Optical link

Claim 2

A link for providing a communication path for an electrical signal between an electrical signal source and an electrical signal receiver, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing modulated light; a photodetector, having an optical input port for receiving the modulated light, and having an electrical output port connected to said receiver for providing a detected electrical output signal; means for efficient coupling of the modulated light to the optical input port of the photodetector; and said optical source having a power level, and said modulator having an electrical-to-optical sensitivity in combination such that the electrical transfer efficiency between the electrical input port of said modulator and said electrical output port of said detector is greater than one.

Claim 3

A link as in claim 1 wherein the means for efficient coupling of the modulated light additionally comprises an optical fiber, having one end connected to the optical modulator output port, and the other end connected to the photodetector optical input port.

Claim 4

A link for providing a communication path for an electrical signal between an electrical signal source and an electrical signal receiver, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing modulated light; an optical fiber for carrying the modulated light; a photodetector having an optical input port for receiving the modulated light from the optical fiber, and an electrical output port for providing a detected electrical output signal to the electrical receiver; and said optical source having a power level and a sufficiently small relative intensity noise (RIN), such that the effect of the laser's relative intensity noise (RIN) at the photodetector is less than the sum of a shot noise level of the photodetector and a thermal noise presented to the photodetector by the load impedance of the electrical receiver, whereby the noise characteristics of the link are improved.

Claim 5

A link for providing a communication path for an electrical signal between an electrical signal source and an electrical signal receiver, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing modulated light; an optical fiber for carrying the modulated light; a photodetector having an optical input port for receiving the modulated light from the optical fiber, and an electrical output port for providing a detected electrical output signal to the electrical receiver; and said optical source having a power level and a sufficiently small relative intensity noise (RIN), such that the effect of the laser's relative intensity noise (RIN) at the photodetector is less than the sum of a shot noise level of the photodetector and a thermal noise presented to the photodetector by the load impedance of the electrical receiver, whereby the noise characteristics of the link are improved.

Claim 6

A link as in claim 3 wherein said optical link exhibits a transfer efficiency greater than one.

Claim 7

A link as in claim 3 wherein the optical source has a power level such that the effect of the laser's relative intensity noise (RIN) at the photodetector is less than the sum of a shot noise level of the photodetector and the lesser of a thermal noise presented to the photodetector by the load impedance of the electrical receiver and the equivalent input noise of the electrical receiver.

Claim 8

A link as in claim 3 wherein the photodetector is a positive-intrinsic-negative (PIN) photodiode.

Claim 9

A link as in claim 3 wherein the output power of the optical source is sufficient high so that the photodetector optical input power input level is greater than one milliwatt.

Claim 10

A link as in claim 3 wherein the electrical signal source is an electromagnetic field sensor.

Claim 11

A link for providing a communication path for an electrical signal between an electrical signal source and a plurality of electrical signal receivers, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; means for providing a plurality of power-divided modulated light waves at a plurality of optical output ports, each power-divided modulated light wave having a fraction of the power of the modulated light wave; a corresponding plurality of photodetectors, each photodetector having an optical input port for receiving a power-divided modulated light wave from a corresponding optical output port, and each photodetector having an electrical output port for providing a detected electrical output signal to a corresponding one of said electrical receiver; and said optical source having a relative intensity noise sufficiently low, and output optical power sufficiently high so that the sum of optical power incident at the plurality of photodetectors is such that if the same optical power level were received by a single photodetector, the effect of the laser's relative intensity noise (RIN) at the single photodetector would be less than the sum of a shot noise level of the single photodetector and a thermal noise presented to the single photodetector by the load impedance of a single electrical receiver, whereby the noise characteristics of said link are improved.

Claim 12

A link for providing a communication path for an electrical signal between an electrical signal source and a plurality of electrical signal receivers, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; means for providing a plurality of power-divided modulated light waves at a plurality of optical output ports, each power-divided modulated light wave having a fraction of the power of the modulated light wave; a corresponding plurality of photodetectors, each photodetector having an optical input port for receiving a power-divided modulated light wave from a corresponding optical output port, and each photodetector having an electrical output port for providing a detected electrical output signal to a corresponding one of said electrical receiver; and said optical source having a relative intensity noise sufficiently low, and output optical power sufficiently high so that the sum of optical power incident at the plurality of photodetectors is such that if the same optical power level were received by a single photodetector, the effect of the laser's relative intensity noise (RIN) at the single photodetector would be less than the sum of a shot noise level of the single photodetector and a thermal noise presented to the single photodetector by the load impedance of a single electrical receiver, whereby the noise characteristics of said link are improved.

