Optical fiber amplifier using synchronized etalon filter

• US 6,181,467 B1
• Filed: 12/10/1998
• Issued: 01/30/2001
• Est. Priority Date: 12/10/1997
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Chel-Han, Jung, Yun-Chel
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US09/208,850
• Time in Patent Office: 782 Days
• Field of Search: 359/341, 359/124
• US Class Current: 359/341.31
• CPC Class Codes: H01S 2301/02 ASE (amplified spontaneous emission), noise; Reduction thereof
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/06787 Bidirectional amplifier
• CPC Class Codes: H01S 3/1608 erbium
• CPC Class Codes: H04B 10/291 in which processing or amplification is carried out without conversion of the main signal from optical form

Abstract

A multi-stage optical fiber amplifier having a high gain, a high output power and a low noise figure, without limiting a gain bandwidth includes at least two stages of cascade connected optical fiber amplifiers. A synchronized etalon filter is disposed between the optical fiber amplifiers. The etalon filter has a resonant frequency matched with a standard frequency of a WDM (Wavelength Division Multiplexing) system using the optical fiber amplifiers.

Claims

1. A multi-stage optical fiber amplifier comprising:

at least two stages of cascade connected optical fiber amplifiers; and

a synchronized etalon filter disposed between the at least two stages of optical fiber amplifiers, said etalon filter having a front end comprising an optical isolator, said isolator adapted for removing backward-traveling ASE noise and for suppressing reflection by the filter.

2. A multi-stage optical fiber amplifier comprising:

at least two stages of cascade connected optical fiber amplifiers; and

a synchronized etalon filter disposed between the at least two stages of optical fiber amplifiers, said etalon filter having a resonant frequency matched with a standard frequency of a WDM (Wavelength Division Modulation) system using the at least two stages of optical fiber amplifiers.

3. A two-stage optical fiber amplifier comprising:

a first optical isolator coupled to an input optical signal;

a first WDM coupler for WDM coupling an optical signal output from the first optical isolator to a pump laser;

a first erbium-doped fiber amplifier (EDFA) for amplifying an output signal of the first WDM coupler;

a second optical isolator coupled to an output of the first EDFA;

a synchronized etalon filter for passing a wavelength division multiplexed signal output from the second optical isolator and for eliminating amplified spontaneous emission (ASE) noise;

a second WDM coupler for WDM coupling an optical signal output from the synchronized etalon filter to a pump laser;

a second EDFA for amplifying an output signal of the second WDM coupler; and

a third optical isolator coupled to an output of the second EDFA.

4. A bidirectional optical fiber amplifier comprising:

first and second optical fiber amplifiers for respectively amplifying first and second optical signals traveling in opposite directions, the first and second optical signals having different frequencies;

first and second optical circulators coupled between the first and second optical fiber amplifiers, for separating a first path for the first optical signal from a second path for the second optical signal; and

first and second etalon filters respectively disposed in the first and second paths, for selectively passing an optical signal traveling in one direction and removing an optical signal traveling in another direction.

5. A method of manufacturing a multi-stage optical fiber amplifier comprising the steps of:

(1) providing at least two stages of cascade connected optical fiber amplifiers; and

(2) disposing a synchronized etalon filter between the at least two stages of optical fiber amplifiers, said etalon filter having a front end comprising an optical isolator, said isolator adapted for removing backward-traveling ASE noise and for suppressing reflection by the filter.

6. A method of manufacturing a multi-stage optical fiber amplifier comprising the steps of:

(1) providing at least two stages of cascade connected optical fiber amplifiers; and

(2) disposing a synchronized etalon filter between the at least two stages of optical fiber amplifiers; and

(3) providing said etalon filter with a resonant frequency matched with a standard frequency of a WDM (wavelength division modulation) system using the at least two stages of optical fiber amplifiers.

7. A method of manufacturing a two-stage optical fiber amplifier comprising the steps of:

(1) coupling an input optical signal to a first optical isolator;

(2) coupling an optical signal output from the first optical isolator to a pump laser with a first WDM coupler;

(3) providing a first amplifier stage for amplifying an output signal of the first WDM coupler with a first erbium-doped fiber amplifier (EDFA);

(4) coupling an output of the first EDFA to a second optical isolator;

(5) coupling a synchronized etalon filter to an output from the second optical isolator for passing a wavelength division multiplexed signal and for eliminating amplified spontaneous emission (ASE) noise;

(6) coupling an optical signal output from the synchronized etalon filter to a pump laser with a second WDM coupler;

(7) providing a second amplifier stage for amplifying an output signal of the second WDM coupler with a second EDFA; and

(8) coupling an output of the second EDFA to a third optical isolator.

8. A method of manufacturing a bidirectional optical fiber amplifier comprising the steps of:

(1) providing a means for amplifying first and second optical signals traveling in opposite directions with first and second respective optical fiber amplifiers, the first and second optical signals having different frequencies;

(2) providing a means for separating a first path for the first optical signal from a second path for the second optical signal with first and second optical circulators coupled between the first and second optical fiber amplifiers; and

(3) providing a means for selectively passing an optical signal traveling in one direction and removing optical an optical signal traveling in another direction with first and second etalon filters respectively disposed in the first and second paths.