Andrew Minh Phan

US Patent:

20110235164, Sep 29, 2011

Filed:

Mar 25, 2010

Appl. No.:

12/732118

Inventors:

Abhijeet D. Deore - Sunnyvale CA, US
Andrew Q. Phan - San Jose CA, US
Zhong Pan - Davis CA, US

International Classification:

H01S 3/30

US Classification:

359334

Abstract:

A system is provided that includes optical amplifiers provided upstream from an optical add-drop multiplexer (OADM). One of the optical amplifiers may be a Raman amplifier that supplies amplified light to another optical amplifier, such as an erbium doped fiber amplifier (EDFA), which, in turn, further amplifies and feeds the light to an input of the OADM. During turn-up, for example, the EDFA may initially be disabled, the power of the pump lasers of the Raman amplifier may be gradually increased until light input to the EDFA exceeds a power threshold at which the EDFA can amplify the input light. Light supplied to the EDFA does not have an excessive amount of power. Accordingly, at this point, the gain of the EDFA may be appropriately adjusted and then activated to supply optical signals to the OADM. Such optical signals may have a low power but not too low so as to prevent proper operation of downstream EDFA. Moreover, these optical signal do not have power that is so high as to cause “spiking.” As a result, cross-talk with optical signals added by the OADM is minimized, and such added optical signals may be sufficiently amplified by optical amplifiers downstream from the OADM.