CN111122124A

CN111122124A - Multi-channel synchronous characterization device and method based on semiconductor laser beams

Info

Publication number: CN111122124A
Application number: CN201911287418.4A
Authority: CN
Inventors: 王涛; 张浩然; 邓志磊; 孙嘉诚; 王相虎; 王高峰
Original assignee: Hangzhou Dianzi University
Current assignee: Hangzhou Dianzi University
Priority date: 2019-12-14
Filing date: 2019-12-14
Publication date: 2020-05-08

Abstract

The invention discloses a multichannel synchronous characterization device and method based on semiconductor laser beams, wherein a laser emission system is a laser to be tested, and an optical signal sampling system is divided into an optical system and a position control system; the data processing system consists of a computer and a set of software system. The method changes the time delay realized by distance difference in the traditional method into the time difference between two detection events of the detector as delay, applies a synchronous representation technology, simultaneously detects various parameters of the laser beam, uses a precise position controller to complete an automatic sampling process, greatly shortens the test time, and can integrate various parameter maps through a data processing system so as to analyze the local field distribution condition.

Description

Multi-channel synchronous characterization device and method based on semiconductor laser beams

Technical Field

The invention discloses a multi-channel synchronous characterization technology for laser beam characteristics, relates to an optical fiber coupling method and a data acquisition technology, and particularly relates to a multi-channel synchronous characterization device and method based on semiconductor laser beams.

Background

The laser is a light-emitting device capable of emitting good monochromaticity, high coherence, directivity and high intensity, and is widely applied to the fields of industrial cutting and etching, medical diagnosis and treatment, laser printing, micro-machining and the like at present, and the light-emitting quality of the laser directly influences the application effects. Therefore, it is very important to detect and analyze the laser and the laser characteristics. The characterization of laser beam is the most important means and technology for showing the advantages and disadvantages of laser and various performance indexes at present. Most of the current beam characterization techniques are from the beam intensity perspective to illustrate the quality of the beam. The method provided by the invention can respectively transmit the collected light beams to different analysis instruments for synchronous analysis by using the multi-channel light splitter. In addition, the whole laser beam is characterized in many aspects by the acquisition means capable of moving in two dimensions, so that the intensity distribution of a light field can be obtained, and the frequency distribution of a laser emission spectrum can be measured.

Disclosure of Invention

The invention provides a multi-channel synchronous characterization device and method based on semiconductor laser beams, aiming at further improving the quality of a resonant cavity of a laser and promoting the development of laser physics, wherein calibrated single-mode optical fibers are used for collecting light at a certain point in the laser beams, the collected light is divided and transmitted to different measuring and calculating instruments, the spectrum, the frequency spectrum and the polarization state of the point can be analyzed and displayed simultaneously, the collection and characterization of the whole beam are completed through a displacement device capable of accurately moving in a micro-scale manner, and the structure diagrams of the beam in different analysis aspects can be obtained through data integration, so that the follow-up research and analysis can be facilitated.

A multi-channel synchronous characterization device based on semiconductor laser beams comprises a laser light source emitting system, an optical signal sampling system, a multi-path analysis system and a data processing system. The laser light source emitting system is a laser to be tested; the optical signal sampling system is divided into an optical system and a position control system, wherein the optical system comprises a single-mode optical fiber, a collimator, a Faraday isolator and a multichannel light splitter; the position control system comprises a position controller and a computer control interface;

the laser emergent light is incident to the collimator, the emergent light of the collimator is incident to the input end of the Faraday isolator, the output end of the Faraday isolator is connected with the optical signal input end of the position controller through a single-mode optical fiber, the optical signal output end of the position controller is connected with the input end of the multi-channel analysis system through the multi-channel light splitter, the computer control interface of the position controller is connected with the computer, and the output end of the multi-channel analysis system is connected with the data processing system.

Preferably, the multiplex analysis system is a multiple optical characteristic analysis instrument.

Preferably, the optical characteristic analyzer includes an oscilloscope, a spectrum analyzer, and a polarization state analyzer.

Preferably, the multi-channel beam splitter consists of a 2X2 optical fiber coupler or a multi-channel coupler.

