CN112152750B

CN112152750B - Wavelength selective switch and related device

Info

Publication number: CN112152750B
Application number: CN201910581369.9A
Authority: CN
Inventors: 邹冰; 赵晗; 闫云飞
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-06-29
Filing date: 2019-06-29
Publication date: 2021-12-31
Anticipated expiration: 2039-06-29
Also published as: CN112152750A; WO2021000616A1

Abstract

The embodiment of the application discloses a wavelength selective switch, includes: the input fiber collimation array comprises a plurality of input ports; the relay lens is positioned between the first switching engine and the second switching engine; the first lens group comprises A lenses, the second lens group comprises B lenses, A and B are natural numbers which are larger than or equal to 2, the first lens group is connected with the first switching engine and the relay lens, the second lens group is connected with the relay lens and the second switching engine, and the first lens group and the second lens group both comprise lenses with curvatures in dispersion directions; the output fiber collimating array includes a plurality of output ports. By providing two or more lens groups between the switching engines. The filtering cost of the wavelength selective switch is reduced, and the filtering bandwidth of the wavelength selective switch is improved.

Description

Wavelength selective switch and related device

Technical Field

The present application relates to the field of optical communication technologies, and in particular, to a wavelength selective switch and a related device.

Background

With the rapid growth of video and cloud services, operators pay special attention to the flexibility of optical network construction and the reduction of the construction, operation and maintenance costs of optical networks. Network nodes need more and more direction dimensions (or transmission paths) of cross connection, and an operator can remotely and automatically switch the dimensions by using a reconfigurable optical add-drop multiplexer (ROADM) to replace the connection of optical fibers by manually dropping the sites in the prior art, so that the requirement of network dynamic connection is met. In order to meet the requirements of high efficiency and flexibility of high-speed optical communication networks, ROADMs serving as network cross-connect cores need to be continuously developed.

In the current ROADM node, the use of discretization devices is a common implementation. When network traffic increases, the capacity of traffic switching in a node needs to be increased by increasing the number of 1 × N Wavelength Selective Switches (WSS). However, this requires a large increase in the number of module slots in the existing device in order to access a plurality of 1 × N wavelength selective switches, which increases the cost of the device and also increases the cost sharply with the increase in traffic.

Therefore, now, an N × M wavelength selective switch and an N × N wavelength selective switch are proposed, which can improve the service switching capability in the node and save the number of wavelength selective switches, where N and M are different positive integers greater than 1. In both the nxm wavelength selective switch and the nxn wavelength selective switch, two or more stages of switching engines are required to focus the corresponding optical signals to the corresponding spatial locations. However, the filtering effect of the switching engine degrades the signal quality when the optical signal passes through each stage of switching engine, and the filtering effect is particularly significant under the condition of cascade connection of multiple stages of switching engines, which can seriously degrade the channel quality.

Disclosure of Invention

The embodiment of the application provides a wavelength selective switch and a related device, wherein two or more lens groups are arranged between switching engines, and the lens groups comprise X lenses with curvatures in dispersion directions, wherein X is a natural number which is greater than or equal to 2. The filtering cost of the wavelength selective switch is reduced, the filtering bandwidth of the wavelength selective switch is improved, and the channel quality is improved.

The embodiment of the application provides the following technical scheme:

in a first aspect, an embodiment of the present application provides a wavelength selective switch, including: the optical fiber switching system comprises an input optical fiber collimation array, a first switching engine, a relay lens, a first lens group, a second switching engine and an output optical fiber collimation array; the input optical fiber collimation array comprises N input ports, wherein N is a natural number greater than 1; the first switching engine is connected with the input optical fiber collimation array; the relay lens is connected with the first switching engine and the second switching engine, the relay lens is positioned between the first switching engine and the second switching engine, and the relay lens is a lens in the direction of a switching optical path; the first lens group comprises A lenses, the second lens group comprises B lenses, A is a natural number which is greater than or equal to 2, B is a natural number which is greater than or equal to 2, the first lens group is connected with the first switching engine and the relay lens, the second lens group is connected with the relay lens and the second switching engine, and the first lens group and the second lens group at least comprise lenses with curvatures in the dispersion direction; the output optical fiber collimation array comprises M output ports, M is a natural number larger than 1, and the output optical fiber collimation array is connected with the second switching engine.

In the embodiment of the present application, a first lens group and a second lens group are disposed between two stages of switching engines in a wavelength selective switch, where the first lens group and the second lens group at least include lenses with curvatures in dispersion directions, the first lens group includes a number a of lenses with curvatures in dispersion directions, and the second lens group includes a number B of lenses with curvatures in dispersion directions, where a is a natural number greater than or equal to 2, and B is a natural number greater than or equal to 2. The filtering cost of the wavelength selective switch is reduced, the filtering bandwidth of the wavelength selective switch is improved, and the channel quality is improved.

In one possible implementation of the first aspect, a sum of distances between lenses in the first lens group is equal to a sum of focal lengths of lenses in the first lens group; the distance between the lens closest to the relay lens in the first lens group and the relay lens is equal to the focal length of the lens; the sum of the distances between the lenses in the second lens group is equal to the sum of the focal lengths of the lenses in the second lens group; the distance between the lens closest to the relay lens in the second lens group and the relay lens is equal to the focal length of the lens, and the sum of A and B is an even number.

In the embodiment of the present application, the first lens group and the second lens group between the two stages of switching engines in the wavelength selective switch are arranged in the order of the 4f optical system, a + B lenses are shared in the dispersion direction to form a (2(a + B)) f optical system, and when an optical signal passes through the (2(a + B)) f optical system, a light spot distribution region is consistent with a region where the optical signal is projected on the first switching engine when the optical signal reaches the second switching engine, and the light spot distribution is within the switching region. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced.

In one possible implementation of the first aspect, a sum of focal lengths of the lenses in the first lens group is equal to a focal length of the relay lens; the sum of the focal lengths of the lenses in the second lens group is equal to the focal length of the relay lens.

In the embodiment of the application, since the sum of the focal lengths of the lenses in the first lens group is equal to the focal length of the relay lens, and the sum of the focal lengths of the lenses in the second lens group is equal to the focal length of the relay lens, the size of the light beam output by the first interaction engine is consistent with the size of the light beam input to the second exchange engine. The first swap engine, the first lens group, the relay lens, the second lens group, and the second swap engine together form a 2f optical system centered on the relay lens.

In one possible implementation of the first aspect, the wavelength selective switch further comprises: a first dispersion element and a second dispersion element;

the first dispersion element is connected with the input fiber collimation array and the first switching engine, and the first dispersion element is positioned between the input fiber collimation array and the first switching engine; the second dispersive element is connected with the second switching engine and the output optical fiber collimation array, and the second dispersive element is positioned between the second switching engine and the output optical fiber collimation array.

