Electro-optic modulator with continuously adjustable chirp

An electro-optic modulator for generating an output optical signal having an adjustable chirp from at least one input optical signal, the electro-optic modulator comprising:

• optical signal splitting means for splitting the at least one input optical signal into a first optical signal, a second optical signal, and N optical signals, the optical signal splitting means having at least one splitting variable coupler having an adjustable coupling ratio for adjusting a power ratio of the first optical signal to the second optical signal;
• a first optical phase modulator for phase modulating the first optical signal as a function of a first phase function of time, the first phase function of time having a first time derivative;
• a second optical phase modulator for phase modulating the second optical signal as a function of a second phase function of time, the second phase function of time having a first time derivative which is the negative of the first time derivative of the first phase function of time;
• and
• optical signal combining means for combining the first optical signal, a first portion of the N optical signals, the second optical signal, and a second portion of the N optical signals, generating an output optical signal, the optical signal combining means having at least one combining variable coupler having a coupling ratio equal to the adjustable coupling ratio for combining the first and second optical signals according to the adjustable coupling ratio, wherein the power and phase of the first portion of the N optical signals are such that when combined with the first optical signal an amplitude modulated optical signal with a positive chirp results, and wherein the power and phase of the second portion of the N optical signals are such that when combined with the second optical signal an amplitude modulated optical signal with a negative chirp results;
• whereby the adjustable coupling ratio determines a magnitude and a sign of the adjustable chirp of the output optical signal.

An electro-optic modulator for applying an adjustable chirp to at least one input optical signal, the electro-optic modulator comprising:

• optical signal splitting means for splitting according to an adjustable coupling ratio the at least one input optical signal into a first optical signal and a second optical signal;
• a first optical phase modulator for phase modulating as a function of a first phase function of time the first optical signal, the first phase function of time having a first time derivative;
• a second optical phase modulator for phase modulating as a function of a second phase function of time the second optical signal, the second phase function of time having a first time derivative which is the negative of the first time derivative of the first phase function of time;
• and
• optical signal combining means for combining according to the adjustable coupling ratio the first optical signal and the second optical signal after they have been modulated, generating an output optical signal;
• whereby the adjustable coupling ratio determines a magnitude and a sign of the adjustable chirp applied to the at least one input optical signal to generate the output optical signal.

A method of generating an output optical signal having an adjustable chirp from at least one input optical signal, the method comprising:

• splitting according to an adjustable coupling ratio the at least one input optical signal into a first optical signal and a second optical signal;
• amplitude modulating the first optical signal with a positive chirp, generating a positively chirped optical signal;
• amplitude modulating the second optical signal with a negative chirp, generating a negatively chirped optical signal;
• and
• combining according to the adjustable coupling ratio the positively chirped optical signal and the negatively chirped optical signal, generating an output optical signal;
• whereby the adjustable coupling ratio determines a magnitude and a sign of the adjustable chirp of the output optical signal.

A method of generating an output optical signal having an adjustable chirp from at least one input optical signal, the method comprising:

• splitting the at least one input optical signal into a first optical signal, a second optical signal, and N optical signals;
• adjusting a power ratio of the first optical signal to the second optical signal according to an adjustable coupling ratio;
• phase modulating the first optical signal as a function of a first phase function of time, the first phase function of time having a first time derivative;
• phase modulating the second optical signal as a function of a second phase function of time, the second phase function of time having a first time derivative which is the negative of the first time derivative of the first phase function of time;
• and
• combining the first optical signal, a first portion of the N optical signals, the second optical signal, and a second portion of the N optical signals, wherein the first and second optical signals are combined according to the adjustable coupling ratio, generating an output optical signal, wherein the power and phase of the first portion of the N optical signals are such that when combined with the first optical signal an amplitude modulated optical signal with a positive chirp results, and wherein the power and phase of the second portion of the N optical signals are such that when combined with the second optical signal an amplitude modulated optical signal with a negative chirp results, and wherein the amplitude modulated signal with a negative chirp and the amplitude modulated signal with a positive chirp constructively interfere when they are combined;
• whereby the adjustable coupling ratio determines a magnitude and a sign of the adjustable chirp of the output optical signal.

A method of applying an adjustable chirp to at least one input optical signal, the method comprising:

• splitting according to an adjustable coupling ratio the at least one input optical signal into a first optical signal and a second optical signal;
• phase modulating as a function of a first phase function of time the first optical signal, the first phase function of time having a first time derivative;
• phase modulating as a function of a second phase function of time the second optical signal, the second phase function of time having a first time derivative which is the negative of the first time derivative of the first phase function of time;
• and
• combining according to the adjustable coupling ratio the first optical signal and the second optical signal after they have been modulated, generating an output optical signal;
• whereby the adjustable coupling ratio determines a magnitude and a sign of the adjustable chirp applied to the at least one input optical signal to generate the output optical signal.