Optical processing

• US 10,642,126 B2
• Filed: 01/03/2019
• Issued: 05/05/2020
• Est. Priority Date: 09/03/2001
• Status: Expired due to Term

• Current Assignee: Thomas Swan & Company Limited (Aixtron AG)
• Original Assignee: Thomas Swan & Company Limited (Aixtron AG)
• Inventors: Holmes, Melanie
• Primary Examiner(s): Dinh, Jack
• Application Number:
  US16/239,286
• Publication Number:
  US 20190219889A1
• Time in Patent Office: 488 Days
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G02B 26/0808 by means of one or more diffracting elements
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 5/32 Holograms used as optical elements
• CPC Class Codes: G02B 6/266 the optical element being an attenuator
• CPC Class Codes: G02B 6/29311 Diffractive element operating in transmission
• CPC Class Codes: G02B 6/29314 by moving or modifying the diffractive element, e.g. deforming
• CPC Class Codes: G02B 6/2938 for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
• CPC Class Codes: G02B 6/29391 Power equalisation of different channels, e.g. power flattening
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/3534 the optical element being diffractive, i.e. a grating
• CPC Class Codes: G02B 6/3548 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02F 1/1326 Liquid crystal optical waveguides or liquid crystal cells specially adapted for gating or modulating between optical waveguides
• CPC Class Codes: G02F 1/13342 Holographic polymer dispersed liquid crystals
• CPC Class Codes: G02F 1/1335 Structural association of cells with optical devices, e.g. polarisers or reflectors
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection
• CPC Class Codes: G02F 1/291 Two-dimensional analogue deflection
• CPC Class Codes: G02F 1/31 Digital deflection, i.e. optical switchingG02F1/33 takes precedence
• CPC Class Codes: G02F 1/3132 of directional coupler type
• CPC Class Codes: G02F 2201/30 : grating
• CPC Class Codes: G02F 2201/34 : reflector
• CPC Class Codes: G02F 2203/12 : spatial light modulator
• CPC Class Codes: G02F 2203/28 : focussing or defocussing
• CPC Class Codes: G02F 2203/50 : Phase-only modulation
• CPC Class Codes: G03H 1/0005 : Adaptation of holography to specific applications holographic optical element G02B5/32; holographic scanner G02B26/106; recognition using holographic mask G06V10/88; holographic memories G11B7/0065, G11C13/042
• CPC Class Codes: G03H 1/02 : Details of features involved during the holographic process; Replication of holograms without interference recording
• CPC Class Codes: G03H 1/04 : Processes or apparatus for producing holograms G03H1/26 takes precedence
• CPC Class Codes: G03H 1/08 : Synthesising holograms, i.e. holograms synthesized from objects or objects from hologramsusing electric digital computers G06F; G06T
• CPC Class Codes: G03H 1/0866 : Digital holographic imaging, i.e. synthesizing holobjects from holograms
• CPC Class Codes: G03H 1/0891 : Processes or apparatus adapted to convert digital holographic data into a hologram G03H1/2294 takes precedence
• CPC Class Codes: G03H 1/2286 : Particular reconstruction light G03H1/24 takes precedence; Beam properties
• CPC Class Codes: G03H 1/2294 : Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 1/26 : Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
• CPC Class Codes: G03H 2001/0224 : Active addressable light modulator, i.e. Spatial Light Modulator [SLM] corresponding details, see subgroups of G03H2225/00
• CPC Class Codes: G03H 2001/0491 : by monitoring the hologram formation, e.g. via a feed-back loop
• CPC Class Codes: G03H 2001/261 : in optical contact
• CPC Class Codes: G03H 2001/264 : One hologram being a HOE
• CPC Class Codes: G03H 2222/13 : Multi-wavelengths wave with discontinuous wavelength ranges G03H2222/18 takes precedence
• CPC Class Codes: G03H 2222/32 : Unpolarised light
• CPC Class Codes: G03H 2223/23 : Diffractive element
• CPC Class Codes: G03H 2225/32 : Phase only
• CPC Class Codes: G03H 2225/52 : Reflective modulator
• CPC Class Codes: G03H 2225/60 : Multiple SLMs
• CPC Class Codes: G03H 2226/02 : Computing or processing means, e.g. digital signal processor [DSP]
• CPC Class Codes: H04J 14/021 : Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0212 : using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0213 : Groups of channels or wave bands arrangements
• CPC Class Codes: H04J 14/0217 : Multi-degree architectures, e.g. having a connection degree greater than two
• CPC Class Codes: H04J 14/0219 : Modular or upgradable architectures
• CPC Class Codes: H04J 14/022 : For interconnection of WDM optical networks
• CPC Class Codes: H04J 14/08 : Time-division multiplex systems
• CPC Class Codes: H04Q 11/0005 : Switch and router aspects
• CPC Class Codes: H04Q 2011/0016 : using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0028 : using holograms
• CPC Class Codes: H04Q 2011/0039 : Electrical control

Abstract

A modular routing node includes a single input port and a plurality of output ports. The modular routing node is arranged to produce a plurality of different deflections and uses small adjustments to compensate for wavelength differences and alignment tolerances in an optical system. An optical device is arranged to receive a multiplex of many optical signals at different wavelengths, to separate the optical signals into at least two groups, and to process at least one of the groups adaptively.

