Loss analysis for optical MCM based optical link

Sources of loss occurred in optical MCM (multi-chip module) based optical link is investigated by simulations. An optical MCM is composed of an organic substrate, polymer waveguides, optochips, and connectors. In an optical link, two optical MCMs played as data transmitter (TX) and receiver (RX) are connected by a multimode fiber (MMF). Polymer waveguides are laminated and optochips are flip chip bonded on the organic substrate. At the entrance and end of each waveguide, there are a pair of turning mirrors. In TX, the light is emitted by a vertical-cavity surface-emitting laser (VCSEL) and then go through the upper cladding layer. After reflected by a turning mirror the light propagates along a 1-cm long straight polymer waveguide. At the waveguide end, light is reflected again and propagate toward a MMF. Coupling between waveguide and MMF is realized by a double lens connector. In RX, light comes from the MMF and propagates as similar way, and is collected by a photo diode (PD). The total link loss includes loss caused by turning mirror roughness is about 5 dB. This helps us to optimize link design for dense aligned high-speed optical MCM link system.