A 50G PON optical device with improved wavelength division multiplexing isolation

Abstract

This invention discloses a 50G PON optical device with improved wavelength division multiplexing (WDM) isolation, relating to the field of optical device technology. It includes a PLC chip with a main port and an RX wavelength division multiplexing unit. The RX WDM unit comprises an input planar waveguide, an arrayed waveguide, an output planar waveguide, three fan-out waveguides, and three output ports. The input planar waveguide is used to generate a diffracted beam from the composite optical signal and uniformly project it into the arrayed waveguide. The arrayed waveguide is used to separate the beam into optical signals of different wavelengths. The output planar waveguide is used to guide the optical signals to the respective fan-out waveguides, and each fan-out waveguide transmits the corresponding wavelength optical signal to its respective output port with an isolation greater than 30 dB. This optical device can solve the technical problem of low isolation between optical signals after wavelength division multiplexing in existing 50G PON optical devices while reducing optical loss.

Description

Technical Field

[0001] This invention relates to the field of optical device technology, and specifically to a 50G PON optical device with improved wavelength division isolation. Background Technology

[0002] Currently, conventional 50G PON optical devices mainly use block elements to achieve the multiplexing and demultiplexing of optical signals of different wavelengths, such as... Figure 6 As shown, the Block element 27 has a main port 2 and a three-way splitter / combiner optical port 28. In actual use, after the three optical signals enter the Block element 27 through the splitter / combiner optical port 28, a composite optical signal can be output from the main port 2. Conversely, the Block element 27 can be used to separate the externally input composite optical signal into three optical signals of different wavelengths at the main port 2 and output them through the splitter / combiner optical port 28, thereby ultimately realizing the effective transmission of optical signals.

[0003] However, with the increasing demand for higher bandwidth from users and the development of emerging applications such as 4K / 8K video, virtual reality (VR), augmented reality (AR), and the Internet of Things (IoT), higher requirements are being placed on optical devices. For example, in access network applications, the new 50G PON optical device consists of three transmit wavelengths (TX 1577±5nm, TX 1490±10nm, and TX 1342±2nm) and three receive wavelengths (RX 1310±20nm, RX 1286±2nm, and RX 1270±10nm), all sharing a single main port for transmission and reception. Based on actual communication requirements, the isolation between the RX ports within the optical device must be greater than 30dB during operation to prevent interference between the optical signals and maintain communication stability. However, since the Block element achieves the multiplexing / demultiplexing function through coating, when it is applied to multiplexing / demultiplexing of the above 6 wavelength optical signals, its isolation can only reach 20dB, which makes it unable to meet the market demand for increasingly higher transmission rates.

[0004] Therefore, there is an urgent need to develop a 50G PON optical device with higher isolation. Summary of the Invention

[0005] To overcome the aforementioned technical problems in the prior art, the present invention provides a 50G PON optical device with improved wavelength division isolation. This optical device can solve the technical problem of low isolation between optical signals after wavelength division processing of composite optical signals in existing 50G PON optical devices, while reducing optical loss.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A 50G PON optical device with improved wavelength division isolation includes a PLC chip, wherein the PLC chip is provided with a main port for receiving external composite optical signals and an RX wavelength division unit for separating the composite optical signals into three optical signals of different wavelengths and outputting them.

[0008] The RX wave division unit includes an input planar waveguide, an arrayed waveguide, an output planar waveguide, an RX1270 fan-out waveguide, an RX1286 fan-out waveguide, an RX1310 fan-out waveguide, a 1270 output port, a 1286 output port, and a 1310 output port. The input planar waveguide, arrayed waveguide, and output planar waveguide are sequentially connected to the main port. The RX1270, RX1286, and RX1310 fan-out waveguides are all connected to the output planar waveguide. The 1270, 1286, and 1310 output ports are respectively connected to the RX1270, RX1286, and RX1310 fan-out waveguides.

[0009] The input planar waveguide is used to generate a diffracted beam from the received composite optical signal and project it uniformly into the array waveguide. The array waveguide, based on the principles of diffraction and phase delay, is used to separate the beam into different wavelengths and project them into different output channels. The output planar waveguide is used to guide the optical signals of different wavelengths in each output channel to the RX1270 fan-out waveguide, RX1286 fan-out waveguide, and RX1310 fan-out waveguide, respectively. The RX1270 fan-out waveguide, RX1286 fan-out waveguide, and RX1310 fan-out waveguide are used to transmit the optical signals of the corresponding wavelengths to the 1270 output port, 1286 output port, and 1310 output port, respectively, with an isolation of greater than 30dB.

