Low-noise amplifier for front end of microwave optical receiver

Abstract

The utility model discloses a low noise amplifier used at the front end of a microwave optical receiver, which is connected with the microwave optical receiver through a coupling module, and the microwave optical receiver receives a microwave optical signal and converts the microwave optical signal into an electric signal. And the coupled signal is input into the low-noise amplification module to be amplified, so that the problem that the bandwidth and the gain of the existing low-noise amplifier cannot meet the requirements of a microwave optical receiver is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of optical fiber communication, in particular to a low-noise amplifier used for the front end of a microwave optical receiver. Background Art

[0002] In the optical fiber communication system, the task of the optical receiver is to restore the information carried by the optical carrier after the optical fiber transmission with the minimum additional noise and distortion. Therefore, the output characteristics of the optical receiver comprehensively reflect the performance of the entire optical fiber communication system. After the optical signal emitted by the optical transmitter is transmitted, not only the amplitude is attenuated, but also the pulse waveform is broadened. The role of the optical receiver is to detect the weak optical signal transmitted, and amplify, shape, and regenerate the original transmission signal.

[0003] Low noise amplifiers mainly realize small signal low noise amplification and reduce the noise coefficient of receivers or transmitters. They are an indispensable part of the wireless receiving front end, which directly affects the sensitivity and dynamic range of the system. Low noise amplifiers are mainly used in the front end of optical receivers. The frequency range, performance indicators, packaging form and power supply method can be customized.

[0004] For a microwave optical receiver, its bandwidth depends on a low noise amplifier, so a high-bandwidth, high-gain low noise amplifier that can be used in the front end of a microwave optical receiver is needed. Utility Model Content

[0005] In view of the problems raised by the above background technology, the purpose of the utility model is to provide a low-noise amplifier for the front end of a microwave optical receiver, which is connected to the microwave optical receiver through a coupling module, and the microwave optical receiver receives the microwave optical signal and converts it into an electrical signal, and then couples the electrical signal and inputs the coupled signal into a low-noise amplifier module for amplification, thereby solving the problem that the bandwidth and gain of the existing low-noise amplifier cannot meet the requirements for use in microwave optical receivers.

[0006] The utility model is realized by the following technical solutions:

[0007] A low noise amplifier for a front end of a microwave optical receiver, comprising:

[0008] A low noise amplifier module connected to the microwave optical receiver via a coupling module;

[0009] A linearization module, the linearization module is used to adjust the linearity of the low noise amplifier module;

[0010] The low noise amplification module includes an input matching network, a first amplification circuit, an inter-stage matching network, a second amplification circuit and an output matching network which are connected in sequence.

[0011] In the above technical solution, the low-noise amplifier module amplifies the signal through the first amplifier circuit and the second amplifier circuit, thereby meeting the high gain requirement; the low-noise amplifier module can effectively expand the matching bandwidth through the input matching network, the inter-stage matching network and the output matching network, thereby meeting the high bandwidth requirement of the microwave optical receiver.

[0012] Since the low-noise amplifier module sacrifices a part of its linearity when improving its efficiency, in order to balance the linearity and amplification efficiency, the utility model adjusts the linearity of the low-noise amplifier module through a linearization module, thereby maintaining a certain linearity balance while meeting high gain and high bandwidth.

[0013] In an optional embodiment, the coupling module includes a capacitor C1, a capacitor C2 and a resistor R1;

[0014] Among them, one end of the resistor R1 is connected to the microwave optical receiver, and the other end is connected to the positive electrode of the power supply; one end of the capacitor C1 is connected to the middle node between the resistor R1 and the power supply, and the other end is grounded; one end of the capacitor C2 is connected to the middle node between the resistor R1 and the microwave optical receiver, and the other end is connected to the input port of the low-noise amplifier module;

[0015] The input matching network includes: an inductor L1, an inductor L2 and a capacitor C3;

[0016] Among them, one end of the inductor L1 is connected to the first node, and the other end is grounded; one end of the inductor L2 is connected to the first node; one end of the capacitor C3 is connected to the first node, and the other end is grounded; the first node is connected to the capacitor C2.

