There is no generally accepted definition of exile poetry or poetry of exile nor positive agreement whether a category like this can have a theoretical signification. The notion of exile itself refers to very different historical situations.
However, there exists a tendency to unification of exile in poetry consisting in poets' relating to their precursors in exile and in using motifs from their poetry. A core of poems in which poets speak of their exile can make visible several presuppositions of poetry which are taken as self-evident usually.
That is primarily relation of a poet and poem to a community, language and place. A distance plays significant role in all three cases: poet is distanced from his home, his community and lives in an environment of a foreign language.
All this can influence topic and structure of a poem. Poetic attestations on exile can be read as autobiographical fictions (a model case represent Ovid's exile elegies), nevertheless, the fiction is shaped by the imaginary which forms a complementary to the situation of exile.
Here, Iser's distinction between the fictional (das Fiktive) and the imaginary (das Imaginäre) can be used. A poet is for example distanced from his home and he creates an idealized image of the home which is not only fictional, but it also forms an imaginary counterpart of the exile.
A poem surpasses a distance between exile and community and can constitute an imaginary community complementary to the situation of exile. There are two main poetic models of exile.
The first is physical banishment from home (with typical example of Ovid's exilic elegies); in the second model, the exile expresses the condition of human in the world. This second type has its roots in biblical myth of expulsion from the Paradise and is newly formulated and related to the condition of poet by Baudelaire in modern times.
The imaginary has a key role in both models as it creates a background for the reality on which can be showed what was not manifest. In this sense, exile and its distances means an imaginary opposite to the naively perceived reality.