Photo signal amplification transmission system

• US 6,233,078 B1
• Filed: 04/21/1998
• Issued: 05/15/2001
• Est. Priority Date: 04/25/1997
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Harano, Hiroshi, Maruyama, Naoki
• Primary Examiner(s): NEGASH, KINFE MICHAEL
• Application Number:
  US09/063,674
• Time in Patent Office: 1,120 Days
• Field of Search: 359/134, 359/124, 359/160, 359/341, 359/179, 359/187, 359/337
• US Class Current: 398/14
• CPC Class Codes: H04B 10/2931 using AGC H04B10/294 takes precedence
• CPC Class Codes: H04B 10/2935 with a cascade of amplifiers
• CPC Class Codes: H04B 10/2942 using automatic gain control [AGC] H04B10/296 takes precedence
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems

Abstract

In a conventional photo signal amplification transmission system, since control is performed to make constant an output power, total output powers of all wavelengths are made constant when a multi-wavelength transmission is made. An output power of one wavelength is decreased and deviated from an optimum power. To solve the problem, a transmission photo amplifier 3, a relay photo amplifier 4 and a receiving photo amplifier 5 are provided with wavelength number information management sections 11, 12 and 13, respectively. An amplifying means is controlled in accordance with the number of wavelengths of the multi-wavelength signal which is obtained by the wavelength number information management sections. The wavelength number information management sections 11 to 13 multiplex a wavelength number information signal onto an optical fiber cable 6 and renews the signal.

Claims

1. A photo signal amplification transmission system for amplifying to a desired level a photo signal to be transmitted via an optical fiber cable and transmitting the photo signal at a transmission end, the photo signal to be transmitted is a multi-wavelength signal constituted of plural multiplexed signals having different wavelengths and a wavelength number information signal identifying a number of wavelengths in the photo signal, the photo signal amplification transmission system comprising:

an amplifying means controlled in accordance with the number of wavelengths identified in the wavelength number information signal; and

means for batch-amplifying the photo signal to the desired level in accordance with the number of wavelengths before being transmitted.

2. The photo signal amplification transmission system according to claim 1 wherein said amplifying means is provided with an activating laser beam source, a WDM (wavelength division multiplex) photo coupler for combining an activating light from the activating laser beam source with said multi-wavelength signal and an erbium doped fiber.

3. The photo signal amplification transmission system according to claim 1 wherein the amplifying means is controlled in accordance with said number of wavelengths by monitoring the amplified output and transmitting said wavelength number information to an APC circuit for feedback-controlling the activating laser beam source.

4. A photo signal amplification transmission system for amplifying to a desired level a photo signal transmitted via an optical fiber cable and transmitting the photo signal at a relay point, said transmitted photo signal is a multi-wavelength signal constituted of plural multiplexed signals having different wavelengths and a wavelength number information signal identifying wavelength number information, said photo signal amplification transmission system comprising:

a wavelength number information management section for receiving and transmitting the wavelength number information; and

an amplifying means controlled in accordance with the wavelength number information obtained by said wavelength number information management section;

wherein the photo signal is batch-amplified to the desired level in accordance with the wavelength number information before being transmitted.

5. The photo signal amplification transmission system according to claim 4, wherein said wavelength number information management section separates and receives a wavelength number information signal which is transmitted while being multiplexed on a main signal by using a wavelength different from the wavelength of the photo signal (main signal) transmitted from the transmission end via said optical fiber cable, and multiplexes the wavelength number information signal onto the main signal which has been amplified by the amplifying means by using the wavelength different from the wavelength of the main signal before transmitting the wavelength number information signal.

6. A photo signal amplification transmission system for amplifying a photo signal transmitted via an optical fiber cable to a desired level at a receiving end, said transmitted photo signal is a multi-wavelength signal constituted of plural multiplexed signals having different wavelengths and a wavelength number information signal identifying wavelength number information, said photo signal amplification transmission system comprising:

means for receiving the wavelength number information from the wavelength number information signal; and

an amplifying means controlled in accordance with the wavelength number information obtained by said means;

wherein the photo signal is batch-amplified to the desired level in accordance with the number of wavelengths.

7. The photo signal amplification transmission system according to claim 6, wherein said means for receiving said wavelength number information separates and receives the a wavelength number information signal which is transmitted while being multiplexed on said main signal by using a wavelength different from the wavelength of the photo signal (main signal) transmitted from the transmission end or the relay point via said optical fiber cable.