Picosecond optical fiber optical parametric oscillator based on acousto-optic wavelength tuning
By using an acousto-optic wavelength-tunable picosecond fiber optical parametric oscillator, the problems of complex light source structure, low output power, large spectral width, and small tuning range in CARS microscopic imaging systems have been solved, realizing narrow-spectrum high-power picosecond laser output and expanding its application scenarios in biomedical detection and material composition detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING WEIKUAI PHOTONICS TECH CO LTD
- Filing Date
- 2025-10-16
- Publication Date
- 2026-04-21
AI Technical Summary
In existing CARS microscopy imaging systems, fiber laser-based light sources suffer from problems such as complex structure, low output power, large spectral width, and small tuning range, which limit their application in biomedical detection and material composition detection.
Picosecond fiber optical parametric oscillators based on acousto-optic wavelength tuning are used, and the mode-locked laser seed source, narrow-spectrum high-power tunable pump source, and fiber optical parametric resonator are coordinated and controlled through an embedded integrated control platform to achieve narrow-spectrum high-power tunable picosecond laser output.
It achieves narrow-spectrum high-power picosecond fiber laser output with continuously adjustable wavelengths from 1035 to 1065 nm, featuring a wide spectral tuning range and high output power, making it suitable for CARS imaging systems.
Smart Images
Figure CN224153760U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of fiber laser technology, specifically to a picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning. Background Technology
[0002] Microscopic imaging technology has long played a crucial role in the development of modern biomedicine. Coherent anti-Stokes Raman scattering (CARS) is a label-free, highly specific, and non-invasive nonlinear optical imaging technique widely applicable to the study of biological tissue and cell structures, metabolic imaging, and tumor identification. CARS imaging systems utilize two laser beams of different frequencies to illuminate a sample, acquiring chemical and structural information through the resulting Raman scattering. Compared to traditional Raman scattering imaging techniques, CARS can enhance the signal by up to 1 million times and achieve imaging up to 10 cm⁻¹. -1 High spectral resolution and microsecond-level imaging speed have led to their widespread application in materials science and biomedical research. Solid-state laser-based CARS imaging systems, however, suffer from complex laser source structures, large size, high cost, poor stability, and require regular maintenance, limiting their application to laboratory settings. In contrast, fiber laser-based CARS imaging sources offer a reduction in size by more than three times, a cost reduction of approximately 50%, extremely high system stability, and excellent beam quality. They can replace existing solid-state lasers, expanding applications in material composition analysis and becoming a major technological solution for novel CARS light sources in biomedical and material composition detection.
[0003] Common fiber optic sources in CARS microscopy systems include fiber lasers based on principles such as soliton self-frequency shift (SSFS), dispersive waves, supercontinuum generation (SCG), four-wave mixing (FWM), fiber optical parametric amplifiers (FOPA), and fiber optical parametric oscillators (FOPO). Among these, SSFS-based sources can achieve continuous, wide-range tuning output, but the output pulse power is wavelength-dependent, exhibiting wavelength delay correlation, and has a broad spectrum, limiting the spectral resolution of CARS imaging. Dispersive wave-based sources can achieve continuous blue-shift wavelength tuning, but the tuning range is relatively small. SCG-based sources have non-uniform spectral energy density, low output power, and high nonlinear noise, typically requiring the use of filters for wavelength tuning. Light sources based on FWM, FOPA, and FOPO can achieve all-fiber, time-synchronized output. However, FWM and FOPA-based light sources have a wider output spectrum and lower energy conversion efficiency compared to FOPO. FOPO light sources have advantages such as high spectral resolution, high energy conversion efficiency, time-synchronized collinear output, and a large tuning range, making them suitable for CARS microscopic imaging systems.
[0004] As a crucial component of microscopic imaging systems, advancements in light sources can significantly improve system performance. Currently, common light sources in CARS microscopic imaging systems can be categorized into solid-state laser-based and fiber laser-based sources. Solid-state laser-based sources are bulky, expensive, unstable, and require regular maintenance, limiting the application of CARS imaging technology to the laboratory. Fiber laser-based sources still face challenges in simultaneously achieving simple structure, high output power, narrow spectral width, and wide tuning range. Compared to other fiber laser technologies, FOPO offers advantages such as high energy conversion efficiency, narrow spectral width, and a wide tuning range. Therefore, developing novel FOPO light sources for CARS microscopic imaging is of great significance for the advancement of CARS microscopic imaging technology. Utility Model Content
[0005] The purpose of this invention is to provide a picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning to solve the problems mentioned in the background art.
