Strained layer quantum well semiconductor optical amplifiers : polarization insensitive amplification

Abstract : Optical amplifiers are important devices for future optical fiber transmission and other photonic technologies. Semiconductor laser amplifiers are attractive candidates for these applications because of theirs high gain, compactness, possibility of integration with light source and so on. In comparison with fiber amplifiers such as Er+-doped fibers, the semiconductor laser amplifiers have a disadvantage which is large difference between TE and TM gain. Therefore, to control the TE/TM mode gain is a key item in the development of semiconductor amplifiers. For polarization insensitive amplification in the semiconductor laser amplifier, several approaches have been proposed by geometric designing of active layers. 1-3 In this paper, we describe an approach to the polarization insensitive optical amplifier in which active layer consisted of GaInAsP multiple quantum well structures with biaxially tensile strains within well layers. A group has reported a strained layer quantum well amplifier with tensed barriers. 4 In this work, we investigated the effects of biaxially tensile strain on amplification in the quaternary strained quantum well amplifiers. The polarization insensitive amplification was successfully demonstrated.