A low-temperature wavelength control circuit and optical module

Abstract

The invention discloses a low-temperature wavelength control circuit and an optical module, wherein the low-temperature wavelength control circuit comprises an electrical interface unit, an MCU circuit, a DML driving circuit, a DCDC circuit and an emission component; the DCDC circuit is respectively connected to the MCU circuit and the emission component; the DML driving circuit is respectively connected to the MCU circuit and the emission component; the electrical interface unit is respectively connected to the DML driving circuit, the MCU circuit, and the circuit between the DML driving circuit and the MCU circuit; the low-temperature wavelength control circuit and the optical module provided by the invention output a corresponding voltage to the emission component by adopting an adjustable DCDC circuit, can drive a heating resistor in the emission component to perform corresponding temperature compensation, the power conversion efficiency is above 90%, can effectively reduce the power dissipation of the driving circuit, and at the same time, the circuit stability is better, the wavelength control accuracy is higher, and the low-temperature wavelength control circuit and the optical module provided by the invention have a high value for popularization and application.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to a low-temperature wavelength control circuit and an optical module. Background Art

[0002] Compared with DWDM (Dense Wavelength Division Multiplexing) system, CWDM (Coarse wavelength division multiplexing) system has a wider wavelength interval, and the industry's standard wavelength interval is 20nm. For the working center wavelength of the optical module, the wavelength offset within the working temperature range is within ±6.5nm, and the wavelength of the common DFB (Distributed Feedback Laser) laser has a temperature offset of 0.09 to 0.1nm / ℃. Due to the technical bottleneck of InP (Indium Phosphide) laser, the wavelength requirements for commercial-grade environment applications can be met, but when used in industrial environments, because the low-temperature wavelength will exceed the ±6.5nm range, it is necessary to add a laser heating function.

[0003] At present, there are two common solutions. One is to use TEC (Thermal Electronic Cooler) to control the wavelength, but the circuit is relatively complex, the laser packaging process is complicated, and the cost is more than twice the original. It is difficult to use in batches in cost-sensitive applications; the other is to use a heating resistor. Although this solution is low-cost and easy to implement, the common use of MOS tubes or triodes as current amplification drive circuits has the following defects:

[0004] (1) The amplification drive circuit composed of MOS tubes or triodes is essentially an LDO power supply design with a conversion efficiency of only 20% to 60%. The conversion efficiency is low and there is a large power dissipation.

[0005] (2) Since the internal reference voltage of the MCU is 2.4V, the DAC can only output 2.4V at most. The common simple driving circuit design is that one end of the transistor or MOS tube is connected to Vcc and the other end is connected to the heating resistor. Here, the turn-on voltage of some MOS tubes or transistors is too low, resulting in the inability to shut down the driving circuit. The heating function keeps working, which will seriously affect the reliability of the product;

[0006] (3) When using DAC to directly drive MOS tubes or transistors, there is no reference voltage, and the circuit stability deviation is prone to critical conduction oscillation problems, causing power supply voltage fluctuations, which may cause abnormal conditions such as MCU reset.

[0007] Therefore, how to improve the existing low-temperature wavelength control scheme to overcome the above-mentioned defects, or to provide a new low-temperature wavelength control technology to increase its applicability, has become one of the important research topics for technicians in this field.

[0008] The above information is provided as background information only to assist with understanding the present disclosure. No determination or admission is made as to whether any of the above may be used as prior art with respect to the present disclosure. Summary of the invention

[0009] The present invention provides a low-temperature wavelength control circuit and an optical module to solve the deficiencies of the prior art.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] In a first aspect, an embodiment of the present invention provides a low-temperature wavelength control circuit, including an electrical interface unit, an MCU circuit, a DML driving circuit, a DCDC circuit and a transmitting component; wherein,

[0012] The DCDC circuit is connected to the MCU circuit and the transmitting component respectively;

[0013] The DML driving circuit is connected to the MCU circuit and the transmitting component respectively;

[0014] The electrical interface unit is respectively connected to the DML driving circuit, the MCU circuit, and the circuit between the DML driving circuit and the MCU circuit;

[0015] The electrical interface unit is used to receive an input electrical signal;

[0016] The DML driving circuit is used to adjust the bias current and modulation current under the control of the MCU circuit, and drive the transmitting component;

[0017] The transmitting component is used to receive the electrical signal from the electrical interface unit, and convert the electrical signal into an optical signal output according to the driving of the bias current and the modulation current;

[0018] The DCDC circuit is used to adjust the voltage output to the transmitting component under the control of the MCU circuit to control the power consumption of the resistor inside the transmitting component to achieve the purpose of heating the temperature of the laser.

