at least one input channel is greater than 1, a multiplexer is arranged at the front end of the edge coupler along the optical signal transmission path, and the multiplexer is arranged with at least one input end, and each input end of the at least one input end corresponds one-to-one to each input channel of the at least one input channel.

[0061] Aspect 3: A high-speed photodetector is integrated on an optical chip according to any one of Aspects 1-2, the high-speed photodetector comprises a high-speed photodetection chip, the high-speed photodetection chip comprises an optical chip substrate layer, an optical waveguide layer, a thin layer intrinsic region and a light absorption layer in sequence from the chip substrate upward, and a portion of a high-doped region is made in the optical waveguide layer and the light absorption layer respectively to form a PN junction, and the direction of the PN junction is perpendicular to the waveguide direction.

[0062] Aspect 4: A high-speed photodetector is integrated on an optical chip according to any one of Aspects 1-2, the high-speed photodetector comprises a high-speed photodetection chip, and the high-speed photodetection chip comprises, from the chip substrate upward, an optical chip substrate layer, an optical waveguide layer and a light absorption layer in sequence; wherein a thin layer of intrinsic region is formed in the optical waveguide layer and on one side close to the light absorption layer, and a portion of a highly doped region is made in the optical waveguide layer to form a PN junction, and the direction of the PN junction is parallel to the waveguide direction.

[0063] Aspect 5: A multi-channel multi-rate optical receiver, using the optical chip according to any one of aspects 1-2, and integrating the high-speed photodetector according to any one of aspects 3-4 on the optical chip.

[0064] The multi-rate optical receiver and the optical signal detection method thereof provided by the embodiments of the present invention have at least one or part of the following advantages:

[0065] (1) The multi-rate optical receiver and the optical signal detection method provided by the embodiments of the present invention are provided with a bias control unit connected to the output end of the optical chip. Based on the different optical powers of optical signals at different rates, the bias voltage is formed by collecting the photocurrent signal to control the bias of the high-speed photodetector and thus adjust its working bandwidth.

[0066] (2) The multi-rate optical receiver and the optical signal detection method provided by the embodiments of the present invention implement switching of different bandwidths under different bias voltages to flexibly receive optical signals of different rates by inserting a thin layer of intrinsic region between the light absorption layer and the optical waveguide layer of the high-speed photodetector;

[0067] (3) The multi-rate optical receiver and the optical signal detection method provided by the embodiment of the present invention can generate optical gain at a lower voltage and reduce power consumption by setting a thin intrinsic region, which does not require a charge control region compared to a traditional avalanche photodiode;

[0068] (4) The multi-rate optical receiver and the optical signal detection method thereof provided by the embodiments of the present invention set two ways of forming the thin-layer intrinsic region and the directions of forming the two corresponding PN junctions, and can flexibly select different film layer formation processes for manufacturing. In particular, the thin-layer intrinsic region is set in the optical waveguide layer and the PN junction is parallel to the waveguide direction. The thin-layer intrinsic region can be realized by the ion implantation process, and the control of the film thickness is simpler and more accurate.

[0069] (5) The multi-rate optical receiver and the optical signal detection method thereof provided in the embodiments of the present invention set two paths for providing bias voltage. When the performance of the transimpedance amplifier cannot meet the compatibility of multi-rate optical signal detection and reception, the path of the boost circuit chip can be selected to continue to provide the bias voltage. At the same time, the control method of the path of the boost circuit chip is simpler, which further simplifies the calculation and control process, thereby reducing the manufacturing cost.

[0070] (6) The second detector, i.e., the monitoring photodetector, provided in the multi-rate optical receiver and the optical signal detection method thereof provided in the embodiments of the present invention is only used for converting optical signals into electrical signals. Therefore, a larger volume of optical absorption layer can be selected to monitor weak optical signals, thereby further improving the receiving detection sensitivity of multi-rate optical signals.

[0071] (7) The multi-rate optical receiver and optical signal detection method provided by the embodiments of the present invention can use common semiconductor materials and common film formation processes to make high-speed photodetectors. The manufacturing process is simple and does not increase manufacturing costs.

[0072] (8) The multi-rate optical receiver and the optical signal detection method provided by the embodiments of the present invention can be expanded to a multi-channel optical receiver by setting a multiplexer to realize fast conversion detection of multi-channel multi-rate optical signals, with high integration and simple structure.

[0073] (9) The multi-rate optical receiver and the optical signal detection method thereof provided by the embodiments of the present invention can be widely applied to high-speed optical switching and multi-generation coexisting optical access networks to meet the information exchange between optical modules of different rates during optical path switching. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments in conjunction with the accompanying drawings, in which:

[0075] Figure 1 is a schematic structural diagram of a multi-rate optical receiver according to Embodiment 1 of the present invention;

[0076] Figure 2 for Figure 1 A schematic diagram of the structure of an optical chip unit of a multi-rate optical receiver shown;

[0077] Figure 3 is a schematic structural diagram of a multi-rate optical receiver according to Embodiment 2 of the present invention;

[0078] Figure 4 for Figure 1 The control flow chart of the multi-rate optical receiver shown controls the first detector through the bias voltage;

[0079] Figure 5 for Figure 3 The control flow chart of the multi-rate optical receiver shown controls the first detector through the bias voltage;

[0080] Figure 6 This is a schematic diagram of the structure of an optical chip unit of a multi-channel multi-rate optical receiver according to Embodiment 3 of the present invention;

[0081] Figure 7 It is a cross-sectional schematic diagram of a chip structure inside a high-speed photodetector of a multi-rate optical receiver according to Embodiment 4 of the present invention;

[0082] Figure 8 It is a cross-sectional schematic diagram of the chip structure inside the high-speed photodetector of the multi-rate optical receiver according to Example 5 of the present invention. DETAILED DESCRIPTION

[0083] The technical solution of the present invention is further specifically described below by examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0084] In optical network technology, as the rate of a single carrier gradually increases, the interoperability and coexistence of optical modules with different rates is an important technical research direction to achieve smooth evolution of optical networks and optimize cost performance. Therefore, optical modules that can receive signals at multiple rates are obviously easier to reduce costs and improve network flexibility.

