Optical splitter, combiner and optical communication device

Abstract

The application discloses a wave divider, a wave combiner and an optical communication device, and belongs to the technical field of optical communication. The wave divider comprises a first filter device and a second filter device. The first filter device is used for dividing an input light beam into a first light beam and a second light beam, the first light beam is light of a first wave band, the second light beam comprises light of a second wave band and light of a third wave band, and the first wave band is located between the second wave band and the third wave band. The second filter device is used for dividing the second light beam into a first sub-light beam and a second sub-light beam, the first sub-light beam is light of the second wave band, and the second sub-light beam is light of the third wave band. The width of a first transition wave band range of the first filter device is less than the width of a second transition wave band range of the second filter device, and the first wave band at least partially coincides with the second transition wave band range. The wave combiner has the same device composition as the wave divider, and the transmission process of light is the reverse process of the wave divider. The wave divider and the wave combiner can improve the utilization rate of light.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a demultiplexer, a multiplexer, and an optical communication device. Background Technology

[0002] With the development of optical communication technology, the transmission capacity of optical communication systems is constantly increasing, and the bandwidth of the optical bands used in optical communication systems is also growing. In optical communication systems, it is often necessary to use a wavelength division multiplexer (WDM) to perform wavelength division processing or a wavelength multiplexer (WMP) to perform wavelength multiplexing processing.

[0003] In related technologies, both demultiplexers and multiplexers can be implemented using filter devices. Based on the optical characteristics of filter devices, if light within the transition wavelength range of the filter device is input into it, that portion of the light will be lost and unable to pass through the filter device. The following sections will explain demultiplexers and multiplexers separately.

[0004] When this filter device is used as a wavelength divider, it splits the input beam into a first beam and a second beam. The input beam includes light within the transition wavelength range of the filter device, while the first and second beams correspond to different wavelength bands. The wavelength bands corresponding to the first and second beams are located on opposite sides of the transition wavelength range. In other words, the output beam of the filter device does not include light within its own transition wavelength range.

[0005] When the filter device acts as a combiner, it combines the received first and second beams into an output beam. The first beam includes light in one wavelength band and light within the transition wavelength range of the filter device, while the second beam includes light in another wavelength band. The wavelength bands corresponding to the first and second beams are located on opposite sides of the transition wavelength range. The resulting output beam includes only the light in the first and second wavelength bands, excluding light within the transition wavelength range of the filter device.

[0006] It is evident that during the wave splitting and combining process of this filtering device, light within the transition wavelength range of the filtering device is lost due to the optical characteristics of the filtering device, resulting in low light utilization. Summary of the Invention

[0007] This application provides a wavelength division multiplexer, a wavelength multiplexer, and an optical communication device that can improve the utilization rate of light.

[0008] On one hand, this application provides a wavelength division multiplexing (WDM). The WDM includes a first filter and a second filter. The first filter splits an input light beam into a first beam and a second beam. The first beam is light in a first wavelength band, and the second beam includes light in a second wavelength band and light in a third wavelength band, with the first wavelength band located between the second and third wavelength bands. The second filter splits the second beam into a first sub-beam and a second sub-beam. The first sub-beam is light in the second wavelength band, and the second sub-beam is light in the third wavelength band. The width of a first transition wavelength range of the first filter is smaller than the width of a second transition wavelength range of the second filter, and the first wavelength band and the second transition wavelength range at least partially overlap.

[0009] The input beam first passes through a first filter, which separates the light of the first wavelength band from the input beam as the first beam. Then, a second filter further splits the light of other wavelength bands in the input beam, i.e., it performs wave-splitting processing on the second beam. Since the width of the first transition wavelength range of the first filter is smaller than the width of the second transition wavelength range of the second filter, and the first wavelength band and the second transition wavelength range at least partially overlap, at least a portion of the second transition wavelength range can still be used compared to the light corresponding to the entire second transition wavelength range that is lost when the second filter directly processes the input beam. This reduces the width of the wavelength range corresponding to the lost light and improves the utilization rate of the optical band corresponding to the input beam.

[0010] In this application, the input beam is light in a single wavelength band, typically a sub-interval of 1260nm to 1625nm. The 1260nm to 1625nm wavelength band is a low-loss wavelength region in optical communication systems.

[0011] In some examples, the first filtering device is a bandpass filter device, which is used to transmit light of the first wavelength band to obtain the first beam, and to reflect light of the second wavelength band and the third wavelength band to obtain the second beam.

[0012] In some examples, the second filtering device is an edge-type filtering device, which is used to reflect light of the second band to obtain the first sub-beam, and to transmit light of the third band to obtain the second sub-beam.

[0013] In some examples, the wavelength division multiplexer further includes a wavelength multiplexing component for combining the first beam and the first sub-beam into a first mixed beam. By combining the first beam and the first sub-beam into the first mixed beam and outputting it, the wavelength band corresponding to the input beam can be divided into two bands.

[0014] In some examples, the first filtering component is multiplexed as part of the multiplexing assembly, which reduces the number of optical components included in the demultiplexer, thus reducing size and cost. Furthermore, the optical path structure is simple and easy to modulate and assemble.

[0015] For example, the beam combiner includes a reflecting device. The reflecting device is used to reflect the first sub-beam to the first filtering device. The first filtering device is also used to reflect the first sub-beam from the reflecting device to combine the first sub-beam with the first beam into the first mixed beam.

[0016] For example, the beam combiner includes a reflector. The reflector is used to reflect the first beam to the first filter; the first filter is also used to transmit the first beam from the reflector and reflect the first sub-beam from the second filter, so as to combine the first sub-beam with the first beam into the first mixed beam.

[0017] In some examples, the absolute value of the difference between any two of the first, second, and third included angles is no greater than 3°. Optionally, the absolute value of the difference between any two of the first, second, and third included angles is no greater than 0.5°. Wherein, the first included angle is the angle between the first propagation path and the second propagation path, the first propagation path being the path of the input beam incident on the first filter device, and the second propagation path being the path of the second beam from the first filter device to the second filter device; the second included angle is the angle between the second propagation path and the third propagation path, the third propagation path being the path of the first sub-beam from the second filter device to the first filter device; the third included angle is the angle between the third propagation path and the fourth propagation path, the fourth propagation path being the path of the second sub-beam after reflection by the first filter device.

[0018] By reflecting and folding the second sub-beam using a reflective device, the optical path lengths of the first beam and the first sub-beam are made very close or even the same. This avoids coupling loss and phase difference caused by optical path difference, which helps to further reduce the loss of the demultiplexer.

[0019] In some other examples, the multiplexing assembly uses additional filtering components to achieve multiplexing. Using additional filtering components allows for greater flexibility in the placement and structure of the devices, which helps reduce debugging difficulty.

[0020] For example, the beam combiner includes a reflector and a third filter. The reflector reflects the first sub-beam from the second filter to the third filter. The third filter transmits the first beam from the first filter and reflects the first sub-beam from the reflector to combine the first beam and the first sub-beam into the first mixed beam.

[0021] For example, the beam combiner includes a reflector and a fourth filter. The reflector reflects the first beam from the first filter to the fourth filter. The fourth filter transmits the first beam from the reflector and reflects the first sub-beam from the second filter to combine the first beam and the first sub-beam into the first mixed beam.

[0022] In some examples, the propagation paths of the first beam from the first filter to the reflector, the propagation paths of the first beam from the reflector to the fourth filter, the propagation paths of the first sub-beam from the first filter to the second filter, and the propagation paths of the first sub-beam from the second filter to the fourth filter are arranged in a parallelogram.

[0023] When these propagation paths are arranged in a parallelogram, the optical path lengths of the first beam and the first sub-beam are basically the same, which can avoid coupling loss and phase difference caused by optical path difference, and help to further reduce the loss of the splitter.

[0024] Optionally, to improve the isolation of the device, the splitter further includes at least one intermediate filter, which is used for at least one of the following: guiding the second beam from the first filter to the second filter, guiding the first sub-beam from the second filter to the fourth filter, and outputting the second sub-beam from the second filter.

[0025] The aforementioned wavelength splitters are all used to separate two wavelength bands. When separation of more wavelength bands is required, the wavelength splitter further includes a fifth filter and a sixth filter. The fifth filter is used to split the first mixed beam into a third beam and a fourth beam. The third beam is light from a first sub-band, and the fourth beam includes light from a second sub-band and a third sub-band. The first sub-band is located between the second and third sub-bands. The sixth filter is used to split the fourth beam into a third sub-beam and a fourth sub-beam. The third sub-beam is light from the second sub-band, and the fourth sub-beam is light from the third sub-band. The width of the third transition wavelength range of the fifth filter is smaller than the width of the fourth transition wavelength range of the sixth filter, and the first sub-band and the fourth transition wavelength range at least partially overlap.

[0026] The fifth and sixth filtering devices can further divide the band corresponding to the first mixed beam into multiple bands, thereby achieving the separation of more bands.

[0027] In other examples, the wave combiner is used to combine the first beam and the first sub-beam into a first mixed beam. By combining the first beam and the second sub-beam into a first mixed beam and outputting it, the waveband corresponding to the input beam can also be divided into two wavebands to adapt to different waveband division requirements.

[0028] Exemplarily, the beam combiner includes a first reflector, a second reflector, and an eighth filter. The first reflector reflects a first beam from the first filter to the eighth filter. The second reflector reflects a second sub-beam from the second filter to the eighth filter. The eighth filter transmits the first beam from the first reflector and reflects the second sub-beam from the second reflector to combine the first beam and the second sub-beam into a first mixed beam.

[0029] On the other hand, this application provides a beam combiner. The beam combiner includes a first filter and a second filter. The second filter is used to combine a first sub-beam and a second sub-beam into a second beam, wherein the first sub-beam is light in a second wavelength band and the second sub-beam is light in a third wavelength band. The first filter is used to combine the first beam and the second beam into an output beam, wherein the first beam is light in a first wavelength band located between the second wavelength band and the third wavelength band. Specifically, the width of a first transition wavelength range of the first filter is smaller than the width of a second transition wavelength range of the second filter, and the first wavelength band at least partially overlaps with the second transition wavelength range.

[0030] In some examples, the first filtering device is a bandpass filter device, which is used to transmit the first beam and reflect the second beam to combine the first beam and the second beam into the output beam.

[0031] In some examples, the second filter is an edge filter that transmits the second sub-beam and reflects the first sub-beam to combine the first sub-beam and the second sub-beam into the second beam.

[0032] Optionally, the beam combiner further includes a beam splitter assembly for receiving a first mixed beam and splitting the first mixed beam into a first beam and a first sub-beam.

[0033] In some examples, the wavelength division component includes a reflector. The first filter element is further configured to split the first mixed beam into the first beam and the first sub-beam, and to reflect the first sub-beam to the reflector. The reflector is configured to reflect the first sub-beam to the second filter element.

[0034] In other examples, the wavelength division component includes a reflector. The first filter element is further configured to split the first mixed beam into the first beam and the first sub-beam, and to transmit the first beam to the reflector. The reflector is configured to reflect the first beam from the first filter element back to the first filter element; the first filter element is also configured to transmit the first beam from the reflector.