[0010] The PLC chip has a wavelength dispersion of 0.2 nm / µm. The array waveguide consists of 152 waveguides of equal length. There is a 10µm gap between the RX1270 fan-out waveguide and the RX1286 fan-out waveguide, and a 20µm gap between the RX1286 fan-out waveguide and the RX1310 fan-out waveguide. The RX1286 fan-out waveguide includes 8 waveguides, the RX1270 fan-out waveguide includes 40 waveguides, and the RX1310 fan-out waveguide includes 80 waveguides. The spacing between adjacent waveguides in the RX1286, RX1270, and RX1310 fan-out waveguides is 3µm.

[0011] The 1270 output port, 1286 output port and 1310 output port are respectively connected to the 1270 APD chip, 1286 APD chip and 1310 APD chip through RX coupling lenses.

[0012] The PLC chip is also equipped with a TX multiplexing unit, which is used to combine three optical signals of different wavelengths into one composite optical signal and output it to the outside through the main port.

[0013] The TX multiplexing unit is an AWG multiplexer that includes 1342 input ports, 1490 input ports, and 1577 input ports.

[0014] The 1342 input port is connected in sequence to a converging lens, an isolator, a collimating lens, and a 1342 EML chip. A light signal with a wavelength of 1342nm enters the 1342 input port through the 1342 EML chip, the collimating lens, the isolator, and the converging lens in sequence.

[0015] The 1490 input port is connected in sequence to a converging lens, an isolator, a collimating lens, and a 1490 DFB chip. The optical signal with a wavelength of 1490nm emitted by the 1490DFB chip enters the 1490 input port in sequence through the collimating lens, the isolator, and the converging lens.

[0016] The 1577 input port is connected in sequence to a converging lens, an isolator, a collimating lens, and a 1577 EML chip. The optical signal with a wavelength of 1577nm emitted by the 1577EML chip enters the 1577 input port in sequence through the collimating lens, the isolator, and the converging lens.

[0017] The 50G PON optical device also includes a BOX housing for encapsulating the PLC chip.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. This invention introduces a PLC chip and a corresponding RX demultiplexing unit designed on the PLC chip, including an input planar waveguide, an arrayed waveguide, an output planar waveguide, an RX1270 fan-out waveguide, an RX1286 fan-out waveguide, an RX1310 fan-out waveguide, a 1270 output port, a 1286 output port, and a 1310 output port. This achieves a separation degree greater than 30dB between optical signals after wavelength division processing of composite optical signals within the optical device, while reducing optical loss. Compared to conventional 50G PON optical devices, this not only meets communication requirements but also avoids interference between optical signals, thus effectively improving the reliability and stability of the communication system.

[0020] 2. The receiver of this invention uses an APD chip, which can effectively improve the receiver sensitivity. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the planar structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the planar structure of a PLC chip;

[0023] Figure 3 This is a schematic diagram of the planar structure of the RX demultiplexer unit;

[0024] Figure 4 A schematic diagram of the structure from the output planar waveguide to the fan-out waveguide in the RX demultiplexing unit;

[0025] Figure 5 This is a spectrum diagram of an optical signal transmitted by a PLC chip through an RX wavelength division unit.

[0026] Figure 6 This is a schematic diagram of the planar structure of an existing Block element.

[0027] The following are labeled in the diagram: 1. PLC chip, 2. Main port, 3. RX demultiplexer unit, 4. Input planar waveguide, 5. Array waveguide, 6. Output planar waveguide, 7. RX1270 fan-out waveguide, 8. RX1286 fan-out waveguide, 9. RX1310 fan-out waveguide, 10. 1270 output port, 11. 1286 output port, 12. 1310 output port, 13. RX coupling lens, 14. 1270 APD chip, 15. 1286 APD chip, 16. 1310 APD chip, 17. TX multiplexing unit, 18. 1342 input port, 19. 1490 input port, 20. 1577 input port, 21. Converging lens, 22. Isolator, 23. Collimating lens, 24. 1342 EML chip, 25. 1490 DFB chip, 26. 1577 EML chip, 27. Block component, 28. Optical port for splitting and combining. Detailed Implementation

[0028] This invention provides a 50G PON optical device with improved wavelength division multiplexing isolation. The optical device incorporates a PLC chip 1 based on silicon-based PLC planar waveguide technology. Through the PLC chip 1, the optical device can perform wavelength division multiplexing processing of optical signals with three transmit wavelengths (TX 1577±5nm, TX 1490±10nm, and TX 1342±2nm) and high-isolation wavelength division multiplexing processing of optical signals with three receive wavelengths (RX 1310±20nm, RX 1286±2nm, and RX 1270±10nm).

