High power pulse shaping fiber laser for high data rate free space telecommunication systems

• US 7,256,930 B2
• Filed: 04/15/2004
• Issued: 08/14/2007
• Est. Priority Date: 04/15/2003
• Status: Active Grant

• Current Assignee: Liu Jian
• Original Assignee: Liu Jian
• Inventors: Liu, Jian
• Primary Examiner(s): HUGHES, DEANDRA M
• Application Number:
  US10/825,746
• Publication Number:
  US 20050036525A1
• Time in Patent Office: 1,216 Days
• Field of Search: 359/264, 359/337.21, 359/349
• US Class Current: 359/337.1
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0078 Frequency filtering
• CPC Class Codes: H01S 3/0085 Modulating the output, i.e. the laser beam is modulated outside the laser cavity
• CPC Class Codes: H01S 3/06708 Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering optical fibres as passive waveguides G02B6/02
• CPC Class Codes: H01S 3/0675 Resonators including a grating structure, e.g. distributed Bragg reflectors [DBR] or distributed feedback [DFB] fibre lasers
• CPC Class Codes: H01S 3/06758 Tandem amplifiers
• CPC Class Codes: H01S 3/0941 of a laser diode
• CPC Class Codes: H01S 3/1608 erbium

Abstract

An amplified laser source for amplifying a laser projection that includes a diode laser source modulated by a pulse generator applying an alternate high and low voltages higher and lower than a threshold voltage for projecting a modulated optical signal. The laser source further includes a first erbium-doped fiber (EDF) for amplifying the modulated optical signal. The laser source further includes a set of Bragg gratings for receiving the modulated optical signal from the first EDF for reflecting a grating-specific pulse-distortion-reduced optical signal. The laser source further includes an electro-absorption (EA) modulator synchronized with the pulse generator for increasing an extinction ratio of the optical signals. The laser source further includes a second erbium doped fiber (EDF) for receiving and amplifying the optical signal from the EA modulator wherein the second erbium doped fiber (EDF) having a length of several meters and a diameter greater than or equal to thirty-five micrometers.

Claims

1. An amplified laser source for amplifying a laser projection comprising:

a diode laser source modulated by a pulse generator applying an alternate high and low voltages higher and lower than a threshold voltages projecting a modulated optical signal;

a first erbium doped fiber (EDF) for amplifying said modulated optical signal;

a set of Bragg gratings for receiving said modulated optical signal from said first EDF for reflecting a grating-specific pulse-distortion-reduced optical signal and a circulator for transmitting said grating-specific pulse-distortion-reduced optical signal to a second erbium doped fiber for further amplification.

2. The amplified laser source of claim 1 further comprising:

an Electro-Absorption (EA) modulator synchronized with said pulse generator for increasing an extinction ratio of said optical signals.

3. The amplified laser source of claim 2 further comprising:

said second erbium doped fiber (EDF) receiving and amplifying said optical signal from said Electro-Absorption (EA) modulator.

4. The amplified laser source of claim 3 wherein:

said second erbium doped fiber (EDF) having a large mode area.

5. The amplified laser source of claim 3 wherein:

said second erbium doped fiber (EDF) having a length of several meters and a diameter approximately thirty-five micrometers.

6. The amplified laser source of claim 2 wherein:

said EA modulator is a semiconductor Electro-Absorption (EA) modulator.

7. An amplified laser source for amplifying a laser projection comprising:

a diode laser source modulated by a pulse generator applying an alternate high and low voltages higher and lower than a threshold voltages projecting a modulated optical signal;

a first erbium doped fiber (EDF) for amplifying said modulated optical signal;

a set of Bragg gratings for receiving said modulated optical signal from said first EDF for reflecting a grating-specific pulse-distortion-reduced optical signal;

a circulator for transmitting said grating-specific pulse-distortion-reduced optical signal to an EA modulator synchronized with said pulse generator for increasing an extinction ratio of said optical signals; and

a second erbium doped fiber (EDF) for receiving and amplifying said optical signal from said EA modulator wherein said second erbium doped fiber (EDF) having a length of several meters and a diameter approximately thirty-five micrometers.

8. An amplified laser source for amplifying a laser projection comprising:

a first laser gain medium for amplifying said laser projection for projecting to a set of Bragg gratings for reflecting a grating-specific pulse-distortion-reduced optical signal and a circulator for transmitting said grating-specific pulse-distortion-reduced optical signal to a second laser gain medium for further amplification; and

an EA modulator synchronized with said pulse generator for increasing an extinction ratio of said optical signals.

9. The amplified laser source of claim 8 further comprising:

a diode laser source modulated by a pulse generator applying an alternate high and low voltages higher and lower than a threshold voltages projecting a modulated optical signal to said Bragg gratings.

10. The amplified laser source of claim 9 wherein:

said first laser gain medium comprising a first erbium doped fiber (EDF) for amplifying said modulated optical signal.

11. The amplified laser source of claim 8 wherein:

said second laser gain medium comprising a second erbium doped fiber (EDF) for receiving and amplifying said optical signal from said EA modulator.

12. The amplified laser source of claim 11 wherein:

said second erbium doped fiber (EDF) having a large mode area.

13. The amplified laser source of claim 11 wherein:

said second erbium doped fiber (EDF) having a length of several meters and a diameter approximately thirty-five micrometers.

14. The amplified laser source of claim 8 wherein:

said BA modulator is a semiconductor BA modulator.