Claim 13

A link for providing a communication path for an electrical signal between an electrical signal source and a plurality of electrical signal receivers, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; means for providing a plurality of power-divided modulated light waves at a plurality of optical output ports, each power-divided modulated light wave having a fraction of the power of the modulated light wave; a corresponding plurality of photodetectors, each photodetector having an optical input port for receiving a power-divided modulated light wave from a corresponding optical output port, and each photodetector having an electrical output port for providing a detected electrical output signal to a corresponding electrical receiver; and said optical source having an output optical power and said modulator having an electrical-to-optical sensitivity in combination such that an electrical transfer efficiency defined as the sum of the electrical power at the electrical output ports of said photodetectors divided by the electrical power at said electrical input port of said modulator is greater than one.

Claim 14

A link for providing a communication path for an electrical signal between an electrical signal source and a plurality of electrical signal receivers, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; means for providing a plurality of power-divided modulated light waves at a plurality of optical output ports, each power-divided modulated light wave having a fraction of the power of the modulated light wave; a corresponding plurality of photodetectors, each photodetector having an optical input port for receiving a power-divided modulated light wave from a corresponding optical output port, and each photodetector having an electrical output port for providing a detected electrical output signal to a corresponding electrical receiver; and said optical source having an output optical power and said modulator having an electrical-to-optical sensitivity in combination such that an electrical transfer efficiency defined as the sum of the electrical power at the electrical output ports of said photodetectors divided by the electrical power at said electrical input port of said modulator is greater than one.

Claim 15

A link for providing a communication path for an electrical signal between an electrical signal source and a plurality of electrical signal receivers, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; means for providing a plurality of power-divided modulated light waves at a plurality of optical output ports, each power-divided modulated light wave having a fraction of the power of modulated light wave; a corresponding plurality of photodetectors, each photodetector having an optical input port for receiving a power-divided modulated light wave from a corresponding optical output port, and each photodetector having an electrical output port for providing a detected electrical output signal to a corresponding electrical receiver; and said optical source having an output power so that the ratio of optical power in the modulated optical wave to input electrical power available from the electrical source is sufficiently high so that shot noise limited performance is observed in an equivalent single photodetector that receives the same input power as the sum of the optical powers incident on the plurality of photodetectors, whereby the noise characteristics of said link are improved.

Claim 16

A link for providing a communication path for an electrical signal between an electrical signal source and a plurality of electrical signal receivers, the link comprising: an optical source for providing light; an optical modulator having an optical input port for receiving light from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; means for providing a plurality of power-divided modulated light waves at a plurality of optical output ports, each power-divided modulated light wave having a fraction of the power of modulated light wave; a corresponding plurality of photodetectors, each photodetector having an optical input port for receiving a power-divided modulated light wave from a corresponding optical output port, and each photodetector having an electrical output port for providing a detected electrical output signal to a corresponding electrical receiver; and said optical source having an output power so that the ratio of optical power in the modulated optical wave to input electrical power available from the electrical source is sufficiently high so that shot noise limited performance is observed in an equivalent single photodetector that receives the same input power as the sum of the optical powers incident on the plurality of photodetectors, whereby the noise characteristics of said link are improved.

Claim 17

A link for providing a communication path for an electrical signal between an electrical signal souce and an electrical signal receiver, the link comprising: a laser having low relative intensity noise (RIN) for providing a high-powered light wave; an optical modulator having an optical input port for receiving the light wave from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; a photodetector having an optical input port for receiving the modulated light wave from the optical modulator, and an electrical output port for providing a detected electrical output signal to the electrical receiver; and said optical source having a power level, such that the equivalent noise of the laser's (RIN) at the photodetector is less than the sum of a shot noise level of the photodetector and a noise level presented to the photodetector by the load impedance of the electrical receiver, whereby the noise characteristics of said link are improved.

Claim 18

A link for providing a communication path for an electrical signal between an electrical signal souce and an electrical signal receiver, the link comprising: a laser having low relative intensity noise (RIN) for providing a high-powered light wave; an optical modulator having an optical input port for receiving the light wave from the optical source, an electrical input port for receiving the electrical signal from the electrical signal source, and an optical modulator output port for providing a modulated light wave; an optical fiber for carrying the modulated light wave; a photodetector having an optical input port for receiving the modulated light wave from the optical modulator, and an electrical output port for providing a detected electrical output signal to the electrical receiver; and said optical source having a power level, such that the equivalent noise of the laser's (RIN) at the photodetector is less than the sum of a shot noise level of the photodetector and a noise level presented to the photodetector by the load impedance of the electrical receiver, whereby the noise characteristics of said link are improved.

Claim 19

A link as in claim 12 wherein the laser emits a light wave having a wavelength of about 1.3 microns.

Claim 20

A link as in claim 12 wherein the laser RIN is less than -165 dB/Hz.

Claim 21

A link as in claim 12 wherein the laser is a neodymium yttrium aluminum garnet (Nd:YAG) laser.