[0017] In an optional embodiment, the first amplifying circuit includes: a capacitor C4, an inductor L3, a transistor Q1, a resistor R2 and a capacitor C5;

[0018] The capacitor C4 is connected to the gate of the transistor Q1; one end of the inductor L3 is connected to the middle node between the capacitor C4 and the gate of the transistor Q1, and the other end is grounded; the resistor R2 is connected to the source of the transistor Q1 in parallel with the capacitor C5.

[0019] In an optional embodiment, the inter-stage matching network includes: a capacitor C6, and an inductor L4, a resistor R3 and a capacitor C7 connected in series in sequence;

[0020] The capacitor C6 is connected to the drain of the transistor Q1 ; the inductor L4 is connected to an intermediate node between the capacitor C6 and the drain of the transistor Q1 .

[0021] In an optional embodiment, the second amplifier circuit includes: an inductor L5, a transistor Q2, a resistor R5 and a capacitor C9;

[0022] One end of the inductor L5 is connected to the capacitor C6 , and the other end is connected to the gate of the transistor Q2 ; the resistor R5 is connected to the capacitor C9 in parallel and then connected to the source of the transistor Q2 .

[0023] In an optional embodiment, the second amplifying circuit further includes a resistor R4, and the resistor R4 is connected to an intermediate node between the capacitor C6 and the inductor L5.

[0024] In an optional embodiment, the output matching network includes: inductor L6, inductor L7, inductor L8, capacitor C8, capacitor C10, capacitor C11 and resistor R6;

[0025] Among them, the inductor L6 is connected in series with the capacitor C8, and the inductor L6 is connected to the drain of the transistor Q2; the inductor L8 and the capacitor C11 are connected in parallel to the middle node between the inductor L6 and the capacitor C8; the capacitor C10, the inductor L7 and the resistor R6 are connected in series in sequence, the capacitor C10 is connected to the middle node between the capacitor C6 and the inductor L5, and the resistor R6 is connected between the inductor L6 and the capacitor C11.

[0026] In an optional embodiment, the linearization module includes: a transistor Q3, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C16, a resistor R7, a resistor R8, an inductor L9 and an inductor L10;

[0027] Among them, the capacitor C12 is connected to the base of the transistor Q3, the inductor L9 is connected to the emitter of the transistor Q3, the capacitor C13 and the capacitor C14 are connected in parallel at both ends of the inductor L9, and the resistor R7 is connected in parallel with the capacitor C14; the capacitor C15 is connected in parallel with the inductor L10, one end of which is connected to the emitter of the transistor Q3, and the other end is connected to one end of the capacitor C16, and the other end of the capacitor C16 is connected to the resistor R8.

[0028] In an optional embodiment, the transistor Q3 is GaAs HBT.

[0029] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0030] The utility model is connected with a microwave optical receiver through a coupling module, the microwave optical receiver receives the microwave optical signal and converts it into an electrical signal, then couples the electrical signal and inputs the coupled signal into a low-noise amplifier module for amplification, thereby solving the problem that the bandwidth and gain of the existing low-noise amplifier cannot meet the requirements for use in the microwave optical receiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the embodiments of the present utility model, constitute a part of this application, and do not constitute a limitation of the embodiments of the present utility model. In the drawings:

[0032] Figure 1 A schematic diagram of the structure of a low noise amplifier provided in Example 1 of the utility model;

[0033] Figure 2 A schematic diagram of the structure of a linearization module provided in Example 1 of the utility model;

[0034] Figure 3 This is a schematic diagram of the structure of a low noise amplifier used in the front end of a microwave optical receiver provided in Example 1 of the utility model. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the utility model more clearly understood, the utility model is described in detail in an optional embodiment in combination with the embodiments and drawings below. The schematic implementation mode of the utility model and its description are only used to explain the utility model and are not intended to limit the utility model.

[0036] Example 1

[0037] Figure 1 The schematic diagram of the structure of the low noise amplifier provided in Example 1 of the utility model is as follows: Figure 1 As shown, a low noise amplifier for a front end of a microwave optical receiver comprises:

[0038] A low noise amplifier module connected to the microwave optical receiver via a coupling module;

[0039] A linearization module, the linearization module is used to adjust the linearity of the low noise amplifier module;

[0040] The low noise amplification module includes an input matching network, a first amplification circuit, an inter-stage matching network, a second amplification circuit and an output matching network which are connected in sequence.

