A multiwavelength erbium-doped fiber laser

Abstract

The utility model discloses a kind of multi-wavelength erbium-doped fiber laser, belong to fiber laser technical field, comprising: pump light source, wavelength division multiplexer, erbium-doped gain fiber, first polarization controller, Mach-Zehnder interference filter, first coupler, fiber circulator, Sagnac filter, spectrometer;Pump light source is connected with the wavelength division multiplexer;Wavelength division multiplexer, erbium-doped gain fiber, fiber circulator, Mach-Zehnder interference filter, first polarization controller are sequentially connected to form a ring cavity structure;First coupler is connected with spectrometer, fiber circulator, Sagnac filter respectively.By the hybrid filter combination mode of MZI filter and Sagnac filter are connected in series combination, utilize fiber circulator connection, control the direction of light in ring cavity, and reasonably layout the two filtering structures in laser cavity, realize efficient optical path management and feedback control.

Description

Technical Field

[0001] This utility model relates to the field of fiber laser technology, and more specifically to a multi-wavelength erbium-doped fiber laser. Background Technology

[0002] With the rapid development of high-tech fields such as optical communication, fiber optic sensing, lidar, biological detection, and spectral analysis, the requirements for light source performance are becoming increasingly stringent. Erbium-doped fiber lasers (EDFLs) have emerged as a highly promising and important light source technology in these fields due to their significant advantages, including high stability, narrow linewidth, strong wavelength tunability, and flexible structure.

[0003] Currently, the realization of multi-wavelength erbium-doped fiber lasers mainly relies on various filtering structures. If the MZI and Sagnac structures are not properly arranged in the ring cavity, the filtering effect will be difficult to fully superimpose, reducing the stability and wavelength selectivity of the laser output. Secondly, hybrid filtering lasers often require multiple external devices, increasing assembly difficulty and insertion loss. Finally, a single filtering structure cannot simultaneously meet the requirements of wide control range and high stability.

[0004] Therefore, how to provide a multi-wavelength erbium-doped fiber laser that can effectively combine MZI interference structure and Sagnac interference structure and reasonably embed them into the laser cavity so that their filtering characteristics complement each other is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] In view of this, the present invention provides a multi-wavelength erbium-doped fiber laser. By combining a hybrid filtering method that connects an MZI filter and a Sagnac interference filter in series, and using a fiber optic circulator to control the direction of light within the circulator cavity, and by rationally arranging these two filtering structures within the laser cavity, efficient optical path management and feedback control are achieved. This enables stable output and fine tuning capabilities of multi-wavelength lasers, meeting the practical application needs of high-performance optical communication and sensing.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A multi-wavelength erbium-doped fiber laser includes: a pump source, a wavelength division multiplexer, an erbium-doped gain fiber, a first polarization controller, a Mach-Zehnder interferometer filter, a first coupler, a fiber circulator, a Sagnac filter, and a spectrometer;

[0008] The pump light source is connected to the wavelength division multiplexer;

[0009] The wavelength division multiplexer, the erbium-doped gain fiber, the fiber circulator, the Mach-Zehnder interferometer filter, and the first polarization controller are sequentially connected to form a ring cavity structure;

[0010] The first coupler is connected to the spectrometer, the fiber optic circulator, and the Sagnac filter, respectively.

[0011] Preferably, the Mach-Zehnder interferometer filter includes: an optical delay line, a second coupler, and a third coupler; the optical delay line, the second coupler, and the third coupler are connected in sequence to form a closed loop, the second coupler is connected to the first polarization controller, and the third coupler is connected to the fiber optic circulator.

[0012] Preferably, the Sagnac filter includes a polarization-maintaining fiber and a second polarization controller, the polarization-maintaining fiber and the second polarization controller forming a Sagnac loop.

[0013] Preferably, the pump source uses a laser diode to generate 976nm pump light.

[0014] Preferably, the fiber optic circulator is a three-port circulator.

[0015] As can be seen from the above technical solution, compared with the prior art, this utility model discloses a multi-wavelength erbium-doped fiber laser, which has the following beneficial effects:

[0016] 1. Optimized structural layout to improve the flexibility and stability of laser control: The MZI filter is placed in the main ring cavity, and the large free spectral range of the MZI filter achieves coarse wavelength filtering; the Sagnac filter is a fiber circulator placed in series with the MZI filter to provide narrowband filtering. The combination of the two achieves a composite filtering effect, which is beneficial to suppress mode competition and support stable multi-wavelength lasing and a wide control range.

[0017] 2. The fiber optic circulator adopts a three-port circulator structure to enhance feedback control and has a compact structure: the direction of light in the ring cavity is controlled by the fiber optic circulator, eliminating the need for an additional optical isolator to control the direction of the optical path, and it can connect an MZI filter and a Sagnac filter in series to achieve efficient optical path management and feedback control.

[0018] 3. Multi-wavelength output enhancement system applicability: The physical structure connecting the MZI filter and the Sagnac filter enables controllable multi-wavelength lasing, with good wavelength spacing control capability, making it suitable for high-throughput spectral systems or WDM communication. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a structural schematic diagram of the present invention.

[0021] Figure 2 The output result of a single-wavelength laser using the laser of this invention.

[0022] Figure 3 The result is a dual-wavelength laser output using the laser of this invention.

[0023] Figure 4 The output results of the three-wavelength laser using the laser of this invention are shown.