[0006] To achieve the above objectives, this utility model provides the following technical solution: a picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning, comprising an embedded integrated control platform, wherein the embedded integrated control platform coordinates and controls a mode-locked laser seed source, a narrow-spectrum high-power tunable pump source, and a fiber optical parametric resonant cavity; the mode-locked laser seed source uses a mode-locked laser oscillator as the seed source, and a tunable spectral filter and a laser amplifier are set after the mode-locked laser seed source. The tunable spectral filter can also be set in the resonant cavity of the mode-locked laser oscillator, and a laser amplifier is set after the mode-locked laser oscillator to obtain a narrow-spectrum high-power tunable pulsed laser, which serves as the narrow-spectrum high-power tunable pump source;
[0007] The mode-locked laser seed source is connected to a coupler, which is connected to two circulators. Port 2 of both circulators is connected to an acousto-optic tunable filter, and the acousto-optic tunable filter is connected to a preamplifier. The preamplifier is connected to a fiber optic mirror. Port 3 of both circulators is connected to a single-mode fiber, and the two single-mode fibers are connected to a main amplifier. After collimation, the main amplifier is followed by a dichroic mirror, a half-glass slide, and an isolator. After one of the isolators, a half-glass slide and a dichroic mirror are followed in sequence. The dichroic mirror is followed by a half-glass slide, a mirror, a collimator, a single-mode fiber, a collimator, and a mirror. At the same time, the dichroic mirror is also followed by a mirror, a half-glass slide, a collimator, a photonic crystal fiber, a lens, and a dichroic mirror in sequence.
[0008] Preferably, the mode-locked laser seed source has a repetition frequency of ~40MHz and a spectral coverage range of 1035-1065nm.
[0009] Preferably, the mode-locked laser seed source is connected to an optical fiber coupler to split into two paths. The splitting ratio of the optical fiber coupler is 50 / 50. Both paths are connected to a fiber laser dual-pass preamplifier, and a tunable spectral filter is connected in the fiber laser dual-pass preamplifier.
[0010] Preferably, the laser amplifier includes a fiber laser preamplifier and a fiber laser main amplifier, with the fiber laser preamplifier connected to the fiber laser main amplifier, and a single-mode fiber is added between the fiber laser preamplifier and the fiber laser main amplifier to stretch the pulse in the time domain.
[0011] Preferably, the narrow-spectrum high-power tunable pump source couples 1μm pump light into a photonic crystal fiber, generates idler light through a four-wave mixing process, performs 0-degree processing at the tail of the photonic crystal fiber, and outputs the idler light from the collimator after passing through a single-mode fiber. After being reflected by a mirror on the displacement stage, it is recoupled into the single-mode fiber and returns to the photonic crystal fiber. The mirror on the displacement stage and the 0-degree end face reflection of the fiber crystal fiber respectively constitute the two end faces of the linear cavity of the fiber optical parametric oscillator.
[0012] Compared with the prior art, the beneficial effects of this utility model are:
[0013] (1) Based on wide-spectrum mode-locking, multi-pass fiber laser saturated gain amplification, acousto-optic tunable filtering and narrow-spectrum high-power fiber laser amplification, narrow-spectrum high-power fiber laser output with continuously adjustable wavelength of 1035-1065nm is realized.
[0014] (2) By taking into account the four-wave mixing optical parametric gain, the rapid adjustment of the pump light center wavelength, the rapid adjustment of the optical delay line, and the optical fiber parametric conversion efficiency, picosecond fiber laser output with a wavelength of 785-985nm can be achieved. Attached Figure Description
[0015] Figure 1 This is a conceptual diagram of the technical route of this utility model;
[0016] Figure 2 This is a system structure diagram of the present invention. Detailed Implementation
[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0018] Please see Figure 1-2 This utility model provides a technical solution: a picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning, comprising an embedded integrated control platform. The embedded integrated control platform coordinates and controls a mode-locked laser seed source, a narrow-spectrum high-power tunable pump source, and a fiber optical parametric resonant cavity. The mode-locked laser seed source uses a mode-locked laser oscillator as the seed source. A tunable spectral filter and a laser amplifier are set after the mode-locked laser seed source. The tunable spectral filter can also be set in the resonant cavity of the mode-locked laser oscillator. A laser amplifier is set after the mode-locked laser oscillator to obtain a narrow-spectrum high-power tunable pulsed laser. The narrow-spectrum high-power tunable pulsed laser serves as the narrow-spectrum high-power tunable pump source.
