A dual-wavelength optical signal receiving method for a 50G ONU optical device
By employing reflective, tilt, and 0-degree filters arranged at specific angles in the 50G ONU optical device, the problem of high production cost in the prior art is solved, and flexible adaptation and high isolation for wavelengths of 1342±2nm and 1366±2nm are achieved, meeting the compatibility requirements of communication links.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU RONGBO COMM TECH CO LTD
- Filing Date
- 2026-02-27
- Publication Date
- 2026-05-26
AI Technical Summary
Existing 50G ONU optical devices have high production costs due to the use of 0-degree dual bandpass filters, which cannot meet the requirements for flexible adaptation and communication link compatibility between the ONU and OLT ends.
A dual-wavelength optical signal receiving method is adopted, consisting of a 37-degree reflective filter, an 8-degree tilted filter, and a horizontally arranged 0-degree filter, to replace the existing combination of a 45-degree filter and a 0-degree dual bandpass filter. The method achieves effective reception and filtering of optical signals through specific angle and pass/stopband design.
It reduces production costs while achieving flexible adaptation and high isolation for both 1342±2nm and 1366±2nm wavelengths, ensuring the compatibility and flexibility of the communication link.
Smart Images
Figure CN122092980A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical communication technology, and specifically to a dual-wavelength optical signal receiving method for a 50G ONU optical device. Background Technology
[0002] Currently, conventional 50G ONU optical devices generally adopt a single-transmit, single-receive duplex structure. This means the transmitter (TX) outputs a 1286±2nm wavelength optical signal, and the receiver (RX) receives a 1342±2nm wavelength optical signal. This duplex optical device enables bidirectional communication with the OLT, meeting basic 50G high-speed communication requirements. However, in many commercial scenarios, the OLT requires multi-wavelength signal output. To achieve flexible adaptation between the ONU and OLT, an additional 1366±2nm wavelength receiving function needs to be added to the ONU. This function receives the 1366±2nm optical signal emitted by the OLT, enabling flexible reception of both 1342±2nm and 1366±2nm communication wavelengths and ensuring compatibility and flexibility of the communication link in different commercial scenarios.
[0003] To achieve dual-wavelength signal reception, existing technologies have proposed designs using 0-degree dual bandpass filters, such as... Figure 4 , 5 As shown, in this 0-degree dual-bandpass filter, the passband is defined as having a transmission loss of less than 1dB, with wavelengths ranging from 1340 to 1344 nm and 1364 to 1368 nm; the stopband is defined as having a transmission loss greater than or equal to 20dB, with wavelengths ranging from 1260 to 1335 nm, 1349 to 1359 nm, and 1373 to 1500 nm. The core function of this dual-bandpass filter is to simultaneously allow optical signals of 1342±2 nm and 1366±2 nm to pass through, while isolating other irrelevant wavelengths. This achieves wavelength division and filtering between the transmitter and receiver, ensuring the accuracy of optical signal transmission.
[0004] Furthermore, such as Figure 4 As shown, the 1286±2nm wavelength optical signal output from the transmitter (TX) is almost completely transmitted through a 45-degree filter and then transmitted to the COM / OUT port (this port is the interface with the external optical fiber). The external dual-wavelength optical signals 1342±2nm and 1366±2nm are incident on the 45-degree filter through the COM / OUT port, where total internal reflection is achieved, and the optical signals are reflected and transmitted to the 0-degree dual bandpass filter. After being filtered by the dual bandpass filtering function of the 0-degree filter, the two independent optical signals RX 1342±2nm and 1366±2nm can be received. Summary of the Invention
[0005] To address the shortcomings and defects of the existing technology, this invention proposes a dual-wavelength optical signal receiving method for 50G ONU optical devices. The method aims to replace the existing receiving optical path that combines a 45-degree filter with a 0-degree dual bandpass filter by employing a 37-degree reflective filter, an 8-degree tilt filter, and a horizontally arranged 0-degree filter to form a dual-wavelength optical signal receiving optical path. This solves the problem of high production costs associated with the use of 0-degree dual bandpass filters in existing single-transmitter dual-receiver 50G ONU optical devices.