[0019] Further, in the low-temperature wavelength control circuit, the transmitting component includes a laser diode, a photodetection diode and a heating resistor;

[0020] The positive electrode and the negative electrode of the laser diode are both connected to the DML driving circuit;

[0021] The cathode of the photodetection diode is connected to the DML driving circuit, and the anode of the photodetection diode is grounded;

[0022] One end of the heating resistor is connected to the DCDC circuit, and the other end of the heating resistor is grounded.

[0023] Further, in the low-temperature wavelength control circuit, the TD+ pin of the electrical interface unit is connected to the TDIP pin of the DML driving circuit;

[0024] The TD- pin of the electrical interface unit is connected to the TDIN pin of the DML driving circuit;

[0025] The VCCT pin of the electrical interface unit is respectively connected to the VCC33 pin of the DML driving circuit, the SCL_M pin of the MCU circuit, the SDA_M pin of the MCU circuit, and the VIN pin of the DCDC circuit;

[0026] The TX_Disable pin of the electrical interface unit is respectively connected to the TX_DIS pin of the MCU circuit and the TXDIS pin of the DML driving circuit;

[0027] The SDA pin of the electrical interface unit is connected to the SDA pin of the MCU circuit;

[0028] The SCL pin of the electrical interface unit is connected to the SCL pin of the MCU circuit.

[0029] Further, in the low-temperature wavelength control circuit, the SCL pin of the DML driving circuit is connected to the SCL_M pin of the MCU circuit;

[0030] The SDA pin of the DML driving circuit is connected to the SDA_M pin of the MCU circuit;

[0031] The LI pin of the DML driving circuit is connected to the LO pin of the DML driving circuit through a first inductor;

[0032] The PMSVCC pin of the DML driving circuit is grounded through a first capacitor;

[0033] The SVCC pin of the DML driving circuit is connected between the PMSVCC pin of the DML driving circuit and the first capacitor;

[0034] The OUTK pin of the DML driving circuit is connected to the cathode of the laser diode;

[0035] The OUTA pin of the DML driving circuit is connected to the positive electrode of the laser diode;

[0036] The VCCTA pin of the DML driving circuit is connected between the OUTA pin of the DML driving circuit and the positive electrode of the laser diode through an anti-interference device;

[0037] The VCCTK pin of the DML driving circuit is connected between the VCCTA pin of the DML driving circuit and the anti-interference device through a second capacitor;

[0038] The MDIN pin of the DML driving circuit is connected to the cathode of the photodetection diode.

[0039] Further, in the low-temperature wavelength control circuit, the EN pin of the MCU circuit is connected to the EN pin of the DCDC circuit;

[0040] The Temp_DAC pin of the MCU circuit is connected to the FB pin of the DCDC circuit through a first resistor.

[0041] Further, in the low-temperature wavelength control circuit, the LX pin of the DCDC circuit is connected to the heating resistor via a second inductor;

[0042] The GND pin of the DCDC circuit is grounded;

[0043] The FPWM pin of the DCDC circuit is connected between the VIN pin of the DCDC circuit and the VCCT pin of the electrical interface unit.

[0044] Further, the low temperature wavelength control circuit also includes a second resistor, a third resistor, a fourth resistor, a third capacitor and a fourth capacitor;

[0045] One end of the second resistor is connected between the FB pin of the DCDC circuit and the first resistor, and the other end of the second resistor is grounded;

[0046] One end of the third resistor is connected between the FB pin of the DCDC circuit and the first resistor, and the other end of the third resistor is connected between the LX pin of the DCDC circuit and the heating resistor;

[0047] One end of the fourth resistor is connected between the EN pin of the DCDC circuit and the EN pin of the MCU circuit, and the other end of the fourth resistor is grounded;

[0048] One end of the third capacitor is connected between the VIN pin of the DCDC circuit and the VCCT pin of the electrical interface unit, and the other end of the third capacitor is grounded;

[0049] One end of the fourth capacitor is connected between the LX pin of the DCDC circuit and the heating resistor, and the other end of the fourth capacitor is grounded.

