Uncooled high-speed DFB lasers for gigabit ethernet applications

Abstract

Uncooled DFB lasers directly modulated at 10 Gbit/s are a key devices for Optical communication systems operating at 10 Gbit/s, such as 10 Gbit Ethernet, since their effective use in optical transceivers to reduce cost, size and power consumption. The paper describe the current status of these sources (including well assessed InGaAsP MQW and recent progress for AlGaInAs MQW active layers), as well as the Agilent's very recent results. Combining an optimised active region based on InGaAsP strained MQW (Multi Quantum Well) and a low parasitic lateral confinement region, we have fabricated 10 Gb directly modulated uncooled DFB lasers which represent, we believe, the state of art. Our DFB lasers work up to 100 °C (chip temperature), with eye diagram perfectly open (showing an extinction ratio > 5 dB), and with Bit Error Rate over 10 km without error floor. Up to 90 °C our DFBs show threshold current as low as 29 mA, optical power as high as 13 mW and meet perfectly 10 Gb scaled Ethernet mask with extinction ratio > 6 dB

Reliability of 1310 nm Wafer Fused VCSELs

“…C OMPARED with un-cooled 1310 nm distributedfeedback (DFB) lasers, 1310 nm vertical cavity surface emitting lasers (VCSELs) for transmission at 10 Gbps, based on either InGaAlAs/InP [1]- [3], or GaInNAs/GaAs [4] active regions offer about 10 times reduction of bias current in the full operating temperature range. Typically, with 1310 nm VCSELs, 10 Gbps transmission over 10 km at 80 °C can be performed at 8-9 mA bias current (Ref.2), while with DFBs [5] similar performance is reached at currents of 80 mA. This feature becomes especially important when building wavelengthmultiplexed transmitter modules like, for example, 4×10 Gbps coarse-wavelehgnth division-multiplexing (CWDM) modules emitting at 1271, 1291, 1311 and 1331 nm according to the recent 40 GbE IEEE 802.3ba standard [6].…”