Reflecting wedge optical wavelength multiplexer/demultiplexer

• US 20040202414A1
• Filed: 04/14/2003
• Published: 10/14/2004
• Est. Priority Date: 04/14/2003
• Status: Active Grant

• Current Assignee: Agilent Technologies, Inc.
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Fong, Arthur, Wong, Marvin Glenn
• Granted Patent: US 6,956,990 B2
• Time in Patent Office: Days
• US Class Current: 385/22
• 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 6/3502 involving direct waveguide displacement, e.g. cantilever type waveguide displacement involving waveguide bending, or displacing an interposed waveguide between stationary waveguides
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• 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 6/3582 Housing means or package or arranging details of the switching elements, e.g. for thermal isolation

Abstract

A method and apparatus for multiplexing and demultiplexing optical signals. The apparatus includes first and second optical waveguides coupled via an optical coupler. The optical coupler has a coupling waveguide and an optical switching wedge attached to a piezoelectric actuator. In operation, first and second optical signals are received by the first and second optical waveguides, respectively. If the signals are to be combined, the optical switching wedge is moved to a first position where it is optically coupled to the first optical waveguide. The first optical signal is then transmitted, via the coupling waveguide, to the second optical waveguide, where it is combined with the second optical signal. If the signals are not to be combined, the optical switching wedge is moved to a second position where it is optically uncoupled from the first optical waveguide.

Claims

1. An optical multiplexer/demultiplexer, comprising:

a first optical waveguide operable to receive a first optical signal;

a second optical waveguide; and

an optical coupler operable to couple the first optical signal from the first optical waveguide to the second optical waveguide, the optical coupler comprising;

an optical switching wedge;

a coupling waveguide adapted to transmit light from the optical switching wedge to the second optical waveguide; and

a piezoelectric actuator operable to move the optical switching wedge between a first position, in which the optical switching wedge is optically coupled to the first optical waveguide, and a second position, in which the optical switching wedge is optically uncoupled from the first optical waveguide.

2. An optical multiplexer/demultiplexer in accordance with claim 1, further comprising:

a plurality of first optical waveguides;

a plurality of second optical waveguides; and

a plurality of optical couplers, each operable to couple a first optical waveguide of the plurality of first optical waveguides to a second optical waveguide of the plurality of second optical waveguides.

3. An optical multiplexer/demultiplexer in accordance with claim 1, wherein the piezoelectric actuator is operable to deform in one of a bending mode, an extensional mode and a shear mode.

4. An optical multiplexer/demultiplexer in accordance with claim 1, wherein the second optical waveguide is operable to receive a second optical signal, and wherein the optical coupler is operable to combine the first optical signal with the second optical signal.

5. An optical multiplexer/demultiplexer in accordance with claim 1, wherein a face of the optical switching wedge and an end of the coupling waveguide have anti-reflection coatings to facilitate optical coupling between the optical switching wedge and the coupling waveguide without a need for physical contact.

6. An optical multiplexer/demultiplexer in accordance with claim 1, wherein a face of the optical switching wedge that contacts the first optical waveguide has an index matching coating to facilitate light transmission between the first optical waveguide and the optical switching wedge.

7. An optical multiplexer/demultiplexer in accordance with claim 1, wherein a face of the optical switching wedge that contacts the first optical waveguide incorporates a band-pass optical filter, whereby the optical coupler is operable to transmit light of specified wavelengths between the first optical waveguide and the second optical waveguide.

8. An optical multiplexer/demultiplexer in accordance with claim 1, wherein the second optical waveguide is positioned above the first optical waveguide and oriented in a different direction to the first optical waveguide.

9. An optical multiplexer/demultiplexer in accordance with claim 8, wherein the optical switching wedge is positioned above the first optical waveguide and is moveable in a vertical direction.

10. A method of manufacture for an optical multiplexer/demultiplexer, comprising;

forming a plurality of first grooves in a lower substrate;

inserting optical waveguide material in each of the plurality of first grooves to form a plurality of first optical waveguides;

forming an upper substrate on top of the lower substrate;

forming a plurality of second grooves in a upper substrate;

inserting optical waveguide material in each of the plurality of second grooves to form a plurality of second optical waveguides and a plurality of coupling waveguides, each coupling waveguide being optically coupled to a second optical waveguide;

attaching a plurality of optical couplers to a top layer; and

fixing the top layer above the lower substrate and the upper substrate so that the plurality of optical couplers are aligned to couple light from the plurality of first optical waveguides to the plurality of coupling waveguides.

11. A method in accordance with claim 10, further comprising:

depositing a plurality of electrical traces on the top layer to provide electrical connections to the plurality of optical couplers.

12. A method in accordance with claim 10, further comprising:

assembling an optical coupler of the plurality of optical couplers by attaching an optical switching wedge to a piezoelectric actuator via a spacer and attaching the piezoelectric actuator to the top layer via one or more rigid standoffs.

13. A method in accordance with claim 10, wherein the forming a plurality of first grooves in a lower substrate comprises laser ablation of the lower substrate.

14. A method in accordance with claim 10, wherein the forming a plurality of first grooves in a lower substrate comprises etching of the lower substrate.

15. A method for selectively combining a first optical signal and a second optical signal in an optical multiplexer/demultiplexer, the method comprising:

receiving an input optical signal in a first optical waveguide, the input optical signal containing the first optical signal;

receiving the second optical signal in a second optical waveguide;

if the signals are to be combined;

moving an optical switching wedge to a first position where it is optically coupled to the first optical signal in the first optical waveguide and transmits the first optical signal to a coupling waveguide;

transmitting the first optical signal along the coupling waveguide to the second optical waveguide; and

combining the first optical signal with the second optical signal; and

if the signals are not to be combined;

moving the optical switching wedge to a second position where it is optically uncoupled from the first optical waveguide.

16. A method in accordance with claim 15, wherein moving the optical switching wedge comprising energizing and de-energizing a piezoelectric actuator by application of an electrical voltage.

17. A method in accordance with claim 15, wherein the input optical signal comprises a plurality of component optical signals having different wavelengths and wherein the first optical signal comprises a subset of the plurality of component optical signals.

18. A method in accordance with claim 15, wherein the second optical signal comprises a plurality of component optical signals having different wavelengths and wherein the input optical signal comprises a subset of the plurality of component optical signals.