[0050] Further, the low temperature wavelength control circuit also includes a fifth resistor and a sixth resistor;

[0051] The fifth resistor is connected in series between the VCCT pin of the electrical interface unit and the SDA_M pin of the MCU circuit;

[0052] The sixth resistor is connected in series between the VCCT pin of the electrical interface unit and the SCL_M pin of the MCU circuit.

[0053] Furthermore, in the low-temperature wavelength control circuit, the anti-interference device is a ferrite bead.

[0054] In a second aspect, an embodiment of the present invention provides an optical module, comprising the low-temperature wavelength control circuit as described in the first aspect above.

[0055] A low-temperature wavelength control circuit and an optical module provided in an embodiment of the present invention can drive a heating resistor in the transmitting component to perform corresponding temperature compensation by adopting an adjustable DCDC circuit to output a corresponding voltage to the transmitting component. The power conversion efficiency is above 90%, which can effectively reduce the power dissipation of the driving circuit. At the same time, the circuit has better stability and higher wavelength control accuracy, and has a high value for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0057] Figure 1 It is a functional module schematic diagram of a low-temperature wavelength control circuit provided by an embodiment of the present invention;

[0058] Figure 2 It is a schematic diagram of the circuit principle of a low-temperature wavelength control circuit provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0059] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] In the description of the present invention, it is to be understood that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally disposed component. When a component is considered to be "disposed on" another component, it may be directly disposed on the other component or there may be a centrally disposed component.

[0061] In addition, terms such as "long", "short", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific direction or operate with a specific direction structure, and should not be understood as a limitation of the present invention.

[0062] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0063] Embodiment 1

[0064] In view of the defects of the existing laser heating technology, the inventor, based on his rich practical experience and professional knowledge in designing and manufacturing such products for many years, and in conjunction with the application of theory, actively conducts research and innovation, in order to create a solution that can solve the problem of low-temperature wavelength drift of optical modules, so that the produced optical modules are more reliable. After continuous research and design, and repeated trial production and improvement, the present invention with real practical value was finally created.

[0065] Please refer to Figures 1-2 , an embodiment of the present invention provides a low-temperature wavelength control circuit including an electrical interface unit J1, an MCU circuit U2, a DML driving circuit U1, a DCDC circuit U3 and a transmitting component J2; wherein,

[0066] The DCDC circuit U3 is connected to the MCU circuit U2 and the transmitting component J2 respectively;

[0067] The DML driving circuit U1 is connected to the MCU circuit U2 and the transmitting component J2 respectively;

[0068] The electrical interface unit J1 is respectively connected to the DML driving circuit U1, the MCU circuit U2, and the circuit between the DML driving circuit U1 and the MCU circuit U2;

[0069] The electrical interface unit J1 is used to receive input electrical signals;

[0070] The DML driving circuit U1 is used to adjust the bias current and modulation current under the control of the MCU circuit U2, and drive the transmitting component J2;

[0071] The transmitting component J2 is used to receive the electrical signal from the electrical interface unit J1, and convert the electrical signal into an optical signal output according to the driving of the bias current and the modulation current;

[0072] The DCDC circuit U3 is used to adjust the voltage output to the transmitting component J2 under the control of the MCU circuit U2, so as to control the power consumption of the internal resistance of the transmitting component J2, so as to achieve the purpose of heating the temperature of the laser.

[0073] It should be noted that the MCU circuit U2 reads the information of the electrical interface unit J1 through the Slave IIC (S_IIC), and uses the Master IIC (M_IIC) to configure and read the registers of the DML driving circuit U1; the internal CDR of the DML driving circuit U1 is powered by 1.8V, and the use of the DCDC circuit U3 can effectively reduce the overall power consumption of the chip and ensure high-speed signal transmission.

[0074] In addition, the high-speed differential line output driver adopts DC coupling, which saves more power than AC coupling. The LD positive voltage of the transmitting component J2 (laser) is provided by the internal DCDC Buck-Boost conversion circuit output of the DML drive circuit U1 to provide bias current and forward voltage, and the LD positive voltage is automatically adjusted to keep the LD negative terminal voltage constant.

