Optical time domain reflectometer calibration system

Claim 1

A system for calibrating an optical time domain reflectometer (OTDR) having a screen, comprising: a) fiber optic connector means having one end connected to said OTDR for receiving optical pulses from said OTDR for calibration purposes; b) optical switch means connected to the other end of said fiber optic connector for receiving said optical pulses and for transmitting said pulses in alternate paths; c) a two-by-two bidirectional coupler disposed to receive said optical pulses transmitted in either of said paths by said optical switch means and for splitting said pulses into two streams; d) means for receiving one of said streams of optical pulses and for converting said stream of optical pulses into an electrical triggering signal having electrical pulses comparable to said optical pulses; e) amplifier means for receiving and amplifying said electrical triggering signal; f) means for transmitting said amplified electrical triggering signal; g) digital delay pulse generator means for receiving said amplified electrical triggering signal to trigger said generator means to produce two delayed output signals, each containing spaced electrical pulses correlated with said electrical triggering signal; h) balanced Y circuit means for combining said two delayed output electric signals into a single electric signal wherein said spaced electric pulses are correlated with each other and with said triggering signal and have the same time delay as the electrical pulses produced by said digital delay pulse generator; i) laser diode/driver means disposed to receive said single electric signal from said balanced Y circuit means and for converting said single electric signal into an optical signal having spaced optical pulses having the same time delay as the electrical pulses produced by said pulse generator; and j) means for transmitting said optical signal to said OTDR wherein said signal is displayed on the screen thereof for comparison purposes and for calculating the relative distance between said spaced pulses in order to determine the accuracy of said OTDR calibration.

Claim 2

A system for calibrating an optical time domain reflectometer (OTDR) having a screen, comprising: a) fiber optic connector means having one end connected to said OTDR for receiving optical pulses from said OTDR for calibration purposes; b) optical switch means connected to the other end of said fiber optic connector for receiving said optical pulses and for transmitting said pulses in alternate paths; c) a two-by-two bidirectional coupler disposed to receive said optical pulses transmitted in either of said paths by said optical switch means and for splitting said pulses into two streams; d) means for receiving one of said streams of optical pulses and for converting said stream of optical pulses into an electrical triggering signal having electrical pulses comparable to said optical pulses; e) amplifier means for receiving and amplifying said electrical triggering signal; f) means for transmitting said amplified electrical triggering signal; g) digital delay pulse generator means for receiving said amplified electrical triggering signal to trigger said generator means to produce two delayed output signals, each containing spaced electrical pulses correlated with said electrical triggering signal; h) balanced Y circuit means for combining said two delayed output electric signals into a single electric signal wherein said spaced electric pulses are correlated with each other and with said triggering signal and have the same time delay as the electrical pulses produced by said digital delay pulse generator; i) laser diode/driver means disposed to receive said single electric signal from said balanced Y circuit means and for converting said single electric signal into an optical signal having spaced optical pulses having the same time delay as the electrical pulses produced by said pulse generator; and j) means for transmitting said optical signal to said OTDR wherein said signal is displayed on the screen thereof for comparison purposes and for calculating the relative distance between said spaced pulses in order to determine the accuracy of said OTDR calibration.