[0041] It should be noted that for a microwave optical receiver, its bandwidth depends on a low-noise amplifier. To this end, the utility model proposes a high-bandwidth, high-gain low-noise amplifier that can be used in the front end of a microwave optical receiver. The low-noise amplifier proposed in the utility model is connected to a microwave optical receiver through a coupling module, and the microwave optical receiver receives a microwave optical signal and converts it into an electrical signal, which is then coupled and the coupled signal is input into a low-noise amplifier module for amplification.

[0042] Among them, the low-noise amplifier module amplifies the signal through the first amplifier circuit and the second amplifier circuit to meet the high gain requirement; the low-noise amplifier module can effectively expand the matching bandwidth through the input matching network, the inter-stage matching network and the output matching network to meet the high bandwidth requirement of the microwave optical receiver.

[0043] Since the low-noise amplifier module sacrifices a part of its linearity when improving its efficiency, in order to balance the linearity and amplification efficiency, the utility model adjusts the linearity of the low-noise amplifier module through a linearization module, thereby maintaining a certain linearity balance while meeting high gain and high bandwidth.

[0044] In an optional embodiment, the coupling module includes a capacitor C1, a capacitor C2 and a resistor R1;

[0045] Among them, one end of the resistor R1 is connected to the microwave optical receiver, and the other end is connected to the positive electrode of the power supply; one end of the capacitor C1 is connected to the middle node between the resistor R1 and the power supply, and the other end is grounded; one end of the capacitor C2 is connected to the middle node between the resistor R1 and the microwave optical receiver, and the other end is connected to the input port of the low-noise amplifier module;

[0046] The input matching network includes: an inductor L1, an inductor L2 and a capacitor C3;

[0047] Among them, one end of the inductor L1 is connected to the first node, and the other end is grounded; one end of the inductor L2 is connected to the first node; one end of the capacitor C3 is connected to the first node, and the other end is grounded; the first node is connected to the capacitor C2.

[0048] It should be noted that the inductor L1, inductor L2 and capacitor C3 of the input matching network are connected to the same node, which is connected to the capacitor C2 in the coupling module. The coupled signal is matched by the input matching network and then output to the first amplifier circuit for amplification through the inductor L2.

[0049] The coupling module provided in this embodiment couples the detection signal received by the microwave optical receiver to the input port of the low noise amplifier module through the capacitor C2. The resistor R1 is used to connect the power supply to power the microwave optical receiver. The capacitor C1 is grounded to form a radio frequency loop.

[0050] In an optional embodiment, the first amplifying circuit includes: a capacitor C4, an inductor L3, a transistor Q1, a resistor R2 and a capacitor C5;

[0051] The capacitor C4 is connected to the gate of the transistor Q1; one end of the inductor L3 is connected to the middle node between the capacitor C4 and the gate of the transistor Q1, and the other end is grounded; the resistor R2 is connected to the source of the transistor Q1 in parallel with the capacitor C5.

[0052] It should be noted that the first amplifier circuit amplifies the signal through capacitor C4, inductor L3, transistor Q1, resistor R2 and capacitor C5. Among them, the first amplifier circuit adopts self-bias technology, provides zero potential through the grounded inductor L3, and raises the source potential to a DC potential equal to the voltage required by the gate and source through the source setting resistor R2. Since the introduction of resistor R2 will reduce the gain of the circuit and introduce additional noise, the resistor R2 is connected in parallel with the capacitor C5 in this embodiment, and the influence of the resistor R2 on the gain and noise is reduced by the capacitor C5.

[0053] Furthermore, the capacitor C5 in this embodiment is a capacitor with a larger capacity.

[0054] In an optional embodiment, the inter-stage matching network includes: a capacitor C6, and an inductor L4, a resistor R3 and a capacitor C7 connected in series in sequence;

[0055] The capacitor C6 is connected to the drain of the transistor Q1 ; the inductor L4 is connected to an intermediate node between the capacitor C6 and the drain of the transistor Q1 .

[0056] It should be noted that the purpose of the inter-stage matching circuit is to adjust the inter-stage matching. In this embodiment, the inter-stage matching circuit includes a capacitor C6, and an inductor L4, a resistor R3 and a capacitor C7 connected in series in sequence, and a voltage is connected between the resistor R3 and the capacitor C7.