[0024] Figure 5 The output results of the four-wavelength laser using the laser of this invention are shown. Detailed Implementation

[0025] 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.

[0026] This invention discloses a multi-wavelength erbium-doped fiber laser, which achieves tunable and stable multi-wavelength laser output through optimized physical structure of hybrid filtering. The basic idea is to use an MZI filter and a Sagnac filter as the core wavelength selection module, connected by a fiber optic circulator, and to achieve flexible wavelength switching by adjusting the polarization controller. The laser uses a 976nm laser diode as the pump source and erbium-doped fiber as the gain medium to construct a ring cavity laser, achieving multi-wavelength laser output in the 1550-1570nm wavelength range.

[0027] This utility model discloses a multi-wavelength erbium-doped fiber laser, such as... Figure 1 As shown, it includes: a pump source 1, a wavelength division multiplexer 2, an erbium-doped gain fiber 3, a first polarization controller 10, a Mach-Zehnder interferometer filter, a first coupler 5, an optical fiber circulator 6, a Sagnac filter, and a spectrometer 4.

[0028] Pump light source 1 is connected to the input terminal of wavelength division multiplexer 2;

[0029] The output of wavelength division multiplexer 2, erbium-doped gain fiber 3, input a and isolation reflection c of fiber optic circulator 6, Mach-Zehnder interferometer filter, and first polarization controller 10 are connected in sequence to form a ring cavity structure.

[0030] The first coupler 5 is connected to the output terminal b of the spectrometer 4, the fiber optic circulator 6, and the Sagnac filter, respectively.

[0031] Specifically, the Mach-Zehnder interferometer filter includes: an optical delay line 8, a second coupler 9, and a third coupler 7; the two outputs of the optical delay line 8, the two outputs of the second coupler 9, and the two outputs of the third coupler 7 are connected in sequence to form a closed loop; the output of the second coupler 9 is connected to the first polarization controller 10; and the input of the third coupler 7 is connected to the isolation and reflection end c of the fiber optic circulator 6. This structure plays a role in the initial wavelength selection and is the core device for realizing wavelength modulation.

[0032] Furthermore, the Sagnac filter includes a polarization-maintaining fiber 11 and a second polarization controller 12. The polarization-maintaining fiber 11 and the second polarization controller 12 form a Sagnac loop, which, in conjunction with the second polarization controller 12, adjusts the polarization of the incident light to achieve narrowband filtering. This helps suppress side modes and improve spectral purity and stability. This structure primarily enhances the system's multi-wavelength output capability, narrows the laser linewidth, and improves laser output stability.

[0033] Furthermore, the pump source 1 uses a laser diode to generate 976nm pump light, which is coupled into the erbium-doped fiber via a wavelength division multiplexer 2 to provide gain in the 1550nm band.

[0034] In another embodiment, the fiber optic circulator 6 is a three-port circulator. The three-port circulator provides unidirectional guidance for the laser and connects to two interference filters to form a hybrid filtering structure. The laser outputs along the a→b direction, passes through a Sagnac filter, and then returns to the cavity via b→c, forming feedback. By introducing the circulator and connecting two interference filters, the direction of light transmission is controlled, improving optical feedback efficiency and reducing return loss.

[0035] The novel hybrid filtering structure proposed in this invention can achieve multi-wavelength control output from single wavelength to four wavelengths by adjusting the first polarization controller 10 and the second polarization controller 12. Figure 2 It outputs a single-wavelength laser at 1560.11nm. Figure 3 It outputs dual-wavelength lasers at 1559.8nm and 1565.6nm. Figure 4 It outputs laser light at three wavelengths: 1560.4nm, 1561.2nm, and 1567.0nm. Figure 5It outputs lasers at four wavelengths: 1561.6nm, 1562.4nm, 1563.3nm, and 1567.4nm. The signal-to-noise ratio is greater than 31dB for all wavelengths.

[0036] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0037] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-wavelength erbium-doped fiber laser, characterized in that, include: Pump source, wavelength division multiplexer, erbium-doped gain fiber, first polarization controller, Mach-Zehnder interferometer filter, first coupler, fiber optic circulator, Sagnac filter, spectrometer; The pump light source is connected to the wavelength division multiplexer; The wavelength division multiplexer, the erbium-doped gain fiber, the fiber circulator, the Mach-Zehnder interferometer filter, and the first polarization controller are sequentially connected to form a ring cavity structure; The first coupler is connected to the spectrometer, the fiber optic circulator, and the Sagnac filter, respectively.

2. The multi-wavelength erbium-doped fiber laser according to claim 1, characterized in that, The Mach-Zehnder interferometer filter includes an optical delay line, a second coupler, and a third coupler; the optical delay line, the second coupler, and the third coupler are connected in sequence to form a closed loop, the second coupler is connected to the first polarization controller, and the third coupler is connected to the fiber optic circulator.

3. A multi-wavelength erbium-doped fiber laser according to claim 1, characterized in that, The Sagnac filter includes a polarization-maintaining fiber and a second polarization controller, which together form a Sagnac loop.

4. A multi-wavelength erbium-doped fiber laser according to claim 1, characterized in that, The pump source uses a laser diode to generate 976nm pump light.

5. A multi-wavelength erbium-doped fiber laser according to claim 1, characterized in that, The fiber optic circulator is a three-port circulator.

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