What is the difference in performance, between a link with a high optical power semiconductor laser, and a link with a low optical power semiconductor laser + a boosted optical amplifier? Suppose that they have the same output optical power.
Of course there is. In case of direct diode laser you have [fast axis, slow axis] divergences and source sizes, and respective near zone space profiles. In case of fiber-coupled diode laser you have optical invariant OI = [NA_fiber x Core_hemiDia). High power semiconductor lasers typically have poor beam quality and respectively, require large diameter fibers for coupling. So OI is large too. BOAs principally can have fundamental-mode output. So in this case OI can be as small as diffraction limit allows. Then, OI is the main macroscopic factor of optical system. It keeps constant throughout a system. The smaller OI, the better focusing of a beem is achieved. So basically BOA allows comsiderably tighter focusing than fiber coupled diode. In turn, direct diode focusing leads to considerably worse results than focusing of fiber-coupled diode.
Hi Moschim, with a high optical output laser your OSNR will be higher than a low power laser + EDFA.
This is the difference.
Regards.
I agree with the others. If you are concerned with maximizing power to a spot or to an application the optical fiber approach with better beam quality may be very helpful. If you want to minimize noise you may want to examine the trade offs more closely depending on the application.
Many differences.
First the "power" itself. A typical high-performance telecom laser will not go much higher than +6dBm; whereas an EDFA will easily boost a 0 dBm laser to +18 dbm (which is a lot of power!!)
second, Noise :: keeping the laser itself at lower power levels reduces all kinds of noise (flicker, ASE, chirping, so on);
third, lifetime:: optical amplifiers are built with high-power durable lasers, which can withstand rough conditions; on the other hand, telecom lasers are more sensitive and should be operated at moderate powers to guarantee extended lifetime.
- Badges
- Science topic
- Similar topics
- Biological Science
- Molecular Cell Biology
- Culture Cells
- Cell Line