In one possible implementation of the first aspect, the wavelength selective switch further comprises: the third lens group comprises C lenses, the fourth lens comprises D lenses, C is a natural number which is greater than or equal to 2, and D is a natural number which is greater than or equal to 2; the third lens group is connected with the input optical fiber collimation array and the first dispersion element, and is connected with the first dispersion element and the first switching engine, and the first dispersion element is positioned between lenses of the third lens group; the fourth lens group is connected with the second exchange engine and the second dispersion element, the second dispersion element is connected with the output optical fiber collimation array, and the second dispersion element is located between lenses of the fourth lens group. The sum of the distances between the lenses in the third lens group is equal to the sum of the focal lengths of the lenses in the third lens group; the distance between the lens in the third lens group closest to the first exchange engine and the first exchange engine is equal to the focal length of the lens; the sum of the distances between the lenses in the fourth lens group is equal to the sum of the focal lengths of the lenses in the fourth lens group; the lens in the fourth lens group closest to the second interchange engine is away from the second interchange engine by a distance equal to the focal length of the lens, and the sum of C and D is an even number.

In the embodiment of the present application, since (a + B) lenses are shared in the dispersion direction between the two stages of switching engines in the wavelength selective switch, a (2(a + B)) f optical system is formed, and when an optical signal passes through the (2(a + B)) f optical system and reaches the second switching engine, the light spot distribution area is consistent with the area where the optical signal is projected on the first switching engine, and the light spot distribution is within the switching area. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. The first dispersion element opens the dispersion of the light beams from the input fiber collimation array, projects the light beams on the first switching engine according to different wavelengths, and combines the different light beams in the dispersion direction into one light beam after the light beams with different wavelengths pass through the second dispersion element. The first dispersion element and the second dispersion element are arranged, so that the deflection of the light beams with different wavelengths is realized. By arranging the third lens group and the fourth lens group, the compensation of chromatic dispersion and chromatic aberration is provided for optical signals in the wavelength switch, and the optical performance of the wavelength switch is improved.

In one possible implementation of the first aspect, the wavelength selective switch further comprises: a third dispersion element and a fourth dispersion element; the third dispersive element is positioned between the first exchange engine and the relay lens; the fourth dispersive element is located between the relay lens and the second switching engine.

In the embodiment of the present application, by providing the third dispersive element and the fourth dispersive element, the extra off-axis aberration generated during the transmission of the light beam is effectively reduced, and the optical performance of the wavelength selective switch is improved.

In one possible implementation of the first aspect, the wavelength selective switch further comprises: the fifth lens group comprises E lenses, E is a natural number which is greater than or equal to 2, and the sum of the distances between the lenses in the fifth lens group is equal to the sum of the focal lengths of the lenses in the fifth lens group; the distance between the lens in the fifth lens group closest to the first exchanging engine and the first exchanging engine is equal to the focal length of the lens; the sixth lens comprises F lenses, wherein F is a natural number which is greater than or equal to 2, and the sum of the distances between the lenses in the sixth lens group is equal to the sum of the focal lengths of the lenses in the sixth lens group; the distance between the lens in the sixth lens group closest to the second interchange engine and the second interchange engine is equal to the focal length of the lens; the fifth lens group is connected with the first switching engine and the third dispersing element, and is connected with the third dispersing element and the first lens group, and the third dispersing element is positioned between lenses of the fifth lens group; the sixth lens group is connected with the second lens group and the fourth dispersion element, the fourth dispersion element is connected with the second switching engine, the fourth dispersion element is positioned between the lenses of the sixth lens group, and the sum of E and F is an even number.

In the embodiment of the present application, the wavelength selective switch includes a plurality of lens sets and a chromatic dispersion element, the fifth lens set and the sixth lens set are used for compensating chromatic dispersion and chromatic aberration of an optical signal, and the third chromatic dispersion element and the fourth chromatic dispersion element are used for reducing extra off-axis aberration generated during transmission of a light beam, so as to improve the optical performance of the wavelength switch.

In one possible implementation of the first aspect, the wavelength selective switch further comprises: a seventh lens group and an eighth lens group; the seventh lens group is connected with the first switching engine and the first lens group; the eighth lens group is connected with the second lens group and the second switching engine; the seventh lens group includes G lenses, and the eighth lens group includes H lenses, G being a natural number greater than or equal to 2, and H being a natural number greater than or equal to 2. The sum of distances between lenses in the seventh lens group is equal to the sum of focal lengths of the lenses in the seventh lens group; the distance between the lens closest to the first exchange engine in the seventh lens group and the first exchange engine is equal to the focal length of the lens; the sum of distances between lenses in the eighth lens group is equal to the sum of focal lengths of lenses in the eighth lens group; and the lens in the eighth lens group closest to the second interchange engine is away from the second interchange engine by a distance equal to the focal length of the lens, and the sum of G and H is an even number.

In the embodiment of the present application, when the seventh lens group and the eighth lens group include lenses having curvature in the dispersion direction, between the two stages of switching engines in the wavelength selective switch, there are (a + B + G + H) lenses in total in the dispersion direction, and a (2(a + B + G + H)) f optical system is formed, and after an optical signal passes through the (2(a + B + G + H)) f optical system, a light spot distribution region when the optical signal reaches the second switching engine coincides with a region where the optical signal is projected onto the first switching engine, and the light spot distribution is within the switching region. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. By arranging the seventh lens group and the eighth lens group, chromatic dispersion and chromatic aberration compensation is provided for optical signals in the wavelength switch, and the optical performance of the wavelength switch is improved.

In a second aspect, embodiments of the present application provide an optical splitter, which includes the wavelength selective switch of the first aspect.

In a third aspect, an embodiment of the present application provides a reconfigurable optical add/drop multiplexer, where the reconfigurable optical add/drop multiplexer includes the wavelength selective switch of the first aspect.

According to the technical scheme, the embodiment of the application has the following advantages:

two or more lens groups are arranged between the switching engines, and the lens groups comprise a plurality of lenses with curvatures in dispersion directions, so that the compensation of chromatic dispersion chromatic aberration is provided for optical signals, the filtering cost of the wavelength selective switch is reduced, the filtering bandwidth of the wavelength selective switch is improved, the optical performance of the wavelength switching switch is improved, and the channel quality is improved.

Drawings

Fig. 1 is a schematic diagram of a reconfigurable optical add/drop multiplexer according to an embodiment of the present disclosure;

FIG. 2a is a schematic diagram of a spot distribution on a switching engine according to an embodiment of the present application;

FIG. 2b is a schematic diagram of another spot distribution on the switching engine in the embodiment of the present application;

FIG. 2c is a schematic diagram of a filtered spectrum according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a light spot of a wavelength selective switch according to an embodiment of the present application;

fig. 4a is a schematic structural diagram of a wavelength selective switch according to an embodiment of the present application;

fig. 4b is a schematic structural diagram of a wavelength selective switch according to an embodiment of the present application;

FIG. 5 is a schematic diagram of an optical path along the dispersion direction of a wavelength selective switch according to an embodiment of the present application;

fig. 6 is a schematic optical path diagram illustrating the switching of the optical path direction of the wavelength selective switch according to the embodiment of the present application;

FIG. 7 is a schematic view of a light spot in an embodiment of the present application;

FIG. 8 is a schematic diagram of a simulated waveform of a filter bandwidth in an embodiment of the present application;

fig. 9 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application;

fig. 12 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application;

fig. 14 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application.

