Mems device having multiple DWDM filters

• US 20020044721A1
• Filed: 06/08/2001
• Published: 04/18/2002
• Est. Priority Date: 06/09/2000
• Status: Abandoned Application

• Current Assignee: LNL Technologies, Inc.
• Original Assignee: LNL Technologies, Inc.
• Inventors: Bjorklund, Gary C.
• Application Number:
  US09/877,692
• Publication Number:
  US 20020044721A1
• Time in Patent Office: Days
• US Class Current: 385/18
• CPC Class Codes: G02B 6/29361 Interference filters, e.g. multilayer coatings, thin film filters, dichroic splitters or mirrors based on multilayers, WDM filters
• CPC Class Codes: G02B 6/29395 configurable, e.g. tunable or reconfigurable switching G02B6/35
• CPC Class Codes: G02B 6/3532 the optical element being a wavelength independent filter or having spatially dependent transmission properties, e.g. neutral filter or neutral density wedge substrate with plurality of density filters
• CPC Class Codes: G02B 6/355 1x2 switch, i.e. one input and a selectable single output of two possible outputs
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3576 Temperature or heat actuation thermal forces controlling reflecting elements in general G02B26/0866; thermo-optic devices G02F1/0147
• CPC Class Codes: G02B 6/3578 Piezoelectric force piezoelectric forces controlling reflecting elements in general G02B26/0858; piezo-optic devices G02F1/0131
• CPC Class Codes: G02B 6/3596 With planar waveguide arrangement, i.e. in a substrate, regardless if actuating mechanism is outside the substrate

Abstract

An optical signal processing method and a device which can serve as a signal multiplexer or demultiplexer can be tuned in discrete increments. This device has a movable filter assembly having a number of filters, with each filter having a surface which reflects a particular wavelength of light and passes other wavelengths of light. This defines two wavelength-dependent signal paths. Light reflecting from a reflective surface of the filter passes along one signal path which includes an input waveguide and a first output waveguide. Light transmitted through the filter travels along another signal path which includes the input waveguide and a second output waveguide. The filter can be contained in a trench separating the input and second output waveguides, and can be moved in the trench to alter the optical properties of the two signal paths.

Claims

1. An optical signal processing device, comprising:

a first waveguide defining a first waveguide optical path;

a second waveguide defining a second waveguide optical path generally coaxial with the first waveguide optical path;

a third waveguide defining a third waveguide optical path that is oriented with respect to the first waveguide optical path at a predetermined angle;

the first, second and third waveguides being arranged around a trench that separates the first waveguide and the second waveguide;

a filter assembly disposed in the trench and having a plurality of filters, each of which has an associated reflective wavelength such that the filter reflects that associated reflective wavelength; and

an actuator connected to the filter assembly for causing the filter assembly to move to position one of the filters between the first and the second waveguides, so that a first optical path for an optical signal having the associated reflective wavelength includes the first waveguide optical path and the third waveguide optical path, and a second optical path for an optical signal not having the associated reflective wavelength includes the first waveguide optical path and the second waveguide optical path.

2. An optical signal processing device according to claim 1, wherein the one of the filters has a reflective surface which reflects light having the associated reflective wavelength and a transparent body through which light having a wavelength other than the associated reflective wavelength can pass.

3. An optical signal processing device according to claim 1, wherein the signal processing device is a multiplexer.

4. An optical signal processing device according to claim 1, wherein the signal processing device is a demultiplexer.

5. An optical signal processing device according to claim 1, wherein an optical signal propagating along the first waveguide comprises a plurality of channel signals, each said channel signal having a wavelength.

6. An optical signal processing device according to claim 5, wherein each channel signal has a unique wavelength.

7. An optical signal processing device according to claim 1, wherein the filters are arranged in a one-dimensional array.

8. An optical signal processing device according to claim 1, wherein the filters are arranged in a two-dimensional array.

