Multi-path high-stability narrow-linewidth external cavity semiconductor laser and application thereof

Abstract

The invention relates to a multi-path high-stability narrow-linewidth external cavity semiconductor laser and application thereof, and belongs to the technical field of lasers. The laser comprises two groups of external cavity light paths, Z-block beam combiners, partial reflectors and isolators, the two groups of external cavity light paths are arranged side by side, and the Z-block beam combiners, the partial reflectors and the isolators are sequentially arranged on the light emitting sides of the two groups of external cavity light paths; the external cavity optical path comprises a gain chip, a collimating lens, a polarization analyzer A, a polarization beam splitter, an F-P etalon and a narrow-band-pass filter which are sequentially arranged along the optical path. The polarization analyzer and the polarization beam splitter are arranged in the external cavity light path, main polarized light is kept to resonate in the external cavity light path, the polarization suppression ratio of the external cavity light path is improved, non-dominant mode noise is suppressed, and the line width is reduced; the mode jump risk is reduced, the device life is prolonged, and the power stability is improved; the beam quality is improved; and the polarization dependent loss in a light path is reduced.

Description

Technical Field

[0001] This invention relates to a multi-channel, high-stability, narrow-linewidth external cavity semiconductor laser and its applications, belonging to the field of laser technology. Background Technology

[0002] With the rapid development of optoelectronic technology, semiconductor lasers have wide applications in aerospace, materials processing, military, and medical fields. Narrow-linewidth semiconductor lasers, due to their narrow linewidth, low noise, high stability, high coherence, and good dynamic single-mode characteristics, have become core light source devices in long-distance space optical communication, high-sensitivity optical sensing, and energy detection, and have extremely wide applications in high-precision coherent lidar, precision fiber optic sensors, inter-satellite communication, and fiber optic coherent communication.

[0003] In the field of quantum precision measurement, systems requiring higher measurement accuracy place extremely high demands on laser stability, narrow linewidth, high power, and small-size integration. External cavity lasers are typically used to achieve the required narrow linewidth. However, in practical applications, external cavity lasers face demands for even narrower linewidths, higher polarization suppression ratios, higher mode stability, smaller size, and single-mode multi-wavelength operation. These are areas that urgently need improvement. Therefore, this invention is proposed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a multi-channel, high-stability, narrow-linewidth external cavity semiconductor laser and its applications.

[0005] The technical solution of the present invention is as follows: A multi-path high-stability narrow-linewidth external cavity semiconductor laser includes an external cavity optical path, a Z-block beam combiner, a partial mirror, and an isolator. The external cavity optical path is arranged in two parallel rows, and the Z-block beam combiner, a partial mirror, and an isolator are arranged sequentially on the light-emitting side of the two external cavity optical paths. The external cavity optical path includes a gain chip, a collimating lens, an analyzer A, a polarization beam splitter, an FP etalon, and a narrow bandpass filter arranged sequentially along the optical path.

[0006] An A+ polarization beam splitter is built into the external cavity optical path to preserve the main polarized light in internal resonance, improve the polarization suppression ratio of the external cavity optical path, and play a role in suppressing non-dominant mode noise, reducing linewidth, reducing the risk of mode hopping, extending device life, improving power stability, improving beam quality, and reducing polarization-related losses in the optical path.

[0007] Z-block beam combiners allow two beams of different wavelengths to be combined, enabling a simplified dual external cavity laser scheme within the same system, and extending the equivalent cavity length within a small size through multiple internal reflections.

[0008] According to a preferred embodiment of the present invention, the output light from analyzer A is aligned with the main polarization direction of the laser output light, allowing the maximum transmittance in the main polarization direction. Only the component of the laser in the main polarization direction can pass through the laser in other polarization directions, thereby improving the polarization suppression ratio.

[0009] According to a preferred embodiment of the present invention, the isolator includes an analyzer B, a magnetostrictive rotator, and an analyzer C arranged sequentially along the optical path. The analyzers B and C have the same polarization direction as the main polarization direction of the laser output light. After passing through the magnetostrictive rotator, the polarization direction is rotated by 45°, and then the light is emitted after passing through the analyzer C.

