AOI gets in tune with four new US patents
Applied Optoelectronics Inc. (AOI) has been issued with four new US patents covering tunable laser technology.
The latest awards bring the total number of patents that AOI owns in the tunable laser field to ten.
"The patents are a significant part of a broad portfolio of technologies developed to address shortcomings in existing diode laser technology," said Wen-Yen Hwang, the company s VP of engineering.
AOI added that it expects to start offering commercial products based on the extensive intellectual property that it now owns "in the next few quarters".
The Texas-based firm, which manufactures components at its headquarters near Houston, has previously worked on a number of exotic devices, including quantum cascade lasers (QCLs).
However, AOI now appears to be focused firmly on fiber-optic communications and stopped making QCLs last year (see related story). The company is confident of a recovery in fiber-optics, citing a "revitalized need for advanced optical components" as growth returns to the sector.
Three of the recently-awarded patents are focused on "multiple reflectivity band reflector (MRBR)" technology. For example, patent number 6,788,466 details an MRBR consisting of a stack of dielectric layers.
These layers are arranged to create a reflectivity profile in one of the laser s mirrors. Two wavelength bands are set to have a reflectivity above the lasing threshold, while a third wavelength range (in between the other two) has a reflectivity below the lasing threshold.
The gain spectrum of the laser can then be adjusted to select either of the two wavelength bands with high reflectivity and tuned across the range. AOI suggests that the laser could be either a monolithic VCSEL or a two-section external-cavity VECSEL, incorporating the MRBR as one of the cavity mirrors.
