CN117031636A

CN117031636A - Wavelength selective switch with Tain structure and intelligent optical network device

Info

Publication number: CN117031636A
Application number: CN202311289445.1A
Authority: CN
Inventors: 万助军; 何楠; 葛柯廷
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2023-10-08
Filing date: 2023-10-08
Publication date: 2023-11-10
Anticipated expiration: 2043-10-08
Also published as: CN117031636B

Abstract

The invention discloses a wavelength selective switch with a Tain structure and an intelligent optical network device, which comprise an optical front end FAU, a cylindrical reflector, a combined cylindrical lens, a grating and an optical exchange engine; the FAU, the grating and the optical exchange engine are all arranged on the focal plane of the cylindrical reflector, and the combined cylindrical lens is arranged on the optical path between the cylindrical reflector and the grating and is close to the grating; the FAU comprises an optical fiber array, a microlens column lens and a polarization diversity component, wherein the polarization diversity component comprises a Wollaston prism and a half-wave plate. The combined cylindrical lens is formed by vertically or horizontally arranging two identical cylindrical lenses. The cylindrical mirror and the combined cylindrical lens are orthogonal to each other in the focusing direction, the former focuses the light beam in the horizontal plane, and the latter focuses the light beam in the vertical plane. The light beams entering from two input ends of the WSS with the Twin structure are respectively incident on the upper half area and the lower half area of the optical exchange engine through the action of the combined cylindrical lens, so that the two WSS are independently controlled through one optical exchange engine.

Description

Wavelength selective switch with Tain structure and intelligent optical network device

Technical Field

The invention relates to an optical device applied to the field of optical fiber communication, in particular to an optical device capable of distributing various channels in a DWDM optical signal to any port according to different wavelengths.

Background

With rapid progress in technology, data volume increases exponentially, and thus, a small pressure is applied to the communication capacity of a network. Meanwhile, the 5G technology is mature and popularized, and the development of big data services such as the Internet of things and cloud computing is greatly promoted, so that the bandwidth demand is increased. The support of the core optical network is needed behind the wireless transmission, so the pressure of the increase of the data volume inevitably leads to the risk that the conventional optical network will be blocked in the near future, and the upgrading and the expansion are needed. Dense wavelength division multiplexing (Dense Wavelength Division Multiplexing, DWDM) and reconfigurable optical add-Drop multiplexing (ROADM) technologies that are originally applied in backbone networks need to sink to metropolitan area networks.

The ROADM node can forward or download/upload any wavelength combination through remote software operation, plays a role in flexibly controlling service wavelength, upgrades the originally fixed switching mode to dynamic programming, and is a key technology for ensuring the flexibility and reconfigurability of the optical fiber communication network nowadays. Currently mainstream ROADM nodes are usually constructed by wavelength selective switches (Wavelength Selective Switch, WSS), which is a 1×n port optical device that can switch any one set of wavelengths in an input port to any one output port. In each interconnect direction of ROADM nodes, two WSSs need to be configured for transmission/reception, and in order to reduce the size and reduce the cost, a Twin structure WSS may be employed. Twin WSS integrates two WSS functions in one device, reducing cost and size by sharing various optical elements therein.

In the existing Twin WSS, two wedge prisms or a roof prism are usually added in the optical path, so that the input light of the two WSS is respectively incident on the upper half area and the lower half area of the optical exchange engine, and therefore, a corresponding optical path adapting element is required to be added, and the structure is complex.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a wavelength selective switch with a Tain structure and an intelligent optical network device, and aims to solve the problem that in the prior art, a prism is required to be added in an optical path to cause the structure to be complex.

The invention provides a wavelength selective switch with a Tain structure, which comprises an optical front end FAU, a cylindrical reflector, a combined cylindrical lens, a grating and an optical exchange engine which are sequentially arranged; the optical front end FAU, the grating and the optical exchange engine are all arranged on the focal plane of the cylindrical reflector, and the combined cylindrical lens is arranged on the optical path between the cylindrical reflector and the grating and is close to the grating; the light beams entering from the two input ends of the Twin structure are respectively incident on the upper half area and the lower half area of the optical exchange engine through the action of the combined cylindrical lens, so that the two WSS are independently controlled through one optical exchange engine.