[0075] In this embodiment, the transmitting component J2 includes a laser diode LD, a photodetection diode PD and a heating resistor Rt;

[0076] The positive electrode (LD+) and the negative electrode (LD-) of the laser diode LD are both connected to the DML driving circuit U1;

[0077] The cathode (PD-) of the photodetection diode PD is connected to the DML driving circuit U1, and the anode (PD+) of the photodetection diode PD is grounded;

[0078] One end of the heating resistor Rt is connected to the DCDC circuit U3 , and the other end of the heating resistor Rt is grounded.

[0079] In this embodiment, the TD+ pin of the electrical interface unit J1 is connected to the TDIP pin of the DML driving circuit U1;

[0080] The TD- pin of the electrical interface unit J1 is connected to the TDIN pin of the DML driving circuit U1;

[0081] The VCCT pin of the electrical interface unit J1 is respectively connected to the VCC33 pin of the DML driving circuit U1, the SCL_M pin of the MCU circuit U2, the SDA_M pin of the MCU circuit U2, and the VIN pin of the DCDC circuit U3;

[0082] The TX_Disable pin of the electrical interface unit J1 is connected to the TX_DIS pin of the MCU circuit U2 and the TXDIS pin of the DML driving circuit U1 respectively;

[0083] The SDA pin of the electrical interface unit J1 is connected to the SDA pin of the MCU circuit U2;

[0084] The SCL pin of the electrical interface unit J1 is connected to the SCL pin of the MCU circuit U2.

[0085] In this embodiment, the SCL pin of the DML driving circuit U1 is connected to the SCL_M pin of the MCU circuit U2;

[0086] The SDA pin of the DML driving circuit U1 is connected to the SDA_M pin of the MCU circuit U2;

[0087] The LI pin of the DML driving circuit U1 is connected to the LO pin of the DML driving circuit U1 through the first inductor L1;

[0088] The PMSVCC pin of the DML driving circuit U1 is grounded via a first capacitor C1;

[0089] The SVCC pin of the DML driving circuit U1 is connected between the PMSVCC pin of the DML driving circuit U1 and the first capacitor C1;

[0090] The OUTK pin of the DML driving circuit U1 is connected to the cathode (LD-) of the laser diode LD;

[0091] The OUTA pin of the DML driving circuit U1 is connected to the positive electrode (LD+) of the laser diode LD;

[0092] The VCCTA pin of the DML driving circuit U1 is connected between the OUTA pin of the DML driving circuit U1 and the positive electrode (LD+) of the laser diode LD through an anti-interference device;

[0093] The VCCTK pin of the DML driving circuit U1 is connected between the VCCTA pin of the DML driving circuit U1 and the anti-interference device through a second capacitor C2;

[0094] The MDIN pin of the DML driving circuit U1 is connected to the cathode (PD-) of the photodetection diode PD.

[0095] It should be noted that the first inductor L1 and the first capacitor C1 are necessary components of the internal DCDCBuck-Boost conversion circuit of the DML driving circuit U1. Specifically, the first inductor L1 is an energy storage inductor, and the first capacitor C1 is a decoupling filter capacitor.

[0096] The anti-interference device is a bias current filter network, which also isolates high-frequency signal transmission. The second capacitor C2 provides impedance matching for the internal differential drive output circuit. The MDIN pin of the DML drive circuit U1 provides a forward bias for the PD of the transmitting component J2.

[0097] Preferably, the anti-interference component is a ferrite bead FB1.

[0098] In this embodiment, the EN pin of the MCU circuit U2 is connected to the EN pin of the DCDC circuit U3;

[0099] The Temp_DAC pin of the MCU circuit U2 is connected to the FB pin of the DCDC circuit U3 through a first resistor R1.

[0100] In this embodiment, the LX pin of the DCDC circuit U3 is connected to the heating resistor Rt through the second inductor L2;

[0101] The GND pin of the DCDC circuit U3 is grounded;

[0102] The FPWM pin of the DCDC circuit U3 is connected between the VIN pin of the DCDC circuit U3 and the VCCT pin of the electrical interface unit J1 .