[0035] For example, the absolute value of the difference between any two of the first, second, and third included angles is not greater than 3°; optionally, the absolute value of the difference between any two of the first, second, and third included angles is not greater than 0.5°. Wherein, the first included angle is the angle between the first propagation path and the second propagation path, the first propagation path being the path of the output beam exiting from the first filter device, and the second propagation path being the path of the second beam from the first filter device to the first filter device; the second included angle is the angle between the second propagation path and the third propagation path, the third propagation path being the path of the first sub-beam from the first filter device to the first filter device; the third included angle is the angle between the third propagation path and the fourth propagation path, the fourth propagation path being the path of the first mixed beam incident on the first filter device.

[0036] In some other examples, the wavelength division component includes a reflector and a third filter. The third filter is used to split the first mixed beam into the first beam and the first sub-beam, guide the first beam to the first filter, and guide the first sub-beam to the reflector. The reflector is used to reflect the first sub-beam from the third filter to the second filter.

[0037] In some other examples, the wavelength division component includes a reflector and a fourth filter. The fourth filter is used to split the first mixed beam into a first beam and a first sub-beam, guide the first beam to the reflector, and guide the first sub-beam to the second filter. The reflector is used to reflect the first beam from the fourth filter back to the first filter.

[0038] For example, the propagation paths of the first beam from the fourth filter device to the reflector, the propagation paths of the first beam from the reflector device to the first filter device, the propagation paths of the first sub-beam from the fourth filter device to the second filter device, and the propagation paths of the first sub-beam from the second filter device to the first filter device are arranged in a parallelogram.

[0039] Optionally, the combiner further includes at least one intermediate filter element, the at least one intermediate filter element being configured to: guide the first sub-beam from the fourth filter element to the second filter element, guide the first sub-beam from the second filter element to the first filter element, and guide the second sub-beam to the second filter element.

[0040] Optionally, the combiner further includes a fifth filter and a sixth filter. The sixth filter is used to combine the third sub-beam and the fourth sub-beam into a fourth beam, wherein the third sub-beam is light in the second sub-wavelength band and the fourth sub-beam is light in the third sub-wavelength band. The fifth filter is used to combine the third beam and the fourth beam into the first mixed beam, wherein the third beam is light in the first sub-wavelength band. The width of the third transition wavelength range of the fifth filter is smaller than the width of the fourth transition wavelength range of the sixth filter, and the first sub-wavelength band and the fourth transition wavelength range at least partially overlap.

[0041] Alternatively, in other examples, the aforementioned wavelength division component is used to receive the first mixed beam and to divide the first mixed beam into the first beam and the second sub-beam.

[0042] For example, the wavelength division component includes a first reflector, a second reflector, and an eighth filter. The eighth filter is used to split the first mixed beam into a first beam and a second sub-beam, guide the first beam to the first reflector, and guide the second sub-beam to the second reflector. The first reflector is used to reflect the first beam from the eighth filter back to the first filter. The second reflector is used to guide the second sub-beam from the eighth filter to the second filter.

[0043] In some examples of the aforementioned multiplexers or demultiplexers, the first wavelength band is a portion of the second transition wavelength range, and the sum of the width of the first wavelength band and the width of the first transition wavelength range is equal to the width of the second transition wavelength range. In other examples of the aforementioned multiplexers or demultiplexers, the first wavelength band completely overlaps with the second transition wavelength range. In still other examples of the aforementioned multiplexers or demultiplexers, the first wavelength band includes the second transition wavelength range. In these three examples, the light of the second transition wavelength range can be fully utilized, further improving the light utilization rate.

[0044] In some examples of the aforementioned multiplexers or demultiplexers, bandpass filter devices are bandpass filter diaphragms or wavelength division multiplexing (WDM) devices based on bandpass filter diaphragms. Edge-type filter devices are edge-type filter diaphragms or WDM devices based on edge-type filter diaphragms. Filter devices in the form of filter diaphragms can achieve light transmission using a spatial optical path; filter devices in the form of WDM devices can achieve light transmission using optical fiber connections.

[0045] In some examples of the aforementioned multiplexers or demultiplexers, the reflecting device is a reflecting prism. In other examples of the aforementioned multiplexers or demultiplexers, the reflecting device is a single mirror or a combination of at least two mirrors.

[0046] In another aspect, this application provides an optical communication device. The communication device includes a wavelength division unit and a wavelength multiplexing unit. The wavelength division unit includes at least one of the aforementioned wavelength division devices, and the wavelength multiplexing unit includes at least one of the aforementioned wavelength multiplexers. The wavelength multiplexing unit is used to combine multiple light beams output by the wavelength division unit. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of the structure of a wavelength division multiplexer provided in an embodiment of this application;

[0048] Figure 2 These are schematic diagrams of the filter spectra of bandpass and edge-type filter devices;

[0049] Figure 3This is a schematic diagram of the demultiplexing and combining process of the filtering device provided in the embodiments of this application;

[0050] Figure 4 This is a schematic diagram of another wavelength division multiplexer provided in an embodiment of this application;

[0051] Figure 5 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0052] Figure 6 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0053] Figure 7 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0054] Figure 8 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0055] Figure 9 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0056] Figure 10 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0057] Figure 11 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0058] Figure 12 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0059] Figure 13 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0060] Figure 14 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application;

[0061] Figure 15 This is a schematic diagram of a wave combiner provided in an embodiment of this application;

[0062] Figure 16 This is a schematic diagram of another type of multiplexer provided in this application embodiment;

[0063] Figure 17 This is a schematic diagram of another type of multiplexer provided in the embodiments of this application;

[0064] Figure 18 This is a schematic diagram of another type of multiplexer provided in the embodiments of this application;

[0065] Figure 19This is a schematic diagram of another type of multiplexer provided in the embodiments of this application;

[0066] Figure 20 This is a schematic diagram of another type of multiplexer provided in the embodiments of this application;

[0067] Figure 21 This is a schematic diagram of another type of multiplexer provided in the embodiments of this application;

[0068] Figure 22 This is a schematic diagram of another type of multiplexer provided in the embodiments of this application;

[0069] Figure 23 This is a schematic diagram of another type of multiplexer provided in the embodiments of this application;

[0070] Figure 24 This is a schematic diagram of another waveform combiner provided in the embodiments of this application;

[0071] Figure 25 This is a schematic diagram of the structure of the multiplexer provided in the embodiments of this application;

[0072] Figure 26 This is a schematic diagram of the structure of an optical communication device provided in an embodiment of this application;

[0073] Figure 27 This is a schematic diagram of the structure of another optical communication device provided in the embodiments of this application. Detailed Implementation

[0074] In optical communication systems, the 1260nm–1625nm wavelength range is considered a low-loss wavelength region. Light with wavelengths within this range is suitable for transmission in optical fibers. This wavelength region is divided into five bands: conventional (C) band, long-wavelength (L) band, short-wavelength (S) band, original (O) band, and extended (E) band.

[0075] Among them, the C-band exhibits the lowest loss, typically between 1530nm and 1565nm. The L-band has the second lowest loss, typically between 1565nm and 1625nm. The S-band typically ranges from 1460nm to 1530nm. The O-band typically ranges from 1260nm to 1360nm. The E-band typically ranges from 1360nm to 1460nm.

[0076] In this embodiment, the combination and splitting of light beams belonging to the 1260nm~1625nm band will be used as an example for illustration.

[0077] Figure 1This is a schematic diagram of a wavelength division multiplexer provided in an embodiment of this application. Figure 1 As shown, the wavelength division multiplexer includes a first filter element 10 and a second filter element 20. The first filter element 10 splits the input beam L0 into a first beam L1 and a second beam L2. The first beam L1 is light in a first wavelength band, and the second beam L2 includes light in a second wavelength band and light in a third wavelength band. The first wavelength band is located between the second and third wavelength bands. The second filter element 20 splits the second beam L2 into a first sub-beam L21 and a second sub-beam L22. The first sub-beam L21 is light in the second wavelength band, and the second sub-beam L22 is light in the third wavelength band. The width of the first transition wavelength range of the first filter element 10 is smaller than the width of the second transition wavelength range of the second filter element 20, and the first wavelength band and the second transition wavelength range at least partially overlap.

[0078] In this embodiment, the input beam first passes through a first filter, which separates the light of the first wavelength band from the input beam as the first beam. Then, a second filter further splits the light of other wavelength bands in the input beam, i.e., performs wave division processing on the second beam. Since the width of the first transition wavelength range of the first filter is smaller than the width of the second transition wavelength range of the second filter, and the first wavelength band and the second transition wavelength range at least partially overlap, at least a portion of the second transition wavelength range can still be used compared to the light corresponding to the entire second transition wavelength range being lost due to the second filter directly processing the input beam. This reduces the width of the wavelength range corresponding to the lost light and improves the utilization rate of the optical band corresponding to the input beam.

[0079] For example, the first filter device 10 is a bandpass filter device, such as a bandpass filter diaphragm. The second filter device is an edge filter device, such as an edge filter diaphragm.

[0080] Figure 2 Part (a) is a schematic diagram of the filter spectrum of a bandpass filter device. Figure 2 Part (b) is a schematic diagram of the filter spectrum of the edge-type filter device. Figure 2 The horizontal axis represents wavelength, which gradually increases from left to right; the vertical axis represents transmittance, which gradually increases from bottom to top.

[0081] like Figure 2 As shown in part (a), within the wavelength range of 1260 nm to 1630 nm, the bandpass filter allows light of wavelengths within the transmission wavelength range X1 to pass through, while reflecting light of wavelengths outside the transmission wavelength range, i.e., reflecting light of wavelengths within the wavelength ranges X2 and X3. The transmission spectrum shape of the bandpass filter is similar to a rectangular wave.

[0082] like Figure 2As shown in part (b), within the wavelength range of 1260 nm to 1630 nm, the edge-type filtering device divides the entire band into two parts: the transmission band Y1 corresponds to a longer wavelength, and the reflection band Y2 corresponds to a shorter wavelength. The shape of the transmission spectrum resembles a step. The transition wavelength range Y3 lies between the transmission band Y1 and the reflection band Y2.

[0083] The transmission wavelength range X1 of a bandpass filter can be set relatively narrow, and the falling edge of the filter can be designed to be very steep, meaning the transition wavelength range can be very small; therefore, it is not shown in the figure. In contrast, edge-type filters have wider transmission bands Y1 and Y2, resulting in a gentler falling edge, meaning the width of the transition wavelength range Y3 is larger. For example, for an edge-type filter where both the width of the transmission band Y1 and the width of the reflection band Y1 are greater than 40 nm, the width of the transition wavelength range Y3 is approximately 3 nm.

[0084] In this embodiment, a bandpass filter is used to transmit a first light beam and reflect a second light beam. That is, the wavelength range corresponding to the first light beam is the transmission wavelength range X1 of the bandpass filter, while the wavelength range corresponding to the second light beam includes wavelength ranges X2 and X3 located on either side of the transmission wavelength range X1. An edge filter is used to transmit a second sub-beam and reflect a first sub-beam. That is, the wavelength range corresponding to the second sub-beam is located in the transmission band Y1 of the edge filter, while the wavelength range corresponding to the first sub-beam is located in the reflection band Y2 of the edge filter.

