  We propose a straightforward and effective approach to design, by
strain-engineering, photonic topological insulators supporting high quality
factors edge states. Chiral strain-engineering creates opposite synthetic gauge
fields in two domains resulting in Landau levels with the same energy spacing
but different topological numbers. The boundary of the two topological domains
hosts robust time-reversal and spin-momentum-locked edge states, exhibiting
high quality factors due to continuous strain modulation. By shaping the
synthetic gauge field, we obtain a remarkable field confinement and tunability,
with the strain strongly affecting the degree of localization of the edge
states. Notably the two-domain design stabilizes the strain-induced topological
edge state. The large potential bandwidth of the strain-engineering and the
opportunity to induce the mechanical stress at the fabrication stage enables
large scalability for many potential applications in photonics, such as tunable
microcavities, new lasers and information processing devices, including the
quantum regime.
