A method for miniaturizing a laser frequency stabilized light source and a laser frequency stabilized light source system thereof

Abstract

The application discloses a miniaturized laser frequency stabilization light source method and a laser frequency stabilization light source system thereof, and has the characteristics that a polarization spectrum frequency stabilization technology is used to lock outgoing laser on an atomic energy level spectrum line, and the outgoing laser from a laser chip is integrated with a miniaturized optical device to form a polarization spectrum frequency stabilization light path, wherein a miniaturized atomic gas chamber adopts an off-axis integral cavity output spectrum technology, high reflection films are coated on two ends to form an optical cavity, laser is incident to the optical cavity at a certain angle with an optical axis to realize multiple reflections, the propagation path length of probe light in the gas chamber is prolonged, the signal-to-noise ratio of a measured spectrum signal is improved, the light path after the gas chamber is reflected to a frequency stabilization circuit module end, and an embedded chip is combined with an algorithm to realize automatic locking of laser frequency. Compared with the prior art, the application has the advantages of simple structure, small size, high stability, and better application demand satisfaction of the frequency stabilization light source to precise measurement, and the application scenario of the laser interferometer in an industrial environment is widened.

Description

Technical Field

[0001] This invention relates to the field of laser frequency stabilization technology, specifically to a method for miniaturizing laser frequency stabilization light sources and a laser frequency stabilization light source system. Background Technology

[0002] Currently, laser interferometry technology plays a crucial role in semiconductor manufacturing, automotive manufacturing, aerospace, and other fields due to its advantages such as high precision and high efficiency. Among these advantages, the frequency stability of the laser source is one of the main factors limiting the measurement accuracy of laser interferometers.

[0003] Laser frequency stabilization technology selects a stable reference frequency standard. When the laser frequency to be locked deviates from the specific frequency standard, it identifies the deviation and generates an error signal reflecting this deviation. This error signal is then fed back to the laser system to be locked via a servo system, reducing the frequency drift of the laser output and achieving laser frequency locking. There are many methods for achieving laser frequency stabilization, such as saturated absorption spectroscopy based on atomic and molecular transition lines, polarization absorption spectroscopy, and PHD (Pound-Drever-Hall) stabilization, lock-in phase detection stabilization, and tit-locking stabilization based on the resonant frequency of optical resonators.

[0004] Existing laser frequency stabilization systems have large optical path areas, and the laser output from narrow-linewidth laser diodes has narrow linewidths and high coherence, making it impossible to maintain frequency stability for long periods. The center frequency will drift due to environmental factors and the device's own heating, which cannot meet the requirements of laser interferometers. Moreover, laser interferometers are large in size and have poor stability, limiting their widespread application in industrial environments. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by designing a method and system for miniaturized laser frequency-stabilized light sources. It employs a constant current drive source to control the frequency of the laser emitted from a high-precision laser chip, utilizes polarization absorption spectroscopy to identify the emitted laser frequency, and achieves frequency locking. By integrating a laser frequency stabilization module, the laser frequency is locked, meeting the application requirements of precision measurement. This miniaturized frequency-stabilized light source effectively solves the problems of maintaining long-term frequency stability and center frequency drift due to environmental factors and device heating. It greatly satisfies the needs of laser interferometers, and its small size and high stability further broaden the application scenarios of laser interferometers in industrial environments.

[0006] The objective of this invention is achieved as follows: a method for miniaturized laser frequency-stabilized light source, characterized by using a constant current drive source to control the frequency of the laser emitted from a high-precision laser chip, and utilizing polarization absorption spectroscopy technology to identify the frequency of the emitted laser and achieve laser frequency locking, specifically including the following steps:

[0007] Step 1: Use the constant current drive source in the frequency stabilization circuit module to control the high-precision laser chip to emit laser light.

[0008] Step 2: The light passes through a polarization spectral frequency-stabilized optical path composed of integrated miniaturized optical devices, and the polarization absorption spectral frequency-stabilization method is used to lock the emitted laser onto the atomic energy level spectral line.

[0009] Step 3: After the linearly polarized probe light is emitted from the micro atomic gas cell, it is split into two polarized beams, one vertical and one horizontal, after passing through the micro half-wave plate and the micro polarization beam splitter. The beams are then reflected by the reflector to the frequency stabilization module circuit.

[0010] The miniaturized atomic gas cell has high-reflectivity films coated at both ends to form an optical cavity. By using off-axis integrating cavity output spectroscopy, the laser is incident at a certain angle to the optical axis (horizontal angle of about 1.4° and pitch angle of about 1.6°) and is reflected multiple times in the gas cell, thereby extending the propagation path length of the probe light inside the gas cell and improving the signal-to-noise ratio of the measured spectral signal.