Still further, the optical front-end FAU includes: an optical fiber array, a microlens, and a polarization diversity assembly sequentially disposed along the optical path; when the device works, input light passes through the micro lens array and the micro cylindrical lens respectively, light spots are shaped into elliptical light spots, and then the elliptical light spots are divided into two polarized light beams with included angles through the polarization diversity component.

Still further, the polarization diversity assembly includes a Wollaston prism and a half wave plate; the Wollaston prism is used for dividing input light into p light and s light with a certain included angle, and the half-wave plate is arranged on the p light path, so that the two light beams become the same polarization state.

Further, the combined cylindrical lens comprises two identical first cylindrical lenses and two identical second cylindrical lenses, and the first cylindrical lenses and the second cylindrical lenses are stacked.

As an embodiment of the invention, the first cylindrical lens and the second cylindrical lens are vertically aligned along the x-axis, the first cylindrical lens axis is aligned with the middle position of the lower half of the light exchange engine, and the second cylindrical lens axis is aligned with the middle position of the upper half of the light exchange engine.

As another embodiment of the present invention, the first cylindrical lens and the second cylindrical lens are arranged side by side end to end and in the y-axis direction.

Further, the cylindrical reflector and the combined cylindrical lens are orthogonal to each other in the focusing direction, the cylindrical reflector focuses the light beam in a horizontal plane, and the combined cylindrical lens focuses the light beam in a vertical plane.

Still further, the grating may be a blazed grating, a phase grating, or a prismatic grating.

Still further, the optical switching engine may employ an LCOS chip or MEMS chip or a liquid crystal array+crystal wedge structure.

The invention also provides an intelligent optical network device comprising the wavelength selective switch.

Compared with the prior art, the technical scheme of the invention has the advantages that as the combined cylindrical lenses are arranged skillfully, two groups of input light energy are respectively incident on the upper half area and the lower half area of the optical exchange engine, two WSS can be independently controlled without adding redundant elements, and the structure is greatly simplified.

Drawings

Fig. 1 is a schematic diagram of a Twin WSS with a vertical arrangement of cylindrical lenses according to an embodiment of the present invention;

FIG. 2 is a schematic view of the vertical arrangement and axial position of cylindrical lenses according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of an input/output port arrangement corresponding to a vertical arrangement according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a Twin WSS with horizontally arranged cylindrical lenses according to an embodiment of the present invention;

FIG. 5 is a schematic view of a horizontal arrangement and an axial position of cylindrical lenses according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of an input/output port arrangement corresponding to a horizontal arrangement according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of the optical path of a Twin WSS with polarization diversity added in a vertical arrangement according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of polarization diversity components in vertical alignment according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of an optical path of a Twin WSS with polarization diversity added in a horizontal arrangement according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of polarization diversity components in horizontal arrangement according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of light spot distribution on LCOS in a Twin WSS provided by an embodiment of the present invention;

fig. 12 is an overall structure diagram of a reflective Twin WSS provided in an embodiment of the present invention;

wherein the x-axis is vertical and the y-axis is horizontal.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

The invention provides a novel Twain WSS structure, which integrates two WSSs in one module on the basis of not adding optical elements, and has the characteristics of simple structure, small volume and low cost.

The wavelength selective switch provided by the embodiment of the invention is mainly applied to intelligent optical network devices, and the wavelength selective switch WSS structure of the Twin structure provided by the embodiment of the invention consists of an optical front end (FAU), a cylindrical reflector, a combined cylindrical lens, a grating and an optical exchange engine.

The FAU, the grating and the optical exchange engine are all arranged on the focal plane of the cylindrical reflector, and the combined cylindrical lens is arranged on the optical path between the cylindrical reflector and the grating and is close to the grating. The FAU is composed of an optical fiber array, a microlens column lens and a polarization diversity component, wherein the polarization diversity component comprises a Wollaston prism and a half-wave plate. The combined cylindrical lens is formed by stacking two identical cylindrical lenses up and down or left and right. The cylindrical mirror and the combined cylindrical lens are orthogonal to each other in the focusing direction, the former focuses the light beam in the horizontal plane, and the latter focuses the light beam in the vertical plane. The grating may be a blazed grating, a phase grating or a more dispersive prism grating. The optical switching engine may employ a liquid crystal on silicon (Liquid Crystal on Silicon, LCOS) chip, a microelectromechanical system (Micro Electro Mechanical System, MEMS) chip, or a liquid crystal array + crystal wedge structure. The MEMS micro-mirror array controls the reflection direction of one wavelength through each micro-mirror, and selects an output port; LCOS is a spatial light modulator, which controls the diffraction angle of each wavelength through wave front regulation and control, and selects an output port; the liquid crystal box and the crystal wedge are used for controlling the refraction direction of each wavelength by the polarization regulation and control of liquid crystal and matching with the crystal wedge, and an output port is selected.