[0085] For example, when using a transimpedance amplifier (TIA) in an optical receiver, when receiving a low-rate, low-optical-power signal, the TIA increases the transimpedance gain and reduces the receiver's bandwidth, and when receiving a high-rate, high-optical-power signal, the TIA reduces the transimpedance gain and increases the receiver's bandwidth. Although this traditional transimpedance amplifier and optical receiver can meet the requirements of multi-rate optical reception in the current single-channel rate of 10GBd and 50GBd optical switching, when the single-channel rate is further increased to 100GBd or even 200GBd, it is difficult to achieve compatibility between high-speed and low-speed optical detection through TIA.

[0086] Therefore, the present invention proposes a novel multi-rate optical receiver and an optical signal detection method thereof to achieve fast and sensitive conversion detection of optical signals of different rates, thereby satisfying the information exchange between optical modules of different rates in optical path switching.

[0087] See also Figure 1 , shows the structure of a multi-rate optical receiver 100 of an embodiment of the present invention, the multi-rate optical receiver 100 includes three main functional units, namely, an optical chip unit 10, an optoelectronic signal processing unit and an output terminal 50, wherein the optoelectronic signal processing unit further includes a bias control unit 20, a bias supply unit 30 and a limiting amplifier 40. Specifically, the optical chip unit 10 includes a first detector 15 for detecting an optical signal and a second detector 16 for converting an optical signal into a photocurrent signal. The bias control unit 20 is connected to the second detector 16, and converts the photocurrent signal output by the second detector 16 into a bias control signal. The bias supply unit 30 is interconnected with the first detector 15, and the bias supply unit 30 provides a bias voltage to the first detector 15 according to the bias control signal output by the bias control unit 20 to change the working state of the first detector 15, and converts the photocurrent signal from the first detector 15 into an electrical signal, and finally outputs it to the output terminal 50 of the multi-rate optical receiver 100 via the limiting amplifier 40 to complete the reception of the optical signal.

[0088] In one example, the first detector 15 further includes a thin layer intrinsic region 153 for switching between low bandwidth and high bandwidth under different bias voltages (see the internal chip structure of the first detector 15). Figure 7 and Figure 8 As shown in FIG. 1 , the thin intrinsic region 153 will be described in more detail later. The thickness of the thin intrinsic region 153 is 50 to 100 nm. When the first detector 15 receives the bias voltage output from the bias supply unit 30, the thin intrinsic region 153 adjusts the bandwidth of the optical signal received by the first detector 15 according to different bias voltages.

[0089] In one example, see Figure 2 , shows the structure of the optical chip unit 10. Figure 2As shown, in the optical chip unit 10, the transmission path along the input optical signal includes an edge coupler 11, a beam splitter 12, a polarization beam splitter 13, an adjustable optical attenuator 14, a first controller 15 and a second controller 16 in sequence. The input optical signal first enters the edge coupler 11, and the optical signal is coupled to the single-mode waveguide of the optical chip unit 10 through the edge coupler 11. Then the optical signal is divided into three branches through the beam splitter 12. Two of the branches are used to separate the two polarization states of the optical signal and couple them into two single-mode waveguides and input them into the first detector 15 respectively. The first detector 15 outputs the photocurrent signal of the optical signal under the corresponding working state. The remaining branch directly inputs the optical signal to the second detector 16 through the single-mode waveguide for pre-detecting the rate of the optical signal.

[0090] In one example, specifically, the optical splitter 12 divides the input optical signal into a first branch L1, a second branch L2, and a third branch L3. Among them, the optical signal in the first branch L1 first passes through the first polarization beam splitter 13-1 and then enters the first adjustable optical attenuator 14-1 in the first polarization state, and then the first adjustable optical attenuator 14-1 controllably attenuates the input optical signal through voltage control, and finally enters the first input end of the first detector 15 through single-mode waveguide transmission. Similarly, the optical signal in the second branch L2 first passes through the second polarization beam splitter 13-2 and then enters the second adjustable optical attenuator 14-2 in the second polarization state, and then the second adjustable optical attenuator 14-2 controllably attenuates the input optical signal through voltage control, and finally enters the second input end of the first detector 15 through single-mode waveguide transmission. At this point, the first branch L1 and the second branch L2 complete the two polarization states, are coupled separately into two single-mode waveguides, and are input into the first detector 15. The remaining third branch L3 directly inputs the optical signal to the second detector 16 through the single-mode waveguide.

[0091] In one example, alternatively, when performing splitting, the splitter 12 can use a variety of splitting ratios to split the three branches (the first branch L1, the second branch L2, and the third branch L3). That is to say, the splitter 12 can use non-equal-proportional splitting, partial equal-proportional splitting, or complete equal-proportional splitting. Preferably, complete equal-proportional splitting is used in multiple embodiments of the present invention. Those skilled in the art can configure the splitting ratio accordingly according to the requirements of different branches for parameters such as optical power, the different functions to be achieved by different branches, and the like. This example is only an illustrative example, and those skilled in the art should not understand it as a limitation of the present invention.

[0092] In one example, alternatively, the polarization beam splitter 13 may use a crystal waveguide polarization beam splitter, a nanowire waveguide polarization beam splitter, an optical fiber polarization beam splitter, etc. Preferably, an optical fiber polarization rotation beam splitter is used in various embodiments of the present invention. This example is only an illustrative example, and those skilled in the art should not be understood as a limitation of the present invention.

[0093] In one example, the first detector 15 is a high-speed photodetector. Alternatively, the high-speed photodetector may use, for example, a PIN photodiode, an avalanche photodiode, a unidirectional carrier photodetector, a waveguide photodetector, a traveling wave photodetector, etc. Preferably, a high-speed photodiode (HPD) is used in multiple embodiments of the present invention. Those skilled in the art may make a selection based on the performance and operating characteristics of the optical module in the actual optical network equipment. This example is only an illustrative example, and those skilled in the art should not be construed as a limitation of the present invention.

