High efficiency optical feedback modulator and method of operation

A high efficiency optical feedback modulator comprising:

• an optical modulator having at least two optical inputs and at least two optical outputs, an input light beam being receivable on at least one of the optical inputs;
• and
• an optical feedback system configured to feed an optical feedback signal from at least one of the optical outputs to at least one of the optical inputs, the optical feedback system including an optical amplifier disposed between said at least one of the optical outputs and said at least one of the optical inputs, the optical amplifier being operable to increase an optical intensity of the optical feedback signal;
• said optical modulator including a first optical coupler wherein the input light beam is combined with the optical feedback signal to produce first and second optical signals;
• said optical modulator being operable to modulate the first and second optical signals in response to an electrical signal to produce first and second phase shifted optical signals, the electrical signal being applied around a selected phase angle operating point of the optical modulator within a specified range of phase angles wherein a slope of a transfer curve relating relative optical intensity of an optical signal output by the optical modulator versus phase angle of the optical modulator is at least 0.08725 per degree;
• said optical modulator including a second optical coupler wherein the first phase shifted optical signal is combined with the second phased shifted optical signal to produce the optical feedback signal and a high modulation depth optical signal.

A fiber optic system comprising:

• a high efficiency optical feedback modulator operable to receive an electronic input signal;
• an optic fiber coupled to an optical output of the optical modulator and operable to communicate a high modulation depth optical signal;
• and
• an optical receiver operable to receive the high modulation depth optical signal and convert the high modulation depth optical signal into an electronic output signal;
• said high efficiency optical feedback modulator including an optical modulator having at least two optical inputs and at least two optical outputs and an optical feedback system feeding an optical feedback signal from at least one of the optical outputs to at least one of the optical inputs, said optical feedback system comprising an optical amplifier disposed between said at least one of the optical outputs and said at least one of the optical inputs, the optical amplifier being operable to increase an optical intensity of the optical feedback signal, said optical modulator being operable to receive an input light beam on at least one of the optical inputs, combine the optical feedback signal with the input light beam, and modulate the combined input light beam and optical feedback signal in response to the electronic input signal applied around a selected phase angle operating point of the optical modulator within a specified range of phase angles wherein a slope of a transfer curve relating relative optical intensity of an optical signal output by the optical modulator versus phase angle of the optical modulator is at least 0.08725 per degree to produce the high modulation depth optical signal.

A method for producing a high modulation depth optical signal comprising:

• communicating an input light beam to a first optical input of an optical modulator;
• communicating an optical feedback signal from a second optical output of the optical modulator to a second optical input of the optical modulator, wherein an optical intensity of the optical feedback signal is amplified prior to communicating the optical feedback signal to the second optical input of the optical modulator;
• coupling the input light beam with the optical feedback signal to produce a first and a second optical signal;
• intensity modulating at least one of the optical signals in response to an electronic input signal applied to the optical modulator to produce a first and a second phase shift optical signal, the electronic input signal being applied around a selected phase angle operating point of the optical modulator within a specified range of phase angles wherein a slope of a transfer curve relating relative optical intensity of an optical signal output by the optical modulator versus phase angle of the optical modulator is at least 0.08725 per degree;
• and
• coupling the phase shift optical signals to produce the high modulation depth optical signal and the optical feedback signal.

A high efficiency optical feedback modulator comprising:

• an optical modulator having at least two optical inputs and at least two optical outputs;
• and
• an optical feedback system coupling at least one of the optical outputs to at least one of the optical inputs, the optical feedback system including an optical amplifier disposed between said at least one of the optical outputs and said at least one of the optical inputs, the optical amplifier being operable to increase an optical intensity of the optical feedback signal;
• wherein the optical modulator comprises a Mach-Zehnder two-by-two optical modulator comprising a first and second optical input, and a first optical output that is the complement of a second optical output, and wherein the feedback system couples the second optical output to the second optical input;
• and
• wherein the optical modulator modulates an input light beam received on the first optical input and an optical feedback signal received on the second optical input in response to an electronic input signal applied around a selected phase angle operating point of the optical modulator within a specified range of phase angles wherein a slope of a transfer curve relating relative optical intensity of an optical signal output by the optical modulator versus phase angle of the optical modulator is at least 0.08725 per degree to output a high modulation depth optical signal.