What are the specified launched power and receive sensitivity of GPON and PtP networks?

In the case of fiber to the home (FTTH), gigabit packet optical networks (GPON) or point-to-point (PtP), what is the power of the emitted beam (source power)? Also, what is the sensitivity of the receiving device -- e.g., optical network terminal (ONT) or switch?

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The ITU-T Recommendation G.984.2 Amendment 1 (February 2006) specifies the generic optical power levels for a 2.4 Gbps downstream/1.2 Gbps upstream GPON system. For the optical line terminal (OLT), the mean launched power must be between +1.5 dBm and +5dBm and the receive sensitivity must be between -28 dBm and -8 dBm. For the ONT, the mean launched power must be between +0.5 dBm and +5 dBm and the receive sensitivity must be between -27 dBm and -8 dBm. Actual vendor implementations may vary, so check their specifications.

For active Ethernet point-to-point (PtP) networks, transmit power and receive sensitivity are functions of the optics used by the particular switching equipment. Cisco's 1000BASE-BX10-D/U Small Form-Factor Pluggable (SFP) Gigabit Interface Converters, for example, have a mean launched power between -9 dBm and -3 dBm and a receive sensitivity between -19.5 dBm and -3 dBm.

This was first published in August 2010

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