Various aspects of the present invention are directed to photonic devices, such as electro-optic modulators, passive filters, and tunable filters. The other end of the guiding tube is directly inserted into the air-inlet tube of the internal combustion engine. The crystalline polyester can be suitably used for a resin binder for toner for electrophotography and the like used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing, and the like; a polyester resin composition comprising the crystalline polyester. The controller is configured to select one of the first and second control signals for the switch in response to a change in an operating condition of the power converter.