The WSS is a 1×n port optical device, and its input/output ports are all dense wavelength division multiplexing (Dense Wavelength Division Multiplexing, DWDM) ports, and any one or a group of wavelengths in the input ports can be switched to any one of the output ports, that is, the WSS has an optical switching function with wavelengths as granularity. The WSS has a channel equalization function, and can control the attenuation of each channel and equalize the input DWDM signals with unbalanced power to the same power level.

The WSS optical layer is typically formed of optical elements such as an optical switching engine, grating, lens, prism, birefringent crystal, waveplate, microlens array, and fiber array, with a control circuit layer beneath the optical layer.

The input wavelength division multiplexing (Wavelength Division Multiplexing, WDM) light beam is separated into two beams by a crystal group and converted into the same polarization state, the two beams are incident on a diffraction grating through a reflector and a lens, light with different wavelengths is diffracted into different angles, the light is incident on an LCOS chip through the lens and the reflector, the different wavelengths are incident on different areas of the LCOS chip, a liquid crystal unit on the LCOS controls the angle of the reflected light beam by adjusting the wave front of the light beam, the polarization state is recovered through the reflector and the crystal group, and the light beams with different wavelengths are coupled into respective target optical fibers. The light beams with various wavelengths are reflected in different areas of the LCOS chip, and the liquid crystal units on the chip can independently control the various wavelengths, so that the device can switch any wavelength combination into any output optical fiber and has a channel equalization function.

LCOS is a Liquid Crystal (LC) chip with active silicon chip as substrate, and is used in the field of Liquid Crystal display for the first time, and a plurality of control units are arranged on the silicon chip, so that the phase of the reflected light of each unit can be controlled by changing the bias voltage of the Liquid Crystal material on the upper part of each unit. Light with different wavelengths is incident to different areas on the LCOS chip and reflected, and the phases of the reflected light at each point are independently controlled, namely the wave front is adjusted, so that the angle of the reflected light can be controlled.

Currently, ROADM nodes in intelligent optical networks are required to have wavelength independent/direction independent/blocking free (CDC) functions. The current mainstream technical scheme is that multicast switches (Multi Cast Switch, MCS) are adopted in the branching units of the nodes; and the line unit adopts a 1×n port WSS. It is currently generally necessary to process the c+l broadband beams simultaneously, which is difficult to achieve using only one set of WSSs, and thus two WSS modules are required for each interconnect direction. To reduce WSS module cost and save cabinet space, two WSSs may be integrated into one module, which is a two-in-one WSS, commonly referred to in the industry as a Twin WSS.

Twin WSS integrates two separate high performance switching elements into one compact package and control interface that shares the optical and electronic control circuitry, including diffraction gratings, various prisms, and LCOS systems, which adds only a bit to the construction cost over a single system. The Tain WSS can support wavelength exchange in one routing direction, the connection ports are in line with wavelength independence/direction independence/non-blocking functions in the add-drop direction and the up/down direction, a certain node breaks down to only affect one direction connected with the node, and all other connection directions are allowed to continue to run, so that wiring is simplified, and the need of manual reconfiguration is avoided.

For further explanation of embodiments of the present invention, the following will be described in detail with reference to the accompanying drawings:

the invention provides a wavelength selective switch WSS structure of a novel Tain structure, which is shown in a figure 1, and comprises an optical front end FAU1, a cylindrical reflector 2, a combined cylindrical lens 3, a grating 4 and an optical exchange engine 5; the optical front end FAU1, the grating 4 and the optical exchange engine 5 are all arranged on the focal plane of the cylindrical reflector 2, and the combined cylindrical lens 3 is arranged on the optical path between the cylindrical reflector 2 and the grating 4 and is close to the grating 4; the light beams entering from the two input ends of the Twin structure are respectively incident on the upper half area and the lower half area of the optical exchange engine through the action of the combined cylindrical lens, so that the two WSS are independently controlled through one optical exchange engine.