[0011] The frequency stabilization circuit module includes: a field-programmable gate array (FPGA), a constant current drive circuit, and a frequency stabilization drive circuit. It drives the laser chip through a constant current source and achieves precise control of the drive current by combining a negative feedback constant current drive circuit.

[0012] In the constant current drive circuit, the sampling resistor is connected in series with the high-precision laser chip to realize the IV conversion of the current flowing through the laser chip; in the frequency stabilization drive circuit, the integrated differential amplifier and adder realize the superposition of the triangular wave, DC bias component and feedback variable, and the feedback signal is connected to the constant current drive circuit through the FPGA to stabilize the laser frequency by controlling the current.

[0013] A miniaturized laser frequency-stabilized light source system is characterized by comprising: a frequency stabilization circuit module, a first miniature beam splitter, a second miniature beam splitter, a first miniature half-wave plate, a second miniature half-wave plate, a first miniature polarization beam splitter, a second miniature polarization beam splitter, a first miniature reflector, a second miniature reflector, a third vertical miniature reflector, a third horizontal miniature reflector, a fourth miniature reflector, a miniature quarter-wave plate, a miniature Rb atom gas cell, and a miniature collimating lens. The frequency stabilization circuit module superimposes a modulation signal onto the original scanning signal, which serves as the current drive signal for the laser to control a high-precision laser chip to drive linearly polarized light. The linearly polarized light is incident on the first miniature beam splitter via the first miniature reflector. The first miniature beam splitter splits the linearly polarized light into two paths: one path is directly emitted through the miniature collimating lens, and the other path is emitted through the first miniature half-wave plate and the first miniature quarter-wave plate. After adjustment by the polarization beam splitter, the light is divided into pump light and probe light. The pump light is modulated into circularly polarized light by a miniature quarter-wave plate. The circularly polarized light enters the miniature Rb atom gas cell in the reverse direction through the fourth miniature reflector and the second miniature beam splitter. The probe light enters the miniature Rb atom gas cell in the forward direction through the second miniature reflector and then enters the second miniature half-wave plate and the second miniature polarization beam splitter in sequence through the second miniature beam splitter. The second miniature polarization beam splitter divides the incident polarized light into vertically polarized light and horizontally polarized light. The vertically polarized light is reflected by the third vertical miniature reflector to the frequency stabilization circuit module. The horizontally polarized light is reflected by the third horizontal miniature reflector to the frequency stabilization circuit module. The frequency stabilization circuit module uses an integrated automatic frequency stabilization algorithm to determine whether the output laser frequency needs adjustment and uses a deep negative feedback constant current drive circuit to achieve precise control of the output laser frequency by the drive current.

[0014] Compared with existing technologies, this invention features a simple structure, small size, and high stability. By locking the laser frequency through a highly integrated laser frequency stabilization module, it provides a miniaturized, high-precision laser module for precision laser measurement technology. This enables the frequency-stabilized light source to better meet the application requirements of precision measurement and further broadens the application scenarios of laser interferometers in industrial environments. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the frequency stabilization circuit module;

[0017] Figure 3 This is a diagram of a miniaturized atomic gas chamber structure. Detailed Implementation

[0018] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art:

[0019] Example 1

[0020] See Figure 1 The miniaturized laser frequency-stabilized light source system of the present invention includes: a frequency stabilization circuit module (1), a first miniature beam splitter 2-1, a second miniature beam splitter 2-2, a first miniature half-wave plate 3-1, a second miniature half-wave plate 3-2, a first miniature polarization beam splitter 4-1, a second miniature polarization beam splitter 4-2, a first miniature reflector 5-1, a second miniature reflector 5-2, a third vertical miniature reflector 5-3-1, a third horizontal miniature reflector 5-3-2, a fourth miniature reflector 5-4, a miniature quarter-wave plate 6, a miniature Rb atom gas cell 7, and a miniature collimating lens 8. The frequency stabilization circuit module 1 superimposes the modulation signal onto the original scanning signal, which serves as the current driving signal for the laser to control the high-precision laser chip to drive the linearly polarized light. The linearly polarized light is incident on the first miniature beam splitter 2-1 via the first miniature reflector 5-1. The first miniature beam splitter 2-1 splits the linearly polarized light into two paths. One path of linearly polarized light is directly emitted through the miniature collimating lens 8, and the other path of linearly polarized light is emitted through the first miniature half-wave plate 8. After adjustment by waveplate 3-1 and the first micro polarization beam splitter 4-1, the light is divided into pump light and probe light. The pump light is modulated into circularly polarized light by micro quarter-wave plate 6 and enters micro Rb atom gas cell 7 in the opposite direction by fourth micro reflector 5-4 and second micro beam splitter 2-2. The probe light enters micro Rb atom gas cell 7 in the forward direction by second micro reflector 5-2 and enters second micro half-wave plate 3-2 and second micro polarization beam splitter 4-2 in sequence by second micro beam splitter 2-2. The second micro polarization beam splitter 4-2 divides the incident polarized light into vertically polarized light and horizontally polarized light. The vertically polarized light is reflected by third vertical micro reflector 5-3-1 to frequency stabilization circuit module 1, and the horizontally polarized light is reflected by third horizontal micro reflector 5-3-2 to frequency stabilization circuit module 1. Frequency stabilization circuit module 1 uses an integrated automatic frequency stabilization algorithm to determine whether the output laser frequency needs adjustment and uses a deep negative feedback constant current drive circuit to achieve precise control of the output laser frequency by the drive current.