Detailed Description

In order to make the technical field of the present application better understand, embodiments of the present application will be described below with reference to the accompanying drawings.

The application provides a Wavelength Selective Switch (WSS) and relevant device, through set up two or more than battery of lens between the switching engine, there is the lens of camber in the battery of lens including A + B dispersion direction, has reduced wavelength selective switch's filtering cost, has promoted wavelength selective switch's filtering bandwidth, promotes channel quality. The term "connection" in the embodiments of the present application refers to a connection on an optical path, and those skilled in the art will understand that specific optical devices may not necessarily have a physical connection with substantial contact, but the spatial positions of the optical devices and their own device characteristics make them form a connection on an optical path.

Referring to fig. 1, fig. 1 is a schematic diagram of a reconfigurable optical add/drop multiplexer according to an embodiment of the present disclosure. The reconfigurable optical add-drop multiplexer (ROADM) in fig. 1 is a reconfigurable optical add-drop multiplexer (ROADM) for connecting multi-dimensional light to multi-dimensional light, and the reconfigurable optical add-drop multiplexer is based on NxM or NxN wavelength selective switches, where N and M are positive integers greater than 1 and different from each other. For the NxM wavelength selective switch or the NxN wavelength selective switch, two or more stages of switching engines are required to be used for implementation, for convenience of understanding, the wavelength selective switch of the two stages of switching engines is taken as an example for description in the embodiment of the present application, and it should be noted that the wavelength selective switch provided in the embodiment of the present application may be applied to a wavelength selective switch of not only a two-stage switching engine but also a three-stage switching engine or a wavelength selective switch of more than three stages of switching engines, which is not limited herein. The filtering effect of the switching engine in the wavelength selective switch is described next.

Referring to fig. 2a, fig. 2a is a schematic diagram illustrating a distribution of light spots on a switching engine in an embodiment of the present application, after receiving an optical signal in a wavelength selective switch, the optical signal is projected on the switching engine as three light spots, which are: λ 1, λ 2, and λ 3. The distribution of the three light spots is shown in fig. 2a, wherein the abscissa of fig. 2a is the dispersion direction, and the ordinate is the exchange optical path direction. The switching engine processes the optical signals corresponding to the three light spots, specifically please refer to fig. 2b, and fig. 2b is another schematic diagram of the distribution of the light spots on the switching engine in the embodiment of the present application. In fig. 2b, the horizontal line coverage area is an area where wavelength switching (lambda switching) occurs in the optical signal in the switching engine, and only the optical signal projected in the horizontal line coverage area can be deflected in the wavelength direction, and taking fig. 2b as an example, the right half of λ 1, the entire portion of λ 2, and the left half of λ 3 can be wavelength-switched. Since λ 1 and λ 3 are partially cut during wavelength switching, the optical signal energy corresponding to λ 1 and λ 3 is reduced after being processed by the switching engine. Specifically, as shown in fig. 2c, fig. 2c is a schematic diagram of a filtered spectrum according to an embodiment of the present application. Since λ 1 and λ 3 are partially cut, part of energy is lost after the optical signal passes through the switching engine, and the effect of the switching engine on the partial cutting of the optical signal is called filtering effect. The filter spectrum generated for the optical signals (λ 1, λ 2, and λ 3) in the wavelength switching region of the switching engine in fig. 2b is shown in fig. 2c, where the abscissa is the wavelength and the ordinate is the transmittance, and it can be seen that at the positions of the wavelengths λ 1 and λ 3, due to the decrease of the transmittance, the slope of the edge of the filter spectrum is small, deteriorating the quality of the optical signals. At the positions of the wavelengths λ 1 and λ 3, the slope of the edges of the filtered spectrum is small, and the filtering effect is also called filtering cost.

Such a filtering effect occurs every time when the optical signal passes through the first-stage switching engine, and the embodiment of the present application provides a wavelength selective switch, and after the optical signal passes through the first switching engine, the light spot projected on the edge of the wavelength switching area is not partially cut, so that the transmission efficiency of the optical signal after the first switching engine is ensured, the filtering cost of the wavelength selective switch is reduced, the filtering bandwidth of the wavelength selective switch is improved, and the channel quality is improved. Taking a two-stage switching engine as an example for explanation, please refer to fig. 3 specifically, and fig. 3 is a schematic diagram of a light spot of a wavelength selective switch in the embodiment of the present application. Fig. 3 shows the spot λ 1 as exemplified in fig. 2 a-2 c, after passing through the first switching engine, since only the right half is wavelength switched. The wavelength-switched spot is projected onto the wavelength-switched region (the cross-line coverage region) of the second switching engine, so that the spot is not partially cut, the spot is fully projected onto the wavelength-switched region of the second switching engine, all the energy of the spot is exchanged, no additional energy loss is generated, and no additional filtering cost is generated in the second switching engine.

Referring to fig. 4a, fig. 4a is a schematic structural diagram of a wavelength selective switch according to an embodiment of the present application. The wavelength selective switch provided by the embodiment of the application comprises: the optical fiber switch comprises an input Fiber Collimating Array (FCA), a first switching engine, a first lens group, a relay lens, a second lens group, a second switching engine and an output fiber collimating array.

In this application embodiment, optical signal gets into wavelength selection switch through input fiber collimation array, and input fiber collimation array carries out collimation processing to optical signal, and input collimator array is listed as one row in the vertical direction, can also include in the input fiber collimation array: an input port, an input fiber array, and an input collimator array. The input port receives an external input optical signal; an input side fiber array and an input collimator array; the input collimator array is aligned in a vertical direction, and makes the optical signal from the input port be input to the subsequent optical element in parallel. And the output optical fiber collimation arrays correspond to the input optical fiber collimation array, are arranged in a row in the vertical direction and are used for outputting optical signals from the second switching engine, and each output optical fiber collimation array comprises an output collimator array and an output optical fiber array, wherein the optical signals are transmitted to an output port from the output collimator array and the output optical fiber array.

After the input fiber alignment array, a first switching engine is connected, and the switching engine in the embodiment of the present application includes at least two stages of switching engines: it should be noted that, when the switching engine in the wavelength selective switch is a switching engine with three or more stages, the first switching engine and the second switching engine are similar to the case where the wavelength selective switch is a switching engine with two stages, and are not described herein again. The switching engine is used for adjusting the deflection angle of incident light and focusing the corresponding optical signal to the corresponding spatial position.