A multi-channel synchronous characterization method based on semiconductor laser beams comprises the following steps:

the laser realizes electric pumping through an external current source and realizes frequency stabilization through temperature control; laser emitted by a laser to be characterized emits far-field parallel light after being calibrated by a collimator, a single-mode optical fiber is stably fixed on a position controller, and a Faraday isolator is arranged between the laser and the single-mode optical fiber to prevent light from feeding back to a secondary pump laser; the position of the single-mode fiber in the space is adjusted to reach the optimal coupling state, namely the position is vertical to the propagation plane of the laser and is parallel to the transmission direction of the laser. Because the laser spot is in the range of hundreds of microns, the diameter of the single-mode fiber is only 5-8 microns, the diameter of the fiber is far smaller than that of the laser spot, and the fiber can be regarded as a point. In order to ensure stable sampling in the scanning process, the single-mode fiber stays at each point for a certain time to avoid instability caused by jitter. Controlling the position controller to perform displacement control on the single-mode optical fiber through a computer, and repeating the sampling process until the whole light beam sampling is completed; and the light after each sampling is respectively transmitted to a multi-path analysis system for analysis through a multi-channel light splitter, and after the analysis is finished, the data is transmitted to a computer for matrix processing to obtain a representation result.

Preferably, the position control system adopts a five-axis position controller, and the five-axis position controller is used for adjusting the front, back, left and right positions and realizing angle adjustment, so that the optical fiber and the laser achieve optimal coupling; the position control precision of the position controller is 0.1 μm.

Preferably, the sampling system needs to acquire at least a 50 × 50 matrix to generate a local field structure distribution characterization map.

The laser to be measured is a semiconductor laser emitting continuous waves, the measurable wavelength range is limited by an analysis instrument, and in addition, a light source needs to be firmly fixed to prevent the generation of errors caused by shaking.

In the optical signal sampling system, the selection of the optical fiber plays an important role in the device, which determines some key performance of the instrument. The sampling optical fiber can be a single-mode optical fiber or a multi-mode optical fiber, polarization analysis is allowed by using the polarization maintaining optical fiber, and the polarization state of the sampling optical fiber is maintained during propagation, which is determined according to actual requirements and the specification of a test instrument; the optical fiber coupler can use a single 2X2 optical fiber coupler, and can also use a plurality of double-channel optical fiber couplers; the five-axis position controller used by the position control system needs to be firmly fixed on a test bed, so that the vertical distance, the horizontal distance and the optical fiber angle can be adjusted.

In the multiplex analysis system, an analyzer to be used needs to be capable of outputting standard data in a predetermined format and to have an interface for communicating with a computer.

The invention has the advantages that: the invention innovatively applies the synchronous characterization technology, simultaneously detects various parameters of the laser beam, uses a precise position controller to complete an automatic sampling process, greatly shortens the testing time, and integrates various parameter maps through a data processing system so as to analyze the intensity/frequency distribution condition. The invention has simple structure, is flexible and applicable, and greatly reduces the cost.

Drawings

FIG. 1 is a schematic diagram of a multi-channel synchronous characterization device for laser beams according to the present invention.

FIG. 2 is a control program diagram of the apparatus for synchronously characterizing laser beams according to the present invention.

FIG. 3 shows the results obtained by the present invention applied to laser beam characterization: (a) laser beam intensity distribution map; (b) an emission wavelength distribution graph obtained by collecting the strongest peak of the emission spectrum of the laser; (c) an input-output curve corresponding to the point A in the intensity distribution diagram; (d) spectrum corresponding to the position of A point.

Detailed Description

The present invention will now be described in detail with reference to the accompanying drawings.

The invention provides a multichannel synchronous characterization technology for laser beams, which is characterized in that the system structure is shown in figure 1, and comprises a laser 1, a collimator 2, a Faraday isolator 3, a position controller 4, a multichannel optical fiber coupler 5, a polarization state analyzer 6, an oscilloscope 7, a spectrum analyzer 8, a spectrum analyzer 9 and a computer system 10, wherein the laser comprises a laser emission system, an optical signal sampling system, a multichannel analysis system and a data processing system. The laser emitting system comprises a laser 1, a power supply of the laser and a temperature controller of the laser; the optical signal sampling system comprises a collimator 2, a Faraday isolator 3, a position controller 4 and a multi-channel light splitter 5, wherein the collimator and the Faraday isolator ensure that light beams are effectively and accurately collected, and the position controller controls the movement of a sampling optical fiber to complete the whole sampling process; the multi-path analysis system comprises a polarization state analyzer 6, an oscilloscope 7, a spectrum analyzer 8 and a spectrum analyzer 9, and is used for analyzing each characteristic parameter of the sampled optical signal; the data processing system includes a computer system 10, and an expansion interface is required in consideration of different laboratory instruments supporting different communication interfaces.