[0057] The first amplifier circuit and the inter-stage matching circuit simplify the circuit, and the resistor R3 plays a negative feedback role, so that the circuit achieves a bias stabilization effect.

[0058] It should be noted that since the low noise amplifier provided by the utility model is used for microwave optical receivers, it is a high-frequency amplifier and has certain parasitic effects. If the source impedance does not match the load impedance, it will cause positive feedback and thus damage the equipment. In this embodiment, it is manifested as the negative resistance characteristic at the input end of the transistor Q1 causing the circuit to oscillate. Therefore, in this embodiment, the resistor R3 is introduced in the inter-stage matching circuit to overcome this problem.

[0059] In an optional embodiment, the second amplifier circuit includes: an inductor L5, a transistor Q2, a resistor R5 and a capacitor C9;

[0060] One end of the inductor L5 is connected to the capacitor C6 , and the other end is connected to the gate of the transistor Q2 ; the resistor R5 is connected to the capacitor C9 in parallel and then connected to the source of the transistor Q2 .

[0061] In an optional embodiment, the second amplifier circuit further includes a resistor R4, and the resistor R4 is connected to an intermediate node between the capacitor C6 and the inductor L5.

[0062] In an optional embodiment, the output matching network includes: an inductor L6, an inductor L7, an inductor L8, a capacitor C8, a capacitor C10, a capacitor C11 and a resistor R6;

[0063] Among them, the inductor L6 is connected in series with the capacitor C8, and the inductor L6 is connected to the drain of the transistor Q2; the inductor L8 and the capacitor C11 are connected in parallel to the middle node between the inductor L6 and the capacitor C8; the capacitor C10, the inductor L7 and the resistor R6 are connected in series in sequence, the capacitor C10 is connected to the middle node between the capacitor C6 and the inductor L5, and the resistor R6 is connected between the inductor L6 and the capacitor C11.

[0064] It should be noted that the purpose of the second amplifier circuit and the output matching circuit is to improve the overall circuit gain and output power, and at the same time, improve the flatness of the amplifier. In the output matching network, the inductor L6 and the capacitor C8 are connected in series and then connected to the drain of the transistor Q2, which is used as the output port of the second amplifier circuit. At the same time, the power supply is connected through the series capacitor C10, the inductor L7 and the resistor R6, and the series inductor L8 and the capacitor C11, so as to adjust the output matching and suppress the signal from flowing into the DC power supply port.

[0065] In an optional embodiment, the linearization module includes: a transistor Q3, a capacitor C12, a capacitor C13, a capacitor C14, a capacitor C15, a capacitor C16, a resistor R7, a resistor R8, an inductor L9 and an inductor L10;

[0066] Among them, the capacitor C12 is connected to the base of the transistor Q3, the inductor L9 is connected to the emitter of the transistor Q3, the capacitor C13 and the capacitor C14 are connected in parallel at both ends of the inductor L9, and the resistor R7 is connected in parallel with the capacitor C14; the capacitor C15 is connected in parallel with the inductor L10, one end of which is connected to the emitter of the transistor Q3, and the other end is connected to one end of the capacitor C16, and the other end of the capacitor C16 is connected to the resistor R8.

[0067] It should be noted that the linearization module is used to adjust the linearity of the low noise amplifier module. Its connection method is as follows: Figure 3 shown.

[0068] Specific circuits such as Figure 2 As shown, the collector of the transistor Q3 in the linearization module is used to receive the bias voltage, and the matching impedance is adjusted through the capacitor C13, capacitor C14, resistor R7 and inductor L9 connected to the emitter of the transistor Q3, as well as the capacitor C15, capacitor C16, inductor L10 and resistor R8, and the signal is output after passing through the resistor R8, and the signal is used to adjust the linearity of the low-noise amplifier module.

[0069] In an optional embodiment, the transistor Q3 is GaAs HBT.

[0070] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only the specific implementation method of the utility model and is not used to limit the protection scope of the utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A low noise amplifier for a front end of a microwave optical receiver, characterized in that: include: A low noise amplifier module connected to the microwave optical receiver via a coupling module; A linearization module, the linearization module is used to adjust the linearity of the low noise amplifier module; The low noise amplification module includes an input matching network, a first amplification circuit, an inter-stage matching network, a second amplification circuit and an output matching network which are connected in sequence.

