Optical power amplification system and its control method

Abstract

The present invention provides an optical power amplification system and a control method. The optical power amplification system includes: a beam system for providing independent first and second seed laser beams; an optical switch disposed on the transmission optical path of the second seed laser beam; an optical power amplifier disposed at the output end of the beam system; and an optical switch control device electrically connected to the optical power amplifier and the optical switch. Wherein, the optical power amplifier feeds back the output power of the first seed laser beam. When the output power is less than a predetermined value, the optical switch control device controls the optical switch to quickly turn on, and the second seed laser beam is transmitted into the optical power amplifier.

Description

Technical Field

[0001] The present invention relates to the technical field of lasers, and in particular, to an optical power amplification system and a control method thereof. Background Art

[0002] With the advantages of compact structure, strong anti-environmental interference ability, high conversion efficiency, and good beam quality, optical power amplifiers have important application values in basic scientific research, industrial processing, measurement and detection, etc. when combined with seed lasers. However, since there is no resonant cavity structure in fiber optic optical power amplifiers, when the pump is turned on and there is no seed light input, the fiber gain medium in the optical power amplifier will undergo self-excited oscillation, generating giant pulses, burning the fiber, and damaging the entire amplifier.

[0003] To solve this problem, the prior art usually adopts the method of real-time monitoring of the output power of the seed laser. When it is detected that the output power of the seed laser is lower than the set value, the pump diode of the optical power amplifier is turned off to avoid self-excited oscillation. However, it is difficult to implement this method in the optoelectronic separation state of the optical power amplifier. In the optoelectronic separation state, the circuit drive module needs to control the pump diode in the optical module through a connecting wire. When the length of the connecting wire is large, the transmitted signal is easily interfered, resulting in unstable voltage and current of the pump diode, and ultimately affecting the output power stability of the optical power amplifier. At this time, if a suitable capacitor is added to the circuit drive module, the voltage and current stability can be effectively improved, but it will also cause a delay when the circuit drive receives the signal of insufficient seed laser power and cuts off the pump diode, resulting in self-excited oscillation in the optical power amplifier.

[0004] In view of this, it is necessary to provide an optical power amplification system that can effectively overcome the problem of damage to the optical power amplifier caused by self-excited oscillation of the fiber gain medium in the optical power amplifier when there is no seed laser or the seed laser power is low. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides an optical power amplification system, which includes: a beam system for providing independent first and second seed laser beams; an optical switch disposed on the transmission optical path of the second seed laser beam; an optical power amplifier disposed at the output end of the beam system; and an optical switch control device electrically connected to the optical power amplifier and the optical switch. Wherein, the optical power amplifier feeds back the output power of the first seed laser beam. When the output power is less than a predetermined value, the optical switch control device controls the optical switch to quickly turn on, and the second seed laser beam is transmitted into the optical power amplifier.

[0006] In a preferred embodiment, the beam system includes: a seed laser for outputting a first seed laser beam; a spare seed laser for outputting a second seed laser beam; wherein, the seed laser and the spare seed laser are independent of each other.

[0007] In a preferred embodiment, the seed laser and the spare seed laser are in an always-on state, and the optical switch is in an always-off state when the output power is not less than the predetermined value.

[0008] In a preferred embodiment, the beam system includes: a seed laser and a beam splitter, and the laser beam output by the seed laser is split by the beam splitter into an independent first seed laser beam and a second seed laser beam.

[0009] In a preferred embodiment, a beam combiner is further included, and the beam combiner is located between the optical power amplifier and the beam system, wherein, the first seed laser beam and / or the second seed laser beam are combined into a single laser beam by the beam combiner and input into the optical power amplifier.

[0010] In a preferred embodiment, the beam combiner is selected from a fiber tapered beam combiner or a beam splitter combiner.

[0011] In a preferred embodiment, the optical switch includes an optical switch based on the electro-optic crystal effect or an optical switch based on the acousto-optic crystal effect.

[0012] In a preferred embodiment, the opening time of the optical switch is less than 10 ns.

[0013] In a preferred embodiment, a monitoring unit and a comparison unit are further included, and the monitoring unit converts the optical signal of at least one seed laser from the first seed laser beam into an electrical signal and then generates the output power;

[0014] The comparison unit compares the output power with the predetermined value and generates a switch control signal, and the optical switch is quickly turned on according to the switch control signal.

