| Optical interconnects for silicon electronics have been shown to have many advantages over traditional electrical interconnects, particularly in dense, high-capacity systems. One approach used to achieve the very high data rates used in telecommunications today is wavelength division multiplexing (WDM). As bandwidth needs increase, WDM becomes an attractive solution for shorter distance links as well, such as chip-to-chip or board-to-board interconnects. While telecommunications WDM systems traditionally use a separate laser for each wavelength channel, a simpler, less expensive alternative is needed for interconnects on scales of a few meters or less. One such solution is to use a single, broadband laser source.; In this work, operation of a 10-channel chip-to-chip WDM optical interconnect using a modelocked Ti:Sapphire laser and surface-normal electroabsorption modulators is demonstrated. The short pulses from a modelocked laser have a broad spectral bandwidth, which allows the wavelength channels to be defined by spectral slicing of a single source. However, the short pulse duration, high peak power, and low jitter of these pulses provide additional advantages in optical interconnects, several of which will also be discussed. The possible performance limitations of such a WDM interconnect are explored, and several future improvements are proposed.; Many of the wavelength-separating devices used for WDM, such as arrayed waveguide gratings (AWGs), are complex to fabricate and relatively costly. Other de-multiplexers include traditional dispersive devices, such as diffraction gratings and prisms. While being much simpler and less expensive than AWGs, these devices typically have an angular dispersion less than one degree/mm, which prevents them from being sufficiently compact. Recent work suggests that the “superprism effect” of periodic structures may provide a compact alternative, with angular dispersion many times higher than that of a conventional grating or prism. This work experimentally demonstrates that the same beam-steering effect, previously shown for 3D photonic crystals, exists in a simple 1D dielectric stack structure, and discusses its possible application within WDM systems. |
