A method for calibrating the center wavelength of a semiconductor laser

Abstract

The application belongs to the technical field of wavelength calibration, and discloses a method for calibrating the central wavelength of a semiconductor laser, which comprises the following steps: step S1, customizing a standard gas chamber; step S2, preliminary debugging; and step S3, calibrating the central wavelength. The method calibrates the output wavelength of the semiconductor laser by setting a relatively low-cost spectrometer, a standard gas chamber and two photodetectors, avoids using an expensive wavelength meter, simplifies the cumbersome calibration steps, and tunes the output wavelength of the semiconductor laser by controlling the laser controller through an electrical signal, thereby avoiding the use of precise, expensive, poor-stability and low-consistency optical tuning components, and effectively improving the calibration efficiency of the semiconductor laser wavelength and the equipment purchase cost.

Description

Technical Field

[0001] This invention relates to the field of wavelength calibration technology, and more specifically, to a method for calibrating the center wavelength of a semiconductor laser. Background Technology

[0002] The conventional method involves precisely measuring the center wavelength of a semiconductor laser using a wavelength meter. By adjusting its electrical parameters, the wavelength is tuned to the specified wavelength point, and the operating parameters are then determined. This method is a direct measurement approach, requiring a high-precision wavelength meter. However, the calibration process necessitates tuning the output laser velocity using optical tuning components such as FP cavities and etalons. While these devices offer precise measurements, they suffer from poor stability and consistency, often requiring repeated tuning and comparisons. This cumbersome and inefficient process, coupled with the high cost of the equipment, significantly increases the cost of debugging semiconductor lasers for businesses. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for calibrating the center wavelength of a semiconductor laser. This method offers advantages such as a simple measurement process, accurate wavelength calibration, and relatively low equipment purchase costs. It effectively solves the technical problems in existing technologies, such as expensive equipment, cumbersome and time-consuming calibration processes, and poor stability and consistency of optical tuning components.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for calibrating the center wavelength of a semiconductor laser includes the following steps:

[0006] Step S1: Customize a standard air chamber.

[0007] Customize a standard gas cell so that its absorption wavelength corresponds to the wavelength point to be calibrated, and set this as λ. c , serving as a precise reference for wavelength;

[0008] Step S2, Initial debugging,

[0009] A precision controller is used to precisely control the temperature and drive current of the semiconductor laser, and a spectrometer is used to measure its center wavelength. After adjusting the temperature and waiting for it to stabilize, the magnitude of the drive current is gradually changed so that the center wavelength of the semiconductor laser output gradually approaches the desired wavelength. When the center wavelength of the semiconductor laser output approaches, but has not yet exceeded, λ... c At this time, record the magnitude of the driving current ILD1 and the center wavelength λ1. When the center wavelength exceeds λ... c Then, record the driving current ILD2 and the center wavelength λ2 at this time;

[0010] Step S3: Calibrate the center wavelength.

[0011] The laser output from the semiconductor laser in the above steps is split into two paths by an optical fiber beam splitter. One path is directly connected to the first photodetector as a power reference, and the other path is first connected to the second photodetector after passing through a standard gas chamber. Based on the electrical parameter values ​​obtained in step S2 and keeping the temperature constant, the laser is scanned with the original driving current as the center.

[0012] During the scanning process, the outputs of the first and second photodetectors are precisely sampled. When the laser scan passes through the absorption peak of the standard gas cell, the output of the second photodetector relative to the first photodetector is at its minimum. The electrical parameters at this time are recorded, which are the operating parameters of the semiconductor laser at that wavelength.

[0013] Furthermore, by adjusting the values ​​of ILD1 and ILD2, i.e., adjusting the starting and ending values ​​of the driving current during the scanning of the semiconductor laser, the absorption peak of the standard gas cell is positioned at the middle scale line. At this point, the output wavelength of the semiconductor laser can be determined to be within λ. c Operating parameters: Operating temperature is the set temperature, controlled by a temperature controller. .