The optical front end FAU1 is composed of an optical fiber array 11, a microlens array 12, a microlens column lens 13, and a polarization diversity assembly 14, wherein the polarization diversity assembly 14 includes a wollaston prism 141 and a half-wave plate 142. The combined cylindrical lens 3 is formed by stacking two identical first cylindrical lenses 31 and second cylindrical lenses 32 one above the other or left and right. The cylindrical mirror 2 is orthogonal to the focusing direction of the combined first cylindrical lens 31 and second cylindrical lens 32, the former focusing the light beam in the horizontal plane and the latter focusing the light beam in the vertical plane. The grating 4 may be a blazed grating, a phase grating or a more dispersive prism grating. The optical switch engine 5 may employ an LCOS (liquid crystal on silicon) chip, a MEMS (micro electro mechanical system) chip, or a liquid crystal array + crystal wedge structure.

Wherein the input/output assembly is composed of an input/output optical fiber array 11, a microlens array 12 and a microlens 13, the dispersion assembly is composed of a grating 4 and a cylindrical mirror 2, and the port switching is realized by an optical switching engine 5 and a combined cylindrical lens 3. The dispersive element adopts a prism grating Grism instead of a plane grating, so that incidence and diffraction angles of light beams on a grating surface can be reduced, diffraction efficiency is improved, and light path layout is facilitated. The optical switching engine adopts LCOS, because LCOS can be flexibly and dynamically programmed compared with MEMS micro-mirror array technology, and flexible grid (F) function is perfectly supported. Considering that the optical signal on the fiber link is randomly polarized, the optical switching engine 5, such as LCOS, can only handle linearly polarized light, and thus a polarization diversity assembly 14 is provided. In this optical system, the dispersion system in the yz plane is a 4f system (with respect to the cylindrical mirror 2); while the port switching system in the xz plane is a 2f system (with respect to the first and second cylindrical lenses 31 and 32). In order to realize the matching of the beam size and the focal length, the mirror image effect of the prism grating is borrowed in the xz plane, the double-cemented cylindrical lens becomes a combined lens, and the effective focal length of the combined lens can be adjusted through the distance between the double-cemented cylindrical lens and the prism grating.

The principle of the Tain WSS is that the elements such as a grating, various prisms, an LCOS light exchange engine and the like are shared, and the deflection of the light path is respectively controlled through the upper and lower partitions of the LCOS. As shown in FIG. 1, the Twain structure can be realized by skillfully using two identical first cylindrical lenses 31 and second cylindrical lenses 32 which are abutted against each other and arranged along the vertical direction of LCOS, and as shown in FIG. 2, the axes of the two cylindrical lenses are respectively aligned with the middle positions of the upper half and the lower half of LCOS. Fig. 3 shows the arrangement of the ports of the corresponding optical fiber array 1 in the structure, and the input and output ports are divided into two groups and are also arranged along the vertical direction of the LCOS, wherein the input ports are distributed at two ends to avoid mutual crosstalk. Because the Tain structure has two groups of WSS at the same time, the ports are distinguished to belong to different WSS structures by using (1) and (2) in the figure; wherein (1) in, (1) out1, (1) out2, (1) out3 and (1) out7 respectively represent the input and output ports of the first set of WSS, (2) in, (2) out1, (2) out2, (2) out3 and (1) out7 respectively represent the input and output ports of the second set of WSS).

As shown in fig. 4, the first cylindrical lens 31 and the second cylindrical lens 32 may be arranged in parallel along the y-axis direction, where the Twin structure may be implemented, and the parallel arrangement of ports may implement an effect of doubling the number of WSS ports. Fig. 5 shows the axial positions of the first cylindrical lens 31 and the second cylindrical lens 32 in this configuration, which are also aligned with the middle positions of the upper and lower half regions of the LCOS, respectively, except that the cylindrical lenses become aligned in the horizontal direction of the LCOS. Fig. 6 is a corresponding input/output port arrangement, which is divided into two columns and arranged along the LCOS horizontal direction, wherein the input ports are distributed at two ends to avoid mutual crosstalk, and the input/output of the same WSS (distinguished from fig. 3 by (1), (2)) is not in the same column, because the input/output positions of the Twin structure are exchanged in the optical path.

