CN110265860B

CN110265860B - Menu laser with continuously adjustable repetition frequency derived from external trigger signal

Info

Publication number: CN110265860B
Application number: CN201910454908.2A
Authority: CN
Inventors: 杨祥辉; 王禹凝; 宋国龙; 原洋; 王丽鑫
Original assignee: Changchun New Industries Optoelectronics Tech Co ltd
Current assignee: Changchun New Industries Optoelectronics Tech Co ltd
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2021-05-25
Anticipated expiration: 2039-05-29
Also published as: CN110265860A

Abstract

The invention relates to a menu laser for realizing continuous and adjustable repetition frequency by deriving an external trigger signal, which is characterized by comprising the following specific steps of: 1) the signal acquisition module is used for acquiring a signal, sending the signal to an FPGA (field programmable gate array), simultaneously outputting one path of signal for driving a Q switch after the FPGA reads the signal, and outputting a second path of signal after delaying for a certain time, wherein the second path of signal is used for driving a laser; 2) the first path of signal drives a Q switch, and the path of signal is synchronous with the rising edge of an external signal; 3) and (4) delaying for a certain time after the first path of signal is output, outputting a first pulse of a second path of signal, and then outputting a second pulse again according to a frequency band in which the laser needs to work, wherein the period of the final output signal of the laser is kept synchronous with the first path of signal. The pulse input of any code can be realized, the pulse period interval control with high precision is achieved, and the relative delay of each laser signal and the input pulse signal is fixed.

Description

Menu laser with continuously adjustable repetition frequency derived from external trigger signal

Technical Field

The invention relates to a menu laser for realizing continuous and adjustable repetition frequency by deriving an external trigger signal, which is a method for realizing external trigger by menu laser pulse, namely, the external trigger signal is utilized to control the time sequence of an acousto-optic Q switch, and belongs to the field of optical electronics.

Background

MOPA lasers become a mainstream product in the laser market at present, but the repetition rate of the lasers is very high in order to avoid spontaneous radiation during amplification, and due to special applications, many users need low repetition rate output and need to use their own trigger signals to control synchronization, which requires pulse menu operation of the MOPA lasers. After the high-frequency laser is output, the high-frequency laser passes through a switch door with controllable time length, when the door is opened, the laser passes through, and when the door is closed, the laser cannot pass through, so that a pulse menu is realized.

The device for selecting the menu generally adopts an acousto-optic Q switch or an electro-optic Q switch, the door opening time sequence of the Q switch needs to be provided by a laser synchronous trigger signal, the desired pulse is selected from the MOPA laser, the time sequence of the MOPA laser is generally needed to be used for controlling the Q switch, a user cannot use external trigger, if the user forcibly wants to use the external trigger to control the Q switch, the time sequence of the Q switch is out of synchronization with the time sequence of the laser, if the door opening time is too short, the door opening time just occurs between two pulses, the selection missing situation occurs, and therefore no laser output exists.

At this time, many people will think of increasing the door opening time to ensure sufficient door opening time, and the laser pulse can enter the Q-switch door opening time period, which means that the Q-switch door opening time is longer than the laser period, and the door opening time is not only between two pulses, but at least covers more than one period.

The method can actually select the pulse without laser, but the timing sequence of Q switch gate given by the user every time is irregular because the signal is not synchronous laser. Since the gate-on time is greater than one period of the laser pulse, if the rising edge of the gate-on time occurs before the first pulse and the falling delay of the gate-on time occurs just after the second pulse, which is possible without doubt, there will be a case where one more pulse is selected, and two pulses are selected for each gate-on time.

In addition to the above, using the synchronization signal of the laser to control the gate-on time of the Q-switch does not allow continuous adjustability of the low repetition rate. For example, a 10kHz laser pulse, one for every ten pulses, the frequency of the outgoing laser pulse is 1kHz, one for every ten pulses, the frequency of the laser pulse is 909Hz, one for every twelve pulses, and the frequency is 833Hz, and so on, the frequency of the outgoing laser pulse is always separated, not continuous, which may affect the user, and some key experimental results may not be observed.

Disclosure of Invention

The invention aims to provide a menu laser for realizing continuous and adjustable repetition frequency by deriving an external trigger signal, which realizes the pulse input of arbitrary coding, achieves very high-precision pulse period interval control and can achieve the relative constant delay of each laser signal and an input pulse signal.