[0019] The mode-locked laser seed source is connected to a coupler, which is connected to two circulators. Port 2 of both circulators is connected to an acousto-optic tunable filter, and the acousto-optic tunable filter is connected to a preamplifier. The preamplifier is connected to a fiber optic mirror. Port 3 of both circulators is connected to a single-mode fiber, and the two single-mode fibers are connected to a main amplifier. After collimation, the main amplifier is followed by a dichroic mirror, a half-glass slide, and an isolator. After one of the isolators, a half-glass slide and a dichroic mirror are followed in sequence. The dichroic mirror is followed by a half-glass slide, a mirror, a collimator, a single-mode fiber, a collimator, and a mirror. At the same time, the dichroic mirror is also followed by a mirror, a half-glass slide, a collimator, a photonic crystal fiber, a lens, and a dichroic mirror in sequence.
[0020] In this invention, the mode-locked laser seed source has a repetition frequency of ~40MHz and a spectral coverage range of 1035-1065nm.
[0021] In this invention, the mode-locked laser seed source is connected to an optical fiber coupler to split into two paths. The splitting ratio of the optical fiber coupler is 50 / 50. Both paths are connected to a fiber laser dual-pass preamplifier after the optical fiber coupler, and a tunable spectral filter is connected in the fiber laser dual-pass preamplifier.
[0022] In this invention, the laser amplifier includes a fiber laser preamplifier and a fiber laser main amplifier. The fiber laser preamplifier is connected to the fiber laser main amplifier, and a single-mode fiber is added between the fiber laser preamplifier and the fiber laser main amplifier to broaden the pulse in the time domain. The fiber laser main amplifier realizes 1μm high-power narrow-spectrum tunable picosecond laser output.
[0023] In this invention, the narrow-spectrum high-power tunable pump source couples 1μm pump light into a photonic crystal fiber, generates idler light through a four-wave mixing process, and the end of the photonic crystal fiber is treated at 0 degrees, resulting in 4% end-face reflection. Therefore, the idler light reaches the dichroic mirror after end-face reflection, and is reflected and coupled into the single-mode fiber by the dichroic mirror. After passing through the single-mode fiber, the idler light is output from the collimator, reflected by the mirror on the shift stage, and recoupled into the single-mode fiber and back into the photonic crystal fiber. The mirror on the shift stage and the 0-degree end-face reflection of the fiber crystal fiber constitute the two end faces of the linear cavity of the fiber optical parametric oscillator.
[0024] This invention allows for fine-tuning of the cavity length of a fiber optic parametric oscillator by adjusting the displacement stage, controlling the different spectral components of the idler light to coincide with the pump light in time and space, thereby changing the oscillation wavelength of the fiber optic parametric resonator. Combined with tuning the center wavelength of the 1μm pump light, the output wavelength of the fiber optic parametric oscillator can be tuned.
[0025] To achieve picosecond laser output with a wide tuning range, narrow spectral width, and high output power, this invention proposes a new technical solution. The conceptual diagram of the technical roadmap is shown below. Figure 1 As shown, a mode-locked laser oscillator is first constructed as a seed source. A tunable spectral filter and a laser amplifier are then placed after the seed source to obtain a narrow-spectrum, high-power tunable pulsed laser. Alternatively, a narrow-spectrum, high-power tunable pulsed laser can be obtained by placing the tunable spectral filter in the resonant cavity of the mode-locked laser oscillator and placing a laser amplifier after the mode-locked laser oscillator. Then, the narrow-spectrum, high-power tunable pulsed laser is used as a pump source to construct a fiber optical parametric oscillator based on nonlinear fiber to achieve idler frequency oscillation output. Furthermore, an embedded integrated control platform is set up to achieve idler frequency tunable output by coordinating the control of the center wavelength of the pump source, the cavity length of the mode-locked laser seed source, or the cavity length of the optical parametric resonator.
[0026] Specific examples of system architecture include: Figure 2 As shown, a broadband fiber mode-locked laser is used as a seed source with a repetition frequency of ~40MHz and a spectral coverage of 1035-1065nm. After the seed source, a fiber coupler is connected to split the laser into two paths with a splitting ratio of 50 / 50. After the fiber coupler, both paths are connected to a fiber laser double-pass preamplifier. An acousto-optic tunable filter (AOTF) is connected in the double-pass preamplifier for filtering. After the fiber laser preamplifier, a fiber laser main amplifier is connected. A single-mode fiber is added between the preamplifier and the main amplifier to broaden the pulse in the time domain. The 1μm high-power narrow-spectrum tunable picosecond laser output is achieved in the fiber laser main amplifier.