[0010] The application of the aforementioned multi-channel, high-stability, narrow-linewidth external cavity semiconductor laser follows these steps: (1) The gain chips of the two sets of external cavity optical paths are powered on to emit light. After the beam is shaped by the collimating lens, collimated light is obtained. After passing through the analyzer and polarization beam splitter, only the main polarized light is retained to resonate internally, reducing noise and improving stability. Then, it passes through the FP etalon and uses the FP etalon to obtain a wide free spectrum range and narrow bandwidth performance. The external cavity resonance spectrum is initially screened. Then, a narrow bandpass filter is used for single-mode selection and further compression of linewidth. (2) The two beams are combined by the Z-block beam combiner. The external cavity length is extended within a small size by multiple internal reflections. Then, the beams reach part of the mirrors to form the internal resonance of the complete external cavity laser. (3) The light beam exits after passing through the isolator.

[0011] According to a preferred embodiment of the present invention, in step (3), the beam passes through analyzer B, which has the same polarization direction as the laser beam, allowing the beam to pass normally. Then the beam passes through a magnetostrictive rotator, and after passing through the magnetostrictive rotator, the polarization direction is rotated by 45°. After passing through analyzer C, the reflected light is emitted. After passing through the magnetostrictive rotator, the polarization direction is rotated by 45° again, perpendicular to the polarization direction of analyzer B. The polarization component passing through is minimized, achieving maximum isolation of reflected light.

[0012] The beneficial effects of this invention are as follows: 1. This invention incorporates an analyzer and polarization beam splitter within the external cavity optical path, preserving the main polarized light in internal resonance, thereby improving the polarization suppression ratio of the external cavity optical path. This helps to suppress non-dominant mode noise, reduce linewidth, reduce the risk of mode hopping, extend device lifespan, improve power stability, enhance beam quality, and reduce polarization-related losses in the optical path.

[0013] 2. The present invention features a specially designed isolator to achieve maximum isolation of reflected light.

[0014] 3. This invention enables the application of single-module multi-wavelength lasers by incorporating a multi-channel Z-block beam combining prism; it provides different external cavity lengths to meet different wavelength requirements; and it utilizes the Z-block beam combining characteristics to extend the external cavity length and compress the linewidth within a small size. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the optical path propagation of the Z-block beam combiner of the present invention; The components are: 1. Gain chip; 2. Collimating lens; 3. Analyzer A; 4. Polarization beam splitter; 5. FP etalon; 6. Narrow bandpass filter; 7. Z-block beam combiner; 8. Partial reflector; 9. Analyzer B; 10. Magnetostrictive rotator; 11. Analyzer C. Detailed Implementation

[0016] The present invention will be further described below with reference to the embodiments and accompanying drawings, but is not limited thereto.

[0017] Example 1: like Figure 1 As shown, this embodiment provides a multi-channel high-stability narrow-linewidth external cavity semiconductor laser, including an external cavity optical path, a Z-block combiner 7, a partial reflector 8, and an isolator. The external cavity optical path is arranged in two parallel rows, and the Z-block combiner 7, the partial reflector 8, and the isolator are arranged sequentially on the light-emitting side of the two external cavity optical paths. The external cavity optical path includes a gain chip 1, a collimating lens 2, an analyzer A3, a polarization beam splitter 4, an FP etalon 5, and a narrow bandpass filter 6 arranged sequentially along the optical path.

[0018] An analyzer A3 and a polarization beam splitter 4 are built into the external cavity optical path to retain the main polarized light in internal resonance, improve the polarization suppression ratio of the external cavity optical path, and play a role in suppressing non-dominant mode noise, reducing linewidth, reducing the risk of mode hopping, extending device life, improving power stability, improving beam quality, and reducing polarization-related losses in the optical path.

[0019] Z-block beam combiners allow two beams of different wavelengths to be combined, enabling a simplified dual external cavity laser scheme within the same system, and extending the equivalent cavity length within a small size through multiple internal reflections.

[0020] The polarizer A3 outputs light with the same main polarization direction as the laser output, allowing maximum transmittance in the main polarization direction. Only the component of the laser with other polarization directions can pass through, thereby improving the polarization suppression ratio.