2. A low noise amplifier for a microwave optical receiver front end according to claim 1, characterized in that: The coupling module includes a capacitor C1, a capacitor C2 and a resistor R1; Among them, one end of the resistor R1 is connected to the microwave optical receiver, and the other end is connected to the positive electrode of the power supply; one end of the capacitor C1 is connected to the middle node between the resistor R1 and the power supply, and the other end is grounded; one end of the capacitor C2 is connected to the middle node between the resistor R1 and the microwave optical receiver, and the other end is connected to the input port of the low-noise amplifier module; The input matching network includes: an inductor L1, an inductor L2 and a capacitor C3; Among them, one end of the inductor L1 is connected to the first node, and the other end is grounded; one end of the inductor L2 is connected to the first node; one end of the capacitor C3 is connected to the first node, and the other end is grounded; the first node is connected to the capacitor C2.

3. A low noise amplifier for a microwave optical receiver front end according to claim 2, characterized in that: The first amplifier circuit includes: a capacitor C4, an inductor L3, a transistor Q1, a resistor R2 and a capacitor C5; The capacitor C4 is connected to the gate of the transistor Q1; one end of the inductor L3 is connected to the middle node between the capacitor C4 and the gate of the transistor Q1, and the other end is grounded; the resistor R2 is connected to the source of the transistor Q1 in parallel with the capacitor C5.

4. A low noise amplifier for a front end of a microwave optical receiver according to claim 3, characterized in that: The inter-stage matching network includes: a capacitor C6, and an inductor L4, a resistor R3 and a capacitor C7 connected in series in sequence; The capacitor C6 is connected to the drain of the transistor Q1 ; the inductor L4 is connected to an intermediate node between the capacitor C6 and the drain of the transistor Q1 .

5. A low noise amplifier for a front end of a microwave optical receiver according to claim 4, characterized in that: The second amplifier circuit includes: an inductor L5, a transistor Q2, a resistor R5 and a capacitor C9; One end of the inductor L5 is connected to the capacitor C6 , and the other end is connected to the gate of the transistor Q2 ; the resistor R5 is connected to the capacitor C9 in parallel and then connected to the source of the transistor Q2 .

6. A low noise amplifier for a front end of a microwave optical receiver according to claim 5, characterized in that: The second amplifier circuit further includes a resistor R4 , and the resistor R4 is connected to an intermediate node between the capacitor C6 and the inductor L5 .

7. A low noise amplifier for a front end of a microwave optical receiver according to claim 5, characterized in that: The output matching network includes: inductor L6, inductor L7, inductor L8, capacitor C8, capacitor C10, capacitor C11 and resistor R6; Among them, the inductor L6 is connected in series with the capacitor C8, and the inductor L6 is connected to the drain of the transistor Q2; the inductor L8 and the capacitor C11 are connected in parallel to the middle node between the inductor L6 and the capacitor C8; the capacitor C10, the inductor L7 and the resistor R6 are connected in series in sequence, the capacitor C10 is connected to the middle node between the capacitor C6 and the inductor L5, and the resistor R6 is connected between the inductor L6 and the capacitor C11.

8. The low noise amplifier for a front end of a microwave optical receiver according to claim 1, characterized in that: The linearization module includes: transistor Q3, capacitor C12, capacitor C13, capacitor C14, capacitor C15, capacitor C16, resistor R7, resistor R8, inductor L9 and inductor L10; Among them, the capacitor C12 is connected to the base of the transistor Q3, the inductor L9 is connected to the emitter of the transistor Q3, the capacitor C13 and the capacitor C14 are connected in parallel at both ends of the inductor L9, and the resistor R7 is connected in parallel with the capacitor C14; the capacitor C15 is connected in parallel with the inductor L10, one end of which is connected to the emitter of the transistor Q3, and the other end is connected to one end of the capacitor C16, and the other end of the capacitor C16 is connected to the resistor R8.

9. A low noise amplifier for a front end of a microwave optical receiver according to claim 8, characterized in that: The transistor Q3 is GaAs HBT.

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