Optical: systems and elements – Optical amplifier – Optical fiber
Reexamination Certificate
1999-08-04
2001-03-13
Moskowitz, Nelson (Department: 3662)
Optical: systems and elements
Optical amplifier
Optical fiber
C359S199200, C359S347000, C372S006000, C372S071000
Reexamination Certificate
active
06201637
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a long-wavelength optical fiber amplifier, and more particularly, to an optical fiber amplifier for amplifying a long-wavelength optical signal in the range of 1580 nanometers.
2. Related Art
In an optical transmission system, an erbium doped fiber amplifier (EDFA) can be used to directly amplify optical signals which become weak during transmission. This amplification of the optical signals can be performed without converting the optical signals into electrical signals. Thus, the transmission distance can be markedly increased.
I have found that a large amount of power can be required when amplifying a long-wavelength optical signal in the wavelength range of 1580 nanometers (nm). Unfortunately, there is not currently available an adequate method for efficiently and conveniently amplifying a long-wavelength optical signal.
SUMMARY OF THE INVENTION
To solve the above problems and others, it is an objective of the present invention to provide a long wavelength optical fiber amplifier for increasing the gain of long-wavelength amplification and suppressing short-wavelength amplification.
To solve the above problems and others, it is a further objective of the present invention to provide a long wavelength optical fiber amplifier for increasing the gain of long-wavelength amplification and suppressing short-wavelength amplification, by which population inversion of erbium ions necessary for long-wavelength amplification is realized with respect to erbium ions in an erbium doped fiber, by providing a reflector capable of reflecting amplified spontaneous emission (ASE) generated when amplifying signal light.
Accordingly, to achieve the above objectives and others, there is provided a long-wavelength optical fiber amplifier including an erbium doped optical fiber (EDF) for amplifying an input signal light having a wavelength in the range of 1580 nm using pump light, a pumping unit positioned in front of and to the rear of the erbium doped optical fiber, for supplying the pump light to the erbium doped optical fiber, and an amplified spontaneous emission (ASE) reflecting unit positioned in front of the erbium doped optical fiber and the pumping unit, for coupling amplified spontaneous emission generated in the erbium doped optical fiber to the long-wavelength input signal light and outputting the same to the erbium doped optical fiber.
According to another aspect of the present invention, there is provided a long-wavelength optical fiber amplifier including an erbium doped optical fiber for amplifying an input signal light having a wavelength in the range of 1580 nm using pump light, a pumping unit positioned in front of and to the rear of the erbium doped optical fiber, for generating the pump light to excite erbium ions in the erbium doped optical fiber, and an amplified spontaneous emission (ASE) reflecting unit positioned to the rear of the pumping unit, for reflecting amplified spontaneous emission generated in the erbium doped optical fiber to the erbium doped optical fiber.
According to still another aspect of the present invention, there is provided a long-wavelength optical fiber amplifier including an erbium doped optical fiber (EDF) for amplifying an input signal light having a wavelength in the range of 1580 nm using pump light, a pumping unit positioned in front of and to the rear of the erbium doped optical fiber, for generating the pump light to excite erbium ions in the erbium doped optical fiber, a first amplified spontaneous emission (ASE) reflecting unit positioned in front of the pumping unit, for coupling amplified spontaneous emission generated in the erbium doped optical fiber to the long-wavelength input signal light and inputting again the same to the erbium doped optical fiber, and a second amplified spontaneous emission reflecting unit positioned to the rear of the pumping unit, for reflecting amplified spontaneous emission generated in the erbium doped optical fiber to the erbium doped optical fiber and inputting again the same to the erbium doped optical fiber.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus, comprising: an optical fiber having an input port and an output port, receiving signal light to said input port, amplifying the signal light using pump light, outputting amplified signal light from said output port, the signal light having a wavelength at or near 1580 nanometers, said signal light traveling in a first direction; a pumping unit being connected to said input and output ports, supplying the pump light to said input and output ports; and a reflecting unit being connected to said pumping unit, coupling amplified spontaneous emission generated in said optical fiber with the signal light, conveying the amplified spontaneous emission coupled with the signal light to said input port.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a long-wavelength optical fiber amplifier apparatus, comprising: an optical fiber being erbium doped, said optical fiber amplifying a signal light having a wavelength at or near 1580 nanometers using pump light, said optical fiber having an input port and an output port, said optical fiber receiving the signal light at said input first port, the signal light traveling in a first direction; a pumping unit having a first pump section connected to said input port and a second pump section connected to said output port, said pumping unit generating the pump light to excite erbium ions in said optical fiber; and a reflecting unit being connected to said second pump section, said reflecting unit receiving amplified spontaneous emission traveling in said first direction from said output port through said second pump section, the amplified spontaneous emission being generated in said optical fiber, said reflecting unit reflecting the amplified spontaneous emission back to said output port of said optical fiber in a second direction opposite to said first direction.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides an apparatus, comprising: an optical fiber having an input port and an output port, being doped with erbium, receiving signal light at said input port, amplifying the signal light using pump light, outputting amplified signal light at said output port, the signal light having a wavelength at or near 1580 nanometers, the signal light traveling in a first direction; a pumping unit having a first pump section connected to said input port and a second pump section connected to said output port, said first and second pump sections generating the pump light to excite erbium ions in said optical fiber; a first reflecting unit being connected to said first pump section, receiving first amplified spontaneous emission traveling in a second direction from said input port through said first pump section, coupling the first amplified spontaneous emission with the signal light, and conveying the first amplified spontaneous emission coupled with the signal light to said input port of said optical fiber, the first amplified spontaneous emission being generated in said optical fiber, said second direction being opposite to said first direction; and a second reflecting unit being connected to said second pump section, receiving second amplified spontaneous emission traveling in said first direction from said output port through said second pump section, and reflecting the second amplified spontaneous emission back to said output port of said optical fiber in said second direction, the second amplified spontaneous emission being generated in said optical fiber.
The present invention is more specifically described in the following paragraphs by reference to the drawings attached only by way of example. Other ad
Kim Jeong-mee
Kim Sung-Jun
Nilsson Johan
Bushnell , Esq. Robert E.
Moskowitz Nelson
Samsung Electronics Co,. Ltd.
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