[0094] In one example, the second detector 16 is a monitoring photodetector. Similar to the first detector 15, alternatively, for example, a high-speed photodetector may be used, such as a PIN photodiode, an avalanche photodiode, a unidirectional carrier photodetector, a waveguide photodetector, a traveling wave photodetector, etc. Preferably, a monitoring photodiode (MPD) is used in multiple embodiments of the present invention. Those skilled in the art may make a selection based on the performance and operating characteristics of the optical module in the actual optical network equipment. This example is only an illustrative example, and those skilled in the art should not be construed as a limitation of the present invention.

[0095] In one example, the second detector 16 is only used in the multi-rate optical receiver 100 to pre-detect the input optical signal and output the photocurrent signal through photoelectric conversion. Therefore, a larger second detector 16 may be selected so that the detection chip inside it can have a larger light absorption layer to improve the monitoring of weak optical signals.

[0096] The multi-rate optical receiver 100 of the present invention controls the bias voltage of the first detector 15 (high-speed photodetector) in the optical chip unit 10 through the bias control unit 20 and the bias supply unit 30 based on the different optical powers of optical signals at different rates. The bias voltage is output from the second detector 16 to the first detector 15 after passing through the bias control unit 20 and the bias supply unit 30, forming a bias control loop, thereby realizing fast, accurate and flexible reception of multi-rate optical signals.

[0097] Furthermore, by adjusting the components of the bias supply unit 30 and the regulation relationship or regulation logic between the bias regulation unit 20 and the bias supply unit 30, two control schemes for using bias voltage to switch the working state of the first detector 15 of the optical chip unit 10 are provided in the following embodiment 1 and embodiment 2 respectively. The components used in the two control schemes, the control logic between the components, and the implementation process of the bias control are specifically described as follows.

[0098] Example 1

[0099] See also Figure 1 , shows one of the control schemes, that is, the bias supply unit 30 includes a transimpedance amplifier 31, and the microcontroller unit 22 (MCU) in the bias control unit 20 outputs a bias control signal to the transimpedance amplifier 31. The transimpedance amplifier 31 receives the bias control signal and outputs a bias voltage to the first controller 15 to switch the bandwidth of the received optical signal. On the other hand, the transimpedance amplifier 31 receives the photocurrent signal output by the first controller 15 after the bandwidth is changed and transmits it to the output end 50 of the multi-rate optical receiver 100 through the limiting amplifier 40.

[0100] In one example, specifically, the bias control unit 20 includes a current monitoring unit 21 and a micro control unit 22. One end of the current monitoring unit 21 is connected to the second detector 16 of the optical chip unit 10, and is used to receive a photocurrent signal obtained by the second detector 16 pre-detecting the optical signal input to the optical chip unit 10, and the other end of the current monitoring unit 21 is connected to the micro control unit 22, and is used to output current to the micro control unit 22. The micro control unit 22 receives the current from the current monitoring unit 21 and converts it into a voltage signal and outputs a level to the bias providing unit 30 according to the voltage signal.

[0101] In one example, further, the microcontroller unit 21 is integrated with a calculator, a memory, a processor, etc. and can issue instructions to its downstream components. For example, when the microcontroller unit 21 receives a current output by a current monitoring unit 21, it first obtains a voltage corresponding to the current through its internal calculation processing and forms a voltage signal, and then processes the voltage or the voltage signal to form a bias control signal, and finally the bias control signal is sent to the bias supply unit 30 in the form of an instruction. Preferably, in order to facilitate the bias supply unit 30 to quickly output the bias voltage after receiving the instruction from the microcontroller unit 21, the bias control signal is output as an instruction in the form of a level.

[0102] In one example, alternatively, the micro control unit 21 can output the instruction to the bias voltage providing unit 30 through a common communication protocol or through circuit control. Preferably, various embodiments of the present invention select to send instructions through a communication protocol, and more preferably, the communication protocol uses an IIC (Inter-Integrated Circuit) communication protocol. This example is only an illustrative example, and those skilled in the art should not be understood as a limitation of the present invention.

[0103] In one example, the bias supply unit 30 includes a transimpedance amplifier 31, and the transimpedance amplifier 31 is provided with two functions. First, one of the functions is that the transimpedance amplifier 31 receives the instruction (i.e., the bias control signal, i.e., the level) issued by the microcontroller unit 21 of the bias control unit 20 and adjusts the bias voltage output to the first detector 15 after identifying the level to change the working state of the first detector 15. After that, another function of the transimpedance amplifier 31 is to receive the photocurrent signal from the first detector 15 after the working state is changed (which is the same optical signal as the optical signal pre-detected by the second detector 16) and continue to output (subsequently output to the output terminal 50 through the limiting amplifier 40).

[0104] In one example, alternatively, the transimpedance amplifier 31 can use an existing model or type of transimpedance amplifier, such as an operational amplifier or an active current-to-voltage converter using a field effect transistor, which can achieve the above two functions. Those skilled in the art can select the model according to the actual situation of the actual optical network system or other optical communication occasions. This example is only an illustrative example, and those skilled in the art should not be understood as a limitation of the present invention.

[0105] In one example, alternatively, the output terminal 50 and the micro control unit 21 in the bias regulation unit 20 can realize information exchange, so as to realize operations such as reading, writing, monitoring, and controlling of the micro control unit 21 by the host computer.

[0106] In one example, specifically, the optical chip unit 10, the bias control unit 20 and the bias supply unit 30 can be configured to sensitively and quickly switch the working state of the first detector 15 to receive optical signals of different rates. Figure 1 and Figure 2 As shown, the specific process of switching the working state of the first detector 15 for optical signals of different rates is described as follows.

[0107] First, in the optical chip unit 10, the input optical signal is divided into a first branch L1, a second branch L2 and a third branch L3 after passing through the edge coupler 11 and the optical splitter 12 in sequence, wherein the optical signals of the first branch L1 and the second branch L2 are coupled to the first detector 15 in sequence through the polarization beam splitter 13 and the adjustable optical attenuator 14, and the optical signal of the third branch L3 is input to the second detector 16. The input optical signal is converted into a photocurrent signal in advance by the second detector 16 and output to the current monitoring unit 21 of the bias control unit 20.