[0021] This invention uses a constant current drive source to control the frequency of the laser emitted from the laser chip, and utilizes polarization absorption spectroscopy to identify the frequency of the emitted laser, thereby achieving laser frequency locking. Specifically, it includes the following steps:

[0022] Step 1: Use the constant current drive source in the frequency stabilization circuit module 1 to control the high-precision laser diode chip to emit laser light;

[0023] Step 2: Use the polarization absorption spectroscopy frequency stabilization method to lock the emitted laser onto the atomic energy level spectral line;

[0024] Step 3: The linearly polarized probe light is emitted from the micro atomic gas cell and then passes through the micro half-wave plate 3 and the micro polarization beam splitter 4 to split into two polarized beams, one vertical and one horizontal. The beams are then reflected by the reflector to the circuit terminal of the frequency stabilization module, which serves as the laser frequency stabilization source.

[0025] The frequency stabilization circuit module 1 uses a constant current drive source to control the laser emitted by the high-precision laser chip. Using polarization absorption spectroscopy technology, the frequency stabilization optical path and the micro Rb atom gas cell 7 identify the frequency of the emitted laser. The frequency is fed back to the constant current drive source through the frequency stabilization circuit module 1 to control the frequency of the laser emitted by the laser chip and achieve frequency locking.

[0026] The miniature Rb atom gas chamber 7 is fabricated using MEMS technology and employs off-axis integrating cavity output spectroscopy. High-reflectivity films are coated at both ends to form an optical cavity, allowing the laser to be incident at a certain angle to the optical axis (the horizontal angle is about 1.4° and the pitch angle is about 1.6°). The laser can be reflected multiple times inside the gas chamber, thereby extending the propagation path length of the probe light inside the gas chamber and improving the signal-to-noise ratio of the measured spectral signal.

[0027] The constant current drive source in the frequency stabilization circuit module 1 uses wavelength modulation technology to superimpose the modulation signal onto the original scanning signal, which serves as the current drive signal for the laser to control the high-precision laser chip to drive the X-ray polarized light.

[0028] See Figure 2 The frequency stabilization circuit module 1 includes: a field-programmable gate array (FPGA), a constant current drive circuit, and a frequency stabilization drive circuit. It achieves high-precision laser diode chip driving through a constant current source, and combines this with a negative feedback constant current drive circuit to achieve precise control of the drive current. In the constant current drive circuit, a sampling resistor is connected in series with the high-precision laser chip to achieve IV conversion of the current flowing through the laser chip. In the frequency stabilization drive circuit, an integrated differential amplifier and adder are used to superimpose the triangular wave, DC bias component, and feedback variable. The feedback signal is then connected to the constant current drive circuit via the FPGA to stabilize the laser frequency by controlling the current.

[0029] The frequency stabilization circuit module 1 integrates optical components onto a miniaturized physical chip, forming a miniaturized frequency-stabilized laser source. The miniaturized laser frequency-stabilized source module 1 designed in this embodiment has a volume of less than 30mm × 30mm × 20mm. The frequency stabilization circuit module 1 uses a high-precision laser diode chip to emit 780nm laser light.

[0030] See Figure 3The miniaturized atomic gas chamber has high-reflectivity films coated at both ends to form an optical cavity. By using off-axis integrating cavity output spectroscopy, the laser is incident at a certain angle to the optical axis (the horizontal angle is about 1.4° and the pitch angle is about 1.6°). Multiple reflections can be achieved inside the gas chamber, thereby extending the propagation path length of the probe light inside the gas chamber and improving the signal-to-noise ratio of the measured spectral signal.