The specific measurement method comprises the following steps: a switch of the laser 1 is opened to emit a laser light source, a light beam enters the collimator 2, and the Faraday isolator 2 effectively isolates the feedback of reflected light to the laser; the whole synchronous characterization process is controlled on a computer, the optical fiber is moved to a first preset sampling point by the position controller 4, sampling is started, after the sampling is completed, the computer indicates each

analysis instrument

6, 7, 8 and 9 to return data until the final sampling is completed, the computer summarizes and calculates to generate local field distribution, and instantaneous synchronous characterization characteristics can be obtained from the computer in the sampling process.

Fig. 2 is a flow chart of the computer control system, which shows a specific operation flow, and is not described in detail.

FIG. 3 is a test chart showing the results, (a) is an intensity distribution chart, and (b) is an emission wavelength distribution chart obtained by collecting the strongest peak of the emission spectrum of the laser; (c) an input-output curve corresponding to the point A in the intensity distribution diagram; (d) spectrum corresponding to the position of A point.

Claims

1. A multichannel synchronous characterization device based on semiconductor laser beams is characterized in that: the system comprises a laser light source emitting system, an optical signal sampling system, a multi-path analysis system and a data processing system; the laser light source emitting system is a laser to be tested; the optical signal sampling system is divided into an optical system and a position control system, wherein the optical system comprises an optical fiber, a collimator, a Faraday isolator and a multichannel light splitter; the position control system comprises a position controller and a computer control interface;

the laser emergent light is incident to the collimator, the emergent light of the collimator is incident to the input end of the Faraday isolator, the output end of the Faraday isolator is connected with the optical signal input end of the position controller through an optical fiber, the optical signal output end of the position controller is connected with the input end of the multi-channel analysis system through the multi-channel light splitter, the computer control interface of the position controller is connected with the computer, and the output end of the multi-channel analysis system is connected with the data processing system.

2. A multi-channel synchronous characterization device based on semiconductor laser beams, as claimed in claim 1, wherein: the multi-path analysis system is a plurality of optical characteristic analysis instruments.

3. A multi-channel synchronous characterization device based on semiconductor laser beams, as claimed in claim 1, wherein: the optical characteristic analysis instrument comprises an oscilloscope, a spectrum analyzer and a polarization state analyzer.

4. A multi-channel synchronous characterization device based on semiconductor laser beams, as claimed in claim 1, wherein: the multi-channel light splitter consists of a 2X2 optical fiber coupler or a multi-channel coupler.

5. A method as claimed in claim 1 for multi-channel simultaneous characterization of a semiconductor laser beam, wherein: the position controller adopts a five-axis position controller, and adjusts the front, back, left and right positions and realizes angle adjustment, so that the optical fiber and the laser achieve optimal coupling; the position control precision of the position controller is 0.1 μm.

6. A multi-channel synchronous characterization device based on semiconductor laser beams, as claimed in claim 1, wherein: the laser to be tested is a semiconductor laser emitting continuous waves.

7. A multi-channel synchronous characterization device based on semiconductor laser beams, as claimed in claim 1, wherein: the optical fiber is a single mode optical fiber or a multimode optical fiber.

8. A method as claimed in claim 1 for multi-channel simultaneous characterization of a semiconductor laser beam, wherein:

the laser realizes electric pumping through an external current source and realizes frequency stabilization through temperature control; after laser emitted by the laser is calibrated by the collimator, far-field parallel light is emitted, the optical fiber is stably fixed on the position controller, and a Faraday isolator is arranged between the laser and the optical fiber to prevent optical feedback; adjusting the position of the optical fiber in the space to achieve the optimal coupling state, namely the optical fiber is vertical to the propagation plane of the laser and is parallel to the transmission direction of the laser; controlling the position controller to perform displacement control on the optical fiber through the computer, and repeating the sampling process until the whole light beam sampling is completed; and the light after each sampling is respectively transmitted to a multi-path analysis system for analysis through a multi-channel light splitter, and after the analysis is finished, the data is transmitted to a computer for matrix processing to obtain a representation result.

9. A method as claimed in claim 8 for multi-channel simultaneous characterization of a semiconductor laser beam, wherein: the sampling system needs to collect at least a 50 x 50 matrix to generate a local field structure distribution representation diagram.