阅读说明：本技术 一种光纤光栅激光器驰豫振荡抑制方案 (Scheme for suppressing relaxation oscillation of fiber grating laser ) 是由 郭亚池 李冬 钟丽芳 于 2021-08-30 设计创作，主要内容包括：本发明提供了一种光纤光栅激光器驰豫振荡抑制方案,包括：分光器、光电探测器、跨阻放大器、放大器、相位调制电路；所述分光器用于使得一部分输出信号光进入光电探测器中,所述光电探测器将这一部分输出信号光转换电流信号；所述电流信号再经过跨阻放大器转换成电压信号后再通过放大器进行放大；所述相位调整电路对放大后的电压信号进行相位调整生成驰豫振荡抑制电压信号,所述驰豫振荡抑制电压信号的相位与驰豫振荡信号相差180°；所述驰豫振荡抑制电压信号接入对泵浦驱动的恒流源电路,以对驰豫振荡信号进行抑制。上述的光纤光栅激光器驰豫振荡光路结构,用于抑制光栅输出驰豫振荡信号,用于提高超窄线宽激光器的RIN噪声。(The invention provides a fiber grating laser relaxation oscillation suppression scheme, which comprises the following steps: the device comprises a light splitter, a photoelectric detector, a trans-impedance amplifier, an amplifier and a phase modulation circuit; the optical splitter is used for enabling a part of output signal light to enter a photoelectric detector, and the photoelectric detector converts the part of output signal light into a current signal; the current signal is converted into a voltage signal through a trans-impedance amplifier and then amplified through an amplifier; the phase adjusting circuit performs phase adjustment on the amplified voltage signal to generate a relaxation oscillation suppression voltage signal, and the phase of the relaxation oscillation suppression voltage signal is 180 degrees different from that of the relaxation oscillation signal; the relaxation oscillation suppression voltage signal is connected to a constant current source circuit driven by a pump so as to suppress the relaxation oscillation signal. The fiber grating laser relaxation oscillation optical path structure is used for inhibiting grating output relaxation oscillation signals and improving RIN noise of the ultra-narrow line width laser.)

1. A fiber grating laser relaxation oscillation suppression scheme, comprising: the device comprises a light splitter, a photoelectric detector, a trans-impedance amplifier, an amplifier and a phase modulation circuit;

the optical splitter is used for enabling a part of output signal light to enter a photoelectric detector, and the photoelectric detector converts the part of output signal light into a current signal; the current signal is converted into a voltage signal through a trans-impedance amplifier and then amplified through an amplifier; the phase adjusting circuit performs phase adjustment on the amplified voltage signal to generate a relaxation oscillation suppression voltage signal, and the phase of the relaxation oscillation suppression voltage signal is 180 degrees different from that of the relaxation oscillation signal; the relaxation oscillation suppression voltage signal is connected to a constant current source circuit driven by a pump so as to suppress the relaxation oscillation signal.

2. The fiber grating laser relaxation oscillation suppression scheme of claim 1 wherein: and the cathode of the photoelectric detector is connected with the output end of the optical splitter, and the anode of the photoelectric detector is connected with the negative input end of the transimpedance amplifier.

3. The fiber grating laser relaxation oscillation suppression scheme of claim 2 wherein: the positive electrode input end of the trans-impedance amplifier is grounded, a resistor is connected between the negative electrode of the trans-impedance amplifier and the output end of the trans-impedance amplifier, and the resistor is connected with a capacitor in parallel.

4. A fiber grating laser relaxation oscillation suppression scheme as claimed in claim 3 wherein: the phase modulation circuit comprises a 90-180 DEG phase shift circuit and a 180-270 DEG phase shift circuit.

5. The fiber grating laser relaxation oscillation suppression scheme of claim 4 wherein: the laser also comprises a syntropy adder, wherein the relaxation oscillation suppression voltage signal is input to an LD _ AC _ BACK end of the syntropy adder and is superposed with a direct current signal LD _ DC _ SET output by a DAC of the single chip microcomputer, so that the laser generates a current signal with an opposite phase, and a signal with an opposite phase to the relaxation oscillation signal is further optically generated to suppress the relaxation oscillation signal.

Technical Field

The invention relates to a relaxation oscillation suppression scheme of a fiber grating laser.

Background

The ultra-narrow linewidth laser has larger aspects in distributed optical fiber sensing, laser radar, underwater listening and the like, and has the advantages of long gain area, compact structure, high energy density, strong anti-electromagnetic interference, small temperature expansion coefficient, no need of heat dissipation and the like.

Because the high-performance single longitudinal mode narrow linewidth fiber laser has wide application requirements in sensitive fields such as military and the like, the fiber laser has extremely important significance in terms of the core technology and the core material, the prohibition of Chinese implementation, the limitation of product import, the research, the development, the construction and the development of the single longitudinal mode narrow linewidth fiber laser and the equipment production line with the independent intellectual property rights in China.

The method has the following defects:

the current fiber grating laser has RIN noise peak at the relaxation oscillation position, so that if the customer needs the information of the frequency point in the use of the customer, the tested signal in the frequency has strong interference signal. RIN noise suppression of the relaxation oscillation signal is required.

Disclosure of Invention

The invention provides a relaxation oscillation suppression scheme for a fiber grating laser, which is used for suppressing a relaxation oscillation signal output by a grating and improving the RIN noise of an ultra-narrow linewidth laser.

