Amplifier Enhanced Optical Signal Spectrum Filtering Method and System

1 . A method of filtering a broadband optical signal comprising:

(a) outputting a broadband optical signal;

(b) filtering the broadband optical signal a plurality of times;

(c) optically amplifying the broadband optical signal; and

(d) providing the filtered and amplified broadband optical signal to an optical receiving device.

2 . The method of claim 1 , wherein step (c) includes, optically amplifying the broadband optical signal after the plurality of times in step (b).

3 . The method of claim 1 , wherein step (c) includes, optically amplifying the broadband optical signal between a pair of the plurality of times in step (b).

4 . The method of claim 1 , wherein step (b) includes, filtering the broadband optical signal with the same filtering function each of the plurality of times.

5 . The method of claim 1 , wherein:

step (b) includes, filtering the broadband optical signal a first plurality of times using a first filtering function each time; and

step (c) includes optically amplifying the broadband optical signal between one pair of the first plurality of times.

6 . The method of claim 5 , wherein step (b) further includes:

filtering the broadband optical signal a second plurality of times using a second filtering function each time; and

step (c) includes optically amplifying the broadband optical signal between one pair of the second plurality of times.

7 . The method of claim 6 , wherein:

the first filtering function comprises phase and amplitude filtering; and

the second filtering function comprises amplitude only filtering.

8 . The method of claim 6 , wherein:

the first filtering function is performed by a first wavelength selective switch; and

the second filtering function is performed by a second wavelength selective switch.

9 . A method of filtering a broadband optical signal comprising:

(a) causing a broadband optical signal to pass multiple times through a first wavelength selective switch (WSS 1 );

(b) between at least one pair of passes of the broadband optical signal through the WSS 1 in step (a), amplifying the broadband optical signal;

(c) following steps (a) and (b), causing the broadband optical signal to pass multiple times through a second wavelength selective switch (WSS 2 ); and

(d) between at least one pair of passes of the broadband optical signal through the WSS 2 in step (c), amplifying the broadband optical signal.

10 . The method of claim 9 , wherein at least one of the following:

the WSS1 is programmed, operative, and/or configured to perform spectral shaping or filtering of the broadband optical signal using phase and amplitude filtering; and

the WSS2 is programmed, operative, and/or configured to perform spectral shaping or filtering of the broadband optical signal using amplitude only filtering.

11 . The method of claim 9 , wherein, following step (d), the broadband optical signal has a shape of a bandpass filtered signal.

12 . The method of claim 9 , further including:

(e) following steps (c) and (d), outputting the broadband optical signal to an optical receiving device.

13 . The method of claim 9 , wherein steps (a) and (b) comprise:

(1) causing the broadband optical signal to pass two times through the WSS 1 ;

(2) following step (1), amplifying the broadband optical signal; and

(3) following step (2), causing the broadband optical signal to pass at least one more time through the WSS 1 .

14 . The method of claim 13 , wherein steps (c) and (d) comprise:

(1) causing the broadband optical signal to pass two times through the WSS 2 ;

(2) following step (1), amplifying the broadband optical signal; and

(3) following step (2), causing the broadband optical signal to pass at least one more time through the WSS 2 .

15 . A broadband optical signal filtering system comprising first and second optical amplifiers and first and second wavelength selective switches (WSS 1 and WSS 2 ) connected whereupon, a broadband optical signal passes through the broadband optical signal filtering system in the following order:

(a) through the WSS 1 at least one time;

(b) through the first optical amplifier;

(c) through the WSS 1 at least once more;

(d) through the WSS 2 at least one time;

(e) through the second optical amplifier; and

(f) through the WSS 2 at least once more.

16 . The broadband optical signal filtering system of claim 15 , wherein at least one of the following:

the WSS1 is programmed, operative, and/or configured to perform spectral shaping or filtering of each pass of the broadband optical signal through the WSS1 using phase and amplitude filtering; and

the WSS2 is programmed, operative and/or configured to perform spectral shaping or filtering of each pass of the broadband optical signal through the WSS2 using amplitude only filtering.

17 . The broadband optical signal filtering system of claim 16 , wherein:

the WSS1 performs the same spectral shaping or filtering of each pass of the broadband optical signal through the WSS 1 ; and

the WSS2 performs the same spectral shaping or filtering of each pass of the broadband optical signal through the WSS 2 .

18 . The broadband optical signal filtering system of claim 15 , further including at least one of the following:

a broadband optical signal source outputting the broadband optical signal to the WSS 1 prior to step (a); and

an optical receiving device coupled to receive the broadband optical signal from the WSS 2 following step (f).

19 . The broadband optical signal filtering system of claim 15 , wherein at least one of the following:

step (a) includes the broadband optical signal passing through the WSS 1 twice;

step (c) includes the broadband optical signal passing through the WSS 1 twice; and

step (d) includes the broadband optical signal passing through the WSS 2 twice.