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A dual-wavelength optical signal receiving method for a 50G ONU optical device includes sequentially arranging a 0-degree filter, a tilt filter, and a reflection filter in the receiving optical path of the optical receiving module. The received optical signal is processed sequentially by the reflection filter, the tilt filter, and the 0-degree filter to obtain optical signals with wavelengths in the ranges of 1342±2nm and 1366±2nm, which then enter the optical receiving module. Each filter should meet the following technical requirements: S1. The reflective filter is fixed at an angle of 37 degrees to the vertical axis on the lower left side of the optical receiving module to satisfy the total reflection of the received optical signal and to satisfy the requirement that the total reflected optical signal be incident downwards onto the inclined filter at an angle of 8 degrees. S2. The tilted filter has a passband with a wavelength range of 1350~1360nm and a stopband with wavelength ranges of 1300~1344nm and 1364~1400nm; the tilted filter is fixed below the optical receiving module at an angle of 8 degrees to the horizontal plane, so as to ensure that all optical signals with wavelength ranges of 1350~1360nm are transmitted and that all optical signals with wavelength ranges of 1300~1344nm and 1364~1400nm are reflected vertically upwards; The S3.0 degree filter has a passband with a wavelength range of 1340~1368nm and a stopband with wavelength ranges of 1300~1335nm and 1373~1400nm. The 0 degree filter is horizontally fixed directly below the optical receiving module to ensure that the optical signal totally reflected by the tilted filter is incident on the 0 degree filter at a 0 degree incident angle, and to ensure that the optical signals in the two wavelength ranges of 1342±2nm and 1366±2nm are transmitted to the optical receiving module.
[0007] An RX converging lens is also fixed in the receiving optical path. The RX converging lens is located between the 0-degree filter and the tilted filter, and is close to the 0-degree filter.
[0008] The receiving optical path is also equipped with an SC adapter for receiving optical signals. The optical signals received by the SC adapter are processed sequentially by a reflection filter, a tilt filter, an RX converging lens, and a 0-degree filter before entering the optical receiving module.
[0009] The reflective filter and the SC adapter are both arranged on the same horizontal line, with the 0-degree filter and the tilted filter located above and below the reflective filter, respectively.
[0010] The optical receiving module, 0-degree filter, RX converging lens, tilt filter, reflection filter, and SC adapter are all fixed together as a whole by the housing.
[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: The key innovation of this invention lies in the sequential placement of a 0-degree filter, a tilt filter, and a reflection filter in the receiving optical path of the optical receiving module. The reflection filter and the tilt filter are combined at 37 degrees and 8 degrees, respectively, totaling 45 degrees. This ensures that the received optical signal undergoes a 90-degree deflection after passing through these two filters before reaching the 0-degree filter, thereby guaranteeing effective reception and filtering of the optical signal. The tilt filter uses an 8-degree incident angle, resulting in a smaller incident angle for the optical signal, which is beneficial for achieving an isolation of over 30dB for wavelengths within the stopband. It should be noted that a tilt filter angle greater than 8 degrees would lead to a decrease in isolation; conversely, a tilt filter angle less than 8 degrees would result in an excessively large placement distance between the reflection filter and the tilt filter, increasing the size of the optical device and hindering connection to hardware devices such as optical modems. Therefore, the reflection filter angle is designed to be 37 degrees, ensuring both a stable optical device size and high isolation. In addition, the 0-degree filter is fixed horizontally directly below the optical receiving module. Since the received optical signal is reflected by the 37-degree filter and vertically reflected upward by the 8-degree filter, the light is already collinear with the center of the optical receiving module. At this time, the use of the 0-degree filter can make the optical signal incident vertically, and finally achieve effective reception of optical signals in two wavelength ranges.
[0012] In summary, compared to the existing technology that uses a combination of a 45-degree filter and a 0-degree dual bandpass filter in the receiving optical path, this invention uses three filters with specific pass and stop band coating designs, arranged at a specific angle to form the receiving optical path. This not only enables flexible adaptation to receive two wavelengths, 1342±2nm and 1366±2nm, but also effectively reduces production costs. Attached Figure Description
[0013] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is the passband and stopband spectrum of the tilted filter in this invention; Figure 3 This is the passband and stopband spectrum of the 0-degree filter in this invention; Figure 4 Optical path diagram of an existing conventional 50G ONU; Figure 5 This is the dual bandpass spectrum of an existing 0-degree dual bandpass filter.
