Abstract: Sacrificial optical test structures are constructed upon a wafer (100) of pre-cleaved optical chips (10) for testing the optical functions of the pre-cleaved optical chips (10). The sacrificial optical structures are disabled upon the cleaving the optical chips (10) from the wafer (100) and the cleaved optical chips (10) can be used for their desired end functions. The test structures may remain on the cleaved optical chips (10) or they may be discarded.

Abstract: An optical autocorrelator comprises an optical waveguide (40) of semiconductor material which exhibits two photon absorption at a wavelength at which the autocorrelator is intended to operate. Reflecting means (46) are provided at a part of the waveguide which is remote to an end (42) in which an optical pulse (44) is input for reflecting the optical pulse such as to generate counter-propagating optical pulses in the waveguide. A plurality of electrodes (481-48N) are disposed along the waveguide for measuring a two photon absorption photocurrent (i1-in) generated in the waveguide by the counter-propagating optical pulses.

Abstract: An optical autocorrelator comprises an optical waveguide (40) of semiconductor material which exhibits two photon absorption at a wavelength at which the autocorrelator is intended to operate. Reflecting means (46) are provided at a part of the waveguide which is remote to an end (42) in which an optical pulse (44) is input for reflecting the optical pulse such as to generate counter-propagating optical pulses in the waveguide. A plurality of electrodes (481-48N) are disposed along the waveguide for measuring a two photon absorption photocurrent (i1-in) generated in the waveguide by the counter-propagating optical pulses.