New materials and new structures for uncooled sources suitable for datacom and telecom applications

Abstract

Optical communication systems operating at 10 Gbit/s such as 10 Gigabit Ethernet (GbE) are becoming more and more important, even in Local Area Networks (LAN) and Metropolitan Area Networks (MAN). This market requires optical transceivers of low cost, size and power consumption, driving a need for "hot" transmitter: uncooled DFB lasers directly modulated at 10 Gbit/s for short link (up to 10 km) and high operating temperature integrated (hybrid or monolithic) solution, like laser and electro absorption modulator at 10 Gbit/s, for longer distance (40 - 80 km). The paper describes the current status of these devices for different applications. We will report results on uncooled high speed 1300 nm DFB laser which is capable of being manufactured in high volume at the low cost demanded by the GbE market. Combining an optimized active region based on InGaAsP strained MQW (Multi Quantum Well) and a low parasitic lateral confinement region, we have fabricated 10 Gbit/s directly modulated uncooled DFB lasers which work up to 100°C (chip temperature), with eye diagram perfectly open (showing an extinction ratio > 5 dB @ 100°C), and with Bit Error Rate over 10 km without error floor up to 10^-12. We will report the optimization and the results of an electro-abosorption modulator (EAM) based on quantum confined Stark effect in strained multiple quantum wells (MQWs), suitable for 40 - 80 km propagation of 10Gb/s optical signals on standard single-mode fiber at 1550 nm. The MQW structure has been designed and fabricated to obtain high extinction ratio, low insertion loss and negative chirp at 1550 nm, 60°C. Devices demonstrated a contrast ratio of above 10 dB, insertion loss of 5 dB and a negative chirp at 10 Gb/s, 60°C with a voltage swing of 2 V.