After the first switching engine, a first lens group is connected, the first lens group comprises A lenses, A is a natural number which is greater than or equal to 2, and the first lens group at least comprises a lens with curvature in the dispersion direction.

After the first lens group, a relay lens is attached. The relay lens is a cylindrical lens in the exchange optical path direction, and may be a single cylindrical lens or a combination of a plurality of cylindrical lenses, and has a curvature only on the exchange optical path.

After the relay lens, a second lens group is connected. The second lens group comprises B lenses, B is a natural number which is greater than or equal to 2, the first lens group is connected with the first exchange engine and the relay lens, the second lens group is connected with the relay lens and the second exchange engine, and the first lens group and the second lens group at least comprise lenses with curvatures in dispersion directions. The first lens group at least comprises a lens with curvature in the dispersion direction, the second lens group at least comprises a lens with curvature in the dispersion direction, and the lens of the first lens group and the lens of the second lens group can compensate dispersion and chromatic aberration of optical signals and effectively improve optical performance.

After the second lens group, an output fiber collimating array is attached. The output fiber collimation array comprises a plurality of output ports, and the optical signals output the wavelength selection switch through the output ports in the output fiber collimation array.

In the embodiment of the application, two or more lens groups are arranged between the switching engines, and the lens groups comprise a plurality of lenses with curvatures in dispersion directions, so that the compensation of chromatic dispersion aberration is provided for optical signals, the filtering cost of the wavelength selective switch is reduced, the filtering bandwidth of the wavelength selective switch is improved, the optical performance of the wavelength switching switch is improved, and the channel quality is improved.

The wavelength selective switch provided in the embodiment of the present application may further include more optical elements, and specifically, please refer to fig. 4b, where fig. 4b is a schematic structural diagram of the wavelength selective switch provided in the embodiment of the present application. The wavelength selective switch provided by the embodiment of the application comprises: the optical fiber collimating module comprises an input optical Fiber Collimating Array (FCA), a third lens group, a first dispersive element, a first switching engine, a fifth lens group, a third dispersive element, a fifth lens group, a first lens group, a relay lens, a second lens group, a sixth lens group, a fourth dispersive element, a sixth lens group, a second switching engine, a fourth lens group, a second dispersive element, a fourth lens group and an output optical fiber collimating array.

These optical elements can be classified into the following six categories in general: the input fiber collimation array, the lens group, the dispersion element, the switching engine, the relay lens and the output fiber collimation array, the function of each optical element is described firstly:

specifically, the input fiber collimation array is arranged in a row in the vertical direction, and the input fiber collimation array may further include: the optical fiber array comprises an input port, an input optical fiber array and an input collimator array, wherein the input port receives an external input optical signal; an input side fiber array and an input collimator array; the input collimator array is aligned in a vertical direction, and makes the optical signal from the input port be input to the subsequent optical element in parallel. The input optical fiber collimation array comprises N input ports, wherein N is a natural number larger than 1. And the output optical fiber collimation array comprises an output collimator array and an output optical fiber array, wherein the output optical fiber collimation array corresponds to the input optical fiber collimation array, the M is a natural number larger than 1, the output optical fiber collimation array is arranged in a row in the vertical direction and is used for outputting optical signals from the second switching engine, and the output optical fiber collimation array comprises the output collimator array and the output optical fiber array, wherein the optical signals are transmitted to the output port from the output collimator array and the output optical fiber array.

The switching engine, which may be a micro-electro mechanical system (MEMS) or a Liquid Crystal On Silicon (LCOS), may configure parameters of corresponding MEMS mirrors or LCOS pixels according to the wavelength routing configuration information to adjust a deflection angle from incident light, and focus corresponding optical signals onto corresponding spatial positions. In the MEMS, a light beam impinging on a micromirror may be deflected by a mechanical motion of the micromirror, so as to implement deflection of an optical path, thereby implementing dimension (or transmission path) switching of signal light; in the LCOS, a blazed grating can be formed by configuring the phases of the pixels to deflect the corresponding incident light.

The relay lens may be a single cylindrical lens or a combination of a plurality of cylindrical lenses, and the relay lens is a cylindrical lens in the exchange optical path direction, and has a curvature only on the exchange optical path. The relay lens is used for switching the optical signals input by the input optical fiber collimation array to the corresponding ports of the output optical fiber collimation array so as to realize that the optical signals are input to the N input ports and output from the M output ports. The sum of the focal lengths of the lenses in the first lens group is equal to the focal length of the relay lens; the sum of the focal lengths of the lenses in the second lens group is equal to the focal length of the relay lens.

The lens group in the embodiment of the present application includes a lens, the lens may be a cylindrical lens having a curvature in a dispersion direction, the cylindrical lens having a curvature in the dispersion direction is used for converging or diverging an optical signal in the dispersion direction, the lens may compensate dispersion and chromatic aberration of the optical signal, and effectively improve optical performance, and may also be a lens having a curvature in the dispersion direction and having a curvature on an exchange optical path at the same time, at this time, the lens group may converge both the optical signal in the dispersion direction and the optical signal in the optical path direction. The dispersive element includes one or more gratings, which may be reflective diffraction gratings or transmissive diffraction gratings, prisms, and a focusing lens, and is not limited herein.

The grating or prism in the dispersive element is used for separating different wavelengths, and the focusing lens is used for collimating the different wavelengths of light from the grating and converging the single wavelength of light from the grating. The lens group and the dispersion element are used for changing the beam size of the optical signal and changing the optical signal into polarized light in one polarization state.

In the embodiment of the application, the lens group comprises: a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, and a sixth lens group, wherein: each of the first lens group, the second lens group, the third lens group, the fourth lens group, the fifth lens group, and the sixth lens group includes at least two lenses.

The first lens group comprises A lenses, the second lens group comprises B lenses, A is a natural number which is greater than or equal to 2, B is a natural number which is greater than or equal to 2, and the sum of A and B is an even number. The sum of the distances between the lenses in the first lens group is equal to the sum of the focal lengths of the lenses in the first lens group; the distance between the lens closest to the relay lens in the first lens group and the relay lens is equal to the focal length of the lens; the sum of the distances between the lenses in the second lens group is equal to the sum of the focal lengths of the lenses in the second lens group; the distance between the lens closest to the relay lens in the second lens group and the relay lens is equal to the focal length of the lens. The sum of the focal lengths of the lenses in the first lens group is equal to the focal length of the relay lens; the sum of the focal lengths of the lenses in the second lens group is equal to the focal length of the relay lens.

The third lens group comprises C lenses, the fourth lens comprises D lenses, C is a natural number which is greater than or equal to 2, D is a natural number which is greater than or equal to 2, and the sum of C and D is an even number. The sum of the distances between the lenses in the third lens group is equal to the sum of the focal lengths of the lenses in the third lens group; the distance between the lens in the third lens group closest to the first exchange engine and the first exchange engine is equal to the focal length of the lens; the sum of the distances between the lenses in the fourth lens group is equal to the sum of the focal lengths of the lenses in the fourth lens group; and the distance between the lens in the fourth lens group closest to the second interchange engine and the second interchange engine is equal to the focal length of the lens.

