In message , dated Tue, 5 Sep 2006, Phil Hobbs writes
Then insist on pronouncing 'EPIC' as 'epique', Follow up with 'comique', 'musique' etc., until you drive him frantique.
-- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK
So what might the on-chip modulators like? I've worked with the active polymer boys (Lightwave) and the thinfilm sol-gel plzt guys (Teloptics), and so far nothing is practical, usually because the stuff can't be processed well and the drive voltages are way too high. Polarization problems, too.
John
The leading candidate is a ring resonator, whose resonance can be tuned by injecting a little current into the ring--the carrier density changes the refractive index, which moves the resonance. It's basically a notch filter that gets tuned back and forth across the laser wavelength to make an amplitude modulator. You damage the silicon to shorten the minority carrier lifetime (shades of gold-doped TTL). Rings work very well, and you can make them today. The bad news is that their resonances are very temperature-sensitive, so they have to be stabilized somehow if you want to run them at high Q, which is necessary to get low drive power.
The dark-horse candidate is my antenna-coupled tunnel junction gizmo, which (if it works as well as I hope) will do the modulation job with about 1% of the power, 2% of the chip area, and without the wavelength sensitivity or temperature drift. Currently I have detectors working at about 5% quantum efficiency, and I expect to have working modulators this month--though what their efficiency and modulation depth will be, I don't know yet.
Cheers,
Phil Hobbs
Yeah, well, once I don't need his money, I can be much more amusing....
Cheers,
Phil Hobbs
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