Optical devices and methods of fabrication thereof

• US 6,778,746 B2
• Filed: 03/11/2003
• Issued: 08/17/2004
• Est. Priority Date: 05/16/1997
• Status: Expired due to Term

• Current Assignee: Nanogan Limited (IQE, PLC)
• Original Assignee: BTG International Limited (Boston Scientific Corporation)
• Inventors: Parker, Gregory Jason, Charlton, Martin David Brian
• Primary Examiner(s): Healy, Brian
• Application Number:
  US10/384,551
• Publication Number:
  US 20030174940A1
• Time in Patent Office: 525 Days
• Field of Search: 385/122, 385/24, 385/15, 385/129, 385/130, 385/37, 385/141, 385/27, 385/28, 398/81, 398/87
• US Class Current: 385/122
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01N 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B
• CPC Class Codes: G01N 21/774 the reagent being on a grating or periodic structure
• CPC Class Codes: G02B 2006/12164 Multiplexing; Demultiplexing
• CPC Class Codes: G02B 6/12014 characterised by the wavefront splitting or combining section, e.g. grooves or optical elements in a slab waveguide
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/2813 based on multimode interference effect, i.e. self-imaging
• CPC Class Codes: G02B 6/2861 using fibre optic delay lines and optical elements associated with them, e.g. for use in signal processing, e.g. filtering delay lines in general H03H, H01P9/00; optical computing devices G06E
• CPC Class Codes: G02F 1/365 in an optical waveguide structure G02F1/377, G02F1/395 take precedence
• CPC Class Codes: H01S 3/063 Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength waveguide gas lasers H01S3/0315
• CPC Class Codes: H01S 3/0635 provided with a periodic structure, e.g. using distributed feed-back, grating couplers controlling, e.g. modulating distributed feed-back lasers H01S3/102

Abstract

An optical device includes a waveguide bounded by a region containing a photonic band gap the properties of which determined the transfer characteristic of the waveguide. Such a device may serve as a component of, for example a wavelength division multiplexer, a monochromatic laser or a chemical sensor. It may serve as an optical bus for an electronic component such as a microprocessor.

These devices are particularly suitable for incorporation in optical and opto-electronic integrated circuits as they permit the fabrication of waveguides having right-angle bends with a radius of the order of 2 μm.

Claims

1. An optical device comprising a region having a planar waveguide structure having a 2-dimensional patterned array that gives rise to a photonic band structure, the photonic band structure region being adapted so that an optical signal of a predetermined wavelength incident on the optical device is slowed to a predetermined group velocity within the photonic band structure region.

2. An optical device according to claim 1, further comprising an input wave guide and a boundary region between the input wave guide and the photonic band structure region, the boundary region being adapted so as to ensure that the optical signal is coupled into a particular mode.

3. An optical device according to claim 1, wherein the photonic band structure region comprises a periodic lattice structure.

4. An optical device according to claim 3, wherein the lattice structure comprises a first region having a first dielectric constant and a two dimensional planar array of second regions having a second dielectric constant, the properties of the photonic band structure region, and hence the group velocity of the optical signal, being dependent on the configuration of the array of second regions.

5. An optical delay line including an optical device according to claim 1.

6. An optical memory element including an optical device according to claim 1.

7. A method of delaying an optical signal comprising the step of coupling the optical signal into a particular mode in a photonic band structure region such that the group velocity of the optical signal within the photonic band structure region is reduced to a predetermined group velocity.

8. A method according to claim 7, further comprising the step of selecting the angle of propagation of the optical signal in the photonic band structure region so as to alter the speed of propagation of the signal within the photonic band structure region.

9. A method according to claim 7, wherein the photonic band structure region is adapted such that the group velocity of the photon beam within the photonic bandgap region is zero.

10. An optical device supporting an optical path, including:

an optical input;

an optical output; and

an optical filter comprising a planar waveguide structure having a 2-dimensional patterned array that gives rise to a photonic band structure having at least one dispersion band, the optical filter being positioned within the optical path such that light travelling from the optical input to the optical output is coupled into a dispersion mode on a dispersion band and so propagates through the patterned array, the light propagating through the patterned array being slowed to a group velocity which is dependent upon its wavelength.