Dual-wavelength light path structure for reducing ASE noise

Abstract

The utility model discloses a dual-wavelength optical path structure capable of reducing ASE noise, which belongs to the field of aerospace optical amplifiers and is used for reducing the ASE of light output by an optical amplifier, improving the OSNR and improving the sensitivity of a system. The device mainly comprises a jumper IN, a secondary amplification light path and an optical fiber ER, the jumper IN is connected with a wavelength division multiplexer M1, the wavelength division multiplexer M1 is connected with the input end of a wavelength division multiplexer W2 and the input end of a wavelength division multiplexer W5, the wavelength division multiplexer M1 screens two kinds of light with different wavelengths to form two light paths, and the two light paths are connected with the optical fiber ER. The output end of the wavelength division multiplexer W2 and the output end of the wavelength division multiplexer W5 are sequentially connected with the optical fiber ER and the filters BP, the output ends of the two filters BP are connected with the wavelength division multiplexer M2, the two optical paths are converged on the wavelength division multiplexer M2, and the wavelength division multiplexer M2 is connected with the secondary amplification optical path. The utility model is mainly used for spaceflight optical amplifiers.

Description

Technical Field

[0001] This utility model relates to the field of aerospace optical amplifiers, and more specifically, to a dual-wavelength optical path structure for reducing ASE noise. Background Technology

[0002] Space laser communication is a communication method that uses laser beams as carriers to transmit images, voice, and signals in space. Compared with traditional microwave communication, laser communication has advantages such as high transmission rate, large communication capacity, strong resistance to electromagnetic interference, and high security. Furthermore, its communication terminals are small in size, have low power consumption, and are highly practical. As a crucial component in space laser communication, the optical amplifier can amplify weak input light signals to a higher power level, thereby improving signal transmission distance and quality. This is critical for addressing signal attenuation issues in long-distance fiber optic transmission and optical communication systems.

[0003] In traditional dual-wavelength optical amplifiers, there are currently two solutions:

[0004] 1. Without using a filter in the optical path, when the signal light is amplified, all light in the 1530nm-1570nm band will be amplified. The ASE of the output light in all bands within this range is high, resulting in a low OSNR of the signal light and affecting the system sensitivity.

[0005] 2. The optical amplifier uses filters with two seed wavelengths connected in parallel in the optical path. This amplifies wavelengths near the two seed wavelengths while reducing the ASE (Acoustic Emission System) in other wavelength bands. This approach reduces the power proportion of ASE in the signal light output, improving system sensitivity. However, when amplifying the signal light, the presence of the filter also partially amplifies the wavelengths near the other wavelength, resulting in a higher ASE in that band. For systems that cannot distinguish between the two wavelengths, this approach has no difference in OSNR (Optical System Noise Ratio) compared to the first approach, and there is no improvement in system sensitivity. Utility Model Content

[0006] The purpose of this invention is to provide a dual-wavelength optical path structure that reduces ASE noise. After the jumper IN, the two wavelengths of light are split by a wavelength division multiplexer. After splitting, two first-stage amplification optical paths are used to amplify the two signal lights respectively. A single-wavelength filter BP is added at the output of the first-stage amplification to filter out all ASE except for the signal light. The filtered signal light passes through a wavelength division multiplexer M2 and enters the second-stage amplification optical path, ensuring that the ASE entering the second-stage optical path is low enough to reduce the ASE of the output optical amplifier, improve OSNR, and enhance system sensitivity.

[0007] This utility model is achieved through the following technical solution:

[0008] A dual-wavelength optical path structure for reducing ASE noise includes a jumper IN, a secondary amplification optical path, and an optical fiber ER. The jumper IN is connected to a wavelength division multiplexer M1. The wavelength division multiplexer M1 is connected to the input terminals of wavelength division multiplexers W2 and W5, respectively. The wavelength division multiplexer M1 filters two different wavelengths of light to form two optical paths. The output terminals of wavelength division multiplexers W2 and W5 are connected to the optical fiber ER and a filter BP in sequence. The output terminals of both filters BP are connected to wavelength division multiplexer M2. The two optical paths converge at wavelength division multiplexer M2, which is connected to the secondary amplification optical path.

[0009] Furthermore, it also includes a pump LM2, the output of which is connected to the input of the wavelength division multiplexer W2.

[0010] Furthermore, the wavelength division multiplexers M1, W2, W5, and M2 are all filter-type wavelength division multiplexers.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. After the jumper IN, a wavelength division multiplexer splits the two wavelengths of light. After splitting, two first-stage amplification optical paths are used to amplify the two signal lights respectively. A single-wavelength filter BP is added at the output of the first-stage amplification to filter out all ASE except for the signal light. The filtered signal light passes through the wavelength division multiplexer M2 and enters the second-stage amplification optical path. It is ensured that the ASE entering the second-stage optical path is low enough to reduce the ASE of the output optical amplifier, improve OSNR, and enhance system sensitivity.

[0013] 2. With improved sensitivity, it can replace two single-wavelength optical amplifiers in a satellite optical communication system, reducing satellite size and weight, and lowering equipment and launch costs. Attached Figure Description

[0014] Figure 1 This is the optical path schematic diagram of this utility model. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings.