The technical scheme of the invention is realized as follows: a menu laser device with continuously adjustable repetition frequency derived from an external trigger signal collects a coding signal or a frequency signal provided outside the laser device; the method is characterized by comprising the following specific steps:

1. sending the acquired signals into an FPGA (field programmable gate array), reading the rising edge of an external signal by the FPGA, simultaneously outputting one path of signal for driving a Q switch, and outputting a second path of signal after delaying for a certain time, wherein the second path of signal is used for driving a laser;

2. the first path of signal drives the Q switch, and the path of signal is synchronous with the rising edge of the external signal, so that the repetition frequency of the path of signal is consistent with that of the external signal; the pulse width needs to be set appropriately. The pulse width is too small, so that the Q switch cannot be well driven, and the pulse width is too large, so that a plurality of laser pulses can possibly appear;

3. the second path of signal drives the laser, after the first path of signal is output, the first pulse of the second path of signal is output after delaying for a certain time, then according to the frequency band that the laser needs to work, in this scheme, the laser needs to work at 10KHz, namely, the period is 100us, which requires the second path of signal to output the first pulse, and then the second pulse is output again through 100us, and so on, until the FPGA acquires the rising edge of the next external signal, the second path of signal stops; duplicate content 3 and content 4;

4. the period of the final output signal of the laser keeps synchronous with the first path of signal, namely the output frequency of the laser is consistent with the frequency of the input signal; because the laser signal and the second path of signal keep synchronous, the time delay between the laser signal and the input signal is fixed. Therefore, the laser output of the MOPA laser with low repetition frequency, high accuracy and high stability is realized.

The invention has the advantages that the output of the laser under low repetition frequency is realized by utilizing a synchronous derivative signal method, different repetition frequencies can be realized, the repetition frequency can be continuously adjusted, the output of light pulses with different central wavelengths can be realized, and the output frequency of the laser can be controlled by an external trigger signal of a user; the continuous adjustable repetition frequency of the single-pulse laser can be realized; and the output of the pulse laser with different central wavelengths and low repetition frequency can be realized by changing different Q switches and lasers. The method is used for military laser radar alarm exercise, radar ranging and the like.

Drawings

FIG. 1 is a schematic diagram of the signal derivation of the present invention.

FIG. 2 is a diagram illustrating the Q-switch driving of the present invention.

FIG. 3 is a schematic diagram of the laser driving of the present invention.

FIG. 4 is a schematic diagram of laser delay control output according to the present invention.

Detailed Description

The invention is further described with reference to the following figures and examples: as shown in fig. 1 to 4, a menu laser device with derived external trigger signal and continuously adjustable repetition frequency collects a coded signal or a frequency signal provided outside the laser device; the method is characterized by comprising the following specific steps:

The frequency of the user is collected first, and then the high electrical frequency ratio time of the frequency is adjusted to be less than the pulse period of one laser. Next, starting with each pulse and starting with the laser pulse period, the generation of the trigger signal for the same high electrical frequency time interval is started until the next pulse stops, as shown in fig. 1. Thereby obtaining two trigger signals. The first trigger signal is used to drive the Q-switch as shown in fig. 2, and has the same period as the collected signal. The second signal drives the laser, and since the Q-switch needs a certain time to be stable, the widths of T1 and T2 must be appropriate, and T3 is the signal width output according to the required operating frequency of the laser. As shown in fig. 3, the second signal drives the laser to cause the laser to output a laser output at a high repetition rate. As shown in fig. 3, finally, the laser passes through the Q switch, as shown in fig. 4, since the Q gate-on time of the high-frequency laser at this time passes, the period of the laser signal is the same as that of the input signal, and the delay between each laser signal and the external input signal is stable, and the other frequency signal is continuously adjustable, a random trigger signal can be provided from the outside of the user.

Claims

1. A menu laser device with continuously adjustable repetition frequency derived from an external trigger signal collects a coding signal or a frequency signal provided outside the laser device; the method is characterized by comprising the following specific steps:

1) sending the acquired signals into an FPGA (field programmable gate array), reading the rising edge of an external signal by the FPGA, simultaneously outputting one path of signal for driving a Q switch, and outputting a second path of signal after delaying for a certain time, wherein the second path of signal is used for driving a laser;

2) the first path of signal drives the Q switch, and the path of signal is synchronous with the rising edge of the external signal, so that the repetition frequency of the path of signal is consistent with that of the external signal; the pulse width needs to be set to be proper;

3) the second path of signal drives the laser, after the first path of signal is outputted, the first pulse of the second path of signal is outputted after a certain time delay, then according to the frequency section that the laser needs to work, the laser needs to work at 10KHz, namely the frequency section with the period of 100us, so that the second path of signal is required to output the first pulse and then output the second pulse again through 100us, and so on, until the FPGA acquires the rising edge of the next external signal, the second path of signal stops; repeating the step 3;

4) the period of the final output signal of the laser keeps synchronous with the first path of signal, namely the output frequency of the laser is consistent with the frequency of the input signal; because the laser signal and the second path of signal keep synchronous, the time delay between the laser signal and the input signal is fixed.