An integrated DWDM
transmitter apparatus includes a support component and a silica-on-
silicon substrate overlying the support component. The support component includes a temperature adjustment component. The silica-on-
silicon substrate overlies the support component and includes a silica layer and a
silicon layer. The silica-on-silicon substrate includes a corresponding a
substrate surface which includes a first surface region and a second surface region. In an embodiment, the two surface regions are not coplanar. The
transmitter apparatus includes an optical
multiplexer within the silica layer, the optical
multiplexer including a plurality of input waveguides and at least an output
waveguide. The
transmitter apparatus also includes one or more
semiconductor laser array chips overlying the first surface region of the silica-on-silicon substrate. Each of the
laser array chips including two or more lasers, which are optically coupled to corresponding ones of the plurality of input waveguides.