High-power 1.3 µm superluminescent diode

Superluminescent diodes with high output power (10 mW at 175 mA), wide spectral width (28 nm), low spectral modulation depth (<15%), wide frequency modulation bandwidth (570 MHz), and high single-mode fiber coupling efficiency (40%) are reported. The structure is based on a buried crescent laser structure with an antireflection coating and a "short-circuit" absorber to suppress lasing

Very high frequency GaAlAs laser field-effect transistor monolithic integrated circuit

A very low threshold GaAlAs buried heterostructure laser has been monolithically integrated with a recessed structure metal-semiconductor field-effect transistor on a semi-insulating substrate. At cw operation, the device has a direct modulation bandwidth of at least 4 GHz

Distinguishing Bots from Human Callers

Telephone users frequently receive unwanted calls from sales, advertising, or spam callers. Such calls may be made by automated agents or bots of such sophistication that they are often difficult to distinguish from human callers. This disclosure presents machine-learning techniques that enable differentiation of bots from human callers. Machine-learning models are trained to recognize artifacts that distinguish bot callers. Users can report callers as bots or humans, thereby enabling federated learning of differences between human callers and bots. A suspected bot caller is challenged with audio or visual captchas to further filter out bots. An incoming call that is confirmed as bot-initiated is either not delivered to the user, or the call recipient is alerted that the caller is likely a bot