Fig. 7 is a schematic diagram of an optical path of the structure of fig. 1 after polarization diversity is added, input light is split into two beams of linear polarized light through a polarization component 14, then is dispersed and split through a cylindrical mirror 2, a first cylindrical lens 31 and a grating 4, then is focused by a mirror image of the cylindrical mirror 2 about the grating 4, is hit on an LCOS chip 5, is reflected back from an upper position and a lower position in a switching manner, passes through a second cylindrical lens 32 in a reflecting manner, and finally is injected into a front end 1 of an FAU to be recombined, and is switched to any output port. Under the Twin structure, the other input optical path is completely symmetrical, that is, after passing through the polarization diversity component 14, the two beams of linear polarized light sequentially pass through the combined cylindrical reflector 2, the second cylindrical lens 32, the grating 4 and the mirror image of the second cylindrical lens 32 about the grating 4, reach the LCOS chip 5, and then are exchanged and reflected back up and down, and pass through the first cylindrical lens 31 (because the first cylindrical lens 31 and the second cylindrical lens 32 are vertically arranged in the structure, the two cylindrical lenses overlap in the yz plane of fig. 7). Thus, the extra optical element is skillfully not increased to achieve the Tain structure.

Fig. 8 is an enlarged view of an optical path of the polarization diversity assembly 14 when the cylindrical lenses are vertically arranged, the input light passes through the microlens array 12 and the microlens 13, respectively, the light spots are shaped into elliptical light spots, the elliptical light spots are divided into two beams of p light and s light with different polarization states by the wollaston prism 141, and then the p light is required to be changed into the s light with the same polarization state by the half wave plate 142. Where the ports are arranged vertically as can be seen from fig. 3, so that in fig. 8 the two input light paths overlap.

Fig. 9 is a schematic view of the optical path of the structure of fig. 2 after polarization diversity is added, and the horizontal arrangement of the cylindrical lenses is reflected in the figure as two first cylindrical lenses 31 and second cylindrical lenses 32 which are symmetrical up and down. The two groups of input light are respectively incident from the upper and lower positions at a certain angle and are reflected back through the upper and lower positions exchanged by the LCOS chip 5.

Fig. 10 is an enlarged view of the optical path of the polarization diversity module 14 using the wollaston prism when the cylindrical lenses are horizontally arranged, and the difference between fig. 8 is that the microlens array 12 is changed from one column to two columns in the yz plane, which corresponds to the input/output port arrangement schematic diagram of fig. 6, and features that the number of WSS ports can be doubled when the cylindrical lenses are vertically arranged. And two groups of light are input in parallel under the Tain structure, and are uniformly divided into two beams of light with different polarizations, and the two groups of parallel light generate symmetrical output with a certain included angle. The inclusion of this angle enables the optical path up-down switching in fig. 9.

Fig. 11 is a schematic diagram of light spot distribution on an LCOS under a Twin structure, light spots of two sets of WSSs respectively strike upper and lower half areas (distinguished along the y direction) of the LCOS, and different channels are uniformly arranged along the horizontal direction (x direction) according to wavelengths. Due to shaping of the optical front end, the spot takes the shape of an ellipse, i.e. The large light spot is formed in the yz plane of the dispersion system, the influence of aberration is small, and the system efficiency is high; the port switching system xz is small in light spot, so that the number of channels which can be processed simultaneously is more, the limiting factor is larger, and the passband characteristic is more excellent.

In practical application, the WSS needs to be designed into a Twin structure, two WSS functions are integrated in one box, and the size needs to be controlled, so that only one card slot in the cabinet can be occupied. For this purpose, the actual optical structure is composed of a Fiber Array (FA) 11, a microlens Array 12, a microlens 13, a polarization diversity module 14, a cylindrical mirror 2, a combined cylindrical lens 3, a grating 4 (Grism prism grating), and an LCOS (liquid crystal on silicon) chip 5, as shown in fig. 12. The cylindrical reflector 2 is adopted to fold the optical path, so that the optical layer size of the WSS can be reduced by nearly one time.

