US 6,204,944 B1Granted

All-optical time-division demultiplexing circuit and all-optical TDM-WDM conversion circuit

AssigneeNippon Telegraph and Telephone Corporation

InventorsKentaro Uchiyama, Satoki Kawanishi, Masatoshi Saruwatari

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Abstract

An all-optical time-division demultiplexing circuit is designed to output all the channels of time-division multiplexed signal pulses to different output ports simultaneously. A pulse stream of time-division multiplexed signal pulses and linearly chirped control pulses synchronized with the signal channels are input into an optical Kerr medium. The optical Kerr medium provides locally cross-phase modulation to the control pulse, depending on the presence or absence of the signal pulses of each signal channel. And the optical Kerr medium modulates the power of the component frequencies υ1, υ2, . . . , υN of the control pulses in accordance with each of the signal channel, by inducing the optical frequency shift to compensate the control pulse chirp on the optical frequency axis. The Kerr medium outputs a power modulated control light, which is separated in a wavelength-division demultiplexing circuit into component frequencies υ1, υ2, . . . , υN of the control pulses which are to output to respective ports of corresponding to individual signal channels.

Claims16

Dependent claims

An all-optical time-division demultiplexing circuit, for separating time-division multiplexed optical pulses, comprising:

optical power adjusting means for receiving an optical pulse stream of time-division multiplexed signal, of a signal frequency υs, comprised of N signal channels, where N is an integer greater than or equal to 2, and outputting power-adjusted signal pulses;
a control light source for generating control pulses which have the same repetition rate as said signal channels, and which are synchronized with signal channels of said time-division multiplexed optical pulses, and whose optical frequency varies monotonically from a leading end to a trailing end and is different from said signal optical frequency υs, and which have a pulse duration sufficient for a total inclusion of said N signal channels;
optical wavelength-division multiplexing means for multiplexing an optical pulse stream of time-division multiplexed signal power-adjusted by said optical power adjusting means and said control pulses;
an optical Kerr medium for receiving output signal by said optical wavelength-division multiplexing means, producing cross-phase modulation locally on the time axis to said control pulses depending on the presence or absence of signal pulses in said signal channel of said time-division multiplexed optical pulses, and power modulating said control pulse of component frequencies υ1, υ2, . . . , υN corresponding to said each signal channel by inducing an optical frequency shift of said chirped control pulse to compensate on the frequency axis;
optical wavelength-division demultiplexing means for receiving light output by said optical Kerr medium, separating said control pulse of component frequencies υ1, υ2, . . . , υN corresponding to signal channels of said time-division multiplexed optical pulse stream, and outputting to respective ports of corresponding individual optical frequencies.

2 more elements

An all-optical conversion circuit for converting time-division multiplexed signal to wavelength-division multiplexed signal, comprising:

optical power adjusting means for receiving an optical pulse stream of time-division multiplexed signal pulses, of an optical frequency υs, comprised of N signal channels, where N is an integer greater than or equal to 2, and outputting power-adjusted time-division multiplexed signal pulses;
a control light source for generating control pulses which have the same repetition rate as said signal channels, and which are synchronized with signal channels of said time-division multiplexed optical pulses, and whose optical frequency varies monotonically from a leading end to a trailing end and is different from said signal optical frequency υs, and which have a pulse duration sufficient for a total inclusion of said N signal channels;
optical wavelength-division multiplexing means for multiplexing a control pulse with said power-adjusted time-division multiplexed signal pulses, and outputting a superimposed signal;
an optical Kerr medium for receiving output signal by said optical wavelength-division multiplexing means, producing cross-phase modulation locally on the time axis to said control pulses depending on the presence or absence of signal pulses in said signal channel of said time-division multiplexed optical pulses, and power modulating said control pulse of component frequencies υ1, υ2, . . . , υN corresponding to said each signal channels by inducing an frequency shift of said chirped control pulse to compensate on the frequency axis;
and
optical wavelength-division demultiplexing means for receiving light output by said optical Kerr medium, separating said time-division multiplexed signal pulses of frequency υs from control pulses of frequencies υ1, υ2, . . . , υN;
and outputting a second optical pulse stream of wavelength-division multiplexed pulses to replace said first optical pulse stream of time-division multiplexed pulses.

4 more elements

Dependencies are inferred from the claim text.