[0014] The following are labeled in the diagram: 1. Housing, 2. Optical receiver module, 3. Receiver optical path, 4. SC adapter, 5. RX converging lens, 6. Reflection filter, 7. Tilt filter, 8. 0-degree filter. Detailed Implementation
[0015] The present invention will be further described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
[0016] like Figure 1 As shown, this invention provides a dual-wavelength optical signal receiving method for a 50G ONU optical device. This method includes sequentially arranging a 0-degree filter 8, a tilt filter 7, and a reflection filter 6 on the receiving optical path 3 of the optical receiving module 2. This allows the received optical signal to be processed sequentially by the reflection filter 6, the tilt filter 7, and the 0-degree filter 8, thereby obtaining optical signals with wavelengths in the ranges of 1342±2nm and 1366±2nm, which then enter the optical receiving module 2. Crucially, each filter should meet the following technical requirements: like Figure 1 As shown, S1. The reflective filter 6 is fixed at an angle of 37 degrees to the vertical axis on the lower left side of the optical receiving module 2 to satisfy the total internal reflection of the received optical signal and to satisfy the total internal reflection of the optical signal to be incident on the inclined filter 7 at an angle of 8 degrees.
[0017] like Figure 1 , 2 As shown, S2. The tilted filter 7 has a passband with a wavelength range of 1350~1360nm and a stopband with wavelength ranges of 1300~1344nm and 1364~1400nm. The transmission loss of the passband is less than 1dB, and the isolation of the stopband is at least 30dB. The tilted filter 7 is fixed below the optical receiving module 2 at an angle of 8 degrees to the horizontal plane, and is also located below the reflective filter 6. This is to ensure that all optical signals with wavelengths in the range of 1350~1360nm are transmitted, and that all optical signals with wavelengths in the ranges of 1300~1344nm and 1364~1400nm are reflected vertically upwards. Through this tilted filter 7, the received optical signal can be effectively filtered and reflected between the reflective filter 6 and the 0-degree filter 8, and the reflected optical signal is perpendicularly incident on the 0-degree filter 8.
[0018] like Figure 1 , 3 As shown, the S3.0-degree filter 8 has a passband with a wavelength range of 1340~1368nm and a stopband with wavelength ranges of 1300~1335nm and 1373~1400nm. The transmission loss of the passband is less than 1dB, and the isolation of the stopband is at least 30dB. The 0-degree filter 8 is horizontally fixed directly below the optical receiving module 2 and above the reflective filter 6. This allows the optical signal totally reflected by the tilted filter 7 to be incident on the 0-degree filter 8 at a 0-degree angle of incidence, and also allows optical signals in the two wavelength ranges of 1342±2nm and 1366±2nm to be transmitted to the optical receiving module 2. Through this 0-degree filter 8, the effective reception of the required dual-band optical signals can be achieved.
[0019] The reflective filter 6, tilted filter 7, and 0-degree filter 8 used in this invention have been shown in actual manufacturing to have a manufacturing cost of only about 20 RMB per filter. Compared with existing dual-band filters that cost hundreds of US dollars, this invention can effectively reduce production costs and has better practicality while flexibly receiving optical signals of two wavelengths, 1342±2nm and 1366±2nm.
[0020] like Figure 1 As shown, in order to improve the reception quality of optical signals, an RX converging lens 5 is further fixed on the receiving optical path 3. The RX converging lens 5 is located between the 0-degree filter 8 and the tilted filter 7, and is close to the 0-degree filter, which can make the intensity of the optical signal reflected by the tilted filter 7 higher.
[0021] like Figure 1 As shown, the receiving optical path 3 is also equipped with an SC adapter 4 for receiving optical signals. The SC adapter 4 and the reflective filter 6 are arranged on the same horizontal line. The optical signal received by the SC adapter 4 is processed by the reflective filter 6, the tilt filter 7, the RX converging lens 5, and the 0-degree filter 8 in sequence before entering the optical receiving module 2.
[0022] It should be noted that, in addition to total reflection, the above-mentioned reflective filter 6 also has total transmission function. In practical applications, the reflective filter 6 can be used with the optical emission module to enable the optical signal emitted by the optical emission module to reach the SC adapter 4 and be output after reflection and transmission.