[0021] The isolator includes a polarizer B9, a magnetostrictive rotator 10, and a polarizer C11 arranged sequentially along the optical path. The polarizers B9 and C11 have the same polarization direction as the main polarization direction of the laser output. After passing through the magnetostrictive rotator 10, the polarization direction is rotated by 45°, and then the laser outputs after passing through the polarizer C11.

[0022] The application of the aforementioned multi-channel, high-stability, narrow-linewidth external cavity semiconductor laser follows these steps: (1) The gain chip 1 of the two sets of external cavity optical paths is powered on to emit light. After the beam is shaped by the collimating lens 2, it becomes collimated light. After passing through the analyzer 3 and the polarization beam splitter 4, only the main polarized light is retained to resonate internally, reducing noise and improving stability. Then it passes through the FP etalon 5. The FP etalon is used to obtain a wide free spectrum range and narrow bandwidth performance, and the external cavity resonance spectrum is initially screened. Then, the narrow bandpass filter 6 is used for single-mode selection and further compression of linewidth. (2) The two beams are combined by the Z-block beam combiner 7, and the external cavity length is extended within a small size by multiple internal reflections, and then reaches part of the reflecting mirror 8 to form the internal resonance of the complete external cavity laser. (3) The beam passes through the analyzer B9. The analyzer B9 has the same main polarization direction as the laser beam, allowing the beam to pass normally. Then the beam passes through the magnetostrictive rotator 10. After passing through the magnetostrictive rotator 10, the polarization direction is rotated by 45°. Then it passes through the analyzer C11 and exits. The reflected light returns and passes through the magnetostrictive rotator 10. The polarization direction is rotated by 45° again and is perpendicular to the polarization direction of the analyzer B9. The polarization component is minimized, achieving maximum isolation of reflected light.

Claims

1. A multi-channel, high-stability, narrow-linewidth external cavity semiconductor laser, characterized in that, It includes an external cavity optical path, a Z-block combiner, partial reflectors, and isolators. The external cavity optical path is arranged in two sets side by side, and the Z-block combiner, partial reflectors, and isolators are arranged sequentially on the light-emitting side of the two sets of external cavity optical paths. The external cavity optical path includes a gain chip, a collimating lens, an analyzer A, a polarization beam splitter, an FP etalon, and a narrow bandpass filter arranged sequentially along the optical path.

2. The multi-channel high-stability narrow-linewidth external cavity semiconductor laser as described in claim 1, characterized in that, The polarization direction of the light emitted from analyzer A is the same as that of the main polarization direction of the light emitted from the laser.

3. The multi-channel high-stability narrow-linewidth external cavity semiconductor laser as described in claim 2, characterized in that, The isolator includes a polarizer B, a magnetostrictive rotator, and a polarizer C arranged sequentially along the optical path. The polarizer B and polarizer C have the same main polarization direction as the laser output light. After passing through the magnetostrictive rotator, the polarization direction is rotated by 45°, and then the light is emitted after passing through the polarizer C.

4. The application of the multi-channel high-stability narrow-linewidth external cavity semiconductor laser as described in claim 3, characterized in that, The steps are as follows: (1) The gain chips of the two sets of external cavity optical paths are powered on to emit light. After the beam is shaped by the collimating lens, collimated light is obtained. After passing through the analyzer and polarization beam splitter, only the main polarized light is retained to resonate internally. Then, after passing through the FP standard, the external cavity resonance spectrum is initially screened. After that, a narrow bandpass filter is used for single-mode selection and further compression of the linewidth. (2) The two beams are combined by the Z-block beam combiner, and the external cavity length is extended by multiple internal reflections. Then the beams reach part of the mirror to form the internal resonance of the complete external cavity laser. (3) The light beam exits after passing through the isolator.

5. The application of the multi-channel high-stability narrow-linewidth external cavity semiconductor laser as described in claim 4, characterized in that, In step (3), the beam passes through analyzer B, which has the same polarization direction as the laser beam, allowing the beam to pass through normally. Then the beam passes through a magnetostrictive rotator, and after passing through the magnetostrictive rotator, the polarization direction is rotated by 45°. After passing through analyzer C, the beam is emitted. The reflected light returns and passes through the magnetostrictive rotator, and the polarization direction is rotated by 45° again, perpendicular to the polarization direction of analyzer B. The polarization component passing through is minimized, achieving maximum isolation of reflected light.

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