Alps Electric Co Ltd announced that it has developed an aspherical glass lens compatible with wide-angle laser diodes for optical communications.
The lens, the "FLGS3," has an optical coupling efficiency (indicator of light transmission efficiency) of 73%, which was improved from 68%. Its dimensions are 1.0 x 1.0 x 0.8mm, which Alps claims are the smallest in the industry. The company started volume production at its Nagaoka Plant (Nagaoka City, Niigata Prefecture, Japan) in July 2011, and it plans to produce 100,000 units per month in December 2012.
Glass lenses are mainly used in transceiver modules for optical communications for undersea cables and base stations. Especially, aspherical glass lenses are suited for transmitting optical signals in optical fibers with low loss. Recently, glass lenses began to be employed for palm-sized projectors, and Apls expects that the new lens will be used in the consumer market.
Despite its industry's smallest size, the FLGS3 has an effective numerical aperture of 0.65 x 0.13 while that of Apls' existing product is 0.5 x 0.1. As a result, the optical coupling efficiency was improved to 73%.
The improvement of optical coupling efficiency enables to reduce light loss and light input necessary for producing a certain level of light output. Therefore, it becomes possible to reduce power consumption and heat generation. Also, as for use in projectors, the new lens is suited for high-brightness types.
On the surface of the new glass lens, a dielectric multilayer film is vapor-deposited by sputtering. By changing the film, it is possible to support not only a standard wavelength band for optical communications (1,260 to 1,625nm) but also a visible wavelength band for small-sized projectors (400 to 600nm).