[0103] Preferably, the low temperature wavelength control circuit further includes a second resistor R2, a third resistor R3, a fourth resistor R4, a third capacitor C3 and a fourth capacitor C4;

[0104] One end of the second resistor R2 is connected between the FB pin of the DCDC circuit U3 and the first resistor R1, and the other end of the second resistor R2 is grounded;

[0105] One end of the third resistor R3 is connected between the FB pin of the DCDC circuit U3 and the first resistor R1, and the other end of the third resistor R3 is connected between the LX pin of the DCDC circuit U3 and the heating resistor Rt;

[0106] One end of the fourth resistor R4 is connected between the EN pin of the DCDC circuit U3 and the EN pin of the MCU circuit U2, and the other end of the fourth resistor R4 is grounded;

[0107] One end of the third capacitor C3 is connected between the VIN pin of the DCDC circuit U3 and the VCCT pin of the electrical interface unit J1, and the other end of the third capacitor C3 is grounded;

[0108] One end of the fourth capacitor C4 is connected between the LX pin of the DCDC circuit U3 and the heating resistor Rt, and the other end of the fourth capacitor C4 is grounded.

[0109] Preferably, the low temperature wavelength control circuit further includes a fifth resistor R5 and a sixth resistor R6;

[0110] The fifth resistor R5 is connected in series between the VCCT pin of the electrical interface unit J1 and the SDA_M pin of the MCU circuit U2;

[0111] The sixth resistor R6 is connected in series between the VCCT pin of the electrical interface unit J1 and the SCL_M pin of the MCU circuit U2.

[0112] It should be noted that in the design of the DCDC circuit, the enable pin and the voltage regulation function pin are separated, and the circuit stability is better due to the internal reference voltage. The MCU circuit U2 controls the enable output of the DCDC circuit through the IO port (EN pin), and the fourth resistor R4 enables the DCDC circuit to always be in the off state during the power-on and initialization process of the MCU circuit U2; the third capacitor C3 and the fourth capacitor C4 are the necessary filter capacitors of the DCDC circuit U3, the second inductor L2 is the energy storage inductor, and the voltage negative feedback pin (FB pin) of the DCDC circuit U3 samples the resistance voltage of the first resistor R1, the second resistor R2, and the third resistor R3, and compares it with the internal reference voltage Vref to dynamically adjust the PWM duty cycle and change the amount of voltage reduction; when the duty cycle is smaller, the voltage drops lower, and the output minimum voltage is close to the internal reference voltage (Vmin=Vref). When the duty cycle is 1, the output maximum voltage is close to the input power supply voltage (Vmax=Vin).

[0113] The output voltage calculation formula is as follows: (FB pin is high impedance input)

[0114]

[0115] It can be seen from the above formula that when the VDAC of the MCU circuit U2 is 0V, the output voltage of the DCDC circuit U3 is the minimum, and when the VDAC of the MCU is 2.4V, the output voltage of the DCDC circuit U3 is the maximum.

[0116] In the internal design of the transmitting component J2, the heating resistor is a thin film resistor, and the patch position on the tube holder is as close to the LD position as possible to achieve a better heating effect. One end of the functional connection is connected to the tube holder, and the other end is led out to the tube holder PIN pin.

[0117] The present invention adopts a switch-type DCDC voltage-stabilized power supply design to replace the LDO linear voltage-stabilized power supply. The internal MOS tube only works in the switch state, which avoids the triode or MOS tube working in the amplification area and generating large power consumption. The power conversion efficiency is above 90%, which can effectively reduce the power dissipation of the driving circuit.

[0118] Since the adjustable DCDC circuit U3 is selected to drive the heating resistor Rt, the dynamic range of the output voltage is Vref≤Vout≤Vcc, so temperature compensation can be performed according to the deviation of the low-temperature wavelength, thereby dynamically saving power consumption.

[0119] The DAC output voltage of the MCU circuit U2 is fed back and compared with the Vref reference voltage of the internal operational amplifier to adjust the duty cycle through a resistor voltage divider. It does not simply use the DAC to directly drive the conduction degree of the amplifier tube. There will be no critical conduction oscillation problem, and the circuit operation is more stable.

[0120] Although the terms such as electrical interface unit, MCU circuit, DML driving circuit, DCDC circuit and transmitting component are used more frequently in this article, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

[0121] A low-temperature wavelength control circuit provided by an embodiment of the present invention can drive the heating resistor in the transmitting component to perform corresponding temperature compensation by adopting an adjustable DCDC circuit to output a corresponding voltage to the transmitting component. The power conversion efficiency is above 90%, which can effectively reduce the power dissipation of the driving circuit. At the same time, the circuit has better stability and higher wavelength control accuracy, and has a high value for promotion and application.

