Re: [time-nuts] Using lasers for data transmission

On 1 May 2016 15:02, "Bruce Griffiths" wrote: > > The solution with high power is to use a beam expander so that the unaided eye cannot collect a power greater than the safe limit. Using near IR beams also helps. > Bruce It is a long time since I worked with lasers,

Re: [time-nuts] Using lasers for data transmission

Thank you, I personally were talking about 1400nm 1mw lasers, however. Supplying just above the threshold current is not a problem. does the raising time can be reduced if using lower current/voltage raises or falls? I mean: how's calculated the raise time, full-scale pulse or for a mW/mA or

Re: [time-nuts] Using lasers for data transmission

On 5/1/16 9:48 AM, Mark Sims wrote: There are "eye-safe" wavelengths that some laser diodes can operate at (generally greater than 1300 nm). These are much less prone to damage eyes. Basically your eyeball juice blocks the wavelength. Still, there is some potential for cornea and lens

[time-nuts] Using lasers for data transmission

Also, a lot of laser diodes don't like to be "cold-started". Your modulation scheme needs the laser to always be on at some minimum level above Ith. Just crudely switching from off to on can quickly kill the diode.

[time-nuts] Using lasers for data transmission

There are "eye-safe" wavelengths that some laser diodes can operate at (generally greater than 1300 nm). These are much less prone to damage eyes. Basically your eyeball juice blocks the wavelength. Still, there is some potential for cornea and lens damage at higher powers.

Re: [time-nuts] Using lasers for data transmission

On 5/1/16 3:22 AM, Bruce Griffiths wrote: The solution with high power is to use a beam expander so that the unaided eye cannot collect a power greater than the safe limit. Using near IR beams also helps. Bruce IR is a problem for eye safety, because IR doesn't trigger the blink reflex, so

Re: [time-nuts] Using lasers for data transmission

Dear Ilia On Sun, May 1, 2016 at 6:40 PM, Ilia Platone wrote: > The problem would be modulating a 10GBASE-T signals into a single laser > beam, and demodulating it using (I think) an APD. > The White Rabbit cards use SFP (small form-factor pluggable) lasers that plug into

Re: [time-nuts] Using lasers for data transmission

The solution with high power is to use a beam expander so that the unaided eye cannot collect a power greater than the safe limit. Using near IR beams also helps. Bruce On Sunday, 1 May 2016 9:00 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: >

Re: [time-nuts] Using lasers for data transmission

Threshold current should not be a problem because if there's no data the laser could go into "power saving mode". As am modulation a simple buffer/r2r network DAC should do the job. The signals to transmit are three: Tx, and two bidirectional. Ilia. Il 01/05/2016 10:27, Dr. David Kirkby

Re: [time-nuts] Using lasers for data transmission

> Hi, > Several (many?) years ago National Geographic magazine show a picture taken here in southern California of the state government sending red laser signals between different mountain tops to keep track what was going on near fault lines > There were no technical details on what was taking

Re: [time-nuts] Using lasers for data transmission

The problem would be modulating a 10GBASE-T signals into a single laser beam, and demodulating it using (I think) an APD. except the one depending on light travel, that shouldn't be a problem if using White Rabbit, there could be some problem with the modulating and transmitter/receiver delay

[time-nuts] Using lasers for data transmission

Hi, Several (many?) years ago National Geographic magazine show a picture taken here in southern California of the state government sending red laser signals between different mountain tops to keep track what was going on near fault lines. There were no technical details on what was taking