A wavemeter for determining a wavelength of an incident optical beam comprises four optical components, each being arranged in the incident optical beam or in a part of it, providing a path with a respective effective optical length, and generating a respective optical beam with a respective optical power depending on the wavelength of the incident optical beam. The optical powers oscillate periodically with increasing wavelength, and a phase shift of approximately pi/2 is provided between two respective pairs of the four optical components. Respective power detectors are provided, each detecting a respective one of the optical powers. A wavelength allocator is provided for allocating a wavelength to the incident optical beam based on the wavelength dependencies of the detected first, second, third, and fourth optical powers.
An electronically tuned, wavelength-dependent optical detector is provided. The electronically tuned, wavelength-dependent optical detector is a modified metal-semiconductor-metal photodetector including a comb-like metal electrode at a common voltage and metal electrodes each supplied with a control voltage by a voltage means. The wavelength to be detected in an optical input illuminating the detector is selected based on the set of control voltages applied to the metal electrodes. In another embodiment of the invention, the wavelength to be detected with the electronically tuned, wavelength-dependent optical detector is also selected using a standing wave generator, such as an interferometer, to produce a spatially varying light intensity on the surface of the electronically tuned, wavelength-dependent optical detector. Electronic wavelength demultiplexing is also provided. Design flexibility can be obtained by providing two or more optical patterns at a detector surface, each pattern having a different wavelength dependence.
