Wideband Multimode Fiber Research Articles

Wideband multimode fiber with an optimized core size and fluorine-doped cladding for high-speed SWDM and CWDM transmission.

We propose a novel multimode fiber (MMF) with a 30 μm-core and fluorine-doped cladding for both high-speed short wavelength division multiplexing (SWDM) and coarse wavelength division multiplexing (CWDM) transmission. By optimizing the core size, the mode field diameter (MFD) mismatch between the proposed fiber and both the standard single-mode fiber (SMF) and MMF is minimized, which enables the quasi-single mode operation in the CWDM window and a compromised coupling loss with standard MMFs and SMFs. By adopting a fluorine-doped silica cladding, the bandwidth dependence on wavelength of the proposed fiber is minimized, which indicates that the modal bandwidth performance at the longer wavelength can be effectively improved without compromising modal bandwidth at 850 nm. The error-free 100 Gb/s (4×25.78 Gb/s) multimode transmission over 250 meter-long fiber is achieved using a commercially available VCSEL-based SWDM transceiver. The applicable distance can be extended to 300 meters when a biterror rate just below the forward error correction (FEC) threshold of 5×10-5 is acceptable. Besides, the 100 Gb/s error-free single-mode transmission over 10 km-long fiber was also demonstrated with a commercially available directly modulatedlaser (DML)-based CWDM transceiver. The results imply that the proposed MMF may be useful for large-scale data center applications.

Scaling VCSEL-MMF Links to 1 Tb/s Using Short Wavelength Division Multiplexing

We demonstrate a path to 1-Tb/s VCSEL-based links using a wideband multimode fiber (WBMMF/OM5), which provides an extended effective modal bandwidth ranging from 844 to 948 nm. Using 850-, 880-, 910-, and 940-nm vertical cavity surface emitting lasers (VCSELs), we quantify the benefits of electronic pulse-shaping and channel equalization for both pulse-amplitude modulations (PAMs), i.e., PAM-2 and PAM-4. We demonstrate that all these VCSELs support an error-free performance (bit error rate <10−12) at 54 Gb/s for PAM-2 and at 84 Gb/s for PAM-4 over 100 m of OM5 without forward error-correction (FEC) or receiver equalization. Furthermore, all VCSELs support 100-Gb/s PAM-4 transmission over 100 m of OM5 with FEC and receiver equalization. Importantly, all signal filtering investigated is readily implemented in SiCMOS.