Ok, this is a borderline electrical and optical issue so I posted to both groups. I am looking for optical "toggle" switches that are controlled electronically (typically via a highish voltage). Needs to tolerate 500W laser pulses in the IR range, 5-10uJ, average laser power, is less than 100mW, needs >20dB isolation for the off-channel, must switch within very few microseconds (that excludes a lot of them), should be
Perhaps our new laser multiplexer up to 200 optical single channels fills up your demand.
LPM-1 =A8C micro laser perforation at wide web material with high power CO2 dual laser beam multiplexers and splitters, patent grant for process and device DE102004001327.
EU technology links
Links to patent references
patent download:
main link:
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=B8=FC=B6=E0=D0=C5=CF=A2=A3=AC=C7=EB=C1=AA=CF=B5 IPM- International Perforation Management =B9=FA=BC=CA=B9=A4=B3=CC=B9=DC=C0= =ED=B9=AB=CB=BE high-tech engineering - China =A8C Germany - Thailand Mr. Werner Grosse =CD=FE=B6=FB=C4=C7.=BF=CB=C2=DE=C9=AA=CF=C8=C9=FA =B4=AB=D5=E6=A3=BA0049-1212-5-375-17-531 =CD=F8=D6=B7=A3=BA
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We (meaning someone else aligned it) used Pockels Cells for pulse picking of high power IR pulses. But this does not switch the pulse to two different outputs. And the price tag is way out of line!! How about AOM's (acoustic optic modulaltors). I've used these to switch
30 Watt CW lasers in under a microsecond. Not sure of the current price tag or if they can handle high pulse powers. Or do you want something that is fiber coupled?George
Like these?
I am not an optics expert, just designing their electronics, but the optics guru at this client to me that Lithium Niobate switches would degrade or burn up at 500W peak power.
And yes, we must fiber-couple all this stuff.
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How
Yup, those look like AOM's. I noticed one with a peak power of 250 W/ mm^2. Now you need to know things like the aperture into the AOM and what is your laser beam size. But these are not a fiber solution.
George
AODs are medium-latency devices due to the acoustic propagation delay--that few-us number isn't impossible, but it's easier if you have a bit of pipelining happening....how far in advance do you know your pulse pattern?
You can use one fibre in, a collimating lens, an AOD, another lens, and a few fibres in a row for the output. There are people who'd be happy to build that for you (OZ Optics springs to mind), but it wouldn't meet the cost target unless you can amortize over, say, 8 outputs.
To do 1x8 that with ordinary fibre, you'd need about 100 resolvable spots, since the fibre core is about 12 times smaller than the cladding (Resolvable spots = scan range/spot diameter).
Matsushita makes cells like that--I've often used their EFLD-340, which has 340 spots in the visible and about 180 at 1 um.
LCDs have very high damage thresholds but are way too slow.
Another approach would be to use an electrooptical scanner, e.g. a wedge of lithium niobate, to replace the AOD. The key is going to be to use bulk optics for the power level, and amortize the cost over many channels.
Cheers,
Phil Hobbs
Cheers,
Phil Hobbs
The pattern is completely know upon system start so if the latencies are well defined and don't flop about it may be possible.
We will usually have more than a dozen outputs which must be served in round robin fashion, just plain sequentially. We've been through pretty much all domestic sources and the only viable one so far seems to be BATI. But theirs is also still a bit in the early stages.
Right now we are at 1060nm but long term will change to longer and more standard (meaning less $$) wavelengths.
The optical guy at the client told me that most lithium niobate solutions wouldn't be able to handle the pulse power. The mechanical solution we have right now works but it is iffy to push in to higher rpm. It is already running at jet engine rpm.
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They're very very stable--better than 5 ps p-p by my actual measurements--so no problem there. (They're probably better than that even--my measurement was
You can do that with about 150 resolvable spots. You'll need a decent lens on the RX side.
AO cells become more expensive at longer wavelengths, because the diffraction efficiency goes as the phase shift across the crystal thickness, which goes as the optical frequency (it's even a bit steeper than that). Thus you lose efficiency the further you go into the IR. Brimrose is the major supplier out there.
If you can use 820 nm instead, it'll get significantly cheaper.
I think he was talking about niobate waveguides, which are only ~10 um across, vs. a bulk-optics modulator, which would be more like 1 cm.
Cheers,
Phil Hobbs
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h / .Another approach would be to use an electrooptical scanner, e.g. a wedge of lithium niobate,
Hmm how does this work? (mostly I found patents on the web, or journal articles that I couldn't access.) I've measured the Electro- optic effect in Lithium Niobate, (change in the index of refraction for one of the polarization directions with an applied E-field.) But this is a pretty small effect. Does the scanner use the same principle? It must be a real small change in angle.
George
Yes, it's small. You basically build an EO phase modulator, with the E field polarized either along the optic axis or perpendicular to it. The E field changes the refractive index, and Snell's law and the wedge angle turn that into a scanner. You can get a reasonable number of resolvable spots by making the wedge bigger or the beam wider. Niobate has a high half-wave voltage, too. There are EO polymers, but their lifetime isn't that fantastic at present.
Cheers,
Phil Hobbs
I'm about to date myself... are there still Kerr cells ?:-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
Yes, that may be true. I will discuss it some more with him. But right now I am trying to get to a simple design for a half bridge to swing
12V/1A with almost no losses. But my favorite motor drivers have all gone lalaland and the MIC4451 ain't big enough. P/N channel follower has too much crossover. Dang.-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
John Kerr discovered that at a time when the first singing wires were strung in your neck of the woods. A few years later there was the famous O.K. Corral shootout :-)
Are you this old?
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Almost ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine Sometimes I even put it in the food
Come on, Jim. We all know your first design job was the blueprints for Noah's Ark. ;-)
-- http://improve-usenet.org/index.html aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages. If you have broadband, your ISP may have a NNTP news server included in your account: http://www.usenettools.net/ISP.htm There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you\'re crazy.
Naaah! I wasn't the architect... I did the battery back-up ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
Obama ain\'t ever run nothin\' but his mouth!
What backup? It didn't have the capacity to back up. It just drifted with the currents. ;-)
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aioe.org, Goggle Groups, and Web TV users must request to be white listed, or I will not see your messages.
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There are two kinds of people on this earth: The crazy, and the insane. The first sign of insanity is denying that you're crazy.
It did have a controller and needed no backup. But it was not an earthly one ...
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Sure, but they need ~10 kV and contain nasty things like carbon disulphide or nitrobenzene.
Cheers,
Phil Hobbs
Yikes! And here I was fretting over having to generate fast 200V pulses.
Hey, anyone know a MOSFET driver with around 100-200mohm internal Rdson? But not the big Infineon TO220 style, that loses too much efficiency at low power. External p/n channel has too much shoot-through for this circuit. Noise issues, walking on egg shells, the usual.
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