Waveguide nonlinear optical frequency converter with integral modulation and optimization means

A method for converting the frequency .omega..sub.in of an input signal to create an output signal having frequency .omega..sub.out and modulating the intensity of the output signal, comprising the steps of:

• (a) inputting the input signal into a waveguide including a nonlinear active region having a length L and a periodically poled grafting of period X, in which the input signal has one of a TM and a TE polarization state;
• (b) switching the polarization state of the input signal between the TE and TM polarization states;
• and
• (c) quasi-phase-matching the input signal and the output signal.

A method for converting the frequency .omega..sub.in of an input signal to create an output signal having frequency .omega..sub.out and optimizing the efficiency of the frequency change, comprising the steps of:

• (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poles grating of period X;
• b) varying the dispersion of the active region to maintain a coherence length between the input and output signals equal to the value (n/2)X, where n equals an odd integer;
• c) quasi-phase-matching the input signal and the output signal;
• and
• (d) monitoring the power of the output signal while electro-optically varying the dispersion of the active region to maintain optimum output signal power.

A method for converting the frequency .omega..sub.in of a polarized input signal to create an output signal having frequency .omega..sub.out and modulating the intensity of the output signal, comprising the steps of:

• (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poled grating of period X;
• (b) alternating the polarization state of the input signal between one of a TE and TM polarization state prior to propagating the signal through the active region;
• (c) quasi-phase-matching the input signal and the output signal;
• and
• (d) changing the dispersion of the active region to maintain a coherence length between the input and output signals equal to one-half of the grating period of the active region.

A method for converting the frequency .omega..sub.in of an input signal to create an output signal having frequency .omega..sub.out and modulating the intensity of the output signal, comprising the steps of:

• (a) inputting the input signal into a waveguide including a variable dispersion, nonlinear active region having a length L and a periodically poled grating of period X for quasi-phase-matching, in which the input signal has one of a TM and a TE polarization state;
• (b) switching the polarization state of the input signal between the TE and TM polarization states;
• and
• (c) quasi-phase-matching the input signal and the output signal.

A quasi-phase-matching frequency converter for optimizing the efficiency of quasi-phase-matched frequency conversion from an input signal of frequency .omega..sub.in to an output signal of frequency .omega..sub.out, where .omega..sub.in is different from .omega..sub.out comprising:

• (a) a waveguide including an active region of characteristic length L having quasi-phase-matching frequency conversion means and variable dispersion;
• and
• (b) integral means for electro-optically varying the dispersion of the active region;
• (c) detecting means opto-electronically responsive to the output signal for continuously measuring the output signal power, and feedback means for dynamically controlling the dispersion varying means.