[0027] One of the aforementioned 1μm high-power narrow-spectrum tunable picosecond lasers is used as the pump light for the fiber optical parametric oscillator. The 1μm pump light is coupled into the photonic crystal fiber, and idler light is generated through a four-wave mixing process. The end of the photonic crystal fiber is treated with a 0-degree angle, resulting in 4% end-face reflection. Therefore, the idler light reaches the dichroic mirror after end-face reflection and is coupled into the single-mode fiber by reflection from the dichroic mirror. After passing through the single-mode fiber, the idler light is output from the collimator, reflected by the mirror on the shift stage, and recoupled into the single-mode fiber and back into the photonic crystal fiber. The mirror on the shift stage and the 0-degree end-face reflection of the fiber crystal fiber constitute the two end faces of the linear cavity of the fiber optical parametric oscillator.
[0028] By adjusting the displacement stage, the cavity length of the fiber optic parametric oscillator can be finely tuned, and the different spectral components of the idler light can be controlled to coincide with the pump light in time and space. This changes the oscillation wavelength of the fiber optic parametric resonator. Combined with tuning the center wavelength of the 1μm pump light, the output wavelength of the fiber optic parametric oscillator can be tuned.
[0029] The contents not described in detail in this specification are prior art known to those skilled in the art. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning, characterized in that: The system includes an embedded integrated control platform, which coordinates and controls a mode-locked laser seed source, a narrow-spectrum high-power tunable pump source, and a fiber optic parametric resonator. The mode-locked laser seed source uses a mode-locked laser oscillator as the seed source. A tunable spectral filter and a laser amplifier are set after the mode-locked laser seed source. The tunable spectral filter can also be set in the resonator of the mode-locked laser oscillator. A laser amplifier is set after the mode-locked laser oscillator to obtain a narrow-spectrum high-power tunable pulsed laser. The narrow-spectrum high-power tunable pulsed laser serves as the narrow-spectrum high-power tunable pump source. The mode-locked laser seed source is connected to a coupler, which is connected to two circulators. Port 2 of both circulators is connected to an acousto-optic tunable filter, and the acousto-optic tunable filter is connected to a preamplifier. The preamplifier is connected to a fiber optic mirror. Port 3 of both circulators is connected to a single-mode fiber, and the two single-mode fibers are connected to a main amplifier. After collimation, the main amplifier is followed by a dichroic mirror, a half-glass slide, and an isolator. After one of the isolators, a half-glass slide and a dichroic mirror are followed in sequence. The dichroic mirror is followed by a half-glass slide, a mirror, a collimator, a single-mode fiber, a collimator, and a mirror. At the same time, the dichroic mirror is also followed by a mirror, a half-glass slide, a collimator, a photonic crystal fiber, a lens, and a dichroic mirror in sequence.
2. The picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning according to claim 1, characterized in that: The mode-locked laser seed source has a repetition frequency of ~40MHz and a spectral coverage range of 1035-1065nm.
3. The picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning of claim 1, wherein: The mode-locked laser seed source is connected to an optical fiber coupler to split into two paths. The splitting ratio of the optical fiber coupler is 50 / 50. Both paths are connected to a fiber laser dual-pass preamplifier, and a tunable spectral filter is connected in the fiber laser dual-pass preamplifier.
4. The picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning of claim 1, wherein: The laser amplifier includes a fiber laser preamplifier and a fiber laser main amplifier. The fiber laser preamplifier is connected to the fiber laser main amplifier, and a single-mode fiber is added between the fiber laser preamplifier and the fiber laser main amplifier to broaden the pulse in the time domain.
5. The picosecond fiber optical parametric oscillator based on acousto-optic wavelength tuning of claim 1, wherein: The narrow-spectrum high-power tunable pump source couples 1μm pump light into a photonic crystal fiber, generates idler light through a four-wave mixing process, performs 0-degree processing at the tail of the photonic crystal fiber, and outputs the idler light from the collimator after passing through a single-mode fiber. It is then reflected by a mirror on the shift stage and recoupled into the single-mode fiber before returning to the photonic crystal fiber. The mirror on the shift stage and the 0-degree end face reflection of the fiber crystal fiber constitute the two end faces of the linear cavity of the fiber optical parametric oscillator.