ASE light source spectrum pattern and average wavelength optimization adjusting device and optimization method

Abstract

The invention discloses an ASE light source spectrum pattern and average wavelength optimization adjusting device and an optimization method. The ASE light source spectrum pattern and average wavelength optimization adjusting device comprises a small circle / bevel angle, an adjustable attenuator, a wavelength division multiplexer, an isolator, an optical splitter and a grating which are sequentially arranged from a light input end to a light output end. The optical input end and the optical output end of the adjustable attenuator are communicated with erbium-doped optical fibers; the wavelength division multiplexer is connected in parallel with a pump laser; and the optical splitter is also provided with a coaxial detector. The adjustable optical fiber attenuator is added into a traditional ASE light source, the effective length of the erbium-doped optical fiber in the ASE light source can be rapidly adjusted on line, and therefore optimization of the ASE light source spectrum pattern and the average wavelength stability is efficiently and rapidly completed.

Description

Technical Field

[0001] The present invention relates to the technical field of light source optimization, and in particular to an ASE light source spectrum type and average wavelength optimization and adjustment device and an optimization method. Background Art

[0002] The light source is the source of the fiber optic gyroscope signal, and its performance will directly affect the performance of the fiber optic gyroscope. Studies have shown that a fiber optic light source with a reasonable structure can have multiple excellent characteristics such as high power, wide bandwidth and good wavelength stability. It can reduce and eliminate the coherence error and noise caused by Rayleigh backscattering, Kerr effect, polarization cross coupling, etc., and improve the accuracy of the fiber optic gyroscope and the stability of the scale factor. The core components of the erbium-doped fiber light source are pump lasers, erbium-doped fibers, and wavelength division multiplexers. Among them, erbium-doped fiber is the "place" in the light source where spontaneous emission of large radiation is generated, and its characteristics will directly affect the performance of the ASE light source. Therefore, it is particularly important to ensure the spectrum type and average wavelength stability of the fiber optic gyroscope ASE light source. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to provide an ASE light source spectrum type and average wavelength optimization adjustment device and optimization method, which adds an adjustable fiber attenuator to the traditional ASE light source, and can quickly adjust the effective length of the erbium-doped fiber in the ASE light source online, thereby efficiently and quickly completing the optimization of the ASE light source spectrum type and average wavelength stability.

[0004] In order to solve the above problems, the present invention provides an ASE light source spectrum type and average wavelength optimization and adjustment device, including a small circle / bevel, an adjustable attenuator, a wavelength division multiplexer, an isolator, a splitter and a grating arranged in sequence from the optical input end to the optical output end; the optical input end and the optical output end of the adjustable attenuator are both connected to erbium-doped optical fiber; a pump laser is connected in parallel to the wavelength division multiplexer; and a coaxial detector is also provided on the splitter.

[0005] An optimization method for an ASE light source spectrum type and average wavelength optimization adjustment device, comprising:

[0006] S1. Fusion assemble the optical devices, fuse the adjustable attenuator to the midpoint attachment of the erbium-doped optical fiber, and adjust the attenuation value of the adjustable attenuator to 50% of the maximum attenuation value;

[0007] S2. Place the ASE light source in a temperature test chamber, and connect the light source output pigtail after the grating to the spectrometer. After measuring the spectral parameters, run the temperature cycle program in the temperature chamber to measure the average wavelength stability of the ASE light source;

[0008] S3. If the performance of the tested ASE light source cannot meet the use requirements, adjust the attenuation value of the attenuator according to the out-of-tolerance situation of the spectrum type and wavelength stability;

[0009] S4. Repeat the operations of S2 and S3 until the performance of the ASE light source meets the usage requirements.

[0010] Preferably, in each optical device fusion-assembled in S1, the reserved length of the erbium-doped optical fiber is 30% longer than the length of the erbium-doped optical fiber of the ASE light source with the same output power.

[0011] The advantages of the present invention compared with the prior art are:

[0012] The purpose of the present invention is to design an ASE light source spectrum type and average wavelength optimization adjustment device and optimization method. The theoretical basis is that the length of the erbium fiber directly affects the spectrum type and average wavelength stability of the ASE light source. Optimizing the length of the erbium fiber can improve the performance of the ASE light source. Compared with the traditional ASE light source solution, the present invention adds an adjustable attenuator to the erbium-doped fiber. The transmission distance of the pump light in the erbium-doped fiber can be adjusted by adjusting the attenuation value of the attenuator, which is equivalent to adjusting the length of the erbium-doped fiber, thereby realizing rapid adjustment of the ASE light source spectrum type and average wavelength stability.

