Title | High-Speed Bi-Directional Communication using Optically Injection-Locked Semiconductor Lasers |
Publication Type | Conference Proceedings |
Year of Conference | 2008 |
Authors | Chrostowski, L., Q. Gu, W. Hofmann, and M. - C. Amann |
Date Published | 05/2008 |
Abstract | Tremendous improvement in the performance of directly modulated 1.55 um Vertical Cavity Surface Emitting Lasers (VCSELs) has been obtained by using the Optical Injection Locking (OIL) technique. OIL uses a second laser to inject photons at a similar wavelength into the transmitter laser; the transmitter laser is thus locked (in wavelength and phase) to the master due to the coherent non-linear interaction in the cavity, which leads to significant changes in the dynamic properties of the laser. Specifically, the resonance frequency can increase from 5 GHz to over 50 GHz, thereby increasing the modulation bandwidth. Recently, our group has discovered that an OIL-VCSEL can function as a receiver, while the VCSEL forward-biased. This is a surprising effect, particularly since conventional reverse-biased VCSEL structures show a low responsivity and bandwidth. We have observed a small-signal modulation bandwidth of 20 GHz, and experimentally demonstrated large-signal digital modulation with a data-rate up to 12 Gb/s. Under an identical forward-bias condition, the OIL-VCSEL can function both as a transmitter and as a receiver, potentially with a similar bandwidth enhancement as previously reported for the transmitter case. This exciting discovery opens the possibility of high-speed bi-directional optical interconnects using a single directly-modulated laser. |