[0108] Afterwards, in the bias control unit 20 , the micro control unit 22 receives the current from the current monitoring unit 21 and converts it into a voltage signal and outputs a level (ie, a bias control signal) to the transimpedance amplifier 31 of the bias providing unit 30 according to the voltage signal.

[0109] Then, in the bias providing unit 30, the level (i.e., the bias control signal) is received and identified by the transimpedance amplifier 31, and the bias voltage output to the first detector 15 is adjusted to change the working state of the first detector 15 (i.e., the first detector 15 is used to receive different bandwidths of optical signals of different rates).

[0110] Finally, after the first detector 15 in the optical chip unit 10 receives the bias voltage outputted by the transimpedance amplifier 31 of the bias voltage providing unit 30, the first detector 15 adjusts the bandwidth of the corresponding optical signal received and forms a photocurrent signal of the optical signal through the thin layer intrinsic region 153 in the first detector 15. After receiving the photocurrent signal, the transimpedance amplifier 31 continues to output it to the limiting amplifier 40 and finally outputs it to the output terminal 50 of the multi-rate optical receiver 100.

[0111] Generally, optical signals of different rates actually correspond to different optical powers of the optical signals. For example, when the rate of an optical signal is relatively low, its optical power is also low, and when the rate of an optical signal is relatively high, its optical power is also high. The reason for the relatively low rate of an optical signal may be that, for example, the transmission equipment, transmission system, optical network, etc. are still in a relatively low configuration stage. Correspondingly, the relatively high rate of an optical signal is usually due to the use of currently more advanced optical network equipment, and the higher-speed optical network that may be realized in the future can bring about higher-speed optical signal transmission, etc. The following is combined with Figure 4 The optical signal transmission flow chart shown illustrates the specific process of switching the working state of the multi-rate optical receiver 100 when the optical signal rates are different.

[0112] In one example, corresponding to the case where the optical signal rate is relatively low, the input optical signal is defined as a first rate (alternatively, the range of the first rate is a single-channel rate less than 10 GBd), that is, the input optical signal is a first rate optical signal, and the optical power of the first rate optical signal is the first power. In order to ensure that the first detector 15 in the optical chip unit 10 can quickly and accurately detect and transmit the first rate optical signal, it is necessary to reduce the bandwidth of the first detector 15 for receiving the optical signal in principle.

[0113] Specifically, using the above-mentioned multi-rate optical receiver 100 , the second detector 16 in the optical chip unit 10 detects the first rate optical signal in advance and converts it into a first rate photocurrent and outputs it to the current monitoring unit 21 of the bias control unit 20 .

[0114] The current monitoring unit 21 transmits the received current to the micro control unit 22. The micro control unit 22 forms a first voltage signal through operation processing and converts the first voltage signal into a first level as a first instruction to send to the transimpedance amplifier 31 in the bias supply unit 30. Corresponding to the first rate of the optical signal, the first instruction is to increase the bias voltage of the first detector 15.

[0115] When the transimpedance amplifier 31 receives the first instruction to increase the bias voltage of the first detector 15 , it adjusts the bias voltage to the first bias voltage and outputs it to the first detector 15 .

[0116] Since the chip of the first detector 15 includes a thin intrinsic region 153 , the thin intrinsic region 153 generates optical gain under the first bias voltage, thereby reducing the bandwidth of the first detector 15 (at this time, the first detector 15 operates under the first bandwidth).

[0117] In this way, the first detector 15 detects and receives the first rate optical signal under the first bandwidth to form a first rate photocurrent signal which is transmitted to the transimpedance amplifier 31, and the transimpedance amplifier 31 continues to transmit the signal through the limiting amplifier 40 and finally transmits the signal to the output end 50 of the multi-rate optical receiver to complete the reception of the first rate optical signal.

[0118] In one example, it corresponds to the case where the optical signal rate is relatively high. It is defined that the input optical signal is a second rate (alternatively, the second rate ranges from a single-channel rate of 50 to 200 GBd, preferably, 100 to 200 GBd), the second rate is greater than the aforementioned first rate, and the input optical signal is a second rate optical signal, then the optical power of the second rate optical signal is a second power, and the second power is greater than the aforementioned first power. In order to ensure that the first detector 15 in the optical chip unit 10 can quickly and accurately detect and transmit the second rate optical signal, it is necessary to increase the bandwidth of the first detector 15 for receiving the optical signal in principle.

[0119] Specifically, using the multi-rate optical receiver 100 described above, the second detector 16 in the optical chip unit 10 detects the second rate optical signal in advance and converts it into a second rate optical current and outputs it to the current monitoring unit 21 of the bias control unit 20 .

[0120] The current monitoring unit 21 transmits the received current to the micro control unit 22. The micro control unit 22 forms a second voltage signal through operation processing and converts the second voltage signal into a second level as a second instruction to send to the transimpedance amplifier 31 in the bias supply unit 30. Corresponding to the second rate of the optical signal, the second instruction is to reduce the bias voltage of the first detector 15.

[0121] When the transimpedance amplifier 31 receives the second instruction to reduce the bias voltage of the first detector 15 , it adjusts the bias voltage to the second bias voltage and outputs the second bias voltage to the first detector 15 .

[0122] Since the chip of the first detector 15 includes a thin intrinsic region 153 , the thin intrinsic region 153 generates optical gain under the second bias voltage, thereby reducing the bandwidth of the second detector 15 (at this time, the first detector 15 operates under the second bandwidth).

[0123] In this way, the first detector 15 detects and receives the second rate optical signal under the second bandwidth to form a second rate photocurrent signal which is transmitted to the transimpedance amplifier 31, and the transimpedance amplifier 31 continues to transmit the signal through the limiting amplifier 40 and finally transmits the signal to the output end 50 of the multi-rate optical receiver to complete the reception of the second rate optical signal.