[0085] Figure 3 Part (a) is a schematic diagram of the wavelength division process of the filtering device. For example... Figure 3 As shown in part (a), when the incident light includes both wavelengths within the transmission wavelength range and wavelengths outside the transmission wavelength range, the wavelengths within the transmission wavelength range are transmitted through the filter device, while the wavelengths outside the transmission wavelength range are reflected by the filter device, thus splitting the incident light into two paths: transmitted light and reflected light. The transmitted light propagates in the same direction as the incident light.

[0086] Figure 3 Part (b) is a schematic diagram of the combining process of the filtering device. For example... Figure 3 As shown in part (b), incident light 1 is light with a wavelength within the transmission wavelength range of the filter device, and incident light 2 is light with a wavelength within the reflection wavelength range of the filter device. When incident light 1 and incident light 2 are simultaneously incident on the filter device, the filter device transmits incident light 1 and reflects incident light 2. By controlling the incident position and angle of incident light 1 and incident light 2, incident light 1 and incident light 2 are combined into one outgoing light after passing through the filter device. The outgoing light has the same propagation direction as incident light 1.

[0087] It should be noted that, Figure 2Part (a) provides an exemplary description of the first filter using a bandpass filter. In other embodiments, the first filter may also be any other filter capable of splitting the input beam into a first beam and a second beam. For example, the first filter may be a bandstop filter that reflects light in the first band to obtain the first beam, and transmits light in the second band and the third band to obtain the second beam.

[0088] Figure 2 In section (b), a high-pass filter was used as an edge-type filter to illustrate the second filter. In other embodiments, the second filter can also be any other filter capable of splitting the second beam into a first sub-beam and a second sub-beam. For example, the second filter could be a low-pass filter, where the upper limit of the transmission wavelength range of the low-pass filter is less than the lower limit of the reflection wavelength range of the low-pass filter.

[0089] In some examples, the first band is part of the second transition wavelength range, and the sum of the width of the first band and the width of the first transition wavelength range equals the width of the second transition wavelength range. Thus, the upper limit wavelength of the second band is the lower limit wavelength of the second transition wavelength range, and the lower limit wavelength of the third band is the upper limit wavelength of the second transition wavelength range. This allows for the maximum utilization of light within the transition wavelength range of the second filter device without altering its filtering performance.

[0090] In other examples, the first band completely overlaps with the second transition wavelength range.

[0091] In other examples, the first band includes a second transition wavelength range, meaning the second transition wavelength range is a portion of the first band. In this case, the light lost in the demultiplexer is the light within the first transition wavelength range. Since the width of the first transition wavelength range is smaller than the width of the second transition wavelength range, the loss in the demultiplexer can be reduced. In the embodiments of this application, the width of the first wavelength can be set according to actual needs.

[0092] In some other examples, a portion of the first band overlaps with a portion of the second transition wavelength range.

[0093] It should be noted that, because the width of the first transition wavelength range is relatively small, Figure 3 It is not shown in the text.

[0094] In some examples, the width of the first transition wavelength range is no greater than 1 nm, for example, 0.8 nm. The width of the second transition wavelength range is approximately 3 nm.

[0095] In some examples, the input beam includes light from at least one of the following wavelength bands: S-band, C-band, L-band, O-band, and E-band. For example, the input beam includes light from the C-band, L-band, or S-band. Another example is that the input beam includes light from both the C-band and L-band. Yet another example is that the input beam includes light from all three wavelength bands: C-band, L-band, and S-band.

[0096] In other examples, the input beam is a portion of one of the five bands mentioned above, for example, a portion of the C band: 1530nm to 1560nm, etc.

[0097] In some other examples, the input beam is a portion of each of two adjacent bands from the five bands mentioned above. For example, it may include the larger wavelength region of the C band and the smaller wavelength region of the L band, etc.

[0098] In some examples, the first beam, the first sub-beam, and the second sub-beam are used separately, therefore, Figure 1 The demultiplexer also includes a first port and three second ports. The first port is used to receive the input beam. The three second ports are used to output the first beam, the first sub-beam, and the second sub-beam, respectively. In this example, the first beam, the first sub-beam, and the second sub-beam are output directly from their respective second ports.

[0099] In other examples, the first beam is first combined with the first sub-beam to obtain a first mixed beam, and then the first mixed beam and the second sub-beam are output from a second port respectively. In these examples, there are two second ports, one for outputting the first mixed beam and the other for outputting the second sub-beam.

[0100] In some other examples, the first beam and the first sub-beam are first combined to obtain a first mixed beam, then the first mixed beam is split, and the split beam and the second sub-beam are output from a second port respectively. In these examples, the number of second ports is equal to the number of beams obtained after splitting the first mixed beam plus one.

[0101] For example, in Figures 4 to 12 In this example, the structure and working principle of the wavelength division multiplexer are illustrated by taking the input beam as light with a wavelength range of 1524nm to 1627nm, the second wavelength range of 1524nm to 1572nm, the first wavelength range of 1572nm to 1575nm, the third wavelength range of 1575nm to 1627nm, and the second transition wavelength range of 1572nm to 1575nm.

[0102] Figure 4 This is a schematic diagram of another wavelength division multiplexer provided in an embodiment of this application. For example... Figure 4As shown, the wavelength division multiplexer includes a first filter element 10, a second filter element 20, and a multiplexing assembly. The first filter element 10 splits the input beam L0 into a first beam L1 and a second beam L2. The first beam L1 is light in a first wavelength band, and the second beam L2 includes light in a second wavelength band and light in a third wavelength band. The first wavelength band is located between the second and third wavelength bands. The second filter element 20 splits the second beam L2 into a first sub-beam L21 and a first sub-beam L22. The first sub-beam L21 is light in the second wavelength band, and the first sub-beam L22 is light in the third wavelength band. The multiplexing assembly combines the first beam L1 and the first sub-beam L21 into a first mixed beam L1'. The width of the first transition wavelength range of the first filter element 10 is smaller than the width of the second transition wavelength range of the second filter element 20, and the first wavelength band and the second transition wavelength range at least partially overlap.

[0103] The beam combiner includes a reflector 31. The reflector 31 is used to reflect a first sub-beam L21 to a first filter element 10. The first filter element 10 is also used to reflect the first sub-beam L21 from the reflector 31 to combine the first sub-beam L21 with the first beam L1 into a first mixed beam L1'.

[0104] For example, the reflecting device 31 is a reflecting prism. This reflecting prism is configured such that the absolute value of the difference between the first angle and the second angle is no greater than 3°, for example, no greater than 0.5°. The first angle is the angle between the incident path of the input beam L0 onto the first filter device 10 and the propagation path of the second beam L2 from the first filter device 10 to the second filter device 20. The second angle is the angle between the propagation path of the first sub-beam L21 from the reflecting device 31 to the first filter device 10 and the propagation path of the first sub-beam L21 after being reflected by the first filter device 10. This angular relationship allows the propagation path of the first sub-beam L21 after being reflected by the first filter device 10 to substantially coincide with the propagation path of the first beam L1 transmitted by the first filter device 10, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1'.

[0105] For example, the reflecting prism is a triangular reflecting prism, in which two connected surfaces are both reflecting surfaces (or total reflection surfaces), and a surface connecting the two reflecting surfaces (or total reflection surfaces) serves as both the incident surface and the exit surface.

[0106] like Figure 4 As shown, the splitter also includes a first port 81 and two second ports 82. The first port 81 is used to receive the input beam L0. One second port 82 is used to output the first mixed beam L1', and the other second port 82 is used to output the first sub-beam L22.

[0107] In some embodiments, the wavelength division multiplexer further includes a first fiber collimator 91 located at a first port 81 and a second fiber collimator 92 located at a second port 82. The input beam L0 passes through the first port 81, is collimated by the first fiber collimator 91, and then propagates to the first filter device 10. The first mixed beam L1' and the first sub-beam L22 are respectively output from their respective second ports 82 after passing through the second fiber collimator 92.

[0108] Exemplarily, the first fiber optic collimator 91 includes a tube 91a, a fiber optic connector 91b, and a collimating lens 91c. The fiber optic connector 91b and the collimating lens 91c are spaced apart within the tube 91a. The second fiber optic collimator 92 includes a tube 92a, a fiber optic connector 92b, and a collimating lens 92c. The fiber optic connector 92b and the collimating lens 92c are also spaced apart within the tube 92a.

[0109] The tube body, which can be made of plastic, glass, or metal, is used to integrate the corresponding fiber optic connectors and collimating lenses together to form a fiber optic collimator.

[0110] exist Figure 4 In the input beam L0, the light beam L0 is incident from the first fiber optic collimator 91 at the first port 81 and propagates to the first filter device 10. The first filter device 10 transmits light of the first wavelength band, thereby separating the first beam L1 from the input beam L0. The first filter device 10 reflects light of the second and third wavelength bands to form a second beam L2, and transmits the second beam L2 to the second filter device 20. The second filter device 20 transmits light of the third wavelength band to form a first sub-beam L22, and outputs the first sub-beam L22 from a second port 82 through the second fiber optic collimator 92. The second filter device 20 reflects the light of the second band to form a first sub-beam L21, and reflects the first sub-beam L21 to a reflecting prism. The reflecting prism guides the first sub-beam L21 to the first filter device 10. Since the first sub-beam L21 is light of the second band, the first filter device 10 reflects the first sub-beam L21 again, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1', which is then output from another second port 82 through the second fiber collimator 92.

[0111] In this embodiment, the input beam first passes through a first filter, which separates the light of the first wavelength band from the input beam as the first beam. Then, a second filter further splits the light of other wavelength bands in the input beam, i.e., performs wave division processing on the second beam. Since the width of the first transition wavelength range of the first filter is smaller than the width of the second transition wavelength range of the second filter, and the first wavelength band and the second transition wavelength range at least partially overlap, at least a portion of the second transition wavelength range can still be used compared to the light corresponding to the entire second transition wavelength range being lost due to the second filter directly processing the input beam. This reduces the width of the wavelength range corresponding to the lost light and improves the utilization rate of the optical band corresponding to the input beam.

[0112] Furthermore, multiplexing the first filtering component as part of the multiplexing assembly can reduce the number of optical components included in the demultiplexer, which is beneficial for reducing size and cost. In addition, the optical path structure is simple and easy to modulate and assemble.

[0113] Figure 5 This is a schematic diagram of another type of wavelength division multiplexer provided in an embodiment of this application. For example... Figure 5 As shown, this demultiplexer and Figure 4 The difference between the shown demultiplexers lies in the structure of the reflector 31 in the multiplexing assembly. Figure 5 In the illustrated embodiment, the reflecting device 31 includes two mirrors. These two mirrors are arranged symmetrically. The two mirrors are configured such that the absolute value of the difference between the first included angle and the second included angle is no greater than 3°, for example, no greater than 0.5°. The first included angle is the angle between the incident path of the input beam L0 onto the first filter device 10 and the propagation path of the second beam L2 from the first filter device 10 to the second filter device 20. The second included angle is the angle between the propagation path of the first sub-beam L21 from the reflecting device 31 to the first filter device 10 and the propagation path of the first sub-beam L21 after being reflected by the first filter device 10. This angular relationship allows the propagation path of the first sub-beam L21 after being reflected by the first filter device 10 to substantially coincide with the propagation path of the first beam L1 transmitted through the first filter device 10, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1'.

