Attenuated VCSEL w/ Back Monitor Photodiode, VCSEL Cathode Common
The HFE408x-321 is a high-performance 850 nm VCSEL (Vertical Cavity Surface-Emitting Laser) packaged for high-speed data communications. This product combines all the performance advantages of the VCSEL with a custom designed power monitor diode. The power monitor diode can be used with appropriate feedback control circuitry to set a maximum power level for each VCSEL. In addition, built-in power attenuation reduces the effective slope efficiency. These combined features simplify design for high data rate communication and eye safety.
The HFE408x-321 is a high radiance VCSEL designed to convert electrical current into optical power that can be used in fiber optic communications and other applications. As the current varies above threshold, the light intensity increases proportionally.
The HFE408x-321 is designed to be used with inexpensive silicon or gallium arsenide detectors (see HFD3081-103, HFD3081-108), but excellent performance can also be achieved with some indium gallium arsenide detectors.
The low drive current requirement makes direct drive from PECL (Positive Emitter Coupled Logic) or EML (Emitter Coupled Logic) gates possible and eases driver design.
The HFE408x-321 is designed to interface with 50/125 and 62.5/125 μm multimode fiber. They product circularly symmetric, non-astigmatic, narrow divergence beams that, with appropriate lensing, fiber couple all of the emitter power