[0029] like Figure 1 , 2As shown, the optical device includes a PLC chip 1. The PLC chip 1 is equipped with a main port 2, a TX multiplexing unit 17, and an RX demultiplexing unit 3. The TX multiplexing unit 17 is used to combine three optical signals of different wavelengths into one composite optical signal. The main port 2 is used to output the composite optical signal after multiplexing by the TX multiplexing unit 17 to the outside and to receive composite optical signals input from the outside. The RX demultiplexing unit 3 is used to separate the composite optical signal into three optical signals of different wavelengths and output them.

[0030] like Figure 1-3 As shown, specifically, the RX demultiplexer unit 3 includes an input planar waveguide 4, an array waveguide 5, an output planar waveguide 6, an RX1270 fan-out waveguide 7, an RX1286 fan-out waveguide 8, an RX1310 fan-out waveguide 9, a 1270 output port 10, a 1286 output port 11, and a 1310 output port 12. The input planar waveguide 4, the array waveguide 5, and the output planar waveguide 6 are sequentially connected to the main port 2. The RX1270 fan-out waveguide 7, the RX1286 fan-out waveguide 8, and the RX1310 fan-out waveguide 9 are all connected to the output planar waveguide 6. The 1270 output port 10, the 1286 output port 11, and the 1310 output port 12 are respectively connected to the RX1270 fan-out waveguide 7, the RX1286 fan-out waveguide 8, and the RX1310 fan-out waveguide 9. In addition, the 1270 output port 10, 1286 output port 11, and 1310 output port 12 are respectively connected to the 1270 APD chip 14, 1286 APD chip 15, and 1310 APD chip 16 via RX coupling lenses 13. The RX coupling lenses 13 are used to couple optical signals to each chip.

[0031] The input planar waveguide 4 is used to generate a diffracted beam from the received composite optical signal and project it uniformly into the array waveguide 5, ensuring minimal signal loss and uniform light field distribution during transmission. The array waveguide 5, based on the principles of diffraction and phase delay, separates the beam into different wavelengths and projects them into different output channels. The output planar waveguide 6 guides the optical signals of different wavelengths from each output channel to the RX1270 fan-out waveguide 7, RX1286 fan-out waveguide 8, and RX1310 fan-out waveguide 9, respectively. The RX1270 fan-out waveguide 7, RX1286 fan-out waveguide 8, and RX1310 fan-out waveguide 9 transmit the corresponding wavelength optical signals with an isolation greater than 30dB to the 1270 output port 10, 1286 output port 11, and 1310 output port 12, respectively. The 1270 APD chip 14 receives optical signals with a wavelength of 1270nm through the RX coupling lens 13. APD chip 15 is used to receive optical signals with a wavelength of 1286nm through RX coupling lens 13, and APD chip 16 is used to receive optical signals with a wavelength of 1310nm through RX coupling lens 13.

[0032] like Figure 4 As shown, preferably, the wavelength dispersion of PLC chip 1 is 0.2 nm / µm, and the array waveguide 5 consists of 152 waveguides of equal length, which can separate the optical signal into different wavelengths and project them into different output channels. The RX1286 fan-out waveguide 8 includes 8 waveguides, the RX1270 fan-out waveguide 7 includes 40 waveguides, and the RX1310 fan-out waveguide 9 includes 80 waveguides. The spacing between adjacent waveguides in the RX1286 fan-out waveguide 8, the RX1270 fan-out waveguide 7, and the RX1310 fan-out waveguide 9 is 3µm. Thus, the RX1286 fan-out waveguide 8 can capture a total spectrum of 8 x 3 x 0.2 = 4.8 nm, which is sufficient to completely extract optical signals in the 1286 ± 2 nm range onto the 1286 output port 11. Similarly, the RX1270 fan-out waveguide 7 can capture a total spectral width of 40 x 3 x 0.2 = 24 nm, which is sufficient to completely extract optical signals in the range of 1270 ± 10 nm onto the 1270 output port 10. The RX1310 fan-out waveguide 9 can capture a total spectral width of 80 x 3 x 0.2 = 48 nm, which is sufficient to completely extract optical signals in the range of 1310 ± 20 nm onto the 1310 output port 12.

[0033] In addition, there is a 10µm gap between the RX1270 fan-out waveguide 7 and the RX1286 fan-out waveguide 8. This 10µm gap does not have a corresponding fan-out waveguide for receiving the demultiplexed optical signal, which is equivalent to creating a 10x0.2=2nm wide stopband region, thereby achieving good isolation within a 2nm spectral interval.