The fifth lens group comprises E lenses, E is a natural number which is greater than or equal to 2, and the sum of the distances between the lenses in the fifth lens group is equal to the sum of the focal lengths of the lenses in the fifth lens group; the distance between the lens closest to the first exchange engine in the fifth lens group and the first exchange engine is equal to the focal length of the lens, the sixth lens comprises F lenses, F is a natural number greater than or equal to 2, and the sum of the distances between the lenses in the sixth lens group is equal to the sum of the focal lengths of the lenses in the sixth lens group; and the distance between the lens in the sixth lens group closest to the second exchange engine and the second exchange engine is equal to the focal length of the lens, and the sum of E and F is an even number.

It should be noted that, as those skilled in the art can understand, there are many devices that can implement the above functions, and the embodiment of the present application is given as an example only.

Next, a specific structure of the wavelength selective switch according to the embodiment of the present application is described with reference to fig. 5 and fig. 6, where fig. 5 is a schematic optical path diagram in a dispersion direction of the wavelength selective switch according to the embodiment of the present application, and fig. 6 is a schematic optical path diagram in a switching optical path direction of the wavelength selective switch according to the embodiment of the present application.

For convenience of understanding, the wavelength selective switch in fig. 5 and 6 is described by taking an example of a case where the lens groups are 2 lenses, the dispersive elements are 1 grating, and the two-stage switching engine, and it should be noted that the kind and number of the optical elements in the wavelength selective switch are not limited. It is understood that the case where the lens group in the wavelength selective switch is more than 2 lenses, and/or the dispersion element is 1 prism, and/or the switching engine has more than two stages, also falls within the scope of the present application. In this application, "X and/or Y" may be understood as: x, or Y, or X and Y.

In the wavelength selective switch shown in fig. 5 and 6, an optical signal is input from an input optical fiber collimation array, where the input optical fiber collimation array includes N input optical fibers and N collimating lenses, and is used to collimate and output an input optical signal with N dimensions, where N is a natural number greater than 1.

The third lens group includes a lens 1 and a lens 2, the lens 1 and the lens 2 may be lenses with the same or different focal lengths, and specifically may be a cylindrical lens with curvature in a dispersion direction, a distance between the lens 1 and the lens 2 is equal to the sum of the focal lengths of the lens 1 and the lens 2, a distance between the lens 1 and the input optical fiber collimation array is equal to the focal length of the lens 1, and a distance between the lens 2 and the first switching engine is equal to the focal length of the lens 2, that is, the lens 1 and the lens 2 constitute a 4f optical system in a wavelength direction. In the third lens group, there is a first dispersive element, which includes a grating 1, and the light beam enters the grating 1 through the lens 1, and after the grating 1 is dispersed and opened, the light beam is transmitted to different areas of the first switching engine through the lens 2 according to different wavelengths, and the distribution of the light spots projected on the first switching engine is as can be seen in fig. 2 a-2 b.

Behind the first switching engine, connected is a fifth lens group. The fifth lens group comprises a lens 3 and a lens 4, the lens 3 and the lens 4 can be lenses with the same or different focal lengths, the distance between the lens 3 and the lens 4 is equal to the sum of the focal lengths of the lens 3 and the lens 4, and the distance between the lens 3 and the first switching engine is equal to the focal length of the lens 3, namely the lens 3 and the lens 4 form a 4f optical system. In the fifth lens group there is a third dispersive element comprising a grating 2. The grating 2 is located between the lens 3 and the lens 4, and after the optical signal passes through the first switching engine, the light beams with different wavelengths pass through the grating 2, and the different light beams in the dispersion direction are combined into one light beam. By providing a third dispersive element: the grating 2 effectively reduces the extra off-axis aberration generated by the light beam when the light beam passes through the relay lens, and when the number of input ports is large (for example, N >5), the off-axis aberration is too large, so that the light beam generates displacement deviation on the second switching engine, and the whole filtering spectrum is affected. The position of the third dispersive element relative to the fifth lens group is determined by the optical performance parameters of the respective optical elements, and is not limited herein.

Behind the fifth lens group, connected is the first lens group. The first lens group comprises a lens 5 and a lens 6, the lens 5 and the lens 6 can be lenses with the same or different focal lengths, the distance between the lens 5 and the lens 6 is equal to the sum of the focal lengths of the lens 5 and the lens 6, the distance between the lens 6 and the relay lens is equal to the focal length of the lens 6, namely the lens 5 and the lens 6 form a 4f optical system, and the lenses in the first lens group can only be lenses with curvatures in the dispersion direction. The optical signal passes through the lens 5 and the lens 6 to reach a relay lens, which is a lens for exchanging the optical path direction.

After passing through the fifth lens group, the optical signal enters a relay lens, and the relay lens converts the switching angle introduced by the first switching engine into a deviation on the position of the light beam. The second lens group is connected behind the relay lens, the second lens group comprises a lens 7 and a lens 8, the lens 7 and the lens 8 can be lenses with the same or different focal lengths, the distance between the lens 7 and the lens 8 is equal to the sum of the focal lengths of the lens 7 and the lens 8, the distance between the lens 7 and the first switching engine is equal to the focal length of the lens 7, and the lens 7 and the lens 8 form a 4f optical system.

And the optical signal enters a sixth lens group after passing through the second lens group, and the sixth lens group is connected with the second lens group. The sixth lens group comprises a lens 9 and a lens 10, the lens 9 and the lens 10 can be lenses with the same or different focal lengths, the distance between the lens 9 and the lens 10 is equal to the sum of the focal lengths of the lens 9 and the lens 10, the distance between the lens 10 and the second switching engine is equal to the focal length of the lens 10, namely the lens 9 and the lens 10 form a 4f optical system, and the lenses in the second lens group can only be lenses with curvature in the dispersion direction. In the sixth lens group, there is a fourth dispersive element including a grating 3. The grating 3 is located between the lens 9 and the lens 10, and the optical performance of the grating 3 is consistent with that of the grating 2. The grating 3 is used to disperse the beam open. The position of the fourth dispersion element with respect to the sixth lens group is determined by the optical performance parameters of the respective optical elements, and is not limited herein.

The optical signal passes through the second lens group and then reaches the second switching engine. And the second-stage switching engine deflects the light beam by a corresponding angle again according to the angle of the light beam and the output port to ensure that the light beam can reach the expected output port. The spot distribution of the beam projected on the second switching engine is as can be seen in fig. 2 a-2 b.

