Scully, Scott, Murphy & Presser
Semiconductor laser with a rewritable wavelength stabilizer
A semiconductor laser with a rewritable wavelength stabilizer which comprises a laser mirror made of a grating written into a photorefractive material, in which the oscillation wavelength of the laser diode is determined by the period of the grating. This allows the refractive index of the grating to be changed by illuminating the photorefractive material after cooling thereof to a temperature at which most of the doped impurities form DX centers. The grating can be erased by heating the photorefractive material to a temperature at which most DX centers are ionized, which erases the grating. Thereafter the photorefractive material is cooled again to a temperature at which most impurities become DX centers, and a new grating can be written in the photorefractive material. The wavelength of the semiconductor laser can be changed repeatedly by erasing and rewriting the grating therein. The laser diode is maintained and operated at a low temperature to maintain the grating semi-permanently therein while the temperature remains low.
NEC Corporation
H H G
H01S H01S G02B
inventional additional additional
Hirohito Richard A.
Yamada Linke