Patent highlights

22 Aug 2003

The pick of this week’s patent applications including an improved drive circuit for semiconductor lasers.

•  Title: Optically powered resonant integrated microstructure pressure sensor
Applicant: Honeywell International Inc, US
International Application Number: WO 03/067208
Honeywell has designed a pressure sensor that works by monitoring the changes in a light beam inside a tiny Fabry Perot cavity. The sensor is made of a polysilicon shell that is bonded to a flat substrate featuring a photodiode and a fluorescent compound such as erbium. A mechanical beam is bonded to the inner surface of the shell and the shell, the beam and the substrate form a Fabry-Perot cavity. Light is injected into and removed from the cavity via an optical fiber. Pressure on the shell changes the position of the beam and modulates the light. Electronics analyses the modulated light to determine the pressure surrounding the sensor.

•  Title: Semiconductor laser drive circuit
Applicant: Sony Corporation, Japan
International Application Number: WO 03/067584
Sony has come up with a laser drive circuit that enables the generation of short light pulses at a high transfer rate. The Japanese electronics giant claims that the circuit not only reduces the number of wire connections that are needed but also eliminates timing shifts in the emitted pulse that are due to a difference in wire length.

•  Title: Laser device comprising a quantum cascade laser
Applicant: Fraunhofer Gesellschaft zur Forderung der Angewandten Forschung, Germany
International Application Number: WO 03/067720
Pulsed quantum cascade lasers that operate at frequencies of up to 100 kKz are described in patent application WO 03/067720. The invention consists of a quantum cascade laser, a pulse generator and a heat dissipation device. According to the application, a special control method enables a partially coherent LED-type light emission.

•  Title: Multimode optical fiber, fiber laser amplifier and fiber laser oscillator
Applicant: Mitsubishi Cable Industries, Japan
International Application Number: WO 03/067723
Mitsubishi is attempting to patent a design of doped multimode optical fiber for making fiber lasers and amplifiers. The design consists of a core doped with a suitable gain medium that is surrounded by an undoped ring, a doped signal-absorbing region and a cladding.

Author
Oliver Graydon is editor of Optics.org and Opto & Laser Europe magazine.