After passing through the second switching engine, the optical signal reaches a fourth lens group, where the fourth lens group includes a lens 11 and a lens 12, the lens 11 and the lens 12 may be lenses with the same or different focal lengths, a distance between the lens 11 and the lens 12 is equal to a sum of focal lengths of the lens 11 and the lens 12, and a distance between the lens 11 and the second switching engine is equal to a focal length of the lens 1, that is, the lens 11 and the lens 12 constitute a 4f optical system. In the fourth lens group there is a second dispersive element comprising a grating 4. The grating 3 is located between the lens 11 and the lens 12, and the grating 4 has the same optical performance as the grating 1. The grating 3 is used to multiplex the dispersed and opened beams. The light beams after wave combination reach the output end, the output end comprises an output optical fiber collimation array, the output optical fiber collimation array comprises M input optical fibers and M collimation lenses and is used for outputting the light signals to M dimensions after being collimated, and M is a natural number larger than 1.

Referring to fig. 7, in the wavelength selective switch of fig. 5-6, a schematic diagram of cutting a light spot on a switching engine is shown, and fig. 7 is a schematic diagram of a light spot according to an embodiment of the present disclosure. In fig. 7, the semi-circle is an illustration of the light spot, and after passing through the first switching engine, the light spot becomes a semi-oval light spot, and the light spot is directed downward. After passing through an 8f optical system consisting of four lenses (lenses 3, 4, 5 and 6), the spot propagates to the position of the relay lens. After passing through a 4f optical system formed by the first two lenses (lens 3 and lens 4), the semi-elliptical light spot is turned over once, and after passing through a 4f optical system formed by the second two lenses (lens 5 and lens 6), the light spot is turned over once again. Similarly, after passing through an 8f optical system consisting of four lenses (lenses 7, 8, 9, and 10), the light spot propagates to the location of the second switching engine. The direction of the light spot is consistent with the direction of the light spot emitted by the first exchange engine.

In the embodiment of the application, because 8 lenses are shared in the dispersion direction between the two stages of switching engines in the wavelength selective switch, a 16f optical system is formed, and when an optical signal passes through the 16f optical system and reaches the second switching engine, the light spot distribution area is consistent with the area of the first switching engine projected by the optical signal, and the light spot distribution is within the switching area. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. Specifically, referring to fig. 8, fig. 8 is a schematic diagram of a simulated waveform of a filter bandwidth in an embodiment of the present application, where a dotted line corresponds to a two-stage cascaded 1xN wavelength selective switch, and a solid line corresponds to the wavelength selective switch provided in the embodiment of the present application. Illustratively, the wavelength selective switch proposed in the embodiments of the present application has a 3 decibel (dB) bandwidth of a filtered spectrum in a 50 gigahertz (GHz) channel of 44.2 GHz. The 3dB bandwidth of the filter spectrum of the 1xN two-stage cascaded wavelength selective switch designed by using the same grating and the same light spot size is 42.7GHz, and it can be seen that the filter spectrum bandwidth of the wavelength selective switch provided in the embodiment of the present application is greater than that of the 1xN two-stage cascaded wavelength selective switch designed by using the same light spot size. It should be noted that this is only one possible simulation experiment result, and other simulation experiment results may exist according to the actual optical elements and the arrangement between the optical elements, which is not limited herein. By arranging the lens group between the switching engines, the filtering cost of the wavelength selective switch is reduced, the filtering bandwidth of the wavelength selective switch is improved, and the channel quality is improved.

In addition to the wavelength selective switch with the structure similar to that of fig. 4a and 4b, the wavelength selective switch according to the embodiment of the present application may also have other structures, specifically, please refer to fig. 9, where fig. 9 is a schematic structural diagram of another wavelength selective switch according to the embodiment of the present application, and the wavelength selective switch according to the embodiment of the present application includes: input fiber collimation array, first dispersion component, first switching engine, first lens group, relay lens, second lens group, second switching engine, second dispersion component and output fiber collimation array, wherein: the input fiber collimating array, the first dispersion element, the first switching engine, the first lens group, the relay lens, the second lens group, the second switching engine, the second dispersion element, and the output fiber collimating array are similar to the embodiment shown in fig. 4b, and are not repeated here.

In the embodiment of the present application, because a + B lenses are shared in the dispersion direction between the two stages of switching engines in the wavelength selective switch, a (2(a + B)) f optical system is formed, and when an optical signal passes through the (2(a + B)) f optical system and reaches the second switching engine, the light spot distribution area is consistent with the area where the optical signal is projected on the first switching engine, and the light spot distribution is within the switching area. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. The first dispersion element opens the dispersion of the light beams from the input fiber collimation array, projects the light beams on the first switching engine according to different wavelengths, and combines the different light beams in the dispersion direction into one light beam after the light beams with different wavelengths pass through the second dispersion element. The first dispersion element and the second dispersion element are arranged, so that the deflection of the light beams with different wavelengths is realized.

Referring to fig. 10, fig. 10 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application, where the wavelength selective switch according to the embodiment of the present application includes: input fiber collimation array, third lens group, first dispersion component, first switching engine, first lens group, relay lens, second lens group, second switching engine, fourth lens group, second dispersion component and output fiber collimation array, wherein: similar to the embodiment shown in fig. 4b, the input fiber collimating array, the third lens group, the first dispersive element, the first switching engine, the first lens group, the relay lens, the second lens group, the second switching engine, the fourth lens group, the second dispersive element, and the output fiber collimating array are omitted for brevity. The first dispersing element is located between the third lens groups, the second dispersing element is located between the fourth lens groups, the position of the first dispersing element relative to the third lens groups, and the position of the second dispersing element relative to the fourth lens groups are determined by the optical performance parameters of the respective optical elements, and are not limited herein.

In the embodiment of the present application, because a + B lenses are shared in the dispersion direction between the two stages of switching engines in the wavelength selective switch, a (2(a + B)) f optical system is formed, and when an optical signal passes through the (2(a + B)) f optical system and reaches the second switching engine, the light spot distribution area is consistent with the area where the optical signal is projected on the first switching engine, and the light spot distribution is within the switching area. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. The first dispersion element opens the dispersion of the light beams from the input fiber collimation array, projects the light beams on the first switching engine according to different wavelengths, and combines the different light beams in the dispersion direction into one light beam after the light beams with different wavelengths pass through the second dispersion element. The first dispersion element and the second dispersion element are arranged, so that the deflection of the light beams with different wavelengths is realized. By arranging the third lens group and the fourth lens group, the compensation of chromatic dispersion and chromatic aberration is provided for optical signals in the wavelength switch, and the optical performance of the wavelength switch is improved.

Referring to fig. 11, fig. 11 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application, where the wavelength selective switch according to the embodiment of the present application includes: input fiber collimation array, first exchange engine, first battery of lenses, third dispersion element, relay lens, second battery of lenses, fourth dispersion element, second exchange engine and output fiber collimation array, wherein: the input fiber collimating array, the first switching engine, the first lens group, the third dispersive element, the relay lens, the second lens group, the fourth dispersive element, the second switching engine, and the output fiber collimating array are similar to the embodiment shown in fig. 4b, and are not repeated here. The third dispersive element is located between the first lens groups, and the fourth dispersive element is located between the second lens groups, which are determined by respective optical parameters, and are not limited herein.