[0016] like Figure 1As shown in Example 1, a dual-wavelength optical path structure for reducing ASE noise includes a jumper IN, a secondary amplification optical path (existing technology), and an optical fiber ER. The jumper IN is connected to a wavelength division multiplexer M1. The wavelength division multiplexer M1 is connected to the input terminals of wavelength division multiplexers W2 and W5, respectively. The wavelength division multiplexer M1 filters two different wavelengths of light to form two optical paths. The output terminals of wavelength division multiplexers W2 and W5 are connected to the optical fiber ER and filter BP in sequence. The optical fiber ER pre-amplifies the optical path, amplifying the signal light from a weak signal to above the working threshold of the secondary amplification optical path. The ASE output of the primary amplification optical path determines the ASE output of the secondary amplification optical path. Therefore, reducing the ASE of the primary amplification optical path can solve the problem of excessively high ASE output of the optical amplifier. The output terminals of the two filters BP are connected to the wavelength division multiplexer M2. The two optical paths converge at the wavelength division multiplexer M2, which is connected to the secondary amplification optical path.

[0017] When the primary amplification optical path amplifies the signal light, it simultaneously generates a high ASE (albedo) in the 1530nm-1570nm wavelength band. This ASE is also amplified by the secondary optical path. Traditional solutions add a dual-wavelength filter at the output of the primary amplification optical path, which can effectively reduce ASE except in the filtered wavelength band, but ASE near the filter wavelength cannot be filtered out. This invention uses a wavelength division multiplexer after the jumper IN (signal light input optical path) to split the two wavelengths of light. After splitting, two primary amplification optical paths are used to amplify the two signal lights respectively. A single-wavelength filter BP is added at the output of the primary amplification to filter out all ASE except for the signal light. The filtered signal light then passes through a wavelength division multiplexer M2 before entering the secondary amplification optical path, ensuring that the ASE entering the secondary optical path is sufficiently low.

[0018] Example 2: A dual-wavelength optical path structure for reducing ASE noise, further comprising a pump LM2, the output of which is connected to the input of a wavelength division multiplexer W2; the wavelength division multiplexers M1, W2, W5, and M2 are all filter-type wavelength division multiplexers, W2 is a 980 / 1550 filter-type wavelength division multiplexer, the pump LM2 is a 980nm pump, the output of the pump LM2 is connected to the 980nm input of the wavelength division multiplexer W2, the signal light passes through the 1550nm port of the wavelength division multiplexer W2 and is combined with the 980nm pump light source before entering the first-stage optical path (ER fiber amplification), the rest is the same as in Example 1.

[0019] Working principle:

[0020] 1) The signal light enters the corresponding optical path after passing through the wavelength division multiplexer M1 from the IN jumper. The two different wavelengths of light are filtered and then output from the designated channel.

[0021] 2) After the signal light enters the primary optical path, it is combined with the pump light through the wavelength division multiplexer W2 and then amplified through the ER fiber. At this time, the 980nm pump LM2 of this path is turned on, while the 980nm pump LM2 of the other path is turned off.

[0022] 3) After the amplified signal light passes through the first single-wavelength filter BP, all ASE except the signal light is filtered out.

[0023] 4) Since the 980nm pump LM2 of the other path is not turned on, the noise light of other wavelengths after passing through the second single-wavelength filter BP is extremely weak, and the noise source cannot be amplified when it enters the secondary amplification optical path.

[0024] 5) After being filtered by the first single-wavelength filter BP, the signal light passes through the wavelength division multiplexer M2 and enters the second-stage amplification optical path, becoming the only amplifiable light. This wavelength of light, after being amplified by the second-stage optical path, becomes the only usable signal light.

[0025] 6) Similarly, when it is necessary to amplify the signal light of the second wavelength, the amplification can be achieved by turning on the 980nm pump LM2 of the corresponding path.

Claims

1. A dual-wavelength optical path structure for reducing ASE noise, comprising a jumper IN, a two-stage amplification optical path and an optical fiber ER, characterized in that: The jumper IN is connected with a wavelength division multiplexer M1, the wavelength division multiplexer M1 is connected with an input end of a wavelength division multiplexer W2 and an input end of a wavelength division multiplexer W5 respectively, the wavelength division multiplexer M1 filters two different wavelengths of light to form two optical paths, an output end of the wavelength division multiplexer W2 and an output end of the wavelength division multiplexer W5 are sequentially connected with an optical fiber ER and a filter BP, output ends of two filters BP are connected with a wavelength division multiplexer M2, the two optical paths converge at the wavelength division multiplexer M2, and the wavelength division multiplexer M2 is connected with a secondary amplification optical path.

2. The dual-wavelength optical path structure for reducing ASE noise according to claim 1, characterized by: A pump LM2 is further included, and an output end of the pump LM2 is connected with an input end of the wavelength division multiplexer W2.

3. The dual-wavelength optical path structure for reducing ASE noise according to claim 1, characterized by: The wavelength division multiplexer M1, the wavelength division multiplexer W2, the wavelength division multiplexer W5 and the wavelength division multiplexer M2 are all filter type wavelength division multiplexers.

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