[0015] The present invention also provides a control method for an optical power amplification system, and the control method includes:

[0016] Providing independent first seed laser and second seed laser, the first seed laser is connected to the optical power amplifier, the second seed laser is connected to the optical power amplifier after passing through the optical switch, when the first seed laser operates normally, the optical switch is in an always-off state, and the second seed laser is in an always-on state;

[0017] Compare the output power of the first seed laser beam with a predetermined value;

[0018] If the output power is less than the predetermined value, control the optical switch to open quickly so that the second seed laser beam passes through the optical switch and enters the optical power amplifier.

[0019] Compared with the prior art, the present invention provides an optical power amplification system and a control method. The optical power amplification system includes two independent seed laser beams. When one seed laser beam is abnormal, the optical switch is quickly opened to control the other backup seed laser beam to be supplemented into the optical power amplifier, preventing the optical power amplifier from operating in a state without a seed laser or with too low output power of the seed laser, thereby effectively protecting the optical power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is a schematic diagram of the optical power amplification system in Embodiment 1 of the present invention.

[0022] Figure 2 It is a schematic diagram of the optical power amplification system in Embodiment 2 of the present invention.

[0023] Figure 3 It is a partial functional module diagram of the optical power amplification system of the present invention.

[0024] Figure 4 It is a flowchart of the control method of the optical power amplification system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to further understand the purpose, structure, features, and functions of the present invention, the following will be described in detail in conjunction with the embodiments.

[0026] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0027] In the existing fiber-based optical power amplification system, the seed laser of the seed laser source is input into an optical power amplifier (such as a fiber amplifier) through a transmission fiber. The seed laser interacts with the gain medium (such as a fiber gain medium) in the power amplifier for power amplification and then outputs high-power laser. Due to abnormalities in the seed laser source itself, or faults in the transmission fiber, other auxiliary devices, or circuit control modules between the seed laser source and the optical power amplifier, it may cause no seed laser to enter the optical power amplifier, or the power of the seed laser entering the optical power amplifier to become lower. At this time, it is easy for the gain medium in the optical power amplifier to generate self-excited oscillation, damaging the entire optical power amplification system.

[0028] To solve the above problems, the present invention additionally sets a group of standby seed lasers and an optical switch in the existing optical power amplification system. The standby seed lasers are also connected to the optical power amplifier. When the existing seed laser cannot be input into the optical power amplifier, or the output power of the existing seed laser input to the optical power amplifier is less than a certain set value, the optical switch is quickly turned on to control the standby seed laser to enter the optical power amplifier, ensuring that there is always a seed laser in the optical power amplifier and the power of the seed laser can meet the excitation requirements of the gain medium.

[0029] As Figure 1 shown, Embodiment 1 of the present invention provides a power amplifier system including a standby seed laser source 4.

[0030] Specifically, the optical power amplification system includes a beam system, an optical switch 5, an optical power amplifier 2, and an optical switch control device 6. The beam system is used to provide independent first and second seed laser beams. The optical switch 4 is disposed on the transmission optical path of the second seed laser beam. The optical power amplifier 2 is disposed at the output end of the beam system. The optical switch control device 6 is electrically connected to the optical switch 5 and the optical power amplifier 2. Among them, the optical power amplifier 2 feeds back the output power of the first seed laser beam. When the output power is less than a predetermined value, the optical switch control device 6 controls the optical switch 5 to quickly turn on, and the second seed laser beam is transmitted to the optical power amplifier 2.

[0031] In this embodiment, the beam system includes a seed laser source 1 and a standby seed laser source 4. The seed laser source 1 is used to output the first seed laser beam. The standby seed laser source 4 is used to output the second seed laser beam. Among them, the seed laser source and the standby seed laser source are independent of each other. Preferably, when the optical power amplification system is operating, both the seed laser source 1 and the standby seed laser source 4 are in the normally open state. Among them, the optical switch 5 is always in the normally closed state before receiving the control signal from the optical switch control device 6.

[0032] That is, by providing an independent backup seed laser 4 and corresponding control modules (optical switch 5 and optical switch control device 6), it is ensured that after the optical switch 5 is opened, the second seed laser beam output by the backup seed laser 4 can quickly enter the optical power amplifier 2 through the transmission optical fiber 8 for supplementation, thereby effectively avoiding the self-oscillation phenomenon caused by the absence of seed laser or the reduction of the output power of the seed laser in the gain medium of the optical power amplifier 2.

[0033] In this embodiment, the optical power amplifier 2 is, for example, an optical fiber amplifier, and the gain medium is, for example, a rare earth metal doped optical fiber.

