- The Distributed Feedback Semiconductor Laser (SDFB), developed during 1970s still powers the worldwide optical fibre network.
- The SDFB Laser’s thin unparallelled spectral purity ensured its unusual longevity in optical communications. But, ts spectral purity no longer satisfies the present demand for bandwidth.
- The crystalline layers of material (III-V Semiconductor -strong light absorbers), which makes up the old laser, convert the applied electrical current into light. But, since this absorption leads to degrading of spectral purity, a different solution was being sought.
- The news laser uses the same III-V Semiconductor material & converts electric signals into light, but stores light thereon on a layer of silicon, which doesn’t absorb light, thus achieving high spectral purity, with a 20 time narrower range of frequencies when compared to the older ones.
- Distributed Feedback Semiconductor Laser (SDFB)
- Spectral Purity