Multi-wavelength laser source

A multi-wavelength light source for producing laser light having a plurality of wavelengths, comprising:

• a laser having a continuous wave light output;
• a source of periodic electromagnetic signals having a signal output having a characteristic repetition rate;
• a Mach-Zender optical modulator generating an amplitude modulated optical signal, having a light input coupled to the light output of the laser, a modulating input coupled to the signal output of the source, and a light output, such that the light output of the optical modulator comprises the light from the light input, modulated by the output of the source introduced at the modulating input;
• and
• a non-linear element having a light input coupled to the light output of the optical modulator and a light output;
• such that the light output of the non-linear element comprises a plurality of optical signals, spaced apart by a wavelength related to the characteristic repetition rate of the source;
• in which the peak-to-peak phase modulation induced in each arm of the Mach-Zender modulator is between 4.2 and 4.8 radians.

A multi-wavelength light source for producing laser light having a plurality of wavelengths, comprising:

• a laser having a continuous wave light output:
• a source of periodic electromagnetic signals having a signal output having a characteristic repetition rate;
• a Mach-Zender optical modulator generating an amplitude modulated optical signal, having a light input coupled to the light output of the laser, a modulating input coupled to the signal output of the source, and a light output, such that the light output of the optical modulator comprises the light from the light input, modulated by the output of the source introduced at the modulating input;
• and
• a non-linear element having a light input coupled to the light output of the optical modulator and a light output;
• such that the light output of the non-linear element comprises a plurality of optical signals, spaced apart by a wavelength related to the characteristic repetition rate of the source;
• in which the Mach-Zehnder modulator is biased at a maximum on its switching characteristic.

A multi-wavelength light source for producing laser light having a plurality of wavelengths, comprising:

• a laser having a continuous wave light output;
• a source of periodic electromagnetic signals having a signal output having a characteristic repetition rate;
• a Mach-Zender optical modulator generating an amplitude modulated optical signal, having a light input coupled to the light output of the laser, a modulating input coupled to the signal output of the source, and a light output, such that the light output of the optical modulator comprises the light from the light input, modulated by the output of the source introduced at the modulating input;
• and
• a non-linear element having a light input coupled to the light output of the optical modulator and a light output;
• such that the light output of the non-linear element comprises a plurality of optical signals, spaced apart by a wavelength related to the characteristic repetition rate of the source;
• in which the two arms of the the Mach-Zehnder modulator are driven sinusoidally such that a sinusoidal phase modulation of about 4.2 to 4.8 radians peak-to peak magnitude and of opposite polarity is induced each arm of the modulator.

A multi-wavelength light source for producing laser light having a plurality of wavelengths, comprising:

• a laser having a continuous wave light output;
• a source of periodic electromagnetic signals having a signal output having a characteristic repetition rate;
• a directional coupler amplitude modulator, having a light input coupled to the light output of the laser, a modulating input coupled to the signal output of the source, and a light output, such that the light output of the optical modulator comprises the light from the light input, modulated by the output of the source introduced at the modulating input;
• and
• a non-linear element having a light input coupled to the light output of the modulator and a light output;
• such that the light output of the non-linear element comprises a plurality of optical signals, spaced apart by a wavelength related to the characteristic repetition rate of the source.

A multi-wavelength light source for producing laser light having a plurality of wavelengths, comprising:

• a laser having a continuous wave light output;
• a source of periodic electromagnetic signals having a signal output having a characteristic repetition rate;
• an optical modulator having a light input coupled to the light output of the laser, a modulating input coupled to the signal output of the source, and a light output, such that the light output of the optical modulator comprises the light from the light input, modulated by the output of the source introduced at the modulating input;
• in which the optical modulator comprises:
• a phase modulator having a light input, a modulation input, and a light output, the light input forming the light input of the optical modulator, the modulation input comprising the modulating input of the optical modulator, the light signal at the light output comprising the light from the light input phase modulated by the signal from the modulating input;
• a length of dispersive fiber, having a first end coupled to the light output of the phase modulator and a second end comprising the light output of the optical modulator;
• such that the phase modulated light output of the phase modulator is converted to a periodic amplitude modulated optical signal by the dispersive fiber;
• and
• a non-linear element having a light input coupled to the light output of the optical modulator and a light output;
• such that the light output of the non-linear element comprises a plurality of optical signals, spaced apart by a wavelength related to the characteristic repetition rate of the source.

A method of producing a plurality of light signals of spaced-apart wavelength, the wavelength being related to the frequency of a periodic signal, comprising the steps of:

• producing a single wavelength of coherent light in a continuous-wave laser;
• modulating the light in an optical modulator with a periodic electromagnetic signal;
• introducing the modulated light into a non-linear element, such that the modulated light generates higher-order spectral components through non-linear effects in the non-linear element;
• supplying the multi-wavelength light output from the non-linear element into a plurality of band-pass filters, each band-pass filter being tuned to one of the plurality of wavelengths of light;
• modulating the output of each of the plurality of band-pass filters in an optical modulator with a channel of data.

A method of producing a plurality of light signals of spaced-apart wavelength, the wavelength being related to the frequency of a periodic signal, comprising the steps of:

• producing a single wavelength of coherent light in a continuous-wave laser;
• modulating the light in an optical modulator with a periodic electromagnetic signal;
• introducing the modulated light into a non-linear element, such that the modulated light generates higher-order spectral components through non-linear effects in the non-linear element;
• supplying the multi-wavelength light output from the non-linear element into a wavelength demultiplexer having a plurality of outputs, each output being tuned to one of the plurality of wavelengths of light;
• and
• modulating each of the plurality of outputs of the wavelength demultiplexer in an optical modulator with a channel of data.

A wavelength division multiplex transmitter comprising:

• a multi-wavelength source having a light output comprising a plurality of light signals of a plurality of wavelengths, the multi-wavelength source comprising:
• a laser having a continuous wave light output;
• a source of periodic electromagnetic signals having a signal output having a characteristic repetition rate;
• an optical modulator having a light input coupled to the light output of the laser, a modulating input coupled to the signal output of the source, and a light output, such that the light output of the optical modulator comprises the light from the light input, modulated by the output of the source introduced at the modulating input;
• and
• a non-linear element having a light input coupled to the light output of the optical modulator and a light output;
• such that the light output of the non-linear element comprises a plurality of optical signals, spaced apart by a wavelength related to the characteristic repetition rate of the source;
• wavelength-separation means for separating an optical signal into a plurality of outputs based on the wavelength of the signal components, having an input coupled to the output of the multi-wavelength source, and a plurality of light outputs each comprising light having a wavelength, the wavelengths being chosen from the plurality of wavelengths of light in the light output of the multi-wavelength source;
• and
• a plurality of single-channel modulators, each comprising:
• an optical modulator having an input coupled to a light output of the wavelength separation means, a modulation input, and a light output, the light output comprising the light present at the light input modulated by the data on the modulation input, the output of the optical modulator being the output of the single channel modulator.