[0013] The ASE light source spectrum and average wavelength optimization and adjustment device and optimization method of the present invention have the following advantages over the traditional ASE light source: when the average wavelength stability and spectrum of the traditional ASE light source solution cannot meet the use requirements, if the ASE light source performance is optimized by optimizing the length of the erbium-doped optical fiber, it is necessary to interrupt the melting point between the erbium-doped optical fiber and the wavelength division multiplexer, replace a longer erbium fiber or shorten the erbium fiber and fuse it with the wavelength division multiplexer again. If the use requirements are still not met after retesting, the above operation must be repeated. The process of repeated welding is very cumbersome and inefficient, and there is also a risk of damaging the light path of the light source during the operation. In the present invention, an adjustable attenuator is added in the middle of the erbium fiber, and the performance of the ASE light source can be improved by adjusting the attenuation value, thereby avoiding repeated welding of the light path, and having the characteristics of simplicity, convenience and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a schematic diagram of the optical path structure of the adjustment device in the present invention;

[0016] Figure 2The spectrum curve diagram of the natural spectrum of the light source under different erbium fiber lengths and driving currents in the present invention; (a) erbium fiber length 3m (b) erbium fiber length 4m (c) erbium fiber length 5m (d) erbium fiber length 6m (e) erbium fiber length 8m (f) erbium fiber length 10m;

[0017] Figure 3 It is a curve diagram showing the relationship between the 1560nm peak average wavelength stability and the erbium fiber length in the present invention;

[0018] In the figure: 1-grating, 2-coaxial detector, 3-splitter, 4-isolator, 5-pump laser, 6-wavelength division multiplexer, 7-erbium-doped fiber, 8-adjustable attenuator, 9-small circle / bevel. DETAILED DESCRIPTION

[0019] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0020] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0022] In order to solve the above problems, the present invention provides an ASE light source spectrum and average wavelength optimization and adjustment device, including a small circle / bevel 9, an adjustable attenuator 8, a wavelength division multiplexer 6, an isolator 4, a splitter 3 and a grating 1 arranged in sequence from the optical input end to the optical output end; the optical input end and the optical output end of the adjustable attenuator are both connected to an erbium-doped optical fiber 7; a pump laser 5 is connected in parallel to the wavelength division multiplexer; and a coaxial detector 2 is also provided on the splitter.

[0023] An optimization method for an ASE light source spectrum type and average wavelength optimization adjustment device, comprising:

[0024] S1. Fusion assemble the optical devices, fuse the adjustable attenuator to the midpoint attachment of the erbium-doped optical fiber, and adjust the attenuation value of the adjustable attenuator to 50% of the maximum attenuation value;

[0025] S2. Place the ASE light source in a temperature test chamber, and connect the light source output pigtail after the grating to the spectrometer. After measuring the spectral parameters, run the temperature cycle program in the temperature chamber to measure the average wavelength stability of the ASE light source;

[0026] S3. If the performance of the tested ASE light source cannot meet the use requirements, adjust the attenuation value of the attenuator according to the out-of-tolerance situation of the spectrum type and wavelength stability;

[0027] S4. Repeat the operations of S2 and S3 until the performance of the ASE light source meets the usage requirements.

[0028] Preferably, in each optical device fusion-assembled in S1, the reserved length of the erbium-doped optical fiber is 30% longer than the length of the erbium-doped optical fiber of the ASE light source with the same output power.

[0029] In order to more clearly illustrate the specific implementation mode of the present invention, an embodiment is provided below:

[0030] The present invention provides an ASE light source spectrum type and average wavelength optimization and adjustment device and optimization method. Applicable ASE light source solutions include but are not limited to single-pass backward ASE light source solutions; applicable ASE light source spectrum types include but are not limited to 1560nm band Gaussian spectrum; applicable adjustable optical fiber attenuators include but are not limited to mechanical optical attenuators.

