| 摘要 |
<p>A helical feedback (HFB) is disclosed, the HFB structure including an optical waveguide (32) having a core, a distributed optical structure (38), such as a Bragg grating, formed in the waveguide (32) along a light propagation direction of the waveguide (32), wherein the distributed optical structure (38) exhibits a helical pitch that is greater than a linear component of a period of the distributed optical structure (38) along the propagation direction. The HFB structure can be produced by twisting the waveguide (32), forming the distributed optical structure (38) in the core of the twisted waveguide (32), and relaxing the waveguide (32). The HFB structure is suitable for use in a HFB laser exhibiting a single lasing polarisation state.</p> |
