Passive alignment optical subassemblies for military/aerospace fiber-optic transmitter/receiver applications

Under the DARPA sponsored Avionics Optoelectronic Module Technology program, Boeing, Lucent Technologies, and Ceramics Process Systems have collaboratively developed new passive alignment carrier (PAC) optical subassemblies (LED-PAC and PIN-PAC) ruggedized for military/aerospace avionics fiber-optic transmitter and receiver applications. LED-PAC and PIN-PAC silicon micro-optical bench substrates were fabricated together on a 5 inch diameter silicon wafer via multi-stage photolithography, thin-film, and substrate processing. Alignment v-grooves designed for passive optical alignment of 100/140 μm multimode optical fiber to the optoelectronic devices were terminated by solder locking the fiber to the silicon PAC substrates. The LED-PAC comprising a surface emitting LED die-bonded onto a novel precision molded AlN submount passively mounted onto the silicon microbench achieves the required high coupling efficiency to 100/140 μm multimode optical fiber to meet stringent avionics transmitter output power requirements. The 100/140 μm multimode optical fiber-pigtailed PIN-PAC with a refractive lens etched into the PIN photodiode backside surface exhibited responsivities greater than 0.8 A/W at 1.3 μm wavelength. The LED-PAC and PIN-PAC optical subassemblies integrated with Boeing ARINC 636 (FDDI) Transmitter and Receiver thick film multi-chip (MCM-C) circuitry are capable of meeting both ARINC 636 and FDDI physical layer requirements