Third-order optical autocorrelator for time-domain operation at the telecommunication wavelengths

A method for measuring an optical pulse, comprising:

• receiving the optical pulse of a wavelength of λ from a source;
• dividing the optical pulse into two parts to produce a time delay between each part;
• combining the two parts of the optical pulse in a material including a molecule having a formula D-Π-A, where D is an electron donor group, A is an electron acceptor group, and Π is a conjugated structure having π bonds that connect the D donor group to the A acceptor group, said molecule exhibiting an absorption band at a wavelength λ0 and exhibiting a weakly absorbing region as compared to the absorption band at λ0 at a wavelength λ1, such that λ1<λ0 that λ/2 has a value of about λ0 and that λ/3 has a value of about λ1;
• measuring a third harmonic signal at λ/3 as a function of the time delay between the two parts of the optical pulse;
• extracting from said third harmonic signal as a function of the time delay at least one of a pulse width and a pulse shape correlated with the optical pulse.

A device for producing a third harmonic signal from an optical pulse of wavelength λ, comprising:

• a material including a molecule, having a formula D-Π-A, where D is an electron donor group, A is an electron acceptor group, and Π is a conjugated structure having π bonds that connect the D donor group to the A acceptor group, said molecule exhibiting a strong absorption band centered at a wavelength λ0 and exhibiting a weakly absorbing region as compared to the absorption band at λ0 at a wavelength λ1 such that λ1<λ0;
• a divider configured to receive the optical pulse from a source and divide the pulse into two parts to produce a time delay between each part;
• a combiner configured to combine the two parts of the optical pulse having said time delay;
• and
• an optical element configured to couple the time-delayed and combined two parts into the material to thereby generate the third harmonic signal.

A device for measuring an optical pulse at a wavelength λ, comprising:

• a divider configured to receive the optical pulse from a source and divide the pulse into two parts to produce a time delay between each part;
• a combiner configured to combine the two parts of the optical pulse having said time delay;
• a material receiving said two parts of the optical pulse, said material comprising at least one molecule having a formula D-Π-A, where D is an electron donor group, A is an electron acceptor group, and Π is a conjugated structure having π bonds that connect D to A, said molecule exhibiting a strong absorption band centered at a wavelength λ0 and exhibiting a weakly absorbing region as compared to the absorption band at λ0 at a wavelength λ1, such that λ1<λ0, that λ/2 has a value of about λ0, and that λ/3 has a value of about λ1;
• a detector configured to measure a third harmonic signal at λ/3 as a function of the time delay between the two parts of the optical pulse;
• and
• an extractor configured to extract, from said third harmonic signal as a function of the time delay, at least one of a pulse width and a pulse shape correlated with the optical pulse.