In order to solve the above technical problem, the present invention provides a fiber grating laser relaxation oscillation suppression scheme, including: the device comprises a light splitter, a photoelectric detector, a trans-impedance amplifier, an amplifier and a phase modulation circuit;

the optical splitter is used for enabling a part of output signal light to enter a photoelectric detector, and the photoelectric detector converts the part of output signal light into a current signal; the current signal is converted into a voltage signal through a trans-impedance amplifier and then amplified through an amplifier; the phase adjusting circuit performs phase adjustment on the amplified voltage signal to generate a relaxation oscillation suppression voltage signal, and the phase of the relaxation oscillation suppression voltage signal is 180 degrees different from that of the relaxation oscillation signal; the relaxation oscillation suppression voltage signal is connected to a constant current source circuit driven by a pump so as to suppress the relaxation oscillation signal.

In a preferred embodiment: and the cathode of the photoelectric detector is connected with the output end of the optical splitter, and the anode of the photoelectric detector is connected with the negative input end of the transimpedance amplifier.

In a preferred embodiment: the positive electrode input end of the trans-impedance amplifier is grounded, a resistor is connected between the negative electrode of the trans-impedance amplifier and the output end of the trans-impedance amplifier, and the resistor is connected with a capacitor in parallel.

In a preferred embodiment: the phase modulation circuit comprises a 90-180 DEG phase shift circuit and a 180-270 DEG phase shift circuit.

In a preferred embodiment: the laser also comprises a syntropy adder, wherein the relaxation oscillation suppression voltage signal is input to an LD _ AC _ BACK end of the syntropy adder and is superposed with a direct current signal LD _ DC _ SET output by a DAC of the single chip microcomputer, so that the laser generates a current signal with an opposite phase, and a signal with an opposite phase to the relaxation oscillation signal is further optically generated to suppress the relaxation oscillation signal.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

1. the invention provides a relaxation oscillation suppression scheme for a fiber grating laser, which adopts high-speed operational amplifier to carry out TIA circuit design and can completely restore relaxation oscillation signals.

2. The invention provides a relaxation oscillation suppression scheme of a fiber grating laser, which adopts a specially designed phase shift circuit to carry out phase shift from 90 degrees to 270 degrees, and simultaneously adds a digital potentiometer to carry out phase adjustment through software.

3. The invention provides a relaxation oscillation suppression scheme for a fiber grating laser, and the whole relaxation oscillation signal can achieve the suppression effect of about 25 dB.

4. The invention provides a relaxation oscillation suppression scheme of a fiber grating laser, which has lower cost and does not need to increase suppression devices of an optical path scheme.

Drawings

FIG. 1 is a diagram of the structure of the relaxation oscillation optical path of a fiber grating laser in the preferred embodiment of the present invention;

FIG. 2 is a circuit diagram of a transimpedance amplifier according to a preferred embodiment of the present invention;

FIG. 3 is a 90-180 phase shift circuit diagram in a preferred embodiment of the present invention;

FIG. 4 is a diagram of a 180-270 phase shifting circuit in a preferred embodiment of the present invention;

fig. 5 is a circuit diagram of a current source in a preferred embodiment of the invention.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention; it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and all other embodiments obtained by those skilled in the art without any inventive work are within the scope of the present invention.

In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top/bottom", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," "sleeved/connected," "connected," and the like, are used in a broad sense, and for example, "connected" may be a wall-mounted connection, a detachable connection, an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, and a communication between two elements, and those skilled in the art will understand the specific meaning of the terms in the present invention specifically.

Referring to fig. 1-5, the present invention provides a fiber grating laser relaxation oscillation suppression scheme, comprising: the device comprises a light splitter, a photoelectric detector, a trans-impedance amplifier, an amplifier and a phase modulation circuit;

the optical splitter is used for enabling a part of output signal light to enter a photoelectric detector, and the photoelectric detector converts the part of output signal light into a current signal; the current signal is converted into a voltage signal through a trans-impedance amplifier and then amplified through an amplifier; the phase adjusting circuit performs phase adjustment on the amplified voltage signal to generate a relaxation oscillation suppression voltage signal, and the phase of the relaxation oscillation suppression voltage signal is 180 degrees different from that of the relaxation oscillation signal; the relaxation oscillation suppression voltage signal is connected to a constant current source circuit driven by a pump so as to suppress the relaxation oscillation signal.

In this embodiment, the whole bandwidth of the circuit needs to be considered during design, and since the signal frequency of the relaxation oscillation signal is about 250KHz, the operational amplifier with higher bandwidth and lower Ibias needs to be considered in the selection of the operational amplifier of the transimpedance amplifier, and the signal rate is increased by adopting a reverse bias connection method.

Specifically, the cathode of the photodetector is connected to the output end of the optical splitter, and the anode of the photodetector is connected to the negative input end of the transimpedance amplifier. The positive electrode input end of the trans-impedance amplifier is grounded, a resistor is connected between the negative electrode of the trans-impedance amplifier and the output end of the trans-impedance amplifier, and the resistor is connected with a capacitor in parallel.

Since the overall phase shift is about 180 degrees, a circuit for reserving a phase shift of 90 to 270 degrees is required, and thus the phase modulation circuit includes a 90-180 ° phase shift circuit and a 180-270 ° phase shift circuit, and the specific circuit diagrams are shown in fig. 3 and 4.

In this embodiment, the laser further includes a unidirectional adder, and the relaxation oscillation suppression voltage signal is input to an "LD _ AC _ BACK" end of the unidirectional adder and is superimposed with a direct current signal "LD _ DC _ SET" output by a DAC of the single chip microcomputer, so that the laser generates a current signal with an opposite phase, and further generates a signal with an opposite phase to the relaxation oscillation signal optically, so as to suppress the relaxation oscillation signal.

The above description is only a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto, and any person skilled in the art can make insubstantial changes in the technical scope of the present invention within the technical scope of the present invention, and the actions infringe the protection scope of the present invention are included in the present invention.