[0114] exist Figure 5In the input beam L0, the light beam L0 is incident from the first fiber optic collimator 91 at the first port 81 and propagates to the first filter device 10. The first filter device 10 transmits light of the first wavelength band, thereby separating the first beam L1 from the input beam L0. The first filter device 10 reflects light of the second and third wavelength bands to form a second beam L2, and transmits the second beam L2 to the second filter device 20. The second filter device 20 transmits light of the third wavelength band to form a second sub-beam L22, and outputs the second sub-beam L22 from a second port 82 through the second fiber optic collimator 92. The second filter device 20 reflects the light of the second band to form a first sub-beam L21, and reflects the first sub-beam L21 to a mirror. The mirror reflects the first sub-beam L21 to another mirror, which guides the first sub-beam L21 to the first filter device 10. Since the first sub-beam L21 is light of the second band, the first filter device 10 reflects the first sub-beam L21 again, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1', which is then output from another second port 82 through the second fiber collimator 92.

[0115] Figure 6 This is a schematic diagram of another wavelength division multiplexer provided in an embodiment of this application. Figure 4 and Figure 5 The difference in the illustrated embodiment lies in the different multiplexing components. Figure 6 In the illustrated embodiment, the beam combiner includes a reflector 31. The reflector 31 is used to reflect a first beam L1 to a first filter 10; the first filter 10 is also used to transmit the first beam L1 from the reflector 31 and reflect a first sub-beam L21 from the second filter 20, so as to combine the first sub-beam L21 and the first beam L1 into a first mixed beam L1'.

[0116] For example, the reflecting device 31 is a mirror. The reflecting surface of the mirror is arranged parallel to the filtering surface of the first filtering device 10, and the first filtering device 10 needs to be large enough so that the first beam L1 returning from the mirror can still pass through the first filtering device 10.

[0117] For example, the reflector 31 and the first filter 10 are configured such that the absolute value of the difference between any two of the first, second, and third included angles is no greater than 3°, for example, no greater than 0.5°. The first included angle is the angle between the first propagation path of the input beam L0 incident on the first filter 10 and the second propagation path of the second beam L2 from the first filter 10 to the second filter 20; the second included angle is the angle between the second propagation path and the third propagation path of the first sub-beam L21 from the second filter 20 to the first filter 10; and the third included angle is the angle between the third propagation path and the fourth propagation path of the second sub-beam L22 after reflection by the first filter 10.

[0118] In this embodiment, the absolute value of the difference between the fourth included angle and any one of the first to third included angles is no greater than 3°, for example, no greater than 0.5°. The fourth included angle is the angle between the incident path and the reflection path of the first beam L1 on the reflecting device 31.

[0119] exist Figure 6 In the input beam L0, the light beam L0 is incident from the first fiber collimator 91 at the first port 81 and propagates to the first filter device 10. The first filter device 10 transmits light of the first wavelength band, thereby separating the first beam L1 in the input beam L0 and transmitting the first beam L1 to the reflector 31, which reflects the first beam L1 back to the first filter device 10.

[0120] The first filter element 10 reflects the second and third band light to form a second beam L2, and transmits the second beam L2 to the second filter element 20. The second filter element 20 transmits the third band light to form a second sub-beam L22, and outputs the second sub-beam L22 from a second port 82 through the second fiber optic collimator 92. The second filter element 20 reflects the second band light to form a first sub-beam L21, and reflects the first sub-beam L21 back to the first filter element 10.

[0121] Since the first sub-beam L21 is light in the second band, the first filter device 10 reflects the first sub-beam L21 again and transmits the first beam L1 from the reflector device 31, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1', which is then output from another second port 82 through the second fiber collimator 92.

[0122] By reflecting and folding the second sub-beam using a reflective device, the optical path lengths of the first beam and the first sub-beam are made very close or even the same. This avoids coupling loss and phase difference caused by optical path difference, which helps to further reduce the loss of the demultiplexer.

[0123] Furthermore, multiplexing the first filtering component as part of the multiplexing assembly can reduce the number of optical components included in the demultiplexer, which is beneficial for reducing size and cost. In addition, the optical path structure is simple and easy to modulate and assemble.

[0124] Figure 7 This is a schematic diagram of another wavelength division multiplexer provided in an embodiment of this application. For example... Figure 7 As shown, this demultiplexer and Figure 6 The difference between the demultiplexers shown is that the structure of the reflector 31 in the multiplexing component is different.

[0125] Figure 7 In this design, the reflecting device 31 is a reflecting prism. Exemplarily, this reflecting prism is a triangular reflecting prism, where both connected surfaces are reflecting surfaces, and a surface connecting these two reflecting surfaces serves as both the incident and exit surface. This incident surface is parallel to the filtering surface of the first filtering device.

[0126] Compared to a mirror, using a reflecting prism can shorten the distance between the first filtering device and the reflecting device, effectively compressing the size along the entire optical path length, which is beneficial for device miniaturization.

[0127] Figure 7 The wavelength division process of the output beam by the filter shown is described in [reference needed]. Figure 6 The relevant details will not be elaborated upon here.

[0128] Figure 8 This is a schematic diagram of another type of wavelength division multiplexer provided in this application embodiment. Figure 8 The demultiplexer shown is Figure 4 and Figure 5 The difference between the demultiplexers shown lies in their multiplexing components. For example... Figure 8 As shown, the beam combiner includes a reflector 31 and a third filter 32. The reflector 31 reflects the first sub-beam L21 from the second filter 20 to the third filter 32. The third filter 32 transmits the first beam L1 from the first filter 10 and reflects the first sub-beam L21 from the reflector, so as to combine the first beam L1 and the first sub-beam L21 into a first mixed beam L1'.

[0129] For example, the reflective device 31 is a mirror, and the third filter device 32 is a bandpass filter device, such as a bandpass filter diaphragm.

[0130] exist Figure 8In the input beam L0, the light beam L0 is incident from the first fiber optic collimator 91 at the first port 81 and propagates to the first filter device 10. The first filter device 10 transmits light of the first wavelength band, thereby separating the first beam L1 from the input beam L0. The first filter device 10 reflects light of the second and third wavelength bands to form a second beam L2, and transmits the second beam L2 to the second filter device 20. The second filter device 20 transmits light of the third wavelength band to form a second sub-beam L22, and outputs the second sub-beam L22 from a second port 82 through the second fiber optic collimator 92. The second filter element 20 reflects the light of the second band to form a first sub-beam L21 and reflects the first sub-beam L21 to the reflector 31. The reflector 31 guides the first sub-beam L21 to the second filter element 20. The second filter element 20 transmits the first beam L1 from the first filter element 10 and reflects the first sub-beam L21 from the reflector 31, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1', which is then output from another second port 82 through the second fiber collimator 92.

[0131] The first filtering device is used for wave splitting, and the third filtering device is used for wave combining. Wave splitting and wave combining are implemented by two devices, which makes the position and structure of the devices more flexible and helps to reduce the difficulty of debugging.

[0132] Figure 9 This is a schematic diagram of another type of wavelength division multiplexer provided in this application embodiment. Figure 9 The demultiplexer shown is Figure 8 The difference between the demultiplexers shown lies in their multiplexing components. For example... Figure 9 As shown, the beam combiner includes a reflector 31 and a fourth filter 33. The reflector 31 reflects a first beam L1 from the first filter 10 to the fourth filter 33. The fourth filter 33 transmits the first beam L1 from the reflector 31 and reflects a first sub-beam L21 from the second filter 20, so as to combine the first beam L1 and the first sub-beam L21 into a first mixed beam L1'.

[0133] For example, the reflective device 31 is a mirror. The fourth filtering device 33 is a bandpass filter, such as a bandpass filter diaphragm.

[0134] exist Figure 9 In the input beam L0, the light beam L0 is incident from the first fiber collimator 91 at the first port 81 and propagates to the first filter device 10. The first filter device 10 transmits light of the first wavelength band, thereby separating the first beam L1 in the input beam L0 and outputting it to the reflector 31. The reflector 31 reflects the first beam L1 to the fourth filter device 33.

[0135] The first filter element 10 reflects the second and third band light to form a second beam L2, and transmits the second beam L2 to the second filter element 20. The second filter element 20 transmits the third band light to form a second sub-beam L22, and outputs the second sub-beam L22 from a second port 82 through the second fiber optic collimator 92. The second filter element 20 reflects the second band light to form a first sub-beam L21, and reflects the first sub-beam L21 to the fourth filter element 33.

[0136] The fourth filter device 33 transmits the first beam L1 from the reflector 31 and reflects the first sub-beam L21 from the second filter device 20, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1', which is then output from another second port 82 through the second fiber collimator 92.

[0137] In this embodiment, the propagation paths of the first beam from the first filter device to the reflecting device, the first beam from the reflecting device to the fourth filter device, the first sub-beam from the first filter device to the second filter device, and the first sub-beam from the second filter device to the fourth filter device are arranged in a parallelogram. This reduces the optical path difference between the second sub-beam and the first beam, further reducing the optical loss of the device.

[0138] In optical communication systems, isolation refers to the isolation of return light (i.e., light transmitted in the opposite direction) or light of the corresponding wavelength in other channels. In this application embodiment, the isolation is improved by increasing the transmission loss of the light that needs to be isolated.

[0139] Optionally, in order to improve isolation, the wavelength division multiplexer provided in this application embodiment further includes at least one intermediate filter device, which is used for at least one of the following: guiding a second beam from a first filter to a second filter, guiding a first sub-beam from the second filter device to a fourth filter device, and outputting a second sub-beam from the second filter device.

[0140] The position and number of intermediate filters can be set according to actual needs, as long as the designed isolation level and the guidance of the corresponding sub-beams are met. The following section combines... Figure 10 An illustrative example of the arrangement of intermediate filters is provided.

[0141] Figure 10 This is a schematic diagram of another type of wavelength division multiplexer provided in an embodiment of this application. For example... Figure 10 As shown, the demultiplexer includes a first filter element 10, a second filter element 20, a fourth filter element 33, a reflector 31, and three intermediate filter elements. For a description of the first filter element 10, the second filter element 20, the fourth filter element 33, and the reflector 31, please refer to [link to relevant descriptions]. Figure 9Related content.

[0142] The three intermediate filter devices are a first intermediate filter device 41, a second intermediate filter device 42, and a third intermediate filter device 43. The first intermediate filter device 41 is located in the propagation path of the second beam L2 output from the first filter device 10, and is used to reflect the second beam L2 back to the second filter device 20. Exemplarily, the first intermediate filter device 41 is a bandpass filter diaphragm. The second intermediate filter device 42 is located in the propagation path of the second sub-beam L22 output from the second filter device 20, and is used to transmit the second sub-beam L22. Exemplarily, the second intermediate filter device 42 is an edge filter diaphragm. The third intermediate filter device 43 is located in the propagation path of the first sub-beam L21 output from the second filter device 20, and is used to reflect the first sub-beam L21 back to the fourth filter device 33. Exemplarily, the third intermediate filter device 43 is an edge filter diaphragm.

