Patent ID: 6771681
Filing Date: 2004-08-03
Classification: H01S

Abstract:
A distributed feedback semiconductor laser comprising:a semiconductor substrate; first and second clad layers formed on the semiconductor substrate, said first and second clad layers having predetermined refractive indexes; a guide layer arranged between the first and second clad layers, for propagating light; an oscillating act active layer arranged between the second clad layer and the guide layer, for oscillating light at a predetermined wavelength; and an amplifying active layer between the second clad layer and the guide layer, for amplifying the light with a predetermined gain; wherein a laser oscillation section comprises a predetermined portion of the distributed feedback semiconductor laser including the oscillating active layer, and a laser amplification section comprises a remaining portion of the distributed feedback semiconductor laser including the amplifying active layers; wherein first gratings are formed on a lower surface of the guide layer in the laser oscillation section; wherein second gratings are formed on a lower surface of the guide layer in the laser amplification section; and wherein a period of the first gratings is longer than a period of the second gratings and a gain wave length of the amplifying active layer is approximate to a distributed feedback wavelength of the first gratings.