[0023] like Figure 1 As shown, in order to improve the stability of the receiving optical path 3, a housing 1 is further provided, and the optical receiving module 2, 0-degree filter 8, RX converging lens 5, tilt filter 7, reflection filter 6 and SC adapter 4 are all fixed into a whole by the housing 1.
[0024] The principle of receiving dual-wavelength optical signals in this invention is as follows: After receiving an external optical signal, the optical signal passes through the SC adapter 4 and is incident on the reflective filter 6. The optical signal undergoes total internal reflection on the reflective filter 6 and is then incident on the tilted filter 7 at an 8-degree angle. The tilted filter 7 allows complete transmission of optical signals with wavelengths in the range of 1350–1360 nm, and allows total internal reflection of optical signals with wavelengths in the ranges of 1300–1344 nm and 1364–1400 nm, which are then incident vertically upwards onto the 0-degree filter 8, achieving an isolation of 35 dB. After receiving the optical signal, the 0-degree filter 8 filters out the remaining wavelength ranges, allowing only the optical signals in the wavelength ranges of 1342±2 nm and 1366±2 nm to be transmitted to the optical receiving module 2, thus enabling flexible reception of optical signals in these two wavelength ranges.
[0025] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent features unless otherwise specified. All features or steps in all methods or processes disclosed may be combined in any way, except for mutually exclusive features and / or steps.
Claims
1. A method for receiving dual-wavelength optical signals in a 50G ONU optical device, characterized in that: The optical receiving module (2) includes a 0-degree filter (8), a tilt filter (7), and a reflection filter (6) sequentially arranged on the receiving optical path (3). The received optical signal is processed by the reflection filter (6), the tilt filter (7), and the 0-degree filter (8) in sequence to obtain optical signals with wavelength ranges of 1342±2nm and 1366±2nm, which then enter the optical receiving module (2). Each filter should meet the following technical requirements: S1. The reflective filter (6) is fixed at an angle of 37 degrees to the vertical axis on the lower left side of the optical receiving module (2) to satisfy the total reflection of the received optical signal and to satisfy the total reflection of the optical signal to be incident downward at an angle of 8 degrees onto the tilted filter (7). S2. The tilted filter (7) has a passband with a wavelength range of 1350~1360nm and a stopband with a wavelength range of 1300~1344nm and 1364~1400nm; the tilted filter (7) is fixed below the optical receiving module (2) at an angle of 8 degrees to the horizontal plane, so as to ensure that all optical signals with a wavelength range of 1350~1360nm are transmitted, and to ensure that all optical signals with a wavelength range of 1300~1344nm and 1364~1400nm are reflected vertically upward; The S3.0 degree filter (8) has a filter passband with a wavelength range of 1340~1368nm and a filter stopband with a wavelength range of 1300~1335nm and 1373~1400nm; the 0 degree filter (8) is horizontally fixed directly below the optical receiving module (2) to satisfy the requirement that the light signal totally reflected by the tilted filter (7) is incident on the 0 degree filter (8) at a 0 degree incident angle, and to satisfy the requirement that the light signals with wavelength ranges of 1342±2nm and 1366±2nm are transmitted to the optical receiving module (2).
2. The dual-wavelength optical signal receiving method for a 50G ONU optical device according to claim 1, characterized in that: An RX converging lens (5) is also fixed on the receiving optical path (3). The RX converging lens (5) is located between the 0-degree filter (8) and the tilted filter (7), and is close to the 0-degree filter.
3. The dual-wavelength optical signal receiving method for a 50G ONU optical device according to claim 2, characterized in that: The receiving optical path (3) is also provided with an SC adapter (4) for receiving optical signals. The optical signals received by the SC adapter (4) are processed in sequence by a reflection filter (6), a tilt filter (7), an RX converging lens (5), and a 0-degree filter (8) before entering the optical receiving module (2).
4. The dual-wavelength optical signal receiving method for a 50G ONU optical device according to claim 3, characterized in that: The reflective filter (6) and the SC adapter (4) are arranged on the same horizontal line, and the 0-degree filter (8) and the tilted filter (7) are located above and below the reflective filter (6), respectively.
5. The dual-wavelength optical signal receiving method for a 50G ONU optical device according to claim 3, characterized in that: The optical receiving module (2), 0-degree filter (8), RX converging lens (5), tilt filter (7), reflection filter (6) and SC adapter (4) are all fixed together as a whole by the housing (1).