[0143] The following is about Figure 10 The wavelength division process of the waveform divider shown is explained in detail.

[0144] exist Figure 10 In the input beam L0, the light beam L0 is incident from the first fiber collimator 91 at the first port 81 and propagates to the first filter device 10. The first filter device 10 transmits light of the first wavelength band, thereby separating the first beam L1 in the input beam L0 and outputting it to the reflector 31. The reflector 31 reflects the first beam L1 to the fourth filter device 33.

[0145] The first filter element 10 reflects the second and third band light to form a second beam L2, and transmits the second beam L2 to the first intermediate filter element 41. The first intermediate filter element 41 reflects the second beam L2 so that the second beam L2 propagates to the second filter element 20. The second filter element 20 transmits the third band light to form a second sub-beam L22, and outputs the second sub-beam L22 to the second intermediate filter element 42, which transmits the second sub-beam L22 so that the second sub-beam L22 is output from a second port 82 through the second fiber collimator 92. The second filter element 20 reflects the second band light to form a first sub-beam L21, and reflects the first sub-beam L21 to the third intermediate filter element 43, which reflects the first sub-beam L21 to the fourth filter element 33.

[0146] The fourth filter device 33 transmits the first beam L1 from the reflector 31 and reflects the first sub-beam L21 from the third intermediate filter device 43, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1', which is then output from another second port 82 through the second fiber collimator 92.

[0147] In this embodiment, the light in the corresponding wavelength bands of the second beam L2, the first beam L1, the first sub-beam L21, and the second sub-beam L22 all pass through two filter films, significantly improving the isolation. Testing showed that... Figure 10 The illustrated embodiment achieves an isolation level of over 30 dB.

[0148] Figure 11 This is a schematic diagram of another type of wavelength division multiplexer provided in an embodiment of this application. For example... Figure 11 As shown, this demultiplexer is in Figure 9 The demultiplexer shown has been modified by adding a fifth filter element 50 and a sixth filter element 60.

[0149] The fifth filtering device 50 is used to split the first mixed beam L1' into a third beam L3 and a fourth beam L4. The third beam L3 is light from the first sub-band, and the fourth beam L4 includes light from the second and third sub-bands. The first sub-band is located between the second and third sub-bands. As previously mentioned, the first mixed beam L1' includes light from the first and second bands, and the first, second, and third sub-bands satisfy the following relationships: the first sub-band belongs to the second band; the second sub-band includes the portion of the first and second bands located between the first band and the first sub-band; and the third sub-band belongs to the second band.

[0150] The sixth filter device 60 is used to divide the fourth beam L4 into a third sub-beam L41 and a fourth sub-beam L42, where the third sub-beam L41 is light from the second sub-wavelength band and the second sub-beam L42 is light from the third sub-wavelength band. The width of the third transition wavelength range of the fifth filter device 50 is smaller than the width of the fourth transition wavelength range of the sixth filter device 60, and the first sub-wavelength band and the fourth transition wavelength range at least partially overlap.

[0151] For example, the first band (the band corresponding to the first beam L1) is 1521nm to 1524nm. The second band (the band corresponding to the first sub-beam L21) is 1524nm to 1627nm. The third band (the band corresponding to the second sub-beam L22) is 1476nm to 1521nm. Correspondingly, the band corresponding to the second beam L2 includes 1476nm to 1521nm and 1524nm to 1627nm. The band corresponding to the first mixed beam L1' includes 1521nm to 1524nm and 1524nm to 1627nm, that is, 1521nm to 1627nm.

[0152] The first sub-band (the band corresponding to the third beam L3) is 1572nm–1575nm. The second sub-band (the band corresponding to the fourth sub-beam L42) includes 1521nm–1524nm and 1524nm–1572nm, i.e., 1521nm–1572nm. The third sub-band (the band corresponding to the third sub-beam L41) is 1575nm–1627nm. Correspondingly, the band corresponding to the fourth beam L4 includes 1524nm–1572nm and 1575nm–1627nm. The band corresponding to the first mixed beam L1' includes 1572nm–1575nm and 1575nm–1627nm, i.e., 1572nm–1627nm.

[0153] For example, the fifth filter device 50 is a bandpass filter device, such as a bandpass filter diaphragm. The sixth filter device 60 is an edge filter device, such as an edge filter diaphragm.

[0154] Optionally, the splitter also includes another multiplexing component 70 for combining the third beam L3 and the third sub-beam L41 into a second hybrid beam L2'.

[0155] Exemplarily, the other beam combiner 70 includes another reflector 71 and a seventh filter 72. The other reflector 71 is used to reflect the third beam L3 from the fifth filter 50 to the seventh filter 72. The seventh filter 72 is used to transmit the third beam L3 and reflect the third sub-beam L41 from the sixth filter 60 to combine the third beam L3 and the third sub-beam L41 into a second mixed beam L2'.

[0156] For example, the seventh filtering device 72 is a bandpass filtering device, such as a bandpass filter diaphragm.

[0157] The following is about Figure 11 The wave splitting process of the wave splitter shown will be explained.

[0158] exist Figure 11 In the input beam L0, the light beam L0 is incident from the first fiber collimator 91 at the first port 81 and propagates to the first filter device 10. The first filter device 10 transmits light of the first wavelength band, thereby separating the first beam L1 in the input beam L0 and outputting it to the reflector 31. The reflector 31 reflects the received first beam L1 to the fourth filter device 33.

[0159] The first filter element 10 reflects the second and third band light to form a second beam L2, and transmits the second beam L2 to the second filter element 20. The second filter element 20 transmits the third band light to form a second sub-beam L22, and outputs the second sub-beam L22 from a second port 82. The second filter element 20 reflects the second band light to form a first sub-beam L21, and reflects the first sub-beam L21 to the fourth filter element 33.

[0160] The fourth filter 33 transmits the first beam L1 from the reflector 31 and reflects the first sub-beam L21 from the second filter 20, thereby combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1', and propagating the first mixed beam L1' to the fifth filter 50.

[0161] The fifth filter device 50 transmits light from the first sub-band, thereby separating the third beam L3 from the first mixed beam L1' and outputting it to the reflector 71. The reflector 71 reflects the received third beam L3 to the seventh filter device 72.

[0162] The fifth filter device 50 reflects the light from the second and third sub-bands to form a fourth beam L4, and transmits the fourth beam to the sixth filter device 60. The sixth filter device 60 transmits the light from the third sub-band to form a fourth sub-beam L42, and outputs the fourth sub-beam L42 from a second port 82. The sixth filter device 60 reflects the light from the second sub-band to form a third sub-beam L41, and reflects the third sub-beam L41 to the seventh filter device 72.

[0163] The seventh filter device 33 transmits the third beam L3 from the reflector 71 and reflects the third sub-beam L41 from the sixth filter device 60, thereby combining the third sub-beam L41 and the third beam L3 into a second mixed beam L2', and outputs the second mixed beam L2' from another second port 82.

[0164] In this embodiment, a second sub-beam L22, a fourth sub-beam L42, and a second mixed beam L2' are output from three second ports 82, respectively, and the second sub-beam L22, the fourth sub-beam L42, and the second mixed beam L2' correspond to light in different wavelength bands. Therefore, the wavelength division multiplexer provided in this embodiment can achieve separation of three wavelength bands.

[0165] It should be noted that, in Figure 4 , Figure 5 , Figure 8 and Figure 10 In the illustrated embodiment, one second port 82 is on the same side as the first port 81, and the other second port 82 is on the opposite side of the first port 81. Figure 6 , Figure 7 and Figure 9 In the illustrated embodiment, both second ports 82 are on the same side as the first port 81. When the first port 81 and the second port 82 are on the same side, optical fibers can be output in the same direction, which allows the size of the splitter to be significantly reduced.

[0166] In addition, Figure 6 , Figure 7 and Figure 9 In the embodiment shown, the first fiber collimator 91 and the second fiber collimator 92 are set independently of each other.

[0167] In other examples, when the first port 81 and the second port 82 are on the same side, the first fiber collimator 91 and the second fiber collimator 92 can be integrated together using a collimator array to further reduce the size of the demultiplexer.

[0168] In addition, Figure 1 , Figures 4 to 11 In the illustrated embodiment, the optical components within the wavelength division multiplexer propagate the light beam via spatial optical paths. In other embodiments, the optical components within the wavelength division multiplexer can also propagate the light beam through cascading, for example... Figure 12 The wave demultiplexer shown.

[0169] Figure 12 This is a schematic diagram of another type of wavelength division multiplexer provided in an embodiment of this application. For example... Figure 12 As shown, the demultiplexer includes a first filter element 10 and a second filter element 20. Both the first filter element 10 and the second filter element 20 are three-port wavelength division multiplexing (WDM) devices. The first filter element 10 is a bandpass filter element, fabricated based on a bandpass filter diaphragm. The second filter element 20 is an edge filter element, fabricated based on an edge filter diaphragm. The functions of the first and second filter elements are described in [reference needed]. Figure 1 Related embodiments are omitted in detail here.

[0170] like Figure 12As shown, the first filtering device 10 includes a housing 11, a first tube 12, a first fiber optic connector 13, a collimating lens 14, a bandpass filter diaphragm 15, a second tube 16, a collimating lens 17, and a second fiber optic connector 18. The first fiber optic connector 13 is a dual-fiber connector, including a common end connector and a reflective end connector. The first fiber optic connector 13 and the collimating lens 14 are located within the first tube 12. The first fiber optic connector 13 is located at one end of the collimating lens 14, and an air gap exists between them. The bandpass filter diaphragm 15 is fixed to the other end of the collimating lens 14. The collimating lens 17 and the second fiber optic connector 18 are located within the second tube 16, and an air gap exists between them. The collimating lens 17 is opposite to the bandpass filter diaphragm 15. The second fiber optic connector 18 is a single-fiber connector.

[0171] For example, the housing 11 is a glass tube or a metal tube, etc. The collimating lens 14 is a conventional lens (C-lens) (also known as a spherical lens or C-lens) or a gradient-index (GRIN) lens (also known as a self-focusing lens and G-lens).

[0172] The structure of the second filter device 20 is basically the same as that of the first filter device; only the bandpass filter diaphragm 15 needs to be replaced with an edge filter diaphragm.

[0173] The reflective end of the first fiber optic connector 13 of the first filter device 10 and the common end of the first fiber optic connector 13 of the second filter device 20 are connected by optical fiber. An input beam is incident through the common end of the first fiber optic connector 13 of the first filter device 10, and a bandpass filter diaphragm 15 splits the input beam into a first beam and a second beam. The first beam passes through the bandpass filter diaphragm 15, passes through the collimating lens 17, and is output through the second fiber optic connector 18.