[0034] Similarly, there is a 20µm gap between the RX1286 fan-out waveguide 8 and the RX1310 fan-out waveguide 9. This 20µm gap does not have a corresponding fan-out waveguide for receiving the demultiplexed optical signal, which is equivalent to creating a 20 x 0.2 = 4nm wide stopband region, thereby achieving good isolation within a 4nm spectral interval.

[0035] like Figure 1 As shown, in this embodiment, the TX multiplexing unit 17 is an AWG multiplexer including a 1342 input port 18, a 1490 input port 19, and a 1577 input port 20. Wherein,

[0036] The 1342 input port 18 is connected in sequence to a converging lens 21, an isolator 22, a collimating lens 23, and a 1342 EML chip 24. The optical signal with a wavelength of 1342nm emitted by the 1342 EML chip 24 enters the 1342 input port 18 through the collimating lens 23, the isolator 22, and the converging lens 21. Both the collimating lens 23 and the converging lens 21 couple the optical signal, while the isolator 22 isolates the reflected light from entering the EML or DFB chip, thus preventing it from affecting the normal operation of the chip.

[0037] The 1490 input port 19 is connected in sequence to a converging lens 21, an isolator 22, a collimating lens 23, and a 1490 DFB chip 25. The optical signal with a wavelength of 1490nm emitted by the 1490 DFB chip 25 enters the 1490 input port 19 in sequence through the collimating lens 23, the isolator 22, and the converging lens 21.

[0038] The 1577 input port 20 is connected in sequence to a converging lens 21, an isolator 22, a collimating lens 23 and a 1577 EML chip 26. The optical signal with a wavelength of 1577nm emitted by the 1577 EML chip 26 enters the 1577 input port 20 in sequence through the collimating lens 23, the isolator 22 and the converging lens 21.

[0039] After receiving three optical signals through input ports 1342 (18), 1490 (19), and 1577 (20), PLC chip 1 combines them into a single composite optical signal and outputs it through port 2.

[0040] like Figure 1 As shown, in this embodiment, the 50G PON optical device also includes a BOX housing. The PLC chip 1 and other components are all encapsulated in the BOX housing to form a complete 50G PON optical device.

[0041] like Figure 5As shown, this application provides a simulated transmission spectrum of the optical device. Observing the spectrum of the RX 1286±2nm window (i.e., the black solid line), the loss is almost 0 in this window range. The loss is -45dB in the RX 1270±10nm window (i.e., there is 45dB isolation between the two ports), and the loss is -35dB in the RX 1310±20nm window (i.e., there is 35dB isolation between the two ports). Since the isolation between ports is independent of the spectral width of each port, the isolation between all RX ports is greater than 30dB, thereby effectively improving the isolation between the optical signals after wavelength division processing.

[0042] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All features or steps in the disclosed methods or processes may be combined in any way, except for mutually exclusive features and / or steps.