9. An optical signal processing device according to claim 1, wherein the filters all have substantially a same thickness.

10. An optical signal processing device according to claim 1, wherein the filters all have different associated reflective wavelengths.

11. An optical signal processing device according to claim 1, further comprising:

a medium disposed in the trench and having an associated index of refraction; and

wherein an associated index of refraction for each of the first, second and third waveguides are approximately the same and are different than the associated index of refraction of the medium, the first and second waveguides and the first and third waveguides being separated from each other by a distance over which an optical signal passing therethrough is not affected by the different indices of refraction of the waveguides and the medium.

12. An optical signal processing device according to claim 5, wherein an optical signal propagating along the first waveguide strikes one of the filters in the filter assembly, so that one of the channel signals is reflected from the filter through the third waveguide and the other channel signals of the optical signal propagate through the second waveguide.

13. An optical signal processing device according to claim 1, wherein an index of refraction of the first, second and third waveguides is approximately the same.

14. An optical signal processing device according to claim 1, wherein the first waveguide has a facet through which an optical signal exits the first waveguide to enter the trench, the second waveguide has a facet through which an optical signal transmitted through the one of the filters between the first and the second waveguides across the trench enters the second waveguide, and the third waveguide has a facet through which an optical signal reflected by the reflective surface and leaving the trench enters the third waveguide.

15. An optical signal processing device according to claim 14, wherein at least one of the first, second and third waveguide facets is angled with respect to the corresponding waveguide'"'"'s optical path.

18. A method according to claim 17, further comprising the step of selecting the channel of the optical signal which is reflected into the first waveguide according to that channels'"'"' associated wavelength

19. A method according to claim 18, wherein the reflecting of the channel of the optical signal having the associated reflective wavelength into the first output waveguide comprises the steps of:

providing a filter assembly comprising at least one reflector, the reflector reflecting light having a particular wavelength and transmitting light not having the particular wavelength; and

positioning the filter in the optical path so that the optical signal strikes the reflector.

16. An optical signal processing device, comprising:

a first waveguide defining a first waveguide optical path;

a second waveguide defining a second waveguide optical path generally coaxial with the first waveguide optical path;

a third waveguide defining a third waveguide optical path that is oriented with respect to the first waveguide optical path at a predetermined angle;

the first, second and third waveguides being arranged around a trench that separates the first waveguide and the second waveguide;

a filter assembly disposed in the trench and having a plurality of filters each of which has an associated reflective wavelength such that the filter reflects that associated reflective wavelength; and

an actuator connected to the filter assembly for causing the filter assembly to move to position one of the filters between the first and the second waveguides, so that an optical signal propagating along the first waveguide and having a wavelength approximately equal to the reflective wavelength of the one of the filters is reflected by the one of the filters into the third waveguide, and an optical signal propagating along the first waveguide having a wavelength not approximately equal to the reflective wavelength of the one of the filters passes through the one of the filters to the second waveguide.

17. A method of processing an optical signal having a plurality of channels, each channel having a wavelength associated therewith, comprising the steps of:

providing a first optical waveguide for guiding the optical signal;

providing a plurality of reflectors, each having an associated reflective wavelength;

providing a first output waveguide; and

providing a second output waveguide, positioning a selected reflector relative to the first optical waveguide such that a selected channel of the optical signal having the associated wavelength is reflected by the reflector into the first output waveguide, and wherein channels not having the associated reflective wavelength pass through the reflector to the second output waveguide.

20. A method of processing an optical signal having a plurality of channels, each channel having a wavelength associated therewith, comprising the steps of

guiding the optical signal along a first optical waveguide defining a first optical path to strike a reflector, the reflector having an associated reflective wavelength;

reflecting a channel of the optical signal having the associated reflective wavelength into a first optical output path defined by a first output waveguide; and

transmitting channels of the optical signal not having the associated reflective wavelength through the reflector into a second optical output path defined by a second output waveguide.