[0174] The second beam is incident on the second filter device 20 from the reflective end of the first fiber optic connector 13 of the first filter device 10 and the common end of the first fiber optic connector 13 of the second filter device 20. The edge-type filter diaphragm of the second filter device 20 splits the second beam into a first sub-beam and a second sub-beam. The first sub-beam is output from the second fiber optic connector of the second filter device 20, and the second sub-beam is output from the reflective end of the first fiber optic connector of the second filter device 20.

[0175] Optionally, such as Figure 12As shown, the splitter also includes a third filter element 32, whose structure is the same as that of the first filter element 10. The reflective end connector of the first fiber optic connector of the third filter element 32 is connected to the second fiber optic connector of the second filter element 20 via optical fiber, receiving the second sub-beam output from the second fiber optic connector of the second filter element 20. The second fiber optic connector of the third filter element 32 is connected to the second fiber optic connector of the first filter element 10, receiving the first sub-beam output from the second fiber optic connector of the first filter element 10. The bandpass filter diaphragm of the third filter element 32 combines the first sub-beam and the first beam into a first mixed beam, which is then output from the common end connector of the first fiber optic connector of the third filter element 32.

[0176] Figures 4 to 12 The embodiments shown are all illustrated using the example of a beam combiner combining the first sub-beam L21 and the first beam L1 into a first mixed beam L1'. Alternatively, in other embodiments, for example... Figure 13 and Figure 14 In the embodiment shown, the beam combiner combines the second sub-beam and the first beam into a first hybrid beam.

[0177] Figure 13 This is a schematic diagram of another type of wavelength division multiplexer provided in the embodiments of this application. Figure 14 This is a schematic diagram of another type of wavelength division multiplexer provided in an embodiment of this application. For example... Figure 13 and Figure 14 As shown, the beam combiner includes a first reflector 31a, a second reflector 31b, and an eighth filter 34. The first reflector 31a reflects a first beam L1 from the first filter 10 to the eighth filter 34. The second reflector 31b reflects a second sub-beam L22 from the second filter 20 to the eighth filter 34. The eighth filter 34 transmits the first beam L1 from the first reflector 31a and reflects the second sub-beam from the second reflector 31b to combine the first beam L1 and the second sub-beam L22 into a first mixed beam L1'.

[0178] For example, both the first reflecting device 31a and the second reflecting device 31b are reflectors. The eighth filtering device 34 is a bandpass filtering device, such as a bandpass filter diaphragm.

[0179] It should be noted that, Figure 13 exist Figure 5 Based on this, it is obtained by adjusting the position of the reflective device and adding filter devices. Figure 14 exist Figure 9 This is achieved by adding reflective devices and adjusting the positions of filter components. For Figures 4-11The wave demultiplexers shown can all change the multiplexing component to combine the second sub-beam and the first beam into a first mixed beam by at least one of the following methods: changing the number and / or position of the reflective devices; and changing the number and / or position of the filtering devices, etc.

[0180] Figure 15 This is a schematic diagram of a combiner provided in an embodiment of this application. Figure 15 As shown, the combiner includes a first filter element 10 and a second filter element 20. The second filter element 20 combines a first sub-beam L21 and a second sub-beam L22 into a second beam, where the first sub-beam L21 is light in a second wavelength band and the second sub-beam L22 is light in a third wavelength band. The first filter element 10 combines a first beam L1 and a second beam L2 into an output beam L0, where the first beam L1 is light in a first wavelength band, located between the second and third wavelength bands. The width of the first transition wavelength range of the first filter element 10 is smaller than the width of the second transition wavelength range of the second filter element 20, and the first wavelength band and the second transition wavelength range at least partially overlap.

[0181] Figure 16 This is a schematic diagram of another type of combiner provided in an embodiment of this application. For example... Figure 16 As shown, the multiplexer includes a first filter element 10, a second filter element 20, and a demultiplexer assembly. For a description of the first filter element 10 and the second filter element 20, please refer to [link to relevant description]. Figure 15 The relevant content is as follows. The wavelength division component is used to receive the first mixed beam L1' and to divide the first mixed beam L1' into a first beam L1 and a first sub-beam L21.

[0182] Since the first mixed beam L1' contains light in the first wavelength band, and the first wavelength band at least partially overlaps with the second transition wavelength range of the second filter device 20, if the first mixed beam L1' and the second sub-beam L22 are directly input into the second filter device 20 for combining, the portion of the first wavelength band that overlaps with the second transition wavelength range will be lost. In this embodiment, the light in the first wavelength band (i.e., the first beam L1) is first separated from the first mixed beam L1' by the wavelength division component, and then the remaining first sub-beam L21 and second sub-beam L22 are combined into the second beam L2 by the second filter device 20. Finally, the first beam L1 and the second beam L2 are combined into the output beam L0 by the first filter device 10. In this way, the light in the second wavelength range that overlaps with the first wavelength band can still pass through the wavelength division device and can be utilized, thus improving the utilization rate of the optical wavelength band.

[0183] For example, the wavelength division component includes a reflector 31 and a first filter 10. The first filter 10 is further configured to divide the first mixed beam L1' into a first beam L1 and a first sub-beam L21, and to reflect the first sub-beam L21 to the reflector 31; the reflector 31 is configured to reflect the first sub-beam L21 to a second filter 20, so that the second filter 20 can combine the received first sub-beam L21 and second sub-beam L22 into a second beam L2.

[0184] In some examples, the first mixed beam L1' is based on the aforementioned Figures 4 to 12 The first mixed beam L1' output from any provided splitter is obtained, for example, by amplifying the power of the first mixed beam L1' output from the aforementioned splitter.

[0185] The following is about Figure 16 The multiplexing process of the multiplexer shown is explained in detail.

[0186] exist Figure 16 In this process, the first filter device 10 receives a first mixed beam L1' from a second port, transmits light of the first wavelength band and reflects light of the first sub-wavelength band, thereby splitting the first mixed beam L1' into a first beam L1 (light of the first wavelength band) and a first sub-beam L21 (light of the first sub-wavelength band). The first filter device 10 propagates the first sub-beam L21 to a reflector 31, which reflects the first sub-beam L21 from the first filter device 10 to a second filter device 20. The second filter device 20 reflects the first sub-beam L21 from the first filter device 10 and transmits a second sub-beam L22 from another second port, thereby combining the first sub-beam L21 and the second sub-beam L22 into a second beam L2, which is then output to the first filter device 10. The first filter device 10 reflects the second beam L2 from the second filter device 20 and combines the second beam L2 with the first beam L1 into an output beam L0, which is then output from the first port.

[0187] It should be noted that, Figure 16 The wave combiner shown Figure 4 The device structures of the demultiplexers shown are the same. Figure 16 The multiplexing process of the multiplexer shown is: Figure 4 The reverse process of the wavelength division process of the waveform divider shown.

[0188] Figure 17 This is a schematic diagram of another type of combiner provided in the embodiments of this application. Figure 17 The wave combiner shown Figure 16 The difference between the wave combiners shown lies in the different structures of the reflector 31 and the different relative positions of the devices. Figure 17 The multiplexing process of the multiplexer shown is described in [reference]. Figure 16The relevant content will not be described in detail here.

[0189] In addition, it should be noted that, Figure 17 The wave combiner shown Figure 5 The device structures of the demultiplexers shown are the same. Figure 17 The multiplexing process of the multiplexer shown is: Figure 5 The reverse process of the wavelength division process of the waveform divider shown.

[0190] Figure 18 This is a schematic diagram of another type of multiplexer provided in an embodiment of this application. Figure 16 and Figure 17 The difference between the multiplexers shown lies in the structure of the demultiplexing components. For example... Figure 18 As shown, the wavelength division multiplexing assembly includes a reflector 31 and a first filter 10. The first filter 10 is further configured to split the first mixed beam L1' into a first beam L1 and a first sub-beam L21, guide the first beam L1 to the reflector 31, and reflect the first sub-beam L21 to the second filter 20. The reflector 31 is configured to reflect the first beam L1 to the first filter 10, and the first filter 10 transmits the first beam L1 from the reflector 31.

[0191] For example, the reflector and the first filter element 10 are configured such that the absolute value of the difference between any two of the first, second, and third included angles is no greater than 3°, for example, no greater than 0.5°. The first included angle is the angle between the first propagation path of the output beam L0 and the second propagation path of the second beam L2 from the second filter element 20 to the first filter element 10; the second included angle is the angle between the second propagation path and the third propagation path of the first sub-beam L21 from the first filter element 10 to the second filter element 20; and the third included angle is the angle between the third propagation path and the fourth propagation path of the first mixed beam L1' incident on the first filter element 10.

[0192] The following is about Figure 18 The multiplexing process of the multiplexer shown is explained in detail.

[0193] exist Figure 18 In the process, the first filter device 10 receives a first mixed beam L1' from a second port, transmits light of the first wavelength band and reflects light of the first sub-wavelength band, thereby splitting the first mixed beam L1' into a first beam L1 (light of the first wavelength band) and a first sub-beam L21 (light of the first sub-wavelength band). The first filter device 10 transmits the separated first beam L1 to a reflector 31, and the reflector 31 reflects the first beam L1 from the first filter device 10 back to the first filter device 10. The first filter device 10 then transmits the first beam L1 from the emitting device.

[0194] The first filter element 10 also reflects the separated first sub-beam L21 to the second filter element 20. The second filter element 20 reflects the first sub-beam L21 from the first filter element 10 and transmits the second sub-beam L22 from another second port, thereby combining the first sub-beam L21 and the second sub-beam L22 into a second beam L2, which is then output to the first filter element 10. The first filter element 10 reflects the second beam L2 from the second filter element 20 and combines the second beam L2 with the first beam L1 from the reflector 31 into an output beam L0, which is then output from the first port.

[0195] In addition, it should be noted that, Figure 18 The wave combiner shown Figure 6 The device structures of the demultiplexers shown are the same. Figure 18 The multiplexing process of the multiplexer shown is: Figure 6 The reverse process of the wavelength division process of the waveform divider shown.

[0196] Figure 19 This is a schematic diagram of another type of combiner provided in the embodiments of this application. Figure 19 The wave combiner shown is Figure 18 The difference in the wave combiners shown lies in the different reflector 31. Figure 19 In the middle, the reflecting device 31 is a reflecting prism. Figure 19 The multiplexing process of the multiplexer is shown in the following figure. Figure 18 Related content.

[0197] In addition, it should be noted that, Figure 19 The wave combiner shown Figure 7 The device structures of the demultiplexers shown are the same. Figure 19 The multiplexing process of the multiplexer shown is: Figure 7 The reverse process of the wavelength division process of the waveform divider shown.

[0198] Figure 20 This is a schematic diagram of another type of combiner provided in the embodiments of this application. Figure 20 The wave combiner shown is Figure 16 and Figure 17 The difference between the shown demultiplexers lies in their demultiplexing components. For example... Figure 20 As shown, the wavelength division multiplexing assembly includes a reflector 31 and a third filter. The third filter is used to split the first mixed beam L1' into a first beam L1 and a first sub-beam L21, guide the first beam L1 to the first filter 10, and guide the first sub-beam L21 to the reflector 31. The reflector 31 is used to reflect the first sub-beam L21 from the third filter to the second filter 20.