[0034] In this embodiment, the frequency and wavelength of the first seed laser beam output by the seed laser 1 and the frequency and wavelength of the second seed laser beam output by the backup seed laser 4 may be the same or different, but the frequency and wavelength of the first seed laser beam and the frequency and wavelength of the second seed laser beam are both adapted to the energy level structure of the gain medium of the optical power amplifier 2.

[0035] In this embodiment, the seed laser 1 and the backup seed laser 4 can be two independent laser light sources respectively, and the two laser light sources generate seed laser beams with the same or different frequencies and wavelengths respectively.

[0036] In this embodiment, the optical switch 5 can be a mechanical optical switch, or an electro-optical switch composed of an electro-optical crystal and a drive power supply (such as an optical switch with electro-optical crystal effect), or an acousto-optic switch composed of an acousto-optic crystal and a drive power supply (such as an optical switch with acousto-optic crystal effect), or other types of optical switches that can switch the optical path. Among them, the opening time of the optical switch 5 is less than 10 ns (nanoseconds).

[0037] Continue to refer to Figure 1 , the optical power amplification system further includes a beam combiner 3, which is located between the optical power amplifier 2 and the beam system. Among them, the first seed laser beam of the seed laser 1 and the second seed laser beam of the backup seed laser 4 are combined into a beam by the beam combiner 3 and then input into the optical power amplifier 2.

[0038] In this embodiment, the beam combiner 3 is, for example, selected from fiber tapered beam combiners. Of course, according to actual usage needs, the beam combiner 3 can also be a beam splitter combiner.

[0039] In addition, transmission optical fibers (or passive optical fibers) 8 for transmitting the first seed laser beam and the second seed laser beam are respectively provided between the seed laser 1, the backup seed laser 4 and the beam combiner 3.

[0040] Refer to Figure 1 , the optical power amplifier 2 and the optical switch 5 can be electrically connected through the connection circuit 9 and the optical switch control device 6 respectively.

[0041] Combined Figure 1 and Figure 3 It can be seen that the optical power amplification system further includes a monitoring unit 20 and a comparison unit 10. The monitoring unit 20 converts the optical signal of at least one seed laser beam of the first seed laser beam from the seed laser 1 into an electrical signal and then generates the output power of the first seed laser beam. The comparison unit 10 is used to compare the above output power with a predetermined value. If it is determined that the output power is lower than the predetermined value, a switch control signal is generated, and the switch signal is transmitted to the optical switch control device 6. The optical switch control device 6 controls the optical switch 5 to quickly open, so that the second laser beam output by the backup seed laser 4 passes through the transmission optical fiber 8 and is input into the optical power amplifier 2 through the beam combiner 3 for supplementing the seed laser.

[0042] In this embodiment, the monitoring unit 20 may be an electronic circuit module integrated in the power amplifier 2. The electronic circuit module is electrically connected to the seed laser amplifier 1 through the connection circuit 9 and is used for performing optoelectronic conversion on the optical signal of at least one seed laser beam output from the seed laser amplifier 1 to form an electrical signal.

[0043] The comparison unit 10 may be integrated in the power amplifier 2; it may also be integrated in the switch control device 6 and form an independent electronic circuit module 40 with the switch control device 6; or, it may also be integrated in the monitoring unit 20.

[0044] In another embodiment of the present invention, the comparison unit 10 and the monitoring unit 20 may be used as a separately integrated electronic circuit module 30, which is arranged in the optical power amplification system and is electrically connected to the seed laser 1 and the switch control device 6 through the connection circuit 9.

[0045] Referring to Figure 2 , in Embodiment 2 of the present invention, an optical power amplification system is further provided. The difference between it and the optical power amplification system in Embodiment 1 shown in Figure 1 is that in the beam system, by providing a beam splitter 7 on the transmission optical path of the seed laser 1, the seed laser beam in the seed laser 1 is separated into a first seed laser beam and a second seed laser beam. That is, in this embodiment, the beam splitter 7 replaces the backup seed laser in Embodiment 1, and two independent seed laser beams are also formed. When the transmission of one of the laser beams is abnormal, the other backup seed laser beam can be quickly input into the optical power amplifier 2 to avoid the problem of damage to the optical power amplifier caused by self-excited oscillation of the gain medium in the optical power amplifier 2.

[0046] In Embodiment 2, the frequencies and wavelengths of the first seed laser beam and the second seed laser beam formed by the beam splitter 7 are the same.

