Hi!
Autonegotiation is an Ethernet procedure by which two connected devices choose common transmission parameters, such as speed, duplex mode, and flow control. Autonegotiation can be used by devices that are capable of different transmission rates, different duplex modes (half duplex and full duplex). (wiki).
Modern 10Gigabit optical links are point-to-point by the nature and use two different physical fibers, so links always have a capability to operate in full duplex mode. Transmission rates are always 10GE and always determined by the transceiver type. If operator uses 10GE transceivers there is no reason to downgrade this link to 1gbps. There is no need to provide interoperability of these technologies - 10GE optics is much expensive against 1GE. All the flexibility is guaranteed by transceiver types that operator can choose for particular link. If operator needs cheaper and less productive link - it will choose SFP 1000BASE transceivers. So there is no any ambiguity to negotiate.
JFYI, regarding copper links, there IS an autonegotiation procedure and device can signal its capability to run 10GBASE-T.