The WSS performs dispersion spectroscopy using a transmission grating, so that each wavelength beam is spread in the horizontal direction. Let the number of lines of the grating be l, the grating constant be d, and the Littrow angle beThe line dispersion of the grating in this system is +.>

The diffraction length change per nm wavelength is shown. Now introduce communication parameters, let->For the channel bandwidth>At the center wavelength, the channel spacing is

Combining the two formulas to obtain the channel spacing P on LCOS as

Thus, the limiting factor in the horizontal direction is

The limiting factor parameter is introduced because the laser output laser wavelength has certain drift, and when the limiting factor is more than 2.5, the loss influence caused by the movement of the light spot in the LCOS channel spacing due to the wavelength drift is smaller.

In addition, the passband performance of the WSS system varies with the limiting factor as follows:

wherein,for the pass band performance index parameter, < >>For the channel bandwidth parameter, erf is shorthand for the error function, pm is the channel spacing on the LCOS, and Dm is the pixel area width on the LCOS allocated to each channel. When the beam limiting factor is larger than 2.5, the flatness of the pass band and the gradient coefficient of the side band of the system are good, and the system requirement can be met.

It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. The wavelength selective switch with the Tain structure is characterized by comprising an optical front end FAU (1), a cylindrical reflector (2), a combined cylindrical lens (3), a grating (4) and an optical exchange engine (5) which are sequentially arranged;

the optical front end FAU (1), the grating (4) and the optical exchange engine (5) are all arranged on the focal plane of the cylindrical reflector (2), and the combined cylindrical lens (3) is arranged on the optical path between the cylindrical reflector (2) and the grating (4) and is close to the grating (4);

light beams entering from two input ends of the Twin structure are respectively incident on the upper half area and the lower half area of the optical exchange engine (5) through the action of the combined cylindrical lens (3), so that two WSS are independently controlled through one optical exchange engine.

2. The wavelength selective switch according to claim 1, wherein the optical front-end FAU (1) comprises: an optical fiber array (11), a microlens array (12), a microlens (13) and a polarization diversity assembly (14) which are sequentially arranged along the optical path;

when the device works, input light passes through the micro lens array (12) and the micro cylindrical lens (13) respectively, light spots are shaped into elliptical light spots, and then the elliptical light spots are divided into two polarized light beams with included angles through the polarization diversity component (14).

3. The wavelength selective switch according to claim 2, wherein the polarization diversity component (14) comprises a wollaston prism (141) and a half-wave plate (142);

the Wollaston prism (141) is used for dividing input light into p light and s light with a certain included angle, and the half-wave plate (142) is arranged on a p light path so that two light beams become the same polarization state.

4. The wavelength selective switch according to claim 1, wherein the combined cylindrical lens (3) comprises two identical first cylindrical lenses (31) and second cylindrical lenses (32), the first cylindrical lenses (31) and the second cylindrical lenses (32) being arranged in a stack.

5. The wavelength selective switch according to claim 4, wherein the first cylindrical lens (31) and the second cylindrical lens (32) are vertically aligned along the x-axis, the first cylindrical lens (31) axis being aligned with the middle position of the lower half of the light exchange engine (5), and the second cylindrical lens (32) axis being aligned with the middle position of the upper half of the light exchange engine (5).

6. The wavelength selective switch according to claim 4, wherein said first cylindrical lens (31) and said second cylindrical lens (32) are also arranged end-to-end and in parallel along the y-axis.

7. Wavelength selective switch according to claim 1, characterized in that the cylindrical mirror (2) is mutually orthogonal to the focusing direction of the combined cylindrical lens (3), the cylindrical mirror (2) focusing the light beam in a horizontal plane, the combined cylindrical lens (3) focusing the light beam in a vertical plane.

8. A wavelength selective switch according to any one of claims 1-7, wherein the grating (4) is a blazed, phase or prismatic grating.

9. A wavelength selective switch according to any one of claims 1-7, wherein the optical switching engine (5) employs an LCOS chip or a MEMS chip.

10. An intelligent optical network device comprising the wavelength selective switch of any one of claims 1-9.