Patent ID: 9720168
Date: 2017-08-01
CPC Classifications: G02B,G02F

Claim:
1. A wavelength selective optical switch comprising: a light input/output unit having a plurality of input/output ports; a polarization plane-independent wavelength dispersion element that splits incident light input from the optical input/output unit into spatially different angles for each wavelength, and synthesizes emergent light from different directions and outputs the light to the optical input/output unit; a condenser element that condenses the light split by the wavelength splitting element; a polarization splitter that: a space phase modulation element arranged so as to receive incident light deployed on an xy plane made up of an x-axis direction deployed according to wavelength and a y-axis direction orthogonal to the x-axis direction, and having numerous pixels arranged in a lattice on the xy plane, wherein, by changing a phase of a plurality of continuous pixels in the y-axis direction, the space phase modulation element changes refractive index characteristics of those pixels and reflection direction for each wavelength; and a space phase modulation element drive unit that changes phase shift characteristics for each wavelength and reflects light in a different direction for each wavelength by driving electrodes of each pixel arranged in an xy direction of the space phase modulation element, wherein the condenser element is a condenser element of a telecentric optics system in which light that reaches the face of the space phase modulation element is focused such that it becomes mutually parallel at any position, wherein the incident light applied to the light input/output unit is WDM signal light input to an input port of the plurality of input/output ports, and wherein, when the physical length in a wavelength dispersion direction per channel of WDM signal light on the face of the space phase modulation element is taken as d and the beam radius in the wavelength dispersion direction per channel is taken as w1, d/w1 is greater than 6.