Claims

1. An optical routing module having at least one input and at least two outputs and operable to select between the outputs, the module comprising:

a reflective Spatial Light Modulator (SLM) having a two-dimensional array of controllable elements, a dispersion device, an optical device, and circuitry constructed and arranged to control the controllable elements of the SLM to determine what is output, wherein;

the dispersion device is disposed to receive light beams of different centre wavelengths from said at least one input;

the optical device is disposed to receive angularly dispersed light beams from the dispersion device, to direct the light beams as input light beams to respective different two-dimensional groups of controllable elements of the SLM and to spatially distribute the light beams from the dispersion device by wavelength both across the SLM and within each of the two-dimensional groups, thereby to form light beams having spatially separated centre wavelengths at the SLM;

the SLM is disposed to receive one or more input light beams having spatially separated centre wavelengths from the optical device and to form one or more emergent reflected output light beams;

the SLM is operable to steer the emergent reflected output light beams away from the input light beams; and

the optical device and dispersion element are further disposed such that all wavelengths selected for routing to an output are combined into a respective common beam.

2. The optical routing module of claim 1, wherein the optical device is a focusing element configured to focus light in at least one dimension.

3. The optical routing module of claim 2, wherein during operation, the light beams having spatially separated centre wavelengths formed at the SLM are each focused along a wavelength dispersion dimension by the optical device.

4. The optical routing module of claim 3, wherein the optical device comprises a lens.

5. The optical routing module of claim 3, wherein the optical device comprises a curved mirror.

6. The optical routing module of claim 1, wherein the dispersion device comprises at least one reflective device and at least one transmissive device.

7. The optical routing module of claim 1, wherein the dispersion device comprises at least one of:

a blazed grating;

a holographic grating, an etched grating, an arrayed waveguide grating and a prism.

8. The optical routing module of claim 1, wherein the SLM incorporates a wave-plate whereby the SLM is substantially polarisation-independent.

9. The optical routing module of claim 1, wherein the different two-dimensional groups of controllable elements on the SLM are capable of independently deflecting incident light.

10. The optical routing module of claim 9, wherein the controllable elements of the SLM comprise phase-modulating elements.

11. The optical routing module of claim 10, wherein the SLM is a Liquid Crystal on Silicon Spatial Light Modulator (LCOS SLM).

12. The optical routing module of claim 1, wherein the dispersion device comprises a first and a second dispersion element.

13. The optical routing module of claim 1, further comprising a control device operable to select, from stored control data, control data for each group of controllable elements to generate from the respective selected control data a respective hologram at each group of controllable elements, and to vary the selection of control data, whereby upon illumination of said groups by respective light beams, respective emergent light beams from the groups are controllable independently of each other.

14. The optical routing module of claim 1, wherein the controllable elements comprise phase modulating elements, and further comprising a control device operable to select, from stored control data, control data for each group of phase-modulating elements to generate from the respective selected control data a respective hologram at each group of phase-modulating elements, wherein a transmission spectrum at an output from the routing module is created by the holograms at two or more adjacent groups of phase-modulating elements, the respective holograms on the adjacent groups are routing in the same direction, and the control data is selected to create a flat passband for the transmission spectrum.

15. The optical routing module of claim 1, wherein the controllable elements comprise phase modulating elements, and further comprising a control device operable to select, from stored control data, control data for each group of phase-modulating elements to generate from the respective selected control data a respective hologram at each group of phase-modulating elements, wherein a transmission spectrum at an output from the routing module is created by the holograms at two or more adjacent groups of phase-modulating elements, the respective holograms on the adjacent groups are routing in the same direction, and the control data is selected to reduce effects created by the edges of the adjacent holograms.

16. The optical routing module of claim 15 wherein the effects are filtering effects caused by stitching errors.

17. The optical routing module of claim 1, further comprising a control device operable to:

delineate groups of individual controllable elements; and

select, from stored control data, control data for each group of controllable elements to generate from the respective selected control data a respective hologram at each group of controllable elements, whereby wavelength channels are passed from the at least one input to the two or more outputs.

18. The optical routing module of claim 17, wherein the control device is further operable to vary at least one of the delineation of the groups and the selection of control data whereby the width of one or more channel pass bands is varied.

19. The optical routing module of claim 17, wherein the control device is further operable to vary at least one of the delineation of the groups and the selection of control data whereby the centre wavelength of one or more channel pass bands is varied.

20. The optical routing module of claim 17, wherein the control device is configurable to set a transmission spectrum between adjacent channels at an output.

21. The optical routing module of claim 17, wherein the control device is further configurable to select the groups of controllable elements so that groups corresponding to the adjacent wavelength channels are spaced from one another on the SLM.

22. The optical routing module of claim 17, wherein the control device is further configurable to cause the controllable elements in the space between the groups corresponding to the adjacent wavelength channels to form a guard band.

23. The optical module of claim 22, further wherein the control device is further configurable to cause the controllable elements forming the guard band to deflect incident light away from the at least two outputs.

24. The optical routing module of claim 1, further comprising a control device operable to:

delineate groups of individual controllable elements;

select, from stored control data, control data for each group of controllable elements to generate from the respective selected control data a respective hologram at each group of controllable elements; and

vary at least one of the delineation of the groups and the selection of control data, whereby upon illumination of said groups by respective light beams, respective emergent light beams from the groups are controllable independently of each other.

25. The optical routing module of claim 1, further comprising a control device configurable to select the groups so that at least one group has a size different from that of another group.

26. The optical routing module of claim 1, further comprising a control device configurable to select the groups so that at least one group has a shape different from that of another group.

27. The optical routing module of claim 1, further comprising a control device configurable to change one or more of sizes, shapes, and positions of the groups in response to a request from a network management system for one of a change in central wavelength and a change in a bandwidth and a change in both of one or more of the wavelength channels.