[0031] The above embodiments are merely illustrative of the present invention and are not intended to limit the scope of the present invention. All equivalent implementations of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for miniaturizing a laser frequency-stabilized light source, characterized in that... This method uses a constant current drive source to control the frequency of the laser emitted from the laser chip, utilizes polarization absorption spectroscopy to identify the emitted laser frequency, and employs an embedded chip combined with an algorithm to achieve automatic laser frequency locking. Specifically, it includes the following steps: Step 1: Use the constant current drive source in the frequency stabilization circuit module to control the laser chip to emit laser light; Step 2: Use the polarization absorption spectroscopy frequency stabilization method to lock the emitted laser onto the atomic energy level spectral line; Step 3: The linearly polarized probe light is emitted from the miniature Rb atom gas cell and then passes through a miniature half-wave plate and a miniature polarization beam splitter to split into two polarized beams, one vertical and one horizontal. The beams are then reflected by a reflector to the circuit terminal of the frequency stabilization module, which serves as the laser frequency stabilization source.

2. The method for miniaturized laser frequency stabilization source according to claim 1, characterized in that... The micro Rb atom gas cell employs off-axis integrating cavity output spectroscopy technology. High-reflectivity films are coated at both ends to form an optical cavity, allowing the laser to be incident on the optical cavity at a horizontal angle of 1.4° and an elevation angle of 1.6°. Multiple reflections are achieved within the gas cell, thereby extending the propagation path length of the probe light inside the gas cell and improving the signal-to-noise ratio of the measured spectral signal.

3. The method for miniaturized laser frequency stabilization light source according to claim 1, characterized in that... The frequency stabilization circuit module integrates optical devices into a miniaturized physical chip to form a miniaturized frequency stabilization laser source.

4. The method for miniaturized laser frequency stabilization light source according to claim 1 or claim 3, characterized in that... The frequency stabilization circuit module includes: a field-programmable gate array (FPGA) circuit, a constant current drive circuit, and a frequency stabilization drive circuit. The sampling resistor in the constant current drive circuit is connected in series with the laser chip to realize the IV conversion of the current flowing through the laser chip. The frequency stabilization drive circuit, through integrated differential amplifier and adder, realizes the superposition of triangular wave, DC bias component and feedback variable, and connects the feedback signal to the constant current drive circuit through FPGA to stabilize the laser frequency by controlling the current.

5. A miniaturized laser frequency-stabilized light source system constructed by the method of miniaturized laser frequency-stabilized light source according to claim 1, characterized in that... The system includes: a frequency stabilization circuit module (1), a first miniature beam splitter (2-1), a second miniature beam splitter (2-2), a first miniature half-wave plate (3-1), a second miniature half-wave plate (3-2), a first miniature polarization beam splitter (4-1), a second miniature polarization beam splitter (4-2), a first miniature reflector (5-1), a second miniature reflector (5-2), a third vertical miniature reflector (5-3-1), a third horizontal miniature reflector (5-3-2), a fourth miniature reflector (5-4), a miniature quarter-wave plate (6), and a miniature... The Rb atom gas chamber (7) and the micro collimating lens (8) are used. The frequency stabilization circuit module (1) superimposes the modulation signal onto the original scanning signal and uses it as the current driving signal of the laser to control the high-precision laser chip to drive the linearly polarized light. The linearly polarized light is incident on the first micro reflector (5-1) and the first micro beam splitter (2-1). The first micro beam splitter (2-1) splits the linearly polarized light into two paths. One path of linearly polarized light is emitted directly through the micro collimating lens (8), and the other path of linearly polarized light is transmitted through the first micro half-wave plate (3-1) and the first micro polarization beam splitter. After adjustment, the device (4-1) splits the light into pump light and probe light. The pump light is modulated into circularly polarized light by a miniature quarter-wave plate (6) and enters the miniature Rb atom gas cell (7) in the opposite direction through the fourth miniature reflector (5-4) and the second miniature beam splitter (2-2). The probe light enters the miniature Rb atom gas cell (7) in the forward direction through the second miniature reflector (5-2). The two polarized lights are superimposed in the opposite direction in the miniature Rb atom gas cell (7) and then enter the second miniature half-wave plate (3-2) and the second miniature polarization beam splitter (4-5-1) in sequence through the second miniature beam splitter (2-2). -2); the second micro polarization beam splitter (4-2) divides the incident polarized light into vertically polarized light and horizontally polarized light. The vertically polarized light is reflected by the third vertical micro reflector (5-3-1) to the frequency stabilization circuit module (1), and the horizontally polarized light is reflected by the third horizontal micro reflector (5-3-2) to the frequency stabilization circuit module (1). The frequency stabilization circuit module (1) uses an integrated automatic frequency stabilization algorithm to determine whether the output laser frequency needs to be adjusted, and uses a deep negative feedback constant current drive circuit to achieve precise control of the drive current and output laser frequency.

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