Laser-diode array packaging in opto-electronic multichip modules

An opto electronic multichip module (OE-MCM) constructed from optical polyimide waveguides on an OE substrate has been developed for high-speed, wideband communication systems. This paper describes the packaging of the laser-diode (LD) array on the OE substrate, which is composed of low-loss (0.4 dB/cm at 1.3 μm) optical polyimide waveguides on a copper-polyimide multilayer substrate. High-speed (Gbit/s) electrical signals are transmitted through electrical lines in the copper-polyimide layers. A junction-up, five-channel InGaAsP edge-emitting LD array is aligned to the waveguides in the plane direction with an error margin of 2 μm by using a standard surface for vertical positioning. The bottom of the LD array is connected to columnar thermal vias under the bonding area for heat dissipation. The emitted light power is considered to be stable because no kinks and good linearity are observed in the I-L characteristics of the coupled LD array. The coupling loss was estimated to be 6.5 dB with a deviation between channels of ±0.3 dB