[0014] Furthermore, using the electrical parameter values ​​from step two as a reference and keeping the temperature constant, a scan is performed with the original drive current as the center, ranging from ±1 to 10 mA. The more precise the scan step, the more accurate the measurement value.

[0015] Furthermore, the outputs of the first photodetector and the second photodetector are precisely sampled using an oscilloscope.

[0016] Furthermore, the precision controller includes a temperature controller and a laser driver.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] This invention calibrates the output wavelength of a semiconductor laser by using a relatively low-cost spectrometer, a standard gas chamber, and two photodetectors, avoiding the use of expensive wavelength meters and simplifying the cumbersome calibration process. Furthermore, it uses an electrical signal to control the laser controller to tune the output wavelength of the semiconductor laser, avoiding the use of precision, expensive, unstable, and inconsistent optical tuning components. This effectively improves the calibration efficiency of semiconductor laser wavelengths and reduces equipment purchase costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the prior art structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the device structure of the present invention;

[0022] Figure 3 This is a flowchart of the method of the present invention;

[0023] Figure 4 This is a screenshot of the monitoring section of an oscilloscope.

[0024] Explanation of reference numerals in the attached figures: 1. Semiconductor laser; 2. Laser driver; 3. Temperature controller; 4. Spectrometer; 5. Fiber optic beam splitter; 6. Standard gas chamber; 7. Second photodetector; 8. First photodetector. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0030] Example

[0031] See attached document Figure 1-4 As shown, the purpose of this invention is to solve the problems existing in the above-mentioned technology and to provide a method for calibrating the center wavelength of a semiconductor laser 1. The specific steps of this method are now described in detail using a DFB laser as an example:

[0032] Step 1: Customize a standard gas cell 6, and set the absorption wavelength of the standard gas cell 6 to correspond to the wavelength point to be calibrated as λ. c This serves as a precise reference value for the wavelength;

[0033] Step 2: Initial debugging. A precision controller is used to precisely control the temperature and drive current of semiconductor laser 1. A spectrometer 4 is used to measure its center wavelength. After adjusting the temperature and waiting for it to stabilize, the drive current is gradually changed so that the center wavelength output by semiconductor laser 1 gradually approaches the desired wavelength. When the center wavelength output by semiconductor laser 1 approaches, but has not yet exceeded, λ... c At this time, record the magnitude of the driving current ILD1 and the center wavelength λ1. When the center wavelength exceeds λ... c Then, record the driving current ILD2 and the center wavelength λ2 at this time;

[0034] Based on the above tests, there must be a λ1 < λ. c <λ2, which also means that when the temperature remains constant, when the driving current of semiconductor laser 1 scans from ILD1 to ILD2, the output wavelength of the laser will also scan from λ1 to λ2, and will necessarily sweep through λ2. cThis process can be perfectly achieved through a precision controller that includes a temperature controller 3 and a laser driver 2.

[0035] Step 3: Connect the output of semiconductor laser 1 to the circuit as follows: Figure 2 Make precise adjustments using the wavelength calibration device shown:

[0036] The wavelength calibration device consists of an optical fiber beam splitter 5, a first photodetector 8, and a second photodetector 7. The laser is first split into two paths by the beam splitter. One path is directly connected to the first photodetector 8 as a power reference, and the other path is connected to the second photodetector 7 after passing through the standard gas chamber 6.

[0037] The laser output from semiconductor laser 1 in the above steps is split into two paths by fiber beam splitter 5. One path is directly connected to the first photodetector 8 as a power reference, and the other path first passes through the standard gas chamber 6 and then connects to the second photodetector 7. Based on the electrical parameter values ​​obtained in step two and keeping the temperature constant, scanning is performed with the original driving current as the center.

[0038] During the scanning process, the outputs of the first photodetector 8 and the second photodetector 7 are precisely sampled. When the laser scan passes through the absorption peak of the standard gas cell 6, the output of the second photodetector 7 relative to the first photodetector 8 is at its minimum. The electrical parameters at this time are recorded, which are the operating parameters of the semiconductor laser 1 at that wavelength.

