Dear All, I require some information about delay in microwave signal. I think it is possible by changing microwave signal to optical signal and use of optical fiber for delay and thus detection of signal by a high speed photodetector. I want some delay in microwave carrier signal and we should not lose any information for example phase and a ramp signal on microwave carrier signal. Is there anyone who knows about that? Is it possible some delay by optical fiber? Are there all optical components (for example high speed optical modulator and high speed photodiod for detection of 5 GHz) for this experiment.
delay for microwave signal!?
Nov 27, 2004
12 Replies
How much delay do you need? There are trombone and switched-transmission line variable electrical delay boxes, and slotted waveguides with probes.
Does anybody make telescoping waveguides?
5 GHz is a bit fast for modulating a laser, so you'd probably need a cw laser driving a lithium niobate fiber modulator (many kilobucks), a driver (5 volts p-p maybe), some fiber-to-freespace optics, and a fast photodetector (under a kilobuck, maybe). Then some sort of controlled, variable optical path.Why not a couple of microwave antennas?
John
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John
Bounce it off of something? If you need a long delay use the Moon.
;-)
- YD.
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I have often wondered the same thing. Just out of curiosity, what is your application? I'd certainly appreciate it if you could keep us advised.
--Mac
Heh, nice article :-)
- YD.
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The optical path just adds complexity, cost and noise, and gains little. In case the delay is fixed, take a few meters of waveguide. In case the delay is to be adjustable, an adjustable waveguide with some discrete varactors should do it. By adjustable waveguide I was thinking of a ridge waveguide, that is squeezed to increase the inductance. If the delay is to be adjustable, what is the speed of the adjustment, meaning the tuning bandwidth ?
Rene
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The use of optical fibre for delay with wide bw is well known. The key factor is attenuation per metre. A low loss cable at 2ghz will have many db for 100m metres whereas a good glass optical fibre will have 1 to .1db per km hence long depay with practical loss.
ddwyer
Recently I found out a company that have a Fiber-Optic Delay Line. It is
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this product can delay up to 200us and bandwidth>15GHz. But I don't know can it mantain initial phase of microvave carrier signal?
I will be very glad if everybody can introduce another company or any suggestion/hints/refrences.
Best, Hashem
You are right and I found out a company for that
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I require some articles or notes about design of this system. I will be very glad if everybody can give me some advice or references.
Best, Hashem.
When we require delay>10us we mus used waveguide>3km and It is not possible becase of high attnuation and we have to use optical fiber delay line!
How about using a SAW delay line?
Paul Hovnanian mailto:Paul@Hovnanian.com
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Thanks, Hashem. That looks like a capable unit.
I don't understand what you mean by "initial phase" of the microwave signal. As long as you observe the frequency and power limits of the apparatus, its operation is pretty simple: the signal goes in the input, and 200 us later the same signal comes out.
What do you need this delay line for?
--Mac
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