[0122] Embodiment 2

[0123] A second embodiment of the present invention provides an optical module, comprising the low-temperature wavelength control circuit as described in the first embodiment.

[0124] An optical module provided by an embodiment of the present invention includes all embodiments of the low-temperature wavelength control circuit, and thus has all the beneficial effects of the low-temperature wavelength control circuit, which will not be described in detail here.

[0125] Thus far, the description of the above-described embodiments is provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a specific embodiment are generally not subject to the limitations of the specific embodiment, but when applicable, they can be interchanged and used for selected embodiments even if not specifically shown or described. In many respects, the same element or feature also can be changed. This variation is not considered to be a departure from the present disclosure, and all such modifications are intended to be included in the scope of the present disclosure.

[0126] Example embodiments are provided so that the present disclosure will be thorough and the scope will be fully conveyed to those skilled in the art. In order to thoroughly understand the embodiments of the present disclosure, numerous details are set forth, such as examples of specific parts, devices, and methods. Obviously, for those skilled in the art, it is not necessary to use specific details, the example embodiments can be implemented in many different forms, and neither should be construed as limiting the scope of the present disclosure. In certain example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0127] Here, specialized vocabulary is used only for the purpose of describing specific example embodiments, and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a" and "the" used herein may be intended to include plural forms as well. The terms "including" and "having" are inclusive, and therefore specify the presence of the claimed features, wholes, steps, operations, elements and / or components, but do not exclude the presence or additional presence of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof. Unless the order of execution is clearly indicated, the method steps, processing and operations described herein are not interpreted as necessarily needing to be performed in the specific order discussed and shown. It should also be understood that additional or optional steps may be adopted.

[0128] When an element or layer is referred to as being "on ...", "engaged with ...", "connected to" or "coupled to" another element or layer, it may be directly on another element or layer, engaged with another element or layer, connected to or coupled to another element or layer, or there may be an intervening element or layer. In contrast, when an element or layer is referred to as being "directly on ...", "directly engaged with ...", "directly connected to" or "directly coupled to" another element or layer, there may be no intervening element or layer. Other words used to describe element relationships should be interpreted in a similar manner (e.g., "between ..." and "directly between ...", "adjacent" and "directly adjacent", etc.). The term "and / or" used herein includes any and all combinations of one or more of the associated listed items. Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts are not limited by these terms. These terms may only be used to distinguish one element, component, region or part from another element, component, region or part. Unless clearly indicated by the context, the use of terms such as "first", "second" and other numerical terms herein does not imply sequence or order. Therefore, the first element, component, region, layer or part discussed below can adopt the terminology of the second element, component, region, layer or part without departing from the teaching of the exemplary embodiment.

[0129] Spatially relative terms, such as "inside", "outside", "below", "below...", "lower", "above", "upper", etc., may be used herein for ease of description to describe the relationship between one element or feature and one or more other elements or features as shown in the figure. Spatially relative terms may be meant to include different orientations of the device in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, the elements described as "below other elements or features" or "below elements or features" will be oriented as "above other elements or features". Therefore, the example term "below..." may include both upward and downward orientations. The device can be oriented in other ways (rotated 90 degrees or other orientations) and interpreted with the spatially relative descriptions herein.

Claims

1. A low temperature wavelength control circuit, characterized in that: It includes an electrical interface unit, an MCU circuit, a DML driving circuit, a DCDC circuit and a transmitting component; wherein, The DCDC circuit is connected to the MCU circuit and the transmitting component respectively; The DML driving circuit is connected to the MCU circuit and the transmitting component respectively; The electrical interface unit is respectively connected to the DML driving circuit, the MCU circuit, and the circuit between the DML driving circuit and the MCU circuit; The electrical interface unit is used to receive an input electrical signal; The DML driving circuit is used to adjust the bias current and modulation current under the control of the MCU circuit, and drive the transmitting component; The transmitting component is used to receive the electrical signal from the electrical interface unit, and convert the electrical signal into an optical signal output according to the driving of the bias current and the modulation current; The DCDC circuit is used to adjust the voltage output to the transmitting component under the control of the MCU circuit to control the power consumption of the resistor inside the transmitting component to achieve the purpose of heating the temperature of the laser.