[0039] Based on the electrical parameters obtained in step two, and with the temperature kept constant, the driving current is adjusted by the laser driver 2 to scan from ILD1 to ILD2. The more precise the scanning step, the better the measurement effect.

[0040] As can be seen from the preliminary adjustment process in step two, during the scanning process, the output wavelength of semiconductor laser 1 must pass through λ. c The absorption peak of standard gas cell 6 is λ. c Therefore, when the output wavelength of semiconductor laser 1 is λ c At that time, the output of the second photodetector 7 is at its minimum relative to the first photodetector 8;

[0041] Therefore, during the scanning process, the outputs of the first photodetector 8 and the second photodetector 7 are precisely sampled using an oscilloscope, such as... Figure 4 As shown, when the laser scan passes through the absorption peak of the standard gas cell 6, the output of the second photodetector 7 relative to the first photodetector 8 is at its minimum. Record the electrical parameters at this point; this is the operating point of the semiconductor laser 1 at that wavelength.

[0042] By adjusting the values ​​of ILD1 and ILD2, i.e., adjusting the start and end values ​​of the drive current scan of semiconductor laser 1, the absorption peak is positioned at the middle scale line of the oscilloscope. At this point, the output wavelength of the laser can be determined to be within λ. c The operating parameters at this location, the operating temperature is the set temperature of semiconductor laser 1 at this time. .

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calibrating the center wavelength of a semiconductor laser, characterized in that, Includes the following steps: Step S1: Customize a standard air chamber. Customize a standard gas cell so that its absorption wavelength corresponds to the wavelength point to be calibrated, and set this as λ. c , serving as a precise reference for wavelength; Step S2, Initial debugging, A precision controller is used to precisely control the temperature and drive current of the semiconductor laser, and a spectrometer is used to measure its center wavelength. After adjusting the temperature and waiting for it to stabilize, the magnitude of the drive current is gradually changed so that the center wavelength of the semiconductor laser output gradually approaches the desired wavelength. When the center wavelength of the semiconductor laser output approaches, but has not yet exceeded, λ... c At this time, record the magnitude of the driving current ILD1 and the center wavelength λ1. When the center wavelength exceeds λ... c Then, record the driving current ILD2 and the center wavelength λ2 at this time; Step S3: Calibrate the center wavelength. The laser output from the semiconductor laser in the above steps is split into two paths by an optical fiber beam splitter. One path is directly connected to the first photodetector as a power reference, and the other path is first connected to the second photodetector after passing through a standard gas chamber. Based on the electrical parameter values ​​obtained in step S2 and keeping the temperature constant, the laser is scanned with the original driving current as the center. During the scanning process, the outputs of the first and second photodetectors are precisely sampled. When the laser scan passes through the absorption peak of the standard gas cell, the output of the second photodetector relative to the first photodetector is at its minimum. The electrical parameters at this time are recorded, which are the operating parameters of the semiconductor laser at that wavelength.

2. The method for calibrating the center wavelength of a semiconductor laser according to claim 1, characterized in that, By adjusting the values ​​of ILD1 and ILD2, i.e., adjusting the starting and ending values ​​of the driving current during the scanning of the semiconductor laser, the absorption peak of the standard gas cell is positioned at the middle scale line. At this point, the output wavelength of the semiconductor laser can be determined to be within λ. c Operating parameters: Operating temperature is the set temperature, controlled by a temperature controller. .

3. The method for calibrating the center wavelength of a semiconductor laser according to claim 2, characterized in that, Using the electrical parameter values ​​from step two as a reference, and keeping the temperature constant, scan with ±1 to 10mA centered on the original drive current. The more precise the scan step, the more accurate the measurement value.

4. The method for calibrating the center wavelength of a semiconductor laser according to claim 3, characterized in that, The outputs of the first photodetector and the second photodetector are precisely sampled using an oscilloscope.

5. The method for calibrating the center wavelength of a semiconductor laser according to claim 1, characterized in that, The precision controller includes a temperature controller and a laser driver.

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