Abstract: A light emitting element driving circuit drives a surface-emitting element, and the light emitting element driving circuit is equipped with a bias current driving circuit that supplies a generally constant bias current to the surface-emitting element, a modulation current driving circuit that supplies to the surface-emitting element a modulation current superimposed on the bias current, and a temperature detection circuit that detects the temperature of the surface-emitting element, wherein the modulation current driving circuit decreases the current amount of the modulation current, when the temperature detected rises. The bias current driving circuit may preferably supply the bias current to the surface-emitting element through a coil, and the modulation current driving circuit may preferably supply the modulation current to the surface-emitting element through a capacitor.

Abstract: To provide optical modules and optical transmission devices that are suitable for communication forms using multimode optical fibers, an optical module includes a surface-emitting type semiconductor laser that emits polarized light oscillating in a multimode which is preferentially oriented in two given polarization axes, and an optical member that demonstrates at least one function among a transmission function, a reflection function, a refraction function, and a diffraction function alternatively to a predetermined polarization. The optical member is disposed such that a principal plane thereof intersects with a traveling direction of emission light of the surface-emitting type semiconductor laser and a polarization axis of the polarization plane does not overlap with the polarization axes of the emission light of the surface-emitting type semiconductor laser.

Abstract: A light emitting element driving circuit drives a surface-emitting element, and the light emitting element driving circuit is equipped with a bias current driving circuit that supplies a generally constant bias current to the surface-emitting element, a modulation current driving circuit that supplies to the surface-emitting element a modulation current superimposed on the bias current, and a temperature detection circuit that detects the temperature of the surface-emitting element, wherein the modulation current driving circuit decreases the current amount of the modulation current, when the temperature detected rises. The bias current driving circuit may preferably supply the bias current to the surface-emitting element through a coil, and the modulation current driving circuit may preferably supply the modulation current to the surface-emitting element through a capacitor.

Abstract: To provide optical modules and optical transmission devices that are suitable for communication forms using multimode optical fibers, an optical module includes a surface-emitting type semiconductor laser that emits polarized light oscillating in a multimode which is preferentially oriented in two given polarization axes, and an optical member that demonstrates at least one function among a transmission function, a reflection function, a refraction function, and a diffraction function alternatively to a predetermined polarization. The optical member is disposed such that a principal plane thereof intersects with a traveling direction of emission light of the surface-emitting type semiconductor laser and a polarization axis of the polarization plane does not overlap with the polarization axes of the emission light of the surface-emitting type semiconductor laser.