Optical interconnection applications of diode lasers

High-efficiency lasers that can be directly driven by digital logic circuits with no additional driver circuitry are attractive for interconnection applications. Lasers with the desired characteristics have been made. This device has a threshold of 4 mA, over 10 mW of output power at 25 mA, and over 60% differential quantum efficiency. The -3-dB frequency of this particular laser is over 10 GHz at 25 mA. Lasers of this type are sufficiently efficient that diode lasers and detectors can be connected directly to digital gates without additional drivers or preamplifiers. A free-space board-toboard interconnection3 achieved 19% differential current efficiency and operated at 1 Gb/s, a rate limited by the logic circuitry. The average power dissipation on the transmitter side of the link is estimated to be 20 to 25 mW for bit patterns with an equal probabilility of 1´s and 0´s. The average power dissipation of the receiver is also about 20 mW.