[0031] The present invention provides Figure 2 The spectral curves of the natural spectrum of the light source under different erbium fiber lengths and driving currents are shown, where for a group of curves in each figure, the peak wavelengths are from (a) to (f) for driving currents of 200mA, 180mA, 160mA, 140mA, 120mA, 100mA, and 80mA, respectively. It can be seen that the spectrum of the light source under different driving currents will be affected by the length of the erbium-doped fiber.

[0032] The change of the average wavelength of the light source is mainly affected by the external environment temperature. The temperature stability of the average wavelength is usually expressed in units of ppm or ppm / ℃. In erbium-doped fiber light sources, the change of the average wavelength has the following four sources:

[0033]

[0034] The first term in the above equation is determined by the interaction between absorption and radiation in the erbium-doped fiber light source and the sign and amplitude of the spectrum drift with temperature in this process. It reflects the intrinsic rate of change of the radiation wavelength of the erbium-doped fiber with temperature, which is related to the characteristics of the fiber itself. The second term is the pump wavelength λ PThe effect of temperature changes on the radiation wavelength. When using a pump laser for pumping, the laser diode in the pump laser has a strong temperature dependence. The temperature changes inside and outside will cause the pump wavelength to change, thereby changing the pump absorption rate. The population inversion along the erbium-doped fiber is a function of the pump absorption rate, which will make the average wavelength of the spectrum However, since the pump lasers currently used usually use fiber Bragg grating wavelength stabilization technology, and at the same time, the peak of the pump absorption band is selected as the pump, the instability of the light source output caused by the pump wavelength disturbance can be greatly reduced. The third item is that temperature changes lead to changes in pump power, which in turn leads to the deformation of the spectrum, thus affecting the average wavelength. This is the result of thermal effects and gain saturation effects. The fourth term is related to the optical feedback of the fiber optic gyroscope. The optical feedback of the gyroscope changes with temperature, affecting the average wavelength. The above four parameters are not completely linearly correlated, but there is a high-order temperature correlation. Experiments have found that the most important factor affecting the average wavelength stability of the light source is the length of the erbium fiber, that is, the contribution of the average wavelength instability mainly comes from the inherent thermal coefficient of the erbium fiber. Taking the 1560nm peak of a 10mW output light source as an example, a 12-meter-long erbium fiber is selected and cut meter by meter to conduct an average wavelength temperature stability experiment. At this time, all the scattered optical paths are placed in an incubator and subjected to a temperature cycle of -40℃ to 60℃. The spectrometer is used to intercept simulated bandpass filtering, and the extreme value difference of the average wavelength near the main peak is measured. The results are as follows. Figure 3 As shown, it can be seen that the length of the erbium fiber has a very obvious effect on the average wavelength stability of the ASE light source.

[0035] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. An ASE light source spectrum and average wavelength optimization and adjustment device, characterized in that: The invention comprises a small circle / bevel, an adjustable attenuator, a wavelength division multiplexer, an isolator, a splitter and a grating which are arranged in sequence from the optical input end to the optical output end; the optical input end and the optical output end of the adjustable attenuator are both connected with erbium-doped optical fiber; a pump laser is connected in parallel to the wavelength division multiplexer; and a coaxial detector is also arranged on the splitter.

2. An optimization method for the ASE light source spectrum and average wavelength optimization adjustment device as claimed in claim 1, characterized in that: S1. Fusion assemble the optical devices, fuse the adjustable attenuator to the midpoint attachment of the erbium-doped optical fiber, and adjust the attenuation value of the adjustable attenuator to 50% of the maximum attenuation value; S2. Place the ASE light source in a temperature test chamber, and connect the light source output pigtail after the grating to the spectrometer. After measuring the spectral parameters, run the temperature cycle program in the temperature chamber to measure the average wavelength stability of the ASE light source; S3. If the performance of the tested ASE light source cannot meet the use requirements, adjust the attenuation value of the attenuator according to the out-of-tolerance situation of the spectrum type and wavelength stability; S4. Repeat the operations of S2 and S3 until the performance of the ASE light source meets the usage requirements.

3. The optimization method of the ASE light source spectrum and average wavelength optimization adjustment device according to claim 2, characterized in that: In each optical device fused and assembled in S1, the reserved length of the erbium-doped optical fiber is 30% longer than the length of the erbium-doped optical fiber of the ASE light source with the same output power.

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