[0199] The following is about Figure 20 The multiplexing process of the multiplexer shown is explained in detail.

[0200] exist Figure 20 In this process, a fourth filter receives a first mixed beam L1' from a second port, transmits light from the first wavelength band, and reflects light from the first sub-wavelength band, thereby splitting the first mixed beam L1' into a first beam L1 (light from the first wavelength band) and a first sub-beam L21 (light from the first sub-wavelength band). The fourth filter guides the first beam L1 to the first filter 10 and the first sub-beam L21 to the reflector 31. The reflector 31 reflects the first sub-beam L21 from the fourth filter to the second filter 20. The second filter 20 reflects the first sub-beam L21 from the reflector 31 and transmits a second sub-beam L22 from another second port, thereby combining the first sub-beam L21 and the second sub-beam L22 into a second beam L2, which is then output to the first filter 10. The first filter 10 reflects the second beam L2 from the second filter 20 and transmits the first beam L1 from the fourth filter, thereby combining the second beam L2 and the first beam L1 into an output beam L0, which is then output from the first port.

[0201] It should be noted that, Figure 20 The wave combiner shown Figure 8 The device structures of the demultiplexers shown are the same. Figure 20 The multiplexing process of the multiplexer shown is: Figure 8 The reverse process of the wavelength division process of the waveform divider shown.

[0202] Figure 21 This is a schematic diagram of another type of combiner provided in the embodiments of this application. Figure 21 The wave combiner shown is Figure 20 The difference between the shown demultiplexers lies in their demultiplexing components. For example... Figure 21 As shown, the wavelength division component includes a reflector and a fourth filter element. The fourth filter element is used to divide the first mixed beam L1' into a first beam L1 and a first sub-beam L21, guide the first beam L1 to a reflector 31, and guide the first sub-beam L21 to a second filter element 20. The reflector 31 is used to reflect the first beam L1 from the fourth filter element to the first filter element 10.

[0203] For example, the propagation paths of the first beam L1 from the fourth filter to the reflector 31, the propagation paths of the first beam L1 from the reflector 31 to the first filter 10, the propagation paths of the first sub-beam L21 from the fourth filter to the second filter 20, and the propagation paths of the first sub-beam L21 from the second filter 20 to the first filter 10 are arranged in a parallelogram.

[0204] exist Figure 21 In the process, the fourth filter receives the first mixed beam L1' from a second port, transmits light of the first wavelength band and reflects light of the first sub-wavelength band, thereby splitting the first mixed beam L1' into a first beam L1 (light of the first wavelength band) and a first sub-beam L21 (light of the first sub-wavelength band). The fourth filter transmits the first beam L1 to the reflector 31, the reflector 31 reflects the first beam L1 from the fourth filter to the first filter 10, and the first filter 10 transmits the first beam L1 from the transmitter.

[0205] The fourth filter also reflects the first sub-beam L21 to the second filter 20. The second filter 20 reflects the first sub-beam L21 from the fourth filter and transmits the second sub-beam L22 from another second port, thereby combining the first sub-beam L21 and the second sub-beam L22 into a second beam L2, which is then output to the first filter 10. The first filter 10 reflects the second beam L2 from the second filter 20 and combines it with the first beam L1 from the reflector 31 into an output beam L0, which is then output from the first port.

[0206] It should be noted that, Figure 21 The wave combiner shown Figure 9 The device structures of the demultiplexers shown are the same. Figure 21 The multiplexing process of the multiplexer shown is: Figure 9 The reverse process of the wavelength division process of the waveform divider shown.

[0207] In some examples, to improve device isolation, the multiplexer further includes at least one intermediate filter element, which is used to perform at least one of the following: guiding a first sub-beam L21 from a fourth filter element to a second filter element 20, guiding a first sub-beam L21 from the second filter element 20 to a first filter element 10, and guiding a second sub-beam L22 to the second filter element 20. The at least one intermediate filter element includes at least one of an edge-type filter element and a bandpass filter element.

[0208] Figure 22 This is a schematic diagram of another type of combiner provided in the embodiments of this application. For example... Figure 22As shown, the beam combiner includes a first filter element 10, a second filter element 20, a fourth filter element, a reflector, and three intermediate filter elements. These three intermediate filter elements are the first intermediate filter element, the second intermediate filter element, and the third intermediate filter element. The first intermediate filter element is located in the propagation path of the second beam L2 output from the second filter element 20, and is used to reflect the second beam L2 back to the first filter element 10. The second intermediate filter element is located in the propagation path of the second sub-beam L22 propagating to the second filter element 20, and is used to transmit the second sub-beam L22. The third intermediate filter element is located in the propagation path of the first sub-beam L21 output from the fourth filter element, and is used to reflect the first sub-beam L21 back to the second filter element 20.

[0209] Figure 22 The multiplexing process of the multiplexer shown is similar to... Figure 21 The multiplexing process of the multiplexer shown is similar and will not be described in detail here. It should be noted that... Figure 22 The wave combiner shown Figure 10 The device structures of the demultiplexers shown are the same. Figure 22 The multiplexing process of the multiplexer shown is: Figure 10 The reverse process of the wavelength division process of the waveform divider shown.

[0210] Figure 23 This is a schematic diagram of another type of combiner provided in the embodiments of this application. For example... Figure 23 As shown, the combiner and Figure 11 The device structures of the demultiplexers shown are the same. Figure 23 The multiplexing process of the multiplexer shown is: Figure 11 The reverse process of the wavelength division process of the waveform divider shown is not described in detail here.

[0211] This application embodiment also provides a multiplexer, the structure of which is similar to... Figure 12 The demultiplexers shown have the same structure, and the multiplexing process is as follows: Figure 12 The reverse process of the wavelength division process of the waveform divider shown is not described in detail here.

[0212] Alternatively, in some examples, a wavelength division multiplexing (WDM) component can be used to receive a first mixed beam and to split the first mixed beam into a first beam and a second sub-beam. For example Figure 24 and Figure 25 The illustrated embodiment.

[0213] Figure 24 and Figure 25 These are schematic diagrams of another type of combiner provided in the embodiments of this application. Figure 24 and 25 As shown, the wavelength division multiplexing (WDM) assembly includes a first reflector 31a, a second reflector 31b, and an eighth filter 34.

[0214] The eighth filter element 34 is used to receive the first mixed beam L1', split the first mixed beam L1' into a first beam L1 and a second sub-beam L22, guide the first beam L1 to a first reflector 31a, and guide the second sub-beam L22 to a second reflector 31b. The first reflector 31a is used to reflect the first beam L1 from the eighth filter element 34 to the first filter element 10. The second reflector 31b is used to guide the second sub-beam L22 from the eighth filter element 34 to the second filter element 20.

[0215] It should be noted that, Figure 24 The wave combiner shown Figure 13 The device structures of the demultiplexers shown are the same. Figure 24 The multiplexing process of the multiplexer shown is: Figure 13 The reverse process of the wavelength division process of the waveform divider shown is not described in detail here. Figure 25 The wave combiner shown Figure 14 The device structures of the demultiplexers shown are the same. Figure 25 The multiplexing process of the multiplexer shown is: Figure 14 The reverse process of the wavelength division process of the waveform divider shown is not described in detail here.

[0216] This application also provides an optical communication device. For example... Figure 26 As shown, the communication device includes a wavelength division unit and a wavelength combination unit. The wavelength division unit includes at least one of the aforementioned wavelength division devices 1, and the wavelength combination unit includes one of the aforementioned wavelength combination devices 2. The wavelength combination unit is used to combine multiple beams output by the wavelength division unit.

[0217] In some examples, other optical communication devices, such as optical amplifiers (OAs), are also present between the multiplexing unit and the demultiplexing unit. The OA is used to amplify the power of light in the corresponding wavelength band. In this case, multiple beams output from the demultiplexing unit are processed by other optical communication devices, and then the multiplexing unit combines the processed beams.

[0218] Since the wavelength division multiplexer 1 provided in this application embodiment is suitable for separating different wavelength bands, for example Figure 26 In this process, band 1 and band 2 are separated, so it can be called an optical band splitter. Similarly, a multiplexer can also be called an optical band multiplexer.

[0219] For example, the communication device is suitable for broadband optical communication systems, such as C-band + L-band, S-band + C-band + L-band, and S-band + C-band.

[0220] This application also provides an optical communication device. The optical communication device includes multiple multiplexers. These multiplexers are divided into at least two stages. In the first stage, the two second ports of each multiplexer are respectively connected to a laser or an optical amplifier. The two second ports of multiplexers outside the first stage are respectively connected to the first ports of two multiplexers in the previous stage, or connected to the first port of one multiplexer in the previous stage and the first port of one multiplexer in the previous N stages, where N is an integer greater than 1. The multiplexer can be any of the aforementioned multiplexers. This communication device is suitable for scenarios involving the multiplexing of dense narrowband beams, which correspond to different optical bands and can be provided by lasers or amplifiers.

[0221] Figure 27 This is a schematic diagram of the structure of an optical communication device provided in an embodiment of this application. Figure 27 As shown, the communication device includes three multiplexers 2, which are divided into two stages. The first stage includes two multiplexers 2, and the second port of each multiplexer 2 is connected to a laser. The two second ports of the multiplexers 2 in the second stage are respectively connected to the first ports of the two multiplexers 2 in the first stage.

[0222] For example, each laser has a wavelength coverage of 12nm, and the four lasers together cover 48nm. For instance, laser 1 has a wavelength range of 1524nm–1536nm, laser 2 has a wavelength range of 1536nm–1548nm, laser 3 has a wavelength range of 1548nm–1560nm, and laser 4 has a wavelength range of 1560nm–1572nm. If edge-type filtering devices are used as multiplexers, each multiplexer introduces a loss of 3nm, resulting in a final bandwidth loss of 9nm. However, using the multiplexer provided in this embodiment, each multiplexer introduces a loss of no more than 1nm, resulting in a final bandwidth loss of no more than 3nm, significantly improving the optical band utilization of the optical communication system.

[0223] It should be noted that, Figure 27 The laser in the optical communication device can also be replaced with other optical communication devices, such as optical amplifiers.

[0224] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. “A and / or B” indicates the presence of three possibilities: A, B, and A and B.

[0225] The above is merely one embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A splitter, characterized by include: First filter element (10), second filter element (20) and multiplexing assembly (30); The first filtering device (10) is used to divide the input beam (L0) into a first beam (L1) and a second beam (L2), wherein the first beam (L1) is light of a first wavelength band, and the second beam (L2) includes light of a second wavelength band and light of a third wavelength band, and the first wavelength band is located between the second wavelength band and the third wavelength band; The second filtering device (20) is used to divide the second beam (L2) into a first sub-beam (L21) and a second sub-beam (L22), wherein the first sub-beam (L21) is light of the second wavelength band and the second sub-beam (L22) is light of the third wavelength band; The beam combiner (30) is used to combine the first beam (L1) and the first sub-beam (L21) into a first mixed beam (L1'), or the beam combiner (30) is used to combine the first beam (L1) and the second sub-beam (L22) into a second mixed beam (L2'). Wherein, the width of the first transition wavelength range of the first filter device (10) is smaller than the width of the second transition wavelength range of the second filter device (20), and the first band and the second transition wavelength range at least partially overlap.

