30 the si layer 31 is separated from the bulk of the wafer 30 by a buried oxide layer 32 the passive grating 35 is made in the si layer 31 the passive grating 35 is arranged adjacent an in plane si waveguide 36 so as to allow coupling of light from the laser structure to the waveguide 36 the active material included in the active region 12 may be in the form of quantum wells in this case in order to prevent surface recombination the active region 12 may be a bh structure or the side wall of perforations 12 may be passivated by non conducting material the active material may be in the form of quantum dots in this case the active region 12 does not need to be a bh nor does it require surface passivation since surface recombination rate for quantum dots is fairly low any other relevant and known active material can be employed and employing the bh will be decided depending on the laser design the cavity 25 in this embodiment is air but any other low refractive index material such as sio 2 can be used the low refractive index material should preferably have a refractive index less than about 2 at an operating wavelength of the laser in the case of using a low refractive index material instead of air this layer can be deposited onto the iii v epi structure before bonding since this iii v epi structure does not include a sacrificial layer 20.