[0124] Example 2

[0125] See also Figure 3 , another control scheme is shown, that is, the bias supply unit 30' includes a transimpedance amplifier 31 and a boost circuit chip 32, and the microcontroller unit 22 (MCU) in the bias control unit 20 outputs a bias control signal to the boost circuit chip 32. The boost circuit chip 32 receives the bias control signal and outputs a bias voltage to the first controller 15 to switch the bandwidth of the received optical signal. The transimpedance amplifier 31 receives the photocurrent signal output by the first controller 15 after the bandwidth is changed, and transmits it to the output end 50 of the multi-rate optical receiver 100' through the limiting amplifier 40.

[0126] In one example, preferably, in the above two control schemes, the structure of the optical chip unit 10 remains unchanged, that is, using Figure 2The optical chip unit 10 shown. At the same time, other functional units, such as the components used in the bias control unit 20, the limiting amplifier 40 and the component selection, position layout and control logic of the output end 50 also remain unchanged. The connection between the bias control unit 20 and the second detector 16 in the optical chip unit 10 and the transmission of the current signal also remain unchanged. The function of the transimpedance amplifier 31 of the bias providing unit 30' to receive the optical signal output from the first controller 15 and continue to transmit it remains unchanged, but it no longer receives the bias control signal from the bias control unit 20. Instead, a boost circuit chip 32 is used to receive the bias control signal.

[0127] In one example, specifically, the optical chip unit 10, the bias control unit 20 and the bias supply unit 30' (including the transimpedance amplifier 31 and the boost circuit chip 32) can also be configured to sensitively and quickly switch the working state of the first detector 15 to receive optical signals of different rates. Figure 2 and Figure 3 As shown, the specific process of switching the working state of the first detector 15 for optical signals of different rates is described as follows.

[0128] First, in the optical chip unit 10, the transmission process of the input optical signal and the process of outputting the photocurrent signal through the first detector 15 and the second detector 16 are the same as those of the previous control scheme, and will not be repeated here.

[0129] Afterwards, in the bias control unit 20, the micro control unit 22 receives the current from the current monitoring unit 21 and converts it into a voltage signal and outputs a level (ie, bias control signal) to the boost circuit chip 32 of the bias providing unit 30' according to the voltage signal.

[0130] Then, in the bias providing unit 30', the boost circuit chip 32 receives and identifies the level (i.e., the bias control signal) and adjusts the bias voltage output to the first detector 15 to change the working state of the first detector 15 (i.e., the first detector 15 is used to receive different bandwidths of optical signals of different rates).

[0131] Finally, after the first detector 15 in the optical chip unit 10 receives the bias voltage outputted by the boost circuit chip 32 of the bias supply unit 30', the first detector 15 adjusts the bandwidth of the corresponding optical signal received and forms a photocurrent signal of the optical signal through the thin layer intrinsic region 153 in the first detector 15. After receiving the photocurrent signal, the transimpedance amplifier 31 continues to output it to the limiting amplifier 40 and finally outputs it to the output terminal 50 of the multi-rate optical receiver 100' to complete the reception of optical signals of different rates.

[0132] See also Figure 5, shows the workflow of using the bias supply unit 30' of embodiment 2, especially the boost circuit chip 32, to detect and receive the conversion of optical signals of different rates. Figure 4 The working principle of the workflow of the embodiment 1 shown is the same, so the same aspects of the workflow will not be repeated, and only the differences will be described below.

[0133] After the current monitoring unit 21 of the bias control unit 20 transmits the received current to the micro control unit 22, the micro control unit 22 forms a first voltage signal (or a second voltage signal) through calculation processing and converts the first voltage signal (or the second voltage signal) into a first level (or a second level) as a first instruction (or a second instruction) and sends it to the boost circuit chip 32 in the bias supply unit 30'. Corresponding to the first rate (or the second rate) of the optical signal, the first instruction (or the second instruction) is to increase (or decrease) the bias voltage of the first detector 15.

[0134] When the boost circuit chip 32 receives the first instruction (or second instruction) to increase (or decrease) the bias voltage of the first detector 15, it adjusts the bias voltage to the first bias voltage (or second bias voltage) and outputs it to the first detector 15. The first detector 15 reduces (or increases) the operating bandwidth to the first operating bandwidth (or second operating bandwidth) through the thin intrinsic region 153 in the chip.

[0135] In this way, the first rate (or second rate) optical signal detected and received by the first detector 15 under the first bandwidth (or second bandwidth) and the first rate (or second rate) photocurrent signal formed are still transmitted to the transimpedance amplifier 31, and are further transmitted by the transimpedance amplifier 31 through the limiting amplifier 40 and finally transmitted to the output end 50 of the multi-rate optical receiver 100' to complete the reception of the first rate (or second rate) optical signal.

[0136] Example 3

[0137] In an example, the above-mentioned Embodiment 1 and Embodiment 2 illustrate the structure, control logic and conversion, reception and detection process of optical signals of different rates of the multi-rate optical receiver 100 and the multi-rate optical receiver 100' of the present invention by taking the application on a single-channel optical receiver as an example. Then, on the basis of the above-mentioned Embodiment 1 and Embodiment 2, the single channel can also be expanded to multiple channels, so as to obtain a multi-channel multi-rate optical receiver. The multi-channel multi-rate optical receiver can be applied to the optical path switch OCS scenario. For example, the use of CWDM4 optical module can make the multi-rate optical receiver 100 and the multi-rate optical receiver 100' of the present invention expandable to four channels.

[0138] In one example, see Figure 6, shows an optical chip unit 10 ′ expanded to receive multi-rate optical signals through multiple channels. Specifically, at least one input channel is provided in the optical chip unit 10 ′, and the input channel is used to receive at least one optical signal input to the optical chip unit 10 .