In the embodiment of the present application, because a + B lenses are shared in the dispersion direction between the two stages of switching engines in the wavelength selective switch, a (2(a + B)) f optical system is formed, and when an optical signal passes through the (2(a + B)) f optical system and reaches the second switching engine, the light spot distribution area is consistent with the area where the optical signal is projected on the first switching engine, and the light spot distribution is within the switching area. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. Through setting up third dispersive element and fourth dispersive element, effectively reduce the light beam and produce extra off-axis aberration when transmitting, promote optical property.

Referring to fig. 12, fig. 12 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present disclosure, where the wavelength selective switch according to the embodiment of the present disclosure includes: input fiber collimation array, third lens group, first dispersion component, first exchange engine, first lens group, third dispersion component, relay lens, second lens group, fourth dispersion component, second exchange engine, fourth lens group, second dispersion component and output fiber collimation array, wherein: similar to the embodiment shown in fig. 4b, the input fiber collimating array, the third lens group, the first dispersive element, the first switching engine, the first lens group, the third dispersive element, the relay lens, the second lens group, the fourth dispersive element, the second switching engine, the fourth lens group, the second dispersive element, and the output fiber collimating array are not described herein again. The first dispersive element is positioned between the third lens groups, the second dispersive element is positioned between the fourth lens groups, the third dispersive element is positioned between the first lens groups, the fourth dispersive element is positioned between the second lens groups, and the specific position is determined by respective optical performance parameters.

In the embodiment of the present application, because a + B lenses are shared in the dispersion direction between the two stages of switching engines in the wavelength selective switch, a (2(a + B)) f optical system is formed, and when an optical signal passes through the (2(a + B)) f optical system and reaches the second switching engine, the light spot distribution area is consistent with the area where the optical signal is projected on the first switching engine, and the light spot distribution is within the switching area. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. The first dispersion element opens the dispersion of the light beams from the input fiber collimation array, projects the light beams on the first switching engine according to different wavelengths, and combines the different light beams in the dispersion direction into one light beam after the light beams with different wavelengths pass through the second dispersion element. The first dispersion element and the second dispersion element are arranged, so that the deflection of the light beams with different wavelengths is realized. The first dispersion element and the second dispersion element are arranged, so that the deflection of the light beams with different wavelengths is realized. By arranging the third lens group and the fourth lens group, the compensation of chromatic dispersion and chromatic aberration is provided for optical signals in the wavelength switch, and the optical performance of the wavelength switch is improved. By arranging the third dispersive element and the fourth dispersive element, extra off-axis aberration generated by the light beam during transmission is effectively reduced, and the optical performance of the wavelength switch is improved.

Referring to fig. 13, fig. 13 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application, where the wavelength selective switch according to the embodiment of the present application includes: input fiber collimation array, first exchange engine, seventh lens battery, first lens battery, relay lens, second lens battery, eighth lens battery, second exchange engine and output fiber collimation array, wherein: the input fiber collimation array, the first switching engine, the first lens assembly, the relay lens, the second lens assembly, the second switching engine, and the output fiber collimation array are similar to the embodiment corresponding to fig. 4b, and are not described herein again.

The seventh lens group includes U lenses, the eighth lens group includes U lenses, and U is a natural number greater than or equal to 2. The lenses of the seventh lens group and the eighth lens group can be only lenses with curvature in the dispersion direction, can also be only lenses with curvature in the exchange optical path direction, and can also be lenses with curvature in the dispersion direction and curvature in the exchange optical path direction at the same time, and the sum of the distances between the lenses in the seventh lens group is equal to the sum of the focal lengths of the lenses in the seventh lens group; the distance between the lens closest to the first exchange engine in the seventh lens group and the first exchange engine is equal to the focal length of the lens; the sum of distances between lenses in the eighth lens group is equal to the sum of focal lengths of lenses in the eighth lens group; and the distance between the lens in the eighth lens group closest to the second interchange engine and the second interchange engine is equal to the focal length of the lens.

In the embodiment of the present application, between two stages of switching engines in a wavelength selective switch, when the seventh lens group and the eighth lens group include lenses having curvatures in the dispersion direction, there are (a + B + G + H) lenses in total in the dispersion direction, and a (2(a + B + G + H)) f optical system is formed, and after an optical signal passes through the (2(a + B + G + H)) f optical system, a light spot distribution region when the optical signal reaches the second switching engine is consistent with a region where the optical signal is projected on the first switching engine, and the light spot distribution is within the switching region. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. By arranging the seventh lens group and the eighth lens group, chromatic dispersion and chromatic aberration compensation is provided for optical signals in the wavelength switch, and the optical performance of the wavelength switch is improved.

Referring to fig. 14, fig. 14 is a schematic structural diagram of another wavelength selective switch according to an embodiment of the present application, where the wavelength selective switch according to the embodiment of the present application includes: input fiber collimation array, third lens group, first dispersion component, first exchange engine, seventh lens group, first lens group, relay lens, second lens group, eighth lens group, second exchange engine, fourth lens group, second dispersion component and output fiber collimation array, wherein: similar to the embodiment shown in fig. 4b, the input fiber collimating array, the third lens group, the first dispersive element, the first switching engine, the first lens group, the relay lens, the second lens group, the second switching engine, the fourth lens group, the second dispersive element, and the output fiber collimating array are omitted for brevity. The seventh lens group and the eighth lens group are similar to the embodiment shown in FIG. 13, and are not described again here. The first dispersive element is positioned between the third lens groups, the second dispersive element is positioned between the fourth lens groups, the third dispersive element is positioned between the first lens groups, the fourth dispersive element is positioned between the second lens groups, and the specific position is determined by respective optical performance parameters.

In the embodiment of the present application, between two stages of switching engines in a wavelength selective switch, when the seventh lens group and the eighth lens group include lenses having curvatures in the dispersion direction, there are (a + B + G + H) lenses in total in the dispersion direction, and a (2(a + B + G + H)) f optical system is formed, and after an optical signal passes through the (2(a + B + G + H)) f optical system, a light spot distribution region when the optical signal reaches the second switching engine is consistent with a region where the optical signal is projected on the first switching engine, and the light spot distribution is within the switching region. Therefore, the second switching engine has a weak cutting effect on the light spots, and the filtering cost is effectively reduced. The first dispersion element opens the dispersion of the light beams from the input fiber collimation array, projects the light beams on the first switching engine according to different wavelengths, and combines the different light beams in the dispersion direction into one light beam after the light beams with different wavelengths pass through the second dispersion element. The first dispersion element and the second dispersion element are arranged, so that the deflection of the light beams with different wavelengths is realized. By arranging the third lens group, the fourth lens group, the seventh lens group and the eighth lens group, the chromatic dispersion and chromatic aberration compensation is provided for optical signals in the wavelength switch, and the optical performance of the wavelength switch is improved.

