Dispersive device and wavelength selective switch

Abstract

A dispersive device has a beam expanding optical system which includes first and second prisms each having a pair of faces inclined relative to each other, and expands light containing a plurality of wavelength components by passing the light through each of the faces of the first and second prisms; and a dispersive element which emits the light expanded by the beam expanding optical system, at different diffraction angles by the respective wavelength components. A direction of variation of an output angle of the light emitted from the beam expanding optical system due to temperature change is configured to be a direction to suppress variation of the diffraction angles of the respective wavelength components emitted from the dispersive element due to the temperature change.

Description

technical field [0001] The invention relates to a light splitting device and a wavelength selective switch. Background technique [0002] Japanese Patent Application Laid-Open No. 2007-163780 discloses a multi-wavelength spectroscopic device applied to a wavelength selective switch. The device has 2 diffraction gratings. With one diffraction grating, the diffraction efficiencies of P-polarized light and S-polarized light are the same at the short wavelength side of the wavelength range used, and with two diffraction gratings, the diffraction efficiencies of P-polarized light and S-polarized light are at the long end of the wavelength range used. The wavelength side is the same. According to the above configuration, the amount of angular dispersion is increased, and the wavelength dependence of the diffraction efficiency is offset to reduce the wavelength dependence of the diffraction efficiency. [0003] A wavelength dispersion device with a temperature compensation unit ...

AI Technical Summary

Problems solved by technology

As a result, since the wavelength components corresponding to the edge of the wavelength band deviate from the deflection region of the light deflection element, the wavelength band of usable wavelengths becomes narrow.

[0006] In addition, as shown in the wavelength dispersion device described in US Patent Application Publication No. 2009 / 0154876, if a prism for temperature compensation is additionally provided on the basis of a normal spectroscopic optical system, the number of parts will increase, which will become an obstacle to the optical system. One reason for system miniaturization

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