Claims

1. A 50G PON optical device for improving wavelength division multiplexing isolation, comprising a PLC chip (1), characterized in that: The PLC chip (1) is provided with a total port (2) for receiving an external composite optical signal and an RX splitting unit (3) for splitting the composite optical signal into three different wavelength optical signals and outputting; The RX splitting unit (3) comprises an input slab waveguide (4), an array waveguide (5), an output slab waveguide (6), an RX1270 fan-out waveguide (7), an RX1286 fan-out waveguide (8), an RX1310 fan-out waveguide (9), a 1270 output port (10), a 1286 output port (11) and a 1310 output port (12), the input slab waveguide (4), the array waveguide (5) and the output slab waveguide (6) are sequentially connected to the total port (2), the RX1270 fan-out waveguide (7), the RX1286 fan-out waveguide (8) and the RX1310 fan-out waveguide (9) are all connected to the output slab waveguide (6), and the 1270 output port (10), the 1286 output port (11) and the 1310 output port (12) are respectively connected to the RX1270 fan-out waveguide (7), the RX1286 fan-out waveguide (8) and the RX1310 fan-out waveguide (9); wherein, The input slab waveguide (4) is used for making the received composite optical signal produce diffracted beams and uniformly project into the array waveguide (5); the array waveguide (5) is used for separating the beams into different wavelengths and projecting into different output channels based on the principle of diffraction and phase delay; the output slab waveguide (6) is used for guiding the optical signals of different wavelengths in each output channel into the RX1270 fan-out waveguide (7), the RX1286 fan-out waveguide (8) and the RX1310 fan-out waveguide (9) respectively, and the RX1270 fan-out waveguide (7), the RX1286 fan-out waveguide (8) and the RX1310 fan-out waveguide (9) are used for transmitting the optical signals of corresponding wavelengths to the 1270 output port (10), the 1286 output port (11) and the 1310 output port (12) respectively with an isolation of more than 30dB; The wavelength dispersion of the PLC chip (1) is 0.2 nm / um, the array waveguide (5) is composed of 152 waveguides with equal difference length, there is a gap of 10 um between the RX1270 fan-out waveguide (7) and the RX1286 fan-out waveguide (8), which corresponds to generating a 10x0.2=2 nm wide stopband region, thereby realizing good isolation within a spectral interval of 2 nm; there is a gap of 20 um between the RX1286 fan-out waveguide (8) and the RX1310 fan-out waveguide (9), which corresponds to generating a 20x0.2=4 nm wide stopband region, thereby realizing good isolation within a spectral interval of 4 nm; the RX1286 fan-out waveguide (8) includes 8 waveguides, the RX1270 fan-out waveguide (7) includes 40 waveguides, and the RX1310 fan-out waveguide (9) includes 80 waveguides; the spacing between adjacent waveguides in the RX1286 fan-out waveguide (8), the RX1270 fan-out waveguide (7) and the RX1310 fan-out waveguide (9) is 3 um; the RX1286 fan-out waveguide (8) can capture a total of 8x3x0.2=4.8 nm wide spectrum, and can completely extract the optical signal in the range of 1286±2 nm to the 1286 output port 11; similarly, the RX1270 fan-out waveguide (7) can capture a total of 40x3x0.2=24 nm wide spectrum, and can completely extract the optical signal in the range of 1270±10 nm to the 1270 output port (10); the RX1310 fan-out waveguide (9) can capture a total of 80x3x0.2=48 nm wide spectrum, and can completely extract the optical signal in the range of 1310±20 nm to the 1310 output port (12). 2.The 50G PON optical device of claim 1, wherein: the first and second 50G PON optical signals are transmitted in a same direction; and the first and second 50G PON optical signals are transmitted in a same polarization direction. The 1270 output port (10), the 1286 output port (11) and the 1310 output port (12) are respectively connected with a 1270 APD chip (14), a 1286 APD chip (15) and a 1310 APD chip (16) through RX coupling lenses (13). 3.The 50G PON optical device of claim 1 or 2, wherein: the first and second 50G PON optical signals are transmitted in the same direction; and the first and second 50G PON optical signals are transmitted in opposite directions. The TX combining unit (17) is further arranged on the PLC chip (1), and the TX combining unit (17) is used for combining three optical signals with different wavelengths into a composite optical signal and outputting the composite optical signal to the outside through the total port (2).

4. A 50G PON optical device for improving wavelength division isolation according to claim 3, characterized in that: The TX combining unit (17) is an AWG combiner including a 1342 input port (18), a 1490 input port (19) and a 1577 input port (20).

5. The 50G PON optical device for improving the wavelength separation isolation degree according to claim 4, characterized in that: The 1342 input port (18) is sequentially connected with a converging lens (21), an isolator (22), a collimating lens (23) and a 1342 EML chip (24), and the optical signal with a wavelength of 1342 nm emitted by the 1342 EML chip (24) enters the 1342 input port (18) through the collimating lens (23), the isolator (22) and the converging lens (21) in sequence. 6.The 50G PON optical device of claim 4, wherein: The 1490 input port (19) is sequentially connected with a converging lens (21), an isolator (22), a collimating lens (23) and a 1490 DFB chip (25), the light signal with a wavelength of 1490 nm emitted by the 1490 DFB chip (25) enters the 1490 input port (19) through the collimating lens (23), the isolator (22) and the converging lens (21) in sequence. 7.The 50G PON optical device of claim 4, wherein: the first and second 50G PON optical signals are transmitted in a same direction; and the first and second 50G PON optical signals are transmitted in a same direction. The 1577 input port (20) is sequentially connected with a converging lens (21), an isolator (22), a collimating lens (23) and a 1577 EML chip (26), the light signal with a wavelength of 1577 nm emitted by the 1577 EML chip (26) enters the 1577 input port (20) through the collimating lens (23), the isolator (22) and the converging lens (21) in sequence. 8.The 50G PON optical device of claim 1, wherein: the first and second 50G PON optical signals are transmitted in a same direction; and the first and second 50G PON optical signals are transmitted in a same direction. The 50G PON optical device further comprises a BOX shell for packaging the PLC chip (1).

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