The terms "first," "second," and the like in the description and in the claims of the present application and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Moreover, the terms "comprises," "comprising," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or modules is not necessarily limited to those steps or modules explicitly listed, but may include other steps or modules not expressly listed or inherent to such process, method, article, or apparatus. The naming or numbering of the steps appearing in the present application does not mean that the steps in the method flow have to be executed in the chronological/logical order indicated by the naming or numbering, and the named or numbered process steps may be executed in a modified order depending on the technical purpose to be achieved, as long as the same or similar technical effects are achieved.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A wavelength selective switch, comprising: the optical fiber switching system comprises an input optical fiber collimation array, a first switching engine, a relay lens, a first lens group, a second switching engine and an output optical fiber collimation array;

the input fiber collimation array comprises a plurality of input ports;

the first switching engine is connected with the input optical fiber collimation array;

the relay lens is connected with the first switching engine and the second switching engine, the relay lens is positioned between the first switching engine and the second switching engine, and the relay lens is a lens in the direction of a switching optical path;

the first lens group comprises A lenses, the second lens group comprises B lenses, A is a natural number which is greater than or equal to 2, B is a natural number which is greater than or equal to 2, the first lens group connects the first switching engine and the relay lens, the second lens group connects the relay lens and the second switching engine, the first lens group at least comprises a lens with curvature in the dispersion direction, and the second lens group at least comprises a lens with curvature in the dispersion direction;

the output fiber alignment array comprises a plurality of output ports, and the output fiber alignment array is connected with the second switching engine.

2. The wavelength selective switch of claim 1,

the sum of the distances between the lenses in the first lens group is equal to the sum of the focal lengths of the lenses in the first lens group;

the distance between the lens closest to the relay lens in the first lens group and the relay lens is equal to the focal length of the lens closest to the relay lens in the first lens group;

the sum of the distances between the lenses in the second lens group is equal to the sum of the focal lengths of the lenses in the second lens group;

the lens in the second lens group closest to the relay lens is away from the relay lens by a distance equal to the focal length of the lens in the second lens group closest to the relay lens;

the sum of A and B is an even number.

3. The wavelength selective switch of claim 2,

the sum of the focal lengths of the lenses in the first lens group is equal to the focal length of the relay lens;

the sum of the focal lengths of the lenses in the second lens group is equal to the focal length of the relay lens.

4. The wavelength selective switch of claim 3, further comprising: a first dispersion element and a second dispersion element;

the first dispersion element is connected with the input fiber collimation array and the first switching engine, and the first dispersion element is positioned between the input fiber collimation array and the first switching engine;

the second dispersive element is connected to the second switching engine and the output fiber collimating array, and the second dispersive element is located between the second switching engine and the output fiber collimating array.

5. The wavelength selective switch of claim 4, further comprising: a third lens group and a fourth lens group;

the third lens group includes C lenses, the fourth lens includes D lenses, C is a natural number greater than or equal to 2, and D is a natural number greater than or equal to 2;

the third lens group is connected with the input optical fiber collimation array and the first switching engine, and the first dispersion element is positioned between the lenses of the third lens group;

the fourth lens group is connected with the second switching engine and the second dispersion element, the fourth lens group is connected with the second dispersion element and the output optical fiber collimation array, and the second dispersion element is located between lenses of the fourth lens group.

6. The wavelength selective switch of claim 5,

the sum of the distances between the lenses in the third lens group is equal to the sum of the focal lengths of the lenses in the third lens group;

the distance between the lens in the third lens group closest to the first interchange engine and the first interchange engine is equal to the focal length of the lens in the third lens group closest to the first interchange engine;

the sum of the distances between the lenses in the fourth lens group is equal to the sum of the focal lengths of the lenses in the fourth lens group;

the distance between the lens in the fourth lens group closest to the second interchange engine and the second interchange engine is equal to the focal length of the lens in the third lens group closest to the first interchange engine;

the sum of C and D is an even number.

7. The wavelength selective switch according to any one of claims 3 or 6, further comprising: a third dispersion element and a fourth dispersion element;

the third dispersive element is located between the first switching engine and the relay lens;

the fourth dispersive element is located between the relay lens and the second switching engine.

8. The wavelength selective switch of claim 7, further comprising: a fifth lens group and a sixth lens group;

the fifth lens group includes E lenses, the sixth lens includes F lenses, E is a natural number greater than or equal to 2, and F is a natural number greater than or equal to 2;

the fifth lens group is connected with the first exchange engine and the first lens group, and the third chromatic dispersion element is positioned between lenses of the fifth lens group;

the sixth lens group is connected with the second lens group and the second exchange engine, and the fourth dispersion element is located between lenses of the sixth lens group.

9. The wavelength selective switch of claim 8,

the sum of the distances between the lenses in the fifth lens group is equal to the sum of the focal lengths of the lenses in the fifth lens group;

the distance between the lens in the fifth lens group closest to the first interchange engine and the first interchange engine is equal to the focal length of the lens in the fifth lens group closest to the first interchange engine;

the sum of distances between lenses in the sixth lens group is equal to the sum of focal lengths of lenses in the sixth lens group;

the distance between the lens in the sixth lens group closest to the second interchange engine and the second interchange engine is equal to the focal length of the lens in the sixth lens group closest to the second interchange engine;

the sum of E and F is an even number.

10. The wavelength selective switch according to claim 7, wherein the wavelength selective switch specifically comprises:

the third dispersing element is connected with the first lens group, and the third dispersing element is positioned between the first lens group;

the fourth dispersion element is connected with the second lens group, and the fourth dispersion element is located between the second lens group.

11. The wavelength selective switch according to any one of claims 3 or 6, further comprising: a seventh lens group and an eighth lens group;

the seventh lens group is connected with the first switching engine and the first lens group;

the eighth lens group is connected with the second lens group and the second switching engine;

the seventh lens group includes G lenses, the eighth lens group includes H lenses, U is a natural number greater than or equal to 2, and G is a natural number greater than or equal to 2.

12. The wavelength selective switch of claim 11,

the sum of distances between lenses in the seventh lens group is equal to the sum of focal lengths of lenses in the seventh lens group;

the distance between the lens in the seventh lens group closest to the first interchange engine and the first interchange engine is equal to the focal length of the lens in the seventh lens group closest to the first interchange engine;

the sum of distances between lenses in the eighth lens group is equal to the sum of focal lengths of lenses in the eighth lens group;

the lens in the eighth lens group closest to the second interchange engine is away from the second interchange engine by a distance equal to the focal length of the lens in the eighth lens group closest to the second interchange engine;

the sum of G and H is an even number.

13. An optical splitter, comprising: the wavelength selective switch of any one of claims 1-12.

14. A reconfigurable optical add/drop multiplexer, the reconfigurable optical add/drop multiplexer comprising: the wavelength selective switch of any one of claims 1-12.