Non-linear optical amplification

Claim 5

A method as in claim 1 or 2, wherein the input optical signal is tuned to a peak of a Fabry-Perot mode in the gain spectrum for the device.

Claim 6

A method as in claim 1 or 2 wherein the device comprises an input facet through which the optical signal is input into said amplification region, the device including means to reduce the reflectivity of that facet.

Claim 7

A method as claimed in claim 4 wherein said input facet reflectivity is 20% or less.

Claim 8

A method as claimed in claim 5 wherein said input facet reflectivity is 10% or less.

Claim 9

A method as claimed in claim 6 wherein said input facet reflectivity is 3% or less.

Claim 10

A method as claimed in claim 7 wherein said input facet reflectivity is 1% or less.

Claim 11

A method as in claim 1 or 2 wherein an output facet is provided for the outputting of said amplified output, the device including means to reduce the reflectivity of the output facet.

Claim 12

A method as claimed in claim 9 where the reflectivity of said output facet is 20% or less.

Claim 13

A method as claimed in claim 10 where the reflectivity of said output facet is 10% or less.

Claim 14

A method as claimed in claim 11 where the reflectivity of said output facet is 3% or less.

Claim 15

A method as claimed in claim 12 where the reflectivity of said output facet is 1% or less.

Claim 16

A method as in claim 4 wherein said input facet has substantially the same reflectivity as said output facet.

Claim 17

A method as in claim 4 wherein said input and output facets have substantially different reflectivities.

Claim 18

A method as in claim 1 or 2, wherein said controlling step comprises controlling the temperature of the device, and/or the bias of the amplifier region.

Claim 19

A method as in claim 1 or 2 including varying the input wavelength so as to control the output wavelength.

Claim 20

A method as in claim 1 or 2 further including controlling the device so as to operate bistably.

Claim 21

A method as in claim 1 or 2 where the device is controlled so as to operate non-linearly, but not bistably.

Claim 22

A wavelength controlled optical switch operated according to a method as claimed in any preceding claim, wherein the device is controlled so as to operate bistably.

Claim 23

A regenerative amplifier operated according to claim 19.

Claim 24

An optical amplifier of the type having a lasing threshold and partially reflective facets, the amplifier including a single saturable absorption region and being adapted to operate non-linearly below the lasing threshold so that for an optical signal at wavelength λ i input to the device an amplified output at wavelength λ i is generated.

Claim 25

An optical amplifier of the type having a lasing threshold and partially reflective facets, the amplifier including a single saturable absorption region and being adapted to operate non-linearly below the lasing threshold so that for an optical signal at wavelength λ i input to the device an amplified output at wavelength λ i is generated.

Claim 26

An optical amplifier as claimed in claim 22, wherein a first electrode is provided for the biasing of an amplifying portion of the device, a second electrode is provided for the biasing of said saturable absorption region, and wherein the electrical resistance between said first and second electrodes is sufficiently high to enable said amplifying portion and said saturable absorption region to be differentially biassed with a substantially lower voltage applied to said second electrode than to said first electrode.

Claim 27

An optical amplifier according to claim 1 or 2, suitable for pulse compression.

Claim 28

An optical amplifier according to claim 1 or 2 suitable for low noise amplification.

Claim 29

A method as in claim 9 wherein said input facet has substantially the same reflectivity as said output facet.

Claim 30

A method as in claim 9 wherein said input and output facets have substantially different reflectivities.

Claim 31

An optical amplifier comprising: a buried heterostructure solid state diode having a light signal passage channel and having first and second electrodes spaced apart by at least approximately 10 μm longitudinally along and above said channel for applying different electrical bias currents to the diode at respectively located spaced-apart regions, thus defining a corresponding optical amplifier region under the first electrode and a saturable optical absorber region under the second electrode; said diode having partially reflective facets of substantially less than 30% reflectivity located at opposite ends of said channel between which facets said first and second electrodes are sequentially disposed; said first electrode being biassed to a first level sufficiently below the lasing threshold of said diode as to remain therebelow even when an input light signal pulse is received via one of said facets and causing the corresponding amplifier region of the diode to operate as a non-linear light amplifier; said second electrode being conditioned to cause the saturable light absorber region to act as a saturable light absorber when receiving light signals output from said amplifier region just prior to outputting a processed light signal via the remaining one of said facets.

Claim 32

An optical amplifier comprising: a buried heterostructure solid state diode having a light signal passage channel and having first and second electrodes spaced apart by at least approximately 10 μm longitudinally along and above said channel for applying different electrical bias currents to the diode at respectively located spaced-apart regions, thus defining a corresponding optical amplifier region under the first electrode and a saturable optical absorber region under the second electrode; said diode having partially reflective facets of substantially less than 30% reflectivity located at opposite ends of said channel between which facets said first and second electrodes are sequentially disposed; said first electrode being biassed to a first level sufficiently below the lasing threshold of said diode as to remain therebelow even when an input light signal pulse is received via one of said facets and causing the corresponding amplifier region of the diode to operate as a non-linear light amplifier; said second electrode being conditioned to cause the saturable light absorber region to act as a saturable light absorber when receiving light signals output from said amplifier region just prior to outputting a processed light signal via the remaining one of said facets.

Claim 33

An optical amplifier as in claim 28 wherein said first electrode is at least approximately twice as long as said second electrode along said channel.

Claim 34

An optical amplifier as in claim 28 wherein there are no electrodes in addition to said first and second electrodes between said facets.

Claim 35

An optical amplifier as in claim 28 wherein said facets have reflectivities of substantially less than 10%.

Claim 36

An optical amplifier as in claim 31 wherein one facet has a substantially higher reflectivity than the other facet.

Claim 37

An optical amplifier as in claim 28 including means for controlling the wavelength of input light signals to correspond to a lasing mode of said diode if biassed above its lasing threshold.

Claim 38

An optical amplifier as in claim 28 wherein said electrodes are biassed to cause bistable optical outputs from said amplifier.