2. The splitter of claim 1, wherein The first band is a portion of the second transition wavelength range, and the sum of the width of the first band and the width of the first transition wavelength range is equal to the width of the second transition wavelength range; or, The first waveband completely overlaps with the second transition wavelength range; or... The first band includes the second transition wavelength range.

3. The splitter of claim 1, wherein The first filter device (10) is a bandpass filter device. The bandpass filter device is used to transmit light of the first band to obtain the first beam (L1), and to reflect light of the second band and the third band to obtain the second beam (L2).

4. The splitter of claim 1, wherein The second filter device (20) is an edge filter device, which is used to reflect the light of the second band to obtain the first sub-beam (L21) and transmit the light of the third band to obtain the second sub-beam (L22).

5. The splitter of claim 1, wherein, The wave combiner assembly (30) includes a reflector (31); The reflector (31) is used to reflect the first sub-beam (L21) to the first filter (10). The first filter device (10) is also used to reflect the first sub-beam (L21) from the reflector (31) to combine the first sub-beam (L21) with the first beam (L1) into the first mixed beam (L1').

6. The wave divider according to claim 1, characterized in that The wave combiner assembly (30) includes a reflector (31); The reflector (31) is used to reflect the first beam (L1) to the first filter (10). The first filter device (10) is also used to transmit the first beam (L1) from the reflector (31) and reflect the first sub-beam (L21) from the second filter device (20) to combine the first sub-beam (L21) with the first beam (L1) into the first mixed beam (L1').

7. The splitter of claim 6, wherein, The reflective device (31) and the first filter device (10) are configured such that the absolute value of the difference between any two of the first included angle, the second included angle and the third included angle is not greater than 3°; Wherein, the first included angle is the included angle between the first propagation path and the second propagation path, the first propagation path is the path of the input beam (L0) incident on the first filter device (10), and the second propagation path is the path of the second beam (L2) from the first filter device (10) to the second filter device (20); The second included angle is the angle between the second propagation path and the third propagation path, and the third propagation path is the path of the first sub-beam (L21) from the second filter device (20) to the first filter device (10); The third included angle is the angle between the third propagation path and the fourth propagation path, and the fourth propagation path is the path of the second sub-beam (L22) after being reflected by the first filter device (10).

8. The diplexer of claim 1, wherein, The beam combiner (30) includes a reflector (31) and a third filter (32), the reflector (31) being used to reflect the first sub-beam (L21) from the second filter (20) to the third filter (32). The third filter (32) is used to transmit the first beam (L1) from the first filter (10) and reflect the first sub-beam (L21) from the reflector (31) to combine the first beam (L1) and the first sub-beam (L21) into the first mixed beam (L1').

9. The splitter of claim 1, wherein, The beam combining assembly includes a reflector (31) and a fourth filter (33), wherein the reflector (31) is used to reflect the first beam (L1) from the first filter (10) to the fourth filter (33). The fourth filter (33) is used to transmit the first beam (L1) from the reflector (31) and reflect the first sub-beam (L21) from the second filter (20) to combine the first beam (L1) and the first sub-beam (L21) into the first mixed beam (L1').

10. The diplexer of claim 9, wherein, The propagation paths of the first beam (L1) from the first filter (10) to the reflector (31), the propagation paths of the first beam (L1) from the reflector (31) to the fourth filter (33), the propagation paths of the first sub-beam (L21) from the first filter (10) to the second filter (20), and the propagation paths of the first sub-beam (L21) from the second filter (20) to the fourth filter (33) are arranged in a parallelogram.

11. The diplexer of claim 9, wherein, The splitter further includes at least one intermediate filter element (41, 42, 43), which is used for at least one of the following: guiding the second beam (L2) from the first filter element (10) to the second filter element (20), guiding the first sub-beam (L21) from the second filter element (20) to the fourth filter element (33), and outputting the second sub-beam (L22) from the second filter element (20).

12. The splitter of any one of claims 1 to 11, wherein, The demultiplexer further includes: a fifth filter element (50) and a sixth filter element (60); The fifth filtering device (50) is used to divide the first mixed beam (L1') into a third beam (L3) and a fourth beam (L4), wherein the third beam (L3) is light of a first sub-band, and the fourth beam (L4) includes light of a second sub-band and light of a third sub-band, wherein the first sub-band is located between the second sub-band and the third sub-band; The sixth filtering device (60) is used to divide the fourth beam (L4) into a third sub-beam (L41) and a fourth sub-beam (L42), wherein the third sub-beam (L41) is light of the second sub-band and the fourth sub-beam (L42) is light of the third sub-band. The width of the third transition wavelength range of the fifth filter device (60) is smaller than the width of the fourth transition wavelength range of the sixth filter device (60), and the first sub-band at least partially overlaps with the fourth transition wavelength range.

13. The splitter of any of claims 5 to 11, wherein, The reflective device (31) is a reflective prism, or the reflective device (31) is a single reflector or a combination of at least two reflectors.

14. A multiplexer, comprising: include: First filtering device (10), first filtering device (20) and wavelength division component (30); The first filtering device (20) is used to combine the first sub-beam (L21) and the second sub-beam (L22) into a second beam (L2), wherein the first sub-beam (L21) is light in the second band and the second sub-beam (L22) is light in the third band; The first filtering device (10) is used to combine the first beam (L1) and the second beam (L2) into an output beam, wherein the first beam (L1) is light of a first band, and the first band is located between the second band and the third band; The wavelength division component (30) is used to receive the first mixed beam (L1') and to divide the first mixed beam (L1') into the first beam (L1) and the first sub-beam (L21). Wherein, the width of the first transition wavelength range of the first filter device (10) is smaller than the width of the second transition wavelength range of the first filter device (20), and the first band and the second transition wavelength range at least partially overlap.

15. The multiplexer of claim 14, wherein, The first band is a portion of the second transition wavelength range, and the sum of the width of the first band and the width of the first transition wavelength range is equal to the width of the second transition wavelength range; or, The first waveband completely overlaps with the second transition wavelength range; or... The first band includes the second transition wavelength range.

16. The multiplexer of claim 14, wherein, The first filter device (10) is a bandpass filter device, which is used to transmit the first beam (L1) and reflect the second beam (L2) to combine the first beam (L1) and the second beam (L2) into the output beam.

17. The multiplexer of claim 14, wherein, The first filter device (20) is an edge filter device, which is used to transmit the second sub-beam (L22) and reflect the first sub-beam (L21) to combine the first sub-beam (L21) and the second sub-beam (L22) into the second beam (L2).

18. The multiplexer of claim 14, wherein, The wavelength division component (30) includes a reflector (31); The first filter device (10) is also used to split the first mixed beam (L1') into the first beam (L1) and the first sub-beam (L21), and to reflect the first sub-beam (L21) to the reflector (31). The reflector (31) is used to reflect the first sub-beam (L21) to the first filter (20).

19. The multiplexer of claim 14, wherein, The wavelength division component (30) includes a reflector (31); The first filter device (10) is also used to split the first mixed beam (L1') into the first beam (L1) and the first sub-beam (L21), and to transmit the first beam (L1) to the reflector (31). The reflector (31) is used to reflect the first beam (L1) from the first filter (10) back to the first filter (10). The first filter device (10) is also used to transmit the first beam (L1) from the reflective device (31).

20. The multiplexer of claim 19, wherein, The reflective device (31) and the first filter device (10) are configured such that the absolute value of the difference between any two of the first included angle, the second included angle and the third included angle is not greater than 3°; Wherein, the first included angle is the included angle between the first propagation path and the second propagation path, the first propagation path is the path through which the output beam exits from the first filter device (10), and the second propagation path is the path through which the second beam (L2) travels from the first filter device (20) to the first filter device (10); The second included angle is the angle between the second propagation path and the third propagation path, and the third propagation path is the path of the first sub-beam (L21) from the first filter device (10) to the first filter device (20); The third included angle is the angle between the third propagation path and the fourth propagation path, and the fourth propagation path is the path through which the first mixed beam (L1') is incident on the first filter device (10).

21. The multiplexer of claim 14, wherein, The wavelength division component (30) includes a reflector (31) and a third filter (32). The third filter (32) is used to split the first mixed beam (L1') into the first beam (L1) and the first sub-beam (L21), guide the first beam (L1) to the first filter (10), and guide the first sub-beam (L21) to the reflector (31). The reflector (31) is used to reflect the first sub-beam (L21) from the third filter (32) back to the first filter (20).

22. The multiplexer of claim 14, wherein, The wavelength division component (30) includes a reflector (31) and a fourth filter (33). The fourth filter (33) is used to split the first mixed beam (L1') into the first beam (L1) and the first sub-beam (L21), guide the first beam (L1) to the reflector (31), and guide the first sub-beam (L21) to the first filter (20). The reflector (31) is used to reflect the first beam (L1) from the fourth filter (33) back to the first filter (10).

23. The multiplexer of claim 22, wherein, The propagation paths of the first beam (L1) from the fourth filter (33) to the reflector (31), the propagation paths of the first beam (L1) from the reflector (31) to the first filter (10), the propagation paths of the first sub-beam (L21) from the fourth filter (33) to the first filter (20), and the propagation paths of the first sub-beam (L21) from the first filter (20) to the first filter (10) are arranged in a parallelogram.

24. The multiplexer of claim 23, wherein, The combiner further includes at least one intermediate filter (40) for performing at least one of the following: directing the first sub-beam (L21) from the fourth filter (33) to the first filter (20), directing the first sub-beam (L21) from the first filter (20) to the first filter (10), and directing the second sub-beam (L22) to the first filter (20).

25. The multiplexer of any of claims 14 to 24, wherein, The combiner also includes a fifth filter element (50) and a sixth filter element (60). The sixth filtering device (60) is used to combine the third sub-beam (L41) and the fourth sub-beam (L42) into a fourth beam (L4), wherein the third sub-beam (L41) is light of the second sub-band and the fourth sub-beam (L42) is light of the third sub-band. The fifth filtering device (50) is used to combine the third beam (L3) and the fourth beam (L4) into the first mixed beam (L1'), wherein the third beam (L3) is light of the first sub-band; The width of the third transition wavelength range of the fifth filter device (50) is smaller than the width of the fourth transition wavelength range of the sixth filter device (60), and the first sub-band at least partially overlaps with the fourth transition wavelength range.

26. The multiplexer of any of claims 18 to 24, wherein, The reflective device (31) is a reflective prism, or the reflective device (31) is a single reflector or a combination of at least two reflectors.

27. An optical communication device, comprising: The device includes a beam splitter unit and a beam combiner unit. The beam splitter unit includes at least one beam splitter as described in any one of claims 1 to 13, and the beam combiner unit includes at least one beam combiner as described in any one of claims 14 to 26. The beam combiner unit is used to combine multiple beams output by the beam splitter unit.

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