Synchronized etalon filters

Claim 3

The method of claim 1 wherein the etalon has an angular position with respect to an incident optical frequency and wherein the step of varying the effective length comprises the step of varying the angular position of the etalon with respect to the incident optical frequency.

Claim 4

The method of claim 2 wherein the step of varying the angular position of the etalon comprises: monitoring the transmission spectrum and fixing the angular position of the etalon when the amplitudes of the first and second optical reference frequencies are a maxima.

Claim 5

The method of claim 1 wherein said first and second optical frequency references are respectively provided by first and second frequency locked lasers.

Claim 6

The method of claim 4 wherein said first and second frequency locked lasers are locked to a first atomic transition in krypton occurring between 1s 2 and 2p 8 and a second atomic transition in krypton occurring between 2p 10 and 3d 3 , respectively

Claim 7

The method of claim 4 further comprising the steps of: providing a third frequency-locked laser locked to the one mode of the etalon; generating a beat spectrum between the third frequency locked laser and the first frequency locked laser; and further varying the angular position of the etalon until the beat frequency of the beat spectrum is substantially equal to zero.

Claim 8

The method of claim 1 wherein the transmission spectrum is generated by a broadband optical source.

Claim 9

A WDM optical communication system comprising: a Fabry-Perot etalon synchronized to a set of preselected optical frequencies by; providing a first optical frequency reference generating a first optical reference frequency and a second optical frequency reference generating a second optical reference frequency distinct from said first optical reference frequency; generating a transmission spectrum for an etalon having an effective length and a characteristic free spectral range that is a function of the effective length; and varying the effective length of the etalon to vary the characteristic free spectral range until the etalon generates a particular mode substantially equal to the first optical reference frequency and another mode having a minimum offset from the second optical reference frequency, said particular and another modes generated by the etalon being a preselected number of modes apart; means for generating the preselected optical frequencies; at least two optical transmitters each operating at a frequency equal to one of the preselected optical frequencies; a multiplexer for multiplexing the frequencies generated by the at least two optical transmitters; an optical transmission path for transmitting the multiplexed frequencies; a demultiplexer for demultiplexing the multiplexed frequencies; at least two receivers for receiving selected ones of the demultiplexed frequencies; and means for maintaining the optical frequencies of the optical transmitters at the preselected optical frequencies of the Fabry-Perot etalon.

Claim 10

A WDM optical communication system comprising: a Fabry-Perot etalon synchronized to a set of preselected optical frequencies by; providing a first optical frequency reference generating a first optical reference frequency and a second optical frequency reference generating a second optical reference frequency distinct from said first optical reference frequency; generating a transmission spectrum for an etalon having an effective length and a characteristic free spectral range that is a function of the effective length; and varying the effective length of the etalon to vary the characteristic free spectral range until the etalon generates a particular mode substantially equal to the first optical reference frequency and another mode having a minimum offset from the second optical reference frequency, said particular and another modes generated by the etalon being a preselected number of modes apart; means for generating the preselected optical frequencies; at least two optical transmitters each operating at a frequency equal to one of the preselected optical frequencies; a multiplexer for multiplexing the frequencies generated by the at least two optical transmitters; an optical transmission path for transmitting the multiplexed frequencies; a demultiplexer for demultiplexing the multiplexed frequencies; at least two receivers for receiving selected ones of the demultiplexed frequencies; and means for maintaining the optical frequencies of the optical transmitters at the preselected optical frequencies of the Fabry-Perot etalon.

Claim 11

The etalon of claim 8 wherein the etalon has an angular position with respect to an incident optical frequency and wherein the step of varying the effective length comprises the step of varying the angular position of the etalon with respect to the incident optical frequency.

Claim 12

The etalon of claim 9 wherein the step of varying the angular position of the etalon comprises: monitoring the transmission spectrum and fixing the angular position of the etalon when the amplitudes of the first and second optical reference frequencies are a maxima.

Claim 13

The etalon of claim 9 wherein said first and second optical frequency references are respectively provided by first and second frequency locked lasers.

Claim 14

The etalon of claim 11 wherein said first and second frequency locked lasers are locked to a first atomic transition in krypton occurring between 1s 2 and 2p 8 and a second atomic transition in krypton occurring between 2p 10 and 3d 3 , respectively.

Claim 15

The etalon of claim 12 wherein the transmission spectrum is generated by a broadband optical source.

Claim 16

The etalon of claim 11 further comprising the steps of: providing a third frequency-locked laser locked to the one mode of the etalon; generating a beat spectrum between the third frequency locked laser and the first frequency locked laser; and further varying the angular position of the etalon until the beat frequency of the beat spectrum is substantially equal to zero.

Claim 19

The method of claim 15 further comprising the step of preselecting the number of modes between said particular mode and said another mode of the etalon.

Claim 20

An etalon synchronized to a set of preselected optical frequencies by a method comprising: the steps of: providing a first optical frequency reference generating a first optical reference frequency and a second optical frequency reference generating a second optical reference frequency distinct from said first optical reference frequency; generating a transmission spectrum for an etalon having an effective length and a characteristic free spectral range that is a function of the effective length; and varying the effective length of the etalon to vary the characteristic free spectral range until the etalon generates a particular mode substantially equal to the first optical reference frequency and another mode having a minimum offset from the second optical reference frequency, said particular and another modes generated by the etalon being a preselected number of modes apart.

Claim 21

An etalon synchronized to a set of preselected optical frequencies by a method comprising: the steps of: providing a first optical frequency reference generating a first optical reference frequency and a second optical frequency reference generating a second optical reference frequency distinct from said first optical reference frequency; generating a transmission spectrum for an etalon having an effective length and a characteristic free spectral range that is a function of the effective length; and varying the effective length of the etalon to vary the characteristic free spectral range until the etalon generates a particular mode substantially equal to the first optical reference frequency and another mode having a minimum offset from the second optical reference frequency, said particular and another modes generated by the etalon being a preselected number of modes apart.

Claim 22

The etalon of claim 17 wherein the etalon has an angular position with respect to an incident optical frequency and wherein the step of varying the effective length comprises the step of varying the angular position of the etalon with respect to the incident optical frequency.

Claim 23

The etalon of claim 18 wherein the step of varying the angular position of the etalon comprises: monitoring the transmission spectrum and fixing the angular position of the etalon when the amplitudes of the first and second optical reference frequencies are a maxima.

Claim 24

The etalon of claim 17 wherein said first and second optical frequency references are respectively provided by first and second frequency locked lasers.

Claim 25

The etalon of claim 20 wherein said first and second frequency locked lasers are locked to a first atomic transition in krypton occurring between 1s 2 and 2p 8 and a second atomic transition in krypton occurring between 2p 10 and 3d 3 , respectively.

Claim 26

The etalon of claim 21 wherein the transmission spectrum is generated by a broadband optical source.

Claim 27

The etalon of claim 20 further comprising the steps of: providing a third frequency-locked laser locked to the one mode of the etalon; generating a beat spectrum between the third frequency locked laser and the first frequency locked laser; and further varying the angular position of the etalon until the beat frequency of the beat spectrum is substantially equal to zero.