[0139] In one example, further, for example Figure 6 Schematically shows optical signal 1, optical signal 2...optical signal N, at this time, the number of input channels required by the optical chip unit 10' is greater than 1. Therefore, in order to selectively control only one optical signal to enter the optical chip unit 10' at a time, a multiplexer (MUX) 17 is set at the front end of the edge coupler 11 along the optical signal transmission path. The multiplexer 17 is provided with at least one input end, and each input end of the at least one input end corresponds to each input channel of the at least one input channel. That is to say, for example, the input end R of the multiplexer 17 1 Corresponding to the input channel of the received optical signal 1, the input terminal R 2 Corresponding to the input channel of the received optical signal 2, and so on, the input port R N Corresponding to the input channel for receiving the optical signal N. Meanwhile, other components and optical signal transmission paths in the optical chip unit 10' remain unchanged.

[0140] In one example, further, the transimpedance amplifier 31 in the bias supply unit 30 of the multi-rate optical receiver 100 or the boost circuit chip 32 in the bias supply unit 30' of the multi-rate optical receiver 100' is correspondingly configured to include at least one control channel interconnected with the first controller 15 to achieve conversion of multi-channel multi-rate optical signals. The specific conversion process is described in Embodiment 1 and Embodiment 2, and the only difference is the switching between the channels, which will not be repeated here.

[0141] According to another aspect of the present invention, a high-speed photodetector 15 is provided, in which a high-speed photodetection chip is integrated. The high-speed photodetector 15 is integrated in the optical chip unit 10 of the multi-rate optical receiver 100, the multi-rate optical receiver 100' and the optical chip unit 10' of the multi-channel multi-rate optical receiver described in the above aspects and the above embodiments.

[0142] See also Figure 7 and Figure 8 , respectively show the structures of two high-speed photodetection chips in the high-speed photodetector 15. The following is a detailed description through Example 4 and Example 5 respectively.

[0143] Example 4

[0144] In one example, if Figure 7As shown, the high-speed photodetection chip in the high-speed photodetector 15 includes an optical chip substrate layer 151, an optical waveguide layer 152, a thin layer intrinsic region 153 and a light absorption layer 154 from the chip substrate upward, and a portion of high-doped regions 155a and 155b are respectively made in the optical waveguide layer 152 and the light absorption layer 154 to form a PN junction. At this time, the direction of the PN junction is perpendicular to the waveguide direction.

[0145] In one example, alternatively, in order to allow the thin intrinsic region 153 to flexibly adjust the working bandwidth of the high-speed photodetector 15 (first controller 15) through a bias voltage, the thin intrinsic region 153 has a preset thickness. Preferably, the preset thickness ranges from 50 to 100 nm.

[0146] In one example, alternatively, the material used to generate the thin layer intrinsic region 153 and the light absorbing layer 154 may use common semiconductor materials. Preferably, Ge, GeS i or InGaAs may be used. Alternatively, the thin layer intrinsic region 153 may be formed on the optical waveguide layer 152 by an epitaxial growth process.

[0147] In one example, the provision of the thin intrinsic region 153 changes the optical gain establishment time of the high-speed photodetector 15 (the optical gain establishment time refers to the total time required for the optical gain).

[0148] When the thickness of the thin layer intrinsic region 153 is set at 50-100nm, if the bias voltage received by the high-speed photodetector 15 is less than 3.3V, then the electric field of the thin layer intrinsic region 153 is less than the critical electric field strength of avalanche breakdown of the layer of material, so that the high-speed photodetector 15 is in a high-bandwidth (for example, the second bandwidth in Example 1-2) working state to realize the detection of high-speed optical signals (for example, the second-rate optical signals in Example 1-2).

[0149] On the contrary, if the bias voltage received by the high-speed photodetector 15 is greater than or equal to 3.3V, the electric field of the thin-layer intrinsic region 153 is greater than the critical electric field strength of the avalanche breakdown of the layer of material, and optical gain will be generated in the thin-layer intrinsic region 153. Limited by the optical gain establishment time, the high-speed photodetector 15 will be in a low-bandwidth (such as the first bandwidth in Example 1-2) working state to achieve the detection of low-rate optical signals (such as the first-rate optical signals in Example 1-2). At the same time, since the optical gain will increase the photocurrent, the detection sensitivity of the high-speed photodetector 15 to the low-rate optical signal will be increased.

[0150] In one example, compared with a conventional high-speed photodetector (such as a conventional avalanche photodiode), the high-speed photodetector 15 does not require a charge control region due to the setting of the thin-layer intrinsic region 153 and can generate optical gain at a lower voltage, such as no more than 6 to 7V.

[0151] Example 5

[0152] In one example, if Figure 8 As shown, the high-speed photodetection chip in the high-speed photodetector 15 includes an optical chip substrate layer 151, an optical waveguide layer 152, and an optical absorption layer 154 from the chip substrate upward, wherein a thin layer intrinsic region 153 is formed in the optical waveguide layer 152 and on one side close to the optical absorption layer 154, and a part of the high-doped regions 155a and 155b are made in the optical waveguide layer 152 to form a PN junction. At this time, the direction of the PN junction is parallel to the waveguide direction.

[0153] In one example, since the thin intrinsic region 153 is formed inside the optical waveguide layer 152, an ion implantation process may be used to form the thin intrinsic region 153. Compared with the epitaxial growth process in Embodiment 4, the ion implantation process is easier to control the thickness of the thin intrinsic region 153.

[0154] The other structures and settings of the high-speed photodetector 15 and its working process in Example 5 are the same as those in Example 4 and will not be described again here.

[0155] According to another aspect of the present invention, a method for detecting a multi-rate optical signal is provided, which uses the multi-rate optical receiver 100, multi-rate optical receiver 100', multi-channel multi-rate optical receiver described in the above aspects and embodiments, and the optical chip and high-speed photodetector 15 used therein.

