Optical system and method

• US 20030086139A1
• Filed: 08/20/2002
• Published: 05/08/2003
• Est. Priority Date: 08/20/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Wing So, John Ling
• Granted Patent: US 6,842,549 B2
• Time in Patent Office: Days
• US Class Current: 398/87
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 5/203 having holographic or diffractive elements diffraction gratings per se G02B5/18; holographic elements per se G02B5/32; generating the spectrum using diffraction elements G01J3/18
• CPC Class Codes: G02B 6/2706 as bulk elements, i.e. free space arrangements external to a light guide, e.g. polarising beam splitters
• CPC Class Codes: G02B 6/278 Controlling polarisation mode dispersion [PMD], e.g. PMD compensation or emulation PMD minimised transmission systems H04B10/2569
• CPC Class Codes: G02B 6/2793 Controlling polarisation dependent loss, e.g. polarisation insensitivity, reducing the change in polarisation degree of the output light even if the input polarisation state fluctuates
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• CPC Class Codes: G02B 6/29313 characterised by means for controlling the position or direction of light incident to or leaving the diffractive element, e.g. for varying the wavelength response switching G02B6/35
• CPC Class Codes: G02B 6/29389 Bandpass filtering, e.g. 1x1 device rejecting or passing certain wavelengths G02B6/2938 takes precedence
• CPC Class Codes: G02B 6/29391 Power equalisation of different channels, e.g. power flattening
• CPC Class Codes: G02B 6/29394 Compensating wavelength dispersion G02B6/29376 takes precedence; dispersion compensated optical transmission systems H04B10/2507
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/3588 of the processed beams, i.e. controlling during switching of orientation, alignment, or beam propagation properties such as intensity, size or shape
• CPC Class Codes: H04B 10/2941 using an equalising unit, e.g. a filter H04B10/296 takes precedence

Abstract

Adaptive dynamic optical filters with wavelength spreading onto a micromirror array and re-configurable attenuation according to measured intensity as a function of wavelength.

Claims

1. A dynamic optical filter, comprising:

(a) an input wavelength spreader;

(b) an array of micromirrors positioned to reflect radiation from said wavelength spreader; and

(c) an output wavelength combiner positioned to received radiation reflected from said micromirrors;

(d) wherein said micromirrors may to adjusted to vary the portion of radiation within a wavelength band reflected towards said output wavelength combiner.

2. The filter of claim 1, wherein:

said spreader and said combiner comprise a grating.

3. The filter of claim 1, wherein:

said input spreader is coupled to an input optical fiber; and

said output combiner is coupled to an output optical fiber.

4. The filter of claim 3, wherein:

said input optical fiber and said output optical fiber are the same optical fiber and separated from said spreader and said combiner by an optical circulator.

5. The filter of claim 1, wherein:

said input spreader is coupled to a plurality of input optical fibers;

said output combiner is coupled to a plurality of output optical fibers; and

wherein radiation from each of said input optical fibers impinges on a corresponding area of said micromirror array.

6. The filter of claim 1, wherein:

said spreader spreads adjacent wavelength bands to overlapping areas on said micromirror array.

7. The filter of claim 1, wherein:

said spreader spreads adjacent wavelength bands to non-overlapping areas on said micromirror array.

8. The filter of claim 1, wherein:

said spreader spreads a wavelength bands to an oblong area on said micromirror array.

10. An adaptive dynamic optical filter, comprising:

(a) an input wavelength spreader;

(b) an array of micromirrors positioned to reflect radiation from said wavelength spreader;

(c) an output wavelength combiner positioned to received radiation reflected from said micromirrors; and

(d) feedback control with input coupled to said output combiner and said output coupled to said array of micromirrors;

(e) wherein said micromirrors may to adjusted to vary the portion of radiation within a wavelength band reflected towards said output wavelength combiner.

11. The filter of claim 10, wherein:

(a) said feedback control monitors the amplitude as a function of wavelength.

12. The filter of claim 10, wherein:

(a) said feedback control monitors the relative phase as a function of wavelength.

13. The filter of claim 10, wherein:

(a) said feedback control monitors the relative group velocity as a function of wavelength.

14. A method of adaptive optical filter control, comprising:

(a) monitoring relative intensity as a function of wavelength for a plurality of wavelengths; and

(b) adjusting an optical filter intensity response in each of said plurality of wavelengths according to a weighted error measurement.