2. The low temperature wavelength control circuit according to claim 1, characterized in that: The transmitting assembly includes a laser diode, a photodetection diode and a heating resistor; The positive electrode and the negative electrode of the laser diode are both connected to the DML driving circuit; The cathode of the photodetection diode is connected to the DML driving circuit, and the anode of the photodetection diode is grounded; One end of the heating resistor is connected to the DCDC circuit, and the other end of the heating resistor is grounded.

3. The low temperature wavelength control circuit according to claim 2, characterized in that: The TD+ pin of the electrical interface unit is connected to the TDIP pin of the DML driving circuit; The TD- pin of the electrical interface unit is connected to the TDIN pin of the DML driving circuit; The VCCT pin of the electrical interface unit is respectively connected to the VCC33 pin of the DML driving circuit, the SCL_M pin of the MCU circuit, the SDA_M pin of the MCU circuit, and the VIN pin of the DCDC circuit; The TX_Disable pin of the electrical interface unit is respectively connected to the TX_DIS pin of the MCU circuit and the TXDIS pin of the DML driving circuit; The SDA pin of the electrical interface unit is connected to the SDA pin of the MCU circuit; The SCL pin of the electrical interface unit is connected to the SCL pin of the MCU circuit.

4. The low temperature wavelength control circuit according to claim 3, characterized in that: The SCL pin of the DML driving circuit is connected to the SCL_M pin of the MCU circuit; The SDA pin of the DML driving circuit is connected to the SDA_M pin of the MCU circuit; The LI pin of the DML driving circuit is connected to the LO pin of the DML driving circuit through a first inductor; The PMSVCC pin of the DML driving circuit is grounded through a first capacitor; The SVCC pin of the DML driving circuit is connected between the PMSVCC pin of the DML driving circuit and the first capacitor; The OUTK pin of the DML driving circuit is connected to the cathode of the laser diode; The OUTA pin of the DML driving circuit is connected to the positive electrode of the laser diode; The VCCTA pin of the DML driving circuit is connected between the OUTA pin of the DML driving circuit and the positive electrode of the laser diode through an anti-interference device; The VCCTK pin of the DML driving circuit is connected between the VCCTA pin of the DML driving circuit and the anti-interference device through a second capacitor; The MDIN pin of the DML driving circuit is connected to the cathode of the photodetection diode.

5. The low temperature wavelength control circuit according to claim 4, characterized in that: The EN pin of the MCU circuit is connected to the EN pin of the DCDC circuit; The Temp_DAC pin of the MCU circuit is connected to the FB pin of the DCDC circuit through a first resistor.

6. The low-temperature wavelength control circuit according to claim 5, characterized in that: The LX pin of the DCDC circuit is connected to the heating resistor via a second inductor; The GND pin of the DCDC circuit is grounded; The FPWM pin of the DCDC circuit is connected between the VIN pin of the DCDC circuit and the VCCT pin of the electrical interface unit.

7. The low-temperature wavelength control circuit according to claim 6, characterized in that: Also includes a second resistor, a third resistor, a fourth resistor, a third capacitor and a fourth capacitor; One end of the second resistor is connected between the FB pin of the DCDC circuit and the first resistor, and the other end of the second resistor is grounded; One end of the third resistor is connected between the FB pin of the DCDC circuit and the first resistor, and the other end of the third resistor is connected between the LX pin of the DCDC circuit and the heating resistor; One end of the fourth resistor is connected between the EN pin of the DCDC circuit and the EN pin of the MCU circuit, and the other end of the fourth resistor is grounded; One end of the third capacitor is connected between the VIN pin of the DCDC circuit and the VCCT pin of the electrical interface unit, and the other end of the third capacitor is grounded; One end of the fourth capacitor is connected between the LX pin of the DCDC circuit and the heating resistor, and the other end of the fourth capacitor is grounded.

8. The low temperature wavelength control circuit according to claim 3, characterized in that: Also including a fifth resistor and a sixth resistor; The fifth resistor is connected in series between the VCCT pin of the electrical interface unit and the SDA_M pin of the MCU circuit; The sixth resistor is connected in series between the VCCT pin of the electrical interface unit and the SCL_M pin of the MCU circuit.

9. The low-temperature wavelength control circuit according to claim 4, characterized in that: The anti-interference device is a ferrite bead.

10. An optical module, characterized in that: The method comprises the low-temperature wavelength control circuit as claimed in any one of claims 1 to 9.

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