[0047] Referring to Figure 4, the present invention also provides a control method 100 for the above optical power amplifier, which includes:

[0048] Providing independent first and second seed lasers. The first seed laser is connected to the optical power amplifier, and the second seed laser is connected to the optical power amplifier after passing through an optical switch. When the first seed laser operates normally, the optical switch is in a normally closed state, while the second seed laser is in a normally open state;

[0049] Comparing the output power of the first seed laser beam with a predetermined value;

[0050] If the output power is less than the predetermined value, controlling the optical switch to quickly turn on so that the second seed laser beam passes through the optical switch and enters the optical power amplifier.

[0051] Wherein, the control method 100 further includes: receiving an optical signal of at least one seed laser beam from the first seed laser beam; converting the optical signal into an electrical signal to generate the output power of the first seed laser beam.

[0052] The present invention provides an optical power amplification system and a control method. The optical power amplification system includes two independent seed laser beams. When one seed laser beam is abnormal, quickly turning on the optical switch to control the other backup seed laser beam can be supplemented into the optical power amplifier, preventing the optical power amplifier from operating in a state without a seed laser or with too low an output power of the seed laser, thereby effectively protecting the optical power amplifier.

[0053] The present invention has been described by the above related embodiments. However, the above embodiments are only examples of implementing the present invention. In addition, the technical features involved in different embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, changes and modifications made without departing from the spirit and scope of the present invention fall within the scope of patent protection of the present invention.

Claims

1. An optical power amplification system, characterized in that, The optical power amplification system includes: A beam system for providing a first seed laser beam and a second seed laser beam that are independent of each other; An optical switch disposed on the transmission optical path of the second seed laser beam; An optical power amplifier disposed at the output end of the beam system; and An optical switch control device electrically connected to the optical power amplifier and the optical switch; It further includes a monitoring unit and a comparison unit. The monitoring unit converts the optical signal of at least one seed laser from the first seed laser beam into an electrical signal and then generates an output power; The comparison unit compares the output power with a predetermined value and generates a switch control signal. The optical switch is quickly turned on according to the switch control signal; Wherein, when the first seed laser operates normally, the optical switch is in a normally closed state, while the second seed laser is in a normally open state; the optical power amplifier feeds back the output power of the first seed laser beam. When the output power is less than the predetermined value, the optical switch control device controls the optical switch to quickly turn on. The turn-on time of the optical switch is less than 10 ns, and the second seed laser beam quickly passes through the transmission optical fiber and is transmitted into the optical power amplifier for supplementation; The transmission optical fiber is a passive optical fiber.

2. The optical power amplification system according to claim 1, wherein The beam system includes: A seed laser for outputting a first seed laser beam; A spare seed laser for outputting a second seed laser beam; Wherein, the seed laser and the spare seed laser are independent of each other.

3. The optical power amplification system according to claim 2, wherein The seed laser and the spare seed laser are in a normally open state, and the optical switch is in a normally closed state when the output power is not less than the predetermined value.

4. The optical power amplification system according to claim 1, characterized in that, The beam system includes a seed laser and a beam splitter. The laser beam output by the seed laser is split by the beam splitter into a first seed laser beam and a second seed laser beam that are independent of each other.

5. The optical power amplification system according to claim 1, characterized in that It further includes a combiner located between the optical power amplifier and the beam system. Wherein, the first seed laser beam and / or the second seed laser beam are combined into a single laser beam by the combiner and input into the optical power amplifier.

6. The optical power amplification system according to claim 5, characterized in that The combiner is selected from a fiber taper combiner or a beam splitting plate combiner.

7. The optical power amplification system according to claim 1, characterized in that, The optical switch includes an optical switch based on the electro-optic crystal effect or an optical switch based on the acousto-optic crystal effect.

8. A control method for an optical power amplification system, characterized in that, The control method includes: Providing a first seed laser and a second seed laser that are independent of each other. The first seed laser is connected to an optical power amplifier, and the second seed laser is connected to the optical power amplifier after passing through an optical switch. When the first seed laser operates normally, the optical switch is in a normally closed state, while the second seed laser is in a normally open state; Providing a monitoring unit and a comparison unit. The monitoring unit converts the optical signal of at least one seed laser from the first seed laser beam into an electrical signal and then generates an output power; The comparison unit compares the output power of the first seed laser with a predetermined value; If the output power is less than the predetermined value, control the optical switch to quickly turn on, and the turn-on time of the optical switch is less than 10 ns, so that the second seed laser passes through the optical switch and quickly enters the optical power amplifier through the transmission optical fiber for augmentation. The transmission optical fiber is a passive optical fiber.

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