[0156] Combination Figure 1-Figure 8 And Embodiment 1 to Embodiment 5, taking the multi-rate optical receiver 100 as an example, the detection method includes:

[0157] The optical signal is input to the optical chip unit 10, and the photocurrent signal is transmitted to the bias control unit 20 through the second detector 16;

[0158] The photocurrent signal output by the second detector 16 is converted into a bias control signal by the bias control unit 20;

[0159] The bias supply unit 30 provides a bias voltage to the first detector 15 according to the bias control signal to change the working state of the first detector, and converts the photocurrent signal from the first detector 15 into an electrical signal and outputs it to the output terminal 50 of the multi-rate optical receiver 100 .

[0160] In one example, further, the thin-layer intrinsic region 153 in the first detector 15 is switched between low bandwidth and high bandwidth under different bias voltages.

[0161] In one example, specifically, in conjunction with Figure 1 and Figure 4 In the multi-rate optical receiver 100 shown, the bias control signal output by the bias control unit 20 is received by the transimpedance amplifier 31 of the bias supply unit 30 and forms a corresponding bias voltage, which is then output to the first detector 15 of the optical chip unit 10. For a more specific control process, please refer to the description in Example 1, which will not be repeated here.

[0162] In one example, specifically, in conjunction with Figure 3 and Figure 5 In the multi-rate optical receiver 100' shown, the bias control signal output by the bias control unit 20 is received by the boost circuit chip 32 of the bias supply unit 30' and forms a corresponding bias voltage, which is then output to the first detector 15 of the optical chip unit 10. For a more specific control process, please refer to the description in Example 2, which will not be repeated here.

[0163] The multi-rate optical receiver and the optical signal detection method thereof provided by the embodiments of the present invention have at least one or part of the following advantages:

[0164] (1) The multi-rate optical receiver and the optical signal detection method provided by the embodiments of the present invention are provided with a bias control unit connected to the output end of the optical chip. Based on the different optical powers of optical signals at different rates, the bias voltage is formed by collecting the photocurrent signal to control the bias of the high-speed photodetector and thus adjust its working bandwidth.

[0165] (2) The multi-rate optical receiver and the optical signal detection method provided by the embodiments of the present invention implement switching of different bandwidths under different bias voltages to flexibly receive optical signals of different rates by inserting a thin layer of intrinsic region between the light absorption layer and the optical waveguide layer of the high-speed photodetector;

[0166] (3) The multi-rate optical receiver and the optical signal detection method provided by the embodiment of the present invention can generate optical gain at a lower voltage and reduce power consumption by setting a thin intrinsic region, which does not require a charge control region compared to a traditional avalanche photodiode;

[0167] (4) The multi-rate optical receiver and the optical signal detection method thereof provided by the embodiments of the present invention set two ways of forming the thin-layer intrinsic region and the directions of forming the two corresponding PN junctions, and can flexibly select different film layer formation processes for manufacturing. In particular, the thin-layer intrinsic region is set in the optical waveguide layer and the PN junction is parallel to the waveguide direction. The thin-layer intrinsic region can be realized by the ion implantation process, and the control of the film thickness is simpler and more accurate.

[0168] (5) The multi-rate optical receiver and the optical signal detection method thereof provided in the embodiments of the present invention set two paths for providing bias voltage. When the performance of the transimpedance amplifier cannot meet the compatibility of multi-rate optical signal detection and reception, the path of the boost circuit chip can be selected to continue to provide the bias voltage. At the same time, the control method of the path of the boost circuit chip is simpler, which further simplifies the calculation and control process, thereby reducing the manufacturing cost.

[0169] (6) The second detector, i.e., the monitoring photodetector, provided in the multi-rate optical receiver and the optical signal detection method thereof provided in the embodiments of the present invention is only used for converting optical signals into electrical signals. Therefore, a larger volume of optical absorption layer can be selected to monitor weak optical signals, thereby further improving the receiving detection sensitivity of multi-rate optical signals.

[0170] (7) The multi-rate optical receiver and optical signal detection method provided by the embodiments of the present invention can use common semiconductor materials and common film formation processes to make high-speed photodetectors. The manufacturing process is simple and does not increase manufacturing costs.

[0171] (8) The multi-rate optical receiver and the optical signal detection method provided by the embodiments of the present invention can be expanded to a multi-channel optical receiver by setting a multiplexer to realize fast conversion detection of multi-channel multi-rate optical signals, with high integration and simple structure.

[0172] (9) The multi-rate optical receiver and the optical signal detection method thereof provided by the embodiments of the present invention can be widely applied to high-speed optical switching and multi-generation coexisting optical access networks to meet the information exchange between optical modules of different rates during optical path switching.

[0173] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A multi-rate optical receiver, characterized in that: The multi-rate optical receiver comprises: An optical chip unit, comprising a first detector for detecting an optical signal and a second detector for converting the optical signal into a photocurrent signal; a bias control unit, the bias control unit being connected to the second detector and converting the photocurrent signal output by the second detector into a bias control signal; A bias supply unit, wherein the bias supply unit is interconnected with the first detector, and the bias supply unit provides a bias voltage to the first detector according to a bias control signal output by the bias control unit to change the working state of the first detector, and converts the photocurrent signal from the first detector into an electrical signal and outputs it to the output end of the multi-rate optical receiver.

2. The multi-rate optical receiver according to claim 1, characterized in that: The first detector comprises a thin-layer intrinsic region which switches between low bandwidth and high bandwidth under different bias voltages, and the thickness of the thin-layer intrinsic region is 50-100 nm.

3. The multi-rate optical receiver according to claim 2, characterized in that: The thin-layer intrinsic region of the first detector is located between the optical waveguide layer and the light absorption layer of the first detector, and the PN junction direction of the first detector is perpendicular to the waveguide direction.

4. The multi-rate optical receiver according to claim 2, characterized in that: The thin-layer intrinsic region of the first detector is located in the optical waveguide layer of the first detector, and the PN junction direction of the first detector is parallel to the waveguide direction.

5. The multi-rate optical receiver according to any one of claims 1 to 4, characterized in that: The bias voltage regulating unit includes a current monitoring unit and a micro control unit; One end of the current monitoring unit is connected to the second detector and the other end is connected to the micro control unit, so that the micro control unit can receive the current from the current monitoring unit and convert it into a voltage signal and output a level to the bias providing unit according to the voltage signal.

