b and the combined optical beam 212. The beam correction sensor 226 can use the input optical beam 204b to determine how to adjust the path of the combined optical beam 212. For instance, the beam correction sensor 226 may sense the location of the input optical beam 204b on a focal plane array or other imaging device. As a particular example, the beam correction sensor 226 may represent a coudé optical position sensor (COPS). In some cases, the beam correction sensor 226 can provide measurements of angular and spatial beam error and may be configured to image optical components of the architecture 200.

A tracking correction block 228 can be used to adjust the path of the combined optical beam 212 based on the measurements captured by the beam correction sensor 226. For example, the tracking correction block 228 may include one or more fast steering mirrors or other optical devices that can adjust the direction of the combined optical beam 212 based on the measurements captured by the beam correction sensor 226. Effectively, this allows the auto-alignment beam (the input optical beam 204b) to be used to control the direction of the combined optical beam 212. One or more lenses or other optics 230 can be used to focus or otherwise out-couple the combined optical beam 212 from the architecture 200, such as in the form of the HEL beam 106.

The TIL beam 108 (which is based on the input optical beam 204c) produced by the architecture 200 is transmitted, and return illumination 232 represents optical energy from the TIL beam 108 as reflected (such as from a target 104). The return illumination 232 is provided to a tracking sense block 234, which provides the return illumination 232 to a high-speed tracking sensor 236. The tracking sensor 236 can use the return illumination 232, such as to generate images of the target 104 or to identify information about the target 104 (like its distance and angle relative to the architecture 200). In some cases, the tracking sensor 236 may represent a camera or other sensor for target acquisition and tracking. In particular embodiments, the tracking sensor 236 may represent a 30 Hz camera or other imaging device that can detect short-wave infrared (SWIR), near infrared (NIR), or other optical radiation. Output from the tracking sensor 236 may be used in any suitable manner, such as to provide imaging feedback or to position or reposition the HEL beam 106 on the target 104.

In addition, the architecture 200 includes a bypass optical beam sensing and correction (S/C) unit 238. The sensing and correction unit 238 can capture sensor measurements associated with the input optical beam 204c and can modify the input optical beam 204c so that the resulting TIL beam 108 is directed in a desired direction and has one or more desired characteristics (such as divergence angle). The sensing and correction unit 238 is described as a “bypass optical beam” sensing and correction unit since the input optical beam 204c is spatially separated from the combined optical beam 212, allowing the input optical beam 204c to bypass some of the optical modifications performed on the combined optical beam 212. Example implementations of the sensing and correction unit 238 are shown in FIGS. 3 and 4, which are described below. Note that the sensing and correction unit 238 may be positioned at any suitable location within the architecture 200 at which the sensing and correction unit 238 can receive and modify the input optical beam 204c. Two example locations are identified in FIG. 2, one within the input beam processing unit 206 and one within the beam director unit 218. However, these locations are for illustration and explanation only.

Although FIG. 2 illustrates one example of an architecture 200 supporting compact closed-loop bypass optical beam sensing and correction, various changes may be made to FIG. 2. For example, components can be added, omitted, combined, further subdivided, replicated, or placed in any other suitable configuration in FIG. 2 according to particular needs.

FIGS. 3 and 4 illustrate example devices supporting compact closed-loop bypass optical beam sensing and correction in accordance with this disclosure. More specifically, FIGS. 3 and 4 illustrate example embodiments of the bypass optical beam sensing and correction unit 238 of FIG. 2. For ease of explanation, the devices shown in FIGS. 3 and 4 may be described as being used in the architecture 200, which can be used in the system 100 of FIG. 1. Also, the devices shown in FIGS. 3 and 4 may be described as being used to receive and modify a TIL beam 108 that is spatially separated from an HEL beam 106. However, the devices shown in FIGS. 3 and 4 may be used in any other suitable architectures or systems and for any other suitable purposes, and the devices shown in FIGS. 3 and 4 may be used with any other suitable types of optical beams.

As shown in FIG. 3, a beamsplitter 302 is used to separate the combined optical beam 212 and the input optical beam 204c (as processed using earlier functions). Here, the beamsplitter 302 is used to reflect the combined optical beam 212 and transmit the input optical beam 204c, although the opposite approach may be used. In some embodiments, the reflection or transmission can be based on the wavelengths of optical signals, such as when the beamsplitter 302 is reflective at the wavelength(s) of the combined optical beam 212 and transmissive at the wavelength(s) of the input optical beam 204c (or vice versa). The beamsplitter 302 includes any suitable structure configured to reflect and transmit electromagnetic energy. In some cases, the beamsplitter 302 may form at least part of the pick-off unit 222 described above. Also, note that the beamsplitter 302 may be replaced by another optical device, such as a mirror that can reflect the combined optical beam 212 without interacting with the input optical beam 204c. The combined optical beam 212 is modified using one or more beam control components 304. In some cases, the one or more beam control components 304 may represent the beam correction sense block 224, the tracking correction block 228, and the optics 230 described above.

The bypass optical beam sensing and correction unit 238 receives the input optical beam 204c, which is bypassing the beam control components 304. The bypass optical beam sensing and correction unit 238 here includes a divergence controller 306, which can be used to control the divergence of the input optical beam 204c. The divergence of the input optical beam 204c relates to the increase in beam diameter or radius as distance from the bypass optical beam sensing and correction unit