Bookham Technology Limited

Other

Arnold Peter Harpin

Andrew George Rickman

Robin Jeremy Morris

Stephen James Crampton

Mehdi Asghari

John Paul Drake

James Stuart McKenzie

Ralf-Dieter Pechstedt

Stephen Gorton

An integrated optical circuit for use in a fibre optic gyroscope which senses rotation rates by determining a phase shift due to the Sagnac Effect between light beams travelling around an optical fibre sensing loop (4) in opposite directions, the circuit being provided on a silicon-on-insulator chip comprising a layer of silicon separated from a substrate by an insulating layer, the circuit comprising: rib waveguides (11) formed in the silicon layer for receiving light from a light source (2) and transmitting light to a light detector (3), fibre optic connectors (9) in the form of grooves etched in the silicon layer for receiving the respective ends of the optical fibre sensing loop (4); rib waveguides (11) formed in the silicon layer for transmitting light to and from said fibre optic connectors (9) so as to direct light beams in opposite directions around the sensing loop (4) and receive light beams returning therefrom, phase determining means and (13,17,31) integrated in silicon layer for determining a phase shift between the light beams returning from the sensing loop (4).

Integrated optical circuit

The device is formed on a silicon-on-insulator chip (which comprises a layer of silicon (1) separated from a substrate (3) by an insulator layer (2)) and comprises an integrated waveguide (4) formed in the silicon layer (1) and a reflective facet (6) formed in a recess in the silicon layer (1). The facet (6) is positioned to redirect light in a desired direction. The waveguide (4) and facet (6) are both formed in the silicon layer (1) so their positions can be defined by the same lithographic steps so they are automatically aligned with each other.

Device for re-directing light from optical waveguide

A tapered rib waveguide tapering from a large, multi-mode optical waveguide to a smaller, single-mode optical waveguide, the tapered rib waveguide comprising two portions (4,5) formed of the same material: a lower portion (4) which tapers laterally from the large waveguide to the smaller waveguide and an upper portion (5) formed on the lower portion (4), which tapers to a point (or other form of termination), the dimensions of the two portions (4,5) being such that substantially all of a fundamental mode propagated in the large multi-mode waveguide is coupled to the smaller, single-mode waveguide.

Tapered rib waveguide

A silicon-on-insulator chip has a location recess formed therein for receiving a laser diode. The location recess includes two non-parallel location surfaces adapted to abut against two reference surfaces formed on the laser diode. The abutment of the location surfaces against the reference surfaces enables a laser emission area of the laser diode to be accurately aligned with a rib waveguide formed on the silicon-on-insulator substrate.

Assembly of an optical component and an optical waveguide

The device comprises a layer of silicon separated from a substrate by a layer of insulating material. A rib having an upper surface and two side surfaces is formed in the layer of silicon to provide a waveguide for the transmission of optical signals. A lateral doped junction is formed between the side surfaces of the rib such that an electrical signal can be applied across the junction to control the density of charge carriers across a substantial part of the cross-sectional area of the rib thereby actively altering the effective refractive index of the waveguide.

Electro-optic device

A connection between an integrated optical waveguide and an optical fibre has a layer of silicon in which a rib waveguide is formed separated from a substrate by a layer of silicon dioxide. A V-groove is formed in the substrate for receiving an optical fibre, and the V-groove is arranged to align the optical fibre at a predetermined angle with respect to the waveguide. The rib waveguide and the underlying layer of silicon dioxide are formed to overhang the end of the V-groove so that the end of the waveguide is in close proximity with the end of an optical fibre positioned in the V-groove. A method of forming a connection, in which the V-groove is etched using a material which etches the substrate material as opposed to the layer of silicon dioxide, is also disclosed. Finally, a method of connecting an integrated optical waveguide to an optical fibre using a connection as described above is disclosed.

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Oxford, United Kingdom

Arnold Peter Harpin