6. The multi-rate optical receiver according to claim 5, characterized in that: The bias voltage providing unit includes a transimpedance amplifier, and the transimpedance amplifier receives the level and adjusts the bias voltage output to the first detector after identifying the level to change the working state of the first detector; The transimpedance amplifier receives the photocurrent signal from the first detector after the working state is changed and outputs it to the output end.

7. The multi-rate optical receiver according to claim 5, characterized in that: The bias voltage providing unit comprises: a boost circuit chip, wherein the boost circuit chip receives the level and recognizes the level, and then adjusts a bias voltage output to the first detector to change a working state of the first detector; A transimpedance amplifier receives the photocurrent signal from the first detector after the working state is changed and outputs it to the output end.

8. The multi-rate optical receiver according to claim 5, characterized in that: The first detector is a high-speed photodetector; The second detector is a monitoring photodetector.

9. The multi-rate optical receiver according to any one of claims 1 to 4, characterized in that: The optical chip unit also includes: An edge coupler, wherein the edge coupler couples the optical signal into the single-mode waveguide of the optical chip unit; An optical splitter, wherein the optical splitter divides the optical signal into a first branch, a second branch, and a third branch; A polarization beam splitter, which couples two polarization states of an optical signal into two single-mode waveguides separately; An adjustable optical attenuator, wherein the adjustable optical attenuator can controllably attenuate an optical signal through voltage control; in, The optical signal in the first branch is transmitted through the first polarization beam splitter and the first adjustable optical attenuator in sequence through the single-mode waveguide and enters the first input end of the first detector; The optical signal in the second branch is transmitted through the second polarization beam splitter and the second adjustable optical attenuator in sequence through the single-mode waveguide and enters the second input end of the first detector; The optical signal in the third branch is transmitted through a single-mode waveguide and enters the input end of the second detector.

10. The multi-rate optical receiver according to claim 9, characterized in that: The optical splitter performs equal-proportional optical splitting on the optical signal; The polarization beam splitter includes a light polarization rotating beam splitter.

11. A method for detecting a multi-rate optical signal, characterized in that: The detection method uses a multi-rate optical receiver according to any one of claims 1 to 10, and the detection method comprises: Inputting the optical signal into the optical chip unit, and transmitting the photocurrent signal to the bias control unit through the second detector; The bias control unit converts the photocurrent signal output by the second detector into a bias control signal; The bias voltage providing unit provides a bias voltage to the first detector according to the bias control signal to change the working state of the first detector, and converts the photocurrent signal from the first detector into an electrical signal and outputs it to the output end of the multi-rate optical receiver.

12. The detection method according to claim 11, characterized in that: The thin intrinsic region in the first detector is switched between low bandwidth and high bandwidth under different bias voltages.

13. The detection method according to claim 12, characterized in that: The bias voltage regulating unit is configured as follows: When the input optical signal is at a first rate, the optical power of the optical signal is a first power, the bias voltage of the first detector is increased, and the thin-layer intrinsic region generates optical gain; When the input optical signal is at the second rate, the optical power of the optical signal is at the second power, the bias voltage of the first detector is reduced, and the thin-layer intrinsic region does not generate optical gain; The first rate is smaller than the second rate, and the first power is smaller than the second power.

14. The detection method according to claim 12, characterized in that: The step of switching the thin-layer intrinsic region in the first detector between low bandwidth and high bandwidth under different bias voltages comprises: The input optical signal is divided into a first branch, a second branch and a third branch after passing through an edge coupler and an optical splitter in sequence, wherein the optical signals of the first branch and the second branch are coupled to the first detector in sequence through a polarization beam splitter and an adjustable optical attenuator, and the optical signal of the third branch is input to the second detector; The input optical signal is converted into a photocurrent signal by a second detector and outputted to a current monitoring unit of the bias voltage control unit; The micro control unit receives the current from the current monitoring unit through the bias voltage regulation unit and converts the current into a voltage signal and outputs a level to the transimpedance amplifier of the bias voltage providing unit according to the voltage signal; After receiving and identifying the level through a transimpedance amplifier, a bias voltage output to the first detector is adjusted to change the working state of the first detector, and a photocurrent signal from the first detector after the working state is changed; When the input optical signal is at a first rate, the transimpedance amplifier outputs an increased bias voltage, the thin-layer intrinsic region of the first detector generates optical gain, and the first detector reduces its bandwidth; When the input optical signal is at the second rate, the transimpedance amplifier outputs a reduced bias voltage, the thin-layer intrinsic region of the first detector does not generate optical gain, and the first detector increases its bandwidth.

15. The detection method according to claim 12, characterized in that: The step of switching the thin-layer intrinsic region in the first detector between low bandwidth and high bandwidth under different bias voltages comprises: The input optical signal is divided into a first branch, a second branch and a third branch after passing through an edge coupler and an optical splitter in sequence, wherein the optical signals of the first branch and the second branch are coupled to the first detector in sequence through a polarization beam splitter and an adjustable optical attenuator, and the optical signal of the third branch is input to the second detector; The input optical signal is converted into a photocurrent signal by a second detector and outputted to a current monitoring unit of the bias voltage control unit; The micro control unit receives the current from the current monitoring unit through the bias voltage regulation unit and converts it into a voltage signal and outputs a level to the boost circuit chip of the bias voltage providing unit according to the voltage signal; After receiving and identifying the level through a boost circuit chip, a bias voltage output to the first detector is adjusted to change the working state of the first detector; receiving a photocurrent signal from the first detector after the working state is changed via a transimpedance amplifier of a bias voltage providing unit; When the input optical signal is at the first rate, the boost circuit chip outputs a boosted bias voltage, the thin-layer intrinsic region of the first detector generates optical gain, and the first detector reduces its bandwidth; When the input optical signal is at the second rate, the boost circuit chip outputs a reduced bias voltage, the thin-layer intrinsic region of the first detector does not generate optical gain, and the first detector increases its bandwidth.

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