with reference to fig1 there is shown in schematic form a diagram depicting our inventive optical wavelength converter 100 . it includes a semiconductor optical amplifier ( soa ) 110 monolithically integrated with a delayed interference loop 120 which may be formed by a tunable or fixed , but asymmetric splitting ratio coupler 130 and a coupler 140 , e . g ., a 2 × 2 or 1 × 2 coupler . as can be readily appreciated by those skilled in the art , a longer arm 125 of the delayed interference loop 120 provides a δt delay and shorter arm 127 of the delay interference loop 120 includes a phase shifter 150 . the device converts and reshapes a pulsed input signal p in at λ 1 into the wavelength converted signal p conv at λ 2 . the pulsed input signal p in modulates the phase and the gain of copropagatmg cw signal p cw in the soa . the rise time of the phases shift in the p cw signal is almost instantaneous and limited by the pulse width of the p in signal , whereas the fall time is limited by the slower , carrier recovery time . the power of an input pulse is chosen such that it modulates the phase of the cw signal by an amount , π . upon exiting the soa , the p cw signal is asymmetrically split between the longer arm 125 and the shorter arm 127 of the delayed interference loop 120 through the action of the asymmetric splitting ratio coupler 130 . after traversing the respective arms of the interference loop 120 , the signals are combined by coupler 140 . the coupler 140 directs the p cw signal into a p inv output port if the two signals in the two arms of the interference loop have an equal phase , whereas it couples the signal into the p conv output port if the phase difference is π . the signal traversing the shorter arm 127 of the delay interference loop 120 carries the π phase shift first reaches the coupler 140 , and open a “ switching window ” for the p conv output port . at approximately δt = 10 ps later , the p cw signal reaches the coupler 140 , the phase difference is reset and the switching window in the p conv port closes . in an exemplary construction , ingaasp / inp wavelength converters may be grown by conventional metal organic vapor phase epitaxy on ( 001 ) inp . the separate confinement heterostructure soas , having a length of approximately 1 . 2 mm may be grown first . subsequently , the spotsize converters and passive waveguide layers are regrown using a butt coupling scheme to connect the two different layers in the same plane . waveguides , couplers and phase shifters are defined by a wet etching step . the radius of the curved waveguides is substantially 250 μm and the total waveguide losses are below 3 db . a doped , ingaas layer is grown on top of the active sos sections and phase - shifter sections to provide ohmic contacts . a representative size of such a packaging construction is approximately 6 × 1 . 3 mm . subsequently , input and output ports may be fiber - pigtailed and the integrated device so constructed may be mounted with a temperature cooling unit into an additional ( i . e ., “ butterfly ”) package . as noted previously albeit more generally , our inventive device converts and reshapes a rz input signal p in at λ 1 into a wavelength - converted signal p conv at λ 2 . the rz input signal p in modulates the gain of the soa and thereby the phase φ cw of the copropagating cw signal p cw ( left bottom inset of fig1 ). the power of the rz input signal has to be adapted such that it modulates the phase of the cw signal by π . the rise time of the induced phase shift in the p cw signal is almost instantaneous and only limited by the pulse width of the p in signal , whereas the fall time of the induced phase , decays with the somewhat slower carrier recovery time . after the soa , the p cw signal is asymmetrically split between the two arms of the delay loop and recombined in the 2 × 2 coupler . the coupler directs the p cw signal into the p inv output port if the two signals in the arms are in phase , whereas it couples it into the p conv output port if the phase difference is δφ cw = π . the p cw signal on the lower arm carrying the φ cw , 1 + πphase shift first reaches the coupler and opens the switching window for the p conv output port ( right bottom inset of fig1 ). substantially 10 ps later , when the p cw , 2 signal in the upper arm reaches the coupler , the phase difference is reset and the switching window in the p conv port closes . if a second input data pulse follow , the switching window is reopened by setting the phase of the lower arm again . in an exemplary situation , ( 100 gbit / s ), the bits are introduced in intervals of 10 ps . because the delay at 10 ps equals the bit period of 100 gbit / s , a nrz format output is generated . by choosing a lower bit rate or a smaller delay loop , a rz format output can be obtained with the same device . for device characterization , rz input data signals p in were generated at a pseudo random bit sequence ( prbs ) of 2 31 − 1 at 100 bbit / s . the input signals exhibited a fwhm of ˜ 3ps and an average power of 8 dbm in the device and were chosen at a wavelength of λ 1 = 1 . 546 μm . a cw signal p cw at λ 2 = 1 . 560 μm carrying the new wavelength was externally combined with the input signal and introduced into the input port . the phase shifter and the integrated tunable coupler were set such that the bit inverted and wavelength converted signal was directed to the output port . the bit inverted signals are more advantageous for high speed since they contain all the signal pulse energy , whereas the non - inverted pulses are suppressed by the xgm that inevitably goes along with the xpm effect . a streak camera picture of the bit inverted and wavelength converted signal is depicted in fig2 ( a ). extinction rations larger than 13 db , as enabled by the integrated phase shifter and tunable coupler , are visible . both the leading and trailing pulse transients are steep . fig2 ( b ) shows eye diagrams of the 100 gbit / s signal as recorded with a 50 ghz bandwidth photodiode . the eyediagrams of the second and ninth demultiplexed signals are shown as an example in the lower left and right inset of fig2 ( b ). finally , the bit error rate ( ber ) performance is shown in fig3 . the ber of the converted 100 gbit / s signal was measured after demultiplexing back to 10 gbit / s and feeding this signal to an optically pre - amplified pin receiver . thus , the received power is measured for 10 gbit / is . various additional modifications of this invention will occur to those skilled in the art . nevertheless , all deviations from the specific teachings of this specification that basically rely upon the principles and their equivalents through which the art has been advanced are properly considered within the scope of the invention as described and claimed .