Modulation instability wavelength converter

A wavelength conversion device comprising;

• a non-linear loop mirror including a non-linear single mode optical waveguide fiber having a first and a second end, a zero dispersion wavelength .lambda..sub.o, and, a non-linear index greater than about 3(W-km).sup.-1 ;
• a first coupling means for coupling of signal pulses of wavelength .lambda..sub.s to the non-linear loop mirror fiber, propagating in one direction in the non-linear optical loop mirror;
• a second coupling means for coupling pump pulses .lambda..sub.p to the non-linear loop mirror fiber, propagating in counter-current directions in the non-linear loop mirror;
• wherein, the pump and signal pulses are synchronized to overlap at least partially during at least a part of the time spent traversing the non-linear loop mirror so that the pump pulses convert the wavelength of the signal pulses, and pump energy is transferred to both the signal pulses and converted pulses;
• and, wherein,
• the non-linear loop mirror is balanced to reflect the pump pulse wavelength, and, a third coupling means couples the signal and converted pulse wavelengths out of the non-linear loop mirror fiber.

A wavelength conversion device comprising:

• a coupler having at least first and second input ports and at least a first output port;
• a first single mode waveguide fiber, propagating signal light pulses of wavelength .lambda..sub.s, connected to the first input port;
• a second single mode waveguide fiber, propagating pump light pulses of wavelength .lambda..sub.p, connected to the second input port;
• the signal light pulses and the pump light pulses exiting the coupler through the first output port which is connected to a first end of a third single mode waveguide fiber having a zero dispersion wavelength .lambda..sub.O, the signal pulses and the pump pulses being synchronized to overlap at least partially for at least a portion of their travel time in the third waveguide fiber;
• in which, .lambda..sub.p is greater than .lambda..sub.O, and the first waveguide fiber comprises a first single mode waveguide segment, in which total linear dispersion decreases in the direction of light propagation, and, a second single mode waveguide segment having substantially constant total linear dispersion.

A method for converting wavelength of a light signal pulse comprising the steps:

• a) launching signal light pulses of wavelength .lambda..sub.s into a first single mode waveguide fiber;
• b) launching pump light pulses of wavelength .lambda..sub.p into a second single mode waveguide fiber;
• c) by means of a coupler having at least two input ports and at least one output port, coupling the signal pulses and the pump pulses into a third single mode waveguide fiber having a zero dispersion wavelength .lambda..sub.O connected to the at least one coupler output port;
• d) filtering the pump light pulses from the third waveguide at a position spaced apart from the at least one coupler output port;
• and,
• e) synchronizing the signal pulses and the pump pulses so that at least a portion of the signal pulse overlaps in time at least a portion of the pump pulse over at least a portion of the travel time of the signal and pump pulses in the third waveguide;
• in which, .lambda..sub.p >.lambda..sub.o and the non-linearity constant of the third waveguide fiber is in the range of about 3 (W-km).sup.-1 to 13 (W-km).sup.-1.